DISCUSSION - 202307-202402 Flashcards

Question

Compagnone - 2023 - VCOT - Thoracolumbar Intervertebral Disk Extrusion in Dogs - Do Onset of Clinical Signs, Time of Surgery, and Neurological Grade Matter ?.pdf

Answer 1

In our population, the main factors in ﬂuencing the clinicaloutcome were neurological grade 0 at presentation and anacute onset of clinical signs. In previous studies, functionalrecovery fordogspresenting with a neurologicalgrade0 variedbetween 38 and 86%,3,4,6,31,32which is higher than our popu-lation (32%) and it was not associated with immediacy ofsurgery.25In the present study, 13.5% of dogs had an unsuc-cessful outcome, either maintaining their preoperative statusor experiencing a disease progression or myelomalacia, whichis marginally lower compared to a previous study.33In our study, the rate of onset was signi ﬁcantly associatedwith lower-grade discharge and degree of recovery, suggest-ing that cases presented with peracute/acute onset have aslower recovery and a worse overall outcome. This is inagreement with previous studies,2,3,6,9and based on ourﬁndings, we believe that the rate of onset should be consid-ered a reliable prognostic factor in the clinical setting, alongwith the neurological grade at presentation.Within the dogs included in this study, 13 dogs thatpresented with a grade 4 deteriorated immediately followingdecompressive surgery and were discharged with grade 0 to2. Deterioration of the neurological status following surgeryis a well-known complication of IVDE.32Of these dogs, 12were operated on by residents and there were not anyrecords of intraoperative complications. It could be specu-lated that this relatively high postoperative morbidity ratecould have been caused by an excessive manipulation of thespinal cord during surgery, lack of surgical expertise, or acombination of both. The experience of the primary surgeonhas been previously identi ﬁed as a signi ﬁcant risk factor fordevelopment of postoperative adverse events.34The execution of fenestration of the affected disk duringdecompressive surgery has been recommended in dogs toprevent further extrusion of the nucleus pulposus in theearly postoperative period, which may result in recurrence ofthe compression.11,20,35 –37However, its bene ﬁts remaincontroversial.20,38 –40In our population of dogs presentedwith a neurological grade between 0 and 3, performance offenestration during surgery seemed to be associated with afaster return to ambulation ( p¼0.033). Fenestration wouldnot be expected to directly in ﬂuence time of recovery, butrather provide a prophylactic measure against possiblerecurrence. We could speculate that a portion of the diskmaterial left behind could herniate in the early postoperativeperiod in those dogs in which fenestration was not per-formed, and therefore negatively affect the return to ambu-lation. This could not be con ﬁrmed in this study as dogs werenot routinely re-imaged following surgery.In the present study, there was a correlation between theDM/L2 ratio measured on CT images, MRI, or both, and therate of onset ( p¼0.002) and neurological grade at presenta-tion ( p<0.001) and at discharge ( p¼0.032). This means thatdogs with more extruded disk material were also more likelyto have an acute rate of onset and a worse neurological gradeboth at presentation and at discharge. This ratio does notspeci ﬁcally characterize the degree of spinal cordFig. 1 A representation of the degree of recovery for each presentingneurological grade category..compression, but instead gives the clinician a basic percep-tion of the amount of herniated intervertebral disk material.Ourﬁndings suggest that during a peracute/acute onset ofIVDE a larger volume of disk material is extruded, and,consequentially, a more severe spinal cord impact and dam-age is sustained. This re ﬂects clinically in a rapid rate ofonset, a worse neurological grade at presentation, and aworse neurological grade at discharge.Our study has several limitations. Being a retrospectivestudy, a bias on when to perform decompressive surgery couldnot be excluded. Several surgeons were involvedwith the casesincluded in our study, and this poses inconsistency in thedecision on when to operate dogs presented with IVDE, as wellas a nonstandardized clinical approach, surgical technique,and experience, which could all have in ﬂuenced the variablesand outcome for some patients, and ultimately our results.The choice to operate sooner could have been in ﬂuencedby the rate of onset, severity of the neurological grade onpresentation, or both combined, and it appears likely in ourstudy given that the lower was the grade at presentationand/or the faster was the rate of onset, the shorter was thetime between presentation and surgery in most dogs.In conclusion, we did not ﬁnd a signi ﬁcant correlationbetween duration of clinical signs, time between onset ofneurological signs and spinal surgery, and overall outcome.However, the strong correlation found between the rate ofonset and neurological grade at presentation, and the recoverytime and overall outcome might constitute valuable prognos-tic information for surgeons dealing with IVDE. Furthermore,fenestration of the affected disks seems to result in a morepositive outcome, which supports the recommendation ofperforming this procedure during IVDE surgery.Due to the retrospective nature of this study and thenumerous variables involved as previously stated, caution isrequired when interpreting these results. Further studies,preferably prospective, are required to better de ﬁne the idealsurgical timing and prognostic factors associated with theoutcome in dogs surgically treated for IVDE.

Answer 2

Both methods offered good intra- and interobserveragreement for the measurement of L Max. While theintraobserver agreement for the measurement of L Minwas good for the functional method, it was only moderatefor the anatomically adjusted method. Conversely, theanatomically adjusted method offered good interobserveragreement for LMin, whereas it was moderate for thefunctional method. We found good and moderateintraobserver agreement for ΔL using the functional andanatomically adjusted methods, respectively. The interob-server agreement for ΔL using both the functional andanatomically adjusted methods was good. Furthermore,we found moderate intra- and interobserver agreementfor the grade of dynamic nasopharyngeal collapse usingboth methods, except for the interobserver agreement ingrading using the anatomically adjusted method, whichwas fair (0.378).There are several sources of variability in both themeasurement methods. For instance, observers mighthave difficulty aligning the fiducial marker on theselected point on the screen. In addition, they might havedifficulty deciding the point of the minimum height ofthe nasopharyngeal lumen and recognizing whetherthere was a complete or near-complete collapse. In par-ticular, attention was needed to distinguish the collapsingnasopharynx during inspiration from physiological swal-lowing movements. The fluoroscopic videos were editedto include at least two breathing cycles undisturbed byswallowing or other motions. The rationale behind thisdesign was to save the time of the observers, as substan-tial stoppage during recordings has poor diagnostic value.Observers were asked to choose the breathing cycle withthe most severe dorsoventral narrowing of the nasophar-ynx. Therefore, the observers may have measured differ-ent breathing cycles. Theoretically, we could have askedthe observers to evaluate a specified breathing cycle.Although the variability of the change in the dorsoventralnasopharyngeal dimensions between different breathingcycles has not yet been reported, it appears reasonable toassume that such variability exists and, therefore, allow-ing the observers to choose which breathing cycle to mea-sure would be more appropriate for clinical use. Thus,minimal, maximal, and mean changes in dorsoventralnasopharyngeal dimensions could be the subjects of fur-ther studies.Owing to the retrospective nature of the study, wecould not choose a position different from lateral recum-bency, such as normal standing or sternal recumbency, asthe remote-controlled X-ray diagnostic system with a fluo-roscopy table (Axiom Iconos R200, Siemens AG, Erlangen,Germany) employed at the time would not allow suchpositioning. Fixating a brachycephalic dog in the lateralposition may increase its stress level, potentially leading tothe deterioration of its already compromised breathing.Therefore, the protocol at our institution at the time wasto abort the examination if the patient did not tolerate thelateral position.Despite these limitations, one observer (a diplomate ofthe European College of Diagnostic Imaging) achievedexcellent intraobserver agreement in measuring the ratioof dynamic nasopharyngeal change using both methods(correlation coefficients >0.9). Consequently, the observerreached very good intraobserver agreement for the gradingof nasopharyngeal collapse using the functional methodand good agreement using the anatomically adjustedmethod (correlation coefficients 0.887 and 0.803, respec-tively). It is plausible that the effects of profound trainingof this observer allowed for higher agreement, althoughlarger groups of observers are needed to more stronglysupport this conclusion.Our study was not designed to assess the prevalence ofnasopharyngeal collapse. However, when considering onlythe mean values from the first and second observationsperformed by Observer 1, partial or complete collapse waswidespread (83.3% for the functional method and 86.1%for the anatomically adjusted method). This is slightlyhigher than the previously reported incidence of 72% forbrachycephalic breeds.7The reason for this increase inincidence could be explained by the increased sensitivityof our methodology, geographical differences betweenstudied populations, and/or coincidence due to selectionbias caused by the exclusion of several fluoroscopic exami-nations from our study due to poor quality. In our study,the anatomical technique in the hands of the radiologistled to more common identification of complete than par-tial collapse. This is unexpected because the anatomicallyadjusted method places the measurement in a given loca-tion. The expectation was that because of that, someunderestimation of the severity of the collapse could occur.The observations were performed on dogs with brachyce-phalic airway obstruction syndrome before surgery. Anoverlong soft palate is expected to occur commonly. Insuch a situation, the tip of the epiglottis elevates the softpalate, causing further narrowing of the airway beyondwhat would be caused by the collapsing dorsal structures.Therefore, the observers were instructed not to considerVODNAREK ET AL . 93 1532950x, 2024, 1, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.13971 by Cochrane France, Wiley Online Library on [05/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensethe parts of the nasopharynx caudal to the most rostralextremity of the epiglottis for the measurements. It is,therefore, possible that while Observer 1 was using thefunctional method, he might have found some completecollapses to be located too caudally for consideration buthave found those to be included in the examined area afterperforming the measurement with the help of the tangen-tial line to the rostral-most end of the epiglottic cartilageusing the anatomically adjusted method.Although using an established grading system mightseem easier for clinical communication, introducing anycutoffs to continuous data leads to an increase in the vari-ability of the assessment. For example, dogs with a ΔLo f0.49 and those with a ΔL of 0.51 are likely to be clinicallysimilarly affected despite having different grades. Con-versely, dogs with a respective ΔL of 0.51 and 0.99 wouldlikely be differently affected, despite having the samegrade. We hypothesized that both methods (functionaland anatomically adjusted) would offer high intra- andinterobserver agreement and would therefore be reliablefor evaluating nasopharyngeal collapse in two brachyce-phalic breeds (French bulldogs and pugs). An anatomi-cally adjusted method was developed to reduce thevariability of the measurements; however, our results didnot support this hypothesis because the functionalmethod delivered marginally better agreement for ratiosand grading with the exception of the interobserveragreement for grading, where the anatomically adjustedmethod performed better. Due to the considerable vari-ability among observers, we did not consider a statisticalcomparison between the two methods. However, such acomparison might be matter of future studies employingonly observers with speciality training in imaging.In conclusion, the global intra- and interobserveragreement of two-dimensional measurements of thechanges in nasopharyngeal dimensions during breathingin a population of brachycephalic dogs was good to mod-erate, indicating considerable variability in fluoroscopicevaluation of dynamic changes in the dorsoventral naso-pharyngeal dimensions. Although the repeatability of theproposed methodology among veterinarians withoutimaging specialty training may be lower, both techniquesmay achieve higher repeatability among experiencedradiologists. None of the methods was superior to theother. Furthermore, we conclude that the use of the ratioof the dynamic change of the dorsoventral nasopharyn-geal dimensions may be more appropriate than the use ofgrades; it not only avoid introducing cutoffs withunknown clinical relevance, but it also offered margin-ally better global intra- and interobserver agreements inour study. Further studies comparing interobserver agree-ment among trained specialists are required to determinewhich of the studied methods offers higher intra- andinterobserver repeatability and clinical usefulness. Fur-thermore, future research should investigate the impactof nasopharyngeal collapse on respiration, prognosis, andthe effect of airway surgery on further progression orimprovement of nasopharyngeal collapse.AUTHOR CONTRIBUTIONSVodnarek J, MVDr: Contributed to the study design, pro-posal of the measurement method, and acquisition, ran-domization, and blinding of the data. The same authoralso acquired and prepared the data for the observers,performed the blinded observations, collected data fromthe observers, prepared data for statistical evaluation,drafted the manuscript, and approved the final versionfor publication. Ludewig E, ProfDrMedVetHabil,DECVDI and Vali Y, DrMedVet, DVM, DVSc: Contrib-uted to the study design, performed the blinded observa-tions, edited the manuscript, and approved the finalversion for publication. Dupré G, ProfDrMedVet, DECVS:Contributed to the conception of the study and studydesign, performed the blinded observations, edited themanuscript, and approved the final version for publication.Lyrakis M, PhD and Dolezal M, DrNatTech, MSc: Per-formed the statistical analyses of all the data, edited themanuscript, and approved the final version for publication.ACKNOWLEDGMENTSThe authors would like to thank to PD Dr. med. vet.habil. Barbara Bockstahler for the supervision of ourresearch group and help with manuscript editing.CONFLICT OF INTEREST STATEMENTThe authors declare no conflict of interest related to thisreport.ORCIDJakub Vodnarekhttps://orcid.org/0000-0002-8043-8189Yasamin Vali https://orcid.org/0000-0002-6090-0663

Answer 3

In this study, the majority of dogs undergoing surgical intervention for a left-to-right shunting PDA were female (73.9%) small-breed dogs < 1 year of age, which is con -sistent with previous reports.3,8,14 Two hundred five (65%) dogs had evidence of MR at presentation; however, there was no correlation between presence or degree of MR and an increased risk of intraoperative hemorrhage, thereby re -jecting our hypothesis. Intraoperative hemorrhage did oc -cur at the higher end of the previously reported range5,6,8 in this study (10.8%), with intraoperative hemorrhage from the PDA vessel occurring in 6.3% of patients. Based on avail -able data, our hypothesis that intraoperative hemorrhage would occur at a higher rate could not be rejected due to our reported rate falling within the previously reported ranges. The occurrence of intraoperative hemorrhage was not correlated to survival. The short- and long-term sur -vival rates in this study were similar to previous reports,3,7 thereby supporting our hypothesis.Multiple studies have investigated preexisting patient factors and their association with intraoperative compli -cations, short-term outcome, and long-term prognosis in dogs with a left-to-right shunting PDA.1–3,5,7,8,14 A study by Bureau et al7 reported that preexisting factors such as age, weight, and right atrial dilation were negative prog -nostic indicators for survival; however, a later report8 in 2007 showed that there was no correlation between age and patient size in terms of successful treatment. Our Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 07/22/23 07:43 AM UTC6 study found that there is no correlation between age or weight of the patient and occurrence of intraoperative hemorrhage, which supported the conclusions reported in the 2007 study.8A review15 of 100 cases in 1976 found that dogs di -agnosed with atrial fibrillation and MR had a 50% mortality rate within 1 month of surgery. The mortality rate for dogs with MR was improved to 94% at 1 year in a 2005 review7 of 52 cases, which is similar to findings in our study. While 50% of patients in our study had some degree of MR, there was no association between the presence or severity of MR and an increased risk of intraoperative hemorrhage. Addi -tionally, there was no correlation between the presence or severity of MR at the time of surgery and short- or long-term survival, including the cases with documented severe MR. A study8 in 2007 investigated the long-term outcome for dogs undergoing either surgical ligation or transarte -rial catheter occlusion for treatment of a PDA and found that the presence of left-sided CHF preoperatively was associated with a higher mortality rate postoperatively. In our study, 10% of dogs had a history of left-sided CHF and 14% had evidence of left-sided CHF at presentation, with neither having an impact on short- or long-term outcome. However, there was an association between the presence of left-sided CHF at presentation and intraoperative hem -orrhage. It is possible that the presence of left-sided CHF and associated volume overload is secondary to a larger-diameter PDA. The PDA may be friable due to lower levels of collagen and higher levels of elastin and are therefore at a higher risk of tearing during dissection.16 It is important to note that the aforementioned studies and our current study had a low number of overall adverse events, which impacted the power in detecting associations between patient factors and intraoperative hemorrhage. How -ever, significant advancements have been made in the detection, monitoring, and medical management of CHF, which likely contribute to the improvement in survival and outcome for patients undergoing ligation of a PDA with concurrent left-sided CHF.In 2014, Saunders et al3 reviewed 520 cases to determine the long-term outcome of dogs diagnosed with a left-to-right shunting PDA and determined that LA:Ao ratio was correlated to perioperative mortality with the predicted risk of perioperative death increas -ing from 2% with a normal LA:Ao ratio, up to 20% if the LA:Ao ratio was ≥ 2.5. While not statistically significant, our study did show that the association between the LA:Ao ratio and risk of intraoperative hemorrhage may be clinically significant. Of the dogs with known LA:Ao ratios that experienced intraoperative hemorrhage, 60% had an abnormal LA:Ao ratio. This association could help explain the previously reported increased risk of perioperative death, as it is feasible that a dilated left atrium could result in a more difficult dissection due to the proximity of the left atrium to the pulmonary artery and potential alteration of normal anatomic orientation with left atrial enlargement. The majority of hemor -rhage associated with PDA dissection occurred medial to the shunt vessel, so it is possible that the origin of the bleed was actually from a perforated large atrium instead of the medial wall of the PDA. Additionally, as mentioned above, an enlarged left atrium may indicate more severe volume overload secondary to a larger PDA diameter, thereby resulting in a larger shunt frac -tion and more friable PDA vessel, increasing the risk of intraoperative hemorrhage and mortality.16 The LA:Ao ratio was unknown in 25% of cases and there was not a standardized method of measuring this ratio, so it is possible that additional data points may have allowed this association to be statistically significant.Previous reports have cited the risk of intraopera -tive hemorrhage to be anywhere from 6.25% to 15%; however, reports of intraoperative hemorrhage impact -ing overall mortality vary. In a study6 of 64 cases, the risk of intraoperative hemorrhage was reported to be 6.25%, and the mortality risk increased significantly from 42% to 100% with intraoperative hemorrhage. A second study7 looking at 52 cases between 1995 and 2003 re -ported that 8 of 52 (15%) cases experienced intraopera -tive bleeding, with all cases surviving to discharge. A more recent study5 that evaluated 285 dogs undergo -ing surgical ligation between 2008 and 2019 found an overall hemorrhage rate of 6.8%, with all cases surviv -ing surgery. Intraoperative hemorrhage occurred at the higher end of the previously reported rates at 10.8% in our study. However, the intraoperative mortality risk for dogs experiencing intraoperative hemorrhage was only 11%, which is lower than previously reported.15,17 Of dogs in this study that experienced intraoperative hemorrhage that survived surgery, 95% survived to discharge. The increased survival rate for dogs experi -encing intraoperative hemorrhage is likely attributable to recent advancements that have been made in anes -thetic monitoring and protocols, as well as increased availability of blood products in specialty hospitals.Intraoperative mortality rates have been reported as anywhere from 0% to 8%. Eyster et al15 reported an 8% intraoperative mortality rate in a review of 100 cases, and a review8 of 201 cases in 2003 reported a 7% intra -operative mortality rate. This 2003 review also showed that intraoperative complications negatively affected long-term survival.8 Other retrospective studies have re -ported intraoperative mortality rates of 0% to 2% in pro -cedures performed by experienced surgeons, defined as surgeons that have performed a minimum of 100 PDA ligation procedures.3 Results from our study were con -sistent with an intraoperative mortality rate of 2.2%, with half (56%) of the intraoperative deaths due to uncontrol -lable hemorrhage and subsequent euthanasia. The low intraoperative mortality rate was likely attributable to the improvements in anesthetic monitoring and ability to successfully treat most intraoperative complications.Our study reported 1- and 5-year survival rates of 96.4% and 87.1%, respectively, with the 1-year survival rate in this study being similar to those previously re -ported.7 The 1-year survival rate in our study was con -sistent with more recent studies and greatly improved from the 1976 review, in which the 1-year survival rate for all dogs undergoing surgery was only 34%.15 This improvement in survival over the last several decades is likely due to the significant advancements made in both detecting and treating underlying heart conditions. Screening for congenital heart defects has improved, likely resulting in dogs presenting for congenital heart disease earlier in life with less time for significant car -diac remodeling to occur. Additionally, monitoring and Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 07/22/23 07:43 AM UTC 7treatment for cardiac disease has made substantial ad -vancements in both the perioperative and postopera -tive periods, resulting in better long-term outcomes for patients undergoing surgery for a PDA.The main limitation of this study was its retrospective nature and lack of long-term follow-up for patients. Data collected relied on accurate recordings of patient history and physical examination, perioperative complications, and details provided in operative reports. The work-up for each patient was not standardized, so certain di -agnostics were not performed preoperatively in every patient. Echocardiogram reports were not available for every patient, so incomplete recordings of an LA:Ao ra -tio may have contributed to a type II error regarding the significance between an increasing LA:Ao ratio and risk of intraoperative hemorrhage. The method of measur -ing the LA:Ao ratio may not have been consistent across reports as well, so measurements may differ if a single measurement method was used. Additionally, echo -cardiogram reports did not routinely report objective information regarding the PDA, such as internal ductal diameter, degree of ductal tapering, or presence of duc -tal narrowing. Therefore, the PDA classification scheme used in this study relied on a subjective description of the shunt vessel. Finally, there is not a standardized clas -sification scheme for reporting severity of MR as trace, mild, moderate, or severe; therefore, classification of MR is subjective between cardiologists. Operative reports were evaluated to determine whether a surgery resident or board-certified surgeon performed the dissection to see if there was any correlation between surgeon experi -ence and intraoperative hemorrhage; however, this was unable to be accurately determined on the basis of avail -able information. Similarly, different methods of achiev -ing hemostasis during intraoperative hemorrhage were not mentioned in all operative reports. Postoperative recheck diagnostics were not consistently performed in every patient, and physical examination findings such as change in heart murmur were not recorded for every patient. The lack of long-term follow-up for patients was also a limitation in evaluating for associations between perioperative patient factors and complications and their effect on long-term outcome.In conclusion, surgical ligation for a left-to-right shunting PDA results in low mortality rates and excellent survival rates. Surgical ligation for a left-to-right shunt -ing PDA is thus recommended due to the good long-term prognosis. To the authors’ knowledge, this was the largest retrospective study evaluating dogs undergoing surgical ligation of a left-to-right shunting PDA. This study showed that the immediate and long-term survival rates for dogs experiencing intraoperative hemorrhage are improved compared to previous studies, and certain preoperative factors (ie, age, weight, and presence of concurrent heart disease) do not have any association with risks of intraoperative complications and therefore should not preclude surgical treatment in a patient with a left-to-right shunting PDA. While not statistically sig -nificant, the presence of an increased LA:Ao ratio may be associated with an increased risk of hemorrhage. This could be the result of an increased shunt fraction secondary to volume overload, increased difficulty of dissection around the PDA, a more friable PDA vessel, or a combination of these factors. Future prospective studies controlling for the method of LA:Ao measure -ment and evaluating the potential association between an increased LA:Ao ratio and intraoperative hemorrhage are warranted to investigate this finding.AcknowledgmentsThe authors declare that there were no conflicts of interest.Results of this study were presented at the ACVS Virtual Surgery Summit held October 7 to 9, 2021.

Answer 4

We evaluated the effect of 2 fracture reduction methodsfor the femoral MIPO applications and partially acceptedour hypotheses. Fewer fluoroscopic images were acquiredduring reduction with the FRS; however, surgical timewas longer with FRS, and there was no difference in fem-oral length or frontal, sagittal, or axial alignment afterreduction with the FRS or an IMP.Application of the FRS or an IMP resulted in near-anatomic fracture reduction in all but 1 fracture in theIMP group. We also suggest that the fracture in whichalignment was deemed suboptimal was sufficientlyaligned to yield acceptable clinical function. TheTABLE 1 Median (range) of the number of fluoroscopicimages acquired and surgical durationIMP FRS PFluoroscopic images 26 (18 –47) 7 (5 –9) .001Surgical duration (minutes) 29 (25 –50) 43 (37 –71) .011Abbreviations: FRS, 3D-printed fracture reduction system; IMP,intramedullary pin reduction.FIGURE 4 Deviation in femoral length between the virtualsurgical plan and postoperative stabilized femur. The solid barrepresents the median deviation in length for each reduction group.Abbreviations: IMP, intramedullary pin reduction; FRS, 3D-printedfracture reduction system; /uni0394, changeFIGURE 5 Change in distal frontal plane alignment fromvirtual surgical plan to postoperative alignment. Solid barrepresents the median change in frontal alignment for each group.Abbreviations: IMP, intramedullary pin reduction; FRS, 3D-printedfracture reduction system; mLDFA, mechanical lateral distalfemoral angleFIGURE 6 Change in sagittal plane alignment from virtualsurgical plan to postoperative alignment. Solid bar represents themedian change in sagittal alignment for each group. Abbreviations:IMP, intramedullary pin reduction; FRS, 3D-printed fracturereduction system; mCdDFA, mechanical caudal distal femoralangleFIGURE 7 Change in axial plane alignment from virtualsurgical plan to postoperative alignment. Solid bar represents themedian change in axial alignment for each group. Abbreviations:IMP, intramedullary pin reduction; FRS, 3D-printed fracturereduction system832 SCHEUERMANN ET AL . 1532950x, 2023, 6, alignment obtained with the FRS and IMP was similar topreviously reported results when using indirect fracturereduction techniques for MIPO.8,9,11,22In a cadavericstudy using a proprietary indirect reduction system(Synthes) or a temporary circular external fixator to alignsimulated antebrachial fractures, mean frontal and sagit-tal alignment was restored within ≤l/C14and ≤7/C14of nor-mal.22Similarly, in a small case series of antebrachialfractures using the same proprietary reduction system tofacilitate MIPO, ≤5/C14of deviation in postoperative frontaland sagittal alignment was reported.8In a clinical caseseries of 20 femoral fractures stabilized by MIPO per-formed without fluoroscopy, alignment was consideredclinically acceptable in all cases, although alignmentparameters were incompletely reported.9We partiallyascribe accurate reduction in our study to fabrication ofanatomic 3D-printed femoral models and accurate pre-contouring of plates in both reduction groups. The use ofintraoperative fluoroscopy may also have contributed tosimilarity in final alignment as intraoperative adjust-ments in reduction were permitted.Fewer intraoperative fluoroscopic images were takenduring FRS facilitated procedures. Fluoroscopy is veryuseful when performing closed intramedullary rodplacement,6,23particularly to help ensure that the pin hasbeen properly seated in the distal femoral segment. Con-sequently, more intraoperative images were obtainedduring IMP facilitated procedures. In one clinical caseseries, immediate revision surgery was required in 10% offemoral MIPO procedures performed without fluoros-copy.9When the FRS was used in our study, fluoroscopicimages were typically taken towards the end of the proce-dures to verify final implant placement and alignment.As the femur is the most common long bone fractured incats and dogs and may require greater radiation exposurefor proper image quality, the use of custom surgicalguides to facilitate alignment of these injuries may havean impact limiting ionizing radiation exposure to person-nel during MIPO.24The median duration of surgery when using the FRSwas 14 min longer than in the IMP procedures. Pro-longed surgical time in the FRS reduction group wasattributed to the multistep process required to deploy thereduction system, including the application of the cerc-lage tape and carefully fitting the drill guides to theproper location. Subjectively, the prototype suture ten-sioning system was cumbersome and we would not cur-rently recommend its use in clinical cases. Aspects ofFRS application that were inefficient included difficultypassing the FiberWire around the femur and through thesuture tensioning system. A double loop of FiberWirewas placed around the femur using a wire passer; how-ever, securing the FiberWire to the bolt and through thesuture tensioning system was relatively time consuming.To limit the difficulty placing the FiberWire, placing atoggle through the predrilled femoral holes may allow formore efficient fracture reduction, although this maynecessitate leaving the toggle on the medial aspect of thefemur. The suture tensioning system was also bulky andcould be improved with a mechanism to lock the tensioncreated during fracture reduction while placing the initialscrew in the distal fracture segment. While not includedin the surgical times, the FRS also required additionalpreoperative time, equipment, resources, and expertise todesign, fabricate and prepare the 3D-printed surgicalguides to use as drill guides.Limitations of this study include its small sample sizeand lack of an a priori power analysis. Sample size wasinfluenced by budget and time constraints and may haveresulted in type II errors, particularly between reductiongroups. Additionally, increasing the sample size may resultin greater variability in final fracture reduction and align-ment in the IMP group compared to the FRS group, as thecustom surgical reduction system theoretically reduces thesubjectivity and potential for inconsistencies in fracturereduction and realignment when using an IMP. Fracturereduction was classified as near-anatomic, acceptable, orunacceptable based on our clinical experience, as we areunaware of criteria for defining acceptable femoral frac-ture reduction. In this study, ranges for change in femorallength and alignment were used; however, using a rangeof acceptable joint orientation angles may better defineacceptable postoperative alignment. Defining acceptableand unacceptable changes in femoral alignment after frac-ture reduction and alignment warrants further research.The cadaveric nature of this study also limits the ability todirectly translate our results to clinical cases. Alternativefracture configurations, muscle contraction, and early cal-lus formation would likely make reduction more difficultwith both reduction methods. The FRS, however, wasdesigned to overcome muscle tension during fracturereduction and thus the current study design may not haverevealed the full benefits of the system. Finally, for sim-plicity, we used the ipsilateral femur for all preoperativeplanning. Clinically, however, planning from the intactcontralateral femur may be preferred. We do not believethis limitation is of major concern because we subjectivelydid not note any asymmetry in bone morphology.In conclusion, use of precontoured plates based onanatomic 3D-printed models, in conjunction with eithera custom FRS or an IMP, resulted in accurate femoralMIPO fracture reduction. Custom surgical guides andFRS was associated with less exposure to ionizing radia-tion to the surgical team and may stimulate future devel-opment of customized systems to aid in indirect fracturereduction to facilitate MIPO applications.SCHEUERMANN ET AL . 833 1532950x, 2023, 6, AUTHOR CONTRIBUTIONSScheuermann LM, DVM: Study design, data collection,statistical analysis and interpretation, and manuscriptpreparation and revision. Kim SE, BVSc, MS, DACVS-SA: Conceptualization, Study design, data collection,statistical analysis and interpretation, and manuscriptpreparation and revision. Lewis DD, DVM, DACVS:Study design, manuscript revision. Johnson MD, DVM,MVSc, DACVS-SA: manuscript revision. Biedrzycki, BSc(Hons), BVSc (Hons), MRCVS, DACVS-LA, DECVS,PhD: manuscript revision. All authors approved the finalversion of the submitted article.FUNDING INFORMATIONThis study was funded by the Edward DeBartolo Gift tothe University of Florida.CONFLICT OF INTERESTThe authors declare no conflicts of interest related to thisreport.

Answer 5

In this study we found no evidence of a significant clin-ico-pathological or clinical benefit offlushing the CBDduring cholecystectomy for the management of GBM.The rationale for flushing of the CBD is to remove mate-rial that may be contributing to ongoing cholestasis. Wefound a significant decrease over time in multiplemarkers of hepatobiliary damage and cholestasis (ALP,ALT, GGT enzyme activities, bilirubin, cholesterol), indi-cating that surgery led to an improvement in thesevalues. This is likely due to the removal of the gallbladdereliminating the reservoir of the obstructive material,resulting in improved bile flow.4Improvements in biliru-bin following cholecystectomy have been noted;18how-ever, as far as the authors are aware there has been noassessment of the effect of surgery on other hepatobiliarymarkers. Despite an improvement in parametersFIGURE 1 The effect of surgery and flushing of the CBD preoperative and postoperative on hepatobiliary markers for management ofGBM. Data shown represent mean and SEM.HERNON ET AL . 701 1532950x, 2023, 5, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.13956by Vetagro Sup Aef, Wiley Online Library on [22/07/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensefollowing surgery, there was no effect of flushing on anymeasured parameter, implying that flushing of the CBDdid not provide any further beneficial improvement incholestatic markers or clinical outcome above thatobserved with surgical cholecystectomy alone.The use of catheterization/flushing of the CBD is dis-cussed in multiple studies; however, none provides evi-dence of a benefit for its use.11,17,21,22No benefit ofcatheterization of the CBD was reported compared to nocatheterization in a recent retrospective study. Piegolset al,18identified an association of catheterization of theCBD and postoperative pancreatitis. This occurred in anumber of dogs that underwent normograde and retro-grade flushing (7/87 and 7/59 respectively). This findingwas echoed by Putterman et al,22who identified a similarnumber of cases developing postoperative pancreatitiswith normograde and retrograde flushing (8/67 and 8/50respectively). The findings of these studies provide evi-dence that it may not be the direction of catheterizationbut the manipulation of the biliary tree/pancreas thatmay be an underlying etiology for the development ofpostoperative pancreatitis.In the present study we had equal numbers of sus-pected postoperative pancreatitis in both groups, whichcould indicate that postoperative pancreatitis may beassociated with the clinical disease or from surgicalmanagement.Postoperative complications were high overall with acomplication rate of 58.1%. This was similar to previousreports with a complication rate of 50% –53.8%.19,23Regurgitation was the most common, with no differenceidentified between groups. Regurgitation has beenreported as one of the most common complications fol-lowing cholecystectomy and has been suggested to beassociated with the close proximity of the surgical field tothe pancreas leading to subsequent irritation, inappe-tence, or pain.19In this study population, regurgitationwas a cause for prolonged hospitalization.Rupture of the gallbladder was identified in 4/31(12.9%) of dogs. This is lower than in previous reports,which identified rupture of the gallbladder in 24.4% –50.0% of dogs.9,10,13The presence of peritoneal fluid waspreviously identified as an indicator of rupture of thegallbladder; however, the results from the current studyidentified low sensitivity (29%) for this.9,10,13,14The pres-ence of free fluid could be associated with reactivechanges from the presence of the GBM or from otherconcurrent diseases such as pancreatitis. Based on theresults of this study, a diagnosis of rupture of the gall-bladder based on peritoneal effusion alone should bemade with caution.The mortality rate in this study was 9.7% (3/31), whichis similar to the rate in previous studies in which an 11.7% –33.3% range was reported.1,16It has previously been shownthat elective cholecystectom ies tend to be associated with alower mortality rate.19,24All of the cases within the presentstudy underwent cholecystectomy as it was suspected theGBM was contributing to the clinical signs. In this studythere were no cases that underwent a cholecystectomy foran incidental GBM with no clinical signs.There were several limitations to the study. The hepato-biliary markers that were used were selected due to theirrole in hepatobiliary disease; however, they are not specificand can therefore be affected by other factors, i.e., drugadministration, endocrinopath ies, or renal disease. Concur-rent disease that might not have been confirmed at the timeof surgery might have affect ed the biochemical results.Diagnosis of postoperative pancreatitis was based on clinicalsuspicion rather than a comp lete diagnostic evaluation inmost cases; the number of cases with pancreatitis mighttherefore have been either overestimated or underesti-mated. The present study was a randomized controlled pro-spective study; however, the c ase numbers were relativelysmall. Larger studies would be useful to confirm the find-ings of this study.In conclusion, we found that cholestatic markersdecreased significantly 3 days postoperatively in dogsundergoing cholecystectomy for the management ofGBM but we failed to identify clinical and clinico-pathological benefit of flushing of the CBD. As therecould be risks with catheterizing/flushing of the CBD, itwould therefore seem sensible not to flush the CBD rou-tinely but only if indicated clinically.AUTHOR CONTRIBUTIONSTom Hernon: Lead author: implementation of study, dataacquisition, drafting of manuscript. Ed J. Friend: Involvedwith implementation of the study and data acquisition,reviewed manuscript and final approval for publication.Guillaume Chanoit: Involved with implementation of thestudy and data acquisition, reviewed manuscript andfinal approval for publication. Vicki Black: Provided sup-port for study design and implementation of the study,reviewed manuscript and final approval for publication.Lee Meakin: Supervisor, responsible for overall studyconcept and design, and contributing to all aspects of thestudy, reviewed manuscript and final approval forpublication.FUNDING INFORMATIONNo grant or other financial support was obtained for thisstudy.CONFLICT OF INTEREST STATEMENTThe authors declare no conflict of interest related to thisreport.702 HERNON ET AL . 1532950x, 2023, 5, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.13956 by Vetagro Sup Aef, Wiley Online Library on [22/07/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseORCIDTom L. Hernon https://orcid.org/0000-0001-7662-8601GuillaumeChanoit https://orcid.org/0000-0002-7414-6403Lee B. Meakin https://orcid.org/0000-0002-2161-9414

Answer 6

We accepted our hypotheses that there would be a high owner-reported occurrence of CCLD within this population of AKC field trial Retrievers and that there would be a lack of knowledge within the com -munity regarding CCLD.The reported occurrence of CCLD in AKC-filed trial Retrievers in our survey was approximately 12%. Though this finding was based on an owner-reported value rather than clinical analysis of medical records like previous studies, it is still much higher than the 2.8% to 4.8% looking at the national population of dogs as a whole.13 Given that the owner-reported value is so high, it indicates that there may be good reason to conduct a medical record analysis to deter -mine the validity of this value and eliminate the bias of an owner-reported value.There are studies showing a correlation with Lab -radors and CCLD-induced ligament rupture, which is consistent with our findings.7,11 The reported occur -rence of CCLD in this subset of Labrador Retrievers from our study (12%) was much higher than the 5.8% prevalence found in a previous study13 of Labrador Retrievers. Given that the previous study was con -ducted using medical records and our data were collected by owner submission, our values are not directly comparable. However, this shows the poten -tial for a vast difference between these athletic Lab -radors and a population that includes nonworking companion dogs, warranting further confirmation of this value. In addition, a recent study17 demonstrated a high rate of heritability of cruciate ligament rup -ture in Labradors, validating a genetic component to CCLD. It is reasonable to suspect that the reported occurrence in this population of Labradors is higher compared to the general population because this is a more limited genetic community. These dogs are bred for a specific purpose with a focus on certain traits, with popular pedigrees being frequently used, which can limit the genetic pool. This was reinforced, as less than half of respondents indicated that they would be less inclined to breed their dog if it had off -spring, a parent, or a sibling diagnosed with CCLD, and only a small number considered it a problem if a more distant relative of the dog was diagnosed.Even though 67% of respondents agreed that CCLD had a genetic component, it was found that 31% of CCLD-affected dogs reported in this survey had contributed offspring to the population at some point in their career. CCLD is often not diagnosed un -til later in life, so it important to note that we do not know whether these dogs were bred before or after diagnosis, as this was not reported in the survey.Another difficulty when it comes to managing CCLD within this population is the confusion sur -rounding what causes CCLD and how it is different from a traumatic CCL rupture. This confusion is high -lighted by the fact that out of the total 360 partici -pants that responded to the question on the causes of CCLD, only approximately 25% noted that CCLD is a degenerative disease that occurs over time, while close to 70% attributed the cause of CCLD to trauma. It is possible that the mixed responses are due to is -sues surrounding the terminology used to describe the disease and how it is distinct from a CCL rupture due to trauma. Moreover, the confusion may occur due to the fact that CCLD occurs slowly over time and people often misinterpret the inciting cause as trauma, as the final rupture may occur during a perceived traumatic event. In addition, other minor contributors to CCLD that are currently under inves -tigation (weight, conformation, and spay/neuter sta -tus) were not considered components of the disease by over half of the total respondents. These find -ings indicate that there is uncertainty and confusion within the community regarding what causes CCLD, which may lead to complications for the future of the sport. There is a consensus within the community that CCLD is an issue within this population, which is promising, as it opens an opportunity for educating the community on the details of CCLD and how to better manage it moving forward.Another important finding was that a larger por -tion of dogs that had 1 leg affected had not yet re -turned to the sport (75%), when compared to dogs with both legs affected (50%). Dogs that have torn 1 ligament are likely to have a contralateral ligament rupture within a year of the first tear.5 This is likely to be the case in this instance as well, and the increased rate of return to sport following treatment of dogs with bilateral tears is potentially due to different management for a single tear versus a bilateral tear. It is also possible that, because we did not receive information on the timing of the rupture compared to the return to sport, those with a single tear simply hadn’t had the same recovery time as those with a bilateral tear.Unauthenticated | Downloaded 11/03/23 05:59 AM UTC6 Our study in field trial dogs was consistent with previous studies noting age to be positively corre -lated with CCLD.8 The connection between sex and CCLD diagnosis has been noted in the past. Although not statistically significant in this study, our client-reported results remain consistent with previous findings, which indicated that altered dogs have a higher reported occurrence of CCLD than those left intact.8,17 It is unclear why sex was not significant in the present study.Limitations for this study included survey bias, as interested individuals may have been more prone to complete the survey; some questions were not able to parse out the timeline of events (eg, were animals bred before or after the CCLD diagnosis); in -ability to follow up with respondents; no access to medical records; no confirmed veterinary diagnosis of CCLD; and this survey was specific to 1 type of sporting dog. There was potential for owners, train -ers, breeders, and judges to have referenced the same dog within the survey and the same dog to be accounted for multiple times, thereby skewing the statistical results.This survey found a high owner-reported occur -rence of CCLD within the field trial community. We also confirmed that there are misconceptions being passed throughout the community surrounding the topic, lead -ing to uninformed decision-making. The results of this study can be used to educate the community on CCLD, as well as spur the interest for more research into this disease and its effects on these canine athletes. Final -ly, the results of this study should be validated with a prospective study or retrospective analysis of medical records of field trial dogs with CCLD.AcknowledgmentsThe open access fee for this manuscript was provided by the Peter J. and Freda M. Babich Fund.The authors thank Retriever News for disseminating the survey to their database.

Answer 7

We identified considerable variation in the configurationof two venous drainage vessels of the ALL, which has sig-nificant implications for surgical exploration of thisregion. Additional structures relevant to the surgicalapproach to ALL are also described in detail. The generallocation of the right pulmonary ligament has beendescribed elsewhere;1,14however, the specific attachmentconfiguration that a surgeon should be aware of was notpreviously well documented. In addition, the apex of theFIGURE 8 Left lateral thoracotomy at the sixth intercostalspace. The mediastinum has been removed to reveal the ventralprocess of the accessory lung lobe (ALL). Anatomical features:1, ventral process of ALL; 3, esophagus; 4, mediastinum; 18, medialpulmonary ligament of ALL; 19, left phrenic nerve; 20, left caudallung lobe; 21, pulmonary vein of left caudal lung lobe;22, pulmonary vein of right caudal lung lobe and ALL.1070 MATHER ET AL . 1532950x, 2023, 7, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14010by Vetagro Sup Aef, Wiley Online Library on [19/10/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseALL was found to have two “extensions ”of tissue, whichhas also not been reported previously. These areas arelikely of little anatomical sig nificance; however, in theauthors' opinion, these are relevant when considering thesafe surgical removal of this lobe, owing to the structuresthat pass within them (artery, bronchus, veins). A right lat-eral thoracotomy at the sixth intercostal space was favoredas the most feasible method of accessing the ALL for its sur-gical removal. This approach was favored due to the loca-tion of the apical structures (artery, bronchus, veins) andligamentous attachments withi nt h et h o r a x ,a sr e v e a l e db ythe dissections. Removal of the accessory lung lobe viamedian sternotomy was feasible, but not optimal. Completelobectomy via left lateral thoracotomy was not possible,although a partial lobectomy of the ventral process wastechnically feasible, this is unlikely to be clinically relevant.As per the current edition of a major veterinary anat-omy textbook “there is one pulmonary vein from each(lung) lobe, although there may be two veins that drainthe right cranial lobe ”.1There is no mention of a secondvenous drainage vessel from the ALL. Venous drainageof the accessory lung lobe was described as consisting oftwo veins —lateral and medial, which coalesced to form asingle vessel, based on an earlier anatomical study wherethe lungs of 12 dogs were injected with latex.15We alsoidentified a lateral vein (draining the dorsal process) anda medial vein (draining the ventral and right lateral pro-cesses), although in only one of nine cadavers did theycombine prior to inserting on the right caudal pulmonaryvein. No mention of any variation in the number or loca-tion of these vessels emerging from the accessory lunglobe was made in another anatomic study on right caudaland accessory lung lobes. The authors found that “theaccessory pulmonary vein always drained into the rightcaudal pulmonary vein as it emerged dorsal to the acces-sory lung lobe ”.16Consistent with this report, we alsofound that the accessory lung lobe vein(s) always drainedinto the right caudal pulmonary vein; however, theirnumber and entry point to this vessel was variable. Thevariation in the number and position of these vessels hasobvious implications for the safe surgical removal of thislobe, or surgical dissection of the area, and was a signifi-cant reason for recommending a right lateral thoracot-omy as the optimal surgical approach for lobectomy.When the lateral vein of the ALL emerged from the lat-eral aspect of the dorsal process, it was at the junction ofthe pulmonary ligament of the right caudal lung lobe,and the lateral pulmonary ligament of the ALL. Whenapproached using a right lateral thoracotomy, this vesselwas visible and accessible during transection of these lig-aments and easily ligated. However, when approachedusing a median sternotomy, this vessel was not only deepwithin the thorax and obscured by the heart and caudalvena cava, but blind transection of these ligaments wasnecessary which poses an increased risk of compromise.Recommendations in a surgical textbook are toremove the accessory lung lobe en bloc with the rightcaudal lung lobe.14Given the accumulating evidencefrom both this study, as well as previous cadaveric17andclinical case studies,11,12we propose that this does notnecessarily need to be the case. Based on the dissectionsperformed in the present study we found that an acces-sory lung lobectomy was most feasible in an ex vivo set-ting from a right lateral thoracotomy at the sixthintercostal space. Lobectomy was also achieved viamedian sternotomy; however, the visualization of theessential hilar structures was challenging given theirdepth within the thorax, limited/negligible portions out-side the parenchyma of the lobe, and the presence ofother structures which obscured them (primarily theheart and caudal vena cava).Despite published recommendations,8there remainsa paucity of evidence in the veterinary literature regard-ing the best specific open surgical approach to access theALL. A previous study investigating thoracoscopic-assisted lung lobectomies, reported that an ALL resectionperformed at the right fifth or sixth intercostal spacesresulted in a significantly shorter distance from the sta-pler anvil to the hilus of the lobe, and that pulmonary lig-ament resection was subjectively easier at the sixthintercostal space. In this study, it was not possible to per-form an accessory lung lobectomy at the seventh oreighth intercostal spaces.17Consistent with this study, wefound that a generous lateral thoracotomy incision at thesixth intercostal space provided the most reliable accessto both the hilus of the ALL and the ligamentous attach-ments which span caudodorsally from this. The presentanatomic study lacks objective criteria to completely pre-clude the use of the fifth intercostal space. However,when deciding on a specific approach, surgeons shouldbe aware that the natural curvature of the ribs has beenreported to permit more movement for the cranial ribthan the caudal rib when retracted, which in turn allowsincreased access to regions cranial to any given intercos-tal space.8The authors recommend that given the currentwidespread availability of computed tomography, anyapproach should also be based on analysis of this form ofimaging, where possible. If access to the entire thorax isrequired, then the removal of the accessory lung lobe viamedian sternotomy might be technically possible,although consideration should be given to the potentialpoor visualization of the pulmonary ligament and (vari-ably placed and numbered) venous drainage vessels,which likely to be obscured by the caudal vena cava.MATHER ET AL . 1071 1532950x, 2023, 7, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14010 by Vetagro Sup Aef, Wiley Online Library on [19/10/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseSustained cranial retraction on the heart was also neces-sary in the cadaveric setting, which could be assumed tohave implications for venous return and hence anestheticstability in the live patient.18,19This study had several limitations. A wide range ofbreeds were represented by the cadavers; however, giventhe relatively modest total number dissected, the possibilityof further anatomical variation cannot be fully excluded. Inaddition, it was not possible to draw conclusions on the rel-ative proportions of anatomic variants within the widerpopulation of dogs. The number of cadavers included wasbased on consideration of ethical concerns regarding poten-tial overuse, and previous descriptive anatomical stud-ies.15,16The freezing of cadavers in the initial phase of thestudy led to a significant deterioration in the appearanceand integrity of lung tissue, which meant that where possi-ble, cadavers were chilled and dissected within several daysof death thereafter. The results of dissections from the ini-tial cadavers were not reported in the study. The inabilityto simultaneously dissect all cadavers in a defined timeperiod favored a descriptive anatomical study, which hasthe obvious disadvantage of lacking the comparison ofobjective criteria pertaining to each surgical approach(such as distances and surgical time etc.). The ex vivonature meant that perioperative considerations such asmovement, bleeding, lung inflation, and the effect of thevarious approaches on anesth etic stability could not beevaluated. Likewise, postoperative considerations such aspain, length of hospital stay and complications could notbe evaluated. In addition, it should be noted that all surgi-cal approaches were performed in nondiseased accessorylung lobes.Upon completion of this anatomical study, we wereable to conclude that accessory lung lobectomy was mostfeasible via a right lateral thoracotomy at the sixth inter-costal space. In addition, considerable variations in thevenous drainage of the accessory lung lobe were identi-fied. Other relevant anatomical considerations were alsodescribed: the pulmonary ligament attached to the acces-sory lung lobe in a caudally pointing apex on the dorsalprocess of the lobe, and lateral and medial extensions ofthe ALL were found.AUTHOR CONTRIBUTIONSMather AJ, BVSc, MSc, MRCVS: Contributed to thedesign of the study, carried out all cadaver dissectionand photography, wrote the manuscript. Chanoit G,DEDV, PhD, DECVS, DACVS, FHEA, FRCVS: Contrib-uted to the design of the study, and provided scientific,in-line editing of the manuscript. Meakin L, MA, MRes,PhD, VetMB, DipECVS, MRCVS: Contributed to thedesign of the study, and provided scientific, in-line edit-ing of the manuscript. Friend E, BVetMed, Cert SAS,DipECVS, FRCVS: Contributed to the design of thestudy, oversaw cadaver disse ction, and provided scien-tific, in-line editing of the m anuscript. All authors pro-vided a critical review of the manuscript and endorsethe final version. All authors are aware of their respec-tive contributions and have confidence in the integrityof all contributions.ACKNOWLEDGMENTSAlice M. Harvey (of Harvey Medical Productions): Pro-duction of Figures 5A–D.FUNDING INFORMATIONThis study was supported, in part, by a grant from TheUniversity of Bristol.CONFLICT OF INTEREST STATEMENTThe authors declare no conflicts of interest related to thisreport. Funding for diagrams was provided by the Uni-versity of Bristol.INFORMED CONSENT STATEMENTCadavers were obtained from clients by informed consentspecifically for use in this study.ORCIDAlastair J. Mather https://orcid.org/0000-0003-1779-1913Guillaume Chanoit https://orcid.org/0000-0002-7414-6403Lee Meakin https://orcid.org/0000-0002-2161-9414

Answer 8

We found in this study that a client questionnaire diag-nosed SSIs with clinically useful levels of sensitivity, spec-ificity, PPV, NPV and accuracy, and that activesurveillance increased the detection of SSIs comparedto passive surveillance. Therefore, we accepted bothhypotheses.Algorithm 1 had a sensitivity and NPV of 87.1% and97%, respectively, making it useful in identifying possi-ble SSIs. However, the PPV of 69.2% was insufficientlyreliable. Algorithm 1 could be used as a “rule-out ”testto identify animals in need of further follow-up for pos-sible SSIs. Algorithm 2 had a specificity and PPV of97.9% and 86.4%, making it useful in diagnosing SSIs.However, the sensitivity of 61.3% meant a significantproportion of SSIs were missed. Algorithm 2 could beused as a “rule-in ”test to diagnose SSIs but wouldrequire manual review of “No SSI ”responses to identifyfalse negatives. Algorithm 3 had a sensitivity, specificity,PPV, NPV and accuracy of 82.6%, 97.7%, 86.4%, 97%and 95.5% respectively, making it clinically useful indiagnosing both SSIs and no-SSIs. Use of algorithm3 means manual review was only required for the 9.83%of responses associated with “Inconclusive ”results.Using algorithm 3 with manual review of “Inconclu-sive”responses, assuming all inconclusive responseswere correctly diagnosed, would combine the sensitivityand NPV of algorithm 1 with the specificity and PPVvalue of algorithm 2. In the authors' experience, “Incon-clusive ”responses often required only manual review ofthe final free text question of the questionnaire, withouttelephone or RV follow-up, to define the response into“SSI”or“No SSI ”. Hospitals wishing to create an activesurveillance system for SSIs with this client question-naire could choose an algorithm to match their require-ments and resources available.Detailed analysis of the reasons for each incorrectalgorithmic SSI diagnosis was outside the design of thisstudy. Subjective assessment of responses suggested thatclients may have forgotten SSIs, over-interpreted clinicalsigns, or misappropriated clinical signs to the wrong sur-gical procedure when multiple surgical procedures wereperformed. Surveying clients at multiple time pointscould increase sensitivity by reducing false negatives dueto forgotten SSIs, whilst educating clients on wound heal-ing expectations and signs associated with SSIs couldhelp increase specificity by reducing false positives due toover-interpretation of clinical signs.A similar questionnaire was investigated in humansurgery for post-discharge surveillance, which assignednumerical scores as cutoff points to define SSIs.23Itreported similar sensitivity and specificity for individualscores as algorithms 1 and 2 in the current study.FIGURE 1 Flow diagrams depicting the method of surgical site infection definition from client questionnaires using algorithm1, algorithm 2 and algorithm 3. SSI, surgical site infection.188 GLENN ET AL . 1532950x, 2024, 1, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14011 by Cochrane France, Wiley Online Library on [05/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseClient questionnaires were completed for 37.9% moresurgical procedures than RV questionnaires. This sug-gests that clients may be more motivated or available toprovide post-discharge surveillance so surveilling themcould increase the response rate, and thereforesensitivity, of an active surveillance system compared toRV surveillance alone.This study differed from previous examples ofactive surveillance by (i) using a questionnaire with aclient-specific definition of SSI, and (ii) definingTotal surgical proceduresn = 754Eligible surgical procedures n = 691Eligible surgical procedures with a gold standard diagnosisn = 366Eligible surgical procedures with a gold standard diagnosis and complete client questionnairen = 173Excluded within 30/90 days ( n = 6)Excluded(n = 325)Excludedquestionnaire ( n = 193)Eligible surgical procedures with a completed client questionnairen = 294Excludedquestionnaire ( n = 382)early (n = 15)Excluded(n = 121)Included Excluded Included ExcludednnFIGURE 2 Flow diagram illustrating study enrollment and exclusion. Gold standard diagnoses were made by a veterinarian accordingto Centers for Disease Control and Prevention (CDC) criteria.21n, number.TABLE 2 Comparison of algorithm surgical site infection diagnoses from client questionnaires to gold standard diagnoses.Algorithm defining SSI True positive True negative False positive False negativeAlgorithm 1 27 130 12 4Algorithm 2 19 139 3 12Algorithm 3 19 130 3 4Note: Results for algorithm 3 excluded 17 “Inconclusive ”results.Abbreviation: SSI, surgical site infection.TABLE 3 Descriptive statistics of algorithm surgical site infection diagnoses from client questionnaires compared to gold standarddiagnoses.Algorithmdefining SSISensitivity(95% CL)Specificity(95% CL) PPV (95% CL) NPV (95% CL)Accuracy(95% CL)Algorithm 1 87.1% (82.1 –92.1) 91.5% (87.4 –95.7) 69.2% (62.4 –76.1) 97% (94.5 –99.6) 90.8% (86.4 –95.1)Algorithm 2 61.3% (54 –68.5) 97.9% (95.7 –100) 86.4% (81.2 –91.5) 92.1% (88 –96.1) 91.3% (87.1 –95.5)Algorithm 3 82.6% (77 –88.3) 97.7% (95.5 –100) 86.4% (81.2 –91.5) 97% (94.5 –99.6) 95.5% (92.4 –98.6)Abbreviations: CL, confidence limit; NPV, negative predictive value; PPV, positive predictive value; SSI, surgical site infection.GLENN ET AL . 189 1532950x, 2024, 1, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14011 by Cochrane France, Wiley Online Library on [05/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensequestionnaire sensitivity, specificity, predictive valuesand accuracy.3–5,11,24,25,30 –35This methodology allowedquestionnaire distribution and data collection to be auto-mated through existing practice management softwareand online questionnaire platforms, and data analysis tobe automated through algorithms encoded as formulaeinto a spreadsheet. This process minimizes the cost andtime requirement compared to telephone surveillance ormanually reviewed questionnaires and maximizesresponse rate compared to RV surveillance alone. Theauthors' institution now uses this automated method tocontinuously actively surveil SSIs.Passive surveillance failed to detect 19.4% of SSIs in thisstudy. Although this was lower than the 27.8% –35% previ-ously reported,3,4it underestimated the SSI rate by 24%and shows the importance of active surveillance. Activesurveillance has been shown to reduce the incidence ofSSIs,36–38a n dw h e nc o m b i n e dw i t ha ne f f e c t i v ei n f e c t i o ncontrol program was shown to reduce SSIs by 40.5% inhuman hospitals.10With the rise of multidrug resistantSSIs,15the importance of SSI prevention is paramount.Active surveillance of SSIs in veterinary surgery couldreduce the incidence of SSIs and therefore should play animportant role in hospital infection control programs.The overall SSI rate of 8.22% using active surveillancewas within the 2.83% –12.9% range reported by other stud-ies evaluating multiple surgical procedures, as was the SSIrate of each surgical wound classification.3–5,11,24,25,30 –35Comparing SSI rates between hospitals and studies isdifficult due to different caseloads, SSI definitions, dura-tions of follow-up, and surveillance methods. Manystudies used an SSI definition of 14 days or less whichlikely reduced their sensitivity.11,24,35 –38In the presentstudy, 11/57 (19.3%) SSIs would have been missed withthis definition. Standardization of SSI definitions andthe use of risk-adjusted SSI rates have beenrecommended.14,17,39The use of this questionnaire-based method would allow comparison of SSI ratesbetween institutions.This study had several limitations, including theincomplete response rate. It was possible there couldhave been a reporting bias, where clients were more orless likely to respond if their animal had an SSI. How-ever, the 44.7% response rate was comparable to otherquestionnaires in the veterinary literature.34,40 –43Patientswho died before follow-up were excluded from contactfor active surveillance due to ethical concerns about caus-ing unnecessary distress to clients. SSIs within this groupwere still recorded by passive surveillance, but it was pos-sible some were missed due to the lack of active surveil-lance. The gold standard diagnoses partially relied onreferring veterinarian assessment of wounds and diagno-sis of SSI. Even with a uniform SSI definition, there issome subjectivity in the interpretation of wounds mean-ing that false positive and false negative gold standarddiagnoses could have occurred.Surgical procedures involving implants were followed up90 days postoperatively in this study. This was based uponCenters for Disease Control and Prevention (CDC)guidelines,17but means some implant-related SSIs thatdeveloped clinical signs after 90 days could have beenmissed. Studies on SSIs followi ng veterinary orthopedic sur-gery found that SSIs were detected within a median of 18 –21 days,25,44and that 75% –100% of SSIs were detected within90 days.25,34,44Only two SSIs were known to have occurredafter 90 days in our study and were detected by passive sur-veillance. This suggests that the majority of implant-relatedSSIs were detected with the 90-day surveillance.As deep or implant-related SSIs can have few externalclinical signs, these could have been undetected by thequestionnaire because all algorithms required a “woundhealing problem ”to be considered for SSI diagnosis. ThisTABLE 4 Number and incidence of SSIs for each surgical wound category.28Wound category Number of surgical procedures Number of SSIs SSI rate Use of implantsClean 426 34 7.98% Implant =187No implant =239Clean-contaminated 204 12 5.88% Implant =3No implant =201Contaminated 30 3 10% Implant =6No implant =24Dirty 94 13 13.8% Implant =5No implant =89Total 754 62 8.22% Implant =201No implant =553Abbreviation: SSIs, surgical site infection.190 GLENN ET AL . 1532950x, 2024, 1, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14011 by Cochrane France, Wiley Online Library on [05/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licenseformat was chosen to make the questionnaire quick tocomplete to increase the response rate but may haveresulted in reduced sensitivity to SSIs not associatedwith superficial wound healing problems (e.g., deepinfections). An 8 –12 week postoperative radiographicfollow-up of patients that underwent orthopedic surgerieswas routinely performed during the study period, there-fore we believe deep SSIs in this cohort would likely havebeen detected by passive surveillance of hospital records.Together, these limitations mean the SSI rate reported waslikely still an underestimation of the true SSI burden.This questionnaire could not be used to identify thetype of SSI (superficial, deep, organ space). Whilethe additional free text information provided by clients insome cases was sufficient to suggest the type of SSI,the accuracy was not assessed. We believe this differentia-tion is likely beyond the capability of client woundassessment.In conclusion, this questionnaire was able to diagnoseSSIs from client responses for dogs and cats that under-went soft tissue or orthopedic surgery, with clinically use-ful sensitivity, specificity, predictive values and accuracy.Active surveillance increased the detection of SSIs com-pared to passive surveillance. This client questionnairecould be used to create an active surveillance system forSSIs with automated distribution, data collection andsemi-automated analysis, reducing barriers to implemen-tation. Further research is warranted to evaluate itsimpact on SSI rate.AUTHOR CONTRIBUTIONSGlenn OJ, BVMS, MRCVS, AFHEA: Conception, design,data collection, data analysis, manuscript preparation,manuscript review. Faux I, BVMS, MRCVS, AFHEA:Conception, design, data collection, manuscript review.Pratschke KM, MVB MVM MScClinOnc CertSASDipECVS FRCVS: Conception, design, manuscriptreview. Bowlt Blacklock, KL, BVM&S DipECVS SFHEAPGCert PhD FRCVS: Conception, design, manuscriptreview.FUNDING INFORMATIONNo funding was used or awarded for this research.CONFLICT OF INTEREST STATEMENTThe authors declare no conflicts of interest related to thisreport.ORCIDOwen J. Glennhttps://orcid.org/0000-0001-5930-5376Kelly L. Bowlt Blacklock https://orcid.org/0000-0001-6482-7224

Answer 9

The present case series described the applica -tion of 2 different barrier membranes to repair hard palate defects. There was an 80% complete success rate (4 of 5 dogs) when a barrier membrane was used in addition to traditional techniques for repair of very wide congenital hard palate defects. Further -more, clinical signs resolved in all dogs despite small defects that remained in 2 dogs (functional success; Supplementary Table S1).Common areas of ONF formation after CFP re -pair in humans are the transition of the hard and soft palate and the junction of the premaxilla and max -illa.11 The same areas also were affected in dogs in past studies1,3,6,8 as well as the present case series. In children, the prevalence of ONF after previous CFP repair had been as high as 35%, but more recent studies lowered that rate of ONF to 7% to 13% with traditional techniques.25 The reported prevalence of ONF after previous CFP repair in client-owned dogs is 50%.6 Risk factors associated with ONF formation in humans are closure of the soft and hard palate in 2 stages (soft palate first, hard palate later), the op -erator’s experience, the patient’s age, and severity of the CFP.18,25–27 In dogs, only age (> 8 months old at the time of first repair) was associated with ONF for -mation. Despite the relatively high rate of ONF for -mation, the outcome of CFP repair in dogs usually is successful because clinical signs may not be present if the ONF is small and located rostrally. Factors as -Figure 4 —Harvesting auricular cartilage graft in a dog (case 1). A—The U-shaped cutaneous incision at the caudal surface of the pinna of the ear is adapted to the size of the cartilage needed for the palate defect repair. B—The cartilage is exposed after blunt and sharp dissection; the central auricular artery is preserved and remains attached to the skin flap, continuing to the apex of the ear (arrow). C—A ruler is used to determine the size of the graft and the location of the incision in the cartilage. D—The cartilage is secured with stay sutures to avoid manipulation with forceps; elevation from the dorsal cutaneous aspect is made with a periosteal elevator or the back of a scalpel blade, avoiding perforation of the skin. E—Pinna after harvesting of the cartilage graft; necrosis of the apex of the pinna occurs if the auricular artery (arrow) is damaged. F—The harvested cartilage graft before being trimmed to adapt to the desired shape and size.Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 12/24/23 09:43 AM UTC 7sociated with unsuccessful outcome are dog weight (< 1 kg) and multiple previous surgical attempts at repairing the ONF.6 The impact of the operator’s ex -perience on successful outcome of palate defect sur -gery in dogs has never been investigated. However, it is important to mention that most of these pro -cedures described in the veterinary literature were performed by board-certified veterinary dentists or oral surgeons with special skills and years of expe -rience. Although many factors may have influenced the healing of a palate defect (size of the defect, vas -cularity of surrounding tissue, etc), it is worth men -tion that the dogs with only functional success in the present case series were the first ones having the barrier membrane surgery performed.Placing auricular cartilage between the nasal and oral mucosal layers in children required only minimal tissue dissection and reduced the incidence of ONF formation.18 Auricular cartilage has also been used to treat oronasal and oroantral fistulae in people as well as in experimental companion animals.13,16–19,21,23,28 Cartilage grafts have minimal vascularity and are resistant to infection.17–19 They are not rejected be -cause of being harvested from the same individual. They are recommended for closure of ONF smaller than 10 mm2 or 10 mm in diameter.12,19Palatoplasty in children with interpositional ADM from human cadavers has been reported since 2003. Acellular dermal matrix is recommended in congeni -tal CFP repair for defects wider than 10 to 15 mm if excessive tension at the surgical site is to be ex -pected, the anterior alveolar cleft is wide, and the quality of the surrounding oral mucosa is poor. For recurrent ONF, some oral surgeons suggest using ADM in defects > 5 mm or < 10 mm or in the pres -ence of tension.20,29The use of a barrier membrane for the repair of congenital defects of the hard palate and ONF re -maining after CFP repair in the present case series study suggests several benefits. The hard palate de -fects could be repaired during one anesthetic ses -sion without the need of prior tooth extractions and staging of the procedures to incorporate labial and buccal mucosal flaps in the repair. This decreased the patient’s morbidity and reduced the number of anesthetic procedures. The patient kept func -tional teeth. Because a simpler surgical technique was used (medially positioned vs overlapping flaps) with less area of denuded bone having to heal by granulation and epithelialization, overall recovery occurred relatively faster.Barrier membranes provided an additional layer. Double- or triple-layer closures are recommended because they decrease the tension at the suture line during breathing and increase the resistance of tis -sues to trauma caused by tongue movement and mastication.8,11 Both auricular cartilage and fascia lata provide a surface where connective tissue and epithelium can migrate and heal by second intention, which is beneficial in the presence of small areas of dehiscence due to compromised vascularity. If a ped -icle flap is used, the blood supply to the most rostral aspect of the flap may be affected due to the de -tachment from the rostral gingiva and ligation of the major palatine artery a few millimeters caudal to the rostral edge of the flap. Furthermore, tissue contrac -tion during healing may cause retraction and tension at the suture line in an area that is poorly vascular -ized. Special attention should be paid to obtaining adequate coverage of the membrane with mucosa between the incisor teeth and incisive papilla.In the 2 congenital cleft lip and palate clefts of the present case series, the use of the barrier mem -brane allowed repair of the alveolar cleft and most rostral hard palate defect in 1 surgery. Without the membrane, the 2-flap palatoplasty might have par -tially failed, with lateral defects potentially remain -ing at the level of the canine teeth. Despite the mem -brane being exposed to the oral cavity laterally, the oral mucosa healed without complications, and no signs of infection were noticed.Conchal cartilage grafts have been used since the 1990s. An experimental study28 in rabbits ob -tained full closure of ONF in 96% of them. In humans, the success rate varied between 54% and 79%, but the studies are not comparable to each other, as differ -ent methodologies were employed in each one.11,12,15 It was suggested that the use of a cartilage graft in recurrent small ONF (< 1 cm) is a safe procedure. For larger ONF, this method could be used due to its sim -plicity, and another more complex procedure could be chosen in case of failure. ONF treated multiple times before using the cartilage graft failed more frequently than those where the graft was used af -ter the first ONF recurrence (33% vs 7.1%).11 In that study, the nasal and oral mucosa were sutured to the graft placed in between these 2 layers. The oral mucosa had lateral releasing incisions.11 The other studies left part of the cartilage graft exposed to the nasal and oral cavity when mucosal apposition was not possible.12,15Progressive resorption of the cartilage graft and substitution by fibrous and granulation tissue, pro -viding a bed for growth of epithelium over the graft surface, were shown to occur in an experimental study with rabbits. Resorption started in the center of the graft as early as 3 weeks, and there was no lon -ger cartilage visible in the histological specimens at 16 weeks.28 Multiple studies30–33 have shown resorp -tion of the cartilage graft if it lacks perichondrium, is severely traumatized, or is covered by fascia or oxi -dized regenerated cellulose. The resorption rate may be different in dogs, as the cartilage graft was visible under the remaining defect in case 5 of the present case series at the 6-month recheck examination. Ex -cept for a case report in a dog and a small case series in cats, all other reports13,22,23,34,35 in small animals used additional oral mucosal or mucoperiosteal flaps to completely cover the defect and the graft.Potential causes of an unsuccessful outcome with the surgical technique described here include infection, using a barrier membrane that is too small for the defect, insufficient coverage of the membrane by mucosa or mucoperiosteum (eg, not enough pocketing when creating the envelope flap), and dislodgment of the membrane due to suture Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 12/24/23 09:43 AM UTC8 failure.23,28 For both the auricular cartilage and fascia lata grafts in the present case series, the membrane periphery was covered by oral mucosa for at least 5 mm in all directions, but in most cases, it reached 1 cm in all directions (instead of the 2 to 3 mm report -ed in previous studies).13,21,23 This greater membrane coverage also provided better support for the flaps. However, there is more graft material in contact with connective tissue that may induce inflammation, act as a foreign body despite being biocompatible,24 or increase the risk of infection. Insufficient coverage of the membrane under mucosa at the incisive papilla could have been the reason for failure in case 3.Whether the barrier membrane in the present case series became integrated in surrounding tis -sue or simply acted as a temporary barrier to allow healing of oral and nasal mucosa prior to being re -sorbed could not be determined in this clinical study. Histologic evaluation of the repaired palate would elucidate this, but this type of investigation likely would raise ethical concerns, could jeopardize the successful outcome obtained, and would not be pos -sible before the patient’s death and its body being made available for necropsy. In case 6 of the present case series, the cartilage could be palpated with a periodontal probe and visualized through the ONF at the last (6-month) follow-up examination (Supple -mentary Table S1). There are some disadvantages associated with the use of an auricular cartilage graft, involving the preparation of another surgical site and additional anesthesia and surgery time. The cartilage harvested was large enough to cause cos -metic changes at the donor site. Necrosis of the skin of the pinna may occur if the central auricular artery is damaged. Necrosis of the implanted cartilage also is a possibility before the surgical site has completely healed. Based on this limited case series, the authors prefer closing the palate defect with mucoperiosteal flaps and leaving the membrane only exposed in ar -eas where there is bone support (lateral incisions) to heal by second intention. The authors’ current pref -erence is to use a fascia lata membrane instead of the auricular graft to avoid a second surgery site and shorten the anesthesia time.The techniques described here are not appli -cable to all palate defects, and many factors should be considered before utilizing a barrier membrane, including size of the soft tissue and bone defect, tissue available next to the defect, age of the pa -tient, deciduous and permanent dentition present (erupted and not yet erupted) in and near the de -fect as well as in areas of potential flaps creation, the operator’s skills, and type, size, and quality of the membrane available. Furthermore, other surgi -cal techniques could have been chosen (in particu -lar for the dogs with congenital palate defects) that likely would have provided a successful outcome for the greater part of the palate. But based on the authors’ previous experiences, there was concern about ONF formation caudal to the incisive papilla (cases 3 to 5) due to a severe bony defect (> 50% of the palate width) in that area. In areas of poor tissue vascularity as a result of multiple failed at -tempts at repair, using a barrier tucked under pock -ets of an envelope flap may be a better option than complete defect and membrane coverage with lo -cal pedicle flaps because less iatrogenic trauma is exerted.13 An allogenic membrane may not always cover a large palate defect between the maxillary quadrants if the patient is a fully grown large-breed dog. Auricular cartilage is autologous, thicker, and usually larger (depending on the breed), potentially providing a better outcome for the repair of more extensive hard palate defects and in those exposed to increased trauma from swallowing or mastication.The principles of palate surgery apply regard -less of whether a barrier membrane is used. They include gentle tissue handling, preservation of tis -sue vascularity, avoidance of tension at the suture line, suturing of fresh soft tissue edges, avoidance of tissue-damaging tools (eg, electrocautery to control hemostasis), not suturing over a void, and wound closure in at least 2 layers.3 Airflow through the na -sal cavity/nasopharynx may cause increased tension at the suture line. The addition of the membrane re -duces stress in the soft tissue. In the event of tissue breakdown or suture failure in areas with poor vas -cularity, it could provide a bed for second intention healing. The membrane also allowed for the repair of congenital hard palate defects during only 1 anes -thetic session.The lack of CT imaging is a limitation of this case series. A head CT would characterize the palate de -fect and other congenital abnormalities.2,36 The au -thors routinely use CT for acquired palate defects, but it is selected case by case in congenital orofa -cial clefts. In the authors’ experience, oral examina -tion with palpation of the palate is more critical for surgical planning than CT. However, CT would add more information regarding the size of the bony defect in relation to the soft tissue defect. Preop -erative clinical signs resolved in all cases after the procedure; the follow-up may have been too short to evaluate chronic changes. Long-term monitoring is recommended, as concurrent nasal cavity malfor -mation (underdevelopment of the nasal turbinates)3 or possible traumatic injury of the palate (ie, due to impacted hair in the oral mucosa from grooming or playful behavior with hard objects) may lead to chronic rhinitis and ONF.In this case series, the use of barrier membranes was described to repair congenital hard palate de -fects and ONF remaining after previous CFP repair. In the dogs with congenital hard palate defects, the number of anesthetic sessions could be decreased by not having to stage the procedures. The tech -nique described may decrease the risk of wound dehiscence compared to other surgical methods and avoids extraction of teeth to gain mucosal tis -sue for making larger flaps. The application of a bar -rier membrane in ONF after previous CFP repair was relatively easy, avoided excessive soft tissue manipu -lation, and covered a larger bone defect area. This case series shows that this technique is a safe and well-tolerated alternative repair option for palate defects in dogs, but further studies with more cases Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 12/24/23 09:43 AM UTC 9and a control group (without membrane) are war -ranted to justify this technique routinely.AcknowledgmentsNone reported.DisclosuresThe authors have nothing to disclose. No AI-assisted technologies were used in the generation of this manuscript.FundingThe authors have nothing to disclose.

Answer 10

In dogs undergoing staphylectomy for BOAS surgery abilateral preoperative maxillary nerve block containingadrenaline in addition to lidocaine results in significantlylower intraoperative hemorrhage, accepting our initialhypothesis.In dogs a successfully performed maxillary nerveblock provides anti-nociception, attenuates the sympa-thetic response to surgery and reduced the need forintraoperative fentanyl and injectable anesthetictop-ups.12,21The maxillary nerve does not affect motorinnervation of the soft palate, therefore blocking of thisnerve should not affect the ability of the dog to controlthe upper airways postoperatively,12and should be bene-ficial to reduce pain in the postoperative period.Vasoconstrictors, such as adrenaline, infiltrated intothe pterygopalatine fossa act by causing vasospasm of themaxillary artery, decreasing the amount of blood flow tothe soft palate and nasal mucosa, therefore reducinghemorrhage in human patients.16Prior to the presentstudy, there have been no studies in dogs illustrating thisfact. Adrenaline also delays the absorption of local anes-thetic drugs and prolongs their efficacy, so has beenadded to peripheral local anesthetic nerve blocks for overa century.22A predominant β-receptor response occursafter subcutaneous or intramuscular injection of adrena-line in combination with a local anesthetic, meaning thelocal anesthetic absorption time will be increased due toFIGURE 3 Surgeon hemorrhage score for groups adrenaline(A) and no-adrenaline (NA). Mean values are connected by dashedline, median by solid line. English bulldogs are identified by blacksymbols. Data are horizontally jittered to aid clarity.FIGURE 2 Total hemorrhage and normalized hemorrhage for groups adrenaline (A) and no-adrenaline (NA). Mean values areconnected by dashed line, median by solid line. English bulldogs are identified by black symbols. Data are horizontally jittered to aid clarity.WILLIAMS ET AL . 71 1532950x, 2024, 1, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14039 by Cochrane France, Wiley Online Library on [05/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensethe local vasoconstrictor effect. The degree and durationof this β-receptor response is directly related to theamount of adrenaline injected.22,23The prolonged analge-sic effect of the addition of adrenaline was not examinedin this study but is another potentially useful benefit.Adrenaline also causes increases in salivary excretions,24which may have caused an increase in the weight of theswabs and cotton-tipped applicators in group A. Thismeans that hemorrhage could have been even lower thandescribed in group A.The addition of adrenaline to a bilateral maxillarynerve block, at the concentration used in the presentstudy, appeared to be safe with no significant adverseeffects noted, such as hemodynamic instability. Thisagrees with other studies in dogs and human patientswhere adrenaline was administered in combination witha local anesthetic both in neuraxial blockades andepidurals.22,25 –27Vnuk et al. did report that the additionof adrenaline to an epidural resulted in a significantincrease in cardiac output and heart rate compared tobaseline, but this was associated with a positive effect ofpreventing hypotension.25Reduced hemorrhage improves the visual surgicalfield to allow for more accurate suture placement andcorrect apposition of the oropharyngeal and nasopha-ryngeal mucosa to reduce incisional dehiscence.28Inaddition to the objective measures of total hemorrhageand normalized hemorrhage, the semi-quantitative mea-sure of surgeon hemorrhage score was also significantlydifferent, with dogs in group A having a lower score,meaning surgeons considered the visibility to be greater(Figure3).Reduced hemorrhage also prevents unnecessaryblood loss, reduces the risk of aspiration of blood and theformation of clots in the nasal cavity prior to other proce-dures, such as correction of stenotic nares, which is com-monly performed following staphylectomy.9,16,18Thedifference in median hemorrhage between the two treat-ment groups was 6.13 g or 5.78 mL, which the authorsdeem to be a clinically significant volume. Hemorrhage isalso likely to increase surgical time, due to multiple stopsfor suctioning or swabbing, although this was not investi-gated in this study.A sharp cut and sew staphylectomy was used for allcases in this study to ensure that surgical technique didnot affect total hemorrhage. However, it seems logicalthat the addition of adrenaline would also reduce hemor-rhage for other sharp techniques such as the folded flappalatoplasty as described by Finji and Dupré.29As thishas proven to be effective, and considering the wideapplication in human surgery, these results lend them-selves to form the basis for further investigations forother oral surgical procedures.Some outliers were noted in group A, who experi-enced a greater hemorrhage volume, despite receivingadrenaline (Figure2). This could possibly be explainedby an inaccurate maxillary nerve block being performed.As with other peripheral nerve blocks, if the drugs arenot injected in close proximity to the nerve, the effective-ness of the block can be reduced, especially when theblock is performed in a blind manner, as in this study.The intraoral approach is routinely employed in our insti-tution, as the landmarks are of easy localization, there isno need for clipping the dog's hair and the approach hasbeen found to be significantly more accurate than thepercutaneous approach.20Another approach may havebeen to infiltrate the entire local area (alone the line ofsurgical excision for example), as is reported in humanpatients undergoing palate surgery,30and this methodmay prove to be more consistent due to the greater areaof block coverage.English bulldogs were found to have greater totalhemorrhage. Analysis of normalized hemorrhage stillsuggested a breed effect after accounting for bodyweight.It is possible that the volume of lidocaine and adrenalineused in this study was inadequate for the larger pterygo-palatine foramen of the English bulldogs compared withthe pterygopalatine fossa of smaller breeds. An improve-ment would be to calculate the required volume of localanesthetic and adrenaline in mL/kg, to ensure an effica-cious volume is used. Since there were only eight Englishbulldogs in the current investigation, further study toconfirm or refute this finding would be justified. The pro-portion of English bulldogs in each of the treatmentgroups was not statistically different.Limitations of this study include: a small samplesize, although this was adequate on power analysis,which assumed at least a 25% reduction in hemorrhageand in fact this study achieved a 77.1% reduction inmedian total hemorrhage between group A and groupNA. Although we found no complications relating to theaddition of adrenaline, it is probable that a far greaternumber of cases would be required to confirm or refutethis. Another limitation is that different surgeons withvarying tissue handling and speed of performing theprocedure were included, which could influencehemorrhage.It is possible that not all the hemorrhage was col-lected on the surgical swabs and cotton tipped applicatorsto be weighed. This potential loss was minimized by plac-ing a surgical swab behind the soft palate at the entranceof the larynx to collect any hemorrhage pooling caudallyand minimizing aspiration of blood. A surgical assistantwas also used to help apply the cotton tipped applicatorsto the cut surface and collect any hemorrhage, thereforeminimizing the time that the surgeon would have taken72 WILLIAMS ET AL . 1532950x, 2024, 1, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14039 by Cochrane France, Wiley Online Library on [05/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licenseto put down instruments and apply the applicators. How-ever, the same surgical assistant was not used for everyprocedure. It was still possible that some hemorrhagethat was not absorbed occurred and if this was the case,due to the study design, it would be expected that thisloss would have been distributed equally between thegroups. However, this is an area of the study where somevariability inevitably exists.Anesthetic, analgesic and gastroprotection drugs werenot standardized between groups and were at the surgeonand anesthesiologist's discretion. As these drugs caninfluence salivary production,31,32this could have influ-enced the weight of the cotton-tipped applicators and istherefore a limitation of the study.Another limitation is that coagulation testing was notperformed on dogs prior to surgery, however, no dogshad clinical signs or history suggestive of a coagulopathyand if excessive hemorrhage occurred, electrocauterycould be used as a rescue protocol and the patient with-drawn from the study.In conclusion, this study has demonstrated a reduc-tion in intraoperative hemo rrhage when adrenaline isused in combination with a lo cal anesthetic as part of amaxillary nerve block. The fact that we observed nocomplications relating to adrenaline administrationmeans the use of a combined adrenaline/lidocainedrug for maxillary nerve blocks in BOAS patients issafe and recommended, as the reduction in hemor-rhage is likely to have an intraoperative beneficialeffect.AUTHOR CONTRIBUTIONSWilliams PJ, BVSc, PGCertSAS, MRCVS: Study design,data acquisition, analysis and interpretation; manuscriptdrafting and revisions; final version approval. DeGennaro C, DVM, DipECVAA, EBVS, MRCVS: Studydesign, data acquisition, manuscript revision, final ver-sion approval. Demetriou JL, BVetMed, CertSAS,DipECVS, FRCVS: Study design, data acquisition, manu-script revision, final version approval.ACKNOWLEDGMENTSThe authors would like to thank Tim H. Sparks, GradIS,PgCert, MSc, MSc, PhD for his statistical support andhelp with figure preparation.CONFLICT OF INTEREST STATEMENTThe authors declare no conflicts of interest related to thisreport.ORCIDPhillipa J. Williamshttps://orcid.org/0000-0002-8332-8807

Answer 11

In this small cohort of dogs, BSSLA resulted in a low perioperative complication rate and favorable out -comes. These findings are in accordance with a previous study5 on outcomes following bilateral adrenalectomy (single session or staged) via open celiotomy. Appro -priate case selection is of critical importance when in -dications for BSSLA are being determined. In the dogs of this study, BSSLA was only performed when modest-sized tumors with no vascular invasion were found, in accordance with the criteria proposed by Mayhew et al6 for unilateral laparoscopic adrenalectomy.Due to the perioperative risks and mortality asso -ciated with adrenalectomy, appropriate preoperative endocrinological interrogation and preoperative ther -apy are recommended, as previously reported.8,10,11 Phenoxybenzamine, an adrenergic α-receptor block -ing agent, is used to manage hypertension associ -ated with pheochromocytomas.8,10,11 Preoperative administration of phenoxybenzamine is shown to in -crease survival in dogs undergoing adrenalectomy for pheochromocytomas.8,10,11 In this cohort of dogs, 4 of 6 received phenoxybenzamine prior to surgery. Al -though only 1 of 6 had histopathology consistent with pheochromocytoma, pretreatment with phenoxyben -zamine was likely administered due to preoperative hypertension or the inability to definitively rule out pheochromocytoma prior to surgery. Minimal altera -tions in blood pressure were noted in the operative period in this cohort of dogs and may have been a re -sult of pretreatment with phenoxybenzamine or, more likely, based on histopathological evaluation, due to the benign origin of the vast majority of adrenal tu -mors removed from the dogs in this study.In the dogs of this report, a standard 3- or 4-port technique was used to perform unilateral laparoscopic adrenalectomy in lateral recumbency as previously described,2,6,7 and then the dog was repositioned into contralateral recumbency, and laparoscopic adrenalec -tomy was repeated on the opposite side. The need for repositioning of the dog and repeating aseptic surgi -cal preparation along with introduction of portals pro -longed anesthesia time. Mean surgical time for BSSLA in the dogs of this study (158 minutes total/79 min -utes per side) was similar and lower than 2 previous re -ports2,6 of unilateral laparoscopic adrenalectomy that found median surgical times of 69.8 and 90 minutes, respectively. A laparoscopic approach that does not require repositioning of the dog and allows for access to both adrenal glands would be desirable to minimize anesthesia time in cases of bilateral adrenal tumors.Overall, the peri- and postoperative complica -tion rates for the dogs included in this report were low, and the frequency and type of complications encountered in this report are consistent with previ -ous reports2,6 of unilateral adrenalectomy. Inadver -tent diaphragm perforation during adrenal gland dis -section was suspected in the dog that developed an intraoperative pneumothorax. This complication has not been reported in open adrenalectomy, and thus the risk is likely higher in laparoscopic procedures; however, the overall risk is low. The longer anesthe -sia time required for BSSLA did not result in a higher incidence of anesthetic complications in this study; however, the sample size in this study is limited. Fur -ther studies would be required to determine whether complication rates for BSSLA compare to unilateral laparoscopic adrenalectomy and to further support single-session procedures over staged procedures.Postoperative outcomes for the dogs included in the study were excellent. At the time of last fol -low-up, none of the dogs that successfully under -went BSSLA had known recurrence or significant complications related to their procedures. One dog is known to have been euthanized for an unrelated cause, and the remainder were known to be alive at the time of last follow-up. No complications as -sociated with the procedure or difficulties managing postoperative Addison disease were reported in this cohort of dogs.In human medicine, bilateral adrenalectomy is most often considered a treatment option for hy -peradrenocorticism that is refractory to medical management.12 Due to the significantly longer ex -pected life span in humans when compared with ca -nines, bilateral adrenalectomy is often considered as a last resort due to the need for lifelong miner -alocorticoid. One study11 comparing open versus laparoscopic single-session, bilateral adrenalecto -my in humans found that BSSLA had longer surgi -cal times but shorter postoperative hospital stays when compared with open procedures. Thus, high-risk anesthetic candidates may benefit from staged procedures.11 Based on the findings of this study, we suspect that laparoscopic bilateral adrenalec -tomy may have similar advantages and disadvan -tages in canine patients; however, further studies are needed.Limitations of this study were the retrospec -tive nature and small number of dogs undergoing BSSLA. Anesthetic case management and periop -erative case management were variable between cases, and therefore, low-grade complications may be underreported. Additionally, no dogs in this report underwent successful BSSLA for bilateral adrenal medullary tumors (pheochromocytoma); therefore, further studies are needed to determine whether the findings of this report hold true for this tumor type.AcknowledgmentsThis work was neither sponsored nor funded in part or full. The authors have nothing to declare.The authors thank Drs. Ryan Appleby and Alexa Bersenas.Unauthenticated | Downloaded 10/08/23 06:32 AM UTC 5

Answer 12

Malocclusion can occur because of differences in jaw length and/or width, malalignment of the teeth or a combination of these issues,1 and it is associated with significant morbidity, requiring treatment.9This study was conducted to evaluate malocclusion of the premolars and molars through morphometric meas-urements to understand which specific features lead to malocclusion. Theoretically, the traumatic impingement of the third and fourth maxillary teeth in the periodon -tium of the mandibular teeth could be caused by several factors, either isolated or combined: palatoversion of the reduction of maxillary premolars of the maxilla; bucco-version of the mandibular premolars and molars; or skeletal anomalies in the absence of dental deviations, such as deviation of normal anysognatism.CBCT was used to perform the morphometric meas -urements since it is superior in the assessment of bone height and teeth details.10 Although radiography was performed during diagnosis and treatment, these imaging modalities were not used to assess morpho-metry parameters, as standard two-dimensional radi-ography can lead to distortion and overlapping of the structures.11,12In this retrospective case–control study, cases and controls were selected based on data from retrospective dental records. This approach could have led to bias, as only animals with dental disease were included and they were different from the general population. However, malocclusions are developmental problems, and many dental diseases, such as dental trauma or periodontal diseases, are acquired. Animals that do not manifest the anomaly (ie, pre-molar/molar malocclusion) would be suitable candidates for assessment in the control group, as they are potential healthy animals, without any devel -opmental anomalies. At the same time, for this study, it was necessary for the animals in the control group to Figure 4 Palatal impingement in a cat with malocclusion as an additional finding: (a) clinical appearance of impingement; (b) periodontal probe inserted into impingement; and (c) coronal slice in cone-beam CT showing osteolysis of the palatal process of maxillary bone bilaterally (blue arrowheads)Figure 5 Receiver operating characteristic curves of the skull index (green) and facial index (blue) for discriminating between the presence and absence of caudal teeth malocclusion8 Journal of Feline Medicine and Surgery have undergone CBCT. The increase in the ratio of con -trols to cases (2:1 ratio) in this study helped increase the statistical power of the findings. Regardless of the efforts to reduce confounding factors and increase homogeneity in both groups by matching age and sex, there was an over-representation of brachycephalic cats in the cases group that could not be matched in the same proportion in the control group. This was an important limitation that must be acknowledged, since it may impact some results. Indeed, it was very difficult to find control indi -viduals with brachycephalic conformations and that were free of malocclusions.The cats in the cases group had a significantly higher body weight than those in the control group. Weight-related differences could have resulted from incident or differences in breed types, as BSH and Maine Coons were predominant in the cases group (n = 19) when compared with those in the control group (n = 10).Skull and facial indexes were assessed to evaluate the presence of possible skeletal malocclusions, and distances between the crown tips and angulations evaluated dental malocclusions to identify the presence of a frequent pat -tern of malocclusion. The results suggest that both skeletal and dental discrepancies contribute to traumatic maloc -clusion in the caudal teeth. Undoubtedly, brachycephaly is a significant contributor to malocclusion, as skull and facial indexes were significantly different between the groups. Furthermore, both skull and facial indexes were good predictors of the occurrence of traumatic malocclu -sion in the caudal teeth. This study proposes 0.7331 as the cut-off for the skull index and 0.196 for the facial index. Brachycephaly is a cranial dysmorphology strongly linked to similar genetic disarrangements encountered in some forms of craniosynostoses in humans.13 As the skull and facial indexes increase, the risk of occurrence of malocclusion in the caudal teeth is high. These cut-off values can be used by breeders to select phenotypes with less severe malocclusions.The results also suggest that dental malocclusions are a strong contributing factor to the occurrence of trau-matic malocclusion, as maxillomandibular spaces and angulations were significantly different between the groups. As axial distances in cats carrying this malocclu-sion were significantly higher in group A but consistent, the angulation of the third and fourth maxillary pre-molars was significantly more acute in this group. The cats in this group present maxillary premolar angula-tions, which favour the impingement in the mandibular tissues, as the angulations contribute to a reduction in the maxillomandibular dental space. This study theo-rises that such cats have a wider maxilla but at a more angulated position, at the expense of the angulation of the palatine bone. This finding is also supported by the observations reported here, as our study showed bone resorption in the medial aspect of the maxillary teeth in the palatal process of the maxilla. This anomaly seems to result from traumatic malocclusions of the molar man -dibular teeth to the palate and palatine process of the maxillary bone.The relationship between malocclusion and trauma to the periodontal tissues has been widely described in human dentistry.14–16 However, some studies have reported the lack of an association between malocclusion and progression of periodontal lesions.17Periodontal injury is one of the consequences of severe malocclusion in humans, affecting quality of life. The associated pathological conditions of this injury include gingival surface injury, reduction of alveolar bone density and clinical attachment loss.18 All these problems were identified in the cases group. The most severe grade of malocclusion in the present study resulted in the devel -opment of pyogranuloma. This pathology has been described in studies of humans but with a lack of asso -ciation with occlusal trauma.19ConclusionsTraumatic malocclusion in the mandibular soft tissue is related to both skeletal and dental malocclusions. Brachycephaly is a significant feature contributing to the increase in caudal teeth malocclusions. Skull and facial indexes could serve as a discriminative predictor of den -tal anomalies. The cephalometric cut-off values reported in this study can serve as an important tool for the com -munity of cat breeders in the selection of cats for breeding.Acknowledgements The authors would like to thank the veterinary nurses who were members of the research team: Joanna Warzecha, Natalia Huc ´ko-Pietka and Justyna Matusin ´ska.

Answer 13

This study identified that SBCs were a diagnostic imagingfeature of canine OA and that the number of SBCs pre-sent and their size were predictive of radiographic OAseverity. The complete absence of SBCs in normal elbowswithout radiographic signs of OA further supports theview that they are a pathognomonic feature of canine OAas they are in human OA. This study also identified thatthe number of SBCs were proportionate to the radio-graphic severity of their OA and were not an independentfeature of age. They also had a predilection for thehumeral joint surface.As far as the authors are aware, this is the first timethat the relationship between increasing number of SBCsand radiographic OA severity has been reported in canineOA. The literature for SBCs in dogs is limited but thepresence of SBCs with human OA is well established,with the number and size of SBCs also increasing withOA severity.32,39,40The longer established relationshipbetween SBCs and OA in humans probably relates toFIGURE 2 Bar chart representing the distribution ofradiographic osteoarthritis (OA) severity (based on the largestosteophyte) between the young ( ≤2 years old, n=36 elbows) andold (>2 years old, n=40 elbows) Labrador retrievers.FIGURE 3 (A) Box-and-whisker plot of the total number of subchondral bone cysts (SBCs) identified per elbow ( n=76) separated byradiographic osteoarthritis (OA) severity (based on the largest osteophyte). (B) Box-and-whisker plot of the size (maximum diameter) ofSBCs for each OA grade (total of 640 SBCs).JONES ET AL . 345 1532950x, 2024, 2, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14047 by Cochrane France, Wiley Online Library on [14/02/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licenserelative size of human joints and the different types ofimaging used to evaluate them, including magneticresonance imaging (MRI).34,41Subchondral bone cystsare not readily identified on plain radiographs of thecanine elbow, and this is likely due in part to their sizeand the superimposition of the component bones of theelbow. With the introduction of CT and planar analysisat ever increasing resolution, SBCs were readily visiblein the dog.Although SBCs have been poorly described in dogswith spontaneous OA, they have been documented inexperimental canine OA models using MRI,28,42specifi-cally the Pond –Nuki model. These studies identified that,following transection of the cranial cruciate ligament,SBCs developed within the stifle as early as 2 weeks fol-lowing destabilization, with all dogs in one study havingSBCs at 12 weeks.28,42These studies also identified thatSBCs had a predilection for the medial tibial plateau.28,42Direct comparison with these results is limited due to thedifferent subtype of OA between these studies andthe results reported here as well as imaging modalitiesused. However, these studies support our data in findingthat SBCs are present in early radiographic OA, althoughthe exact temporal relationship is unclear and requiresfurther investigation, ideally a longitudinal study. Never-theless, their presence in all dogs with any measurableradiographic OA in our study indicates that they may bea useful marker of radiographic elbow OA, particularly inthe early stages.The tendency for increasing SBC size in relation toOA severity has been well documented in humans, withtheir total, maximum, and average volumes all being pos-itively correlated with worsening OA.32The relationshipbetween increasing SBC size (as measured by their maxi-mum diameter) and radiographic OA severity is seen inthis study and highlights that SBCs are dynamic andchange as radiographic OA severity worsens, principallygetting larger. This dynamic nature of SBCs has beenconfirmed in longitudinal studies using MRI in humanOA, with several reports identifying that SBCs can growas well as regress.40,43,44The exact mechanism that gov-erns SBC size is unknown; however, studies using quanti-tative CT identified a positive correlation with increasingbone mineral density and SBC volume.32Changes in thesubchondral architecture have already been implicatedwith the development of SBCs as a close relationshipbetween SBC number and subchondral bone sclerosishas been identified using high-resolution peripheralquantitative CT (HR-pQCT).45Potentially, SBC size couldbe intricately linked to changing environment in the sub-chondral bone, similar to the SBC number.Aging is also considered to have important effects onsubchondral bone remodeling in dogs with an increase inbone density with age.46Given the potential relationshipbetween subchondral sclerosis and the SBC number, it issurprising, that despite a high prevalence of severe radio-graphic OA in the older cohort in this study, age was notfound to be a significant factor with the SBC number asexpected ( p=.805), likely due to the relatively rapidonset of severe radiographic OA in elbow dysplastic dogs.This is similar to the findings in human femoral heads,for which neither SBC number nor volume was corre-lated with age.47There was, however, an observed age-dependent increase in cyst diameter with an increasedlikelihood of larger SBCs with older dogs. It is possiblethat the age-related changes in subchondral bone micro-architecture mentioned above facilitate the expansion ofthese cysts in OA joints. Alternatively, in these olderaffected dogs, these SBCs may be coalescing, creatinglarger cysts. These findings, nonetheless, indicate thatalthough the formation of SBCs is not necessarily a fea-ture of advancing age, their expansion may be agerelated.An observation in this study was the tendency forSBCs to form within the medial compartment of theelbow. This medial compartment is a common site forarticular cartilage degeneration with OA in the dysplasticelbow and this is commonly termed medial compartmentdisease.9,48It is thought that eccentric loading patternscaused by elbow dysplasia exacerbate these cartilage andsubchondral bone changes,48leading to regionalizedOA. This has been highlighted during an artificial load-ing study of canine cadaveric elbows where the proximalulnar articular surface was shown to contribute a signifi-cant proportion of load transfer in the elbow joint.49Ithas also been demonstrated that more extensive remodel-ing with OA occurs in the medial aspect of the elbow, inparticular around the medial coronoid process.9More-over, in a case report where an SBC in a dysplastic canineelbow was identified with CT, it was localized to themedial trochlear notch.29This would suggest that themedial compartment is a predisposed site for more severeOA change, and hence SBC formation.There were several limitations to this study. First,SBCs were identified purely on the basis of imaging find-ings and were not confirmed histologically. Moreover,some of these SBCs were at the limits of the resolutionavailable with clinical CT imaging with a voxel size of0.181/C20.181/C20.5 mm, meaning that there could be amargin of error with the measurements of the smallerSBCs ’diameters. Furthermore, the complex 3D shape ofSBCs means that their largest diameter measurement canbe challenging. Further studies could mitigate this withthe use of HR-pQCT or ex vivo imaging with micro-CTby providing volumetric measurements. Micro-CT or HR-pQCT analysis would also have assisted in examining346 JONES ET AL . 1532950x, 2024, 2, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14047 by Cochrane France, Wiley Online Library on [14/02/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensepericystic architectural changes in subchondral bone,which could better contextualize the findings of thisstudy; however, it is not currently possible to accommo-date a canine limb within the scanning field. Moreover, itwould be useful to examine these changes in a widercohort of dogs including other breeds, as well as over alongitudinal period to establish the temporal relationshipwith SBC development and OA. The OA subtypeincluded in this study is also exclusively secondary toelbow dysplasia and did not include other types of OAsuch as post-traumatic or primary OA. Furthermore,although there is a clear relationship between SBCs andradiographic canine OA presence and severity, we areunable to comment on whether they are predictive ofclinical lameness or other clinical examination findings.It is well established that other radiographic features ofOA do not always correlate with the clinical presenta-tion;50however, further research would be required todetermine if SBCs are also nonpredictive. In this study,OA was defined on the presence of osteophytosis, andradiographic OA severity was based on the size of thelargest osteophyte. This method has been used in severalother publications, and the grades of osteophytes formpart of OA grading systems in humans,33but it is possiblethat this method of grading of OA severity may not cap-ture fully the true disease status of the joint. It is alsoworth noting, that while osteophytosis is a cardinal radio-graphic hallmark of OA, they have been identified in thehuman vertebral column as a general indicator of aging,although it is difficult to fully isolate ageing from OA.51In conclusion, this study has demonstrated that SBCsare a recognized radiographic hallmark of osteoarthritisin canine elbows. In particular, it found that SBCs wereabsent in elbows without any other radiographic signs ofOA, and that they became more numerous in osteoar-thritic elbows as radiographic OA severity increased. Fur-thermore, their size (maximum diameter) increased incases of severe radiographic osteoarthritis. These findingsprovide a valuable basis for investigations into the clini-cal relevance of subchondral bone cysts in dogs, toimprove current diagnostic and therapeutic frameworksfor the treatment of canine osteoarthritis.ACKNOWLEDGMENTSAuthor Contributions: Jones GMC, BSc, BVetMed:Contributed to the design of the study, identified suitablecases, collected and interpreted the data, drafted, andrevised the manuscript. Gosby MR, BSc, BVetMed: Iden-tified suitable cases, collected and interpreted the data.May EM, BSc, BVetMed: identified suitable cases, col-lected and interpreted the data. Meeson RL, MA, VetMB,PhD, MVetMed, Diplomate ECVS, FRCVS: Contributedto concept development, the design of the study,interpreted data and revised the manuscript. All authorsprovided a critical review of the manuscript and endorsethe final version. All authors are aware of their respectivecontributions and have confidence in the integrity of allcontributions.Statistical support for this work was kindly providedby Yi-Mei Ruby Chan, BSc, MSc, PhD, CSTAT, charteredstatistician and associate professor in statistics.CONFLICT OF INTEREST STATEMENTThe authors declare that the research was conducted inthe absence of any commercial or financial relationshipsthat could be construed as a potential conflict of interest.DATA AVAILABILITY STATEMENTThe data collected in this trial are collated and stored atthe Royal Veterinary College in London (RVC) and areavailable from the corresponding author upon reasonablerequest.ORCIDGareth M. C. Joneshttps://orcid.org/0000-0001-9519-7720Richard L. Meeson https://orcid.org/0000-0002-8972-7067

Answer 14

Intraluminal leak pressure testing is a well-recognizedand commonly used technique to compare intestinalintegrity following experimental closure or anastomosis.The methodology used in the present study replicatesprevious studies with similar aims; the pressure testingdevice was easily constructed using accessible mate-rials.11Sutured enterotomies reinforced with cyanoacry-late were able to withstand a significantly higher ILP incadaveric jejunum, compared to enterotomies closed withsuture alone or surgical sealant alone. The MIPs werecomparable in the suture only (HSE) and suture and cya-noacrylate (HS +CE) groups. The ILP reported for theHSE group in this study were in line with previous litera-ture looking at ex vivo cadaveric leakage pressures insutured enterotomies and the above study found that theaddition of surgical sealant increased the ILP beyondthose previously published.11Physiological small intesti-nal intraluminal pressures of live, unanesthetized dogsare reported to range from 15 to 25 mmHg.9However,recent research using wireless motility capsule technol-ogy reports a higher intraluminal contraction pressure inthe small intestine with a mean of 34 mmHg in the con-scious dog with a significant reduction in pressures whenanesthetized.10Both the HSE and HS +CE groups pro-duced supraphysiological ILPs compared to published lit-erature and the CE did not and consequently, would notbe recommended as a closure technique for an enterot-omy. The MIP did not significantly differ between groupswhich again, appears to be in line with published litera-ture. The suture holes along the enterotomy accountedfor 60% of the ILL in the HSE group in the above studywhich is a lower percentage than that previously pub-lished for sutured enterotomies in chilled cadaveric sam-ples, whereby 100% of the leakage was from the sutureholes.11In the HS +CE group, only 40% of samplesleaked from the suture holes and most samples insteadleaked from the suture line. The authors hypothesize thatthis difference in ILL is due to the cyanoacrylate “plug-ging ”the suture holes when in the viscous state at thetime of application, essentially waterproofing that area,and reducing the leakage seen from the needle holes.Although the waterproofing properties of synthetic seal-ants have previously been reported, their ability to alsocreate an airtight seal has only recently been demon-strated in canine cadavers, following partial lunglobectomies.23,24As the suture continues to be the key-stone in holding the incision together, this suggestionmay explain the difference in the leakage location for theHS+CE group.Decreasing the risk of intestinal leakage and dehis-cence is pertinent to a good clinical outcome in compan-ion animal practice. Intestinal dehiscence is welldocumented but not fully understood. Dehiscence isoften seen at day 3 –5 after surgery and is presumed to beassociated with the lag phase of healing where thestrength of the site is reduced by approximately 85% com-pared to immediately postoperatively.25Risk factorsreported to be associated with dehiscence include hypo-tension, hypoalbuminemia, septic peritonitis at the timeof surgery, inflammatory bowel disease and the presenceof foreign material in the intestinal tract.6–8,26Reinforce-ment of enterotomy sites with additional procedures andbiological tissue using techniques such as serosal patch-ing and omental wrapping is favorable in apparentlycompromised intestine or in patients which are higherrisk for dehiscence, as they have been shown to increasethe construct leakage pressure.27Oversewing is anotherreinforcement technique that has been shown to be effec-tive in reducing the incidence of postoperative dehiscencefollowing gastrointestinal surgery in dogs.28Experimentalstudies demonstrate that oversewing successfullyincreases leakage pressures following stapled gastrointes-tinal anastomoses; however, the authors believe that thesize of the canine small intestine limits the ability to per-form oversewing techniques following a simple enterot-omy.29,30The fact that oversewing did increase leakagepressures experimentally and this has then been associ-ated with a reduction in the incidence of intestinal dehis-cence clinically, supports the general theory thatinterventions, such as cyanoacrylate, which increasesleakage pressures experimentally may result in a reduc-tion in dehiscence and leakage clinically. A similar exper-imental study did not find a significant difference inleakage pressures when stapled gastrointestinal anasto-moses were oversewn with a Cushing pattern; however,the combination did yield the highest leak pressures fromthe constructs tested.31It is important to note that dehis-cence occurring within the first 24 h of surgery typicallyreflects technical error, such as failure of the suture toengage with the submucosa or intestinal necrosis and inthis circumstance reinforcement techniques may be inef-fective.26Jones et al. (2017) investigated the use of a bio-polymer adhesive in combination with suture forenterotomy in caprine cadavers. The application of seal-ant following routine enterotomy closure was not onlyshown to be feasible and technically easy but was alsoshown to significantly increase the intraluminal leakagepressures of the intestinal segments.32This is congruent372 THOMPSON ET AL . 1532950x, 2024, 2, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14059 by Cochrane France, Wiley Online Library on [14/02/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensewith the findings of this study, that reinforcement ofenterotomies with a synthetic cyanoacrylate surgical seal-ant increases the initial leak pressures.Cyanoacrylates polymerize when they meet moistureforming a strong bond between tissues and making themresistant to the flow of most liquids and air. They alsohave high antibacterial properties which makes themappealing for the use in gastrointestinal surgery and dueto their strong adhesive properties only small quantitiesof sealant are often needed to create a watertight bar-rier.23,33In 2009, a group compared closure of smallintestinal enterotomies by double layer suture or syn-thetic sealant in 10 dogs and reported no intestinal leak-age, a shorter procedural length, and a lowermacrophage response with the sealant, concluding it wasan effective enterotomy closure technique.34Syntheticsealants have also been assessed as a closure techniquefollowing partial resection of the caecum in laboratoryrats with micro- and macroscopic histological findingsand postoperative outcomes supporting the use of seal-ants in cecal surgery.35The addition of biological sealantsto canine cadaveric enterectomies also significantlyincreased experimental leakage pressures; however, bio-logical sealants are inherently more expensive and arenot licensed for veterinary use globally which limits theclinical applicability of this study.36In the human field,Kotzampassi and Eleftheriadis (2015) used sealants in themanagement of intestinal anastomotic leakage followinggastrointestinal surgery in people for over 25 years.Within that period, the authors describe its use in63 patients with a clinical and technical success rate of96.8%; glue application was concluded to be a valuableclinical tool, and its use avoided reoperation in the studypopulation and had no negative effects.37The use ofBioglue (CryoLife Europa Ltd, Hampshire, UnitedKingdom) in the attenuation of post-thoracotomy alveo-lar leaks was evaluated and its use was found to be asso-ciated with a shorter duration of air leakage and shorteroverall hospitalization, further showcasing its sealantproperties.38Another study demonstrates the hemostaticproperties of cyanoacrylates during laparoscopic partialnephrectomies.39Interestingly, Nandakumar et al.40report that surgical adhesives were successful in reinfor-cing both intact and defective stapled gastrojejunostomieswhich begs the question as to whether surgical sealantcould also be effective in reinforcing defective or incom-plete sutured gastrointestinal closure.In vitro studies using cell cultures have shown mildformaldehyde production because of the hydrolytic deg-radation of the alkyl chains of the sealant. This isreported to accumulate within the tissues and promotean inflammatory response. As a result, cyanoacrylateshave not been readily utilized or accepted for use inintracorporeal surgery in veterinary medicine. However,in vivo studies are ongoing, and results are showing noevidence of cytotoxicity and moreover show that cyanoac-rylates have good tissue integration, effective short-termbiocompatibility, and a low macrophage response in ani-mal and human subjects.16There are also increasingreports of the use of cyanoacrylate in vascular surgery orin the treatment of fistulae, varices, and ocular conditionswithin human medicine.41–44Evidence promotes theiruse in dentistry and oral surgery, with closure of intraoralmucosal incisions being deemed easier and faster withsynthetic sealants when compared to sutures, with equiv-alent overall outcome.45Veterinary publications reviewtheir use in urogenital surgery with successful cystotomyclosures seen in porcine models, supported by an experi-mental study evaluating bladder closure in canines,showing a faster, effective closure.46,47Despite research showing no difference between leak-age pressures after enterotomy closure when comparingin vitro and ex vivo models, limitations inherently includethe ex vivo nature of the study.48Additionally, the ex vivodesign means that information pertaining to any possibleinflammatory responses and consequent short- or long-term side effects remains unknown. Another limitation ofthe study was the use of cadaveric intestine which is likelyto behave differently to live or diseased tissue. In anattempt to limit the impact of this, the authors chilled andstored the cadaveric tissue as per Duffy et al.11who foundno difference between pressure testing in chilled and freshcadaveric samples. All sutured enterotomies were per-formed by a single residency-trained surgeon to allow foruniformity across samples; however, there was likely sub-tle variability which cannot be accounted for.To the best of the authors knowledge, no previousstudies have looked at the effect of cyanoacrylate aug-mentation of canine enterotomies with leakage pressures.The results of this study show that the mean ILP for theHS+CE was significantly higher than the HSE, andboth were superior to the CE alone. Both the HSEand HS +CE groups withstood pressures that would beexpected clinically, and the CE group did not. For thisreason, the authors would not recommend using cyano-acrylate only to close enterotomies. Although the authorsdo not believe cyanoacrylate should replace suture forenterotomy closure, these results suggest that under clini-cal conditions, synthetic sealants may have the potentialto decrease postoperative intestinal leakage or dehiscencewhich could subsequently reduce the incidence of associ-ated patient morbidity and mortality. The authors pro-pose that the use of cyanoacrylate would likely be mostappropriate in circumstances where patients are deemedhigh risk for postoperative dehiscence. The conclusionsof this study set the foundations for further researchTHOMPSON ET AL . 373 1532950x, 2024, 2, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14059 by Cochrane France, Wiley Online Library on [14/02/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licenseexploring the clinical safety of surgical sealant enterot-omy reinforcement with in vitro models and investigatingthe consequent impact on postoperative leakage.AUTHOR CONTRIBUTIONSThompson JL, BVM&S, MRCVS, FHEA: Participated inthe conception of this study, literature review and writingand editing of the manuscript. Miller L, BVSc: Partici-pated in the equipment construction and data collection.Bowlt Blacklock K, BVM&S, DipECVS, SFHEA, PGCert,PhD, FRCVS: Participated in the conception of the studyand critical review of the manuscript.FUNDING INFORMATIONNo monetary funding or grants were received to aid com-pletion of this study; however, the surgical sealant hand-pieces (LiquiBand®Fix8™) were provided by AdvancedMedical Solutions Group Ltd.CONFLICT OF INTEREST STATEMENTAll authors declare no conflicts of interest relate to thisstudy. All authors contributed equally to this study.ORCIDJamie-Leigh Thompsonhttps://orcid.org/0000-0002-6634-7926Kelly Bowlt Blacklock https://orcid.org/0000-0001-6482-7224

Answer 15

This study documents the surgical outcomes of a large cohort of dogs that underwent unilateral LA for resection of adrenal masses at 7 centers with con -siderable experience in veterinary minimally invasive procedures. Morbidity and mortality associated with LA compared favorably with reported outcomes of previous studies documenting the outcomes of OA performed through a celiotomy. Perioperative mor -tality for OA for treatment of noninvasive masses has been documented in the 3% to 25% range.5,10–15 Perioperative morbidity is much harder to compare with historical controls, as reporting mechanisms vary so widely between studies and not all studies categorize data for noninvasive and invasive tumors separately. Care must always be taken in the inter -pretation of data from different studies, as a variety of biases, including variable case populations and surgeon experience levels, can affect outcomes and interpretation. In this study, 99% of dogs survived the surgical procedure, and 95% of dogs survived the perioperative procedure and were discharged from the hospital. Perioperative complication rates were also relatively low in this case population. Major hemorrhage was the most common intraoperative complication, occurring in 5.5% of cases, with dam -age to the ipsilateral renal vein being reported more frequently compared with other large blood vessels in the area. In 4 of 5 dogs in which major hemorrhage emanated from iatrogenic damage to either the renal vein or artery, a caudal pole tumor or a tumor effac -ing the entire gland was being operated on. Great care needs to be taken with tumors that affect the caudal pole, as their capsule can be closely adher -ent or compressing the renal vein and artery, and these masses may represent a population at higher risk for major hemorrhage. Preoperative CECT pro -vides an excellent tool for anatomical assessment of the margins of the tumor and can aid in good case selection, especially for less experienced surgeons early in their experience curve. Suspected throm -boembolism and pancreatitis were both uncommon postoperative complications reported or suspected in 3.2% and 2.3% of dogs, respectively. Antemortem diagnosis of these conditions is, however, notorious -ly challenging, so it is possible that the incidence of these complications was underestimated.One of the principal tenets of good technique in surgical oncology is preservation of the tumor cap -sule to prevent spillage of tumor cells and a potential increase in the incidence of local recurrence. The au -thors believe that the issue of capsular penetration has been highlighted in LA because of the excellent visualization of the surgical field that is afforded by the magnification the telescope provides. This hy -pothesis is given some credibility by the fact that few reports of OA mention capsular damage, although it almost certainly occurs with some regularity when OA is performed. In the first publication of LA by the author’s group (some cases of which are also in -cluded in this study), a comparison between LA and OA in 2 smaller cohorts of dogs undergoing LA sug -gested a higher incidence of capsular penetration in the LA group, although it was pointed out that in most of the cohort of dogs undergoing OA, a de -tailed account of whether capsular penetration had occurred was lacking.3 In the first-ever publication of LA in the veterinary literature,1 capsular penetration was performed proactively after the authors noted the often delicate tumor capsule and necrotic cen -ter that make adrenal tumors very prone to rupture. Until this point, the clinical significance of capsular penetration had been uncertain. In the study of the present report , capsular penetration occurred in 19% of cases and was found to be a significant risk factor for recurrence. Dogs where capsular penetration oc -curred during dissection experienced 6.5 times the recurrence rate of dogs where capsular penetration didn’t occur. This finding supports the recommenda -tion that every attempt should be made to prevent capsular penetration by using delicate tissue dissec -tion and avoiding the direct grasping of the adrenal tumor or tumor capsule during the procedure. It is important to note, however, that even in the popula -tion of dogs in which capsular penetration occurred, only 27% experienced recurrence, and none of these dogs were reoperated on. It is possible, however, that a lack of uniform follow-up with diagnostic imaging may have underestimated the incidence of recurrent local disease in this cohort.A variety of factors were shown to have a sig -nificant effect on conversion rate for LA in this study. Increasing BCS increased conversion rate. This is an interesting finding that is mirrored in the human sur -gical literature, where body mass index has a signifi -cant effect on conversion also.16,17 The adrenal gland often sits in a large fat pad cranial to the cranial pole of the kidney, and dissection of this fat pad is neces -sary to enable resection. When this fat pad is more pronounced, as presumably happens in dogs with a higher BCS, the dissection and visualization of tissue planes can be more challenging, leading to surgeon frustration and perhaps hastening the decision to convert by some surgeons. This hypothesis is backed up by the observation that loss of visualization was Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 12/11/23 09:46 AM UTC 7the second most common cause for conversion in the 9.4% of dogs that were converted from LA to OA. When performing LA in dogs with high BCS, strate -gies for overcoming fat pad–related challenges such as aspiration of fat with a suction-irrigation probe or the use of extra instrument ports for placement of retractors might help mitigate these issues in some patients. Interestingly in humans, where higher mor -bidity and conversion have been reported for LA in obese patients, it has also been pointed out that LA should not be avoided in the overweight or obese co -hort, as it is these very patients that might stand to benefit the most from the many advantages a mini -mally invasive approach provides.18 Other factors associated with increasing conversion rate included lesion size and surgeon experience level. Increasing lesion size is a well-known risk factor for conversion, which also increases conversion risk in humans.16,17 As lesions increase in size, visualization tends to become obscured, especially in smaller dogs. Neo -vascularization tends to be greater in larger tumors, and hemorrhage from the tumor capsule and sur -rounding tissues can be profound. Larger tumors may also increase the risk of major hemorrhage from surrounding large vessels due to displacement or compression of these structures, making identifica -tion and avoidance more challenging. In this study, for every 1-cm increase in mass diameter, the risk of conversion to an open approach increased by a fac -tor of 1.6. There is no known cutoff for lesion size where the risk of conversion or intraoperative com -plications becomes unacceptably high, so every sur -geon has to decide case selection criteria for them -selves. The primary author considers maximal mass diameter of around 5 to 6 cm to be the upper limit for cases that will be attempted laparoscopically in dogs, but again this is a personal choice and will vary from surgeon to surgeon.The effect of surgeon experience on outcomes of procedures can be challenging to study in smaller cohorts of patients. In this study, data from a large cohort of canine patients were available, and dogs were operated on by surgeons with widely differing experience levels (median number of LA performed per surgeon was 9, with a range of 1 to 61). The analy -sis of surgical experience could have been performed in several ways, but we elected to analyze outcomes data from those surgeons who had performed < 10 cases and compare it with those who had performed 10 or more. Ten LA procedures represented the mid -point of experience, as 8 surgeons had performed < 10 and 8 had performed ≥ 10 LA procedures. Great -er surgeon experience with the procedure was shown to decrease surgical time, conversion rate, and risk of death prior to discharge. Operating time and conver -sion rate have also been shown to decrease in hu -mans as surgeon experience increases.19 In 1 study in humans,20 the learning curve for transperitoneal LA has been evaluated in relation to surgical time us -ing the cumulative sum method. In that study, the authors identified 3 general phases of the learning curve, with phase 1 (learning period) involving the first 34 procedures, phase 2 (acquiring competence phase) involving procedures 35 to 51, and finally phase 3 (mastering phase) involving procedures af -ter the 52nd case, where operating time started to decrease. Where the plateau occurs after which vet -erinary surgeons would enter their mastering phase for operating time and conversion rate for canine LA would likely be difficult to calculate for the patient cohort in this study given that only 3 surgeons in this study had performed > 34 LA procedures and only 1 surgeon had performed > 52. These analyses could also have been biased by a variety of factors, includ -ing different surgeons’ criteria for case selection, the quality of surgical equipment available to them, the level of experienced mentorship available, surgeons’ personal tolerance for extended surgical times, or the logistical challenges at different institutions that might make conversion to an open approach a more rapidly reached surgical decision in dogs compared with human patients.There are a variety of limitations to this study. As with all retrospective studies, certain elements of the medical history were incomplete for some cases, and variation between case management protocols at different institutions in different countries cannot be easily accounted for with this study design. For assessment of the effect of surgeon experience, cas -es contributed by surgeons who had performed > 10 cases also included case data from the first 10 cas -es that those more experienced surgeons had per -formed, and this was not accounted for in the statis -tical model design. The authors could have excluded the more experienced surgeons’ first 10 cases, but this would have significantly reduced the size of the case cohort available for evaluation and possibly in -creased the possibility of a type II error.In conclusion, results of this study demonstrated, using data from a large cohort of dogs undergoing LA, that resection of unilateral adrenal masses with -out caval invasion is associated with low periopera -tive morbidity and mortality. The study has further -more provided tools for surgeons and pet owners to aid in stratifying risk to make better case selection decisions for their pets in the future.AcknowledgmentsThe authors declare that there were no conflicts of interest.

Answer 16

The aim of the current study was to compare the accu-racy of radial osteotomies performed using 3D PSGs ver-sus the previous standard FH approach in normal ex vivocanine radii. It was hypothesized that 3D guide usewould improve osteotomy angle and location accuracy.This hypothesis was partially supported for the simplefrontal plane wedge and the most complex single oblique(inclined) plane osteotomy but not for oblique planeosteotomies. Using an acceptable osteotomy angle toler-ance of 5/C14,3it was found that 84% of 3DP guided osteo-tomies were within this range, in comparison of 50% ofFH osteotomies.Three-dimensional printed guides provided improvedangle accuracy but this comparison with freehand was nodifferent in the sagittal plane for both wedge groups.Guided osteotomy accuracy was consistent in all planesand typically within 5/C14of the targets. This is consistentwith recent clinical case series of guided radial osteo-tomies in dogs with deformity.3Freehand performancewas more variable, with greater accuracy in group 2 as awhole and in the sagittal plane for groups 1 and 2. Intrao-perative clinical assessment and alignment of a saw tothis plane may be easier to execute although this has notbeen investigated specifically. Improvement in freehandperformance may also be related to increasing surgeonskill with sequential performance of the osteotomies(group 1, group 2, group 3). All osteotomies were per-formed by a surgical resident under the guidance of aboard-certified surgeon. The resident had no prior clini-cal experience with corrective osteotomies other thancompletion of a practice osteotomy session on 2 limbpairs prior to this project. Right and left limbs were ran-domized for treatment but we could have considered ran-domizing group order too. Furthermore, the sameindividual who performed the 3D virtual planning andguide design conducted the subsequent surgical osteo-tomies. This preoperative planning process likelyimproved the outcomes overall but in particular for thefreehand group. Despite these comments, improvementwas not sustained in group 3; however, freehand orienta-tion and execution of a single oblique plane osteotomy isconsidered very technically challenging.12,13Causes for deviation from the virtual target may varybetween groups. The location of the osteotomy was gen-erally accurate in all groups, typically within 3 mm.There was greater variation in the angles of the osteot-omy planes. We did not account for the kerf of the sawblade (0.3 mm) during the assessment, which may have asmall effect on our data. In 3D-guided cases, error mayarise from imprecise guide placement on the bone, sur-geon technical error such as bending of the oscillatingsaw blade away from guide shelves or slot, or flex of theguide material. In FH cases, surgeon technical error inmeasurements on the bone, or angle of the saw blade arepotential sources of deviance.The methods developed and used for limb alignmentplanes and postoperative analysis were novel and com-pleted using 3D planning software. The frontal, sagittal,and axial planes of the proximal limb were based on asubjective visual assessment of the proximal antebra-chium/distal humerus.3,8Target osteotomy planes weremeasured in relation to these neutral planes on both thevirtual and freehand corrections. Postoperative CT scanswere individually shape-matched to the preoperativeproximal limb using an automated iterative global 3Dsurface superimposition tool (global registration,3-Matic). This is an established strategy for overlay ofimages and differential assessment with a precision of<0.5 mm depending on points or surface structure.14Thisapproach allowed for the direct comparison of the loca-tion and angle of the executed osteotomy and wedge tothe intended virtual target. This strategy can be exploredfor use in clinical cases to precisely examine outcomes inthree dimensions.The time required for osteotomy execution after free-hand templating or guide placement was evaluated inthis study although the clinical relevance is limited with240 TOWNSEND ET AL . 1532950x, 2024, 2, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.13968 by Cochrane France, Wiley Online Library on [14/02/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensenormal dog cadaver limbs. Times were typicallyb e t w e e n4a n d5 m i nf o rw e d g e sa n d1 –2m i n u t e s f o rthe single oblique plane osteotomy. Freehand singleoblique plane osteotomies took twice as long as 3Dguided but a difference of 1 minute in the overall dura-tion of a deformity correction is negligible. The time forosteotomy execution and co rrected alignment in limbswith deformity may provide more clinically relevantcomparisons. Subjectively, the guides were easy to applyt ot h ed i s t a lr a d i u s .T h eu s eo ft h ee x t e n s o rg r o o v ea saunique anatomic landmark for guide contouring andplacement instilled confidence in the novice residentsurgeon. Execution of the FH osteotomies was morechallenging in group 1, but confidence and efficiencyincreased as would be expected with repeated osteotomyperformance.Computed tomography-b ased 3D planning andadditive manufacturing of 3D PSGs is now feasible,efficient, and cost effective.11,15,16Orthopedics andbone deformities are a nat ural target due to ease ofautomated threshold-based segmentation of bone andthe technical challenge of a ssessment and successfulcorrection of complex cases. The 3D-PSGs offer anoperative tool to take a complex alignment assessment(degrees of difference in three planes) and ensure accu-racy in intraoperative execution. Guides provide bothnovice and experienced surgeons added comfort in theexecution of a technique but does not replace good sur-gical acumen. Guides are typically built with a base con-toured to the normal anatomy that creates a key-in-lock fitof the guide onto the bone, which is essential to achievethe intended target. Outcomes and operative time savedmay outweigh time and resources required for 3D planningand manufacturing of guides, although this analysis hasnot been explored.The authors have experienced a paradigm shift intheir practices having collectively performed hundreds ofdeformity corrections FH, prior to a change in the past 5 –10 years performing nearly all clinical cases using 3DPSG osteotomy and alignment guides. Anecdotally, theease of guide application, lack of intraoperative subjectiv-ity, and reduction of surgical time are dramatic improve-ments with current 3D PSG. More objective data tosupport these observations and comparisons in affecteddeformity cases are targets of future work.Limitations of this study include use of normal exvivo dog limbs. Subjective freehand alignment assess-ment in limbs with bone deformity is more challenging,which may have led to greater differences in comparisonwith guide use. We only evaluated osteotomy executionas we did not feel reduction of bone ends into a mala-ligned orientation would be clinically relevant. In theauthors ’experience, 3DP alignment guides provided aneven greater benefit than osteotomy guides in achievingoptimal clinical outcomes.Our data would suggest that as the complexity of thedesired osteotomy increases, the guides become morecritical. The use of guides resulted in more consistentacceptable outcomes across all osteotomy types. Theadvanced 3D methods used for limb alignment and 3Doutcome assessment may be useful and improve clinicalassessments. Future work evaluating 3D PSG in limbswith deformities may provide additional guidance torefine clinical case selection more effectively.ACKNOWLEDGMENTSAuthor Contributions: Townsend A, DVM: Studydesign, data acquisition, manuscript preparation.Guevar J, DVM, MVM, DECVN, MRCVS: Studydesign, manuscript preparation. Oxley B, MA, VetMB,DSAS(Orth): Study design, manuscript preparation.Hetzel S, MS: Statistical analysis, manuscript preparation.Bleedorn J, DVM, MS, DACVS-SA: Study conception,data acquisition, manuscript preparation.The authors would like to thank Dr Sun Young Kimof Purdue University for his assistance and expertise inthe single oblique osteotomy.CONFLICT OF INTEREST STATEMENTBill Oxley is the founder and owner of Vet3D. Theauthors declare no other conflicts of interest or financialinterests related to this report.ORCIDJason Bleedornhttps://orcid.org/0000-0003-2987-7722

Answer 17

Results of this retrospective study revealed that on CT and MRI, CC can be identified in most cats. Having a deep knowledge of the normal anatomy of the ab -dominal lymphatic vessels is important to avoid confu -sion with pathologic conditions, such as retroperitoneal lymphadenopathy (aortic or renal lymph nodes altera -tions), neurogenic tumors, abscess, or hematomas, even fluid collections due to discospondylitis.2,3The CC was consistently visualized in 100% of the post–IV contrast CT studies and 95% of the MRI stud -ies. This percentage is like that reported using the same techniques in dogs.7,8 A recent study9 evaluating the vi -sualization of the lymphatic system in delayed nonselec -tive contrast-enhanced CT in cats revealed spontaneous contrast enhancement of the CC in 80% to 91% of pa -tients, which is similar to the results of the present study.The 3 MRI studies where the CC was not visual -ized did not have transverse sequences, which might be a limitation in the detection of the CC. In a human MRI study,2 the CC was reported as visible in only 15% Figure 5 —Transverse CT images of the CC of a cat at the level of L2. The pre- (A) and postcontrast (B) images us -ing a soft tissue algorithm (window width, 300 HU; win -dow level, 40 HU) with a 1.5-mm slice thickness. In panel A the mean CT attenuation of the CC was 7 HU, and in panel B the mean CT attenuation of the CC was 22 HU.In all MRI cases where it was visible, the CC was isointense to CSF, hyperintense to muscles on T2w, and isointense to the muscles on T1w. The T2w signal intensity was classified as homoge -neous in 44 of 60 (73%) and heterogeneous in 16 of 60 (26%) cases. Intravenous contrast was adminis -tered in 28 cats. In 5 of 28 patients, the CC showed homogeneous contrast enhancement being clas -sified as mild (2/5 cases) or marked (3/5 cases; Figure 6 ). In 23 of 28 cats (82%), no postcontrast enhancement was detected.Figure 6 —Transverse MRI images of the CC in a cat (blue arrows) in T1-weighted (A) and T1-weighted postcon -trast (B) sequences (1.8-mm slice thickness) in relation to the AO (black arrows). The CC was at the level of L3.Unauthenticated | Downloaded 12/24/23 09:29 AM UTC6 of 200 patients. A possible explanation for the low detection rate in this study could be the inclusion cri -teria, as only HASTE (half-Fourier single-shot turbo spin-echo) sequences in the dorsal-coronal plane were included, without transverse planes available for revision, like the 3 cats without transverse planes in our study. Previous MRI and CT studies7,8 in dogs have also shown that the CC might be not visible in some cases. Possible explanations are a variation in morphology from the classic appearance and the small size of the CC impairing the identification, but also the possibility of an absent CC in some patients.The shape, location, and width of the CC were also like those reported in cats with idiopathic chylo -thorax by means of lymphangiography.4,10In the present study, the CC was found at the level of (62%) or slightly caudal to (36%) the origin of the cra -nial mesenteric artery. In more than two-thirds of cases (67%), it was ventral to L2. This is like that reported in cats during postmortem studies1 and in lymphangiog -raphy.4,10 This differs from that described in dogs, where it is mainly located ventral to the L4 vertebra.7,8 In other domestic mammals11 (pigs, ruminants, rabbits, horses) the location of CC ranges between T12 and L2 vertebrae.In more than two-thirds of the cases, the CC was dor -sal to the abdominal aorta. In the remaining cases, it was dorsolateral to the aorta, being more frequently located to the right (20 cases) than to the left (9 cases). These anatomical variations have been previously reported in cats using other diagnostic imaging techniques and di -rectly during surgery.4,10 In dogs, the CC was identified in contact with the aorta most commonly on the right side, followed by a dorsal or right dorsolateral location and, in a few cases, dorsolateral to the aorta on the left side.7,8The shape of the CC in cats was described as crescentic in most cases (62%), followed by oval (33%) and triangular (3%). These variations are like those described in dogs by CT7 and MRI.8 In other domes -tic mammals,11 the anatomic appearance of the CC is variable: in the pig and horse, it is elongated oval or spindle-shaped. It is very pleiomorphic in ruminants; in some cases it is present in the form of elongated loops arising from the lumbar trunks and collecting into the thoracic duct, whereas in others, 1 or 2 barely thick -ened elongated lymph trunks correspond to the CC.11The size of the CC was, as expected, different from that reported in dogs7,8 using similar techniques. In dogs,7 the CC has been measured in relation to the body weight and to the aortic diameter (Ao:CC ratio). In cats, the association between the CC size and body weight has not been performed, as there is not as much varia -tion in body weight between cats as in dogs. The mean diameter of the CC in our study is similar to the mean diameter for dogs < 20 kg reported in a previous report.7The variable size and shape of the CC between pa -tients can be a normal individual variation or due to dy -namic/temporal variations as described in dogs.7 Factors such as recent ingestion of fatty foods, use of certain anesthetic agents, and systemic blood pressure may af -fect the imaging characteristics of the CC. Unfortunately, due to the retrospective nature of the present study, this information was not available for all the patients, and correlation with these factors was not possible. Another factor that might influence the size and shape of the CC is the position of the patient during the scan. It is logical to think that the dorsal position might be associated with compression of the CC by the abdominal viscera, chang -ing the size and shape of the CC. Due to the retrospective nature of the study, patients in both dorsal and sternal positions were included. All the MRIs were performed in dorsal decubitus, limiting a possible comparison with data obtained in the sternal position. Nearly half of the CTs were obtained in each position, but as the number of cases is low, the same patient was not scanned twice in sternal and dorsal position, and other potential factors of variability were not controlled, interpreting possible variations is controversial. Prospective studies are needed to further evaluate the influence of these factors on the size and shape of the CC in cats. During fluoroscopic stud -ies in people, it has been observed that the caliber of the normal CC can be altered by contraction waves caused by the alternation of constriction and dilatation of the smooth muscle of the lymphatic wall.2,12 No such varia -tions have been observed in CT or MRI.12,13 Further inves -tigation is needed to assess how physiological factors can influence the shape and width of the CC in cats and to assess whether there are any variations in size in patients suffering from different diseases.The mean CT attenuation of the CC in cats (17.35 ± 4.82 HU) is subjectively considered similar to that reported in dogs.7,14 A wide range of CT attenuation values have been described for the CC in dogs14 and people.13,15 Negative values of chyle, due to the pres -ence of micellar fat, have been described in dogs7 and in people.13,15 Slight differences in attenuation values could be related to different dietary fat and protein in -take. In addition to fat associated with chylomicrons, protein, a small amount of iron, or even protein-bound iodine is transported through the intestinal lymphatic flow to the CC.15 This could potentially explain the wide range of HU encountered. In this study, no negative HU values were observed in the CC of cats, similar to the results by Carvajal et al14 in dogs. The cause for the higher values (30 HU) in cats is unknown, but the inclu -sion of the adjacent soft tissue in the region of interest and partial volume artifact cannot be totally excluded.7On MRI, the CC was isointense to the CSF on T2w images and isointense to muscle on T1w images, as it occurs in dogs8 and humans.2 When available (15/19 cases) in this study, postcontrast enhancement was classified as mild on CT. Previous human studies16 have suggested that the lack of contrast enhance -ment could be used to distinguish CC from lymphade -nopathy. However, this suggestion is not supported by our study or by the studies made on dogs.7 It is unclear why the CC shows contrast enhancement on postcontrast CT. Previous studies have considered the possibility of artifactual enhancement due to partial volume with adjacent structures or due to normal drainage of contrast.17 A recent study9 hypothesized that major lymphatic structures, such as the CC, are well visualized in postcontrast CT studies due to the high contribution of the liver to the total lymph flow and to the direction of the abdominal lymphatic flow.The mean precontrast attenuation of the CC was 17.35 HU ± 4.82 (reference range, 10 to 30 HU) , and Unauthenticated | Downloaded 12/24/23 09:29 AM UTC 7the mean postcontrast attenuation was 27.95 ± 11.01 HU (reference range, 12 to 44). Postcontrast CT se -ries were obtained in 19 cases. In 4 of 19 (21%) cases, no contrast enhancement was detected. Postcontrast enhancement was observed in 15 of 19 (78%) cases and was classified as mild in all of them. No postcon -trast CC enhancement was detected in 83% of the MRI cases, similar to the values for dogs.8 In people, post -contrast enhancement is uncommon on MRI; however, there are descriptions of contrast enhancement in de -layed sequences obtained more than 10 minutes after contrast administration.2,16 A limitation of the present study is that enhancement in MRI postcontrast images was assessed subjectively, and subtle degrees of con -trast enhancement might have been misclassified.Although the differences in the ability to identify the CC in postcontrast CT and MRI are minimal (100% vs 95% respectively), we can theorize that the visualiza -tion of the abdominal lymphatic pathways in cats can be better on CT than on MRI, as it was visible in all the CT cases but not in all the MRI cases. However, the ret -rospective nature of the study, the lack of transverse MRI images in 41% of cases, and the lack of an opti -mized protocol for the CC might have influenced these results. Further prospective MRI studies focused on the lymphatic vessels are necessary to confirm this theory.The main limitation of the present study is its ret -rospective nature, which results in the lack of imaging optimization for the lymphatic system and a lack of con -trol of factors that might influence the size and shape of the CC. Another limitation is the smaller number of CT cases compared to MRI cases. This is explained by the inclusion criteria, as several animals that underwent CT examination had diseases that might have been as -sociated with lymphatic pathology and therefore were excluded from the study. Other limitations were mea -surements obtained by a single observer and the lack of gross anatomy or histopathologic evaluation of the CC.Visualization of the CC using postcontrast MRI and CT7–9 is a less invasive method than CT- lymphangiogra -phy.4 Although lymphangiography remains the gold stan -dard for the evaluation of the lymphatic vessels,4,14 pro-spective studies are needed to optimize the CT and MRI protocols for the lymphatic system in cats, particularly of the thoracic duct, as it might be helpful as a noninvasive alternative for surgical planning in cases of chylothorax.In conclusion, MRI and CT are potential noninva -sive methods for evaluating the CC in cats.AcknowledgmentsProject planning, project implementation, data analysis and interpretation, manuscript writing, and editing and manu -script submission were performed by Dr. Gómez Martín. Proj -ect planning, project implementation, data interpretation, and manuscript editing were performed by Dr. Domínguez Miño.The authors would like to thank the dedicated veterinary technicians (EM and SF) at Anicura Ars Veterinaria for their important role in completing this study. Special thanks to all participating cats and their owners.DisclosuresThe authors have nothing to disclose. No AI-assisted technologies were used in the generation of this manuscript.FundingThe authors have nothing to disclose.

Answer 18

This study demonstrated an increased incidence of gunshot wound injuries in companion animals presenting to an urban level 1 veterinary trauma center during the COVID-19 pandemic. A shift in the predominant location of injury was also identi -fied. Injuries to the extremities and thorax were more common prior to the pandemic, compared to a pre -dominance of maxillofacial and cervical injuries after the start of the pandemic. In particular, there was a statistically significant increase in the number of maxillofacial injuries during the pandemic period ( P = .04). This finding may reflect more targeted acts of violence during the pandemic, as maxillofacial and cervical wounds typically result from point-blank or close-range aggression with the animal facing the firearm.14 There is a possibility that this injury dis -tribution may be related to increased reports of do -mestic violence and assaults during stay-at-home orders, as animals may come to the defense of own -ers during altercations and suffer resultant injuries. Alternatively, animals may simply be inadvertent bystanders caught in the crossfires of violent acts centered around households where individuals spent more time during stay-at-home directives and the subsequent era of social distancing guidelines.15 Ul-timately, in most cases, the specific details regard -ing how the gunshot injuries occurred could not be determined due to the retrospective nature of this study and because most injuries (80%) were either unwitnessed or had an unspecified history in the medical record. In the author’s experience, it is com -mon for limited information to be given to the veteri -narian regarding the circumstances surrounding the gunshot injury. This is often due to individuals such as police, family members, or rescue organizations seeking care for the animal initially or, in other cases, could be due to concern on the part of the pet owner for potential legal implications.Similar to our prepandemic findings, 2 of the most recent studies12,14 investigating gunshot inju -ries in dogs and cats reported the extremities and thorax as the most common locations affected. In a 1997 paper14 evaluating 84 cases of gunshot wounds in dogs and cats, approximately 43% of injuries were sustained on the limbs and 26% involved the thorax. Head and neck injuries were the next most com -mon, representing 16% of all injuries, with the ab -domen and vertebral column least affected at 11% and 3%, respectively. A 2014 study12 consisting of 37 cases of gunshot wounds in dogs and cats found that injuries to the forelimbs and hind limbs com -prised approximately 32% of cases, while thoracic Gunshot wound location Prepandemic Pandemic P valueMaxillofaciala 1/9 (11%) 9/16 (56%) .04Cervical 1/9 (11%) 7/16 (43%) .182Thoracic 3/9 (33%) 2/16 (12.5%) .312Extremities 5/9 (55%) 4/16 (25%) .200Vertebral/spinal 2/9 (22%) 1/16 (6%) .530Abdominal 2/9 (22%) 0/16 (0%) .120Percentages represent the proportion of total gunshot wound patients per admission time period with injuries to each specified location. Categories are not mutually exclusive, as patients could have had injuries to multiple locations.aThe proportion of injuries within a location category is sig -nificantly ( P < .05) different between the admission time periods.Table 1 —Distribution of gunshot wound injuries in dogs and cats in the prepandemic (March 2018 to February 2020) and pandemic (March 2020 to February 2022) admission time periods.One dog was injured due to the accidental discharge of a firearm within the household, 2 patients were inadver -tently wounded during altercations between their owners and other individuals, and the remainder of injuries were either unwitnessed or unspecified in the medical record. Among the patients with recorded trauma scores, the median ATT score was 8.5 (range, 3 to 10) and the me -dian MGCS score was 17.5 (range, 14 to 18). Three pa -tients were humanely euthanized, and 6 patients survived to discharge after receiving additional care. Among the survivors, 5 patients were admitted for hospitalization with a mean length of stay of 5.6 ± 5.2 days and 1 patient was treated on an outpatient basis. Three patients under -went surgery, with the following procedures performed: 2 patients required wound exploration and debridement, 2 patients required amputation (1 digit amputation and 1 left forelimb amputation, both due to comminuted frac -tures), and 1 patient required both a median sternotomy and exploratory laparotomy for bicavitary hemorrhage.Pandemic: March 2020 to February 2022The distribution of injuries was as follows: maxillo -facial (56%), cervical (43%), extremities (25%), thoracic (12.5%), vertebral/spinal (6%), and abdominal (0%; Table 1). One dog was inadvertently injured during an alterca -tion between its owner and other individuals, 1 dog was wounded while attacking another dog, and the remain -der of injuries were either unwitnessed or unspecified in the medical record. Among the patients with recorded trauma scores, the median ATT score was 4 (range, 2 to 7) and the median MGCS score was 16.5 (range, 15 to 18). Three patients were humanely euthanized, and 13 patients survived to discharge after receiving additional care. Among the survivors, 6 patients were admitted for hospitalization with a mean length of stay of 2.2 ± 1.2 days and 7 patients were treated on an outpatient ba -sis. The single cat included in the study sustained inju -ries to the cervical and vertebral/spinal regions and was Unauthenticated | Downloaded 12/04/23 07:12 AM UTC JAVMA | DECEMBER 2023 | VOL 261 | NO. 12 1865injuries comprised 22% of the cases. Injuries to the head and neck each comprised roughly 16% of the included cases, and abdominal injuries occurred in 14% of cases. Young male dogs were overrepre -sented in both studies,12,14 as was also true in our study. The overall survival rate in our study was 76%, which is also comparable to that reported in other studies,12,14 suggesting that animals with gunshot injuries can achieve good outcomes. Whereas dog breeds traditionally considered working breeds were overrepresented in one of these previous studies,12 pit bull-type dogs and mixed-breed dogs comprised the majority of patients in the present study. This was likely attributed to regional differences in breed popularity and preference, as well as the fact that hunting, which accounted for numerous injuries in the aforementioned study,12 is less common in the urban environment where our institution is located.Although other studies have described charac -teristics and treatment of gunshot wounds in dogs and cats, this was the first study to analyze the patterns of such injuries within the context of CO -VID-19 pandemic–related violence. This is particu -larly important because the correlation between the pandemic and increased violence has been well-documented in people.1 A dramatic increase in the number of firearm background checks was reported by the Federal Bureau of Investigation during the ini -tial stages of the pandemic,2 and the Brookings In -stitute estimates that nearly 3 million more firearms were purchased during the pandemic compared to the same period in 2019.7 The Pennsylvania Instant Check System processed 1,445,910 background check requests in 2020, making it the highest-vol -ume year since its inception in 1998. In 2020, a total of 1,141,413 firearms were reported in Pennsylvania as purchased or transferred, compared to 766,204 firearms in 2019.16 Increases in crime were report -ed nationwide concurrently with this rise in firearm sales, and gun violence reached new heights in Phila -delphia following implementation of pandemic ordi -nances. One study10 documented a 62.4% increase in gunshot wounds in Philadelphia during the early stages of the pandemic (March 16, 2020, to May 30, 2020) when compared to previous years. Similarly, reports of shootings throughout the city increased during a similar time frame, with data showing an approximately 7% increase in shooting victims during the period of April 1, 2020, to April 15, 2020, com -pared to the same time of the prior year.17 Given that our hospital is located in Philadelphia, a busy urban setting in which changes in patterns of violence as -sociated with the COVID-19 pandemic are particu -larly evident, we believe that the increased number of gunshot wound injuries reported in this study are reflective of the ramifications that such violence can have on companion animals.In conjunction with reports of intensifying violence across the country, numerous human hospitals noted an increase in admissions for gunshot wound injuries. One study8 investigating admissions to all trauma cen -ters in Pennsylvania found an increased incidence of gunshot wound injuries during the pandemic despite a decrease in total trauma admissions, with a > 4-fold increase in penetrating injuries in the city of Phila -delphia. A review of patients presenting to a level 1 trauma center in Philadelphia demonstrated a great -er proportion of intentional violent injury, especially from firearms, following enactment of stay-at-home orders.10 Similarly, trauma centers across numerous other states documented a significant rise in gunshot wound victims following the onset of the COVID-19 pandemic.4,6,7 Interestingly, while most studies in the human literature do not compare localization of gun -shot injuries before and after the pandemic, 1 study5 reviewing patients in the trauma registry at an Atlanta hospital found an increased incidence of patients sus -taining gunshot wounds to the head and neck during the COVID-19 pandemic, although no explanation was proposed to account for this phenomenon. This sug -gests that our findings of both an increased incidence of gunshot wounds and a shift in the predominant lo -cation of gunshot injuries sustained in companion ani -mals during the COVID-19 pandemic parallel patterns observed in some human healthcare settings. Accord -ingly, by monitoring trends reported in human medi -cine, particularly during unprecedented circumstances such as the COVID-19 pandemic, veterinarians may better predict and thus prepare for similar problems af -fecting their patient population.There were several limitations of this study. This was a retrospective review and thus was subjected to bias, confounding variables, missing data, and other weaknesses common to this study design. For example, trauma scoring (ATT and MGCS) was not available for most animals included in the study, pre -cluding an evaluation of injury severity between pa -tients in the 2 admission time periods. Trauma scores may not have been recorded for a variety of reasons, including an unprecedented increase in emergency caseload at the start of the pandemic, shortage of personnel for trauma registry data entry due to changes in hospital staffing and responsibilities, or lack of house officer knowledge of the requirement to document trauma scores.Additionally, the results published in this study were collected from a single veterinary trauma center in Philadelphia and therefore may not be applicable to the entire veterinary community. It is also possible that there is a cohort of gunshot injury patients that were treated by other area hospitals without subse -quent referral or that were not presented for care if the animal died at home or the injury was perceived to be minor. Therefore, the true incidence of gunshot injuries may be greater than what is reported in this study. Although the increased incidence of compan -ion animal gunshot injuries in this study were attrib -uted to changes in violence linked to the COVID-19 pandemic, the higher number of cases may have been driven by unrelated factors. Lastly, and perhaps most importantly, our study featured a small sample size and accordingly lacked sufficient power to dem -onstrate a statistically significant difference between prepandemic and pandemic gunshot wound injuries. A follow-up study evaluating cases from multiple in -stitutions could be considered to better characterize Unauthenticated | Downloaded 12/04/23 07:12 AM UTC1866 JAVMA | DECEMBER 2023 | VOL 261 | NO. 12such patterns in gunshot-related injuries. Neverthe -less, we believe that the current study identifies find -ings relevant to our patient population and sheds light on how societal dynamics can affect animal health and welfare.AcknowledgmentsNone reported.DisclosuresThe authors have nothing to disclose. No AI-assisted technologies were used in the generation of this manuscript.FundingThe authors have nothing to disclose.

Answer 19

Our study compared pin placement tracts using FHP and3DPG techniques in a canine cadaveric model. Ourhypotheses were partially supported in that we found agreater rate of intraoperative technique deviations in pinplacement and longer duration of pin placement for theFHP technique but a difference in the distribution ofgrades between the two techniques was not identified.Our results related to the FHP technique are difficultto compare with others due to paucity of similar studiesin the literature. To our knowledge, a FHP techniquesimilar to that described herein has been described inonly two clinical reports5,12(both involving placement ofscrews/pins at lumbosacral joint) and one surgical text-book.6No evidence of vertebral canal compromise wasidentified on postoperative radiographs in one retrospec-tive case series5involving stabilization of lumbosacralfracture-luxations in five dogs. A limitation of thatreport5is that postoperative CT was not performed,which has been shown to be significantly more accuratein identifying canal violation compared with conven-tional radiography.27In people, the pedicle-probing tech-nique is associated with a high degree of accuracy inFIGURE 8 Transverse plane multiplanar reconstruction (MPR) images of pin tracts (free-hand probing [FHP] images [A –C], 3D-printeddrill guide [3DPG]: images [D, E]) assigned grade IIa modified Zdichavsky. For all images, the dog's left is to the right.FIGURE 9 Transverse plane multiplanar reconstruction (MPR) images of pin tracts (all free-hand probing [FHP]) assigned grade IIIamodified Zdichavsky. For all images, the dog's left is to the right.MULLINS ET AL . 655 1532950x, 2023, 5, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.13958by Vetagro Sup Aef, Wiley Online Library on [22/07/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licenseseveral studies, even in cases of spine deformities.25,28 –31Five studies25,28 –30,32that included a total of almost600 patients undergoing posterior stabilization withtranspedicular screws reported medial pedicle wall viola-tion rates of 0.5% –6.3%, with only one screw requiringrepositioning and none associated with neurological orvisceral complications. The medial cortex of the thoracicpedicle has been shown to be thicker than the lateral cor-tex in humans,33–35a factor that may contribute to adecreased rate of medial cortex breach with the pedicle-probing technique in people.Creation of the cortical defect (decortication) was per-formed with a 2-mm drill bit in our study. A spinal burror awl could also have been used as an alternative, as isdescribed in the veterinary and human literature.12,31Inclinical cases, loss of the cis cortex associated with use ofa spinal burr may not be of structural concern as thepolymethylmethacrylate will support this outer corticaldefect. In our study, a 2-mm drill bit was used instead ofa burr as it avoided this loss of cis cortex. The FHP tech-nique described herein does not negate the need to pre-operatively measure ideal pin insertion angles and tofollow these angles intraoperatively. However, adheringto preoperatively measured angles requires accurate iden-tification of optimal entry points intraoperatively. In aprevious description of the technique,6the authors rec-ommend checking the angle of the probe hole with thedesired pilot hole angle to ensure accurate trajectory. Inour study, following creation of the cortical defect, theprobe was inserted at an angle corresponding to the idealpin trajectory based on preoperative CT. This is particu-larly important in the lumbar spine because the probehas more “freedom ”to travel within the vertebral bodycompared with thoracic spine where the probe is con-tained within the confines of the pedicle. Once the probeestablished the safe trajectory, it is removed and replacedwith a drill bit for the pilot hole of the definitive positiveprofile pin. The probe itself should be placed with a drillor by hand using a Jacob's chuck, making sure to allowas much length of pin exiting the chuck to reduce its stiff-ness and allow it to follow the path of least resistancewithin cancellous bone. A positive profile pin should notbe used as a probe because it is too stiff and will not fol-low the path of least resistance. In our study, we used ablunted 2-mm smooth Steinmann pin as the probe,which corresponded to /C2450% –75% the thoracic pediclewidth. In people, straight and curved pedicle probes/awlsare commercially available but are generally larger thanwould be appropriate for canines because of the relativelylarger size of the pedicle in people.31,36,37In recent years,probes with an electrical impedance conductivity-measuring device have been developed to improve accu-racy of pedicle screw placement in people.37,38Bymonitoring electrical conductivity in surrounding tissues,these probes can alert the surgeon to an impendingbreach.37,38The 3DPG technique was associated with a very highdegree of accuracy in our study, with 54/56 pins assignedgrade I. Importantly, no pin tracts were graded grade IIb(full penetration of medial pedicle wall) with either tech-nique. This corroborates the findings of previous studiesevaluating use of patient-specific 3DPGs in veterinaryspine surgery.7,15 –19Within such studies involving thethoracolumbar spine,7,15,17,18the rate of grade I Zdi-chavsky (or alternate classification equivalent) rangesfrom 79.3% to 100%. A similarly high accuracy rate hasbeen demonstrated with use of 3DPGs in cases with ver-tebral malformations.15In human spine surgery, 3DPGsare associated with improved pedicle screw placementaccuracy, and decreased surgical time and intraoperativeblood loss.39–41Unilateral 3DPGs were used in our studyand have been shown to be highly accurate andFIGURE 10 Transverse plane multiplanar reconstruction (MPR) images of pin tracts (all free-hand probing [FHP]) of vertebrae inwhich an intraoperative complication occurred. For all images, the dog's left is to the right.TABLE 3 Mean (SD) duration ofpin placement for pins inserted by3DPGs and FHP in thoracic spine,lumbar spine, and overall.Thoracic Lumbar Overall3DP Mean (SD) duration of pin placement (min) 2.8 (1.6) 2.3 (0.93) 2.6 (1.3)FHP Mean (SD) duration of pin placement (min) 4.2 (1.9) 4.9 (1.7) 4.5 (1.8)Abbreviations: 3DPG, 3D-printed drill guide; FHP, free-hand probing.656 MULLINS ET AL . 1532950x, 2023, 5, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.13958 by Vetagro Sup Aef, Wiley Online Library on [22/07/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensecomparable to bilateral guides.18In one study,18unilat-eral guides were associated with decreased exit distancedeviation compared with bilateral guides. We did notevaluate or compare planned versus achieved insertionangles or entry/exit point deviations in our study as theFHP technique relies on the probe following the path ofleast resistance and establishing a safe trajectory andwould not be expected to have the same degree of accu-racy as 3DPGs regarding these variables. A modificationof the modified Zdichavsky classification described byElford and colleagues15was created for grading of lumbarpin tracts in our study. The original Zdichavsky classifica-tion is validated for thoracic pedicle screws in humans,and is associated with a high rate of inter- and intraobser-ver reliability.42A higher rate of intraoperative technique deviationsin pin placement was found using the FHP technique.Two of these deviations involved bilateral unintentionalpenetration of the ventral vertebral cortex of T11 with theprobe during instrumentation of the first vertebra oper-ated and did not occur in subsequent vertebrae/cadavers.Although both pin tracts were palpated and completelysurrounded by bone, and subsequently assigned grade Ion postoperative CT, such uncontrolled ventral cortexbreach could be associated with injury to intrathoracicstructures.43,44In people, anterior (ventral) vertebral cor-tex breach is avoided for this reason,45with the medialand lateral cortices of the pedicle contributing a signifi-cant portion of pedicle screw pull-out strength.46In thesame cadaver, the initial cortical defect at L6 was createdtoo dorsal and vertebral canal entry was identified withinitiation of probing. This highlights the importance ofcorrect identification of the optimal pin entry pointintraoperatively. In our study, we used the accessory ormammillary process in the thoracic spine and accessoryprocess in the lumbar spine as intraoperative landmarksfor identification of optimal pin entry points, as previ-ously described.6In clinical situations where pin entrypoint is inadvertently created too dorsal, we suspect thatthe FHP technique as performed in our study may offer agreater ability to detect this complication compared withthe conventional freehand drilling technique, and possi-bly be associated with less injury to vertebral canal con-tents. The remaining three intraoperative deviationsinvolved the probe exiting the dorsolateral cortex of thepedicle (thoracic spine) or the ventrolateral vertebralbody (lumbar spine), and in all three cases, this complica-tion was recognized immediately and the probe redir-ected more medially/horizontally. With the exception ofvarying degrees of canal violation and undesired screwpenetration of the ventral vertebral cortex identified onpostoperative imaging,12no other specific intraoperativecomplications related to the pedicle-probing techniquehave been described in the veterinary literature.5,12Fewstudies report the occurrence of intraoperative complica-tions/deviations associated with use of 3DPG in the veter-inary literature.18In one ex-vivo canine study,18breakageof a 3DPG was reported in two cases. We did not observeguide breakage in our study.Duration of pin placement was longer with the FHPtechnique in the thoracic spine, lumbar spine, and over-all, in our study. Duration of pin placement included allsteps that would be required for pin placement in a clini-cal case once the approach was completed. Duration ofpin placement was defined in this way because of soft tis-sue dissection performed for exposure of one FSUinfluencing dissection time required for an adjacent FSU.Although duration of pin placement was longer for pinsplaced by FHP technique, the clinical significance of amean difference of 1.9 min is negligible in the overalloperating time. Furthermore, the time taken to plan bothtechniques was not recorded. It is likely that the timetaken to design and create 3DPGs would have farexceeded the time for FHP planning.We acknowledge several important limitations. Thiswas an ex-vivo study that included only a single largebreed without spinal fracture/luxation and our resultsmay not be replicated in small/medium breeds or differ-ent breed conformations. In particular, in the lumbarspine, the ability of the drill bit (associated with decorti-cation) to drop into the cancellous bone between theinner and outer cortices, which is central to the principleof the FHP technique, would be more challenging insmaller breeds with narrower pedicles. The fact that asingle breed was used likely advantaged the FHP tech-nique because of uniformity between cadavers and verte-brae. The study also included a small number ofcadavers. 3DPGs are associated with a high degree ofaccuracy in patients with spinal malformation/deformityand whether the FHP technique would perform as wellin such cases is unknown.7,15,17,18The authors refrainedfrom the use of inferential statistics in this study andinstead reported only the raw data. On the basis of thelack of previously published data on the FHP technique,it was not possible to estimate a priori the smallest sam-ple size needed to show a significant difference if it wereto exist. Therefore, it is possible that even if one of thetechniques evaluated in this study was associated withcomplete breach of the vertebral canal on one or twooccasions, this may not have reached statistical signifi-cance but would be of substantial clinical significance.All pins were placed by a single experienced surgeon,and it is likely that this had an effect on the high degreeof accuracy with both techniques in this study. Pins wereremoved following placement to prevent placement ofone pin influencing that of a subsequent pin by the sameMULLINS ET AL . 657 1532950x, 2023, 5, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.13958 by Vetagro Sup Aef, Wiley Online Library on [22/07/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licenseor alternate technique and to eliminate beam hardeningartifact on postoperative CT. A disadvantage is that wecould not evaluate for deviations such as excessively longpins or pins penetrating/abutting pleural, visceral or vas-cular structures. The extensiveness of the surgicalapproach performed in this study would be greater thanthat required in a clinical case, which is likely to haveimproved visibility of relevant anatomical structures andthe surgeon's ability to place the pins. Finally, no postop-erative dissection was performed to evaluate for injury tointrathoracic or abdominal structures.Our study confirmed both FHP and 3DPG techniqueswere accurate for placement of spinal fixation pins incanine cadavers. The 3DPG technique reduced intrao-perative technique deviations in pin placement and dura-tion of pin placement in our study but this techniquerequires greater software expertise and equipment forguide design and manufacturing. The FHP techniqueoffers a very versatile and safe method of insertion of spi-nal fixation pins and can be performed immediately with-out potential delays associated with guide design,printing and delivery. Further studies are required toconfirm our results in clinical cases.AUTHOR CONTRIBUTIONSMullins RA, MVB, DVMS, DECVS, PGDipUTL, MRCVS:Study conception and design; data acquisition, analysisand interpretation; manuscript preparation and review.Espinel Ruperéz J, LV, MS, PhD, DECVS, Ortega C,DVM and Hoey S, MVB, DECVDI, DACVR: Studydesign, data acquisition, analysis and interpretation;manuscript preparation and review. Bleedorn J, DVM,MS, DACVS-SA, Kraus KH, DVM, MS, DACVS andGuevar J, DVM, MVM, DECVN: Study design, data anal-ysis and interpretation, manuscript preparation andreview. Hetzel S, MS: Statistical analysis and manuscriptreview.ACKNOWLEDGMENTOpen access funding provided by IReL.FUNDING INFORMATIONThe study was funded by an Overhead Investment Plan(OIP) grant from University College Dublin Research(Ref.No.: 64725), Innovation and Impact Committee,Dublin, Ireland. The work of Scott Hetzel of the Biostatis-tics and Epidemiology Research Design Core was fundedby Institutional Clinical and Translational Science AwardUL1 TR002373.CONFLICT OF INTEREST STATEMENTThe authors declare no conflicts of interest related to thisreport.ORCIDJorge Espinel Ruperézhttps://orcid.org/0000-0003-3170-9306Jason Bleedorn https://orcid.org/0000-0003-2987-7722Seamus Hoey https://orcid.org/0000-0003-1049-7658

Answer 20

This study investigated a unique population of dogs and cats presenting with acute spontaneous adrenal hemorrhage and demonstrated that, in this cohort, a delayed surgical treatment was superior to emergent surgical treatment. Additionally, local recurrence and metastasis appeared to occur rarely.The results confirmed our clinical impression that medical management may allow for acute he -mostatic control, potentially because of the enclosed nature of the retroperitoneal space. Interestingly, some dogs and cats presenting with peritoneal effu -sion also responded favorably to initial conservative treatment despite the larger spaced cavity. There -fore, if cardiovascular stabilization can be achieved, results of the study suggested the procedure should be delayed, which might allow for improved surgi -cal visibility and hemodynamic control. Most previ -ous case reports6,17,18,20–22 include dogs receiving emergent surgical stabilization due to cardiovascu -lar decline despite medical management. A guarded outcome with a 50% perioperative mortality rate was also reported for 8 dogs receiving emergent adre -nalectomy.6 Overall, limitations in anesthesia, critical care, and surgical support on emergency may play a role in the poorer outcome. It is also possible that cases selected for emergent surgery were more un -stable on presentation in our cohort. However, the absence of association between surgery timing and preoperative peripheral PCV, lactate, platelet count, coagulation parameters, BP, or imaging evidence of rupture seems to indicate that the decision to per -form the procedure on an emergent basis would rather have been related to institution and/or sur -geon preferences. The retrospective nature of the study precludes further conclusion regarding the clinical reasoning behind this surgical decision. The ideal timeline at which surgery should occur remains unclear, and the present study along with our clini -cal impression seems to suggest that a few days to a week would suffice. Finally, the study reinforces the importance of preoperative diagnostic imaging in identifying the source of hemorrhage in cases of hemoperitoneum, and adapting surgical timing and preparation accordingly.Spontaneous adrenal tumor rupture is also a rare condition in human medicine, and reported mortality rates of 45% for emergent adrenalectomy have led to delayed surgical treatment when hemodynamic stabil -ity can be achieved.23 Marti et al23 established a treat -ment algorithm based on a patient’s hemodynamic stability and endocrine testing and recommended in -terval imaging at 3 and 6 months to monitor hematoma resolution and allow time for inflammation to subside. Emphasis on patient stabilization and pretreatment appears critical in cases of functional tumors . In se -lected cases of nonfunctional tumor, adrenalectomy might ultimately not be elected.23 Additionally, arte -rial embolization is frequently implemented preoper -atively to help control hemostasis, with success rates of up to 82% reported in the acute settings.24 It has also shown satisfactory efficacy as the sole treatment for inoperable tumors or to obtain tumor size reduc -tion, functional resolution, and alleviate pain with no serious adverse reactions.25 Case reports26,27 of arte -rial embolization demonstrate effective hemodynam -ic stabilization of veterinary patients presented with continuous epistaxis or hemoperitoneum secondary to ruptured liver mass. However, its use remains an -ecdotal in veterinary medicine and has not been in -vestigated to our knowledge in cases of spontaneous adrenal hemorrhage.Adrenal tumor types represented in the current study were similar to those previously reported for nonruptured cases in dogs and cats, excluding a rare case of primary adrenal hemangiosarcoma. Pri -mary adrenal hemangiosarcoma or angiosarcoma has rarely been reported in human medicine and displays an aggressive behavior and overall poor prognosis28,29 characterized by a high propensity for local recurrence and metastasis. Intraoperative de -tection of abdominal metastases in this particular case aligns with the general rapid progression of the cancer. Overall, there was a preponderance of adre -nocortical (60%) over medullary tumors (36%); this fact corroborates the findings of Lang et al,6 who de -tail 8 cases of spontaneous adrenal hemorrhage, 7 of which had a tumor of adrenocortical origin. Interest -ingly, pheochromocytoma has been most commonly associated with adrenal rupture in people23,30; other etiologies include carcinoma, adenoma, and myeloli -poma.31 Previous veterinary studies have speculated that tumor size > 2 cm,6,8,24,32 vascular invasion,8 and high percentage necrosis32 could represent underly -ing predisposing factors of rupture. Mean tumor size on CT was 5.8 cm in the current study, which appears subjectively larger than commonly reported.2,4,8,10 Vascular invasion was documented in 37% of his -topathology reports, and percentage necrosis was Figure 1 —Kaplan-Meier survival analysis by tumor type of dogs and cats treated by adrenalectomy for spon -taneous adrenal rupture. The survival analysis includes the entire population of dogs and cats diagnosed with either a pheochromocytoma or an adrenocortical tumor (all types confounded) without censoring short-term mortality or cases lost to follow-up. A numerical but statistically nonsignificant difference in median survival time was noted between pheochromocytoma and adre -nocortical tumors ( P = .583).Unauthenticated | Downloaded 12/04/23 07:18 AM UTC8 inconsistently evaluated to support further conclu -sions. Comparison with a nonruptured adrenal tumor population would be required to investigate predis -posing factors of spontaneous adrenal rupture.Overall, short- and long-term outcomes appeared similar to those previously reported for nonruptured primary adrenal tumors, with a relatively high short-term mortality rate (21%) but low recurrence and metastasis rates leading to prolonged survival with adrenalectomy alone.2,7,9,10,33,34 Few cases under -went adjuvant chemotherapy, considering it is not the standard of care for primary adrenal tumors, and for most cases, treatment was targeted to other tumor sites, which did not allow us to draw clear conclusions regarding its benefit in rare cases of metastasis. Ad -ditionally, only 1 case of local recurrence of adreno -cortical carcinoma was confirmed histologically and may have been related to diffuse metastatic disease. Although nonsignificant statistically, some distinc -tions in outcomes were observed between etiologies. An overall higher postoperative complication rate was noted with pheochromocytoma, which has pre -viously been described as a risk factor for short-term mortality.10 Perioperative mortality, however, was not impacted by the tumor type in the present study. Long-term prognosis appeared overall less favorable for ad -renocortical tumors, with a higher metastatic rate and shorter MST than pheochromocytoma. This survival trend was shared between malignant, benign, and undetermined adrenocortical tumors, which could challenge the reliability of histopathology to rule out a malignant process. In fact, 1 case of adrenocortical adenoma was later diagnosed with metastatic neuro -endocrine carcinoma to the liver based on necropsy and histopathology findings without evidence of an -other primary neuroendocrine tumor. Overall, the low number of cases and the absence of comprehensive long-term follow-up and necropsy related to the ret -rospective nature of the study preclude further con -clusions in that regard. An association between carci -noma and development of metastasis has previously been reported, with compared MSTs of 360 days ver -sus 953 days for the entire study population.8 Other specific retrospective studies13,35 have documented metastatic rates of up to 36% for dogs that presented with adrenocortical tumors. Similar observations have been made in human medicine, with up to 22% meta -static rate on presentation and an increased risk of lo -cal recurrence leading to an overall guarded long-term prognosis with adrenocortical carcinoma.36 Altogeth -er, metastatic rates in the present study remained low compared with those of previous studies,2,7,9,10,33,34 but may have been underestimated owing to the lack of routine necropsy. Size of the tumor, presence of a tumor thrombus, or microscopic metastasis was not associated with survival, in contrast to other stud -ies.3,8,9,33 Finally, although this study includes a mixed population of dogs and cats, the low number of feline cases does not support separate conclusions regard -ing their outcome.A significantly lower short-term survival rate (75%) was found in dogs and cats that received additional sur -gical procedures, compared with those cases strictly limited to adrenalectomy (100%). Other studies9,10 have found concurrent nephrectomy to be a negative prog -nostic factor with an increased risk of acute renal injury postoperatively. This association was confirmed in this study without impacting the short-term survival. Cer -tain procedures appear inevitable, such as performing a ureteronephrectomy in cases of adhesions to the ipsi -lateral kidney or addressing a gastrointestinal obstruc -tion via gastrotomy/enterotomy. However, these re -sults along with those reported previously suggest that any additional procedure that could be avoided should be postponed. Additionally, intraoperative hypotension was significantly associated with increased short-term mortality, particularly within the group that received an emergent procedure. Interestingly, no association was found between hypotension and AKI, although this could reflect a type II error. Finally, preoperative phenoxybenzamine administration was not associ -ated with a more favorable immediate outcome, com -pared with findings in a previously published study.32 This finding of the present study was validated in the entire study population and when cases confirmed as pheochromocytoma on histopathology were selected. The absence of pretreatment in the group that received emergent surgery and had an overall poorer outcome could have induced a bias in the analysis; however, no protective effect was observed in the group that had a delayed procedure and received pretreatment. These findings reinforce ongoing debates regarding the valid -ity of such treatment.9,34Limitations inherent to this study are related to its retrospective multi-institutional nature, including absence of standardization and incomplete medi -cal records, lack of histopathology and necropsy to confirm metastasis, local recurrence, and cause of death. The role of adjuvant therapy for ruptured ad -renal tumors cannot be fully established due to the small number of patients involved, and concurrent neoplasia could have affected survival times.In conclusion, the findings of the present study did not support the need for emergency adrenalec -tomy in cases of spontaneous adrenal rupture, and delayed adrenalectomy can be attempted while maximizing patient hemodynamic stability, as pre -emptive hemostasis might reduce the short-term complication rate. Low reported recurrence and metastatic rates do not provide clear evidence of the need for adjuvant therapy.AcknowledgmentsThe authors thank James B. Robertson, biostatistician at the North Carolina State University College of Veterinary Medicine, for his assistance with the statistical analysis.DisclosuresThe authors have nothing to disclose. No AI-assisted technologies were used in the generation of this manuscript.FundingThe authors have nothing to disclose.Unauthenticated | Downloaded 12/04/23 07:18 AM UTC 9

Answer 21

yCase 1A 10-year-old female intact mixed-breed dog weighing 12.3 kg was presented to The Ohio State University (OSU) Veterinary Medical Center Integrat -ed Oncology Service for evaluation for recurrence of hepatocellular carcinoma (HCC). Sixteen months before presentation, the dog underwent a left lateral liver lobectomy for HCC with incomplete surgical mar -gins, at a different tertiary facility. Following surgical resection, the dog was presented to the same ter -tiary facility for staging with abdominal CT scanning every 6 months. One month before presentation, CT was used to identify a large, mixed attenuating mass arising from the left medial liver lobe. A fine-needle aspiration of the mass was performed under sedation, and cytology was consistent with recurrence of HCC. There was no evidence of pulmonary metastatic dis -ease on 3-view thoracic radiographs.Case 2An 11-year-old male castrated mixed-breed dog weighing 34.5 kg was presented to OSU Vet -a.23.03.0147erinary Medical Center Integrated Oncology Ser -vice for a newly diagnosed hepatic mass. One month prior to presentation, increases in ALT, ALP, and AST were found during routine preanesthetic blood work for a prophylactic dental procedure. An abdominal ultrasound was recommended at that time, and a left-sided hepatic mass measur -ing approximately 8 to 12 cm was identified. There was no evidence of pulmonary metastatic disease on 3-view thoracic radiographs.Diagnostic Findings and InterpretationCase 1At OSU presentation, physical examination results and CBC values were within normal limits. Serum chemistry abnormalities included increased concentrations of ALT (987 IU/L; reference range, 18 to 108 IU/L) and AST (333 IU/L; reference range, 16 to 51 IU/L) as well as hypoglycemia (31 mg/dL; reference range, 67 to 127 mg/dL). Tho -OMEIn case 1, surgery consisted of the removal of the remaining left medial lobe, as well as the central division. Case 2 received a complete left and central division hepatectomy. Histopathology confirmed a diagnosis of hepatocellular carcinoma in both dogs. Liver enzyme resolution and lack of tumor recurrence were confirmed with chemistry panel and abdominal ultrasonography in both dogs.CLINICAL RELEVANCEThis case report describes, for the first time, the clinical management and outcome of extensive hepatectomy in 2 dogs. We propose that extensive hepatectomy, staged or synchronous, is possible in a clinical setting.Unauthenticated | Downloaded 10/08/23 06:32 AM UTC2 racic and abdominal CT were performed for pre -surgical planning and staging. The previous liver lobectomy site was identified with multiple me -tallic staples. Ventral to the staples, a lobular, hy -poattenuating soft tissue mass (5.5 X 5.5 cm) with heterogeneous contrast enhancement was identi -fied involving the left medial liver lobe (Figure 1) . Two ill-defined nodules, measuring 1.3 and 1.4 cm, were identified in the right liver. Based on these imaging findings, tumor recurrence was suspect -ed. No evidence of metastasis or structural abnor -malities were identified within the thoracic cavity.Case 2At OSU presentation, the dog was noted to have bilateral lenticular sclerosis and exhibited moderate stridor during physical examination. An abdominal CT was performed for presurgical plan -ning. A lobular, heterogeneous, hypoattenuat -ing soft tissue mass with contrast enhancement, measuring 12 X 15 X 14 cm, was identified. The mass was highly vascular, compressing and caus -ing dorsal displacement of the intrahepatic caudal vena cava and the portal vein at the porta hepatis within the liver (Figure 1). The mass was identi -fied as being centered in the region of the right medial lobe and expanding centrally. Addition -ally, a hypoattenuating, rim-enhancing soft tissue nodule, measuring 1.5 cm, was in the left liver. The thoracic cavity was not evaluated with CT. Based on these imaging findings, primary hepatic tumor occurrence was suspected. Ultrasound-guided fine-needle aspiration of the larger mass was per -formed under sedation, and cytology was sugges -tive of HCC.Complete blood count results revealed a nonre -generative anemia (Hct, 35% [reference range, 40% to 59%] MCV, 68 fL [reference range, 62 to 77 fL]; MCHC, 33.8 g/dL [reference range, 33.0 to 36.1 g/dL]) and stress leukogram (absolute neutrophils, 7.79 X 109/L [reference range, 2.6 X 109 to 10.8 X 109/L]; absolute lymphocytes, 0.31 X 109/L [ref -erence range, 0.7 X 109 to 3.2 X 109/L]; absolute monocytes, 1.64 X 109/L [reference range, 0.1 X 109 to 1.1 X 109/L]). Serum chemistry abnormali -ties included increased concentrations of liver en -zymes ALT (3,587 IU/L; reference range, 18 to 108 IU/L), ALP (699 IU/L; reference range, 12 to 133 IU/L), and AST (317 IU/L; reference range, 16 to 51 IU/L).Treatment and OutcomeCase 1A standard ventral midline celiotomy approach was made. The abdominal exploration revealed a large mass associated with the left medial liver lobe extending into the hilus of the central divi -sion. Following intraoperative visualization, it was determined that to completely resect the recurrent mass, the central division and left medial liver lobe would need to be removed en bloc. Some dissec -tion of the fat overlying the right divisional hepatic duct was performed to identify this structure be -fore positioning the stapler. The right medial lobe, gallbladder, quadrate lobe, and left medial lobe were removed en bloc at their respective hilus with a vascular loading unit (TA-30 Vascular Loading Unit with DST Series Technology; Covidien LLC). Additional hemostasis was achieved with hemo -clips. Following resection, bile leakage from the right lateral hepatic duct near the junction to the common bile duct was noted and subsequently re -paired with a simple interrupted suture using 5-0 polypropylene suture. Prior to closure, the abdo -men was lavaged with warm, sterile saline solu -tion. The abdomen was closed in routine fashion via 3-layer closure. The dog recovered unevent -fully from the procedure. Histological examination Figure 1 —A—Transverse plane CT image of case 1’s hypoattenuating soft tissue mass with heterogeneous contrast enhancement. Note the metal attenuating staples along the left dorsal margin of the mass from the previous surgical resection. B—Transverse plane CT image of case 2’s hypoattenuating soft tissue mass with heterogeneous contrast enhancement (white ar -rows), occupying most of the liver at this level. Note the dorsal displacement and compression of the portal vein (chevron) by the mass. The caudal vena cava is not easily identified in this image due to compression. Win -dow width, 400 HU; window level 40 HU; 1.25-mm slice thickness; acquired with 120 kVp.Unauthenticated | Downloaded 10/08/23 06:32 AM UTC 3confirmed a diagnosis of HCC, indicative of local recurrence. Neoplastic cells extended to 2 mm of the surgical margin, which consisted of adjacent liver tissue, and were considered narrow but com -plete. The dog was seen for recheck examination 6 months following surgery by the referring veteri -narian. Liver enzyme elevation improvement (ALT, 88 IU/L [reference range, 8 to 65 IU/L]; ALP, 113 IU/L [reference range, 7 to 92 IU/L]) and lack of tumor recurrence were identified following chem -istry panel and abdominal ultrasonography re -check diagnostics.Case 2A standard ventral midline celiotomy approach was made. The abdominal exploration revealed a large mass associated with the right medial liver lobe. A small diaphragmatic incision was made to enable caudal retraction of the liver mass and permit improved visualization of adhesions to the diaphragm. The gallbladder and cystic duct were dissected from the right medial liver lobe using a combination of blunt dissection and a precise ves -sel-sealing system (LigaSure and ForceTriad Energy Platform; Medtronic). During dissection, the cystic bile duct was torn and was subsequently ligated us -ing 4-0 polydioxanone suture. The left and central division, along with the gallbladder, were removed en bloc at the hilus with a vascular loading unit (TA-55 Vascular Loading Unit with DST Series Technol -ogy; Covidien LLC). The papillary process of the caudate lobe was removed en bloc with a TA-30 due to congested appearance and concern for a com -promised blood supply. During surgery, significant blood loss resulted in hypotension (mean noninva -sive blood pressure, 40 mm Hg; reference range, 60 to 100 mm Hg) that warranted an intraopera -tive transfusion of 2 units of packed RBCs. The dia -phragm was closed with 4-0 polydioxanone suture in a simple continuous pattern. Air was evacuated from the thorax with a red rubber catheter, 3-way stopcock, and 60-mL syringe until negative pres -sure was achieved. The abdomen was closed in rou -tine fashion via 3-layer closure. The dog recovered uneventfully from the procedure. Histopathology of the liver sample confirmed a diagnosis of HCC. Neo -plastic cells extended to the margins of the excised hepatic mass, and monitoring for recurrence was recommended. The dog was reportedly seen for re -check examination 6 months following surgery by the referring veterinarian. Liver enzyme elevation improvement (ALT, 150 IU/L [reference range, 18 to 121 IU/L]; ALP, 357 IU/L [reference range, 5 to 160 IU/L]; and AST, 47 IU/L [reference range, 16 to 55 IU/L]) and lack of tumor recurrence were identified following chemistry panel and abdominal ultraso -nography recheck diagnostics.CommentsThis report describes surgical treatment for HCC via central and left division hepatectomies in 2 dogs. Massive HCC are typically treated with liver lobectomy, but these cases involved multiple lobes, due to either recurrence of disease or simply size and location of the primary tumor. Left and central divisional hepatectomies were required to remove all tumor-bearing segments in these dogs. Pro -longed survival times (> 1,460 days) are reported in dogs undergoing surgical resection of affected liver lobes.1 Reported recurrence rates of HCC are low, about 0% to 5.4%; therefore, surgical resection via liver lobectomy is the treatment of choice to remove tumor-bearing segments in their entirety.1 In comparison, dogs whose owners elect to pursue medical management, as opposed to pursuing sur -gery, for HCC have a median survival time of only 270 days.1 While case 2 had an incomplete resec -tion, the overall survival times in both dogs are ex -pected to be similar.1When multiple liver lobes are found to be in -volved, preoperative planning is required before sur -gical resection. The liver’s 3 subdivisions—left, central, and right—make up 44%, 28%, and 28% of the liver’s to -tal volume, respectively.2 Both the volume and func -tionality of the liver remnant need to be considered to prevent posthepatectomy liver failure (PHLF). While no uniform definition for PHLF exists, it is generally considered to include failure in 2 or more of the liver’s synthetic or excretory functions or clinical evidence of hepatic encephalopathy following hepatectomy.3 Nei-ther dog in this report showed signs of PHLF, as both had normal postoperative chemistry panels with re -solved elevated liver enzymes. In case 1, only 1 excre -tory function (total bilirubin) was impaired preopera -tively, but the hyperbilirubinemia resolved following surgical intervention.When performed as separate procedures, both left and central hepatectomy have been proven to provide successful clinical outcomes at both remov -ing the tumor and preserving patient liver function.4 Experimentally, young dogs, between the ages of 8 and 12 months, have tolerated massive hepatec -tomy, with up to 90% of hepatic mass resection, but no clinical cases have been reported with resection > 50% of total liver volume.3 Using previously reported liver lobe volumes, the total liver volume removed in case 1 and 2 was about 72%.2Extensive hepatic resections increase the risk of PHLF. Neither dog in this report showed signs of PHLF based on postoperative liver enzyme elevation resolu -tion and normal chemistry panel values. The limits for how much liver can be resected at 1 time are debated. When experimental extensive hepatectomy was per -formed in dogs by performing staged surgical proce -dures, resection of 95% of the dog’s total hepatic mass was possible because liver regeneration occurred dur -ing the waiting period of 6 to 8 weeks between pro -cedures.5 It should be noted that most of the resected liver consisted of the neoplastic mass in both dogs; therefore, it can be assumed that the amount of func -tional liver volume resected was far < 70%.Successful clinical outcome following both sin -gle-session central and left division hepatectomies has not been reported in small animals prior to this case report. Further studies are necessary to deter -Unauthenticated | Downloaded 10/08/23 06:32 AM UTC4 mine the largest hepatectomy limit achievable with -out inducing PHLF in a dog with and without preex -isting liver disease.AcknowledgmentsThe authors declare that there were no conflicts of interest.The authors thank Giovanni Tremolada, DVM, PhD, DACVS, for his edits on the manuscript.

Answer 22

As laparoscopy continues to grow in small animal medi-cine, the desire to engage with our smaller patients willrequire innovative responses. The difficulty in performingprocedures within the small working space of felinepatients inevitably discourages some surgeons but thesecomplexities can be overcome with smaller instrumentsand creativity. The use of the customized 3D printedcannulas in this report created an increase in workingspace of approximately 2 cm due to the shortened shaftlength. The body wall: 3DPC shaft length appeared to beapproximately 1:2 during use but future studies shouldbe performed to determine whether this length is themost appropriate for the majority of feline patients. Thisallowed for the surgeon to retract and dissect with lessinterference from the cannula thereby allowing easiermanipulation of instruments and intrabdominal tissuesand significantly shortened procedure times. While pro-cedure times are reduced as surgeons gain proficiency,in human medicine it requires at least 30 laparoscopicvertical sleeve gastrectomies before a surgeon can be con-sidered competent.38The author in this study only per-formed the procedure five times before the use of only3DPCs which suggests the customized cannulas did helpmeaningfully with procedure performance. The designand production time (24 +h) for the 3DPC in this reportdoes require preoperative planning but the benefits forpatients and surgeons still support continued research inthis field. Once devices have been designed initially, rede-signing or modifying them takes considerably less timeand batch production can generate an established stockof devices. These cannulas could be used for basic laparo-scopic procedures (ovariectomy, cystotomy) but the truebenefit would be during procedures that require instru-mentation with longer jaws (stapling, sterile sample bags)or intricate manipulations (gastrectomy, pancreatectomy,thoracoscopic procedures).The significant difference in instrument collisionsand cannula pullout are also a promising finding whenconsidering advanced procedures in smaller dogs andcats. When procedural frustration and time are reduced,procedures are more likely to be finished laparoscopicallyas opposed to being converted to a laparotomy. Whilethere have been many improvements to laparoscopicinstrumentation to allow for better approaches to smallerpatients including 3 mm telescopes and instrumentation,needle-scopes, and varying needle-related graspingdevices, continued expansion into new possibilities fordevices should be encouraged. Mammadov et al. investi-gated the creation of 3D printed cannulas and a retractorfor use in laparoscopic pediatric surgery and found theimplants durable and sterilizable.27The authors in thetwo studies assessing 3D printed cannulas also used theoriginal silicon leaflet valves from the inspiration trocaras we did in this study.27,34Both studies demonstratedadequate seal with this configuration which we con-firmed. In our study, two cannulas did leak from the bor-rowed silicon valve but this was at the instrument valveinterface not the valve port interface. These valves hadbeen resterilized many times before use in the procedure,which is common in veterinary medicine, leading to stiff-ening of the material and the leak.The only veterinary report on 3D printed laparoscopiccannulas in an experimental porcine model investigatedthe ability of the trocars to maintain pressure and theabdominal wall defect dimensions.34These authorsprinted ternamian (threaded) ports alleviating the needfor a trocar for insertion. As our port was more difficultto insert than commercially available ports with snug-fitting trocars, future work should be performed to assessdifferences between 3D printed port types and insertionpressures and incision dimensions. Even with thisthreaded design, the authors of that study discovered thatthe incision length and area for their cannulas wasgreater than the commercially developed cannulas. Theclinical relevance to that difference, while statistically sig-nificant, remains to be seen.The ability to 3D print various surgical instrumentsmay also allow for significant decreases in expense andmedical waste,39–42which is not only important inhuman medicine. The cost of equipment is acutely felt byveterinary practitioners and is not as easily passed on toclients as it is in the human surgical sphere. Not everypractice or institution can purchase every size or type ofminimally invasive equipment, therefore, customized3DPCs can give surgeons a flexible alternative to create acannula of any specific length or size while remainingrelatively cost effective. Approximate cost of print mate-rials per PLA prototype cannula was $0.30 while theapproximate cost of the dental resin print material percannula was $3.50. With the addition of the estimatedcost of consumables per cannula (e.g., resin tank, washsolution) of $0.75 per cannula, total cost per cannula isestimated at less than $5.00. These cannulas can bereused multiple times if needed just like the commer-cially available products due to their ability to be steril-ized. While there is a great range of cost with regards tothe printer itself depending on the type of material used,the current generation of the printer and post processingequipment used in this study retails for approximately$5000.00. This one time cost is less expensive than manylaparoscopic instruments and this machine can be usedfor other purposes as previously described. Our data con-firmed the results from previous report that sterilizationwith hydrogen peroxide sterilizer was effective before useBUOTE ET AL . 875 1532950x, 2023, 6, of the cannulas, but studies have determined plasma andsteam sterilization to also be effective.27,43Limitations for this study are predominately relatedto the cadaveric design, printing limitations, and the non-randomized study design. The printed trocars did notsmoothly fit within the cannulas which led to more diffi-culty with abdominal insertion. While the authors didnot find this particularly onerous and the live patientsshowed no indication of increased discomfort or inci-sional complications, continued improvement in the 3Dprinting design is underway. The use of commerciallyavailable silicon valves is another limitation seen in thisreport and others on 3D printed cannulas. This can beovercome as more flexible thermoplastic materialsbecome available on the market or possibly with the crea-tive use of surgical glove fingertips.44Another limitationof this study is that we did not evaluate the surface com-position and the effects of sterilization of our cannulas.While changes may be seen in the morphologic proper-ties of these cannulas, it is unclear if these deviationseffect safe clinical use of this equipment, therefore moreresearch is warranted. Our clinical patients recovereduneventfully from surgery and no incisional discomfortor complications were seen, encouraging our continueduse of these cannulas due to their benefits during surgicalprocedures.Lastly, there was not randomization with regards tothe types of cannulas used per procedure and there weretwo different port location configurations due to the useof the SILS port in two cases. As the invention of 3DPCsresulted from difficulties encountered during the processof surgical technique refinement a randomized studycould not be performed. As we progressed through thesurgical procedure rehearsals, we tried different cannulasto overcome encountered complications. The SILS portwas tested even though it can create difficulties with tri-angulation, as it has the benefit of allowing multipleinstruments of different sizes to be traded between thecannula sites. As we exchanged commercial cannulas for3DPCs and appreciated the improved surgical times andreduced complications we decided their sole use wouldlead to the best surgical outcome for our live patients. Arandomized controlled study evaluating a specific num-ber and type of commercially available cannulas and3DPC in feline surgeries is being pursued currently. Evenwith these limitations, this study demonstrates the possi-ble use of 3D printed devices in minimally invasive sur-gery which may increase the number and type of surgicalprocedures pursued in our small animal population.In conclusion, the use of 3DPCs was feasible andreduced surgical times, instrument collisions and cannulacomplications in this feline model and two live patients.3DPCs can be applied broadly across the minimallyinvasive surgical field in veterinary medicine to assistadvanced procedures in our smallest patients. These cus-tomized cannulas can be created in sterilizable, biocom-patible materials to be used in live patients potentiallyincreasing the number of minimally invasive proceduresperformed.CONFLICT OF INTERESTThe authors declare no conflict of interest related to thisreport.ORCIDNicole J. Buote https://orcid.org/0000-0003-4623-3582

Answer 23

The study aimed to clarify the clinical anatomy of theintermetatarsal channel, dorsal pedal artery, and perforatingmetatarsal artery; evaluate whether screws were placed atthe level of the mean intermetatarsal channel during PanTAand ParTA; and assess the subsequent incidence of plantarnecrosis. The principal blood supply to the plantar tissues ofthe canine pes is from the perforating metatarsal arterywhich supplies the deep plantar arch.3,4It has been hypoth-esized that this may be interrupted by direct drill or screwimpingement during plate application.2Through cadavericdissection, this study revealed the landmarks of the inter-metatarsal channel, and demonstrated that it is highlyvulnerable to damage during tarsal arthrodesis, with 92%of dogs studied having at least the ﬁrst metatarsal screwviolating the mean intermetatarsal channel position (100% ofParTA and 80% of PanTA cases).Despite the vulnerability of the intermetatarsal channel toscrew damage during arthrodesis, this study found that 92%of cases that had a screw placed at the level of the inter-metatarsal channel did not develop plantar necrosis. Theanatomy of the intermetatarsal channel in a shallow dorsalsulcus between metatarsals II and III is such that it is only atrisk when a screw either exits dorsally in this region ortraverses at the level of the perforating metatarsal artery.From radiographs, it is not possible to plot the course of thescrews in all planes; this study used the proximodistal screwposition as a predictor of risk to the intermetatarsal channel.Based on this information, the placement of screws 1 and 2Fig. 4 Box and whisker plot showing no difference in metatarsal screw position between cases with and without plantar necrosis ( p<0.05). X ¼mean. Horizontal line ¼median..poses the greatest risk of encroaching on the intermetatarsalchannel; whether this occurs or not will be in ﬂuenced byscrew angle, plate selection and screw length. ►Figs. 5 and6demonstrate how it is possible to avoid damaging the arterialblood supply and may explain the low incidence of plantarnecrosis despite almost universal screw placement in thisregion. It is also feasible that the low incidence of plantarnecrosis is due to sustained collateral blood supply in themajority of cases; damage to the dorsal pedal artery orperforating metatarsal artery may therefore be possiblewithout subsequent development of plantar necrosis. Anec-dotally, the authors have subsequently observed damage tothe perforating metatarsal artery during elective ParTA fornon-traumatic calcaneoquartal instability, without develop-ment of plantar necrosis. However, minimal swelling oc-curred, and collateral circulation appeared uninterrupted.Conversely, the authors have also observed ischaemia neces-sitating pelvic limb amputation following ParTA for traumat-ic calcaneoquartal/tarsometatarsal luxation; the caserequired tension-relieving incisions, and postoperative dis-section revealed thrombosis of the dorsal pedalartery secondary to screw impingement.Plantar necrosis has previously been associated withmedial plating; however, in our study, plantar necrosisoccurred only in lateral ParTA cases, with 13% of laterallyplated cases developing plantar necrosis.2In a previousstudy, plantar necrosis was reported to occur in 33% ofmedial plates and 4% of lateral plates.2There is thereforeno consistent evidence that plantar necrosis is associatedwith plate laterality. Tarsometatarsal joint debridement andtight closures have also been previously postulated as riskfactors for plantar necrosis.1,2Interestingly, all three casesthat developed plantar necrosis in this study had tension-relieving incisions and traumatic tarsometatarsal joint inju-ries. Tarsometatarsal joint luxation presents an opportunityfor shearing injuries to occur to the dorsal pedal artery at thetime of injury, and damage may also occur during tarsome-tatarsal joint debridement. A recent study of 30 dogs under-going PanTA reported no cases of plantar necrosis.1Anesi andcolleagues postulated that this was due to the care they tookwith tarsometatarsal joint debridement, debriding only me-dially and ventrally, and burring osseous prominences toreduce skin tension.1It is notable, however, that none of thedogs in that study underwent arthrodesis due to tarsome-tatarsal joint injury. Conversely, all of the plantar necrosiscases in this study and 67% of cases in Roch ’s study hadsubluxation of the tarsometatarsal joint.2Anecdotally, thetarsometatarsal joint region is often the tightest region toclose; therefore, swelling in this region may increase skintension and the risk of a postoperative biological tourniqueteffect. The number of tarsometatarsal joint luxation caseswas too small to perform statistics on; however, based on ourpreliminary data, the authors postulate that damage to thetarsometatarsal joint may be a risk factor in the aetiopatho-genesis of plantar necrosis, and future studies should look toinvestigate this.Further studies are needed to identify all the contributoryfactors leading to plantar necrosis, but the authors theorizeFig. 5 Dorsoplantar illustration of the distal pelvic limb showing aproposed safe corridor approach for the proximal two medial andlateral metatarsal screws, avoiding the intermetatarsal channel andthe perforating metatarsal artery..that plantar necrosis is unlikely to occur due to isolateddamage to the perforating metatarsal artery. However, untilfurther angiographic studies can clarify this, it appearsprudent to take particular care with placement of screws 1and 2 when performing a ParTA with a lateral plate and withscrew 1 when performing a PanTA with a medial plate. Thisstudy shows that the intermetatarsal channel is expected tolie in the most proximal 25% of metatarsal III in 95% of cases.Using the dimensions recorded in this study and a calibratedradiograph, the surgeon can calculate the expected lengthand position of the intermetatarsal channel in their patient.Intraoperatively, the dorsal pedal pulse can also be palpatedbetween metatarsals II and III to aid in con ﬁrming thelocation of the intermetatarsal channel.►Figs. 5 and 6outline the proposed safe corridor to the metatarsal regionto reduce the probability of damaging the interosseous partof the perforating metatarsal artery. The distal extent of theintermetatarsal channel is where the perforating metatarsalartery passes between the metatarsals and is most at risk ofscrew perforation, being relatively immobile and thereforevulnerable to damage as it passes interosseously. Therefore,with a lateral approach, surgeons are advised to place screw1 proximally and plantarly, away from the dorsally situatedintermetatarsal channel and the perforating metatarsal ar-tery. Furthermore, when placing screw 2, the transcortex ofmetatarsal III should not be perforated with either the drillbit or the screw because the perforating metatarsal arterywill be in this region. Further screws can be placed routinely,below 25% of the length of MTIII. For a medial approach,particular attention should be paid to the placement of theﬁrst metatarsal screw, angling it proximally and plantarly toavoid traversing the distal interosseous perforating metatar-sal artery position and to keep it below the intermetatarsalchannel dorsally. The 2nd, 3rd and 4th metatarsal screws canbe placed routinely below 25% of the length of MTIII. How-ever, angled approaches are only achievable for non-lockingor polyaxial screws.There are several limitations to this study. Due to theretrospective nature of the study, the author ’s ability toevaluate surgical decision-making or which joints weredebrided was constrained by the accuracy of clinical records.In addition, the intermetatarsal channel position was found tolie in the proximal 25% of MTIII in 95% of cases; however, therewas one outlier at 32.4%. In the clinical setting, there maytherefore be a low risk of interrupting the intermetatarsalchannel beyond the proximal 25%. Furthermore, the samplepopulation was heterogenous, and the reasons for arthrodesisvaried. Tarsal arthrodesis is an uncommon surgery and there-fore the sample size is relatively small; it should therefore benoted that type II statistical errors are possible.Additional studies investigating the timing betweeninjury and surgery are recommended. Swelling caused bythe primary injury could be a factor in the constriction ofthe collateral vessels. In human medicine, current recom-mendations regarding timing of surgery vary widely, al-though there is little argument that oedema impairs tissuemicrocirculation and perfusion, which are critical to thecellular processes of healing.9–11Therefore, until furtherresearch is available, the authors recommend postponingsurgery until swelling subsides. The use of negative pres-sure wound therapy in the prevention and treatment ofplantar necrosis should also be explored, as it has beenFig. 6 Illustration showing transverse sections ( AandB) through the metatarsals (MT) at levels indicated by the accompanying diagram of thedistal pelvic limb, demonstrating the safe corridor to the proximal MT region, avoiding the intermetatarsal channel and the perforating MTartery. ( A) Proximal extent of the intermetatarsal channel. ( B) Interosseous segment of the perforating MT artery. Red circle ¼dorsal pedal arterywithin the intermetatarsal channel. Red rectangle ¼perforating metatarsal artery..shown to promote wound contr action with diminishedtensile forces, decrease oedema, remove excess ﬂuid andstimulate blood ﬂow.12–15In conclusion, the vulnerability of the dorsal pedal arteryand perforating metatarsal artery during tarsal arthrodesis ishighlighted. Although it is not possible to con ﬁrm thatdamage to the dorsal pedal artery and perforating metatarsalartery is the primary cause of plantar necrosis, these datasupport the notion that damage to this region could, inconjunction with collateral circulation occlusion, contributeto the aetiopathogenesis of plantar necrosis. The low inci-dence of plantar necrosis, despite this vulnerability, reinfor-ces the theory that plantar necrosis is unlikely to result fromisolated damage to the dorsal pedal artery or perforatingmetatarsal artery. Therefore, the authors propose that dis-ruption of both the principal and collateral blood supply isrequired for plantar necrosis to occur. Consequently, untilprospective angiographic studies in cases of plantar necrosisare available to more accurately clarify the potential fordamage during screw placement, it is advisable to be cau-tious with screw angulation in the region of the intermeta-tarsal channel and perforating metatarsal artery.

Answer 24

In the present case, spinal cord compression resulted from both a C4- C5 intervertebral protrusion disc and an OCD frag -ment originating from the cranial C5 endplate. This is the first described case of OCD of a cervical vertebral endplate combined with disc protrusion.Cases of vertebral osteochondrosis have been reported in the literature, especially concerning cervical facet joints or FIG 6. Sagittal section of the cervical spine after ventral decompression through a C4- C5 ventral slot. The majority of the C5 bone fragment has been surgically removed, with a small residual portion remaining (green arrowhead). Cr Cranial, Cd Caudal, Ds Dorsal, Vt VentralFIG 7. Transverse section through the cranial part of C5 after surgery with small residual part of the bony element. Ds Dorsal, L Left, R Right, Vt VentralFIG 8. Histological section of the removed bone fragment stained with H&E (×6.3). Fibrillation of cartilage matrix (star). Note the partial loss of chondrocytes, presence of only a few scattered isolated chondrocytes (arrows)FIG 9. Histological section of the removed bone fragment stained with H&E (×10). Fibrillation/loss of basophilia of the cartilage matrix (star) with disorientation of the chondrocytes. Note the cluster of hypertrophied chondrocytes (reactive change) (arrow) 17485827, 2023, 12, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jsap.13653 by Vetagro Sup Aef, Wiley Online Library on [24/12/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseA. Thibault et al.Journal of Small Animal Practice • Vol 64 • December 2023 • © 2023 British Small Animal Veterinary Association. 804lumbosacral endplates. The first one concerned facet joint anomalies at C5/C6 and C6/C7 in Great Danes and at C2/C3 in Borzoi and are part of cervical vertebral malformation– malarticulation in cervical spondylomyelopathy (Hedhammar et al. 1974 , Schöllhorn et al. 2012 ). Lumbosacral endplates OCD is mainly reported at the lumbosacral junction, espe -cially in German Shepherds (Hanna 2001 , Mathis et al. 2009 ). Isolated cases of osteochondrosis have been described in the C2- C3 and T4- T5 endplates in an eight- month- old male Pointer and in the T7 endplate of a nine- month- old male Bernese Mountain dog (Alexander & Pettit 1967 , Bartels et al. 1970 ). In these sporadic cases affecting the cervical or tho -racolumbar spine, no cross- sectional imaging was performed, making it difficult to compare with our case, particularly with regard to spinal cord compression or the concomitance of a disc disease. However, one of the dogs was necropsied and a T4- T5 spinal cord compression was revealed (Bartels et al. 1970 ). For the second dog, surgery was performed (Alexander & Pettit 1967 ). The location (ventral part of the endplate of T7) made the hypothesis of medullary compression unlikely, even if a modification of the disc leading to its extrusion/protrusion was possible. In these two cases, the clinical signs (neck pain in the first case, hyperthermia and neck pain in the second) did not correspond to the location of the lesions (thoracic vertebrae). On the contrary, in lumbosacral OC, static or dynamic compression of the spinal cord or emerg -ing nerves is frequent and often requires decompressive sur -gery (Hanna 2001 ). The case reported here is, therefore, more similar to the described cases of lumbosacral OC with com -pression related to the free fragment and the intervertebral disc protrusion. However, the instability or even concomitant subluxation reported in lumbosacral OC (21/32 cases) was not observed in this case (Hanna 2001 ).Disc protrusion could be induced by various factors. Although not observed here, a similar instability reported during lumbosa -cral OC was possible; it could promote a progressive protrusion or extrusion of the disc. Other hypotheses included the structural disruption of the disc/endplate interface. This leads to altered mechanical stresses but also to abnormal nutrition of the disc. Both of these may contribute to premature degeneration of the disc.Another hypothesis is that disc degeneration is independent of the OCD lesion. Chondrodystrophic breeds, including the French bulldog, are predisposed to early disc degeneration with disc calcification (Murphy et al. 2019 ). However, even if CT scan is highly sensitive in detecting disc calcifications, its absence is not sufficient to conclude disc degeneration (Stigen et al. 2019 ). Ideally, this could have been determined with an MRI exam or, alternatively, histological analysis of the disc. This analysis was not performed: as this was a disc protrusion, most of the disc was removed by speed- burring, making it difficult to take a quality histologic sample.The surgical technique used in this case corresponds to a clas -sical ventral slot, with removal of the degenerated bone fragment. In the case of lumbosacral OC, two different surgical techniques can be performed depending on whether the compression is static or dynamic. In case of static compression, only decompres -sive surgery (dorsal laminectomy) is performed. On the contrary, in case of dynamic compression, a distraction- fusion technique is added to the previous procedure (Hanna 2001 ). Similarly, in cervical spondylomyelopathy with dynamic compression, it is generally accepted that a technical distraction- fusion is recom -mended. In our case, CT or radiographic views with stress posi -tions were not performed to show dynamic compression. These exams were not performed, as the French bulldog is not a breed predisposed to cervical instabilities, the C4- C5 location is not a preferential site, and there was no evidence of local instability. The hypothesis of concomitant instability and therefore the need for a distraction- fusion technique appeared unlikely. The marked clinical improvement and the absence of pain for the dog dur -ing the follow- up suggest that this additional procedure was not essential in this case.The removal of the fragment was incomplete. The strong adhesions as well as the poor visibility provided by the ventral slot made its removal complicated and risky. In contrast to lum -bosacral OC, complete removal of the fragment appears to be a surgical challenge.The clinical outcome of our case is not perfect with the per -sistence of a slight limp. This limp could be due to residual spi -nal cord compression. The residual portion of the fragment may be the origin of this compression, however, the lateralization is rather to the right and the limp persists slightly to the left. In the absence of pain, the owners did not wish to investigate further, in particular by performing an MRI of the area. In the case of lateralized material or nerve root entrapment, a lateral or dorsal approach could improve visualisation and treatment of the lesion.This case illustrates an OCD of the cranial endplate of C5 concomitant with spinal cord compression in a French bulldog. This anomaly, not described in the cervical spine yet, was treated by ventral slot and removal of the fragment. The outcome was good in this case.AcknowledgementsThe authors thank Yvonne McGrotty for her valuable comments on the manuscript.Author contributionsAlexandre Thibault: Conceptualization (equal); project admin -istration (lead); visualization (lead); writing – original draft (lead). Martin Hamon: Conceptualization (equal); supervision (supporting); writing – review and editing (equal). Renaud Jossier: Resources (equal); supervision (supporting); writing – review and editing (equal). Bérengère Wyrzykowski: Resources (equal); supervision (supporting); writing – review and edit -ing (equal). Philippe Haudiquet: Conceptualization (equal); resources (equal); supervision (lead); writing – review and edit -ing (equal).Conflict of interestNone of the authors of this article has a financial or personal relationship with other people or organisations that could inap -propriately influence or bias the content of the paper. 17485827, 2023, 12, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jsap.13653 by Vetagro Sup Aef, Wiley Online Library on [24/12/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseOsteochondritis dissecans of vertebral endplateJournal of Small Animal Practice • Vol 64 • December 2023 • © 2023 British Small Animal Veterinary Association. 805

Answer 25

In the 10-year period captured in the present study, 1 of 98 (1.02%) cases of dogs undergoing on -cologic maxillectomy or mandibulectomy required administration of blood products due to severe in -traoperative hemorrhage. Intraoperative hemor -rhage has been consistently reported as the most common complication during caudal maxillectomies, with transfusion rates ranging from 30% to 50%.2,4,8,9 These observations, although inconsistent with our findings, are unsurprising given the proximity of the osteotomy sites to the maxillary artery and its prom -inent branches. The variety of surgical procedures included represented the full spectrum of described surgical techniques with the explicit exclusion of total and extended subtotal mandibulectomy cases.5,30,31 Additionally, patient age, size, breed, tumor type, and tumor location described in the present data set were comparable to previous studies.1,2,4,5,8 While di -rect comparison to previous studies is not ideal, the variables noted here are similar to previous reports, with the exception of the cutting instrument. There -fore, the notably low intraoperative hemorrhage rate observed in this study was likely aided by the use of a piezoelectric surgical unit. However, other factors such as appropriate case selection, familiarity with the anatomy, diagnostic imaging, surgical planning, and skill all play an important role in the outcomes of these challenging surgeries.The single patient that received a blood transfu -sion was 1 of 13 (7.69%) dogs that underwent a caudal maxillectomy. The anesthetic record demonstrated paradoxical bradycardia. While this deviates from the classic signs of tachycardia and hypotension typically seen in cases of acute hemorrhage, 1 possibility for Surgical location No. Median Range IQRMaxillectomy 39a 2.73 0.83–6.58 1.75 Unilateral rostral 16 2.13 0.83–4.98 1.46 Bilateral rostral 8 2.08 1.00–3.95 1.19 Central 3 2.08 1.25–5.70 4.45 Caudal 12 3.94 2.33–6.58 1.62 Total 0 — — —Mandibulectomy 53b 2.41 0.58–5.58 1.5 Unilateral rostral 11 2.33 1.50–4.25 0.75 Bilateral rostral 25 2.33 1.00–5.50 1.66 Rim excision 6 1.96 0.58–2.66 0.75 Caudal 0 — — — Subtotal 11 3.25 2.00–5.58 1.33aTwo dogs did not have surgical time recorded. bFour dogs did not have surgical time recorded.Table 1 —The range of surgical times by anatomical lo -cation, demonstrating similar surgical times between maxillectomy and mandibulectomy and significant in -crease in surgical time for the most caudal procedures. Unit of measurement is in hours.Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 08/30/23 11:59 AM UTC 5this change is myocardial hypoxia as a result of acute hypovolemic anemia. This would explain the brady -cardia and ventricular beats as early indicators for the need of packed RBCs.For this study, careful surgical planning and use of piezoelectric surgery were adequate in avoiding significant hemorrhage. Prior reports have recom -mended temporary or permanent carotid ligation, which is not without its own inherent risks and com -plications, including hemorrhage, prolonged surgical time, and trauma to the vasosympathetic trunk, re -current laryngeal nerve, and internal jugular vein.11 Postoperative sequelae can also include hematoma formation, retinal damage, and cerebral ischemia.11The most commonly used bone-cutting instru -ment for maxillectomy and mandibulectomy pro -cedures has traditionally been the oscillating saw, although other rotary instruments as well as an os -teotome and mallet have also been reported.2,4,8,9 The power osteotomy instruments convert electric or air-driven energy into mechanical energy that creates heat at the cutting surface, increasing risk of osteonecrosis and local tissue damage.15,21 Typical -ly, bone-cutting burs used in rotary handpieces are thicker compared with piezoelectric tips, increasing the volume of bone lost during osteotomies and in -creasing the torque and drilling force needed to be effective.21 These factors limit the design and preci -sion of the osteotomy, are indiscriminate in the dam -age inflicted to soft tissues in the vicinity, and reduce tactile feedback to the operator.2,21,25,33,34In human medicine, oral surgeons use piezoelec -tric units to reduce the risk of intraoperative hemor -rhage for many types of delicate maxillofacial pro -cedures.12,16,20,26,35–40 Piezoelectric surgery utilizes ultrasonic micro-oscillations at frequencies that cut mineralized tissues and spare soft tissues.20,26–28 As a result, piezoelectric surgical handpieces do not re -quire much operator pressure for effect, allowing for improved ergonomics, high tactile sensitivity, and preservation of fine motor control of the handpiece, which make this useful for cutting bone intimately as -sociated with nerves and vessels such as that of the jaw.15,17,25,29 Modern piezoelectric units also include a cold LED light to enhance surgical field visualization and continuous sterile saline irrigation that rinses de -bris from the surgical site, avoids overheating, and provides a solution for cavitation, which cauterizes small vessels and provides a bactericidal effect.15,26 Piezoelectric tips are narrow and come in various angles and lengths allowing for a variety of osteot -omy designs, including semilunar and deeply angled cuts.21,35,41 These factors allow for precise bone cut -ting, reduced soft tissue damage, increased visibility, and sterilization of the surgical site.3,14,16,26,36,42–46Histomorphological studies have demonstrated that piezoelectric surgery results in increased lo -cal expression of bone morphogenic proteins and transforming growth factor as well as decreased inflammatory cytokines such as interleukin 1β for better bone healing compared with conventional surgery.18,21,26,38,47 Human studies19,29,48 describe improved healing with up to 50% less postoperative swelling and patients requiring up to 50% less postop -erative analgesia when osteotomies were performed with a piezoelectric unit compared with when they were performed with conventional oscillating saws.One cited disadvantage of piezoelectric surgery is relatively increased surgical time, with 1 study re -porting that osteotomies in hard or cortical bone take up to four times as long as traditional osteoto -mies.12,13,15,41,49 However, a human medical study41 comparing conventional instrumentation with piezo -electric surgery for impacted third premolar extrac -tion found that the gap in surgical duration closed as operators gained experience with piezosurgical units, eventually reaching parity. Moreover, any prolonga -tion of surgical time with a piezotome is arguably off -set by the benefits associated with the lack of severe hemorrhage, reduced costs and risks of blood prod -uct administration, and improved surgical outcome.When evaluating surgical time in the current co -hort, both bivariant analysis and multivariable linear regression found no significant difference between maxillectomies and mandibulectomies; however, surgical time for caudal surgeries was significantly longer than that of more rostral surgeries. This find -ing is expected, given that the complexity of the anatomy caudally necessitates more delicate dissec -tion, careful osteotomy, and closure.Limitations for this study are consistent with its retrospective nature. For example, case controls, where a separate cohort of patients would have un -dergone the same procedure using different cutting instruments, would have been ideal. Given that cases were collected from a teaching hospital setting over a period of time, the skill level of the multiple opera -tors varied, and this would likely have had an impact on surgical time. To compensate, strict inclusion cri -teria were used. Future studies using a prospective approach should be considered to best delineate complication rates when all variables, other than the cutting instrument, are kept consistent.Statistical analysis showed that maxillectomy procedures were more likely to lead to complications within the first 24 hours postoperatively than mandib -ulectomies. However, this was not the case at 2 weeks postoperatively. The complications noted within the first 24 hours were mild and largely self-limiting. When complications at the 2-week mark were as -sessed, caudal procedures were found to be more likely to lead to complications. This was particularly true for caudal mandibulectomies, as they sometimes resulted in significant mandibular drift necessitating treatment of the ensuing occlusal trauma. Interest -ingly, surgical site dehiscence has previously been reported as being the most common complication associated with maxillectomies, especially for caudal procedures; in contrast, the most common sequelae in the current study included lip entrapment, swell -ing, and self-limiting epistaxis, with no surgical site dehiscence reported.1,4 Eight of 57 cases (14.04%) un -dergoing mandibulectomy had small areas of surgical site dehiscence that did not require further surgical intervention. It is difficult to discern the exact reasons for lack of dehiscence in the maxillectomies included Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 08/30/23 11:59 AM UTC6 in this study. However, a combination of careful surgi -cal planning, good technique, and appropriate instru -mentation likely contributed.Results of this study show that intraoperative hemorrhage requiring the use of blood product dur -ing or immediately after a maxillectomy is rare when using a piezoelectric unit to perform osteotomies and is much lower than that previously reported. This study also corroborates the results of previous stud -ies that indicated intraoperative hemorrhage is rare for mandibulectomies.AcknowledgmentsThe authors have nothing to declare.

Answer 26

To the authors’ knowledge, this is the first feline case series of salivary gland adenocarcinoma of minor sali -vary gland origin. Diseases of the salivary glands are various and include inflammatory, obstructive, ischemic and neoplastic processes.2 A study of 245 cases of salivary gland disease in dogs and cats found that the major sali -vary glands are usually affected by malignant neoplasia, sialoadenitis, sialocele and salivary gland infarction.4Figure 3 Surgical closure in patient 4 after performing an excisional biopsy of the right mandibular buccal mucosal massFigure 4 Neoplastic cells arranged in acini, tubules and solid sheets. The neoplastic cells are polygonal to cuboidal with round to oval nuclei. The lobules of neoplastic cells are supported by a collagenous stroma, and there are occasional central areas of necrosis (hematoxylin and eosin, 20× )Figure 5 Patient 1 post mortem, on dorsal recumbency, with regrowth of the left mandibular buccal mucosal mass extending towards the ventral aspect of the mandible; 1730 days after excisional biopsyFigure 6 Post-mortem radiograph of patient 1 showing diffuse bilateral pulmonary nodules involving all lung segments without airspace consolidation or atelectasis. Differential diagnosis favoring metastatic diseasePrimary neoplasms of major (parotid, mandibular, sublingual, zygomatic) and minor (palatine, lingual, labial, gingival) salivary glands are infrequent in ani-mals.19–21, 22 Adenocarcinoma is the most common type of malignant salivary gland tumor in animals, with a reported 39% rate of lymph node metastasis at the time of diagnosis.10Historically, the distinction between minor and major salivary glands has not been well established in the vet -erinary literature23 and some of the definitions have var -ied depending on the number of ducts and size/amount of glandular tissue. Owing to the similar histopathologica 6 Journal of Feline Medicine and Surgery structures, documenting the anatomical site of the biopsy, as well as providing a substantial biopsy sample, can help identify these tumors as originating from minor vs major salivary gland tissue. In a more recent study, the precise location of salivary gland tumors in the majority of feline cases, 16/20 (80%) cases, was undetermined owing to the lack of a specific location of the tumor.24Both the major and minor salivary glands comprise tubules/ducts and are commonly differentiated depend-ing on the complexity of the tubuloacinar glands. This is currently an accepted classification albeit there is continued debate about the correct way to classify these lesions. Major salivary glands are categorized as compound tubuloaci-nar glands since they are branched with a more complex system of ducts and acini.21 Minor salivary glands are sim -ple tubuloacinar glands measuring 1–2 mm in diameter.21Besides the four pairs of major salivary glands – parotid, sublingual, mandibular and zygomatic – cats also have minor salivary glands on the lingual and labial aspects of the mandibular first molar tooth, referred to as lingual molar and labial molar glands (or buccal glands).23,25 The buccal molar salivary gland empties into the buccal oral cavity by several small ducts.26 The membranous molar pad just lingual to the mandibular first molar tooth has numerous small salivary gland openings directed towards the tongue.27 The minor mucosal labial glands in cats are scattered throughout the submucosa of the lips, with numerous small excre-tory ducts.26 Cats also have minor mucosal buccal glands, which similarly have numerous small excretory ducts.27Histological changes with adenocarcinoma of the salivary gland can present as neoplastic epithelial cells forming acini, ducts, trabeculae, nests or solid sheets.2 Tumor cells can have different morphologies such as cuboidal, columnar, polygonal, clear, mucinous, oncocy -toid and plasmacytoid.21 The histopathology of the cats of this series showed acini, tubules and duct-like struc-tures. The histopathology findings combined with the location of the oral masses support the conclusion that salivary adenocarcinoma was arising from the labial (buccal) molar minor salivary gland in all four cats.In human medicine, the primary treatment of salivary gland tumors involves surgical excision, with radiation reserved for inoperable masses or adjuvant therapy after incomplete removal.28 In a recent study of feline major and presumed minor salivary gland carcinoma treated with radiotherapy after surgical excision of the primary tumor, the role of radiation therapy was unclear and its outcome was variable.6 The survival times of our study were an average of 980 days for cats with excisional biop -sies with clean ( >5.0 mm) margins (patients 1, 2 and 4), and 210 days for patient 3 which had palliative surgery performed. The survival times in our study surpass previous survival rates in the study by Hammer et al,10 where cats with adenocarcinoma in both major and minor salivary glands, with variable treatment (surgery alone, surgery and radiation, or surgery and chemotherapy), had a median survival time of 516 days, regardless of treatment type. These results suggest that complete, aggressive resection of adenocarcinoma of minor salivary gland tissue could potentially offer an increased survival time and decreased morbidity in cats.Owing to the small number of cases in our study, no conclusions can be made regarding risk factors for minor Table 4 Survival data for feline patients after oral surgeryPatient Type of biopsyMargins Follow-up (days)Time to local progression (days)Time to distant metastasis (days)Median survival rate (days)Comments1 Excisional Clean: caudal = 6 mm wide; rostral = 3 mm wide; deep = 3 mm wide60, 280, 910, 1730850 280 1730 Mass had extended towards the ventral aspect of the left mandible (Figure 5)2 Excisional Clean: buccal mucosa = 1.9 mm; caudal soft tissue = 8.0 mm9, 16, 25, 36910 N/A 910 N/A3 Surgical debulkingNo clean margins 14 210 N/A 210 Further follow-ups performed via telephone4 Excisional Narrow: mucosal = 1.7 mm; haired skin = 1.8 mm; deep = 0.1 mm14 120 N/A 180 Further follow-ups performed via telephoneN/A = not applicable; mm = millimetersMorgado Laureano et al 7salivary gland adenocarcinoma. In a previous study in 2001, Siamese or Siamese-cross cats represented 30% (9/30) of affected cats with salivary gland neoplasia, indicating a possible breed predisposition.10 In a more recent study of 56 dogs and 24 cats diagnosed with sali -vary gland neoplasia, a feline breed predilection was not determined.24 In the 2001 study, a 2:1 predilection ratio for male cats was found in 30 cats with salivary neopla -sia.10 In the current study, the mean age of cats diagnosed with salivary gland adenocarcinoma was 11 years (range 9–15). These results are similar to those of the 2001 previ -ous study in which the median age for affected cats with salivary gland neoplasia was 12 years.10The retrospective nature of this case series resulted in limitations in the information able to be obtained and evaluated. Minor salivary gland tumors are less frequently reported than major salivary gland tumors,24 and additional data are necessary to determine the pres -ence of metastatic disease at the time of initial diagno-sis. Metastatic disease occurred in 2/4 cats of this study (mandibular lymph node in patient 3 and pulmonary metastasis in patient 1). This supports the previous lit-erature, which found that salivary gland adenocarcinoma has the potential to metastasize and thus recommends preoperative staging.10,29The prevalence of salivary gland adenocarcinoma of minor salivary glands is low, representing only 4.7% of all caudal oral masses documented over a 14-year period. Other differential diagnoses for cats with caudal labial buccal mucosal mandibular masses should be consid-ered. Feline chronic gingivostomatitis can present with generalized or localized areas of ulceration or prolifera -tion on the alveolar and buccal mucosa of the caudal oral cavity.30,31 A focal proliferative mass-like lesion of the caudal buccal mucosa in cats, referred to as a pyogenic granuloma, is a chewing or traumatic reactive lesion (inflamed granulation tissue).32,33 Pyogenic granulomas most often occur on the mucosa that is buccal and some -times distal and/or lingual to a mandibular molar tooth.34 Additional granulomatous inflammatory lesions can also develop secondarily to allergies, chronic infection and even embedded foreign material.ConclusionsThis retrospective case series describes the survival times of four cats with minor salivary gland adenocarcinoma treated with either wide excisional resection or pallia -tive surgery. The survival time was greater for these cats compared with previously reported literature. Based on this current case series and a literature review over the past four decades, we suggest that regional control with wide excisional biopsy can increase the survival time and quality of life in cats presenting with adeno-carcinoma of minor salivary gland origin. Salivary gland neoplasia should be a differential for masses located in the caudal labial buccal mandibular mucosa of a cat. Further research is necessary in order to identify other treatment options, such as radiation therapy for feline patients with large and invasive primary tumors that do not qualify as surgical candidates or have had incomplete margins obtained.The primary cause of death in the cats in this study was from local recurrence rather than distant metastasis. Yet, our study supports previous reports of metastatic potential of minor salivary gland adenocarcinoma in cats,5 in particular to the regional lymph nodes and pulmonary parenchyma as noted in two cases (patients 1 and 3) in this study.

Answer 27

The results of this retrospective study suggest that cats undergo -ing TET excision have a good long- term survival and cats with a lower Masaoka- Koga stage may live longer after surgery than those with a more advanced disease stage.FIG 1. Kaplan- Meier survival curve for cats with Masaoka- Koga stage I and II versus stage III and IV thymic epithelial tumours 17485827, 2024, 1, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jsap.13675 by Vetagro Sup Aef, Wiley Online Library on [19/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseThymic epithelial tumours in catsJournal of Small Animal Practice • Vol 65 • January 2024 • © 2023 The Authors. Journal of Small Animal Practice published by John Wiley & Sons Ltd on behalf of British Small Animal Veterinary Association.53 TET is an uncommon disease and cats typically present with respiratory signs attributable to the presence of an intrathoracic mass or due to associated paraneoplastic syndromes (Robat et al., 2013 ). It is worth noting that 11% of cats in this popula -tion had an incidentally identified cranial mediastinal mass.In this study nine cats were diagnosed with a paraneoplastic syndrome including lymphocytosis, myasthenia gravis, exfolia -tive dermatitis and ionised hypercalcaemia. Studies in dogs have suggested that these could negatively affect outcome (Garneau et al., 2014 ) however, due to the low number of affected cats, this could not be evaluated in the present study.Up to 40% of human patients with TET have a concurrent neoplasia and 27% of dogs with TET had a second non- thymic tumour at the time of the TET diagnosis with another 14% developing another neoplasm during the follow- up period (Robat et al., 2013 , Thongprayoon et al., 2013 ). Robat et al. (2013 ) reported the presence of a second non- thymic tumour at the time of TET diagnosis was associated with a significant decrease in survival time, whereas no negative influence on survival time was noted if another tumour developed later. In the present study population only one cat had a concomitant maxillary neoplasia; however, complete staging was not performed in all cats and con -current neoplasms could have been missed. During the follow- up period only four cats developed a non- thymic neoplasia but it remains uncertain if TET could increase this risk.In this study cats that underwent surgery via median sternot -omy had a perioperative mortality of 11%, which is the same as Zitz et al. (2008 ) but lower than the 22% reported by Gar -neau et al. (2014 ). In those cats not surviving to discharge where Masaoka- Koga stage system could be applied, an advanced dis -ease stage (III to IV) was found in all of them. This likely reflects a more invasive tumour behaviour and difficult excision in those cases and may prompt the clinician to inform clients of a possible increased risk of perioperative complications or to consider alter -native treatments ( e.g. radiotherapy) instead. It is worth noting that cats that died in the perioperative period were excluded from the survival analysis and this should be taken into consideration when interpreting the survivals reported as it could have induced survival bias.For incompletely resected or non- resectable tumours, a multi- modal treatment approach may need to be considered (Zitz et al., 2008 , Rohrer- Bley et al., 2018 ). In this study, radiation therapy resulted in a PR in two cats and CR in another. Our find -ings are consistent with the limited available studies (Kaser- Hotz et al., 2001 , Smith et al., 2001 , Rohrer- Bley et al., 2018 ); one previous paper described the successful reduction in tumour size in three cases of suspected feline TET with a radiation protocol using 18 Gy over three fractions (Kaser- Hotz et al., 2001 ). Of those, one cat was well controlled for 4 years before recurrence happened (Kaser- Hotz et al., 2001 ). A second retrospective study assessed the use of radiation therapy for seven cats with TET, using a variety of protocols (ranging from daily to weekly treat -ments) and total doses of 15 to 54 Gy administered. The response Table 4. Simple logistic regression results determining factors associated with survival time after surgical intervention of thymic epithelial tumours in catsLogistic regression SurvivalOR 95% CI P valueAge 0.96 0.78 to 1.18 0.743Purebred 0.58 0.15 to 2.17 0.425Gender 1.27 0.38 to 4.23 0.693Bodyweight 1.40 0.77 to 2.55 0.269Duration of clinical signs 0.90 0.77 to 1.05 0.212Respiratory signs 1.68 0.45 to 6.25 0.432Paraneoplastic syndrome 0.25 0.03 to 1.98 0.290Cystic appearance 6.49 1.38 to 30.50 0.018Tumour diameter 1.16 0.98 to 1.39 0.080Pleural effusion 2.85 0.89 to 9.08 0.076Masaoka- Koga stage 4.66 0.13 to 16.02 0.015Histological diagnosis (thymoma versus carcinoma)0.40 0.10 to 1.48 0.170Capsular invasion 0.88 0.22 to 3.53 0.860Mitotic count 0.80 0.33 to 1.91 0.626Complete excision 0.47 0.11 to 1.89 0.292Recurrence 2.65 0.80 to 8.72 0.109OR Odds ratio, CI Confidence intervalReference category used in logistic regression. Variables highlighted in bold qualified for inclusion in the multiple regression analysis at P<0.20Table 5. Multiple logistic regression results determining factors associated with survival time after surgical intervention of thymic epithelial tumours in catsLogistic regression SurvivalOR 95% CI P valueCystic appearance 3.02 0.58 to 15.63 0.187Tumour diameter 1.10 0.91 to 1.35 0.305Pleural effusion 0.52 0.74 to 3.67 0.512Masaoka- Koga stage 5.67 1.29 to 24.91 0.021Histological diagnosis (thymoma versus carcinoma)0.50 0.76 to 22.98 0.485Recurrence 3.43 0.74 to 15.83 0.113OR Odds ratio, CI Confidence interval.Variable highlighted in bold is statistically significant (significance set at P<0.05)Table 6. Simple logistic regression results determining factors associated with recurrence after surgical intervention of thymic epithelial tumours in catsLogistic regression Tumour recurrenceOR 95% CI P valueAge 0.83 0.61 to 1.14 0.261Purebred 0.02 0.00 to 23.81 0.302Gender 0.77 0.23 to 2.55 0.674Bodyweight 0.92 0.46 to 1.82 0.818Duration of clinical signs 1.00 0.93 to 1.08 0.885Respiratory signs 1.21 0.31 to 4.75 0.778Paraneoplastic syndrome 0.73 0.15 to 3.58 0.701Cystic appearance 1.34 0.35 to 5.17 0.667Tumour diameter 1.12 0.89 to 1.40 0.307Pleural effusion 1.71 0.48 to 6.08 0.402Masaoka- Koga stage 0.92 0.21 to 3.94 0.915Histological diagnosis (thymoma versus carcinoma)1.15 0.24 to 5.48 0.861Capsular invasion 0.62 0.14 to 2.66 0.525Mitotic count 0.98 0.83 to 1.16 0.870Complete excision 1.27 0.33 to 4.82 0.716OR Odds ratio, CI Confidence intervalReference category used in logistic regression. No variables had a P<0.20, therefore multi- variable analysis was not performed 17485827, 2024, 1, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jsap.13675 by Vetagro Sup Aef, Wiley Online Library on [19/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseT. A. Marks et al.Journal of Small Animal Practice • Vol 65 • January 2024 • © 2023 The Authors. Journal of Small Animal Practice published by John Wiley & Sons Ltd on behalf of British Small Animal Veterinary Association.54to radiotherapy could be evaluated in four of seven cats, two cats experienced a PR and two experienced a CR (Smith et al., 2001 ). The MST for all seven cats was 720 days (range, 485 to >1825; Smith et al., 2001 ). Similarly, Rohrer- Bley et al. (2018 ) described rapid tumour reductions in three cats with TET treated with neo -adjuvant radiotherapy (36 Gy delivered over 12 fractions) with survivals of 261, 362 and 680 days. These findings are encourag -ing and suggest further exploration would be worthwhile.While three cats with TET were treated with various chemo -therapy agents before or after surgery, the objective response to treatment and adverse events were not assessed in any of them. This, together with the small number of cases receiving chemo -therapy and the variable clinical circumstances under which it was given, precluded assessment of its efficacy. Further studies are needed to assess the role of chemotherapy when incomplete excision occurs in the absence of radiotherapy or in the neoad -juvant setting.In this study, the human Masaoka- Koga staging system was used, and it was associated with outcome for the cats undergoing TET excision: there was a significantly longer MST (1084 days) for cats with the lower disease stages (I to II). This staging system could therefore be applied to all cats undergoing surgical treat -ment of a TET and used as additional information to predict sur -vival time. Moreover, cats with more advanced stages may benefit from closer monitoring or adjunctive therapy.No differences were observed when comparing cats with completely or incompletely excised TET or when compar -ing the histological diagnosis between thymoma and thymic carcinoma. The importance of TET histological subtypes (thymoma versus thymic carcinoma) still needs to be clari -fied. Firstly, different subtype schemes have been used in both human and veterinary medicine, although more recently the World Health Organisation scheme (Marx et al., 2015 ) has been adopted. Secondly, there is marked interobserver varia -tion when assigning the histological subtypes in human TET (Dawson et al., 1994 , Detterbeck, 2006 , Verghese et al., 2008 ). Nevertheless, most human studies show that thymic carci -noma has the worst survival, but whether this has independent prognostic significance is unclear (Kondo et al., 2004 , Rea et al., 2004 , Rieker et al., 2008 , Weissferdt & Moran, 2015 , Knetki- Wróblewska et al., 2021 ). These histologic subtypes have not demonstrated prognostic significance in dogs (Bur -gess et al., 2016 ; Yale et al., 2021 ).As suggested in previous studies, the metastatic rate of TETs was low (3%) despite including six cats with thymic carcinomas (Patnaik et al., 2003 ; Garneau et al., 2014 ). Local recurrence was higher than previously reported and was identified in 11 cats (23%) and occurred late in the disease course, at a median TTP of 564 days ( Table 7). Five cats experienced recurrence despite histologically confirmed complete excision but no factors were found to be helpful for predicting recurrence. Assessment of mar -gin status in TETs may prove difficult due to tumour adherences to other structures and lack of tissue orientation; unless those relevant areas are inked, there is a risk that margins in some TETs could have been underestimated. The largest previous study on feline TET reported a 9% recurrence rate (Garneau et al., 2014 ). Based on these results, regular, active monitoring should be offered to owners of cats even if diagnosed with suspected com -pletely excised TETs. Further studies are warranted to identify factors influencing recurrence and to analyse the effect of adju -vant therapies on the rate of recurrence, especially in cats with microscopic or macroscopically incompletely excised tumours.This retrospective study has some limitations. This is the largest study of TETs in a purely feline population, but case numbers pre -vent us from being definitive about certain statistical findings. The multi- centre nature of the study and the long- time frame were asso -ciated with heterogeneous diagnostic and treatment approaches, and a significant number of patients that were lost to follow- up. Additionally, some cats were not fully staged or advanced imaging was not performed and the Masaoka- Koga staging system could not be applied. This staging system has also inherent limitations, as it relies on the presence of invasion on CT or intraoperatively, and those observations can sometimes be inaccurate. Restag -ing procedures were not standardised; this could have been due to variable owner compliance, the costs associated with imaging investigations or inconsistent recommendations made by differ -ent clinicians and could lead to tumour recurrence or metastasis being underestimated. A referral hospital bias may also be present: this includes case management by specialised surgeons, closer case monitoring and higher owner motivation to treat.Table 7. Summary of the available literature † describing treatment and outcomes of feline thymic epithelial tumoursNo. of catsTreatment Recurrence (no. of cats)Metastasis (no. of cats)Median survival time (days)Survival ratesGores et al. (1994 ) 12 Surgery 0 0 Survivals ranged from >180 to 1860– Smith et al. (2001 ) 7 Radiotherapy ±surgery ±chemotherapy3 – 720 – Patnaik et al. (2003 ) 14 Surgery ±chemotherapy ±radiotherapy1 3 – – Zitz et al. (2008 ) 9 Surgery 1 0 1825 89% at 1- year and 74% at 3- yearsGarneau et al. (2014 ) 32 Surgery ±chemotherapy 3 1 >1350 70%, 63%, 63% and 47% at 1- , 2- , 3- and 4- yearsPresent study 64 Surgery ±chemotherapy ±radiotherapy and palliative treatment11 2 897 86%, 70%, and 66% at 1- , 2- and 5- years†Studies included had a minimum of five cats 17485827, 2024, 1, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jsap.13675 by Vetagro Sup Aef, Wiley Online Library on [19/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseThymic epithelial tumours in catsJournal of Small Animal Practice • Vol 65 • January 2024 • © 2023 The Authors. Journal of Small Animal Practice published by John Wiley & Sons Ltd on behalf of British Small Animal Veterinary Association.55 This study suggests that surgical excision of TET in cats is associated with a favourable long- term prognosis; however, late local recurrence is a risk. Cats with advanced Masaoka- Koga stage may benefit from closer active monitoring after surgery or adjuvant therapy. The role of radiotherapy and chemotherapy in cats warrants further study. A better understanding of tumour biology and trials of adjunctive therapy is also needed and may allow a more individualised treatment approach.Conflict of interestNone of the authors of this article has a financial or personal relationship with other people or organisations that could inap -propriately influence or bias the content of the paper.Author contributionsThomas A. Marks: Conceptualization (equal); data curation (equal); validation (equal); writing – original draft (equal). Matteo Rossanese: Conceptualization (equal); data curation (equal); formal analysis (equal); methodology (equal); supervi -sion (equal); validation (equal); writing – original draft (equal). Andrew D. Yale: Conceptualization (equal); data curation (equal); methodology (equal). Sarah Stewart: Conceptualization (equal); supervision (equal); writing – review and editing (equal). Katherine Smallwood: Conceptualization (equal); data cura -tion (equal); writing – review and editing (equal). Konstantinos Rigas: Conceptualization (equal); data curation (equal); writing – review and editing (equal). Alexandra Guillén: Conceptualiza -tion (equal); data curation (equal); formal analysis (equal); meth -odology (equal); supervision (equal); validation (equal); writing – original draft (equal).Data availability statementThe data that support the findings of this study are available from the corresponding author upon reasonable request.

Answer 28

To the authors’ knowledge, this was the first study to investigate for risk factors and incidence of urinary tract rupture in UO cats. This study found that the prevalence of iatrogenic urinary tract rup -ture resulting from urinary catheterization is low at 0.92%. This information can be useful to prepare cat owners for the actual risk of this complication and additionally can be used as a benchmark to moni -tor adverse events. Additionally, we identified that a more difficult urinary catheter placement and a previous history of UO were significantly associated with urinary rupture.The urethra was the most common location of the rupture identified in our study. This was similar to a previous retrospective study9 that noted that out of 7 cats that developed a uroperitoneum following urinary catheter placement, 71% had rupture of the urethra and the remainder (29%) had rupture of the bladder. The urethra is likely the most common site of injury, as it receives direct trauma from the cath -eter during placement and is also the site of obstruc -tion and, therefore, greatest resistance. Two cats in our study had a confirmed or suspected bladder tear. This condition could have developed as a result of urohydropropulsion when saline is flushed to facili -tate urinary catheter placement. Excessive distension and elevated intraluminal pressure within the blad -der caused by instillation of fluid leading to bladder rupture has been previously described in people, al -though it is an extremely rare complication.14Cats with urinary tract rupture had a significantly higher difficulty in catheterization score compared to UO-C cats. An association between difficult catheter -ization and urinary tear in the feline population has not been previously described in existing veterinary literature. However, it has been reported as a known risk in difficult urinary catheter placement in human males.15,16 When faced with a difficult urethral cathe -terization in people, a variety of techniques including urethral dilation, cystoscopy-guided placement, and passage of an initial guidewire are typically imple -mented, and continued attempts at blind placement are strongly discouraged given the risks for iatrogen -ic damage.17 This study suggests that a similar rela -tionship between difficult catheterization and lower urinary tear also exists in the feline population.There is not extensive literature exploring the risks associated with specific catheter types (rigid vs flexible) in either human or veterinary patients. Dur -ing the study period, an open-ended stylet urinary catheter (3.5-F 25-cm Tomcat catheter with stylet; MILA International Inc) was the standard catheter in use in our hospital for initial treatment of UO. How -ever, in cases of difficult catheter passage (scores of > 3) multiple types of catheters used may have included open-ended Tomcat catheters, red rubber catheters, or even stainless-steel olive tip cannulas, some of which are more rigid and could have resulted in additional trauma and contributed to urinary tract rupture. The experience of the individual performing the catheterization, exact number of catheterization attempts, and exact types of catheters used could not be assessed as individual risk factors for urinary rupture in our study because they were unreliably recorded in the medical record. These individual fac -tors warrant additional prospective investigation.Consistent with our hypothesis, cases in the UO-R group were significantly more likely to have had a his -tory of previous UO treated with urinary catheteriza -tion. Previous UO may lead to sequelae such as ure -thral stricture, thinning of the tissue, or fibrosis of the urethral tissue predisposing the cat to urethral injury and rupture. In people, it is known that challenging catheterization and urethral trauma often leads to the development of chronic urethral strictures, presenting a challenge for future catheterizations.18 Although di -agnosing stricture formation in cats is challenging, a similar relationship could exist on the basis of these study results. Additionally, recent urethral catheter -ization may lead to additional inflammation second -ary to the iatrogenic trauma, which may lead to in -creased tissue friability and inflammation.Contrary to our hypothesis, the severity of dis -ease as reflected by creatinine, pH, and ionized cal -cium was not significantly different between groups. Although a previous necropsy study identified more severe urinary tract lesions such as mucosal/submu -cosal edema and necrosis in cats that were more se -verely ill, this did not appear to be a risk factor for urethral or bladder rupture in our study .12 Of the ad -mission blood work parameters, only Hct was signifi -cantly different between the UO-R cats and the con -trol group, with the UO-R cats having a significantly higher Hct. The clinical significance of this finding is unknown, as the Hct in both groups was still within the normal reference range for cats. There is a pos -sibility that the higher median Hct in the UO-R cats could reflect hemoconcentration secondary to dehydra -tion. Dehydration has been shown to affect the structure of collagen, which is normally a highly water-bound Unauthenticated | Downloaded 01/27/24 05:10 PM UTC JAVMA | FEBRUARY 2024 | VOL 262 | NO. 2 191protein that has been shown to be the main determi -nant of urethral tissue integrity at high luminal pres -sures.19 Dehydration leads to shrinkage of collagen fibers and increased stiffness, which may lead to changes in the tissue’s performance under high stress conditions, contributing to tissue rupture.20,21The duration of hospitalization was significantly longer and survival to discharge was significantly lower in the UO-R group than the UO-C group. This includes both cats that were euthanized as well as the single cat that had a cardiopulmonary arrest in hospital. Cats may have been more likely to have been euthanized due to perceived poor prognosis and/or owner financial limitations. Treatment of uri -nary rupture leads to increased hospitalization time, which may carry a substantial cost to owners, result -ing in decisions to euthanize. The increased death in the UO-R cats may also be related to potential com -plications of the urinary tract rupture such as uro -peritoneum, urosepsis, and persistent azotemia.22 Additionally, more intensive treatment interventions including surgical repair carries additional risks as -sociated with general anesthesia and risks such as in -fection and persistent cystitis associated with these invasive procedures.23,24 The retrospective nature of the study and the confounding factor of euthanasia makes prognosis and true mortality rate challenging to assess.There were several limitations of this study. This was a retrospective study with a small sample size. Given the small sample size, the study population may not accurately reflect the true population and some cases were not able to be included in the study given the lack of conclusive imaging studies and/or incomplete records. In addition, as mentioned above, the experience level of the person perform -ing the urinary catheterization and catheter type used were not able to be assessed as risk factors and warrant additional investigation in larger multicenter prospective studies.Overall, urethral and bladder tears are an un -common sequela of UO in cats presenting to the emergency room. A previous history of UO and dif -ficult catheter passage should alert clinicians to an increased incidence of this complication. Cats with urethral and bladder tears have a significantly longer period of hospitalization and decreased survival to discharge than their counterparts that do not suffer this complication.AcknowledgmentsNone reported.DisclosuresThe authors have nothing to disclose. No AI-assisted technologies were used in the generation of this manuscript.FundingThe authors have nothing to disclose.

Answer 29

This study demonstrates the feasibility of a novel technique for the treatment of atrophic/oligotrophic non-unions of radius/ulna and tibia/fibula in dogs and cats. Surgical treatment in this cohort was successful in 94.7% of patients; this is comparable to that of previous studies and lies between the previously described 43% and 100% (Marshall et al., 2022 ; Massie et al., 2017 ; Munakata Table 2. Bone segments alignment and shortening dataCase Bone segment involvedEstimated percentage bone loss after debridement (%)Bone shortening at the time of bone healing (%)Operated limb FPA (°)Controlateral limb FPA (°)Operated limb SPA (°)Controlateral limb SPA (°)1A Tibia 39.5 9.1 4.2 5.3 20.3 18.82A Radius 27.7 16.7 6.0 6.5 4.1 6.73A Radius 22.0 1.5 11.2 8.8 10.9 10.04A Radius 25.0 6.3 1.6 2.3 18.0 20.15A Radius 21.4 4.3 4.9 3.7 9.4 8.86A Tibia 21.2 5.0 9.0 8.5 18.2 21.07A Radius 25.0 12.5 23.0 12.9 7.7 9.18A Radius 22.7 6.4 3.5 4.0 6.6 8.310A Tibia 22.1 5.0 10.7 8.9 12.3 15.011A Radius 24.3 4.4 2.5 3.2 9.1 9.412A Radius 22.5 2.8 5.7 6.4 15.2 17.113A Tibia 21.2 4.3 8.2 8.5 20.3 19.41B Radius 33.8 10.0 6.4 3.8 3.2 3.52B Tibia 23.6 17.3 15.1 13.2 15.7 18.63B Tibia 35.3 24.7 11.7 11.9 22.1 23.04B Tibia 22.7 2.8 8.7 8.4 22.3 24.65B Radius 27.2 4.6 2.0 0.0 3.2 3.66B Radius 22.6 7.9 0.0 0.0 4.0 3.5FPA Frontal plane alignment, SPA Sagittal plane alignment 17485827, 2024, 2, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jsap.13681 by Vetagro Sup Aef, Wiley Online Library on [04/02/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseCESF and bone graft treating non-unionJournal of Small Animal Practice • Vol 65 • February 2024 • © 2023 British Small Animal Veterinary Association. 129 et al., 2018 ). One study reported a 100% success rate using fro -zen cortical bone allografts in 15 dogs with radius and ulna non-union (Munakata et al., 2018 ). In that study, it was necessary to perform a pancarpal arthrodesis in nine out of 15 patients (60%), due to the fact that the size of the bone fragments was too small for plate and screw placement. In the present study, it was possible to place implants in bone segments of a few millime -tres in size and this can be considered an advantage over internal fixation. Massie et al. (2017 ) reported a high success rate using compression resistant matrix infused with recombinant human bone morphogenetic protein (rhBMP-2) in the treatment of non-unions in dogs. However, these studies reported the use of materials, such as bone grafts from bone banks and rhBMP , the availability of which is sometimes limited in veterinary practice and associated with significant cost.Autologous bone graft has osteogenic, osteoconductive and osteoinductive properties, and it is safe and cost-effective (Azi et al., 2016 ). Limitations of autologous bone graft are the lim -ited volume of material that can be obtained, the morbidity of the donor site and the prolonged anaesthesia time. Therefore, efforts have been made to explore alternatives, such as allograft, ceramics, platelet-rich plasma (PRP) and rhBPMs (Ragetly & Griffon, 2011 ). Despite this, no material has all the properties of autologous graft; bone allograft is variable in its osteoin -ductive and osteoconductive properties and has no osteogenic potential, ceramics are mainly osteoconductive, while rhBPMs are mainly osteoinductive. Several reports on the application of PRP in combination with autograft have given conflicting results (Malhotra et al., 2013 ; Zhang et al., 2021 ). In several studies, it has been confirmed that rhBMPs stimulate bone healing, but at the same time the potential for their side effects has emerged. Side effects of rhBMPs include ectopic bone formation, osteoclast-mediated bone resorption and compli -cations associated with inflammation (Li et al., 2022 ). Further -more, some researches have revealed the potential of processed bone allografts to transmit pathogens, such as feline retrovi -rus, suggesting that there is a risk of disease transmission when allografts are used (Nemzek et al., 1996 ; Wenz et al., 2001 ). The use of an autologous bone graft overcomes the disadvan -tages mentioned above and the technique described in this work is attainable in most veterinary hospitals.In every patient, a debridement was needed to expose viable bone, leading to the formation of a bone gap, and the decision to use a ACBG was related to the fact that this gap would be difficult to fill with a cancellous graft alone. Thus, the use of an autologous material that included both cancellous and corti -cal bone allowed the bridging of defects that would otherwise have required the combined use of other materials, increasing the costs and potential risks. An alternative to bridging the bone defects would be the standard non-union treatment with rigid fixation and autologous cancellous graft, but this would have probably required an additional debridement of the bone seg -ments to ensure sufficient contact between the fracture edges. In each patient, in fact, aggressive debridement was performed, but was stopped as soon as viable bone was identified. In many cases, this led to debridement being stopped before perfect matching of the proximal and distal edges was achieved, due to the thinning of the bone ends related to non-union. This was possible because the CESF was used in bridge fashion, filling the fracture gaps with the ACBG.One patient was re-operated by standard treatment, placing the bone ends in full contact after further debridement, stabi -lising the site with plate and screws, and applying a cancellous autograft. The non-union healed but there was a significant shortening of the segment and the dog developed a lameness and a slight palmigrade stance. The cause of the palmigrade stance was not clear, but the authors believe it may be related to the shortening of the radius/ulna, which prevented proper tension of the flexor carpi ulnaris muscle on the accessory carpal bone in the stance phase, as hypothesised in a recent report (Vezzoni et al., 2021 ). Considering the limited data on the exact percent -age of bone shortening tolerated by small animals, especially for forelimb, ACBG may be useful to fill gaps and spare bone length, providing at the same time osteogenesis, osteoinduction and osteoconduction.Studies on ACBG in dogs and cats are lacking and often limited to single case reports (Boudrieau et al., 1994 ; Choi & Yoon, 2022 ; Chung et al., 2021 ). These studies report the use of different sites for autograft, such as rib and coccyx. The choice to use the wing of the ilium was dictated by the ease of surgery, and the fact that the risks associated with iatrogenic damage are minimal in this area (Kraus & Martinez, 2018 ). Conversely, the use of coccygeal vertebrae requires a caudectomy, and the surgi -cal approach to harvest a rib graft can cause incidental incision of the pleura and subsequent pneumothorax. In the present work, the collection procedure was fast, and considered simple. There was no difference in the size of the grafts obtained using the two collecting techniques, and graft integration was achieved in the majority of patients regardless of type of harvesting. An advan -tage of these techniques is that they provide a large and effective graft using only one donor site. This limits the risks of complica -tions related to the multiple donor site approach and reduces the surgical time.Considering that the use of a cortical graft can cause the for -mation of a sequestrum, all patients with signs of infection were excluded from the procedure. Furthermore, previous studies have shown that bone healing can be achieved in infected non-unions treated with cortical allograft provided that debridement of nonviable tissue, surgical site lavage, appropriate antibiotic therapy and proper fixation are ensured (Munakata et al., 2018 ; Sinibaldi, 1989 ). In this series, patients did not develop postop -erative infections, the grafts were incorporated into the bone cal -lus, and no sequestra formation was seen. Despite these patients having no clinical signs of infection, it was decided to administer antibiotics in the postoperative period, and to continue admin -istration even though negative cultures were present. This choice was related to the fact that, in some cases, non-unions may be considered sterile based on traditional bacterial identification techniques, but actually be infected due to the presence of bio -film (Palmer et al., 2014 ).The CESF was chosen because its mechanical properties excel -lently counteract rotational and bending forces at the fracture site 17485827, 2024, 2, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jsap.13681 by Vetagro Sup Aef, Wiley Online Library on [04/02/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseP . Camilletti and M. d'AmatoJournal of Small Animal Practice • Vol 65 • February 2024 • © 2023 British Small Animal Veterinary Association. 130and axial micromovements permitted by this implant stimulate bone calcification (Ferretti, 1991 ). The implant was well tolerated and the patients started using the operated limb in the first post -operative week, during which the administration of meloxicam was sufficient for pain control. In addition to its effects, meloxi -cam was chosen for its palatability and the fact that it can be used for long periods of time. This would have made it possible to continue NSAID therapy for longer, if it had been considered necessary at the time of the first postoperative examination. This modified application of the CESF is an efficient solution for cats and small breed dogs, especially in the cases with a small distal bone segment; the healing period reported in this study was faster or similar to that shown in other studies and this method more quickly restored an acceptable bone length and with a complica -tion rate similar to that reported with other techniques (Blaeser et al., 2003 ; Massie et al., 2017 ; McCartney, 2008 ; Munakata et al., 2018 ). One dog developed an angular deviation in the peri -operative period, in the absence of implant rupture. The authors hypothesise that this deviation could be related to the loosening of the bone-implant interface. The K-wires are in fact thin com -pared to other implants, so high stresses generated at the wire-bone interfaces can exceed the strength of the bone, leading to the bone yielding.This work has several limitations related to its clinical nature. These limitations are the consequence of the retrospective design, heterogeneity of the sample population and the small number of cases that were included. The treatment was not randomised and therefore preoperative and intraoperative decision-making is a source of bias in the results of this study. Torsional malalign -ment was physically and subjectively judged by the authors with -out the use of a goniometer, and an objective assessment was not performed. A radiographic calibration marker was not used, which is an important limitation in the calculation of debride -ment-related bone loss, due to the magnification error. The use of clinical metrology instruments was useful in assessing pain and function, eliminating the stress response factor that patients may exhibit during examinations in the veterinary hospital. However, due to the nature of the study and the type of injuries treated, it was not possible to extrapolate data to objectively compare the patient’s condition in the pre- and post-treatment period. A prospective longitudinal study that includes more advanced diagnostic tools, such as CT scan to assess the alignment of bone segments and objective postoperative force-plate analysis to assess improvement of limb function would be ideal to better evaluate the possible outcomes and complications of this technique.Based on the review of available literature, this is the first clini -cal study that reported the association of autologous iliac cortico -cancellous bone graft with CESF for the treatment of non-unions in small animals. In conclusion, we successfully treated 18 atro -phic/oligotrophic non-unions using both traditional and en bloc debridement, providing a safe and effective autologous bone graft to assure osteogenetic and osteoinductive functions and acting at the same time as a scaffold to bridge long bones defects.AcknowledgementsThis article was supported by IVC Evidensia.Conflict of interestNone of the authors of this article has a financial or personal relationship with other people or organisations that could inap -propriately influence or bias the content of the paper.Author contributionsPaolo Camilletti: Conceptualization (equal); data curation (lead); formal analysis (equal); investigation (lead); methodology (lead); validation (supporting); writing – original draft (lead); writing – review and editing (equal). Michele d’Amato: Concep -tualization (equal); data curation (supporting); formal analysis (equal); investigation (supporting); methodology (supporting); validation (lead); writing – original draft (supporting); writing – review and editing (equal).

Answer 30

For dogs in the present study, wide surgical exci -sion of locally aggressive tumors of the distal extremi -ties, managed with repeated applications of an acel -lular FSG, resulted in complete wound healing. The wound bed remained consistently healthy throughout the study. There were no apparent direct complications related to the use of the FSG, but epithelialized skin was thin and prone to injury. No local recurrence was noted for any cases within the follow-up time period.The acellular FSG product used in this study has been FDA approved for use in humans for partial- and full-thickness wounds secondary to trauma or surgery, draining wounds, soft tissue reinforcement, and various types of ulcers (eg, pressure, venous, diabetes, etc).28,39 The 3-D microporous structure of the FSG enables the harmonious colonization of autologous cells, such as fi -broblasts, to infiltrate the area and promote angiogen -esis.40 The xenograft, which transitions into living tissue, slowly becomes incorporated in the wound bed as the new granulation tissue develops. FSGs were applied to the wound between 5 and 18 days, suggesting com -plete integration within this time frame. This is similar to the length of time documented for FSG wound integra -tion in human medicine, between 7 and 10 days.36A noticeable reduction in wound size was first ap -preciated within the first 2 to 4 weeks of healing. This is comparable with the time frame of a study31 that com -pared the rate of wound closures using FSG on deep par -tial-thickness burn wounds in pigs. Wound contraction begins once there is a significant amount of myofibro -blasts within the ECM. As healing progresses, the number of fibroblasts typically decrease in the wound, correlating to a decrease in contractility.41 When wound contraction stops prior to full wound coverage, the remaining granu -lation bed must be covered solely by the processes of re-epithelialization. FSGs have been shown to speed the rate of re-epithelialization without an increase in contraction, when compared to wounds covered with a fetal bovine ADM or wound healing by second intention alone.31 The authors suspect that by continuously reapplying FSGs and thus supplying beneficial qualities to the granulation bed, the wound is able to maintain an accelerated rate of epithelialization. The rate of epithelialization in a large dog bite wound treated with tilapia fish skin graft was calculated to be 1.76 mm/d, accelerated compared to 1 mm/d (normal rate of re-epithelialization).37 This theory may be able to explain how the wounds in this study con -tinued to decrease in size by a greater degree between the sixth to eighth week of healing, compared to earlier time points in the study.Complete epithelialization occurred within 7 to 9 weeks for the 3 uncomplicated wounds and 12 to 15 weeks for the remaining 2 complicated wounds that sustained self-trauma. These findings demonstrate a Figure 2 —Progression of second-intention wound heal -ing in 5 dogs following wide tumor excision managed with repeated applications of FSG.ComplicationsThere were no adverse events directly related to the use of FSGs. Bandage-related complications were mild and included swelling of the digits or interdigi -tal dermatitis, intermittent lameness, bandage slip -page, and premature removal of the bandage. Dog 1 was placed on a 14-day course of oral amoxicillin–clavulanic acid (Clavamox), 15 mg/kg, secondary to a suspected surgical site infection at the superficial cervical lymph node extirpation site (erythema, heat, and swelling noted). Due to lack of owner compli -ance, dog 2 was presented several times through the emergency service, outside of scheduled bandage changes, due to chewing off the bandage and self-trauma to the wound bed. As a result, additional primary dressings were used, including honey algi -nate and a bioresorbable polymer matrix (Microlyte; Imbed Bio). Dog 2 was also placed on a 14-day course of oral amoxicillin–clavulanic acid, 15 mg/kg, follow -ing self-trauma to the wound bed; however, no culture was obtained. Dog 4 self-traumatized the wound bed following almost complete epithelialization, resulting in prolonged wound care of an additional 2 weeks. Dog 5 reportedly retraumatized the new skin several weeks after the conclusion of the study that was man -aged by the owner and eventually healed. During this second period of bandaging, the dog was reported to have ingested bandage material, requiring endoscopy Unauthenticated | Downloaded 10/08/23 06:32 AM UTC1552 JAVMA | OCTOBER 2023 | VOL 261 | NO. 10similar to slightly shorter time to healing as a retrospec -tive study13 of 31 dogs comparing the rates of second- intention healing after wide resections of STS on distal limbs, in which 77% of wounds healed by 12 weeks. The final length of time to heal for the remaining 23% was not disclosed. The prolonged healing exhibited from dogs 2 and 4 was a result of wound complications sec -ondary to self-trauma. The wounds in this study ranged from 17.6 to 58.7 cm2. It is generally expected that larger wounds typically take a longer time to heal com -pletely.42,43 However, despite dog 5 having the largest wound following STS scar revision and mass removal, complete epithelialization occurred within 7 weeks. The previously mentioned study evaluating second-in -tention healing for STSs reported wounds that ranged in size from 18.84 to 113.10 cm2 and found that there was no significant relationship between surface area of wounds and their time to healing.13For evaluation of the health of the granulation bed, percentage of tissue color was measured. All wounds maintained a healthy bed of granulation tissue (red) throughout the course of treatment. Objective tissue col -or measurements can help guide clinical decision-mak -ing. While not appreciated during this study, devitalized or necrotic tissue could be debrided to expose a layer of vascular tissue, and repeated debridements followed by applications of FSG to the wound would likely promote greater 3-D cell ingrowth and tissue regeneration.14,35Postoperative complication rates following various reconstructive techniques have been reported to be be -tween 50% and 70% and include skin graft or flap failure, surgical site dehiscence and infections, seroma forma -tions, and bandage-induced complications.7,8,11,42,44 Ad-ditionally, the need for secondary surgical procedures following complications with healing secondary to both reconstructive surgery and wound beds unable to heal by second intention alone has been reported.8,13,44 None of the dogs in the current study required any additional surgical procedures to facilitate complete healing by second intention with the use of the FSG.Second-intention healing has been linked to a short-term complication rate of 22.6% due to bandage complications and surgical site infection.13,19 Bandage complications reported include mild erythema, swelling, and pain to more severe consequences such as ischemic injury.18 The bandage-related injuries experienced in this study were mild and similar to what has been previously reported.8,11,42 The most common injuries seen in this study were swollen digits, which resolved with applica -tion of a new soft padded bandage. Prolonged wound healing exhibited in 2 dogs was a result of self-trauma to the wound. These findings emphasized the need for proper bandage placement and client education in ban -dage care. While leaving a wound to heal by second -ary intention risks the development of resistant infec -tion,13,19 none of the cases in the current study showed any evidence of developing an infection. The use of FSG in large wounds has proven to accelerate epitheliali -zation and therefore can limit exposure for potential infection and associated morbidity to occur.31 The omega-3 fatty acids within the FSGs have antibac -terial properties against multiresistant bacteria and play a key role in the graft’s ability to act as a physical bacterial barrier.36 It has been demonstrated that FSG can withstand bacteria invasion for up to 72 hours.36 While 2 dogs received antibiotics during the course of the study, dog 1 received antibiotics for a suspected un -related infection distant to the surgery site and dog 2 received antibiotics prophylactically from an emergency service without a culture obtained from the wound bed or evidence of an active infection.In 1 study,13 long-term complications from second-intention healing following wide STS excision of the dis -tal limb was seen in 25.8% of dogs. The most common long-term complication in that study was intermittent disruption of the epidermis due to trauma. Similarly in this study, several dogs traumatized the thin layer of epithelial tissue over the wound bed. Healing by second intention relies on maturation and reorganization of the thin layer of epithelial cells to regain, at most, 80% of nor -mal tissue strength, and this process can take 30 days to 1 year.41 The other complication experienced in that study was decreased range of motion over a joint sec -ondary to wound contracture. Because the inelastic scar tissue formed from second-intention healing inhibits joint extension, significant wounds over a joint’s flexor surface may result in contracture and then subsequent pain and lameness.13 Although none of the dogs in this study had a wound directly over a joint, applying FSG may be protective against contracture complications ex -perienced with second-intention healing. A review in hu -man literature references several studies that prove ADM applied in wounds over a joint, or wounds with exposed tendon, result in minimal scar contracture and normal range of motion.29 Second-intention healing faces the challenge of lack of skin and the combative forces be -tween tension on the wound edges and the contraction forces of myofibroblasts, which often result in incom -plete wound healing.41 None of the dogs treated with FSG experienced incomplete wound healing.Wide surgical excisions are performed with the intention of obtaining histologically clean margins to prevent tumor recurrence. Despite taking 2-cm lateral and 1 fascial plane–deep margins, complete surgi -cal excision was only accomplished in 2 of the 5 dogs within this study. There has been no evidence of local tumor recurrence noted on long-term follow-up. Other studies, utilizing reconstructive techniques for closure of wide tumor excision on the limbs of animals, have achieved clean margins in 66% and 58% of cases.7,8 Fac-tors that can increase the risk for incomplete excision of MCT and STS include decreased body weight and in -creased tumor size.2 Tumors located on the distal limb compared to those on the head or neck have also been shown to influence the ability of obtaining clean sur -gical margins of STS.2 Several studies have found that incomplete excision of MCT is not related to location, which is contradicted by others that have found MCTs in the hind limbs to be positively correlated with inade -quate margins.2,45,46 The lack of tumor recurrence could be due to the low histologic grade of the tumors or dis -crepancies that occur from sample processing result -ing in inaccurate histologic margin measurements.47,48 The beneficial characteristics of FSGs, such as anti- inflammatory properties, have been studied fairly well in human medicine and are linked to the omega-3 Unauthenticated | Downloaded 10/08/23 06:32 AM UTC JAVMA | OCTOBER 2023 | VOL 261 | NO. 10 1553polyunsaturated fatty acids.28,31,36 Oral supplemen -tation of omega-3 polyunsaturated fatty acids has been used in both human and veterinary medicine as an antineoplasia nutraceutical; however, most of the beneficial inhibitory properties are linked to the immu -nomodulatory and anti-inflammatory effects.49–51 Ad-ditional research is required to determine whether the application of FSGs has any antineoplastic properties.The main limitations of the present case series were the small sample size and lack of control group, making it challenging to analyze the effects of wound size, number of FSG applications, individual variances in healing, and time between FSG applications on wound healing. Dog 1 in the study had the first FSG applied 1 week after initial mass removal and subsequent failure of a skin graft. This wound bed may have received different initial stimulation in comparison to the naive wound beds. Additionally, an artificial intelligence software (InSight; eKare Inc) was used to document wound healing progression of each case and tissue health. Occasionally, wounds were noted to increase in size from prior measurements. This could be secondary to the quality of the image, lighting, positioning of the limb, and positioning of the reference marker. For the most ac -curate results, the wound needs to be captured straight on and a reference marker placed in the same plane as the wound to calibrate the image. To improve consistency, on subsequent photography of the wounds, the previous assessment image is ghosted on the screen to assist the user in capturing the wound from the same perspective. This minimizes positioning error. The version of the device used in this study could not yet accommodate the curved or partially circumferential aspect to limb wounds, mak -ing accurate measurement challenging. However, the cur -rent updated version can calculate accurate surface area of circumferential wounds. The software also had limita -tions on evaluation of tissue health. Areas of light refrac -tion were often designated as black and variability in the canine skin margin would yield colors of yellow, incorrectly categorizing these regions as necrotic and devitalized tis -sue, respectively. Images were always evaluated for qual -ity control and manually adjusted as needed to correct for these discrepancies. Despite these minor limitations, the software was easy to use and documented progression of canine wound healing quite effectively. While sedation was used to facilitate reapplication of FSGs, it was typically unnecessary in the later stages of wound healing. Further -more, sedation is commonly incorporated into wound care to improve patient comfort and minimize restraint required during dressing changes.The use of acellular FSGs in dogs for the manage -ment of second-intention wound healing following wide surgical excision for locally invasive tumors is well tolerated and resulted in complete wound healing in all cases. The application of acellular FSGs was not attributable to any adverse effects. Acellular FSG is an affordable and shelf-stable product that does not require specialty training and can be easily utilized by both general and specialty practices in wound ther -apy management. Wide surgical excision of locally aggressive tumors closed via second-intention heal -ing promoted with FSG applications may have some advantages over second-intention healing alone. A larger study that compares both groups is warranted.AcknowledgmentsThis study was supported in part by the University of Florida Department of Small Animal Clinical Sciences.The authors thank Kerecis for donating the fish skin used in this study and eKare, InSight for their technical support.

Answer 31

This in silico study was designed to quantify the impactof TLA shift on postoperative versus planned TPA toimprove the accuracy of surgical planning. We observedthat all techniques induced a TLA shift that influencedthe expected postoperative TPA. Pearson's correlationcoefficients between wedge angle and TPA correctionand between wedge angle and TLA shift would suggest astrongly linear relationship between these variables in allstudied CCWO techniques. Therefore, we concluded thattibial confirmation did not have an effect on TPA correc-tion across our data set and accept our hypothesis.The generated equations represent a dynamic ad-justment to TLA shift, observed with increasing wedgeangles, and may be applicable across different tibial con-formations. As a practical example, if a 30/C14TPA was tobe reduced to 5/C14, using the mCCWO as per Oxley et al.,16then the corrected wedge angle would be:Wedge angle ¼30/C14/C05/C14ðÞ /C2 1:19/C00:87Wedge angle ¼28:9/C14Providing the CCWO are planned as described in thisstudy, using the generated equations, may improve theFIGURE 4 Box plots showing tibiallong axis shift (/C14)i n1 0/C14increments upto 70/C14, using the cranial closing wedgeostectomy techniques as described bySlocum & Devine.,1Oxley et al.,16Frederick & Cross.,17and Christ et al.18Box plot explanation as for Figure 3.FIGURE 5 Box plots showingmechanical tibial length change (%) in10/C14increments up to 70/C14, using thecranial closing wedge ostectomytechniques as described by Slocum &Devine.,1Oxley et al.,16Frederick &Cross.,17and Christ et al.18Box plotexplanation as for Figure 3.MOREIRA ET AL . 149 1532950x, 2024, 1, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14033 by Cochrane France, Wiley Online Library on [05/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensesurgical planning accuracy of the studied CCWO, whencompared to the previously reported range of staticwedge angle corrections between TPA /C05/C14and+7.5/C14.10,12,14 –19,21Outcome inconsistency betweenplanned CCWO and the achieved results may still beobserved though the application of these equations, espe-cially at steeper TPAs, given the more pronounced disper-sion of TPA corrections observed at higher wedge angles.Tibial long axis shift varied in somewhat similar mag-nitude between all techniques up to 40/C14. However, pastthis threshold, it became more pronounced in themCCWO techniques. This finding appeared to be theconsequence of a greater caudal translation of the proxi-mal segment, to achieve cranial cortical alignment, in thetraditional CCWO, effectively decreasing the TLA shift.In contrast, past 40/C14TLA shift was less pronounced uponaxial rotation of the proximal segment, prior to cranialcortical alignment in all studied mCCWO techniques.These techniques, however, employed either minimal17,18or no16caudal translation of the proximal segment toachieve alignment of the cranial cortices. As such, accu-rate reduction of the cranial cortices was most importantin the Slocum and Devine1CCWO to achieve accuratetarget TPA in this in silico study.Amongst the mCCWO, greater TLA shift was consis-tently observed in the mCCWO as per Frederick andCross.17The more cranio-distal pivot point, in themCCWO as per Frederick and Cross17and Christ et al.18resulted in greater axial rotations, prior to cranial corticalalignment, when compared to the Oxley mCCWO.16However, the smaller wedge base sizes in the Frederickand Cross17mCCWO resulted lesser sagittal cortical dis-parity and, thus, in lesser caudal translations of the proxi-mal segment to achieve cranial cortical alignment.Tibial shortening, while repeatedly considered aconsequence of the CCWO technique, is not commonlyreported in current literature. To date, only Christet al.,18Campbell et al.15and Wallace et al.21measuredpre- and postoperative tibial length, which highlighteda more pronounced tibial shortening with the tradi-tional CCWO. Within these reports, though, theirresults were not presented normalized and thus a directcomparison between techniques was not entirely possi-ble given the wide range of described tibiallengths.15,18,21Similar findings were observed in thisstudy, with the new wedge designs being more effectivein limiting tibial shortening when compared to the orig-inal CCWO.1This difference again became more pro-nounced past 40/C14wedges with Slocum and Devine's1CCWO registering up to 40.9% reduction in %mTL. Incomparison, %mTL reduction reached a maximum of12.0%, 7.5% and 9.5% in Oxley et al.,16Frederick andCross17and Christ et al.18respective mCCWO. TheTABLE 1 Mean ± standard deviation of the tibial long axis shift ( º) upon axial rotation prior to cranial cortical alignment; cranial-caudal translation of the tibial proximal segment (mm)to achieve cranial cortical alignment; and wedge base size (%) normalized as a percentage of the original mechanical tibial length.WedgeangleTLA shift without cranial corticalalignmentCranio-caudal translation of the proximalsegment (mm) Wedge base size (%mTL)Slocum &Devine1Frederick &Cross17Christet al.18Slocum &Devine1Frederick &Cross17Christet al.18Slocum &Devine1Oxleyet al.16Frederick &Cross17Christet al.1810/C141.1 ± 0.4 1.8 ± 0.2 1.9 ± 0.3 0.4 ± 0.3 1.7 ± 0.7 2.2 ± 0.8 3.9 ± 3.1 3.2 ± 0.4 2.6 ± 0.6 3.2 ± 0.420/C143.0 ± 0.5 3.7 ± 0.4 3.8 ± 0.5 1.3 ± 0.5 2.6 ± 1.1 3.2 ± 1.3 6.7 ± 3.2 6.7 ± 1.6 4.7 ± 0.7 5.4 ± 1.030/C145.4 ± 0.7 5.5 ± 0.7 5.6 ± 0.8 3.3 ± 1.1 3.0 ± 1.3 3.6 ± 1.4 9.8 ± 3.3 9.5 ± 1.4 6.6 ± 0.9 7.5 ± 1.040/C148.5 ± 1.2 7.4 ± 0.9 7.4 ± 1.0 7.0 ± 2.2 3.1 ± 1.6 3.8 ± 1.6 13.0 ± 3.5 12.3 ± 1.3 8.6 ± 1.1 9.6 ± 1.050/C1412.7 ± 1.9 9.2 ± 1.1 9.1 ± 1.3 12.9 ± 4.4 3.0 ± 1.8 3.7 ± 1.7 17.7 ± 3.9 15.1 ± 1.4 10.9 ± 1.2 11.8 ± 1.060/C1418.9 ± 3.6 10.9 ± 1.4 10.7 ± 1.6 21.8 ± 7.6 2.6 ± 1.9 3.4 ± 1.7 24.4 ± 5.1 18.1 ± 1.6 13.0 ± 1.3 14.5 ± 1.270/C1430.9 ± 6.3 12.4 ± 1.7 12.2 ± 2.1 37.1 ± 12.6 1.9 ± 1.7 2.9 ± 1.4 36.1 ± 6.8 21.7 ± 2.0 15.7 ± 1.6 17.2 ± 1.7Note: Tibial long axis shift without cranial cortical alignment and cranio-caudal translation of the proximal segment in the modified cranial closing we dge as per Oxley et al.16not included, as this technique shouldimmediately achieve cranial cortical alignment upon axial rotation.Abbreviations: mTL, mechanical tibial length; TLA, tibial long axis.150 MOREIRA ET AL . 1532950x, 2024, 1, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14033 by Cochrane France, Wiley Online Library on [05/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licenseright-angle configuration of the cranial tibial wedgecombined with the caudal tibial cortical apex location,described in the traditional CCWO, resulted in a morepronounced distalization of the lower osteotomy andthus bigger sized wedges, to achieve the same axialrotation. Tibial length, though, was calculated as thedistance between a midpoint in the intercondylar tuber-cules and the center of the talus, instead of to a middlepoint in the distal tibial intermediate ridge, as describedby Wallace et al.21The distance between the center ofthe talus and the distal intermediate tibial ridge is argu-ably minimal, and mTL values were normalized, how-ever, slight underestimation of postoperatively mTLreduction may have still been possible.Apart from different ostect omy locations and sagittalalignment, progressive increase in TLA shift with higherFIGURE 6 Box plots showing predicted changes within the 15 tibias of the study, following a cranial closing wedge ostectomy asdescribed by Slocum & Devine.,1Oxley et al.,16Frederick & Cross.,17and Christ et al.,18based on the obtained corrective equations for eachindividual technique. Box plot explanation as for Figure 3.TABLE 2 Mean ± standard deviation of the ostectomy wedge apex location.Wedge angleProximal-distal wedge apex location (%mTL)Caudodistal wedge apex location(% proximal ostectomy length)Slocum & Devine1Oxley et al.16Frederick &Cross17Christ et al.18Frederick & Cross17Christet al.1810/C1412.4 ± 2.1 10.8 ± 2.1 17.7 ± 3.5 19.5 ± 2.3 67.8 ± 3.2 90.9 ± 3.020/C1415.4 ± 2.2 12.5 ± 2.2 17.8 ± 3.5 19.1 ± 2.2 68.6 ± 3.2 87.1 ± 3.730/C1418.5 ± 2.5 13.4 ± 2.0 17.9 ± 3.6 18.9 ± 2.0 69.5 ± 3.9 84.9 ± 4.940/C1422.0 ± 2.9 14.4 ± 1.8 17.3 ± 4.8 18.8 ± 2.0 70.5 ± 4.1 83.7 ± 6.250/C1426.5 ± 3.7 15.4 ± 1.7 18.3 ± 3.6 18.9 ± 1.9 74.1 ± 4.2 84.6 ± 6.760/C1433.2 ± 5.3 16.4 ± 1.8 18.4 ± 3.7 19.0 ± 2.0 76.1 ± 3.9 86.8 ± 7.270/C1444.8 ± 7.7 17.8 ± 1.8 18.7 ± 3.7 19.4 ± 2.0 79.0 ± 3.8 90.6 ± 7.0Note: Proximal-distal location represented the vertical eccentricity of the wedge apex from the intercondylar eminence; values normalized as a percent age ofthe original mechanical tibial length. Caudodistal location, was used to represent cranial eccentricity of the wedge apex from the proximal osteoto my cutmarker; values normalized as a percentage of the full virtual proximal ostectomy length. Craniocaudal apex location not included for the cranial clo sing wedgeas per Slocum & Devine or Oxley et al., as in these techniques, the ostectomy apex is located either at the caudal cortex1or immediately cranial to it.16Abbreviation: mTL, mechanical tibial length.MOREIRA ET AL . 151 1532950x, 2024, 1, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14033 by Cochrane France, Wiley Online Library on [05/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licenseangled wedges may offer an explanation to the range ofwedge angles recommended and mean postoperative TPAsreported.7,12 –16In this study, a shift in corrective wedgeangle was observed at TPA values of 37.5/C14, 36.1/C14,3 3 . 9/C14and34.8/C14for the Slocum and Devine,1Oxley et al.,16Frederickand Cross17and Christ et al.18techniques, respectively. Atthese values, the wedge angle required to achieve a postop-erative TPA of 5/C14converts from a value less than the TPA,to one greater. As most articles report mean or median pre-operative TPAs below these values, it would then beexpected for those authors t o find wedge angles slightlylower or equal to the preoperative TPA to be effective atcorrecting the preoperative TPA.7,12,14 –16Ostectomizedwedges have also been traditionally calculated through asingle corrective value (e.g., TPA-5 =wedge angle) regard-less of TPA value and may offer an explanation to the widerange of postoperative TPAs reported within these stud-ies.7,12,14 –16Nonetheless, the concept that TLA shiftimpacts the end TPA and that wedge size calculation basedon TPA –TPA Target could lead to an undercorrection hasalready been suggested by several authors.12,13,16Surgical planning of each CCWO was to somedegree adapted from the original description and stan-dardized amongst techniques to reduce variability andallow a more direct comparison between procedures.The proximal ostectomy location was chosen to improvepractical applicability, as growing popularity for thislocation within orthopedic surgeons was suspected,given the current evidence that less TLA shift isexpected with decreased vertical eccentricity and cranialcortical alignment.12Most adaptations were minor, withthe three mCCWO already describing a juxta-articularostectomy with cranial cortical alignment. Major adap-tations were only undertaken in the traditional CCWOas the ostectomy was originally described at the level ofthe distal tibial tuberosity, with caudal corticalalignment.1Each technique was investigated up to 70/C14, to achievea greater spread of data and because Frederick and Crossreported two animals with a preoperative TPA > 60/C14,within their study.17Animals in this study were pur-posely selected to introduce variability and allow thestudy to have a wide range of application. However,the potential introduction of a selection bias cannot beexcluded, as these animals were selected within a limiteddatabase with only one presenting the diagnosis of CrCLrupture and only one tibia presenting an extreme TPA(eTPA) of 38.7/C14. While the introduction of errors in thegeneration of an equation based on the sequential underand overcorrection of TPAs cannot be excluded, the pre-dicted TPAs of all tibias in this study were within theideal 4 –6/C14range. This would suggest good reliability inthe generated corrective equations for tibias within thestudied range of TPAs. However, as previously men-tioned, this study only included patients with a maxi-mum TPA of 38.7/C14, thus reliability of the generatedcorrective equations for patients with eTPA cannot beinferred.The in silico nature of this study was considered bothan advantage and a limitation. It allowed for a directcomparison between different CCWO techniques withoutthe introduction of individual tibia variability and sur-geon effect.22,23Other reported sources of TPA measure-ment variability such as degenerative joint disease,24orradiographic positioning20,25were also eliminated. Lastly,once the base tibias were oriented to give a true lateralimage, the in silico nature of the study allowed formanipulation of the proximal segment without changingthe original tibial position, regardless of technique orwedge angle used, eliminating a further possible sourceof variability. On the other hand, the in silico nature ofthis study did not account for “real world ”technical vari-ants such as the aforementioned surgeon effect, kerf loca-tion and width that could affect the achieved results. Kerfthickness was not considered in this study as its size andlocation would introduce surgical variability and discrep-ancy between planned wedge size and ostectomy gap,thus skewing the results.A further limitation of this study was that 3D-markerplacement was performed by only one author and all mea-surements were performed by a single observer. However,measurement reproducibility is expected to be high, asintraobserver reproducibility has been shown to be excel-lent when measuring TPA using CT.26Also Caylor et al.24reported no statistical difference in TPA measurementsbetween experienced observers on radiographs. Lastly, allmarkers were placed by an experienced surgeon and theircoordinates within the y and z planes simply followed themanipulation of the proximal segment as described pereach CCWO technique.1,16 –18We concluded that all CCWO techniques lead to vari-ous degrees of TLA shift that significantly affected theend TPA. By accounting for the TLA shift, the generatedequations have the potential to improve the accuracy ofsurgical planning. Future studies should prospectivelyaim to assess the viability of the generated equations inimproving the surgeon's ability of achieving the planned4–6/C14target TPA.AUTHOR CONTRIBUTIONSMoreira LR, DVM, PgCertSAS, MRCVS: Study design;data acquisition, analysis and interpretation; manuscriptpreparation and revisions; figure illustration. Sparks T,GradIS, PGCert MSc, MSc, PhD: Statistical analysis; fig-ure illustration. Ogden DM, BVSc, DACVS: Study con-cept and design; data acquisition, analysis and152 MOREIRA ET AL . 1532950x, 2024, 1, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14033 by Cochrane France, Wiley Online Library on [05/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licenseinterpretation; critical revision of manuscript. All authorsgave their final approval of the submitted version.FUNDING INFORMATIONLinnaeus Veterinary Limited supported the costs of theOpen Access Publication Charges.CONFLICT OF INTEREST STATEMENTThe authors declare no conflict of interest related to thisreport.ORCIDLuis R. Moreirahttps://orcid.org/0000-0002-0244-7901

Answer 32

This report documents several modified hemi -pelvectomy techniques not previously described, in -cluding concurrent partial sacrectomy and/or verte -brectomy, hemipelvectomy excisions crossing midline with concurrent amputation, and hemipelvectomy abdominal closure without native local muscular tissue or mesh, with overall low incidence of major intra- and post-operative complications and good functional outcomes in the majority of animals. The outcomes of these dogs and cats challenge several widely held notions, including tolerable proportion of sacrum that can be excised, potential for function -al compromise with disruption of the contralateral pelvic structures when concurrent limb amputation is performed, and the requirement for reconstruction of the resulting hemipelvectomy abdominal defect with local muscular tissues or mesh.Most dogs that received modified hemipelvec -tomy with partial sacrectomy and/or vertebrec -tomy had good short-term outcomes, though 4 of 11 dogs had reported mobility concerns postop -eratively. Anecdotally, up to one-third of the sa -crum in width (with osteotomy through the sacral foramina) can be safely excised without functional complication, though no prior reports of concurrent partial sacrectomy with hemipelvectomy have been published in dogs or cats.15 In the present report, 2 dogs had partial sacrectomy excisions that were slightly off midline, with just less than one-half of the sacrum excised in that region. Both dogs had adequate mobility at the time of discharge sev -eral days postoperatively. However, 1 dog was lost to follow-up shortly after discharge, and the other dog experienced an acute decline in mobility associ -ated with an L7 body fracture and was euthanized 2 weeks postoperatively. The authors postulate that the L7 fracture may have been associated with al -tered biomechanics and weight bearing associated with excision of nearly half the sacrum in addition to hemipelvectomy. Therefore, although 2 dogs in this report had partial sacrectomies presumed to be greater than one-third of the sacral width, based on these cases there is no evidence to support the tol -erance, overall safety, or long-term functional out -come for modified hemipelvectomy with this more extensive partial sacrectomy procedure. In fact, this data supports the potential for major postoperative complication in the form of vertebral fracture follow -ing partial sacrectomy of nearly half the sacrum in conjunction with hemipelvectomy. Additional data is needed, and the authors recommend proceeding with caution in more extensive partial sacrectomies. However, of the dogs that underwent partial sacrec -tomy with excision of one-third or less of the sacral width, overall good functional outcomes were seen in all dogs. Only 1 dog with partial vertebrectomy developed significant mobility concerns, and this dog had tumor recurrence within the vertebral ca -nal such that the mobility compromise was associ -ated with primary disease recurrence rather than the vertebrectomy/hemipelvectomy procedure itself. Therefore, although no significant mobility concerns following modified hemipelvectomy with partial sa -crectomy/vertebrectomy were definitively associated with the procedure itself, one case was attributed to disease recurrence and another patient experienced an acute postoperative complication in the form of vertebral fracture, which may have been associated with altered biomechanical forces on the axial skel -eton following extensive partial sacrectomy/hemi -pelvectomy. Furthermore, several cases had relatively short follow-up, and additional data is needed.The outcomes of the dogs and cats that un -derwent modified external hemipelvectomy cross -ing midline allow for several important conclusions. Although there is a theoretical functional concern involved with disrupting the contralateral pelvic os -seous structures and muscle attachments when con -current limb amputation is performed (ie, anatomical disruption of the only remaining pelvic limb support structures), all dogs and cats with modified hemipel -vectomy excisions crossing midline had concurrent amputation, and none had postoperative function or mobility compromise reported. The extent of contra -lateral excision varied, and all animals had excision of pelvic components within the mid or medial third of the contralateral pelvis such that no conclusions can be drawn regarding more extensive contralat -eral hemipelvectomy excisions with amputation. In addition, with osseous excisions nearing or crossing ventral midline, iatrogenic trauma of the urethra and rectum is a possible complication.2,3,15 However, no dogs or cats in the present study experienced any urethral or rectal complications. It remains impor -tant to protect these structures intraoperatively due to their proximity to osteotomies of the pubis and ischium; placement of urethral catheters, rectal sy -ringe cases or tampons, and surgical retractors deep to the site of osteotomy transection can be utilized for these purposes to limit these complications.Finally, regarding the subset of animals that underwent modified hemipelvectomy (the major -ity being total) without primary closure of muscular tissues or use of a local muscle flap for closure of the abdomen, these animals all experienced routine recoveries without any major complications or mo -bility concerns reported. No incidence of abdominal or perineal herniation, septic peritonitis, or major wound healing complications occurred. These find -ings support that in select cases, closure of subcu -taneous tissue and skin alone or in conjunction with native omentum or mesh for a deep closure layer can be well tolerated without complication, and that use of local muscular tissues is not required for abdomi -nal closure in every hemipelvectomy case.The largest study on traditional hemipelvectomy in dogs and cats reported intraoperative complica -tions in 8 of 100 (8.0%) animals and postoperative complications in 12 of 96 (12.5%) animals.3 If the Unauthenticated | Downloaded 10/08/23 06:32 AM UTC8 CLASSIC and Accordion complication schemes are extrapolated to that data, intraoperative complica -tions were grade 1 in 5 dogs, grade 2 in 2 dogs, and grade 3 in 1 dog, and postoperative complications were grade 1 in 10 dogs, grade 2 in 1 dog, and grade 3 in 1 dog. In the present modified hemipelvectomy cohort, intraoperative complications were reported in 3 of 23 (13.0%) cases and were all grade 1, and postoperative complications were reported in 8 of 23 (34.7%) animals, though only 2 of 23 (8.7%) ani -mals had grade 3 or 4 postoperative complications. It is difficult to make direct comparisons between the complication incidence reported in the current co -hort of animals undergoing modified hemipelvecto -my procedures relative to that in the Bray et al study of animals undergoing traditional hemipelvectomy procedures for several reasons.3 First, the method of intra- and postoperative complication recording and grading was different between the 2 data sets; though we attempted to extrapolate the available data in the Bray et al study to the complication-grad -ing schemes used in the present cohort for compari -son, there is potential for error.3 Second, the present modified hemipelvectomy cohort may represent a different population compared with that in the Bray et al study due to the more extensive nature of local disease, resulting in the indication for these modified and more extensive hemipelvectomy techniques.3 If the complication comparisons are accurate and not associated with incomplete information in different retrospective studies, it would appear that the post -operative complication rate in the present cohort of animals undergoing modified hemipelvectomy tech -niques may be greater than that previously reported for traditional hemipelvectomy techniques. Howev -er, it is important to consider the potentially more extensive nature of local disease that necessitated modified hemipelvectomy techniques in the pres -ent modified hemipelvectomy cohort compared with the Bray et al traditional hemipelvectomy cohort.3 Ultimately, though, the reported incidence of major perioperative complications (grade 3 or 4) was rela -tively low (8.7%) in this modified hemipelvectomy cohort, though larger sample sizes and prospec -tive data with standardized follow-up are needed to definitively determine the risk of perioperative complications relative to each of these modified hemipelvectomy techniques.This study had several limitations. First, due to the retrospective nature, complete clinical informa -tion was lacking for some patients. Also, given the small sample size of animals in each subgroup of modified hemipelvectomy techniques, it was not possible to perform statistical analyses with regard to risk factors for complications or outcomes due to the risk for error. Five patients were lost to follow-up, and postoperative pelvic imaging was rarely available in these animals, such that the exact extent of excisions could not be determined in many cases. In addition, the population varied widely relative to neoplastic disease, management, and follow-up. Subsequently, prognostic information regarding sur -vival times relative to surgical procedure cannot be ascertained, and specific outcome data may be at -tributed to a multitude of differences associated with patient and disease variables rather than modified hemipelvectomy technique. Instead, survival and follow-up data have been provided (Supplementary Table S1) to give information on duration of follow-up for these patients relative to their functional out -comes and complications. Finally, selection bias may have occurred because all cases were contributed by referral academic institutions, and patient and client factors likely influenced the types of treatments ad -ministered and follow-up data available.In conclusion, this report represents the first documentation of dogs and cats undergoing modi -fied hemipelvectomy with concurrent partial sacrec -tomy, partial vertebrectomy, external hemipelvec -tomy excisions crossing midline, and reconstruction techniques not utilizing muscular tissues or mesh for body wall closure. The outcomes of these animals lend support to use of these techniques in dogs and cats when indicated, and based on these cases, dog -ma regarding tolerable hemipelvectomy procedures and constraints should be reconsidered. Overall, these modified hemipelvectomy techniques appear to be well tolerated, with a low incidence of major complications, and can result in adequate functional outcomes. Additional studies with larger numbers of dogs and cats undergoing these modifications are needed to gain more information and to determine the tolerable extent of partial sacrectomy/vertebrec -tomy and contralateral osseous excision, as well as to explore scenarios in which closure with subcutane -ous tissue and skin alone or with omentum may not be well tolerated.AcknowledgmentsThe authors received no grant funding in association with the cases described in this report. The authors declare that there were no conflicts of interest.The authors thank Chrisoula Toupadakis Skouritakis for as -sistance with composing Figures 1 through 3 for this manuscript.

Answer 33

Unilateral DPO may restore long-term joint kinetics on thesurgically treated limb in patients suffering from juvenile hipdysplasia. All dogs in this case series achieved a total pressureindex and GLS on the surgically treated hip comparable tonormal limbs, as described in the literature.13Indications forunilateral DPO were hip laxity and lameness due to hipdysplasia without radiographic evidence of osteoarthritisin the surgically treated limb. Double pelvic osteotomywas not performed on the contralateral limb due to radio-graphically evident osteoarthritis and therefore managednon-surgically in all but one dog (case 6).The GAITRite system provides a quantitative assessmentof lameness, which is superior to the ability of a clinician todiagnose lameness.14Total pressure index is the sum of thepeak pressures that are recorded from each sensor as a pawstrikes the sensor during contact with the mat.14Fahie andcolleagues13demonstrated there was no difference betweenthe total pressure index hindlimb ratio compared with thetraditionally accepted 60/40 forelimb/hindlimb ratio and the20/20 left/right hindlimb ratio. As such, GLS was utilized inTable 2 British Veterinary Association Hip Dysplasia Scheme scores (BVA-HD) for untreated and DPO-treated hips for each casepreoperatively (pre) and postoperatively (post)Case 1 Case 2 Case 3 Case 4 Case 5 Case 6 Median RangeBVA-HD untreated (pre) 20 23 19 10 19 10 18.88 10 –23B V A - H D u n t r e a t e d ( p o s t ) 4 73 94 71 53 3N Aa39.00 15 –47BVA-HD DPO-treated (pre) 18 12 10 11 13 10 11.63 10 –18B V A - H D D P O - t r e a t e d ( p o s t ) 1 7 142122 . 0 0 1 –17Abbreviations: DPO, double pelvic osteotomy.aThis limb underwent total hip replacement; therefore, calculation of BVA-HD score was not performed.Fig. 1 Box plots showing (A) median and interquartile range of British Veter inary Association Hip Dysplasia Scheme (BVA-HD) preoperative andpostoperative of untreated (dark) and surgically treated (light grey ) hips; the dot in the postoperative surgically treated group signi ﬁes anoutlier, and ( B) median and interquartile range of GAIT4 Dog Lameness Scores (GLS ) of untreated (dark) and surgically treated (light grey) hips..our population in which dogs without lameness should haveGLS scores of approximately 100 in all limbs, whereas dogswith lameness have scores less than 90 in the lame limb.13The lack of signi ﬁcant difference between the GLS of treatedand untreated hips is likely a type II error and this warrantsfurther investigation in a larger population.Case 6 underwent staged unilateral DPO and contralateralTHR, and gait analysis at follow-up suggested lameness of theTHR limb. The asymmetry of the hindlimbs may have poten-tially affected the kinetic outcome of this case causing afunctional lameness rather than a pathologic lameness. Thisresult must therefore be interpreted with caution. Improvedkinetic outcomes have been evaluated in dogs with unilateralcemented THR using pressure sensitive walkways15andstanding bodyweight distribution.16Given these previousreports, one would expect the THR limb to have a similar orbetter kinetic outcome than the contralateral limb. To theauthors ’knowledge, there are no studies directly comparingthe kinetic outcome of unilateral DPO and contralateral THR;however, this case suggests that this may be warranted toevaluate the value of THR in this scenario.This case series suggests a trend of improvement inradiographic scores of the surgically treated hip followingunilateral DPO surgery and concurrent worsening of scoresin untreated hips. The lack of any signi ﬁcant differencessuggests that larger prospective studies are required.In addition to having a very small sample size, thisstudy has several limitations. The disparity in postoperativeradiographic scores between the surgically treated anduntreated limbs is comparable to that of postoperativekinetic outcomes (►Fig. 3 ). Although one can appreciate acorrelation in outcome, the magnitude of improvementunfortunately cannot be compared without preoperativekinetic data, which was unavailable. To address this limita-tion, we propose a prospective study where preoperative andpostoperative kinetic data are collected for review.Another limitation is that the temporospatial mat can onlyassess ground reaction forces in the vertical direction. Forceplate analysis of the limbs would provide more informationin relation to mediolateral and craniocaudal forces; however,there is inconsistent data for mediolateral ground reactionforces in the literature,17limiting its usefulness in this paper.Furthermore, the fact that the untreated limb was deemed apoor surgical candidate makes it a poor direct comparisonagainst the DPO treated limb. In almost all cases, theuntreated limb was still the cause of the dogs ’lameness atfollow-up and likely contributed to the total pressure indexand GLS of the surgically treated limb. While a true controlcohort may be challenging to recruit, there may be dogs thatﬁt inclusion criteria for a control group that are managedmedically due to the ﬁnancial cost of DPO and THR surgery.Lastly, our study population had a large age range at initialpresentation with one patient being 13 months old whenﬁrst presenting. Although DPO surgery has traditionallybeen reserved for dogs 4.5 to 9 months old,2there isincreasing evidence that DPO surgery may be performedwith good clinical outcomes in dogs more than or equal to10 months old, assuming little or no evidence of radiographicFig. 2 Ventrodorsal hip-extended radiographs of case 3 taken preopera-tively (A), immediately postoperatively (B), ﬁfty-ﬁve months postoperatively(C) and eighty-seven months postoperatively (D). Note the minimal devel-opment of osteoarthritis of the DPO-treated hip at follow-up (L) comparedwith the marked and progressive osteoarthritis of the untreated up (R).Fig. 3 Ventrodorsal hip-extended radiographs of case 5 takenpreoperatively (A), immediately postoperatively (B), eleven monthspostoperatively (C) and fourty-six months postoperatively (D). Notethe good coverage of the femoral head within the acetabulum in theDPO-treated hip and minimal deve lopment of osteoarthritis in theDPO-treated limb (R) compared with the minimal femoral headcoverage within the acetabulum a nd marked, progressive osteoar-thritis of the untreated hip (L)..osteoarthritis.4We acknowledge, however, that the sensitiv-ity of radiography in detecting osteoarthritic changes injuvenile dogs is inferior to that of arthroscopy,18whichwould be ideally included in future prospective studies ofthe same nature.Most of the dogs in this study are yet to undergo THR onthe untreated hip, which is still responsible for clinicallameness in ﬁve out of the six dogs in this study. In ourpopulation, unilateral DPO has preserved the surgicallytreated hip; however, the contralateral hip is still poorlymanaged without salvage procedures.ConclusionsThis study has demonstrated that the kinetic outcomes of theDPO meet expected total pressure index and GLS of normallimbs. In our population, the postoperative radiographicoutcomes correlate well with postoperative kinetic out-comes; however, larger prospective studies are required todetermine signi ﬁcance of improvement.

Answer 34

In this study, the TPLO-M procedure performed with the aid ofpre-contoured locking plates on bone models allowed concur-rent levelling of the tibial plateau and medialization of theproximal tibial segment. In the previous clinical study byFlesher and colleagues, T style TPLO plates were manuallycontoured to ﬁt the step in the proximal tibia after proximalsegment medialization because the pre-contoured plate uti-lized in our study had not yet been developed.10Manualcontouring of TPLO plates to ﬁt the proximal tibia afterTPLO-M is somewhat complex and tends to result in anincreased in plate to bone distance, which may result inweakening of the bone-plate construct and an increase insurgical time. The pre-contoured implants used in this studyallowed subjectively easy plate application to the proximaltibia after TPLO-M without the need for plate contouring.Another difference in the surgical technique utilized in thisstudy as compared to the technique in Flesher ’s study is thatthe TPLO procedure in this study was performed with jigassistance.10We found that use of the jig allowed medializa-tion of the proximal tibial segment while maintaining tibialangular alignment in the front plane and tibial torsionalalignment in the axial plane.In this study, the magnitude of proximal segment medi-alization increased as the plate offset increased from 4 to6 mm. We did not identify any differences in the amount ofmedialization achievable with a speci ﬁc plate offset based onbody weight of the patient from which the tibial model wasobtained. Based on these ﬁndings, we rejected the ﬁrst partof our hypothesis (that patient body weight would affect theamount of medialization achieved with a speci ﬁc plateoffset). Based on our ﬁndings, regardless of patient weighttheþ4 mm offset plates allowed a mean translation of2.93 mm, while the þ6 mm offset plates allowed a transla-tion of 5.03 mm. These values may be useful to keep in mindduring the plate selection portion of preoperative surgicalplanning for TPLO-M.Platetojointdistance was not correlatedwith theamountofproximal segment medialization in this study. Since the prox-imal tibia in the frontal plane is triangular in shape, it stands toreason that the more distally the plate is positioned on theproximal segment, the greater the amount of medializationthat should be achievable. In this study, our efforts to stan-dardize plate position on the proximal segment along with thesmall number of specimens in each group may have hiddenanyeffect that platepositioning on the proximal tibial segmentmay have on amount of medialization achievable.Plate to bone distance distal to the osteotomy increases asthe magnitude of proximal segment medialization increases.Excessive distance between the bone and the plate togetherwith a decrease in bone segment apposition at the osteotomysite could result in osteotomy instability and delayed boneunion. Further clinical studies should be performed to assessany effect these pre-contoured bone plates may have onosteotomy healing time after TPLO-M.Medialization of the proximal tibial segment results in adirect reduction in bone apposition at the level of theosteotomy site (APP). Based on general orthopaedic princi-ples, the maximum acceptable bone segment translationshould leave at least 50% bone segment apposition at thelevel of the osteotomy line in the frontal plane to facilitateacceptable bone healing.15The mean APP value in groupsK5O4, K10O4 and K10O6 was higher than 50%, while meanAPP in group K5O6 was 39%. The less than 50% appositiondocumented in group K5O6 represents excessive translationof the proximal segment which might compromise bonehealing in a clinical patient. When the þ6mm offset plate isselected for use in a patient weighing less than 10 kg, themaximum acceptable proximal segment medialization valueshould be calculated preoperatively by measuring the widthof the tibia on the craniocaudal radiographic view at the levelof the planned osteotomy and dividing this width in half. It isrecommended that this calculated medialization value notbe exceeded during surgery.In the clinical study by Flesher and colleagues,10dogswith grades I, II and III medial patellar luxation were treatedwith a mean proximal segment medialization (MI) of 20%meaning 80% apposition was retained at the osteotomy siteon average.10Magnitude of proximal tibial segment medi-alization in Flesher ’ss t u d y10was subjectively determinedduring surgery, similar to the subjective assessment of howmuch to move the tibial tuberosity during tibial tuberositytransposition.5In most clinical dogs with low to moderategrades of medial patellar luxation, the need for more than50% medialization of the proximal segment is unlikely, andin the more severe cases of grade IV medial patellar luxa-tion, a corrective osteotomy of the femur is typicallyrecommended.16,17Maintaining the centre of the radialosteotomy blade over the centre of the sti ﬂe joint to resultin a relatively proximally positioned osteotomy may also beuseful to help maintain a higher APP after proximal segmentmedialization, as the tibial width in the frontal planeincreases proximally.Tibial plateau levelling and medialization osteotomyresulted in levelling of the tibial plateau in both controland treated groups without evidence of signi ﬁcant differ-ences in ﬁnal TPA between groups. Hence, we partially acceptthe second portion of our hypothesis and conclude thatmagnitude of proximal segment medialization did not affectﬁnal TPA in this bone model study.Medialization of the tibial plateau resulted in a small but notsigniﬁcant change in mMPTA values in most of the study groups.However, a signi ﬁcant increase in mMPTA was identi ﬁed in theK5O6 group as compared to the control (K5O2) group (mMPTAcontrol group: 88.9 degrees and mMPTA K5O6: 93.3 degrees).Thus, we partially reject the second portion of our secondhypothesis as TPLO-M resulted in an alteration of mMPTA which.was signi ﬁcant in some groups. Medial translation of the proxi-mal tibial segment during the TPLO-M procedure results in aslight medial deviation of the proximal origin of the tibialmechanical tibial axis in the frontal plane and thus tends toincrease mMPTA. Given the same amount of proximal tibialsegment medialization, the shorter the overall length of the tibia,the greater mechanical tibial axis deviation that will result. Thisrationale likely explains why given the same amount of MED withtheþ6mm offset plate, a signi ﬁcant change in the mMPTA wasidenti ﬁed only in the smaller (5 kg) and not in the larger (10 kg)patient tibia model. A small shift in mMPTA associated withTPLO-M was previously reported by Flesher and colleagues in aseries of clinical dogs treated with TPLO-M.10It is important todifferentiate between values that are signi ﬁcant and values thatare clinically relevant. While in this study an alteration in mMPTAof approximately 4.5 degrees was identi ﬁed as being signi ﬁcant,the clinical relevance of small shifts in mMPTA has not beendetermined. The authors ’observation has been that small shifts inmMPTA of the magnitude typically observed in association withTPLO-M have no detectable effect on limb function in clinicaldogs. Additional studies are nee ded to determine what effect, ifa n y ,s m a l ls h i f t si nm M P T Ah a v eo nj o i n tf u n c t i o ni nd o g s .This study has several limitations. This study was per-formed on 3D printed bone models that lacked many anatom-ical features including muscles, tendons, ligaments and otherperiarticular structures. Given this limitation, the results ofthis study should be extrapolated with caution to clinical dogs.We chose to perform this study on bone models to allowsample size optimization and to decrease sample variability(multiple copies of the same tibia). Our results for proximalsegment medialization may differ from what other surgeonsmight achieve, as different surgeons may have different pro ﬁ-ciency levels in performing TPLO-M and may position the platedifferently on the proximal tibial segment as compared towhere the plates were positioned in this study.In conclusion, the þ4mm and þ6mm offset pre-contouredlocking plates should be considered as a reasonable optionfor stabilization of TPLO-M in dogs weighing between 5 and10 kg. The þ6mm offset plate should be used cautiously indogs weighing less than 10 kg since it may allow excessiveproximal tibial segment medialization leading to insuf ﬁcientpostoperative bone apposition at the osteotomy site.

Answer 35

In this study, we demonstrated that regions within origin andinsertion of the CCL in dogs are isometric. The isometric areaon the tibial plateau included the cranial aspect of the medialintercondylar tubercle as well as the cranial intercondylararea, which is the reported insertion of the CCL on the tibialplateau.20The location of the isometric area on the caudo-medial aspect of the lateral femoral condyle was caudal to theCCL anatomical landmark, and it was concluded that theisometric area coincides with the origin of the CCL at thislocation. The locations of the isometric areas on the lateralaspect of the sti ﬂe were craniodistal to the lateral fabella andcranial and caudal to the extensor fossa on the lateral aspectof the tibial plateau. These locations are similar to projec-tions of the origin and insertion of the CCL onto the lateralcortex of the lateral femoral condyle and the lateral aspect ofthe tibial plateau, respectively (►Fig. 1A, F ). The isometriclocations on the lateral aspect of the sti ﬂe have been de-scribed in 2D studies,17–19and their presence is con ﬁrmedusing a 3D model, which also con ﬁrms the isometric locationof the CCL. Minor differences in location between this studyand previous 2D studies are likely due to the isometric areaidenti ﬁed in this study not being at the geometric center ofthe insertion of the CCL on the femur.The CCL in dogs can be divided into a larger caudolateralpart that is taut when the sti ﬂe is extended but becomesloose when the joint is ﬂexed and a craniomedial part of theCCL that is taut over the entire range of motion of the sti ﬂe.20The craniomedial part of the CCL is orientated between thecraniodorsal aspect of the femoral attachment and thecraniomedial aspect of the tibial attachment,20and it is likelythat this is the most isometric part of the CCL. Changes intension would not be expected to occur in collagen ﬁberbundles connected to isometric points on the femur andtibia, and it can be concluded that some parts of the CCL areless isometric than others. For this reason, we speculate thatthe sizes of the isometric areas described in this study arelikely smaller than the actual footprint of the origin andinsertion of the CCL on the femur and tibia. Unfortunately,the diameter of the CCL in the dog used in this study was notmeasured and normal values for the diameter of the CCL havenot been reported. The lack of isometry in some parts of theCCL likely explains that moving the sti ﬂe through a full rangeof motion resulted in a maximum 12.5% change in lengthbetween the insertions of the CCL when the insertions werereduced to a single point.19In the same study, it was foundthat an estimation of the centers of the insertions of the CCLwas less isometric than a point on the fabella and theinsertion of the CCL on the tibia.In the dog, insertions of the CCL on the femur and tibiahave been assumed to be isometric, reduced to a singlepoint, and projected onto the lateral aspect of the sti ﬂet oidentify isometric points for both intracapsular34andextracapsular repair35of the ruptured CCL. In humans,cadaveric studies using various techniques in intact andanterior cruciate ligament de ﬁcient knees have concludedthat no two points are absolutely isometric; however, neari s o m e t r yc a nb ed e ﬁned within certain limits.1Near isom-etry has not been de ﬁned in the dog, and the choice of lessthan 0.2 mm to identify isometric points in this study wasarbitrary. However, using this criterion, isometric areaswere identi ﬁed at the insertions of the CCL as well as onthe lateral aspect of the sti ﬂe. When the change in lengthwas increased to less than 0.4 mm, more points were foundin previously identi ﬁed areas; however, no additional areaswere identi ﬁed, and the area of the footprint did notchange. Decreasing the change in length to less than0.1 mm resulted in less pairs of isometric points, andwhen these points were connected with a straight linethe location of the isometric pairs within the isometricareas was revealed (►Fig. 2 ).The footprint of the insertion of the CCL on the tibialplateau is described as being “comma shaped ”and coin-cides with the cranial intercondylar area with some ﬁbersinserting on the medi al intercondyla r eminence.20Theisometric footprint found in this study starts at the medialintercondylar emi nence and includes th e cranial intercon-dylar area; however, it extends to the craniomedial edge ofthe tibial plateau. The presence of a larger isometric area onthe tibial plateau is supported by the ﬁndings in peoplehaving undergone surgical repair of the anterior cruciateligament that while placement of the graft on the femur iscritical to surgical success, placement on the tibia allows farmore latitude.1The femoral origin of the CCL is on a fossalocated caudally on the axial aspect of the lateral condyle ofthe femur and is described as having a “segment of a circle ”.shaped footprint20with a convex caudal aspect and awedge-shaped cranial aspect. The isometric area identi ﬁedat the insertion of the CCL on the femur in this study issimilar to the shape of the footprint, but smaller thanexpected for a 26-kg dog, leading to the conclusion thatonly a part of the insertion of the CCL on the femur isisometric.Extracapsular repair of the ruptured CCL was described13and modi ﬁed with more recent techniques making use ofisometric points on the lateral aspect of the sti ﬂe.16,17,35Theﬁndings of this study appear to validate all previousstudies. Lateromedial radiographs acquired at ﬁve jointangles found the least change in distance between a pointdistal to the fabella and points on the lateral aspect of thetibial plateau in the region of the long digital extensor.16The optimal con ﬁguration of an extracapsular prosthesis,based on suture tension, was shown to be between thelateral fabella and a pair of bone tunnels located in theproximal tibial crest cranial to the extensor fossa.18In asimilar study, least variation in tension was recorded inmaterial placed between a location distal to the fabella andon the lateral aspect of the tibial plateau caudal to theextensor fossa.17However, in an in vitro kinematic study, alocation distal to the fabella and on the lateral aspect of thetibial plateau cranial to the extensor fossa resulted in theleast change over the full range of sti ﬂe angles.19Consider-ing all this and the long isometric area on the lateral aspectof the tibial plateau identi ﬁed in this study, it is possiblethat two prostheses are required to restore normal sti ﬂebiomechanics.This study is limited in that it is an in vitro cadaveric studyperformed on a single intact unloaded specimen, and theﬁndings will have to be validated using a range of dog breeds.It is unclear how closely the movement of a cadaveric sti ﬂeapproximates physiological movement, and it is likely thatthe movement in a loaded specimen would be different fromthe movement reported in this study. In addition, manuallymoving the tibia and resting the cranial aspect of the tibia ona dowel during data collection are further limitations of thisstudy. However, with all the limitations listed above, isomet-ric areas were identi ﬁed at the insertions of the CCL and onthe lateral aspect of the sti ﬂe.In conclusion, this is the ﬁrst 3D study to demonstrateisometric areas at the origin and insertion of the CCL and onthe lateral aspect of the sti ﬂe. This information may beimportant for the development of intra-articular and extrac-apsular techniques of CCL repair.

Answer 36

Stiﬂe stabilization, such as a TPLO, is an elective surgicalprocedure with the goal of returning dogs to pre-cruciatetear mobility and activity levels, allowing for a great qualityof life.2Theﬁnancial investment for surgical stabilization is acommitment for owners. The goal of this study was to providethe prevalence of a contralateral CCLR in dogs 8 years of ageand older to aid in owner ’s decision-making process whenpursuing medical versus surgical treatment. A total of 159/831dogs experienced a contralateral CCLR within the follow-upperiod resulting in a prevalence of 19.1% (95% CI: 16.6 –22.0%).This value falls below previous reports investigating CCLR indogs which found that contralateral CCLR occurred in 33.1% ofdogs (mean; range: 13 –48%).13,15 –20Most of these studiesfocused on a broad range of breeds, weight and age with apopulation size of 166 dogs (mean, range: 94 –511 dogs). Themost referenced contralateral CCLR study by Buote and col-leagues is frequently utilized in surgical consultations withowners, stating the risk of contralateral CCLR is approximately50% within approximately 6 months upon diagnosis of initialﬁrst-side CCLR.19In this 2009 study of 94 Labradors themedian age was 4.8 years with a median body weight ofTable 1 Descriptive date for CCLR age of diagnosis and time from ﬁrst CCLR to contralateral CCLRAge (in months) atfirst CCLRAge (in months) atcontralateral CCLRTime (in months) from firstCCLR to contralateral CCLRCells with data 831 159 159Mean 110.63 123.76 16.86Median 108.07 119.93 12.90SD 18.51 17.43 13.14SE 0.64 1.38 1.04Shapiro –Wilknormality testp-value0.00 0.00 0.0025th percentile 96.23 111.70 6.5075th percentile 120.07 134.23 24.37Skewness 3.50 0.75 1.29Abbreviations: CCLR, cranial cruciate ligament ru pture; SD, standard deviation; SE, standard error..37.1 kg concluding contralateral CCLR occurred in 45/94 dogs(48%) with a median time to rupture of the contralateral CCLRbeing 5.5 months.19However, our ﬁndings suggest that theadvice given to owners of older medium-large breed dogsdiagnosed with unilateral CCLR regarding the future risk ofcontralateral CCLR should be modi ﬁed.The amount of time from diagnosis of the ﬁrst-side CCLR tothe diagnosis of a contralateral CCLR in our study (median 12.9months) was consistent with previous reports which foundthat contralateral CCLR occurred a mean of 11.2 months(range: 5.5 –16.5 months) after initial ﬁrst-side CCLRdiagnosis.13,15 –20There has been con ﬂicting speculation that dogs thatsustain a unilateral CCLR increase weight-bearing on thecontralateral hindlimb, and thereby increase the risk for acontralateral CCLR to occur. Ragetly and colleagues reported athreefold increase in power generated at the contralateralstiﬂe joint in Labrador Retrievers when a unilateral CCLRoccurs, noting a change at the braking/propulsion ratio from50%/50% in normal pelvic limbs to 33%/66% of the stance phasewith a unilateral CCLR limb.22Theyconcluded that their resultscaptured increased loading of contralateral limbs comparedwith normal limbs associated with greater mobilization of thestiﬂe extensor muscles predisposing the dogs to contralateralCCLR.22Of the 157 cases with contralateral CCLR in our studythere was no statistical impact on the occurrence of a contra-lateral CCLR with regard to time from ﬁrst-side CCLR diagnosisto surgery. Surgery on ﬁrst-side CCLR was overwhelminglyperformed early after the diagnosis, and no statistical correla-tion was found.The risk of age was found to impact contralateral CCLR in thatfor every 1 month increase in age, the odds of contralateral CCLRoccurrence decreased by 2%. To our knowledge there are noprevious studies focused on the risk of contralateral CCLR inaging dogs. It is possible that owners of older dogs may be lesslikely opt for referral and treatment past their primary careveterinarian for contralateral CCLR. Another explanation for thisﬁnding could be that older dogs tend to be less active, whetherthis is due to comorbidities such as osteoarthritis, when com-pared with younger dogs. A speci ﬁc explanation for this ﬁndingwas not observed within this study and likely a prospectivestudy would be warranted for further investigation.Golden Retriever/mix and Labrador Retriever/mix breedshave been evaluated in previous studies regarding contralat-eral CCLR. This study found the odds of a contralateral CCLRfor Golden Retriever/mix were found to be 53% (OR: 1 –0.47¼0.53, 95% CI: 0.24 –0.92) less compared with non-Golden Retrievers and 42% (OR: 1 –0.58¼0.42, 95% CI:0.38 –0.86) less odds for Labrador Retriever/mix comparedwith non-Labrador Retrievers (►Table 3 ). In a study byTable 3 Factors signi ﬁcantly associated with contralateral CCLRIndependentvariableXRegressioncoefficientb(i)StandarderrorSb(i)Wald testp-valueOdds ratioExp(b(i))Lower 95%confidencelimitUpper 95%confidencelimitIntercept 0.8577 0.7730 0.22 2.36 0.59 9.43GoldenRetriever/mix/C00.7510 0.3418 0.03 0.47 0.24 0.92LabradorRetriever/mix/C00.5466 0.2032 0.01 0.58 0.39 0.86Age (in months)atﬁrst CCLR/C00.0190 0.0065 0.00 0.98 0.96 0.99Abbreviation: CCLR, cranial cruciate ligament rupture.Table 2 Descriptive data for follow-up tableABCDCells with data 831 831 159 145Mean 116.96 117.19 100.78 102.47Median 112.73 112.65 101.90 102.10Standard deviation 48.47 48.04 47.98 48.0725th quartile 75.40 75.54 60.23 62.7275th quartile 157.77 157.89 142.07 144.35Shapiro –Wilk normality test p-value 0.00 0.00 0.00 0.00Abbreviations: CCLR, cranial cruciate ligament rupture; TPLO, tibial plateau levelling osteotomy.Note: Key; A. follow-up time (months) from ﬁrst-side CCLR diagnosis to end of data capture (6/1/2021), B. follow-up time (months) from ﬁrst-sideTPLO surgery to end of data capture (6/1/2021), C. follow-up time (months) from second-side CCLR diagnosis to end of data capture (6/1/2021),D. follow-up time (months) from second-side TPLO to end of data capture (6/1/2021)..Grierson and colleagues, no signi ﬁcant difference was foundbetween breeds; however, Golden Retrievers were less likelyto experience bilateral CCLR (36/511, OR: 0.28, CI: 0.08 –0.98,p¼0.047).20The increased risk of contralateral CCLR inLabrador Retrievers has been well documented in Buote ’sstudy; however, our study found Labrador Retrievers to havedecreased risk compared with other breeds.19The differencebetween our study and a previous study19would be the ageof the study population. It could be hypothesized thatLabrador Retrievers are at higher risk of CCLR at a youngerage; however, further investigation is warranted.A major limitation is the retrospective nature of this studyand loss to follow-up. Although dogs were re-examined at the 8to 12-week postoperative time point, they were only re-pre-sented beyond this if an issue arose. To include a large samplesize, the range of study data years was substantial (2002 –2017).This prohibited the ability to contact owners directly for accu-rate follow-up information including if dogs were deceased, ifowners moved and were no longer registered with the practiceor if they declined referral for suspected contralateral CCLR.During the follow-up period, this specialty centre was the soleoption for access to board-certi ﬁed orthopaedic surgeons with-in a 3-hour driving radius. Although there is a risk that afterinitial CCLR the patient could have been seen elsewhere by anorthopaedic surgeon for a contralateral CCLR, this is consideredunlikely by the authors. All data were collected from a singlereferral hospital, making the population inherently biased.Differentiation between partial and complete CCLR wasnot differentiated in the medical record, surgery reports, norwas accurate historical medical documentation for whenclinical signs (lameness) began. As previously stated, preop-erative radiographs were performed in all cases along withradiographs of the contralateral limb; however, due to theextent of the dataset range from 2002 to 2017, they wereunavailable for review and inclusion in this study. For thisreason, the date of ﬁrst-side CCLR was documented basedupon the date of diagnosis by a board-certi ﬁed surgeon.The prevalence of contralateral CCLR in medium-large breeddogs 8 years of age or older is 19.1% and the risk decreases astheyage. Golden Retriever breeds and LabradorRetriever breedswere also found to be at decreased risk of contralateral CCLRwithin this study population. This is valuable information thatcan be shared with owners during orthopaedic consultationsand in turn helps owners in their decision-making process forpursuing surgical intervention in an older dog.

Answer 37

This is the first retrospective, multicentric study with the aim of documenting the use of the WIC following a variety of surgical procedures in cats, investigating any complications and risk factors associated with catheter placement or LA administration.The results of the study document the versatile and safe use of the WIC for a large variety of surgical proce -dures, for which LA administration was used as part of a multimodal analgesic plan in cats. The WIC was used with different protocols of LA administration, and it was left in place for variable durations.The reported overall complications rate in the pre-sent study was relatively low (13.2%) and all complica-tions were self-limiting. Wound-related complications occurred in 7.8% of cases, the majority of which were observed with the feline injection site sarcoma excision. However, statistical analysis failed to demonstrate significant association between the complications and type of surgery. This result could have been influ -enced by the high number of cases of feline injection site sarcoma removal compared with the other type of surgery (type II error). Feline injection site sarco-mas are locally invasive tumours and require aggres-sive surgical treatment. Radical surgical excision is challenging, with the current recommendations being 5 cm lateral margins and two fascial planes for deep margins.27 This can be associated with a higher incidence of postoperative wound-related complications.In the present study, drugs delivery complications were encountered in 5% of cases. Technical issues (catheter dislodgement and resistance during injection) were reported in seven cases. The external location of the WIC makes it more exposed to mechanical interference during the hospitalisation time. In both human28 and vet -erinary studies,6,23 it has been reported that the catheter Table 2 Simple logistic regression results determining factors associated with all complications after surgical wound infusion catheter placement in catsLogistic regression All complicationsOR 95% CI P valueAge 0.99 0.98–1.00 0.339Gender 2.73 0.70–10.70 0.148Body weight 1.06 0.69–1.61 0.791Type of surgery 1.20 0.69–2.09 0.515Catheter size 0.94 0.53–1.66 0.843Use of a filter 0.44 0.80–2.27 0.332Catheter location (subcutaneous vs intermuscular) 1.15 0.33–3.94 0.820Catheter duration 0.99 0.97–1.00 0.352Type of LA (ropivacaine vs bupivacaine) 0.40 0.84–1.93 0.257LA concentration 0.43 0.12–1.52 0.191LA administration frequency 1.20 0.80–1.80 0.365LA total dose 1.00 0.99–1.00 0.249LA single dose 5.44 1.55–19.10 0.008Use of NSAID 3.78 0.47–30.47 0.211Variables highlighted in bold qualified for inclusion in the multiple regression analysis at P <0.20 (Table 3). OR = odds ratio; CI = confidence interval: reference category used in logistic regression; LA = local anaesthetic; NSAID = non-steroidal anti-inflammatoryTable 3 Multiple logistic regression results determining factors associated with all complications after surgical wound infusion catheter placement in catsLogistic regression All complicationsOR 95% CI P valueGender 2.59 0.64–10.42 0.180LA concentration 0.53 0.13–2.16 0.380LA single dose 5.35 1.52–18.80 0.009OR = odds ratio; CI = confidence interval; LA, local anaestheticKazmir-Lysak et al 5can be dislodged, disconnected or partially blocked at the outlet.The results of the present study suggest that the only risk factor associated with the overall complications was the amount of a single dose of LA delivered through the catheter. A volume higher than 2.5 ml of LA delivered at each administration has been found to be associated with an increased risk of complications. Such a finding should be interpreted cautiously because it does not factor the wound size and the speed of administration relative to the amount of LA administrated. However, it would be logical to assume that a larger volume of LA drugs would require more time to be absorbed and could cause seroma, oedema or wound swelling. This finding is in contrast to the previously published data in human patients29,30 and veterinary medicine23 where the incidence of wound-related complications did not relate to the volume, rate or drug content of the LA infusion.One cat experienced local irritation and another expe -rienced hypersalivation at time of the administration of LA. In both cases, the LA used was bupivacaine 0.5%. Tissue reactions induced by the LA solutions may be one of the factors resulting in pain after application.31 Based on a study conducted on human volunteers, it has been determined that the pain experienced during intramus -cular injection of bupivacaine 0.5% is significantly more intense compared with ropivacaine 0.5%.32 Interestingly, the variance in pain intensity between these two LAs does not appear to be associated with differences in pH.32 Lipid solubility of the LA has also been consid-ered as a factor in the severity of pain on injection.33 This factor provides justification for the observation that bupivacaine, being more liposoluble compared with ropivacaine, may cause greater pain during injection. However, there is insufficient evidence to support this statement in veterinary literature. Although the cause of pain after LA injection is not fully understood, adding a basic solution (typically sodium bicarbonate) to the LA solution before injecting it into the target tissues may decrease the pain on injection.34The hypersalivation that presented in one cat could be compatible with signs of neurotoxicity; however, we cannot completely rule out other causes. Cats are more sensitive to LA systemic toxicity, which can be explained by their reduced hepatic metabolism;35 therefore, there is an existing concern during prolonged administration. Recently, local anaesthetic systemic toxicity associated with bupivacaine administration has been reported in two cats.36,37 In the first case, bupivacaine was acciden-tally overdosed (10 mg/kg) during intrapleural adminis -tration.36 In the second case, bupivacaine was delivered epidurally through an epidural catheter over several days, causing toxicity due to accumulation.37 However, there are no reports of severe neurotoxicity after subcu -taneous or intramuscular administration of LA in cats.The LA drugs used in this retrospective study were bupivacaine and ropivacaine at different concentrations. Bupivacaine and ropivacaine are aminoamide LAs with a slow onset and a long duration of action. Bupivacaine compared to the S -enantiomer ropivacaine, is more lipo -philic and potent than ropivacaine and, consequently, it is more neurotoxic and cardiotoxic.38 In cats, the mean convulsant dose was 3.8 ± 1.0 mg/kg IV and 18.4 ± 4.9 mg/kg IV for cardiovascular collapse.39 In the present study, the administered dose closely adhered to those described in the literature. The recommended doses are 1 mg/kg for bupivacaine, whereas the dose for ropivacaine is 1–2 mg/kg in cats.40In humans, the reported incidence of LA toxicity after different nerve blocks varied across studies, with estimates ranging from as low as 2.5 cases per 10,000 blockades to as high as 10 cases per 10,000 blockades.41–43 Notably, one study recorded no events in over 12,000 blockades.44 The incidence of systemic toxicity in veterinary species is not documented, but is probably very low.11Recommendations for pain management encourage the use of LAs in the majority of surgical procedures.7,8 The combination of LA and systemic opioids not only improves pain management, but also allows a decrease in the opioid dosage, thereby decreasing the risk of adverse effects associated with opioid administration, such as bradycardia, respiratory depression, hypothermia and sedation.5,45,46 LAs have been administered perineurally, epidurally, intrapleurally, intra-articularly and topically to alleviate pain associated with various surgeries in dogs.46–48 There is growing evidence in the human and porcine models that locally applied LAs can also inhibit the inflammatory responses that can sensitise nociceptive receptors and contribute to the development of pain and hyperalgesia.49,50The use of WICs offers an additional benefit by allow -ing repeated LA administration throughout the postoper -ative period. Although postoperative pain score and food intake evaluation were beyond the scope in the present study, a previous study reported that cats receiving LAs infused through wound catheters spent significantly less time in hospital than those that did not, suggesting that the cats became mobile more quickly and took less time to start eating than those on other analgesic regimens.21 Similar results have been observed in human studies, where the use of WICs with LAs led to a reduced hos-pital stay of 2.1 days compared with 3.2 days in control patients who received systemic analgesia alone, resulting in significant cost savings.51 However, further research is needed in both human and veterinary fields to validate this finding.The main limitation of the present study is the retro -spective and multicentric nature with a lack of stand-ardised postoperative reporting. Multiple protocols and different LAs (bupivacaine and ropivacaine) were used 6 Journal of Feline Medicine and Surgery at different concentrations. Moreover, the study popula -tion included patients undergoing a wide range of pro -cedures, introducing additional confounders related to underlying surgical pathology and technique.Further prospective studies are required to evaluate the efficacy of postoperative analgesia, to determine the optimal amount and concentration of LA drug adminis -trated and to describe the suitable protocol for WIC han -dling and maintenance aiming to optimise the analgesia at the same time as avoiding complications.ConclusionsBased on the findings of the present study, use of the WIC can be considered as part of the multimodal analgesic approach for postoperative pain management in cats. The placement of the WIC can be easily performed by the attending surgeon at the end of surgery in a large variety of surgical procedures with different LA administration protocols. The low incidence of major complications in this population of cats illustrates that the use of WICs is safe and encouraging.Acknowledgements We acknowledge the contribution of all the institutions that provided the data for this research

Answer 38

All dogs undergoing TL or TAL for treatment of PC inthis study survived the immediate postoperative periodexcept for 1 dog, which developed severe dyspnea leadingto euthanasia. In this dog, a French bulldog, the postop-erative recovery may have been complicated by concur-rent severe brachycephalic obstructive airway syndrome(BOAS) and whether the progression of pulmonary dis-ease played a significant role in the deterioration of thisdog's condition is uncertain. Previously reported mortal-ity for open lung lobectomy in dogs with pneumonia was20.3% in 1 study.7Perioperative mortality in the smallcohort of dogs described in this study compared favor-ably, with just 1 of 12 (8.3%) dogs failing to be dischargedfrom the hospital.7However, the cohort of dogs describedin this study is of differing breeds, differing diseaseseverity, and differing clinical presentation in comparisonwith those in other studies and so outcomes should notbe considered comparable. However, it does seem reason-able to suggest that TL and TAL may be considered anappropriate alternative to open lung lobectomy, primarilywhen performed by a surgeon experienced in thoraco-scopic surgical techniques. In 25.4% of dogs in a previousstudy, pneumonia did not resolve following open lunglobectomy.7Clinical resolution appears to have occurredin all patients within this case series that survived theimmediate perioperative period. Surgical lobectomy inthese patients seems to be warranted given the excellentlong-term outcomes in those that survived the initialperioperative period, with no dogs experiencing a recur-rence of clinical signs in a median follow-up time of24 months. The results of this study suggest that TL andTAL should be considered a safe treatment option fornon-neoplastic PC in select canine cases.Thoracoscopic surgical approaches have beenemployed increasingly in veterinary medicine and arewell established as an alternative minimally invasiveapproach for lung resection in the management of a sub-section of pulmonary disease in humans.18,19In thisstudy, a variety of underlying etiologies gave rise to non-neoplastic PC, which was medically unresponsive ordeemed unlikely to be responsive to medical manage-ment. Thoracoscopy allows exploration of the entireaffected hemithorax and may offer advantages over inter-costal thoracotomy, especially for treatment of migratingforeign bodies. Intercostal thoracotomies may limit tho-racic exploration of the region directly adjacent to theincision. In geographic areas where plant awn migrationinto the pleural space is commonly seen,20the ability toexplore the most caudal recesses of the thoracic cavity canbe advantageous as has been previously described.21Evenif a conversion is performed, there may be some benefit tobeing able to perform a more thorough evaluation of thethoracic cavity before converting. This may prove to bemore beneficial in patients in which advanced imaging isnot feasible. However, even in patients for whom com-puted tomography has been performed, the extent orseverity of adhesion formation in the thorax can easily beunderestimated.22Techniques do exist for improving theassessment of pleural adhesion formation on preoperativeCT, such as respiratory dynamic CT, but these techniqueswere not used in this study.23A variety of reasons have been documented for why aminimally invasive surgeon will elect for conversion. Themost common reasons are due to lack of adequate visual-ization to perform the procedure, inability to execute theprocedure or concern for the patient's safety. In thisstudy, the most common cause for conversion was thepresence of adhesions. Adhesions are most problematicDOWNEY ET AL . 915 1532950x, 2023, 6, in lung lobectomy during insertion of the cannulas, atwhich time hemorrhage or inadvertent penetration ofnontarget organs can occur.10Penetration of a nontargetorgan did not occur within this study population but ifadhesions are not able to be easily dissected then conver-sion to a TAL or open thoracotomy is usually required toproceed. The conversion was not necessary on an emer-gency basis or related to the failure of OLV in any dog inthis study. The conversion rate for the TL group was 44%(4/9) in this study, which is higher than the 9%-23%described in previous reports for TL performed for re-section of primary or metastatic lung tumors in dogs.15,17Conversion rates for VATS lobectomy for lung cancerwere reported to be 9.4% in human medicine.24In thisstudy there appeared to be a difference in the duration ofclinical signs between the dogs in which a conversionwas performed and those where the TL procedure wascompleted without conversion, although due to smallcase numbers this was not evaluated statistically. In caseswhere clinical signs have been present for a longer dura-tion of time preoperatively, it might make sense thatadhesion formation between lung lobes or between lunglobes and the thoracic wall might be more common,more extensive, or more fibrous in nature compared tocases where disease may have been present for a shortertime. Surgeons performing thoracoscopic lung lobectomyfor non-neoplastic PC should be prepared to convert anddiscuss the relatively high rate of conversions withowners preoperatively.The choice to perform either a TL or TAL approachwas largely case specific and was made according to thepersonal preference of the primary surgeon. The 3 caseswhere TAL was opted for at the outset were performed by1 surgeon at 1 center. There are advantages and disadvan-tages to both procedures as previously reported.8,17,19,25For TL, OLV is ideal to optimize the working space avail-able for intracorporeal organ manipulation and staplerplacement.26–28However, obtaining OLV can be techni-cally challenging to perform and does require additionaltraining to achieve favorable outcomes. One-lung ventila-tion was attempted in all TL dogs but was not pursued forthe TAL group. In the 3 dogs where OLV was unsuccess-fully performed, 2 of those dogs were brachycephalicbreeds (English bulldog, French bulldog). This may sug-gest that successfully achieving OLV in these breeds maybe more difficult due to bronchial conformation. It may bethat, in brachycephalic breeds, TAL might be favored overa TL approach just because it can be challenging toachieve OLV in brachycephalic breeds.Limitations of the study include the nature of retro-spective studies where medical records are not alwayscomplete. The sample size in this study was small butnon-neoplastic PC that fails medical management is anuncommon entity, especially in dogs that are large enoughto allow TL to be attempted. To maximize our case popula-tion data, 3 veterinary specialty institutions were includedin the study. Including the experience from varioushospitals created a more holistic view of a veterinary sur-geon's experience with a thoracoscopic approach forPC. However, short-term outcomes in the dogs in thisstudy may not be representative of the achievable resultsfor inexperienced thoracoscopic surgeons.In conclusion, TL or TAL is a feasible treatmentoption for non-neoplastic PC in select canine cases andresulted in favorable long-term outcomes. Enthusiasmfor the approach should be tempered by the knowledgethat conversion rates for thoracoscopic lung lobectomymay routinely be higher for the resection of consolidatedlung lobes than those observed for the resection of pri-mary pulmonary neoplasia.ACKNOWLEDGMENTSAuthor Contributions: Downey AC, DVM: Studydesign, acquisition of data, and manuscript preparation.Mayhew PD, BVM&S, DACVS: Conceived the study,study design, performed surgical procedures, acquisitionof data, and manuscript preparation. Massari F, DVM,DECVS: Study design, performed surgical procedures,and manuscript preparation. Van Goethem B, DVM,PhD, DECVS: Study design, performed surgical proce-dures, and manuscript preparation.CONFLICT OF INTERESTThe authors declare no conflict of interest related to thisreport.

Answer 39

Based on the literature search, this is the first time that a study evaluating changes in spontaneous physical activity variables using an accelerometer in a sample of dogs with CCLR was con -ducted. Based on the findings of this study, the hypothesis that an increase in physical activity would occur after surgical stabili -sation was rejected.In the study reported here, before surgery (T0), dogs pre -sented a predominantly sedentary behaviour (89%), a short time in light to moderate activity (10%) and an even shorter time in vigorous activity (1%). The CCLR itself may result in physical limitations such as pain, joint instability and the limb’s functional disability (Brown et al. 2010b , Schulz 2013 ), which could interfere in the daily activities of dogs, with a consequent decrease in spontaneous physical activity. It was hypothesised that after surgery to correct CCLR, there would be an increase in spontaneous physical activity, represented either by a decrease in sedentary activity or by an increase in light to moderate and/or vigorous activity. However, despite a gradual and complete recovery up to 6 months, as observed during periodic postoperative evaluations and also based on results of questionnaires completed by the owners, no signifi -cant change was noticed in the data obtained with the accel -erometer. Physical activity in the postoperative period was not significantly improved as compared with values before surgery at any time point. Since the study did not include a control group, it is unclear whether the lack of change was due to the fact that activity varied too widely to detect changes (and therefore the study was underpowered), whether the dogs’ activity was normal all along, or whether the dogs’ activity was decreased and did not increase despite surgery.In the present study, the same lateral fabellar suture technique was used and the same surgeon performed all CCLR repair sur -geries in order to eliminate the influence of these variables on the results. Extracapsular stabilisation has been described as the most common stabilisation method to correct CCLR in dogs weigh -ing less than 15 kg (Comerford et al. 2013 ). According to Casale & McCarthy ( 2009 ), increased bodyweight was associated with a greater risk of postoperative complications for this technique. Therefore, it was decided to include only small to medium- sized dogs in this study, which resulted in a mean weight of 12.3±5.1 kg. Despite the choice of the lateral fabellar suture, it does not pre -clude future studies with accelerometry from being carried out with other surgical techniques such as corrective osteotomies. Recent studies have shown excellent results after tibial plateau Table 2. Mean±sd of lameness score, thigh circumference of affected and non- affected limbs, pain score and quality of life score for 17 dogs with cranial cruciate ligament rupture that underwent surgical correction. T0 is 7 days before the surgery whereas T1, T3 and T6 are 1, 3 and 6 months after surgery, respectivelyParametersTimeT0 T1 T3 T6Lameness score 1.94±0.89 1.17±0.72 † 0.05±0.24 † 0†Thigh circumference (cm)Affected limb 26.3±5.1 ‡ 25.6±4.5 26.8±5.7 § 26.9±4.9 §Non- affected limb 29.1±5.6 28.7±5.5 28.5±5.7 28.3±5.6Pain score 2.17±0.39 1.11±0.33 † 1.23±0.56 † 1.05±0.24 †Quality of life 1.47±0.62 2.52±1.00 † 3.41±0.61 †§ 3.52±0.62 †§†Significant difference compared to T0 (P<0.05)‡Significant difference in comparison with the non- affected limb at that timepoint (P<0.05)§Significant difference compared to T1 (P<0.05) 17485827, 2023, 10, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jsap.13645 by Vetagro Sup Aef, Wiley Online Library on [19/10/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicensePhysical activity in dogs with CCLRJournal of Small Animal Practice • Vol 64 • October 2023 • © 2023 British Small Animal Veterinary Association. 623 levelling osteotomy (TPLO) in small breed dogs (Amimoto et al. 2020 ). The use of this technique could generate greater activ -ity variation, being a possibility for future studies. It is possible that our results reflect the inferiority of the lateral fabellar suture when compared to the TPLO (Gordon- Evans et al. 2013 ). TPLO in dogs weighing less than 15 kg has been reported to have excel -lent outcomes (Marin et al. 2021 ) and shown to have better out -comes than extracapsular suture (Berger et al. 2015 ).Dogs in the present study presented mild stifle pain at T0 (mean score: 2.17±0.39). The lack of intense pain might be explained by the prolonged mean injury time of 41 days, which may have resulted in a reduction of the inflammatory process, with thickening of the periarticular tissues and a decrease in stifle pain (Schulz 2013 ). Therefore, it can be suggested that one of the main reasons for the unchanged activity is that the stifle pain before surgery was not of sufficient intensity to interfere with spontaneous physical activity. Muller et al. (2018 ) assessed, using accelerometry, the recovery of dogs from joint pain after treat -ment with non- steroidal anti- inflammatory drugs. The authors reported that physical activity increased significantly more with treatment in dogs that, at first assessment, had more severe pain compared to those that had less severe pain.Stifle pain scores and lameness scores decreased over time in the dogs of the present investigation, which is similar to what occurred in previous studies after surgical repair of CCLR (Stein & Schmoekel 2008 , MacDonald et al. 2013 , Berger et al. 2015 ). The lameness score is often used to evaluate limb functional recovery after CCLR correction (Stein & Schmoekel 2008 , Moeller et al. 2010 , Gordon- Evans et al. 2013 , MacDonald et al. 2013 , Berger et al. 2015 ). Some authors highlighted that the return to normal (or full) function is the best orthopaedic surgery success indicator (Hoelzler et al. 2004 ). In the present study, despite lameness scores decreased over time, no increase in physical activity was observed. Unilateral injury might not be so decisive to limit or change spontaneous physical activity, as dogs are able to maintain their daily activities using three limbs (Galindo- Zamora et al. 2016 ).It has been reported that limb disuse after ligament injury (Moeller et al. 2010 ) and variations in the time from the injury until subsequent surgical stabilisation result in muscle atrophy (Moeller et al. 2010 , MacDonald et al. 2013 ). In the present study, muscle atrophy was evidenced by a decrease in thigh circumfer -ence of the affected limb compared to the unaffected limb at T0. The mean reduction of 9% in thigh circumference was greater than the reduction reported in previous studies, which ranged from 1.5 to 4% (Moeller et al. 2010 ; MacDonald et al. 2013 ). This major reduction of thigh circumference at T0, associated with restrictions and limited limb use in the first 3 weeks of the postoperative period, contributed to a delay muscle mass gain. As a result, the thigh circumference of the affected limb measured at T1, T3 and T6 did not change compared to T0.Although postoperative thigh circumference of the affected limb did not differ from T0, a significant increase was detected between T3 and T6 compared to T1. During this period, the dogs showed the greatest limb functional recovery and their owners reported greater return to physical activity. These find -ings agree with Marsolais et al. (2002 ) who stated that a gradual return to physical activity and limb function recovery trigger slow muscle mass recovery. However, results of the present study suggest that limb function return and restarting activities do not necessarily imply an increase in activity frequency as no increase in physical activity levels or reduction in sedentary behaviour were found. This may be one of the factors that contributed to the delay in muscle mass gain. If an increase in movement and physical activity had occurred, consequently increasing the limb’s use, the muscle recovery process might have been accelerated.In previous studies, the thigh circumference of dogs returned to normal values only at 1 year of follow- up (Gordon- Evans et al. 2013 , MacDonald et al. 2013 ), or less than 1 year consider -ing dogs that underwent physiotherapy. Therefore, there is a trend that, over time, the muscle mass gain curve is maintained and thigh circumference returns to normal pre- injury levels (Gordon- Evans et al. 2013 ). Despite physiotherapy benefits, dogs in the present study were not subjected to rehabilitation protocols and their owners were not advised to increase the physical activities because our objective was to assess spontaneous physical activity.In a previous study (Morrison et al. 2014a ), a relationship between age of dogs and physical activity was identified, with aged dogs presenting an increase in sedentary lifestyle and a decrease in high- intensity activities. It may be suggested that, because dogs of the present study were of considerably advanced age (7.5±2.6 years), they already had a sedentary lifestyle before the CCLR, and the limb clinical and functional recovery did not result in changes in the already established lifestyle.Another point to take into consideration is that dogs can be highly influenced by their owners’ habits (Morrison et al. Table 3. Mean±sd and percentage values of physical activity measured using the accelerometer in 17 dogs with cranial cruciate ligament rupture that underwent surgical correction. T0 is 7 days before the surgery whereas T1, T3 and T6 are 1, 3 and 6 months after surgery, respectivelyActivity T0 T1 T3 T6 P valueSedentary, (minutes/day) † 1288±41, 89.4% 1279±41, 88.9% 1276±38, 88.6% 1288±33, 89.4% 0.73Light to moderate, (minutes/day) ‡ 138±39, 9.6% 146±39, 10.1% 150±35, 10.4% 139±30, 9.7% 0.70Vigorous, (minutes/day) § 14±6, 1% 15±7, 1% 14±6, 1% 13±7, 0.9% 0.78Total (mean cpm) 396±107 412±102 410±100 387±94 0.79Minutes/day considering the use for 24 hours/day†<1351 accelerometer cpm‡1352 to 5695 accelerometer cpm§> 5696 accelerometer cpm 17485827, 2023, 10, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jsap.13645 by Vetagro Sup Aef, Wiley Online Library on [19/10/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseL. A. H. Schuster et al.Journal of Small Animal Practice • Vol 64 • October 2023 • © 2023 British Small Animal Veterinary Association. 6242014b ), thus influencing the amount or type of physical activ -ity performed. Therefore, the interpretation of the data from the accelerometer should be carefully carried out because even with the recovery of dogs observed in our study, the increase in activity can be limited by factors related to owners.Data from questionnaires related to the quality of life indicated that the owners noticed an improvement in their dogs after sur -gery. The improvement was gradual and significant and at the end of 6 months, the dogs had their quality of life rated as very good or excellent in 94% of cases. This finding is consistent with results of clinical evaluations that indicated recovery after this surgical procedure (Gordon- Evans et al. 2013 , Berger et al. 2015 ).According to the questionnaire responses concerning physical activity, the vast majority of owners reported a decrease (94%) in the preoperative period, followed by a partial return in activ -ity during the first month, and at 6 months, 100% of dogs had returned to the same level of physical activity as before the rup -ture. Although the owners’ opinion is a subjective variable, the questionnaires have been considered a valuable tool because owners spend most of their time with their pets (Conzemius & Evans 2018 ). However, owners may underestimate or over -estimate activity levels due to difficulties in remembering and reporting this type of information accurately (Durante & Ain -sworth 1996 ). The use of the accelerometer in this study pro -vided an objective measure of physical activity in an attempt to minimise the limitations of the questionnaires. However, the increase in physical activity reported by the owners was not accompanied by changes in the data measured by the acceler -ometer. As a result, with accelerometry providing more objective data to measure outcome, it is possible that our data collected from owners were inconsistent.The results of the questionnaire about physical activity suggest that owners may have overestimated the physical activity decrease at T0 due to the fact that the dogs limped or had difficulty in per -forming certain routine functions. The return to physical activity reported by the owners in the postoperative period appears to be influenced by the decrease in lameness and improvement in limb function. However, the decrease in lameness did not reflect an increase in spontaneous physical activity. These results are inter -preted as indicating that neither the preoperative limitations nor the recovery of the dogs in the postoperative period resulted in changes in physical activity levels. These findings are similar to a previous study carried out in humans (Kuenze et al. 2019 ). In that study, the authors found no significant relationship between physical activity objectively measured with an accelerometer (moderate to vigorous activity) and the activity self- reported by patients via questionnaires. Similarly, there was no relationship between moderate to vigorous physical activity and stifle exten -sion strength tests.The results of this study, as well as those reported by Kue -nze et al. (2019 ) demonstrate the complexity of the relationship between physical activity and measures of function return. It is suggested that because of our study’s population characteristics, physical activity may be linked and conditioned to a daily life habit that would require major events to change. The greatest time that the dogs spent in sedentary activity and the shortest time spent performing any level of physical activity could be an alert. A gradual increase in physical activity can be assessed in terms of health benefits, including chronic disease prevention and muscle mass maintenance (German 2010 ).This study aimed to understand how changes in physical activity variables occur over time by observing CCLR recovery phases, focusing on the hypothesis that the dogs’ recovery would result in increased activity. Consequently, a control group was not included, which is similar to a previous study conducted by Morrison et al. (2014b ). However, with the absence of a control group, the small sample size can be considered a limitation. It may be interesting, in future studies, to compare these data with results of a control group of dogs that did not undergo surgery because their owners refused the procedure or with a group of animals submitted to other surgical techniques, e.g. medium to large breed dogs submitted to TPLO. Another limitation of our study was that it did not use animals with acute pain and recent CCLR, thus standardising the population in terms of time of injury. Although the subjective methods used to evaluate the dogs of the present study have already been used frequently (Stein & Schmoekel 2008 , Moeller et al. 2010 , Gordon- Evans et al. 2013 , MacDonald et al. 2013 , Berger et al. 2015 ), the inclusion of an objective method for orthopaedic assessment of patients, such as a force platform, would provide additional information, and the lack of such method can also be considered a limitation of the present study. Despite these limitations, our study showed that it is possible to use an accelerometer to collect objective physical activity data from dogs recovering from CCLR.In conclusion, despite the clinical recovery in dogs being observed until the sixth month after correction of CCLR with extracapsular suture, there was no objective change in the physi -cal activity levels’ measurement using an accelerometer consider -ing the same period.AcknowledgementsThis study was financed in part by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Coorde -nação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) – Finance Code 001.Author contributionsLucas Antonio Heinen Schuster: Conceptualization (lead); data curation (lead); formal analysis (lead); investigation (lead); meth -odology (lead); project administration (lead); resources (equal); software (equal); supervision (equal); validation (equal); visual -ization (equal); writing – original draft (lead); writing – review and editing (lead). Anderson Luiz de Carvalho: Conceptual -ization (equal); data curation (equal); formal analysis (equal); investigation (equal); methodology (equal); software (equal); validation (equal); visualization (equal); writing – original draft (equal); writing – review and editing (equal). Eduardo Almeida Ruivo dos Santos: Data curation (equal); investigation (equal); methodology (equal); software (equal); validation (equal); visual -ization (equal); writing – original draft (equal); writing – review and editing (equal). Mariana Pires de Oliveira: Conceptual -ization (equal); formal analysis (equal); investigation (equal); 17485827, 2023, 10, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jsap.13645 by Vetagro Sup Aef, Wiley Online Library on [19/10/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicensePhysical activity in dogs with CCLRJournal of Small Animal Practice • Vol 64 • October 2023 • © 2023 British Small Animal Veterinary Association. 625 methodology (equal); resources (equal); visualization (equal); writing – original draft (equal); writing – review and editing (equal). Cesar Augusto Camacho - Rozo: Data curation (equal); formal analysis (equal); methodology (equal); software (equal); validation (equal). Eduardo Raposo Monteiro: Conceptual -ization (equal); data curation (equal); formal analysis (equal); methodology (equal); project administration (equal); visualiza -tion (equal); writing – original draft (equal); writing – review and editing (equal). Márcio Poletto Ferreira: Conceptualiza -tion (equal); data curation (equal); formal analysis (equal); methodology (equal); project administration (equal); visualiza -tion (equal); writing – original draft (equal); writing – review and editing (equal). Marcelo Meller Alievi: Conceptualization (lead); data curation (equal); formal analysis (equal); funding acqui -sition (lead); investigation (equal); methodology (equal); project administration (lead); resources (equal); software (equal); super -vision (lead); validation (equal); visualization (equal); writing – original draft (equal); writing – review and editing (equal).Conflict of interestNone of the authors of this article has a financial or personal relationship with other people or organisations that could inap -propriately influence or bias the content of the paper.

Answer 40

This study demonstrated that ﬂuoroscopically guided per-cutaneous application of double HCS was safe in a unilateralsacroiliac luxation model in small dogs without violation ofthe vertebral canal and ventral sacral foramen. Moreover,resistance to rotational force applied on the ﬁxation of thesacroiliac joint repaired with double 2.3-mm HCS estimatedby maximum failure load was signi ﬁcantly higher than thatof a single 3.5-mm CS. Therefore, our hypotheses were bothaccepted.A surgical anatomy study of the canine sacrum for lagscrew ﬁxation reported that the area for correct screwplacement on the lateral surface of the sacral wing is slightlylarger than 1 cm2even in large-breed dogs.2In a study thatplaced two screws within the sacral body, the authorsreported that approximately 20% of screws were not suc-cessfully placed in the target area.21The ventral limit of thespinal canal overlaps with the dorsal 45% of the sacral wingheight, and the ﬁrst ventral sacral foramen limits the safecorridor to the caudal 20% of the sacral wing length.4Owingto this anatomical structure, the second 2.3-mm HCS has thepotential to damage the spinal canal or the ﬁrst sacralTable 3 Objective measurements of mechanical test to rotational force on each ﬁxationDouble 2.3-mm HCS group Single 3.5-mm CS group p-valueMaximum failure load (kgf) 3.91 /C62.51a1.14/C60.58a0.002Moment arm (cm) 3.62 /C60.36 3.70 /C60.41 0.631Maximum rotational force at failure (kgf-cm) 14.30 /C69.50a4.16/C61.96a0.002Abbreviations: CS, cortical screw; HCS, headless cannulated self-compression screw.aStatistically signi ﬁcant differences.Fig. 5 Failure modes of test groups. Rotational failure of hemipelvis is observed in all hemipelvises of both experimental groups ( AandB,redarrows ). (A) In hemipelvises using single 3.5-mm CS lag screws, loss of ﬁxation at the level of screw head without implant pullout or breakage isobserved. ( B) In the 2.3-mm HCS group, the heads of the screws rotated together while trailing threads are engaged in the ilium. ( C)C o r t i c a lbone fracture of sacral dorsal lamina ( arrow )a n d( D) vertebral body ventral to the screws ( asterisk ), and ( E,F) breakage of screw heads(arrowheads ) are observed in the 2.3-mm HCS group. In the other samples of the double 2.3-mm HCS group, the screws lost their stability withinthe cancellous bone of the sacral body. CS, cortical screw ;H C S ,h e a d l e s sc a n n u l a t e ds e l f - c o m p r e s s i o ns c r e w .Veterinary and Comparative Orthopaedics and Tra umatology Vol. 37 No. 1/2024 © 2023. The Author(s).Comparison of Double 2.3-mm HCS and Single 3.5-mm CS in a Canine Model Kang et al. 19foramen. However, despite the narrow anatomy of the safecorridor and caudal position of the secondary screw in thisstudy, double 2.3-mm HCS were inserted safely using acannulated screw system without iatrogenic damage tothe adjacent structure.The angles between the ﬁrst and second 2.3-mm HCSestimated by CCA and DVA were almost parallel as intended.Although it was described that two screws inserted diver-gent from each other show better mechanical properties inrotational and axial loading,22–24insertion of a double screwdivergently in this study was impossible considering theanatomical aspects on preimplantation CT. Mechanically,when two lag screws are placed parallelly, the second screwcan provide an additional compression force as well as limitthe rotational force.24Additionally, CCA and DVA in ourstudy show more variable results than the target pointcompared with previous results reported by Déjardin andcolleagues.18This result could be a technical issue becausewe adjusted the aiming device by hand rather than a customﬁxture. As another concern, we did not apply a metal artifactreduction protocol to analyze the CT data, which may haveaffected these results due to artifact errors.Two-point ﬁxation with double smaller screws showedhigher maximum failure load to rotational, bending, andshear forces than a single larger screw in the static mechani-cal test of conventional lag screws in the canine sacroiliacluxation model.6Moreover, the second screw can act as arotational force neutralizer, and superior clinical outcomeshave been obtained in human scaphoid fractures when usingdouble HCS.25However, there have been no such studies insmall dog sacroiliac luxation models with small HCS. Al-though we used a titanium HCS, which has lower stiffnessand a higher occurrence of elastic deformation than stainlesssteel implants, double 2.3-mm HCS showed approximately3.4 times greater resistance to the rotational force thansingle stainless steel 3.5-mm CS based on our results.26Therefore, the ﬁndings of this study are consistent withthose of previous reports on the bene ﬁts of an additionalantirotation screw. However, we did not conduct cyclicloading or other translational motion tests to evaluate theeffect of repeated loading on the ﬁxation constructs, whichcould further mimic clinical situations regarding fatiguefailure of ﬁxation constructs or implants. Further bio-mechanical studies are necessary to ensure the safety ofapplying double 2.3-mm HCS in clinical cases.The failure modes between the two ﬁxation systems weremarkedly different, which may have resulted from the differ-ent principles of compression and the presence of the secondscrew acting as an antirotational stabilizer. In hemipelvisesrepaired using 3.5-mm CS in the lag fashion, the compressionforce that stabilized theconstructs was lost between thescrewhead against the surface of the ilium. Meanwhile, in ﬁxationsusing double 2.3-mm HCS, loss of stability occurred mainly atthe sacrum, while the trailing thread engaged in the ilium.Moreover, breakage of the screw head was observed. Thisdifference may have occurred becausethesecond HCS allowedthe stress to be distributed compared with the single screw.25In addition, we did not apply the 3.5-mm CS with a washer toTable 4 Failure modes of mechanical test and Fisher ’s exact test resultsSacral laminafractureVentral sacralbody fractureSacrum cancellousdestructionScrew headbreakageCompression failureat headTotal p-valueDouble 2.3-mm HCS group ( n¼11) 2 (18.2%) 1 (9.1%) 6 (54.5%) 2 (18.2%) 0 (0.0%) 11 (100%) <0.001Single 3.5-mm CS group ( n¼11) 0 (0.0%) 0 (0.0%) 0 (0.0%) 0 (0.0%) 11 (100%) 11 (100%)Abbreviations: CS, cortical screw; HCS, headless cannulated self-compression screw.Veterinary and Comparative Orthopaedics and Traumatology Vol. 37 No. 1/2024 © 2023. The Author(s).Comparison of Double 2.3-mm HCS and Single 3.5-mm CS in a Canine Model Kang et al. 20reduce thevariables that canaffect theexperimental results,asthe application of a washer depends on the surgeon ’sp r e f e r -ence and patients.2,16,19,21,27,28However, the washer allowsmore compression to be generated by distributing the com-pressive force over a large area.29Several studies have reportedthat thecompression that the trailing threads ofa HCS achievesis far inferior to that of an Arbeitsgemeinschaft für Osteosyn-thesefragen (AO) screw with a washer.29–31Therefore, if the3.5-mm CSwere used in conjunction with a washer, the failureloads and modes would be different. Another clinical dilemmaarising from our ﬁnding is whether treating a sacroiliacluxationthrough double HCSisuniversally indicated.Althoughhemipelvises repaired with double 2.3-mm HCS showedhigher maximum failure load compared with the 3.5-mm CSgroup, the result could be more debilitating to a clinical patientif complications such as sacral body fracture or failure oc-curred. Therefore, further clinical studies on using double 2.3-mm HCS for sacroiliac luxation are necessary to provideinformation on the risk regarding the application of doubleHCS and ensure clinical safety.One of the interesting ﬁndings in our study was that thedifference in mean failure load between the left and right sidesin the single 3.5-mm CS group was close to being signi ﬁcantlydifferent ( p¼0.052). We used the conventional right-handedCS, which tightened the sacroiliac joint in the clockwisedirection. However, when a standing ground reaction forcewas applied to the left side, the torsional force would haveacted in the anticlockwise direction to the sacroiliac joint.Therefore, it may have contributed to showing weaker resultscompared with the opposite side in maintaining torque.32Inaddition, the statistical signi ﬁcance may have been affectedbecause we did not control for the variables such as the lengthand torque of the screws. Further investigations on the failureload according to the screw application sides and threaddirections in the clinical setting are needed.Several limitations of this study should be considered whentranslating the results into clinical situations. First, because of itsex vivo nature and our testing methodology, our study does notmimic actual weight-bearing conditions, and soft-tissue supportwas absent.33–35In clinical cases, ﬁbrous tissue formation aroundthe sacroiliac joint followed by initial ﬁxation may provideadditional resistancetothe rotational force. Furthermore, inducedluxation of the sacroiliac joint model did not have changes,including muscle contracture and edema of the surroundingsoft tissue or other pelvic injuries. Therefore, dif ﬁculties in thereduction and safe placement of double HCS may differ from theclinical cases. However, our experimental ﬁndings highlight theusefulness of augmentation with a second screw for sacroiliacluxation with regard to acute failure load in a clinical setting.Second, since only one surgeon performed the procedures, theresults related to experience may vary. Finally, we did not use ametal artifact reduction protocol during the CT scan. Therefore,there could be artifact errors in the measurements of the meani n s e r t i o na n g l e sa n de n t r yp o i n t so ft h es c r e w s .The feasibility of safe placement of double 2.3-mm HCS in acadaveric small dog sacroiliac luxation model was con ﬁrmedin this study. Further, our results suggest that constructsusing double 2.3-mm HCS are mechanically superior to theresistance of the rotational force than single 3.5-mm CSplaced in the lag fashion. Although this was an experimentalcadaveric study, based on our results, the use of smallerdouble HSC may be bene ﬁcial as an alternative to the conven-tional single lag screw for stabilization of sacroiliac luxationin small dogs. Further investigations on the clinical applica-tion of 2.3-mm HCS are necessary.

Answer 41

We found that perioperative infiltration of LB in GIFBremoval surgery was associated with a decreased dura-tion and rate of fentanyl use postoperatively as well asthe duration of ICU and duration of stay in our hospital.However, more incisional complications were seen inthis group of dogs after use of LB. A demographic differ-ence was found: LB was used in larger dogs. However,there was overlap between the two groups. Given thatLB vials in our institution are single use in a practicalsense due to the short time allowed for use once opened,there might have been a financial and resource-drivendecision-making process away from use of LB insmaller dogs.Dogs receiving LB in this study had their fentanyltapered faster, and were able to leave the hospitalsooner than those that did not. The decrease in opioidrequirement, both in dose and duration, aligns withearlier publications,3–5but not with recent prospectivesoft tissue studies presented in abstract formats.6,7Thedoses of opioids administered after cranial cruciate lig-ament surgery was lower for dogs receiving LB thanbupivacaine, and less dogs receiving LB needed rescueanalgesia (as determined based on pain scores) com-pared with bupivacaine (3/14 dogs that received LBcompared with 10/14 dogs that received bupivacaine),3or placebo (15/24 dogs that received LB vs. 20/22 dogsthat received placebo).4Fewer dogs receiving a TAPblock after elective ovariohysterectomy (either with LBor a mix with bupivacaine/d exmedetomidine) neededrescue analgesia than dogs that received no block (4/9dogs that received a LB TAP block and 3/9 dogs thatreceived a bupivacaine/med etomidine TAP block com-pared with 7/8 dogs that received no block), and thedogs that received the block had lower pain scores.5However, dogs from all groups needed rescue analge-sia. Two prospective soft-tissue surgery focused studieson the analgesic effect of LB were recently presented atthe 2022 American Colleg eo fV e t e r i n a r yS u r g e o n s(ACVS) surgery summit6,7and incisional complicationswere reported in a third.12No control group wasincluded in the larger prospective laparotomy study,12whereas the other two studies had lower numbers ofdogs included,6,7and one had a variety of incisions,with any incision of 1 cm or more being the inclusioncriterion.7Our study is a retrospective study, which has inherentobservational limitations. Clinicians were not necessarilyblinded to which case received LB during postoperativeTABLE 2 Postoperative complications for the dogs that received LB and those that did not.Postoperative complicationsLB (n=65) no LB ( n=140)p Dogs (%) Dogs (%)Complications noted 15 (23.1%) 22 (15.7%) .200Regurgitation 4 (6.2%) 5 (3.6%) .469Surgery site complications 7 (10.7%) 4 (2.9%) .03995% CI =4.4–21.0% 95% CI =0.8–7.2%Revision surgery 3 (4.6%) 1 (0.7%) n/aNumber LocationDehiscence 4 SC, SC, Abd, multi 3 n/aSeroma 1 Abd 0 n/aAbscess needing surgery 1 Multi 0 n/aInfection (discharge from site) 1 Muscle/SC 1 n/aNote : General complications (regurgitation) and surgery site complications are stated with the latter subdivided. No statistical analysis performed d ue to smallnumbers per (sub)groups.Abbreviations: Abd, in abdominal wall before abdominal wall closure; LB, liposomal bupivacaine; multi, in muscle, subcutaneous tissue and skin; mu scle, inrectus abdominus; n/a, not applicable; SC, subcutaneous tissues.RAHN ET AL . 1029 1532950x, 2023, 7, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.13976 by Vetagro Sup Aef, Wiley Online Library on [19/10/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensecare, which might lead to bias in attempting to taper fen-tanyl earlier. However, postoperative care was not neces-sarily performed by the operating surgeon due to thescheduling structure of the on-call surgery clinicians,with postoperative care provided by the soft-tissue ser-vice. Use of LB was not specifically noted on ICU treat-ment sheets and nursing staff would not have beenalerted to its use during postoperative pain scoring andcomfort assessment. An objective measurement tool(as was used by Hixon et al.)6or having a separate,blinded, observer assess and record postoperative painscores would have removed the potential for bias but wasnot performed due to the retrospective nature of the datacollection.Overall, a SSC rate of 10.7% (7/65) after use of LB and2.9% (4/140) without LB were seen. Of the seven of thesedogs receiving LB, two had a SSI and four had a dehis-cence compared to one SSI and three dehisced incisionsin dogs not receiving LB during the same time period.Four dogs ultimately needed revision surgery (three thatreceived LB, and one that did not). Both the overall SSCand SSI rates fall within prior reported complicationrates, dogs that were administered LB had more compli-cations than those that did not. Surgical site infectionrates after limb amputations were reported as 13/31 withLB, and 63/217 without LB; however, other factors (suchas use of a vessel sealing device and the presence of infec-tion and/or trauma) contributed to the SSI in this study.14Local macroscopic complications, such as redness andswelling, have been described for a different formulationof LB that was administered at higher doses; however,the authors attributed these signs to injection trauma.8Asimilar finding of redness in the immediate postoperativewas reported in the majority of dogs receiving LB in arecent prospective study,12and the high number wasattributed to the strict inclusion criteria for postoperativecomplications. A total of 80 dogs still had incisional com-plications at their 2 week recheck. However, given thelack of a control group with the same injection protocolwith a different solution, no firm conclusions can bedrawn regarding whether the high incidence was relatedto the injections, the use of LB, or the strict reporting cri-teria.12Campoy et al. administered the TAP block priorto the start of surgery, and although dogs were followedfor 96 h for analgesia and comfort, the authors did notcomment on any incisional complications.5Injecting LBwithin a muscle and within a closed compartment iscomparable to reports of LB use in human open abdomi-nal surgeries, where LB was administered as a TAPblock, either under visualization or ultrasound guidanceby the surgeons along the costal arch,15from outside theabdomen or from within the abdominal cavity.16Incisionfollow ups and potential complications were not recordedor reported in either study. However, the lack of compli-cations reported for studies in which direct injection ofLB into muscle enclosed within a fascial compartment(such as a TAP block or similar) warrants further investi-gation and follow up to see if extrapolation for safe use ofLB in contaminated abdominal surgery can be made.Limitations inherent to the retrospective nature ofthis study other than potential bias in pain assessmentalso exist: potential inclusion bias, data collection fromrecords, and method of injection. It is possible that theperioperative decision to use LB was weighted towardsdogs expected to need less postoperative analgesia orbe able to go home within the working time frame of72 h. More dogs that underwent gastrotomy surgeryreceived LB than those that did not, surgery type wasnot different between groups ( p=.111), while the % ofdogs undergoing enterotomy was 35% for both groups.A personal bias towards use of LB versus not using LBcould also be present, as evidenced when we looked atthe distribution of dogs between supervising surgeonsand the proportion of dogs under their care thatreceived LB versus those that did not. We tried to useobjective data points such as rate of fentanyl but ulti-mately relied on accurate notation of times, rates, andfindings in medical records. The method of infiltrationwas not standardized, and could lead to differences inefficacy and outcome. Eleven different ways of admin-istering LB were used, where ideally only one wouldbe used. In addition, these data were recovered fromsurgery reports, and were not noted in some. Due tothe nature of the data retrieved and the break down insmall sample size, we did not attempt to introducelocation of infiltration as a variable in our statisticalanalysis. Optimization of administration site could bebeneficial for future use in abdominal surgery. Interest-ingly, the TAP block protocol described in the twohuman papers on LB in open abdominal surgery dif-fered in methodology and site of administration aswell.15,16Like the tissue site of administration, infor-mation on dilution of LB prior to administration wasnot recorded, but standard hospital practice is not todilute LB. Increase in ml/cm incision infused was onevariable associated with decreased incisional complica-tions in a recent abstract.12Other patient variables,such as metabolic variation between larger and smallerdogs as well as body condition scores could haveplayed a role, and could have affected the outcome.The use of LB did decrease the time that dogsreceived fentanyl and shortened their hospital stay butthe increase in surgical site complications did raise a con-cern. We chose to include GI surgery specifically andfocus on a specific group of dogs and procedures thatmight have a higher risk of intraoperative contamination.1030 RAHN ET AL . 1532950x, 2023, 7, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.13976 by Vetagro Sup Aef, Wiley Online Library on [19/10/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseWe have since added lavage of the subcutaneous tissueswith fresh saline, post abdominal closure, prior to injec-tion of LB, as a precautionary step, to minimize the riskfor local contamination.5|CONCLUSIONLiposomal bupivacaine was associated with adecreased use and amount of postoperative opioidsafter abdominal surgery in the dogs in this study, andshortened hospitalization stay postoperatively. How-ever, a larger number of SSCs occurred in dogs thatreceived LB after GIFB removal surgery than in dogsthat did not.ACKNOWLEDGMENTSAuthor Contributions: Rahn AP, DVM: Data collec-tion; data analysis; manuscript writing; approval of thefinal version of the manuscript. Moore GE, DVM, PhD,DACVIM, DACVPM: Data analysis; approval of final ver-sion of the manuscript. Risselada M, DVM, PhD, DECVS,DACVS-SA: Study concept; oversight of the study; datacollection; manuscript writing; approval of the final ver-sion of the manuscript.FUNDING INFORMATIONNo grants or financial support were received to fund thisresearch.CONFLICT OF INTEREST STATEMENTThe authors declare no conflict of interest.ORCIDMarije Risselada https://orcid.org/0000-0003-1990-4280

Answer 42

This study demonstrated mechanical superiority of theAdhFix adjunct fixation over fixation with a Kirschnerwire, when used in combination with a transcondylarscrew in a lateral humeral condylar fracture model, simi-lar to the findings of Coggeshall et al.10Coggeshall et al.demonstrated that adjunctive fixation with an epicondy-lar plate was superior to that of a Kirschner wire.10Inaddition, no significant difference was demonstratedin yield load between plate fixation and AdhFix fixation.There was no significant difference in stiffnessbetween the paired groups, indicating the high initialload bearing ability of the transcondylar screw. In addi-tion to this, the maximum load values of paired con-structs AdhFix group or pin group were not differentfrom each other, suggesting the transcondylar screw isthe main load-bearing implant at high loads.Previous models investigating this fracture type haveshown plate fixation to be mechanically superior toKirschner wires for the adjunct fixation of the epicondylein lateral humeral condylar fracture models.10These andother reports investigating fixation in this region wereperformed using a fracture gap model.15–17In the clinicalsetting, true fracture gaps in lateral condylar fractures areuncommon and therefore a model that more closely mir-rored the clinical setting was used for this study. Theposition of the transcondylar osteotomy and epicondylarosteotomy were standardized for all models and osteo-tomies were performed with a sagittal saw under laserline guidance to minimize variation between groups.The pin group yielded at significantly lower forcethan the AdhFix group. K-wires are known to provideless rigidity to fractures than plates and AdhFix in otherfracture models. Hutchinson et al.12reported thatK-wires provide less rigid fixations in fully reduced trans-verse fractures in porcine metacarpals than AdhFix ormetal plates. Whilst the use of a nongap model couldpotentially benefit weaker adjunct fixation, such asKirschner wires, due to a degree of load sharing at theepicondylar ridge, our results indicate that this did notinterfere with the ability to identify superiority of theAdhFix group to the pin group.The lack of difference between the AdhFix and plategroups would imply that plate fixation would have beenmore robust than Kirschner wire fixation in our modelhad they been directly compared; however, this wasbeyond the scope of this study. Whilst cadaver modelswill never perfectly match the fractures encountered inthe clinical setting, creation of a standardized model thatmore closely mimics clinical fractures is important whenevaluating implant mechanics.There are multiple potential benefits to the use ofcomposites for fracture fixation of the canine humeralcondyle. Subjectively, the lateral aspect of the distalcanine humerus is a difficult region to contour platesto.18Nonlocking plates require accurate contouring togenerate bone-plate friction and stable fixation. Lockingplates mitigate some of the issues of requiring perfectcontouring but many locking plate systems are fixedangle or only allow 10 degrees of angulation betweenplate and screw trajectory, which can introduce problemswhen they are used in a periarticular position such as thehumeral condyle. This recently reported canine humeralanatomical plating system may provide a good option forthe repair of these fractures; however, it requires addi-tional inventory as well as not being applicable to smallerbreeds, such as French bulldogs, which are also com-monly affected by humeral condylar fractures.18,19Use ofa composite system allows for reduced inventory as wellas being adaptable to any size of patient, due to the cus-tom nature of the fixation.An additional major clinical benefit to the use of com-posites rather than commercially available plates is theability to place screws in any position to maximizethe available bone stock and account for individual varia-tion between bones in areas with challenging anatomyfor contouring. In this study, the spacing between screwsin the AdhFix group was decided using the same plateprofile as the Plate group. This was for research purposesonly, to standardize both the spread of the screws andnot add an additional variable that could inadvertentlybenefit the AdhFix group due to the ability to maximizeavailable bone stock. In the clinical case, use of AdhFixwould allow screws to be placed in the largest bone stock,whilst avoiding the joint surface and the supratrochlearforamen. This would be a major advantage over the cur-rent, commercially available fixed angle locking platesystems.This technology allows the replacement of the major-ity of the metallic implants with hydroxyapatite basedcomposites, which may also have benefits regarding painexperienced by patients when exposed to cold tempera-tures, reduced stress-shielding due to the modulus ofelasticity of the composites being closer to that of bone,as well as lack of soft tissue adherence.12,14Further stud-ies in companion animals would be required to seewhether these benefits are also seen in dogs and cats.Adhfix has been previously evaluated with regards tomechanics on porcine metacarpal bones with fullyreduced transverse osteotomies. Monotonic bending testsrevealed that AdhFix could withstand up to 220 (±15) NQUINN ET AL . 317 1532950x, 2024, 2, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14048 by Cochrane France, Wiley Online Library on [14/02/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licenseof force comparable to that of metal plates up to the pointof failure. The stiffness of the AdhFix and metal platesunder cyclic testing between 10 and 70 N was also equiv-alent. In vivo testing in rodents has shown that AdhFixcould successfully stabilize and maintain alignment oftransverse femoral osteotomies. While soft tissue adhe-sions were seen in the metal plate control group, noadhesions were witnessed with AdhFix. Histology dem-onstrated no adverse effects from AdhFix on the sur-rounding soft tissue while micro-CT of the fracture after5 weeks and 12 months confirmed successful bone heal-ing.12,14The additional benefit of the composite fixationis that it would not impede evaluation of fracture sitehealing in clinical cases as it is radiolucent enough to notobscure the fracture site it covers.There were a few limitations of the study. In thisstudy, mechanical testing was restricted to acute load tofailure. Cyclic loading using physiological loads wouldbetter mimic the clinical setting; however, this was theinitial mechanical testing in a canine cadaver model andit seemed prudent to evaluate how the composite wouldrespond when tested against similar previously testedimplants.10Cyclic testing is rarely reported comparedwith single load to failure in veterinary literature despiteit being a more appropriate method for assessing manyfixation models and this will be evaluated in future stud-ies of the AdhFix composite.The constructs were only tested in a single directionwith loading of the capitulum only, which does not fullyevaluate the real-world forces experienced in this region.Elbow joint loading and mechanics are complex, and theused model does not mimic a clinical setting, which wasrecognized as a limitation. The a uthors recognize the osteot-omy does not mimic a clinical fracture; however, theinflicted osteotomy was the sa m ef o ra l ls u b j e c t s .T h ed i r e c -tion and the position of the application of force was selectedto be consistent with prev iously reported studies.10,14,15,17In the study, specimens were tested beyond whatwould be deemed to be relevant failure in a clinical case.Fracture displacement of 10 mm would not be routinelyacceptable in an articular fracture; however, this is thestandard that many other studies have used as an out-come measure so use of the same failure point aids incomparison between studies. The yield point is the mostrelevant value when assessing from a clinical perspectiveas any displacement of an articular fracture would bedeemed a failure. In this study, yield point was signifi-cantly higher for the Adhfix group compared to the Pingroup and there was no statistical difference between theAdhfix group and the Plate group.No comparison of surgical exposure of tissue wasdone, as the study focused on mechanics of bones with-out skin or soft tissues however the degree of surgicalexposure would not be expected to be any different tothat required for bone plating of these fractures.Overall, this study represents the initial investigationsinto the mechanical properties of a novel composite foradjunct fracture fixation of the lateral part of the caninehumeral condyle. In conclusion, Adhfix was superior toK-wires, and comparable to plate fixation, for adjunctivefixation in a lateral humeral condylar model. The resultsare encouraging and these in combination with the previ-ously reported safety data12,13provide a platform forfuture studies. Further testing will be carried out prior tothe product becoming commercially available.AUTHOR CONTRIBUTIONSQuinn RJ, BVMS(Hons) CertAVP DipECVS MRCVS:Involved in the conception of the study, study design,acquisition of data, data analysis and interpretation,drafting and revising of manuscript, and approval of thesubmitted manuscript. Höglund OV, DVM, PhD,MRCVS: Involved in the study design, acquisition of data,revising of manuscript, and approval of the submittedmanuscript. Hutchinson DJ, PhD: Involved in the studydesign, acquisition of data, data analysis and interpreta-tion, revising of manuscript, and approval of the submit-ted manuscript. Opande L, MSc: Involved in theacquisition of data and data analysis, and approval of thesubmitted manuscript. Lim E, BSc: Involved in the acqui-sition of data and approval of the submitted manuscript.Birgersson U, PhD: Involved in the data analysis andinterpretation, revising of manuscript, and approval ofthe submitted manuscript. Granskog V, PhD: Involved inthe study design, acquisition of data, data analysis andinterpretation, revising of manuscript, and approval ofthe submitted manuscript. Malkoch M, PhD: Involved inthe conception of the study, study design, revising ofmanuscript, and approval of the submitted manuscript.FUNDING INFORMATIONMichael Malkoch and Daniel J. Hutchinson would like toacknowledge funding from the Knut and Alice WallenbergFoundation (grant no. 2017-0300 and 2019-0002) and theEuropean Union (H2020 FET-Proactive project BoneFix,grant no. 952150). Robert J. Quinn would like toacknowledge Linnaeus Veterinary Limited for supportingthe costs of the Open Access Publication Charges.CONFLICT OF INTEREST STATEMENTRobert J. Quinn, Daniel J. Hutchinson and Odd V.Höglund have no conflicts of interest to disclose. UlrikBirgersson, Edward Lim, Viktor Granskog and LolaOpande are employed by Biomedical Bonding AB. ViktorGranskog and Michael Malkoch are shareholders in Bio-medical Bonding AB.318 QUINN ET AL . 1532950x, 2024, 2, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14048 by Cochrane France, Wiley Online Library on [14/02/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseORCIDRobert J. Quinn https://orcid.org/0000-0001-7879-4208Odd V. Höglund https://orcid.org/0000-0003-0978-836XDaniel J. Hutchinson https://orcid.org/0000-0003-0028-1204Ulrik Birgersson https://orcid.org/0000-0002-7983-925XViktor Granskog https://orcid.org/0000-0001-8595-0037Michael Malkoch https://orcid.org/0000-0002-9200-8004

Answer 43

The objectives of the present study were to com -pare complication rates and short-term outcome fol -lowing elective unilateral arytenoid lateralization in dogs with laryngeal paralysis and determine wheth -er there was a difference between outpatient proce -dures compared with inpatient procedures. Results of the present study suggest no statistically signifi -cant difference in mortality or morbidity during the postoperative period between the inpatient group (5%) and outpatient group (8.3%). Therefore, we ac -cept our hypothesis that outpatient unilateral aryte -noid lateralization is a safe alternative to overnight hospitalization following surgery.Historically, the purpose of hospitalizing pa -tients after unilateral cricoarytenoid lateralization was to administer prokinetic and antinausea therapy to try and reduce episodes of vomiting and regur -gitation that may lead to development of aspiration pneumonia, as well as to monitor respiratory status. The effects of metoclopramide administration on the presence of postoperative aspiration pneumonia has been evaluated in several studies with mixed results. A retrospective study28 including 43 client-owned dogs after unilateral arytenoid lateralization sug -gested that postoperative aspiration pneumonia may be reduced from 50% to 17% by metoclopramide ad -ministration in the immediate perioperative period. Another multicenter randomized clinical trial found no significant differences in the rate of development of aspiration pneumonia when a metoclopramide constant rate infusion was used.16 Given the minimal effects that prokinetic therapy had on the incidence of aspiration pneumonia, patients without a history of frequent regurgitation or vomiting likely wouldn’t benefit from hospitalization. Instead, it is possible that hospitalization may cause anxiety and distress, which would manifest as restlessness, panting, and vocalization. A catastrophic sequela of this would be strain on the surgical site and failure. Results of Table 2 —Results of intergroup comparison of postop -erative variables. Inpatient Outpatient group groupVariable n (%) n (%) P valueAnxiety score in hospital .2777 0 11 (55.0) 19 (79.2) 1 3 (15.0) 3 (12.5) 2 4 (20.0) 1 (4.2) 3 2 (10.0) 1 (4.2) Use of prokinetics 10 (50.0) 16 (66.7) .3588Use of antiemetics 16 (80.0) 22 (91.7) .3871Perioperative 10 (50.0) 8 (33.3) .3588 opioid usagePerioperative 16 (80.0) 22 (91.7) .3871 dexmedetomidine administrationPerioperative 1 (5.0) 0 (0.0) .4545 acepromazine administrationAspiration pneumonia 5 (25.0) 1 (4.2) .0773Overall morbidity 1 (5.0) 1 (4.2) .1443Overall mortality 1 (5.0) 2 (8.3) 1.00Dexmedetomidine was administered perioperatively in 4 (20%) inpatients and 2 (8.3%) outpatients ( P = .3871). In the inpatient group, 11 (55%) had an anxi -ety score of 0, 3 (15%) had an anxiety score of 1, 4 (20%) had an anxiety score of 2, and 2 (10%) had an anxiety score of 3. In the outpatient group, anxiety scores were assigned on a scale of 0 to 3 and were found to be 19 (79.2%), 3 (12.5%), 1 (4.2%), and 1 (4.2%), respectively. In-hospital regurgitation was noted in 2 (10%) inpatients and none of the dogs in the outpatient group, and vomiting in hospital was noted in 1 (5%) inpatient and no outpatients. In the inpatient group, 4 (20%) dogs were represented to the emergency department for complications relat -ed to surgery within 2 weeks postoperatively com -pared to 2 (8.3%) dogs in the outpatient group ( P = Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 08/30/23 11:58 AM UTC 5a large prospective observational study29 found that 79% of dogs in a veterinary clinic had signs consistent with fear and anxiety. In the present study, the inpa -tient group had higher anxiety scores compared with those in the outpatient group. It is vital to keep pa -tients calm after arytenoid lateralization procedures for a variety of reasons. The longer patients are hos -pitalized, the more likely they are to experience trig -ger stacking, necessitating fast-acting anxiolytics administered IV. Trigger stacking occurs when a pa -tient experiences numerous stressors without time to return to baseline, which can be seen when mea -suring serum and salivary cortisol levels.30,31 This can occur during short and long periods of time.30,31 Trig-ger stacking often results in progressive anxiety and is associated with behaviors such as pacing, pant -ing, barking, and whining. Excessive barking, pant -ing, and whining could lead to increased stress on the arytenoid lateralization site and tearing of suture or breakage of arytenoid cartilages. In addition, the increased hyperventilation caused by anxiety could lead to excessive carbon dioxide loss and respiratory alkalosis. Lastly, hospitalization following surgery is associated with a higher cost compared to outpa -tient procedures. A 2019 paper32 in human medicine explored the perioperative costs and readmission rates in 73,724 individuals undergoing either ambu -latory (outpatient) versus inpatient elective proce -dures (hernia repair, primary or total thyroidectomy, laparoscopic cholecystectomy, or laparoscopic ap -pendectomy). Findings suggested that adjusted mean surgical costs were significantly lower for am -bulatory versus inpatient cases for each procedure. Additionally, the odds of experiencing readmission within a 30-day period of the surgery was lower in ambulatory versus inpatients surgeries.32 Because there is no increased mortality with outpatient uni -lateral cricoarytenoid lateralization procedures, sig -nificant reductions in healthcare expenditures could allow for more owners to afford this procedure.This study had several limitations secondary to its retrospective nature. Sixty-one cases were ex -cluded because of incomplete medical records, loss of follow-up, and concurrent upper airway surgery. Additionally, patients were excluded if they present -ed as a transfer from the emergency department for respiratory distress. There was no standardized peri -operative complication period, postoperative proto -col, or grading for anxiety and pain management and lack of consistency in personnel observing and eval -uating patients that were hospitalized. This could have led to under- or overreporting anxiety in the patients hospitalized following surgery. There was no standardized anesthetic, antiemetic, prokinetic, or gastroprotectant protocol among the surgeons in the study, which could have affected outcome of adverse events such as regurgitation, vomiting, and/or ileus. There were 5 patients (3 inpatients and 2 outpatients) that received hydromorphone IV as part of a premedication protocol. Due to its µ opioid re -ceptor agonist properties, vomiting can occasionally be seen following administration. One study33 found that the route of administration in dogs undergoing routine orthopedic surgery had no effect on the like -lihood of vomiting. All patients that received hydro -morphone in their anesthetic protocol were admin -istered maropitant IV prior to reduce the chances of vomiting. Numerous studies have evaluated the effi -cacy of maropitant on inhibiting vomiting in patients receiving hydromorphone (both IV and IM).34 These found that maropitant prevented vomiting, retch -ing, and nausea when given prior to hydromorphone administration.34 The surgeries performed in the current study were performed by 5 board-certified surgeons, and variations in surgeon experience and surgical technique may have also led to variation in outcome. Both cricoarytenoid and thyroarytenoid lateralization were performed in this study. Although studies have shown that each of these procedures affects the rima glottidis area differently, the clini -cal outcomes observed in dogs treated with either procedure have not been shown to differ.14 The deci -sion to perform cricothyroid disarticulation was also left up to the surgeons’ discretion in this study, which also could have affected outcome as disarticulation has been shown to destabilize the larynx and affect glottic diameter.35 Finally, one surgeon routinely used polyglyconate suture for arytenoid lateraliza -tion while the others used polypropylene. Although the former is absorbable, it retains a great amount of tensile strength after 4 weeks. Given the short-term follow-up period of 2 weeks used in this study, this likely shouldn’t have caused any clinical difference between groups. It is important to note that it is rec -ommended to place a permanent suture (polypro -pylene) to reduce risk of failure of lateralization in the long term given the dynamic nature of the organ. Future prospective studies should be performed to look at inpatient versus outpatient unilateral cricoar -ytenoid lateralization and thyroarytenoid lateraliza -tion procedures. A prospective study would allow for standardized patient recordkeeping and protocols evaluating anxiety.Results of the current study suggest no greater increase in mortality nor morbidity in patients dis -charged the same day as surgery. It is important to note that careful patient selection is vital to deter -mining whether outpatient surgery is feasible.AcknowledgmentsNo third-party funding or support was received in con -nection with this study or the writing or publication of this manuscript. The authors have nothing to declare.The authors thank Dr. Stephen Werre at Virginia-Mary -land College of Veterinary Medicine for his contribution to the statistical analysis.

Answer 44

In the present study, the clinical utility of a simple, STST was investigated, and compared to the WT (Clough et al., 2018 ; Lascelles et al., 2006 ; Light et al., 2010 ; Wilson et al., 2018 ) which is another method of quantitative gait analysis. Objective measures of lameness (SI of the GRF expressed during each test) were recorded and compared by different analysis techniques. The STST test was achievable in all patients. However, the time advantage was less than expected, and the STST did not effec -tively discriminate between dogs with hindlimb lameness associ -ated with CCLR and non-lame dogs.The SIs of PVF and VI are common kinetic gait parameters used in the diagnosis of unilateral lameness in dogs (Fanchon & Grandjean, 2007 ) and have been found to effectively discriminate between lame and non-lame hindlimbs (Budsberg et al., 1993 ). Although the STST accentuated the difference in SIs between the CCLR and non-lame groups, the difference was also more variable across the three repeats assessed which reflected the observation that the dogs did not rise in the same manner on every test. This variability impacted on the ability of the test to discriminate between non-lame and dogs with lameness associ -ated with CCLR.Compensatory weight-shifting mechanisms in dogs with unilateral lameness are well recognised. In dogs with hindlimb lameness, compensatory load has been shown to shift to the ipsilateral forelimb when analysing PVF and VI at walk (Fischer et al., 2013 ; Katic et al., 2009 ) and trot (Fischer et al., 2013 ). This is at odds with our observation that the SI of PVF and VI of DLPs was more sensitive than ILPs, but ILP and DLP were both still considerably less discriminatory for identifying lame dogs than HLs alone in the WT. The reasons for this difference with previous reports are unclear, but the nature of the hindlimb lameness, our use of a pressure platform rather than an instru -mented treadmill, and the heterogeny of the breeds in our study may have contributed. The SI of PVF and VI with DLP and ILP in the STST did not improve the ability to discriminate lameness associated with CCLR when compared to the HL alone suggest -ing that compensatory load shifting was not occurring consis -tently in the STST either.Asymmetry in StT between the lame and non-lame groups was not discriminatory for the identification of lameness in this cohort. An increase in CHL StT might be expected as a compensatory load-shifting mechanism to reduce load-bearing of the AHL as has been shown with cinematography and elec -trogoniometry in horses (Clayton, 1986 ; Ratzlaff et al., 1982 ). In dogs however, morphometric differences such as overall body size and limb length rather than body mass, are responsi -ble for as much as 20% of StT variance (Budsberg et al., 1987 ; Fischer et al., 2013 ). These variables were not controlled for in this study, and may partially explain why these differences in this measure were not observed (Abdelhadi et al., 2013 ; Boss -cher et al., 2017 ).The STST and the WT employ different movements and therefore some dogs with orthopaedic disease may objectively demonstrate lameness with one method but not another. The clinical application of kinetic gait analysis is challenging because it requires multiple passages across the platform to obtain enough data to reproducibly identify unilateral lameness; large variances in the data occur as a result of different stance times, velocity and/or acceleration (Hans et al., 2014 ; Volstad et al., 2016 ). Additionally, thus far the time burden to obtain sufficient num -bers of “repeats” to obtain valid and useful data, and the space required to create a runway has precluded its use in the clinical setting. For this reason, five repeats of the WT test were under -taken and 3 repeats of the STST.This study has several limitations. Firstly, as a pilot study of the STST, there was no prior knowledge of variance of this data upon which to select a sample size. However, the fundamental premise was that a useful test should be able to discriminate all dogs with unilateral lameness caused by CCLR from non-lame dogs, and thus five valid WT trials and three STST trials per dog were obtained in this study. Five valid WT trials is the generally accepted number to produce valid data (Torres, 2020 ) though the time required to collect five valid WT trials is considerable with a pressure platform 1 m in length. Increasing the number of STST trials may have reduced the variance of the SI data produced but the number of trials selected was limited to those considered acceptable by our ethical review board, and time-appropriate for the clinical setting. Rising from a prone position is considered a more painful movement than walking, and thus the number of repeats was limited for ethical reasons, as the expectation was that the lameness would be accentuated by this movement, but this will have contributed to the increased variability. The sever -ity of lameness was not standardised for the purpose of the study, although all dogs were able to weight bear on their affected limb. No imaging of the non-lame group before enrolment into the study was performed. SI in healthy dogs should also be inter -preted with caution. It is one point in time test and may not 17485827, 2024, 1, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jsap.13679 by Vetagro Sup Aef, Wiley Online Library on [19/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseA. Triviño et al.Journal of Small Animal Practice • Vol 65 • January 2024 • © 2023 The Authors. Journal of Small Animal Practice published by John Wiley & Sons Ltd on behalf of British Small Animal Veterinary Association.28reflect the gait at home. Additionally, dogs can demonstrate sig -nificant asymmetry between healthy limbs (Torres, 2020 ). This natural variation can therefore result in both false positives and negatives.In conclusion, a three repeated STST has a limited clinical utility for the identification of lameness associated with CCLR in dogs, and the SI of kinetic data of the hindlimbs alone using the WT remains the most sensitive tool for identification.AcknowledgementsWe would like to thank the HfSA staff, students and clients for consenting to their dogs taking part in this study.Author contributionsAlexis Triviño: Data curation (equal); investigation (equal); project administration (equal); writing – review and editing (supporting). Catherine Davidson: Data curation (support -ing); formal analysis (supporting); writing – original draft (lead); writing – review and editing (lead). Dylan Neil Cle -ments: Conceptualization (lead); data curation (equal); formal analysis (lead); investigation (equal); methodology (equal); project administration (equal); supervision (lead); validation (lead); writing – review and editing (equal). John M Ryan: Conceptualization (equal); data curation (supporting); meth -odology (equal); project administration (equal); resources (equal); supervision (supporting); writing – review and editing (supporting).Conflict of interestNone of the authors of this article has a financial or personal relationship with other people or organisations that could inap -propriately influence or bias the content of the paper.Data availability statementDerived data supporting the findings of this study are available from the corresponding author.

Answer 45

The present study addressed the success rate after CT- based planned surgery in dogs with head and neck abscesses and DTs suspected to result from migrating VFB and OSI in dogs.FIG 2. Pre contrast (A) and post contrast (B) transverse plane CT image in soft tissue reconstruction. A semi- lunar hypoattenuating structure with a thick and strongly contrast enhancing rim (arrows) is visible medial to the right mandibular ramus. This was a wooden foreign body that migrated from the oral cavityFIG 3. Pre contrast (A) and post contrast (B) transverse plane CT image in soft tissue reconstruction. A voluminous cavitary mass is seen containing numerous gas bubbles that represent an abscess in the left zygomatic region (arrows), extending within the dorsal soft tissues of the head (arrowhead) 17485827, 2023, 9, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jsap.13624 by Vetagro Sup Aef, Wiley Online Library on [17/09/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseS. Manzoni et al.Journal of Small Animal Practice • Vol 64 • September 2023 • © 2023 British Small Animal Veterinary Association. 586The population in our study consisted of relatively young (median age: 4 years) medium to large dogs (median weight: 20 kg), including a large proportion (67%) of hunting dogs with retriever behaviour – breeds that are known to be at risk of OSI and migrating VFB (Frendin et al. 1994, Frendin et al. 1999, Gnudi et al. 2005, Dobromylskyj et al. 2008, Nicholson et al. 2008, Schultz & Zwingenberger 2008, Lamb et al. 2017). Because all other possible causes of abscesses and DTs were excluded on the basis of history and CT results, VFB and/or OSI was suspected in all animals included in our study. This suspi-cion was further reinforced by the identification of P . multocida in nine cases; this bacterial strain is one of the most common strains isolated from migrating VFB and is part of the commensal flora in the canine oral cavity and respiratory tract (Brennan & Ihrke 1983, Kolata 1993, Flisi et al. 2018).On the basis of the results of previous studies evaluating the use of pre- operative CT for surgical treatment of abscesses and DTs in the thoracic and abdominal regions, we postulated that the same strategy might provide similar long- term success rates in the head and neck regions. A 95% success rate was obtained after a single surgery in our study – a value exceeding the 75 to 87% success rates reported in studies on the thoracic, abdomi-nal and sublumbar areas (Bouabdallah et al. 2014, Griffeuille et al. 2021, Jacques et al. 2022). Several hypotheses might explain this difference in rates. Early treatment may positively affect suc-cess rates (Griffiths et al. 2000, Nicholson et al. 2008, Schultz & Zwingenberger 2008). In fact, the median duration of clini-cal signs before presentation was 15 days in our study – earlier than reported in previous studies in other body areas (60 days to 3 months) (Bouabdallah et al. 2014, Griffeuille et al. 2021, Jacques et al. 2022). This difference in duration may be associ-ated with the relatively more severe clinical signs in the head and neck regions, given that externally visible and painful swelling was observed in most of our cases. Moreover, only 19% of the dogs had already undergone at least one surgery in our study, in contrast to 31 to 57% of the cases in studies focusing on the tho-racic, abdominal or sublumbar regions (Bouabdallah et al. 2014, Griffeuille et al. 2021, Jacques et al. 2022). Repeated surgeries may contribute to complicating the interpretation of CT images and subsequent surgical procedures.Removal of VFB at the time of surgery is an important factor affecting success, because VFB persistence maintains infection. The use of imaging modalities for VFB identification may thus be critical. To facilitate and guide surgical approaches, preopera-tive imaging using ultrasound (US), CT or magnetic resonance imaging (MRI) have been described for surgical planning when abscesses are suspected to result from VFB and/or OSI (White & Lane 1988, Armbrust et al. 2003, Dobromylskyj et al. 2008, Nicholson et al. 2008, Birettoni et al. 2017, Blondel et al. 2021), thus increasing the chances of finding VFB during surgery and decreasing the risk of recurrence (Blondel et al. 2021, Jacques et al. 2022). The purpose of preoperative diagnostic imaging is man-ifold. When VFB is identified, the surgeon can perform the least invasive procedure to remove it (Schultz & Zwingenberger 2008, Attanasi et al. 2011, Vansteenkiste et al. 2014). In cases in which no VFB is identified, imaging can help localise and assess the extent of lesions likely to contain the VFB, thus providing valu-able information for surgical exploration and determining the feasibility of en- bloc resection (Bouabdallah et al. 2014). Finally, imaging studies enable assessment of the surrounding anatomical structures before surgical exploration and therefore decrease mor-bidity (Nicholson et al. 2008, Bouabdallah et al. 2014).Although CT lacks sensitivity in identifying VFB, particularly those of vegetal origin, this modality can identify secondary lesions (abscess cavities, DTs or reactive bone lesions), which may be closely associated with VFB. In one study, grass seeds were visible on CT images in only 19% of cases, whereas secondary lesions were iden-tified in 96% of cases (Vansteenkiste et al. 2014). This finding was also verified in our study, in which secondary lesions were observed in all dogs. The ability of CT to detect VFB depends on many factors, such as the nature of the VFB, its size, its shape, the exten-sion of associated inflammatory process and the chronic nature of the diseases. Studies have reported the highest sensitivity (79 to 100%) for wooden foreign bodies (Nicholson et al. 2008, Lamb et al. 2017) and the lowest sensitivity for grass seeds (8 to 36%) (Schultz & Zwingenberger 2008, Attanasi et al. 2011, Vansteen-kiste et al. 2014). In our study, the sensitivity and specificity of CT for detecting migrating VFB were 58 and 95%, respectively, in line with the values reported in a prior study on wooden foreign bodies in OSI (Nicholson et al. 2008). These values are within the ranges of those reported in the thoracic, abdominal and sublumbar regions, in which the sensitivity has been reported to vary from 47 to 84%, and the specificity has been reported to vary from 50 to 65% (Bouabdallah et al. 2014, Griffeuille et al. 2021).In contrast to findings from a prior study, in which wooden foreign bodies were more often identified on CT in chronic than FIG 4. Pre contrast (A) and post contrast (B) sagittal plane CT image in soft tissue reconstruction. A large wooden stick foreign body is present within the cervical soft tissues (yellow arrow). Extending cranially to the foreign body, a tubular structure with a non- contrast- enhancing centre and strong peripheral contrast enhancement is visible, in agreement with a sinus tract (green arrowheads) 17485827, 2023, 9, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jsap.13624 by Vetagro Sup Aef, Wiley Online Library on [17/09/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseCT for surgery of head and neck abscessesJournal of Small Animal Practice • Vol 64 • September 2023 • © 2023 British Small Animal Veterinary Association. 587 in acute cases (Lamb et al. 2017), we did not find any statisti-cally significant difference in the identification of VFB from CT or from surgery between chronic and acute cases. The moderate sensitivity of CT to detect VFB prompts questions regarding the relevance of this modality compared with US for surgical plan-ning. Ultrasonography was historically the first intention imag-ing modality used in the diagnosis of abscesses and DTs, because of its relatively low cost, wide availability, and the absence of ionising radiation and of a need for anaesthesia (Nicholson et al. 2008). US has a sensitivity for detecting VFB ranging from 50 to 100% (Frendin et al. 1999, Armbrust et al. 2003, Staudte et al. 2004, Thiel et al. 2006, Ober et al. 2008, Schultz & Zwingen-berger 2008, Farr et al. 2010, Mohammadi et al. 2011, Atkinson et al. 2014, Javadrashid et al. 2015, Blondel et al. 2021), and it is superior to CT in the detection of soft tissue attenuation or very small VFB (Mizel et al. 1994, Aras et al. 2010, Javadrashid et al. 2015, Haghnegahdar et al. 2016). The relative merits of US compared with CT have not been established for detecting migrating VFB in clinical situations in animals. In humans with wooden foreign bodies, US, CT and MRI are recommended without clear priority (Lamb et al. 2017). The only veterinary study comparing the relative sensitivity of preoperative CT and US has reported that US is superior (Blondel et al. 2021). When an abscess or DT is present, tissues are swollen, and US is easier to use in these circumstances, particularly with superficial VFB. However, this examination has some operator and equipment- dependent limitations (Orlinsky et al. 2000, Armbrust et al. 2003); moreover, the presence of air in the upper respiratory tract and the high concentration of bony structures can some-times hinder complete examination of the head and neck regions (Armbrust et al. 2003, Aras et al. 2010, Bradley 2012, Shiva Bharani et al. 2015). Furthermore, in comparison with CT, US does not provide information on possible bone lesions, and the identification of VFB deeper than 4 cm under the skin is inac-curate (Aras et al. 2010, Haghnegahdar et al. 2016). The main advantage of US is the possibility of intraoperative use. Dogs undergoing intraoperative US have indeed been found to have better success rates for surgical removal of VFB (89.5%) than dogs undergoing only a preoperative US examination (59.1%) (Blondel et al. 2021). A success rate of 100% has also been docu-mented for US- guided surgical removal of migrating VFB in ilio-psoas muscles (Birettoni et al. 2017).The 44% identification rate of VFB at the time of surgery in our study was in line with the 41 to 59% reported in prior stud-ies (Bouabdallah et al. 2014, Griffeuille et al. 2021) and com-pared favourably with the 22 to 37% rates reported for surgery performed without preoperative diagnostic imaging (Griffiths et al. 2000, Doran et al. 2008). A higher success rate when VFB is excised at the time of surgery has been reported by many authors: 100% success rates have been observed for dogs in which VFB were retrieved, whereas 50 to 79% rates have been observed when no VFB were found (White & Lane 1988, Lamb et al. 1994, Griffiths et al. 2000, Dobromylskyj et al. 2008, Bouabdallah et al. 2014, Griffeuille et al. 2021). The 95% success rate in our study is higher than the success rates of 66 and 81%, respectively, reported in previous studies on oropharyngeal penetrating injuries in which little or no preoperative imaging was used (White & Lane 1988, Griffiths et al. 2000). This difference suggests that the preopera-tive use of an imaging technique might increase the success rate of the management of these lesions. As reported in previous stud-ies (Griffiths et al. 2000, Armbrust et al. 2003, Dobromylskyj et al. 2008, Bouabdallah et al. 2014), removal of VFB at the time of surgery did not significantly affect the recurrence rate in our study. However, although all dogs in which VFB were removed were cured, recurrence was observed in two dogs in which VFB were not identified at the time of surgery.The cases of recurrence observed in our study may be explained by the persistence of VFB, insufficient debridement of infected tissues and/or inappropriate antibiotic therapy. Although some authors have recommended postoperative antibiotic therapy for several weeks for the treatment of certain infections (Kirpensteijn & Fingland 1992, Frendin et al. 1994), further investigation is Table 3. Summary of number of cases and their outcomesNumber of casesNumber of VFB found at surgeryNumber of healed casesNumber of recurrencesSuccess rate (%)Number of cases with VFB identified on CT 11 10 11 0 100Number of cases with no VFB identified on CT 28 7 26 2 93Total 39 17 37 2 95VFB Vegetal foreign bodiesTable 2. Presence or absence (±) of VFB at CT examination compared with surgical (S) findings and rate of recurrence (R) in a retrospective study of 39 dogs that underwent surgical exploration of head and neck abscess or DTCT (±) Number of cases (%) Surgery (±) Number of cases (%) Recurrence (±) Number of cases (%)CT+ 11 (28) S+ 10 (91) R+ 0 (0)R− 10 (100)S− 1 (9) R+ 0 (0)R− 1 (100)CT− 28 (72) S+ 7 (25) R+ 0 (0)R− 7 (100)S− 21 (75) R+ 2 (10)R− 19 (90)VFB Vegetal foreign bodies, DT Draining tract 17485827, 2023, 9, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jsap.13624 by Vetagro Sup Aef, Wiley Online Library on [17/09/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseS. Manzoni et al.Journal of Small Animal Practice • Vol 64 • September 2023 • © 2023 British Small Animal Veterinary Association. 588necessary to define whether long antibiotic therapy can aid in controlling relapses.The outcome was positive for patients in whom a VFB was found at surgery but also for those in which a VFB was not found. This result may have been dictated by the small number of dogs in our study, obscuring a possible highlighting of different outcomes between two groups (VFB found/not found) in a larger sample size. The second limitation of our study concerns the fact that for the retrospective nature of the study the data collected were influenced by different clinicians involved in the management of the patients and that clinical practices for diagnosis and treatment were not stan-dardised. CT examination was limited to only the head and neck and this might have influenced the possibility of identifying VFB that may have migrated to other regions of the body. The relative sensitiv-ity and specificity of CT in detecting VFB were determined on the basis of operative findings, but some migrating VFB might have been missed at the time of surgery; moreover, histopathological examina-tion, which is necessary to identify infra- millimetric VFB, was per-formed in only half of the cases. Finally, long- term follow- up was performed by telephone interview rather than clinical examination, thus potentially altering the accuracy of the information collected.CT- based surgical planning for the management of abscesses and DTs of the head and neck suspected to be associated with migrating VFB and/or OSI had a high success rate with low mor-bidity in our study, even in cases in which VFB were not identi-fied. Although CT sensitivity in detecting VFB was moderate, it allowed for precise visualisation of the extent and localisation of the abscesses and DTs likely to contain VFB, and the selec-tion of the least invasive surgical approach. The potential benefits of combining preoperative US and CT and perioperative US to improve VFB retrieval and minimise surgical trauma should be evaluated in further studies.AcknowledgementsThe authors acknowledge Dr Mattea Lenhoff for her careful reading of the manuscript.Author contributionsSara Manzoni: Conceptualization (lead); data curation (lead); formal analysis (lead); writing – original draft (lead). Marisa Santos: Conceptualization (supporting); supervision (supporting); visualization (supporting). Alexandre Leveugle: Data curation (supporting). Bastien Dekerle: Visualiza-tion (supporting). Paul Garnier: Visualization (supporting). Emeline Maurice: Visualization (supporting). Adeline Decambron: Supervision (equal); validation (equal); visualiza-tion (equal). Jeremy Mortier: Data curation (supporting); soft-ware (supporting); supervision (equal). Mathieu Manassero: Supervision (equal); validation (equal); visualization (equal). Véronique Viateau: Supervision (lead); validation (lead); visual-ization (lead); writing – review and editing (lead).Conflict of interestNone of the authors of this article has a financial or personal relationship with other people or organisations that could inap-propriately influence or bias the content of the paper.

Answer 46

From this study population, we demonstrated that capitalfemoral physeal or neck fractures can be successfullytreated with closed reduction and FGPP. This techniquewas associated with good postoperative outcomes amongcases with no radiographic evidence of fracture remodel-ing. However, major complications were common.FIGURE 1 Preoperative (A) and immediate postoperative (B) extended craniocaudal radiographs from a dog treated for a Salter-Harristype I right capital physeal fracture. Stabilization was achieved using fluoroscopic-guided percutaneous pinning (FGPP) via three Kirschnerwires. Three-week postoperative radiographs (C) show a healed capital physeal fracture. Elective explant (D) was pursued at the three-weekpostoperative periodFIGURE 2 Sequential radiographs of a dog treated for a Salter-Harris type I fracture of the left capital physis. Fracture stabilization wasachieved using fluoroscopic-guided percutaneous pinning (FGPP) via three Kirschner wires (A: preoperative, B: immediately postoperative).This dog required revision surgery 3 days postoperatively for continued lameness, fluoroscopy confirmed an intra-articular Kirschner wire,and the Kirschner wires were backed out (C). Four-week postoperative radiographs (D) show healing of the capital physeal fracture withprogressive cranial acetabular remodeling. A salvage procedure via femoral head ostectomy (FHO) was elected due to continuedlameness (E)850 de MOYA ET AL . 1532950x, 2023, 6, The majority of fractures in this cohort of dogs hadmild radiographic displacement preoperatively. In a pre-vious study investigating outcomes of physeal fracturesrepaired via FGPP, the majority of fractures (38/42) hadpreoperative displacement <2/3 the width of the affectedbone, and the majority of cases were deemed to haveexcellent final functional outcome (92%).15Previous stud-ies of humans investigating physeal fractures in adoles-cents showed that severity of preoperative radiographicdisplacement was associated with an increase in the riskof developing complications, and preoperative displace-ment is therefore an important factor in selecting themethod of repair (minimally invasive techniquesvs. ORIF).19–21Our results support utilizing preoperativeradiographic displacement as a selection criterion whenconsidering FGPP as a repair option. However, we areunable to determine if fractures with moderate to severepreoperative displacement are at higher risk of complica-tions. We suspect that fractures with minimal displace-ment are probably more amenable to closed reductionand thus better candidates for FGPP compared to frac-tures with more significant displacement. One can fur-ther extrapolate that blood supply compromise, and thusability to heal the fracture, is somewhat correlated to theseverity of displacement and chronicity of the lesion.Elective explant was performed in five fractures andunplanned explant was performed in two fractures due toimplant migration. Additionally, migration occurred withKirschner wires that were left long in the subcutaneousspace and with those cut short. Previous investigatorsreported an elective explant rate of 40% among dogs andcats undergoing FGPP for physeal fracture repairs.15Explant following fracture healing has been advocated tomitigate the risk of iatrogenic physeal closure in skele-tally immature humans and small animals.16,21We areunable to discern the impact of early Kirschner wireremoval on physeal closure or other complications fromour relatively small study population. Our currentapproach is to plan an elective pin removal in dogs thatare less than 8 months of age at the time of injury topotentially reduce the risk of premature physeal closure.Postoperative femoral neck resorption was minimaland noted in only two of 10 dogs that had complete frac-ture healing. Also known as “apple-coring ”, neck resorp-tion is a well described sequelae following ORIF ofcapital femoral physeal fractures.1,5,8In a previous retro-spective study, there were no specific risk factors identi-fied for the development of narrowing of the femoralneck.8The single extracapsular vascular ring at the levelof the femoral neck gives rise to the intracapsular andintraosseous network of vessels supplying the joint cap-sule, physis, femoral neck and epiphysis, and surgicaltrauma to this vascular network may result in femoralneck resorption.21,22We speculate that the describedminimally invasive approach may limit iatrogenic injuryto this regional blood supply and potentially result inmore rapid healing. It is possible that femoral neckresorption occurred but was not captured radiographi-cally in our study population due to the short term followup. Larger clinical studies are required to determinewhether FGPP is truly associated with less femoral neckresorption when compared to ORIF, or if other associa-tions such as time between trauma and repair also play arole in this postoperative phenomenon.Two cases with complications had prolonged duration(>15 days) between the time o fi n j u r ya n ds u r g i c a li n t e r -vention. Both cases had signs o ff r a c t u r er e m o d e l i n gp r e o p -eratively and thus may not have been ideal candidates forFGPP, or even ORIF. Remodeling likely resulted in poorinherent stability of these frac tures thereby predisposing toimplant failure and/or excess ive micromotion at the frac-ture site, as well as impai red biological activity.23Intra-articular pin placement occurred in one case.We propose that the risk of intra-articular pin penetra-tion may be higher at this anatomic location due to thesmall size of the intended target, bulk of the surroundingsoft tissues associated with the proximal femur, andspherical morphology of the femoral head. Previous stud-ies investigating slipped capital femoral epiphyseal andneck fractures in humans demonstrated undiagnosed pinpenetration of the hip joint and challenges obtainingcomplete and accurate images of the femoral head.24,25Arecent study comparing fluoroscopy, CT and direct ana-tomic measurements of screw positioning in a cadavericslipped capital femoral epiphysis model revealed that fluo-roscopy and CT measurements overestimated the distancebetween the screw tip and the articular surface when com-pared to direct measurement.26We suspect that these sameimaging limitations and anatomic characteristics of the fem-oral head could have resulted from suboptimal image qual-ity intraoperatively that did no th i g h l i g h tp e n e t r a t i o no ft h ejoint. Percutaneous pinning i sar e l a t i v e l yn e wm i n i m a l l yinvasive repair option and varia bility in surgeon experiencecould have resulted in complicat ions. Violation of the coxo-femoral joint in this case ultimately resulted in a femoralhead and neck ostectomy due t op r o g r e s s i v ed e g e n e r a t i v ejoint disease and lameness. Ou rr e s u l t sh i g h l i g h tt h ep o t e n -tial catastrophic clinical consequence of intra-articular pinpenetration.The results of the present study should be interpretedwith consideration to several limitations. This was only asmall retrospective case series with short-term followup, and therefore lacked standardized treatment andfollow-up protocols, includ ing objective evaluation offunctional recovery. All ou tcome measures were basedon subjective clinical ex amination from medicalde MOYA ET AL . 851 1532950x, 2023, 6, records. Other limitations in cludes the lack of a controlgroup that had undergone O RIF for comparisons andvariability in surgeon training/experience.The results of the present study show that FGPP is apromising repair option for femoral head and neck frac-tures in dogs and was associated with good outcomes.Future studies with a larger sample size evaluating longerterm outcomes using objective evaluation parameters arewarranted.ACKNOWLEDGMENTSde Moya KA, DVM: Data acquisition, analysis and inter-pretation, drafting of manuscript; Kim SE, BVSC, MS,DACVS: Study design, performed procedures, data inter-pretation and analysis, critical manuscript revisions;Guiot LP, DVM, DACVS, DECVS: Study design/concep-tion, performed procedures.CONFLICT OF INTERESTThe authors declare no conflicts of interest related to thisreport.ORCIDKevin A. de Moya https://orcid.org/0000-0002-2297-4813

Answer 47

We evaluated the planning methodology and resultantTPA following a modified CCWO as described by Oxleyet al.; comparing the in silico result to clinically executedcases. When executed in silico, the wedge angle calcula-tions proposed by Oxley et al. accounted for increasingpreoperative TPA; however, the intended 5/C14was notachieved in any group but was closest in the eTPA group.We therefore reject our first hypothesis. Assuming that itis important to achieve 5/C14which has been shown to elim-inate cranial tibial thrust during weight bearing, the cur-rent guidelines should be modified.5Although surgical planning gave a consistent reduc-tion in TPA to 6.4 –8.4/C14irrespective of TPA Pre,TPA Postfrom clinically executed cases differed, and we reject oursecond hypothesis. This suggests that surgical planningor intraoperative execution differed from Oxley's recom-mendations in the cases included in our study. Surgicalcorrection to the target TPA was better in dogs with alower TPAPreand the least effective correction wasachieved in cases with eTPA. Furthermore, the positionof the ostectomy in clinical cases was more distal thanthe recommended 5 and 10 mm from the patellar tendoninsertion in small and large dogs, respectively. Distalizingthe ostectomy in silico demonstrated a progressiveunder-correction of TPA irrespective of TPAPre. This sup-ports previous evidence that the impact of tibial long-axisshift is greater when the ostectomy is performed moredistally.14There are several possible explanations for the poorcorrelation between postoperative and in silico outcomes.First, decision-making intraoperatively may haveresulted in performing a more distal ostectomy to allowperceived sufficient room for implant placement. Subjec-tive assessment of plate fit in this study demonstratedFIGURE 4 Line graphshowing the effect of performingthe ostectomy more distally insilico.118 BANKS ET AL . 1532950x, 2024, 1, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.13998 by Cochrane France, Wiley Online Library on [05/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensethat the appropriately sized plate according to weight andmanufacturer guidelines could be placed sufficiently dis-tal to the stifle joint, and proximal to the virtual ostect-omy performed at 5 mm from the patellar tendoninsertion in all cases. In addition, performing the ostect-omy at 5 and 7.5 mm distal to the patellar tendon insertionachieved the TPA closest to the 5/C14target. The lack of sta-tistically significant difference between the post-planningTPA at these positions suggests some flexibility for platepositioning intraoperatively. Although hypodermic nee-dles are used intraoperatively to identify the tibial plateauin surgery, the soft tissues, and medial buttress will reducethe confidence of the surgeon compared with an in silicoradiographic plate application. Inevitably this will lead toa more distal osteotomy, although exceeding 7.5 mm mayreduce the degree of TPA correction achieved. Further,clinical cases were planned preoperatively with alternativesoftware in which a virtual ostectomy and preoperativeassessment of the resulting TPA could not be made, andthis may have influenced how close the executed surgerywas to the plan. Finally, in planning the wedge size, theapex angle of the isosceles triangle was plotted and thenthe actual distance (mm) of the base of the isosceles trian-gle along the cranial border of the tibial crest was deter-mined in planning and executed at surgery. It isimpossible to know how accurately the measured distancewas achieved retrospectively, nor be able to account forthe sagittal saw blade thickness, which may have contrib-uted to the discrepancy in clinical outcome versus TPAPlan.Further research is warranted to directly compare the clin-ical outcome of cases undergoing mCCWO planned withOxley and alternative methods.Although the Oxley mCCWO is widely applied tosmall dogs, Oxley et al. did not include dogs weighing<20 kg, or dogs with eTPA. An additional category ofeTPA was established for dogs with TPA >35. As thisTPA angle was not described in Oxley et al., and clinicalcases had been managed as per group 31 –35, with areduction of 2/C14, the in silico cases were also calculated asTPA/C02. The current study demonstrated no differencein planned or postoperative TPA in small and large dogsand therefore the methodology for all dogs and thosewith eTPA is supported. CCWO may be considered pref-erable to TPLO in dogs with a preoperative TPA greaterthan 35/C14, or excessive tibial plateau angle (eTPA), due torotation of osteotomy past the “safe point ”in TPLOcould result in tibial tuberosity fracture.8,15However,studies investigating complications following TPLO,including dogs with eTPA have not repeatedly demon-strated an increase in this complication.16,17A combina-tion of CCWO and TPLO has been described to mitigatethese effects, although the major postoperative complica-tion rate was high.11Potential limitations of CCWO include limb shorten-ing and distalization of the patellar tendon, resulting inpatellar baja, patellar tendonitis, or stifle joint hyperex-tension.4Using the Oxley mCCWO, removing a propor-tionately large wedge for cases with eTPA may result in amore pronounced effect. Other mCCWO techniques havebeen described to account for this. However, all reportsare isolated case series and do not make direct compari-sons between the different CCWO iterations. Wallaceet al described a 25/C14neutral wedge ostectomy resultingin TPA correction whilst removing a smaller wedge andreducing limb shortening.8Frederick et al. demonstratedlower short-term complications using this technique.7Christ et al described a juxta-articular mCCWO to maxi-mize bone contact across the osteotomy whilereducing the effect of tibial long-axis shift.9Consistentreduction of TPA within 1/C14of the target TPA and nomajor complications were reported.9,10Guenego et al.described an anatomical-mechanical-axis (AMA-based)mCCWO in order to correct the caudal bowing of theproximal tibia which is frequently demonstrated in dogswith CCLD.12Patellar baja and patellar tendonitis follow-ing mCCWO is likely theoretical and has not been dem-onstrated in recent studies.7,9,12The clinical outcome of the cases included here was notexplored as an aim of this study. Although tibial plateauleveling procedures aim to reduce the TPA to 4 –6/C14,p r e v i o u sstudies have demonstrated good to excellent clinical out-comes with higher postoperative TPAs, including up to14/C14.18Further research is needed to assess the clinical out-come measures in relation to final TPA following the OxleymCCWO in dogs, particularly in cases with eTPA in whichhigher complications have been reported.11,18As m a l ln u m -ber of cases in the current study had a negative TPA Post.This outcome was not observed in in silico cases and sug-gests that intraoperative execution differed from the insilico planning, and hence more care should be taken toaccurately reproduce the plan to achieve a result closer tothe planned outcome. As tibial plateau leveling convertscranial tibial thrust into caudal tibial thrust, a negative TPAwould transfer the strain to the caudal cruciate ligamentwhich acts as the primary stabilizer of the stifle during axialloading.2Caudal cruciate ligament tearing has beenreported in up to 94% of cranial cruciate ligament deficientstifles prior to tibial plateau leveling surgeries.19Therefore,excessive tibial plateau leveling can result in caudal cruciateligament injury.13W ee x p e c tt h en e g a t i v eT P A st ob et h eresult of inaccuracies during surgery which did not corre-late well with the surgical planning. The clinical implica-tion of a negative TPA is unclear but is considered unlikelyto be of benefit to the stabilization of the stifle joint.For all radiographic studies, positioning and the pres-ence of osteophytosis may have impacted the accuracy ofBANKS ET AL . 119 1532950x, 2024, 1, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.13998 by Cochrane France, Wiley Online Library on [05/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseTPA measurements. Radiographs were included only ifappropriately positioned to reduce the impact of position-ing on measurement accuracy. Osteoarthritis and osteo-phytosis are common with CCLD but have beendocumented to have minimal impact on measurementrepeatability.20Finally, radiographs were measured by asingle observer (an ECVS resident experienced in mea-suring joint angles). Previous studies have documentedinterobserver variability in TPA measurements of 0.8 –4.8/C14.20,21Wide variability between measurements mayhave impacted the overall TPA outcome and thereforecomparison to the 5/C14target TPA; however, having a sin-gle observer should minimize variation.In conclusion, the modified CCWO described by Oxleyet al. requires modification to achieve the planned 5/C14TPAtarget. The current study demonstrates that this methodol-ogy achieves a consistent reduction in TPA for cases withexcessive preoperative TPA. Clinical cases appeared to dif-fer from surgical plans, although in some situationsachieved a TPA closer to the target. Ostectomy distaliza-tion is not necessary according to planning to allow forappropriate implant fit and should be avoided where possi-ble due to its effect on tibial long axis and potential under-correction of the final TPA achieved. Further work isrequired to determine whether there is a clinical impact ofunder-correction and whether the Oxley planning methodshould be modified to achieve a 5/C14TPA target.AUTHOR CONTRIBUTIONSBanks C: Contributed to the study design, data acquisi-tion, statistical analysis, and interpretation and wrote themanuscript. Jones, GMC: Contributed to the statisticalanalysis and interpretation of the results and approvedthe manuscript. Meeson RL: Contributed to the concep-tualization and design of the study, supervised the acqui-sition and interpretation and contributed to themanuscript. All authors approved the submitted manu-script and are publicly accountable for relevant content.CONFLICT OF INTERESTThere are no conflicts of interest to disclose.ORCIDCharlotte Bankshttps://orcid.org/0000-0003-1920-388XGareth Michael Couper Jones https://orcid.org/0000-0001-9519-7720Richard Lawrence Meeson https://orcid.org/0000-0002-8972-7067

Answer 48

The main finding of the present study is that the inter-observer reliability of the three pain scales object of the investigation ranged in most cases from poor to fair/moderate, suggesting that subjectivity is a considerable limitation of these tools specifically designed to quantify pain in cats. Our findings are partially in contrast to those of a previously published investigation that identified the FGS as a reliable tool for assessment of acute pain when used by individuals with different background and level of expertise.19Although the present study failed to identify differ -ences in reliability between the three scales or superior -ity of one of the scales, the results show that the level of agreement was not the same between different pairs of assessors. Namely, the veterinary anaesthesia nurse and the final-year veterinary student had better levels of agreement than the other two pairs of assessors, both of which included the board-certified anaesthetist. This finding is interesting, although difficult to interpret. Adami et al 5Considering that the anaesthetists and the nurse were both familiar with the use of the scales while the student was not, it would have been reasonable to expect similar scores between assessors A and B instead. As a general consideration, part of the subjectivity of behaviour-based pain scales is considered to be generated by a tendency of the assessors to subjectively interpret certain behaviours rather than observing them and recording their observa -tion. As an example, a stressed, supposedly pain-free cat may growl or vocalise in the hospital setting without this necessarily being a sign of pain.22 Some assessors may score this specific descriptor in the CMPS – Feline scale, while some others may not, assuming that growling or vocalisations would be most likely unrelated to pain, particularly prior to elective surgery. A different approach to the scale – with some of the observers applying it more literally and others allowing more interpretation – may be the reason for the variability observed in the preoperative pain scores. In supposedly pain-free cats, the scores were expected to trend more consistently towards the lower end of the scale range for all three assessors. While common sense suggests that some degree of interpretation – based on the ‘whole clinical picture’ and on the information on a specific patient – is necessary and unavoidably a part of the clinical assessment of every patient, scale items that are not subject to interpretation should be preferred as they are more likely to produce objective outcomes.Regarding the postoperative scores, irrespective of the assessor, these tended to be skewed towards the lower end of each scale range, indicating an overall good level Figure 1 Preoperative and postoperative scores obtained with the Glasgow Feline Composite Measure Pain Scale (CMPS – Feline) by three independent assessors: A (board-certified veterinary anaesthetist), B (veterinary anaesthesia nurse) and C (final-year veterinary student). The boxes represent the second and third quartiles, with the horizontal line inside each box indicating the medians. The lower (25%) and upper (74%) quartiles are shown as vertical lines either side of each box. The dots represent the outliersFigure 3 Preoperative and postoperative scores obtained with the Feline Grimace Scale (FGS) by three independent assessors: A (board-certified veterinary anaesthetist), B (veterinary anaesthesia nurse) and C (final-year veterinary student). The boxes represent the second and third quartiles, with the horizontal line inside each box indicating the medians. The lower (25%) and upper (74%) quartiles are shown as vertical lines either side of each box. The dots represent the outliersFigure 2 Preoperative and postoperative scores obtained with the Colorado State University Feline Acute Pain Scale (CSU – FAPS) by three independent assessors: A (board-certified veterinary anaesthetist), B (veterinary anaesthesia nurse) and C (final-year veterinary student). The boxes represent the second and third quartiles, with the horizontal line inside each box indicating the medians. The lower (25%) and upper (74%) quartiles are shown as vertical lines either side of each box. The dots represent the outliersof postoperative analgesia. It is worth considering that the pain scales investigated in the current study may perform differently in the presence of a more severe degree of pain.6 Journal of Feline Medicine and Surgery The present study has some limitations. Although it was interesting and relevant to analyse the preoperative and postoperative scores both together and separately, it should be emphasised that, based on the sample size calculation, statistical tests performed on sub-groups of the study population may be underpowered and their results should be interpreted cautiously.Ideally, the order of the three scales should have been randomised for each assessment with either a simple randomisation method or a computer-based program. This would potentially have improved the methodology, considering that the results of the first assessment with one of the scales may have represented a source of bias for the subsequent evaluations performed by the same observer on the same cat. Regarding the order of the assessors, this could not be randomised owing to the need to adapt the study design to the clinical flow of a busy veterinary hospital. All cats underwent surgery and were discharged during working hours when the assessors were potentially busy with other clinical work and not necessarily available. Assessing the cats at different time points could have resulted in changes in the level of anal -gesia – and therefore of pain – in the cats. Therefore, the assessments were restricted to the same 30-min period; however, this resulted in a number of missed assessments due to the inability of some assessors to make themselves available when their evaluation was due.ConclusionsThe present study highlights that, despite their clinical usefulness to assess perioperative pain in feline patients, behavioural pain scales are limited by intrinsic subjectiv -ity. The users of these scales should bear in mind that the outcome may significantly vary depending on both the person performing the assessment and their personal interpretation of how to apply and use the scale.

Answer 49

In this retrospective study, intraoperative use of the anti-septic lavage solution did not decrease the incidence ofTPLO SSI. Instead, a higher number of SSIs were identi-fied in the dogs treated with antiseptic lavage comparedto traditionally used saline lavage. Due to these results,we rejected our hypothesis that dogs treated with antisep-tic lavage prior to TPLO wound closure would have acumulative SSI incidence of less than 5%. This was anunexpected finding given reports of the lavage reducingbioburden in human knee surgery.19–22However, theantiseptic lavage's efficacy in human patients has beenpredominantly described during revision procedures witha preexisting SSI rather than as a prophylactic therapy,and the antiseptic lavage is known to be effective, in part,due to its ability to disrupt biofilm, which may limit itsefficacy as a prophylactic treatment.24,25Biofilm-based infectious diseases represent up to 80%of all infectious diseases in human patients.21The extra-cellular polymeric substances (EPS) matrix in biofilmsTABLE 4 Analysis of variables predicted to be associated with surgical site infection for 1422 dogs that underwent tibial plateau levelingosteotomy procedure at one of six referral hospitals between 2019 and 2021.Variable EffectOdds ratio (OR), (95% CI) p-valueUnivariable Multivariable Univariable MultivariableGroup Antiseptic lavage vs. saline 1.8 (1.3 –2.5) 1.6 (1.03 –2.6) .001 .042Age at surgery Per 5 years 1.1 (0.9 –1.5) - .353 -Sex Female vs. female spayed 0.55 (0.17 –2.0) - .199 -Male vs. female spayed 2.5 (0.98 –5.7) - .199 -Male neutered vs. femalespayed1.0 (0.7 –1.5) - .199 -Male vs. female 0.22 (0.05 –1.0) - .199 -Female vs. male neutered 0.53 (0.16 –1.9) - .199 -Male vs. male neutered 2.4 (0.9 –5.5) - .199 -Breed - - - .233 -Single session procedure(s) Bilateral vs. unilateral TPLO 1.0 (0.5 –2.1) 2.5 (1.3 –4.5) .942 .004Surgeon - - - .001 .008Postoperative antibiotics Yes vs. No 0.5 (0.3 –0.8) - .008 -Additional procedures Yes vs. No 0.8 (0.5 –1.3) - .436 -Weight of dog Per 5 kg 1.0 (0.9 –1.04) 1.11 (1.05 –1.19) .486 .001Adhesive iodine drape used Yes vs. No 0.8 (0.5 –1.1) - .134 -Liposomal bupivacaineadministeredYes vs. No 0.6 (0.2 –2.2) - .376 -Abbreviations: CI, confidence interval; TPLO, tibial plateau leveling osteotomy.SANDERS ET AL . 171 1532950x, 2024, 1, creates a unique barrier that is resistant to most conven-tional antimicrobial treatments, protecting the bacteriainside. Normal antibiotics that target cell replicationcycles will be less effective because the bacteria areslower to proliferate inside the biofilm.21The nonantibio-tic, antiseptic lavage reduces the bioburden and bacterialcount by disrupting the biofilm to expose bacteria to anti-biotics, the body's normal defense systems, and removalvia lavage.21Specific mechanism of action for this prod-uct is thought to be from the acetic acid, having an anti-bacterial effect in its nondissociated form via damage toDNA and proteins via the disruption of proton gradientsnecessary to intracellular ATP production.22In a human study comparing antiseptic lavage andtheir efficacy against biofilms, this product was shown toeradicate planktonic bacteria after 1 min of exposure,while requiring 3 min of exposure to target mature bio-films.20It also had varied responses based on surface,being most effective against biofilms on porous titaniumimplants, and was shown to be more effective whenpulsed as a jet for mechanical disruption of the bio-film.20,21In our study, the antiseptic lavage was pooledfor 1 min instead of being administered under pressure,suggesting that results may change based on technique ofapplication, duration, and type of implant. While thestudy by Hunter et al. demonstrated reduced bioburdenand bacterial count within the surgical site after use ofsurgical lavage,21there was also initially increased cultur-able bacteria, supposedly because bacteria was liberatedfrom the biofilm.In a routine TPLO, there should not be an activeinfection to target, and the antiseptic lavage is utilized ina prophylactic manner for any sources of contaminationor break in sterile technique that occurred during the sur-gery. While this product may be effective at reducing bio-burden at the time of surgery, it does not have residualproperties to prevent future SSIs. Thus, a different resultmay be obtained if this product was used against activeSSIs such as when implants are being removed or duringtreatment of a deep SSI where implants are beingmaintained.The TPLO procedure has an increased risk of SSIcompared to other clean orthopedic procedures, thoughthe cause of this disparity is unknown and believed to bemultifactorial.2The finding that increasing weight of thedog correlates with increased risk of TPLO SSI is consis-tent with previous literature,1,3but the correlationbetween increased TPLO SSI risk and single session bilat-eral TPLO in this study's population contradicts findingsreported by Montano et al.26Since single session bilateralTPLO is not widely performed, it is possible that eitherthe surgeon(s) performing the single session bilateralTPLOs practiced in hospital settings with generallyhigher TPLO SSI rates, or the risk associated with differ-ent surgeons was increased due to the inherent risk ofTPLO SSI following single session bilateral TPLO. Fur-ther prospective studies may be indicated to determine ifthere is an increased risk of infection with single-sessionbilateral TPLOs.In this study, there was also a correlation between thesurgeon performing the TPLO and risk of TPLO SSI,though many variables relating to the surgeon were notassessed as outlined in the limitation section, limitingwhat conclusions can be extrapolated from this data.Antimicrobial stewardship protocols aim to limitTABLE 5 Bacterial culture results for cases with SSIsafter TPLO.Bacterium isolatedNumber ofcases ( n)Percentage(%)Methicillin-resistantStaphylococcuspseudintermedius26 16.56Methicillin-resistantStaphylococcus spp . (notMRSP)20 12.74Methicillin-resistant organism (not Staphylococcus)Xanthomonas spp. 1 0.64Pseudomonas spp. 3 1.91Streptococci spp. 1 0.64Enterococcus spp. 2 1.27Escherichia coli 1 0.64Staphylococcus spp. 20 12.74Streptococcus spp. 7 4.46Enterococcus spp. 4 2.55Pseudomonas spp. 3 1.91Bacillus spp. 1 0.64Klebsiella spp. 1 0.64Nocardia spp. 1 0.64Pasteurella spp. 1 0.64Escherichia coli 1 0.64Staphylococcus/E. coli/Enterococcus spp.a1 0.64Not available for review 3 1.91No culture submitted 38 24.20No growth 22 14.01Total 157Abbreviations: SSIs, surgical site infections; TPLO, tibial plateau levelingosteotomy.aIsolated from the same SSI.172 SANDERS ET AL . 1532950x, 2024, 1, inappropriate use of antibiotics while promoting optimaloutcomes for patients. Routine, prophylactic postopera-tive antibiotic use poses a “one health ”challenge byincreasing the risk of development of multidrug resistantbacteria.1,2,9Unfortunately, the impact of routine, pro-phylactic antibiotic prescription on TPLO SSI is ambigu-ous and conflicting in the veterinary literature with theuse of prophylactic antibiotics being reported to lowerTPLO SSI risk1–3,5,6,9,10,12 –17and have no effect on TPLOSSI risk.1,2,14,17Due to these conflicting data and theimportance of antimicrobial stewardship, alternativeantimicrobial practices are needed to reduce TPLO SSIrates. The antiseptic lavage reported in this study did notlower the incidence of SSI. There is a recent report of apovidone-iodine intraoperative lavage used in total hiparthroplasty that may serve as an additional avenue ofinvestigation for efficacy in lowering SSIs in TPLOs.27That lavage may be a more appropriate option for pro-phylactic therapy, and a study evaluating its efficacy inTPLO cases may present a nonantibiotic solution forreduction in TPLO SSIs.This study had several limitations. As a retrospectivestudy, the data gathered is reliant on the accuracy andcompleteness of medical records. Bias and confounderscannot be controlled due to a lack of randomization andmasking protocols, and therefore causality is difficult toimpossible to determine. To achieve an adequate samplesize, data were pooled from multiple institutions. Manyvariables cannot be standardized across different hospi-tals, such as surgeon differences (reports of breaks inaseptic technique, intraoperative contamination, tissuehandling style, glove type, implant selection, infectionreporting, potential carriers of MRSP), intraoperative andpostoperative TPLO protocol differences. Because thiswas a retrospective study involving multiple surgeons,there was no way to know what guided the decisionbehind which dogs received antiseptic lavage versussaline. While some surgeons may have utilized the anti-septic lavage in every case, others may have reserved itsuse for patients at higher risk of SSI, resulting in biastoward patient selection.Additionally, diagnosis of surgical site infection inthis study followed the guidelines of the CDC.23TheCDC's definition does not require a positive bacterial cul-ture for diagnosis of SSI if other specific factors, includinginflammation of the surgical wound site, are met. How-ever, clinician variability in interpretation of the CDCdefinition, especially when dogs are assessed by nonsur-geon clinicians, may have led to diagnosis of SSI in dogswithout a true TPLO SSI. However, most dogs suspectedof having TPLO SSI (75.8%) did receive culture and sensi-tivity testing performed by a veterinary diagnostic labora-tory and were diagnosed by a surgeon.In conclusion, the antiseptic lavage solution evaluatedin this study was ineffective at reducing TPLO SSIs; how-ever, a prospective, randomized evaluation of this prod-uct may further guide the efficacy of preclosure antisepticlavage in TPLO patients or in a population where biofilmis suspected. Due to the frequency of TPLO procedures,the increased SSI risk profile following TPLO, and thedetrimental one-health impacts of poor antimicrobialstewardship practices, further studies to identify effectivemethods of reducing TPLO SSI risk are warranted.AUTHOR CONTRIBUTIONSSanders BD, DVM: Provided contributions to the concep-tion and design of the work, acquisition, analysis, andinterpretation of data for the study; drafting and revisingthe work. Kruse MA, DVM, DACVS and McDonald-Lynch M, DVM, DACVS: Provided substantial contribu-tions to the study conception and design, data acquisitionand interpretation, critical manuscript revision, and finalapproval of the version to be published. All authors pro-vided a critical review of the manuscript and endorse thefinal version. All authors agree to be accountable for allaspects of the work as described by the ICMJE.ACKNOWLEDGMENTSThe authors thank Deborah Keys, PhD for her assistancein performing statistical analysis for this project and Ste-ven W. Frederick, LVT, VTS (Surgery) for his critical edi-torial work of the manuscript.CONFLICT OF INTEREST STATEMENTThe authors declare no conflict of interest related to thisreport.

Answer 50

Results of this study show no difference between treat-ment success, postoperative rescue opioid consumption,CMPS-SF pain scores, or %BW distin dogs receiving car-profen and single-dose surgical wound infiltration witheither LB or saline placebo, after TPLO. We could notreject our null hypotheses. It is possible that the lack oftreatment effect was due to a type II error, as the actualtreatment effect that we observed for %BWdistwas lowerthan our estimated value. Enrolling between 58 andTABLE 3 Success/failure analysisresults, where dogs requiring rescueanalgesia at any postoperativetimepoint (0 –48 h) were defined astreatment failures.LB (n=15) Saline placebo ( n=17) Chi square p-valueSuccess ( n) 13 12 .27Failure ( n)2 5Abbreviation: LB, liposomal bupivacaine.TABLE 4 Mean (standard deviation) for %BW distvalues for dogs receiving LB ( n=15) or saline placebo ( n=17).LB (n=15) Saline placebo ( n=17)Time %BW dist Number of dogs %BW dist Number of dogs p-valuePreoperative baseline 6.7 (4.0) 15 7.5 (4.7) 17 .61Time after extubation (h)4 3.9 (4.0) 13 1.6 (1.8) 12a.0812 2.9 (5.0) 13 1.8 (2.8) 12 .0724 3.3 (3.4) 13 2.4 (3.1) 12 .5048 2.4 (2.5) 11b4.8 (3.7) 12 .37Note: For dogs requiring rescue analgesia, concurrent and subsequent measurements of %BW distwere excluded from statistical analyses.Abbreviations: %BW dist, percent of total bodyweight distributed to the operated leg; LB, liposomal bupivacaine.aData point missing for one dog who was too sedated to stand but did not require rescue analgesia.bData points are missing for two dogs that refused to stand (in favor of sitting) on the weight distribution platform but did not require rescue analgesi a.726 ALDRICH ET AL . 1532950x, 2023, 5, 436 dogs into the study within a reasonable period wouldhave been very challenging.Using 46 and 28 dogs, respectively, two previous clini-cal studies25,27found that dogs administered LB were lesslikely to require rescue analgesia after stifle surgery. Thefirst was a randomized, placebo-controlled, masked pilotstudy of dogs undergoing lateral retinacular suture place-ment with arthrotomy. The percentage of dogs requiringrescue analgesia was significantly lower for dogs receiv-ing LB versus placebo over 0 –24, 0 –48, and 0 –72 h post-operative intervals.25Although the extent of the softtissue approach is similar between TPLO and lateral reti-nacular suture placement, TPLO involves greater surgicaltrauma. It is possible that periosteal and bone marrowpain are not well controlled by LB, especially if it doesnot penetrate deeper than the soft tissues into which it isinjected.A randomized, blinded study27incorporated carpro-fen into its postoperative analgesia protocol for dogs thatreceived either LB or 0.5% bupivacaine surgical site infil-tration for TPLO with arthrotomy. There was an opioid-sparing benefit of LB in the face of background treatmentwith carprofen. Over the 48 h postoperative period, dogsadministered LB at wound closure were less likely toneed rescue analgesia and received a lower amount ofpostoperative opioids.27This opioid-reducing effect wasattributed to the longer duration of effect of LB comparedwith standard bupivacaine. Although this study showed aclinical benefit of LB beyond that achieved by carprofenalone, we cannot directly compare their treatment suc-cess analysis with our own. The decision to provide res-cue analgesia in that study was based on pain scoresusing the CSU-CAPS, rather than the CMPS-SF. Theauthors argued27that CMPS-SF scores can be increasedby signs of anxiety in dogs. It is worth noting that whilethe LB pilot study used the CMPS-SF to identify patientsneeding rescue analgesia, the intervention level wasraised from a suggested 6/24 to 8/24 based on investigatorexperience.25Subjective pain scales are limited in their ability todescribe the magnitude of pain relief provided by thetreatment compared to placebo, but they are regarded asthe current gold standard for evaluating pain in ani-mals.42The original, longer form of the CMPS43has beenshown to have criterion validity, demonstrating sensitiv-ity to acute postoperative pain in dogs in a clinical set-ting.44While the CMPS-SF was derived from the CMPSto be more clinically applicable, it has not undergone cri-terion validation. In this and previous studies, back-ground analgesia has been minimized to improve thesensitivity of the CMPS-SF to treatment effect. Similar tofindings in the previous TPLO study,27pain scores in ourstudy were not different for dogs receiving LB comparedto control at any time point. The background effect of thecarprofen given to the dogs in these studies may haveobscured the ability to detect a clinical benefit of LB. Wecould have eliminated the background analgesic effect ofthe NSAID in the present study, but we considered itclinically valuable to determine whether LB might pro-vide detectable analgesia beyond that of carprofen.Another limitation of the study with respect to pain scor-ing was that we did not statistically test interobserveragreement between the two investigators during the pre-study training period.Objective means of pain assessment failed to demon-strate a difference in outcome for dogs receiving LB inboth the present study as well as a previous TPLOstudy.27In the previous study, mechanical nociceptivethreshold values did not differ between dogs that receivedLB compared with 0.5% bupivacaine. It is possible thatthe treatment effects of LB and standard bupivacainewere truly not different enough to be discriminated bypain scoring or pressure algometry. It is also possible thatindividual variability in responses to algometry45orlearned aversion to the algometer with repeated use27,46contributed to the insensitivity of the instrument to pain.Measurement of %BW distas a means of describinglimb use or presumed limb pain has been described inthe literature. Static bodyweight distribution was firstevaluated using pressure sensitive walkway equipment.In normal dogs, measurements of %BWdistwere consis-tent from 1 week to the next, provided handling tech-nique was consistent.29In dogs recovering from total hipreplacement, %BW distto the operated limb increased at3, 6, and 12 months after surgery, although it was notpossible to conclude whether this change was related to adecrease in limb pain over time or simply a change inlimb use. In another study, %BWdistwas shown to be assensitive as vertical impulse and peak vertical force forevaluating limb use in dogs before and months after totalhip replacement.31An acute pain model was assessedusing both static and dynamic measurements on a pres-sure sensitive walkway to compare a novel formulationof buprenorphine to placebo for the first 72 h followingstifle arthrotomy.47Regardless of treatment, %BW disttothe affected limb as well as peak vertical force (PVF) andvertical impulse (VI) were significantly decreased at allpostoperative assessments compared to baseline; how-ever, treatment with buprenorphine resulted in greater %BWdist, PVF and VI in the operated limb from 48 to 72 hwhen compared to placebo. It is possible that if dogs inthe present study continued to be assessed for an addi-tional 24 h, we may also have seen a difference in out-come between groups. However, prior studies evaluatingefficacy of LB, found improvement over placebo25orbupivacaine hydrochloride27within the first 48 h, so itALDRICH ET AL . 727 1532950x, 2023, 5, would also be expected to see a difference in efficacyprior to the 48 –72 h period in the present study.More recent research measuring %BW disthas madeuse of a weight distribution platform as an alternative topressure sensitive walkway equipment. Measurement of%BWdistusing a weight distribution platform was foundto be accurate compared to a pressure sensitivewalkway,32sensitive to, and specific for, limb lamenessand orthopedic disease,33and repeatable for pairedsame-day or next-day meas urements in dogs with hin-dlimb lameness.44In a prior study, CMPS-SF was mod-erately to strongly correlated to %BW distribution.48Inthat study, the treatment group was noted to scorehigher pain scores than the placebo group, so the corre-lation was the opposite of wh at was expected. We foundno linear correlation between these outcome measuresin the present study. This may be due to the fact that weobserved many dogs to offload the affected limb aftersurgery, and some continued to do so for the remainderof our study. It would be inaccurate to assume that alldogs who offload a limb during stance are equally pain-ful. Stance analysis may therefore be an insensitive mea-sure of pain in animals immediately after TPLO.Another limitation was the relatively infrequent post-operative measurement of %BWdist(4, 12, 24, and 48 h)compared with the frequency of pain scoring (2, 4, 8, 12,20, 24, 32, 40, and 48 h). In this way, we may have missedopportunities for %BW distto describe pain. Finally, insome dogs, we observed a preference for sitting or lyingdown on the weight distribution platform, which wasslightly elevated and softer than the surrounding floor.For these dogs, obtaining valid stance data requiredmany passes over the platform. This brings into questionthe practicality of using this equipment to measure %BWdist. Using a weight distribution platform that is lesstempting to dogs as a place of rest could make data col-lection more efficient.Finally, it is possible that LB may provide analgesicbenefits when combined with other medications not usedin this study. For instance, it is possible that LB may pro-vide benefits if combined with epidural analgesia or with afemoral-sciatic nerve block. However, this supposition can-not be determined without further experimental studies.We conclude that in this population of dogs recoveringfrom TPLO and receiving postoperative carprofen, therewas no difference between overall treatment success, rela-tive rescue analgesia requirement, CMPS-SF pain scores,or %BWdistin dogs that received surgical wound infiltra-tion with LB compared with saline placebo.AUTHOR CONTRIBUTIONSAldrich LA, DVM, MS, DA CVS-SA: Study conception,study design, acquisition and collation of raw data,writing and drafting of the work, critical revision andfinal approval of the manuscript, and agreement to beaccountable for all aspects of the work. Upchurch DA,DVM, MS, DACVS-SA: Study design, interpretation ofthe data, critical revision and final approval of the manu-script, and agreement to be accountable for all aspects ofthe work. Roush JK, DVM, MS, DA CVS: Statistical inter-pretation of data, critical revision and final approval ofthe manuscript, and agreement to be accountable for allaspects of the work.ACKNOWLEDGMENTSThe authors thank Iulia Osipova for help in the acquisi-tion and collation of raw data.FUNDING INFORMATIONSupported by an institutional grant from the Departmentof Clinical Sciences, College of Veterinary Medicine,Kansas State University.CONFLICT OF INTEREST STATEMENTThis manuscript represents a portion of a thesis submit-ted by Lauren A. Aldrich to the Kansas State UniversityGraduate Program as partial fulfillment of the require-ments for a Master of Science degree. The authors declareno conflict of interest related to this report.ORCIDDavid A. Upchurchhttps://orcid.org/0000-0001-7409-3957

Answer 51

Based on the literature search, this is the first study that describes the presence of the owners in the recovery period of dogs after surgical treatment of BOAS. The results from this study support our hypothesis that a calm and stress- free recovery assisted by the owner, followed by early discharge from the hospital is possible and safe. In addition, results from this cohort demonstrate that owner- assisted recovery from BOAS surgery may be useful to minimise morbidity, reduce the duration of hospitalisation and decrease the need for sedatives in the postoperative period com -pared to the standard recovery and hospitalisation.Recovery from anaesthesia is a critical period following airway surgery, particularly in brachycephalic dogs. Pain or fear- induced tachypnoea, together with the reduced thermoregulatory abil -ity, increase the work of breathing and can precipitate the cycle of oedema and inflammation in the upper respiratory tract after BOAS surgery (Poncet et al. 2005 , 2006 ). The progressive obstruction of the airway exacerbates the intraluminal negative Table 1. Age, gender and breed distributions across groupsOwner- assisted recoveryStandard recoveryn 42 21Age (months±sd) (P=0.28) 32 (±19) 26 (±21)Gender (P=0.21)Male 29 71% 14 66%Female 12 29% 7 34%Breed (P=0.83)English Bulldog 4 10% 3 14%French Bulldog 19 45% 11 52%Pug 17 40% 6 29%Others 2 5% 1 5%Table 2. Severity of respiratory and gastrointestinal clinical signs and stage of laryngeal collapse across groupsOwner- assisted recovery Standard recoveryRespiratory signs (P=0.37)1 4 10% 5 24%2 14 33% 8 38%3 24 57% 8 38%Gastrointestinal signs (P=0.49)1 21 50% 13 62%2 8 19% 2 9%3 13 31% 6 29%Laryngeal collapse (stage) (P=0.02)0 10 24% 8 38%1 15 35% 6 29%2 17 41% 4 19%3 0 0.0% 3 14%Table 3. Surgical techniques distribution across groupsOwner- assisted recoveryStandard recoveryStaphilectomy 1 2% 0 0%Folded Flap palatoplasty (P=1.0)41 98% 21 100%Rhinoplasty (P=1.0) 41 98% 20 95%Trader’s alaplasty and vestibuloplasty41 100% 18 90%Wedge resection alaplasty 0 0% 2 10%Tonsillectomy (P=0.271) 7 17% 6 29%Laryngeal sacculectomy (P=1.0)14 33% 7 33%Cuneiformectomy (P=1.0) 3 7% 1 5% 17485827, 2023, 11, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jsap.13647 by Vetagro Sup Aef, Wiley Online Library on [15/11/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseJ. J. Camarasa et al.Journal of Small Animal Practice • Vol 64 • November 2023 • © 2023 British Small Animal Veterinary Association. 684pressure and can lead to ineffective ventilation, hypoxia and respiratory arrest even after an apparently normal recovery from anaesthesia (Downing & Gibson 2018 , Lindsay et al. 2020 ).In our study, three dogs (14%) that underwent standard recovery developed respiratory distress that required reintuba -tion and temporary tracheostomy placement due to pharyngeal swelling and upper airway obstruction. This finding was in agree -ment with other studies that reported major complications rates between 6% and 16% (Fasanella et al. 2010 , Ree et al. 2016 , Hughes et al. 2018 , Lindsay et al. 2020 ). A recent study describ -ing management of postoperative respiratory complications in brachycephalic dogs, reported a significant relationship between vomiting and regurgitation following surgery and the incidence of respiratory complications (Lindsay et al. 2020 ). Of note, regurgitation or vomiting was not recorded during the time of hospitalisation in any of the dogs that suffered complications in the population reported here. Omeprazole and either maropi -tant or metoclopramide were consistently used in all cases in our study during the anaesthetic premedication and postoperative period, which may explain the lack of correlation between gas -trointestinal signs and postoperative complications in dogs that received standard recovery. It has been suggested that treatment with antacids, proton- pump inhibitors and anti- emetics pre and postoperatively may be beneficial to decrease the occurrence of gastroesophageal reflux and oesophagitis in dogs undergoing BOAS surgery (Poncet et al. 2006 , Downing & Gibson 2018 , Vangrinsven et al. 2021 ). Recent reports go further, and rec -ommend starting medical treatment 1 to 2 weeks before the surgery to decrease the incidence of gastrointestinal signs and possible aspiration pneumonia, which has also been established at our institution in the last years in addition to the previously described perioperative protocol (Costa et al. 2020 , Krainer & Dupré 2022 ).The three dogs that required temporary tracheostomy place -ment underwent laryngeal sacculectomy and one of those had unilateral cuneiformectomy performed. Despite both techniques being initially recommended as part of multilevel BOAS sur -gery, recent studies have debated their clinical benefit and have suggested that dogs undergoing laryngeal sacculectomy were more likely to develop severe complications in the immediate postoperative period, (Hughes et al. 2018 ). Although laryngeal sacculectomy and cuneiformectomy were not associated with tracheostomy tube placement in the present study, these results must be interpreted with caution since type II errors are likely to occur with small sample sizes.Three other dogs that remained hospitalised after standard anaesthesia recovery required several doses of acepromazine and oxygen supplementation to treat respiratory distress during hospitalisation, compared to none dogs enrolled in the owner- assisted perioperative protocol. Sedation in the postoperative period is necessary in some dogs to control the level of anxiety and reduce the respiratory rate in order to decrease air turbulence and improve airflow (Grubb 2010 , Downing & Gibson 2018 ). However, the anxiolytic effect of some drugs like acepromazine, which is commonly used to calm patients with airway disease, has not been demonstrated to date and some dogs may be refrac -tory requiring multiple doses or the addition of other sedative drugs (Riemer et al. 2021 ). Excessive sedation causes unnecessary relaxation of the pharyngeal muscle tone which may worsen the respiratory obstruction requiring reintubation and longer hos -pitalisation (Mosing 2016 , Murrell 2016 , Ellis & Leece 2017 , Downing & Gibson 2018 ). Since the use of these drugs is usually linked with other strategies such as active cooling and adrena -line nebulisation, specific information about the frequency of use of sedatives to manage respiratory distress after BOAS surgery is lacking in the literature. Owner- assisted recovery appears to be a valid option to reduce the stress level after airway surgery and reduce the use of sedative drugs allowing an earlier discharge from the hospital.Overall, the incidence of postoperative complications was lower (P=0.004) in dogs that underwent owner- assisted recovery and early discharge. None of these dogs experienced respiratory distress requiring sedation or advanced interventions during the time of hospitalisation. This result confirms our hypothesis that implementation of the new recovery protocol would be safe and would not increase the respiratory morbidity after BOAS surgery compared with the traditional recovery and hospitalisation. It has been proven that the presence of the owner with the dog in a hospital setting can affect the behaviour of the animal, especially in a stressful situation (Rehn & Keeling 2016 , Lind et al. 2017 ). Although not analysed in our study, cortisol levels, oxidative stress markers as well as heart rate and blood pressure values decrease when owners administer calm, tactile stimulation; those levels appeared increased during hospitalisation in the absence of the owners (Siracusa et al. 2008 , Handlin et al. 2012 , Höglund et al. 2012 , Juodžentė et al. 2018 ). Other chemicals and hor -mones like β- endorphin, oxytocin, prolactin and dopamine also appeared elevated after positive human– dog interactions such as petting (Odendaal & Meintjes 2003 , Nagasawa et al. 2009 ). The influence of owner- recovery in the aforementioned stress markers in brachycephalic dogs undertaking upper airway surgery war -rants further investigations and is yet to be established.Owner- assisted recovery requires the personal commitment of the owners to spend several hours with their animal in a hos -pital setting. Yet, owners of brachycephalic dogs are known to build strong emotional bonds with their pets in a similar way to those with children and therefore may show a higher predisposi -tion to actively participate in the treatment of their pet (Sandøe et al. 2017 , Packer et al. 2019 ). Since stress contagion has been reported to synchronise between dogs and humans, client edu -cation and owner’s perceptions at the time of consultation are critical before adopting this recovery protocol in an individual patient to warrant a positive outcome (Sundman et al. 2019 ).In addition to reducing the stress and postoperative dyspnoea, early hospital discharge after airway surgery has been established at the authors’ institution since 2018 and it is also common prac -tice in other veterinary referral centres (Holloway et al. 2022 , Krainer & Dupré 2022 ). A recent study published by Holloway et al. (2022 ) describing the split staphylectomy technique reported good outcomes in dogs discharged on the same day of the pro -cedure. No urgent interventions between hospital discharge and the scheduled postoperative reassessment were related to a life- 17485827, 2023, 11, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jsap.13647 by Vetagro Sup Aef, Wiley Online Library on [15/11/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseOwner- assisted recovery after BOAS surgeryJournal of Small Animal Practice • Vol 64 • November 2023 • © 2023 British Small Animal Veterinary Association. 685 threatening respiratory condition (Holloway et al. 2022 ). Our results are equally positive given that none of the dogs in this cohort were presented to the hospital or to the primary veterinary practice in the 24 hours following discharge to receive treatment related to postoperative complications. In the authors’ experi -ence, early discharge from the hospital is a safe and valid option to decrease the stress of hospitalisation which unquestionably can lead to deterioration after surgery. This argument is contrary to the traditional approach that advocates at least 24 hours of observation in the hospital before discharge because complica -tions can occur late after the surgical procedure (Dunié- Mérigot et al. 2010 , Fenner et al. 2020 , Lindsay et al. 2020 ). However, it is difficult to recognise with exactitude the specific cause and time when complications occur due to the retrospective nature of most of the published studies. Ultimately, the decision to dis -charge the animal needs to be subject to the clinician’s assessment of the patient and must be tailored to every individual case.The limitations of this study are reflected in its retrospective nature and the lack of randomisation between groups. Instead, all dogs in the initial period of study underwent traditional recov -ery whilst all dogs in the latter period underwent owner- assisted recovery and early discharge and several factors might have caused potential bias in the outcomes. In addition, different breeds are known to have diverse anatomical variations and disease com -ponents. Although no significant differences were encountered between groups in the proportion of breeds, the severity of gastro -intestinal or respiratory signs and surgical techniques employed, subjective evaluation of the clinical signs and anatomic abnormali -ties may lead to errors on the classification. It should be also noted that the percentage of dogs with severe laryngeal collapse was higher in dogs that underwent standard recovery. However, the stage of laryngeal collapse as a prognostic indicator in BOAS sur -gery is controversial and there appears to be a lack of correlation with the overall postoperative prognosis (Torrez & Hunt 2006 , Haimel & Dupré 2015 , Liu et al. 2017 ). A randomised, blinded, prospective study with a larger population comparing the two different postoperative protocols would be necessary to further explore the benefits of owner- assisted recovery and early discharge.The recovery and postoperative period in dogs with BOAS is critical to minimise complications. A proactive approach to mini -mising stress aids in avoiding a cycle of airway oedema and altered airflow causing dynamic collapse, which ultimately can lead to life- threatening pulmonary oedema. A calm recovery assisted by the owner together with early hospital discharge can reduce the extent of the stress response in a hospital setting situation and may decrease the incidence of postoperative complications after BOAS surgery.AcknowledgementsThe authors would like to thank M. Jiménez- Pelaéz, DVM, DipECVS, MRCVS, for his invaluable advice in the conception of this study.Author contributionsJuan Jose Camarasa: Conceptualization (equal); data curation (lead); formal analysis (lead); investigation (equal); methodology (equal); project administration (equal); resources (equal); vali -dation (lead); writing – original draft (lead). Ines Gordo: Data curation (equal); formal analysis (equal); investigation (equal); methodology (equal); supervision (equal); validation (equal). Frances G. Bird: Data curation (equal); formal analysis (equal); investigation (equal); methodology (equal); supervision (equal); validation (equal); writing – review and editing (equal). Rosa -rio Vallefuoco: Data curation (equal); formal analysis (equal); investigation (equal); methodology (equal); supervision (equal); validation (equal). Mark Longley: Data curation (equal); for -mal analysis (equal); investigation (equal); methodology (equal); supervision (equal); validation (equal). Herve N. Brissot: Conceptualization (lead); data curation (equal); formal analy -sis (equal); investigation (equal); methodology (equal); project administration (lead); supervision (lead); validation (equal); writ -ing – review and editing (lead).Conflict of interestNone of the authors of this article has a financial or personal relationship with other people or organisations that could inap -propriately influence or bias the content of the paper.

Answer 52

The results of this study indicated that S and FFP surger-ies had similar anesthetic, minor, and major complica-tions, as well as similar hospitalization duration.Variation in the prevalence of select pre-, intra-, and post-operative results existed between soft palate surgerytypes; however, dogs undergoing FFP were associatedwith longer operative and anesthetic times when evaluat-ing time without concurrent non-airway procedures.Fourteen different breeds underwent surgical repairfor an elongated soft palate. In this study, the FrenchBulldog, English Bulldog, and Pug were the most com-mon breeds undergoing soft palate surgery. Our studypopulation was comparable to previously evaluatedBOAS populations.2–4,6,8 –13A low prevalence of clinical signs among dogs under-going soft palate surgery was reported, suggesting manyof these procedures were performed preventatively. Aprevious study reports that respiratory obstruction can befurther exacerbated due to nasopharyngeal and oropha-ryngeal obstruction as a result of thicker soft palates andnot just due to elongated soft palates.8In addition, a two-way influential relationship between upper respiratorytract disease and gastroesophageal disease has beenreported.5,14Furthermore, upper airway obstruction canworsen the intrathoracic pressure thereby increasing therisk of reflux and herniation.11,15,16Regurgitation, vomit-ing, and reflux can also worsen respiratory signs by nega-tively affecting the pharyngeal region and stimulatingfurther inflammation.5Therefore, it is possible that dogswith more secondary GI signs were appreciated to havethicker soft palates and were more likely to undergo aFFP to address both the length and thickness of the softpalate; however, soft palate thickness was not noted onairway examination findings, so this was not able to beevaluated. A prospective study comparing clinical signsand soft palate imaging could provide further insight.Over the years of this study's records, soft palate sur-geries increased and may be a result of increased brachy-cephalic breed prevalence in the canine pet population.In addition, the distribution of soft palate surgery typeschanged with increasing use of FFPs in later years. Thismay be a result of increased popularity of a new tech-nique or due to surgeon experience and change in proce-dure preference. In this study, some surgeons performedmore of one soft palate surgery type; however, it cannotbe determined from records if this was based on dogselection or surgeon preference. Surgeons may have usedcervical radiographs to assess soft palate thickness; how-ever, this was not documented and may not haveoccurred with every dog because some surgeons may pre-fer one procedure regardless of palate thickness.A previous study suggests that /C2475% of total airwayresistance originates within the nares and that more dogswith obstructed nasal cavities were more likely ( /C2470%) toalso have concurrent soft palate and laryngeal sacculeabnormalities.4Further studies evaluated the prevalenceof stenotic nares ranging from 51 to 100%, with higherpercentages in newer studies.2,5,6,9,11,17 –19This is similarto our study where /C2485% of dogs undergoing soft palatesurgery had evidence of stenotic nares. Among dogs alsoundergoing nares correction surgery, certain techniqueswere more commonly performed with a specific soft pal-ate surgery. However, surgeon preference for both theMILLER ET AL . 35 1532950x, 2024, 1, type of soft palate surgery and nares surgery could haveinfluenced this.A previous study found that brachycephalic dogs wereat a greater risk of anesthetic-related complications thannon-brachycephalic dogs (1.57 times more likely), partic-ularly with increasing anesthetic times.1Another studyalso found a 12% increased odds of complications post-anesthesia and a 11% increased odds of complicationsduring anesthesia when anesthetic time increased by anextra 15 min.20In our study, FFP had longer mediananesthetic and operative times than staphylectomieswithout concurrent non-airway procedures. However, incontrast to the aforementioned study, longer anestheticand surgical times did not appear to cause more signifi-cant anesthetic complications in FFP dogs in this study.This may suggest that although brachycephalic dogs maybe at higher risk for anesthetic complications during sur-gery, FFP dogs may not be more likely to have complica-tions than S dogs. Further prospective studies evaluatingthis relationship are recommended.In a previous study, upper airway surgery wasreported to be commonly associated with postoperativecomplications.7Dyspnea was the most common compli-cation reported, but others included coughing, infection/inflammation, vomiting, regurgitation, and cyanosis.7Furthermore, another study found that brachycephalicdogs were at much higher risk for developing postopera-tive complications than non-brachycephalic dogs.1Within the postoperative period of our study, medianduration of hospitalization did not differ and minor andmajor complications were similar across both soft palatesurgeries. Therefore, even though FFP surgeries arereportedly more technically challenging with more softtissue dissection and longer surgical times than S surger-ies, they did not require more postoperative support thanS dogs.8Based on the possibility of additional perceivedairway swelling postoperatively with FFP dogs, differentclinicians may have tried to provide more postoperativesupport in the form of oxygen and different medicationsin-hospital and for discharge; however, this was found tobe inconsistent among soft palate surgeries in our currentstudy. This is likely the result of surgeon's preference ofpostoperative care. Duration of oxygen supplementationmay also vary depending on when technical staff can dis-continue it. Further prospective studies looking at the useof anti-inflammatory, prokinetic, antiemetic, and GI pro-tectant use may provide more information on the benefitor prognosis of either soft palate surgery in the postopera-tive period.The prevalence of persistent clinical signs during thepostoperative and follow-up periods decreased for allsigns except regurgitation, where one additional dogexperienced regurgitation postoperatively compared tothe preoperative period. Given the small number of dogswith persistent signs, comparison of individual clinicalsigns between soft palate surgeries is difficult; however,the overall decrease in clinical signs may suggest thateither soft palate surgery is sufficient in improving theresolution of both GI and respiratory signs. This is similarto other studies that found either a reduction or resolu-tion of 80 –100% of GI signs9,11and 88.3% of respiratorysigns among different brachycephalic breeds treatedsurgically.9It may also be that the appropriate surgicaltechnique (FFP vs. S) was chosen for each dog on a case-by-case basis based on surgeon assessment and experi-ence, such that a dog undergoing a FFP may not haverecovered as well postoperatively with a staphylectomy ifthere was concern for palate thickness; however, this wasnot able to be determined.Within the follow-up period, all dogs (3/3) with per-sistent hiatal hernias on preoperative and postoperativeimaging underwent FFP. In contrast, two other dogs thathad undergone S had evidence of a hiatal hernia on pre-operative imaging, but these hiatal hernias were notnoted on the dogs' postoperative imaging, which suggestsresolution of the hernia or a sliding hernia. However,nine dogs who had evidence of a hiatal hernia pre-operatively did not receive postoperative imaging andcorrelations cannot be made for these dogs. These find-ings related to hiatal hernias may be due to a type II errorand future research evaluating resolution of GI signs iswarranted. Because only seven dogs underwent arevision soft palate surgery, the need for any particularrevision BOAS surgery (i.e., S, FFP, nares, or laryngealsacculectomy revision) is difficult to assess between softpalate surgeries.The main limitation of this study was its retrospectivenature and the inability to randomize dogs in the studydesign. Data were obtained from medical records and oper-ative reports, requiring dependence on accurate reportingof laryngeal examination findings and accurate representa-tion of the intraoperative results. Soft palate thickness wasnot noted on pre-operative examination findings, so thisvariable was not evaluated; however, to objectively deter-mine whether S or FFP should be performed, soft palatethickness on CT should be measured. Another limitation ofthis study was individual clinician preference for surgicalprocedures and selection of treatments and medicationspostoperatively (in-hospital and for discharge). Sample sizeof some individual variables such as clinical signs, specificpre- and postoperative imaging results (i.e., hiatal herniasand hypoplastic tracheas), everted tonsils, tonsillectomies,and revision surgeries was small. Small sample size cancause a type II error and may influence our findings. Also,limited follow-up time with a large range reported in themedical record was a constraining factor. Further studies36 MILLER ET AL . 1532950x, 2024, 1, with power analysis and randomization to compare pre-,intra-, and postoperative variables in a prospective natureare recommended to provide better recommendations forsoft palate surgery selection.In conclusion, S and FFP had similar anestheticand perioperative complications, suggesting that both Sand FFP may be considered for treatment of an elongatedsoft palate as part of the BOAS, although FFP dogs hadlonger anesthetic and operative times.AUTHOR CONTRIBUTIONSMiller AK, DVM, MPH: Substantial contribution to the con-ception and design of this study, data acquisition, data anal-ysis, data interpretation, draf ting and revision of work, in-line specific manuscript editing, and final approval of man-uscript. Regier PJ, DVM, MS, DACVS-SA: Substantial con-tribution to the conception and design of this study, datainterpretation, revision of wor k, in-line specific manuscriptediting, and final approval of manuscript. Colee JC, MS:Statistician with substantial contribution to data analysis,data interpretation, in-line s pecific manuscript editingregarding statistical data, and f inal approval of manuscript.CONFLICT OF INTEREST STATEMENTThe authors declare no conflict of interest related to thisreport.ORCIDAnnellie K. Millerhttps://orcid.org/0000-0002-3844-0170

Answer 53

To the authors’ knowledge, this is the first large retrospective study to evaluate factors impacting owner decision-making regarding treatment of dogs presenting emergently with NTH. Additionally, this study assessed owner satisfaction with a chosen treatment and perceived QOL before, during, and after treatment. The 3 treatment options evaluated were euthanasia, palliative care, and surgery. The majority of patients were euthanized, consistent with previous studies2,3 on dogs with NTH. Patients more commonly received palliative care or were eu -thanized if initial workup revealed elevated lactate or imaging was highly suggestive of metastasis. Pa -tients undergoing surgery had significantly increased MST with greater perceived QOL and owner satisfac -tion compared with both palliative care and eutha -nasia. Although this survival benefit of surgery was lost when patients without malignant disease were excluded, several QOL scores remained improved.Owners reported QOL as the most important influence on decision-making, heavily or entirely impacting the treatment choice of > 90% of owners. Owners of dogs that underwent surgery reported significantly better QOL scores following treatment compared with those receiving palliative care, in -cluding increased appetite, comfort, and activity. After selecting for the subgroup of dogs with sur -gery and malignant disease, significantly higher ac -tivity and QOL scores on average and at the pet’s best were maintained as compared with scores for patients receiving palliative care. Given our findings, the apparent QOL advantage reported by owners of animals receiving surgery should be included in initial counseling, although these results are prone to recall and observer biases in this nonrandomized, nonblinded retrospective study design. While mul -tiple factors, including satisfaction and survival, in -fluence owners deciding between palliative care and surgery, our findings suggest that if QOL is identified as the main guiding concern in an owner’s selection, surgery should be highly considered.Following QOL, owners considered risk of can -cer and time remaining with their pet as the next most influential factors on treatment decision. Some prognostic indicators and diagnostic criteria, such as the hemangiosarcoma likelihood prediction (HeLP) score, have been recognized to prioritize neoplastic disease in patients with NTH.5–11,17 However, until a definitive diagnosis is able to be made prior to his -topathology, discussing the risk of common cancers and their associated prognoses in NTH cases is pru -dent. Many clinicians use the double two-thirds rule, which states two-thirds of splenic masses will be malignant and two-thirds of those will be hemangio -sarcoma, to counsel owners of pets presenting with NTH10,18; however, a recent study19 that evaluated the validity of this rule in dogs with NTH from a rup -tured splenic mass found more dogs were diagnosed with neoplasia (73.0%) and hemangiosarcoma spe -cifically (87.3%) than the double two-thirds rule indi -cates. Our data support this, with 75.6% of cases with histopathology classified as malignant and 83.9% of those malignant cases attributed to hemangiosar -coma.19 Owners should therefore be educated on the prevalence of malignant diagnoses and splenic hemangiosarcoma in particular, as these cases carry a poor prognosis, with an MST of < 3 months without adjuvant chemotherapy.18–22 Specifically, patients with malignant histopathology had an MST of 81 days in this study.Considering the reported influence of the risk of cancer on decision-making, caution must be exer -cised before recommending surgery in all cases. The most negative responses to the survey were from owners who felt they were not adequately advised on prognosis prior to pursuing surgery. When asked to describe why they would not make the same treat -ment decision again, these owners said, “poor prog -nosis for recovery after surgery … was not appropri -ately advised by medical staff, including the surgeon, prior to the surgery” and “the doctor gave us more hope than what should have been presented … had I been given a more honest answer about prognosis, I would have opted for humane euthanasia.” These responses underscore the need for standardized NTH discussions to improve client comprehension of treatment options and potential outcomes.Though a definitive diagnosis prior to tissue ac -quisition is not currently feasible, screening for me -tastasis through preoperative imaging may improve confidence in a malignant pathology and may be useful for an owner’s decision-making process. Our findings highlight that high suspicion of metastasis on imaging was negatively associated with survival, making surgery a less advantageous treatment ap -proach for owners most concerned with survivability of their pet. Out-of-hours staging may be warranted for owners who would euthanize their pet if metasta -sis were identified. Diagnostic modalities with higher sensitivity for metastasis may be beneficial for own -ers who are concerned about patient longevity. Stud -ies show CT may be able to detect early pulmonary Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 06/30/23 12:11 AM UTC JAVMA | JULY 2023 | VOL 261 | NO. 7 987and abdominal metastasis and discriminate between benign and malignant splenic lesions.20,23–25 These results highlight the need for nuanced discussions and appropriate preoperative staging prior to hospi -tal admission and treatment.While QOL and malignant potential were report -edly the most important factors influencing owner decision-making, other factors such as finances, co -morbidities, and pet age displayed modest impor -tance. These findings demonstrate that an individu -alized approach to owner counseling is necessary to solicit goals of care and priorities. Although not a discrete comorbidity, patients with elevated lactate on presentation were less likely to undergo any treat -ment, as well as surgery specifically; however, if taken to surgery, patients with elevated lactate preopera -tively were not negatively impacted with regard to long-term survival. This association may demonstrate a potential bias in how providers educate owners, and eventually treat their patients, when a dog presents with elevated lactate in the context of NTH.While a large majority of our sample reported confidence in their treatment choice and satisfac -tion with the related outcome, a smaller proportion of our respondents, about 20%, definitively second-guessed their treatment choice, and over 5% were unsure if they had second thoughts. Additionally, about 20% of owners were either extremely or some -what unsatisfied with the overall outcome of their treatment choice, while over 25% of owners report -ed a worse-than-expected patient outcome. These findings were not unique to any of the 3 treatment categories. Given the small proportion of our sample reporting these trends, we hope our study provides information to assist in informed decision-making of owners to promote confidence in treatment choices. To further mitigate owner dissatisfaction and sec -ond-guessing, incorporation of social workers into veterinary treatment teams has emerged as a prom -ising strategy to aid in client counseling, education, and follow-up communication.26,27The present study had several limitations. Own -ers responded to a retrospective survey sent by email, and data relied on owners’ ability to recall the factors impacting their treatment decision and satis -faction and emotions regarding that choice. Hence, the survey was prone to recall bias (follow-up times ranged from < 1 year to > 7 years) and nonrespon -dent bias. Further, the nonrandomized, nonblinded study design invoked a risk of observer bias, as own -ers who elected for surgery might have been more inclined to retroactively overestimate their pet’s QOL. Moreover, a validated veterinary QOL scoring system was not established in our study; therefore, owners were asked to rank their pet’s QOL on a 4-point Likert scale (1 = poor, 2 = fair, 3 = good, 4 = excellent). Differing interpretations of this subjective metric may have led to unreliability in QOL scores. Finally, through preoperative staging, a healthier group of individuals may have been selected for sur -gery, thereby skewing survival times.We report here the findings of the first large retrospective study of factors impacting owner decision-making regarding treatment of dogs pre -senting emergently with NTH, specifically assess -ing owner satisfaction and perceived QOL. Owners reported QOL as the most important influence on decision-making for NTH. Patients that underwent surgery had significantly increased MSTs with great -er perceived QOL and owner satisfaction compared with patients that underwent palliative care and eu -thanasia, suggesting that if these factors are iden -tified as most important to a client, surgery should be considered. Further, owners considered risk of cancer and time remaining with their pet as the next most influential factors impacting their treatment choice. We found that presumptive or confident di -agnosis of metastasis decreased survival times for all patients and that the survival benefit of surgery was lost when only those patients with confirmed malig -nant histopathology were analyzed. Therefore, we highly recommend preoperative staging and screen -ing for metastasis, especially for owners who person -ally view malignant disease as a contraindication for treatment. Regardless of treatment choice, about 25% of our respondents second-guessed their decision, which highlights the need for further educational and emotional support of clients during this difficult deci -sion. Ultimately, our findings strongly emphasize the need for standardization of NTH discussions of treat -ment options and potential outcomes, guided by fac -tors that are of greatest importance to an individual pet owner, to effectively and efficiently guide treat -ment of patients with this common presentation.AcknowledgmentsNo third-party funding or support was received in con -nection with this study or the writing or publication of the manuscript. The authors have nothing to declare.

Answer 54

Standard surgical approaches to intracranial lesions can becombined or modified to provide increased access to thebrain.9In veterinary medicine, standard methods exist forthe supratentorial regions of the cerebrum, the caudal dor-sal cerebellum, and the medulla.10For masses ventral tothe level of the zygomatic arch, achieving adequate expo-sure can be difficult.3,9The previously described ventralapproaches to the skull base, such as basioccipital craniect-omy10and transsphenoidal craniectomy,11are technicallychallenging and allow limited lateral exposure. Sturgesand Dickinson5described a dorsal midline approach, mod-ifying a rostrotentorial craniectomy with a partial zygo-matic ostectomy allowing access to lesions ventral to thecerebral convexity. However, this is a dorsal approach sothere is very limited access to the lesions within the caudalor medial to the piriform lobe. Shihab and colleagues uti-lized a mouth gag that moved the ramus of the mandibleto allow sufficient access to the temporal lobe to remove acavernous hemangioma without transection of the zygo-matic arch.12A suprazygomatical temporobasal approachwas also reported in a cat with temporal basal meningi-oma without removing the zygomatic arch.13Asada et al.described a ventrolateral temporal lobectomy in dogswhere they encountered a limited field of view due to asmall craniectomy window; the authors suggested thatamputation of the zygomatic arch would improve theapproach to temporal regions.14In human medicine, a zygomatic arch osteotomy hasbeen utilized to increase the rostral and inferior exposure ofthe pterional approach (fronto-temporo-sphenoidal craniot-omy) to allow broad access to difficult topographic areas,such as the middle fossa, the cavernous sinus, and thepetrous apex.15Zygomatic arch resections have also beenreported in sialoadenectomy16,17and lateral orbitotomy.18,19Although there are veterinary reports of zygomatic arch1188 CHEN ET AL . 1532950x, 2023, 8, resection in brain surgery, as far as the authors are aware,this is the only description of al a t e r a ls u r g i c a lt e c h n i q u ethat provides direct access to the middle fossa and the ros-tral brainstem.Three bones form the zygomatic arch. Rostrally, thezygomatic arch forms the ventral and lateral rim of theorbit. The central structure runs lateral to the ramus ofthe mandible and provides lateral contour to the face,and the caudal part serves as the origin for the massetermuscle.20In our technique, the zygomatic ostectomy/osteotomy site was limited to the area caudal to the fron-tal process of the zygomatic bone and immediately cra-nial to the coronoid process of the mandible. Thisapproach provided sufficient access to the sphenoid bone,avoiding disruption of the orbital rim or dysfunction ofthe mandibular condyles.15Magnetic resonance imagi ng-compatible titaniumsurgical implants are used in human medicine to securethe zygomatic arch fragment. In our cases, adequatecosmesis and stability were achieved without implants(Figure 2). The zygomatic arch fragment was notreplaced (case 1), secured by suturing the temporal fas-cia (case 2), or by suturing through the pre-drilled holesin the fragments and remaining zygomatic arch(case 3).Avoiding implants eliminated the risks of additionalanesthesia time, iatrogenic d amage to the facial nerves andmaxillary artery, and the cost of replacing the resected zygo-matic bone with an MRI-compatible implant. In small-breedbrachycephalic dogs or cats, where insufficient cosmesis orinstability was a concern, the fragment could be sutured intoplace as in case 3 or secured with a titanium locking platesystem,21each of which was MRI compatible.Access to the middle fossa requires rostral and dorsalmovement of the ramus of the mandible, which isachieved when the mouth is open. In case 1, a headframe(built by one of the authors) was secured to the maxillaand allowed the jaw to hang passively open, whereas incases 2 and 3, a headstand was used and required amouth gag. Though mouth gags have been identified as apotential risk factor for ischemic cortical blindness incats, there are no similar reports in dogs due to variationsin arterial blood supply to the brain.22While we did notdo this in our cadaver or clinical cases, we suspect thedorsal ramus can be removed to achieve an even greatersurgical window.19These techniques allowed easy anddirect access to the sphenoid and temporal bone and ade-quate visualization of the caudolateral aspect of the tem-poral lobe and mandibular nerve.The middle meningeal artery (MMA) runs on thecerebral surface between the petrous and squamous partsof the temporal bone.20Damaging this artery leads tointradural bleeding and compromised surgical visibility.To prevent intradural bleeding, the middle meningealartery is either skeletonized (isolated and retracted) orligated before durectomy. In theory, ligating the MMAmay result in visual disturbance or facial nerve paraly-sis.23However, in humans, MMA ligation and emboliza-tion have been used to treat hemorrhage and subduralhematoma, respectively; neither of these techniquescauses permanent damage to vision, the facial nerve, ortrigeminal nerve.24,25A combination of collateral arterialsupply and autoregulation in other meningeal arteries istheorized to prevents ischemic damage to the cerebralparenchyma and cranial nerves.20,22,26Both skeletoniza-tion and ligation of the MMA appear to be safe and effec-tive ways of preventing bleeding. In case 1 and case2, only minimal brain parenchyma retraction wasrequired to perform the incisional biopsy of the piriformlobe or debulking procedure. The key to this is the identi-fication of the upside-down “T”formed by the rostral andcaudal rhinal sulcus as it intersects with the pseudosyl-vian fissure. A slightly more caudal approach allows foridentifying a “U,”which outlines the caudal compositegyrus. These landmarks enable the surgeon to achievemaximal exposure without excessive skull removal ormanipulation of normal brain parenchyma. Asada andcolleagues published a preliminary study for ventrolateraltemporal lobectomy in dogs using similar landmarks togain access to the hippocampus and amygdala.14The minor differences among these three cases werebased on the mass locations and surgeon preferences forinstruments and techniques. All cases followed similaroperative approaches and successfully achieved thedesired exposure.Transient postoperative neur ological deficits are com-mon complications in canine brain surgery.1In case 1, therewas a miotic left pupil and an incomplete palpebral reflexon the left. The underlying cause of unilateral miosis mayhave been primary ocular disease (e.g., keratitis or iritis).Failed sympathetic innervatio nw a st h o u g h tl e s sl i k e l yd u eto a lack of associated ptosis and enophthalmos. An incom-plete palpebral reflex was noted for 2 and 12 weeks in twocases and was thought to be from surgical retraction of theauriculopalpebral nerve. The avoidance of transections orunnecessary retraction of the facial or trigeminal nerve isrecommended to reduce postoperative nerve dysfunction.In the postoperative period, monitoring for cornealerosion and using ocular lubricants are recommended. Inour cases, the postoperative neurological deficits weremild and self-resolving within 12 weeks, and all dogs hada good short-term outcome. The major limitation of thisreport is the small number of clinical cases. This surgicalapproach also does not allow sufficient access to struc-tures ventral to the temporomandibular joint, includingthe optic canal, orbital fissure, oval foramen, foramenlacerum, alar foramen, and external acoustic meatus.Despite these limitations, we conclude that the lateral,CHEN ET AL . 1189 1532950x, 2023, 8, transzygomatic approach can provide reasonable accessto middle fossa and rostral brainstem lesions in dogswithout major postoperative complications.ACKNOWLEDGMENTSAuthor Contributions: Chen S, BVM: Designed, illustratedand wrote the paper. Young MG, DVM, DACVIM: Contrib-uted to the design of the surgical technique and provided theclinical cases; helped to write the paper. Bush WW, VMD,DACVIM: Contributed to the design and helped write thepaper. Shores A, DVM, DACVIM: Contributed to the designof the surgical technique and provided the clinical cases.Levine C, DVM, DACVIM: Contributed to the design of thesurgical technique and provided the clinical cases.CONFLICT OF INTEREST STATEMENTThe authors declare no conflicts of interest related to thisreport.ORCIDSandy Chen https://orcid.org/0000-0002-2688-8197

Answer 55

Tube cystostomy provides a direct method of urinary diversion in dogs. The use of tube cystos -tomy for management of upper motor neuron blad -der secondary to IVDE or ischemic myelopathy has not previously been described. In this study, we discussed surgical approaches for cystostomy tube placement in female and male dogs following IVDE or ischemic myelopathy, duration of hospitalization following cystostomy tube placement, duration of cystostomy tube use, and complications associated with cystostomy tube use.The surgical approach for cystostomy tube place -ment in female dogs has previously been described. The reported surgical approaches for cystostomy tube placement in male dogs include a caudal midline celiotomy cranial to the prepuce or a grid approach in the inguinal region, which involves splitting the in -ternal abdominal oblique and transverse abdominus muscles.18 The surgical approach for cystostomy tube placement in male dogs as described in this study is simple and proposed as easy with low morbidity. The risk of complications was not higher for male dogs compared with females. For all dogs, it is important that cystopexy be performed during placement to en -sure secure apposition of the urinary bladder and the abdominal wall, thereby preventing uroabdomen in the event of inadvertent tube dislodgement.18Tube cystostomy offers numerous advantages over traditional techniques for management of upper motor neuron bladder in dogs with IVDE or ischemic myelopathy. In the current study, dogs were typically discharged the day after cystostomy tube placement (median, 1 day; range, 0 to 3 days), which facilitated ongoing nursing care at home. Urine drainage via the tube is a simple technique for owners to perform and requires minimal training. In the current study, 22 of 27 (81%) owners reported that the cystostomy tube was easy or very easy to use. In comparison, manual bladder expression is technically challenging and can be unproductive, as the external urethral sphincter re -mains closed.2 Effective manual expression is also dif -ficult if the dog is large, overweight, uncomfortable, or uncooperative. Urine drainage via tube cystostomy is not painful and does not require restraint.Tube cystostomy allows for extended urinary di -version for dogs with upper motor neuron bladder. The ability for dogs to consciously void following IVDE or ischemic myelopathy events typically occurs as voluntary motor function returns. In other words, conscious voiding typically occurs during the tran -sition from grade 4 to grade 3 using the MFS.15 No studies have evaluated the median time required for dogs with cervical or thoracolumbar IVDE or isch -emic myelopathy to improve from a grade 4 or 5 to a grade 3, or to regain the ability for conscious urina -tion. Aikawa et al19 reported a median time to am -bulation of 21 days for dogs with IVDE undergoing hemilaminectomy graded 5 at the time of presenta -tion. In the study reported here, the median duration of cystostomy tube use was 19 days, though the cys -tostomy tube was used for a maximum of 74 days. The longevity of tube cystostomy means it can be used for dogs where a protracted recovery time is expected (such as dogs with high-grade neurologic disease). Owners typically aspirated the cystostomy tube between 3 and 6 times daily (78%), though 20 27 (74%) owners reported a low or minimal daily time requirement, suggesting that cystostomy tube use is not a burdensome task.In comparison with indwelling urinary catheter -ization, tube cystostomy offers the unique advantage of allowing conscious urination to be assessed with -out removal of the tube. The urethra remains patent with tube cystostomy, allowing normal urine voiding. Dogs can be challenged to urinate by occluding the cystostomy tube and allowing the urinary bladder to fill to encourage normal urination. Residual volume following urination can be quantified to discern be -tween conscious voiding and overflow incontinence. Once consistent conscious voiding is reported, the cystostomy tube is removed. Treatment is therefore not unnecessarily protracted. Removal requires only cutting of the finger-trap suture and deflation of the cystostomy tube catheter bulb; the cystopexy pre -vents urine leakage into the abdomen, and the urinary bladder incision site heals quickly by second intention.In the current study, the median number of days from decompressive surgery to cystostomy tube placement was 4 (range, 0 to 12). Given the de -scribed benefits of tube cystostomy, we now advo -cate for placement of a cystostomy tube at the time of decompressive surgery for dogs that are unlikely to urinate consciously postoperatively (grade 4+). This obviates the need for a second anesthetic and surgery and reduces cost of additional hospitaliza -tion and surgery for the owner.In the current study, complications associated with tube cystostomy were reported in 21 of 56 dogs with follow-up data available (38%). This complication rate is consistent with previous studies13,18,20,21 report -ing use of tube cystostomy in dogs with various neu -rologic and obstructive urinary conditions, which re -ported a frequency of complications between 27% and 100%. Most complications (71%) were minor and re -Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 12/11/23 09:46 AM UTC6 solved with bedside intervention. The most frequent complication was inadvertent dislodgement of the cystostomy tube by the dog following discharge. All dogs in this study were discharged with an Elizabe -than collar, and the catheter was secured to the body using a stockinette. However, all cases of inadvertent dislodgement were caused by the dog chewing the tube cystostomy tubing. The reason for this is unclear though may include inappropriate Elizabethan collar size or poor owner compliance. Low-profile cystosto -my tubes have been described in multiple studies,13,20 with the primary reported benefit being reduced likelihood of inadvertent removal by the dog, as the device lies flush with the skin. However, cases of in -advertent removal by the dog have been documented using low-profile cystostomy tubes.20The second most frequent complication was peristomal urine leakage. This complication likely arises from an incomplete seal between the Foley catheter and the urinary bladder wall, as movement of the cystostomy tube through the stoma impedes formation of a seal. A small amount of leakage is manageable for the owners with dressing changes, and the cystopexy mitigates uroabdomen. Inser -tion of the cystostomy tube into the urinary bladder through a small cruciate stab incision can be facili -tated by using a stylet in the cystostomy tube.UTI is a sequelae of spinal cord injury in dogs, rather than the method of urinary outflow man -agement.1,22 As such, some degree of bacteriuria is expected in dogs following IVDE and ischemic my -elopathy.22 UTI was diagnosed in 10 of 25 dogs (40%) that did not require urinary outflow management following surgery for IVDE.6 In that study, UTI was confirmed with aerobic culture. UTI has also been documented in dogs following IVDE managed with all urinary outflow management techniques.3–5 The frequency of UTI with manual urinary bladder ex -pression and urethral catheterization ranges from 6% to 52%.3–5 Bubenik and Hosgood3 aimed to evaluate risk factors for UTI in dogs with IVDE that had man -ual urinary bladder expression, indwelling urethral catheterization, or intermittent urethral catheteriza -tion performed. In that study, 62 dogs were random -ly assigned to each treatment, and the investigators found that duration of treatment was the only risk factor for UTI, with each additional day of treatment increasing the risk of UTI by 1.5 times. A similar fre -quency of UTI is expected for dogs managed with tube cystostomy, as this technique does not obviate possible routes of infection. In the study reported here, urine culture was performed in 13 dogs. A positive aerobic culture was documented in 11 dogs (85% of dogs tested, 20% of dogs with follow-up data available). It is likely that the frequency of UTI was underreported, as urine microbial culture and sensi -tivity were not performed on all dogs; however, in our practice, urine is not routinely cultured without a high index of suspicion for overt UTI. Biofilms can form on urinary catheters regardless of the method of insertion, which can result in persistent UTI; as such, it is logical to screen for UTI once the cystos -tomy tube has been removed.23In the current study, the main proposed advan -tages of tube cystostomy centered around its effec -tiveness, durability, and ease of use. The major limi -tation of the current study is that different urinary outflow management techniques were not reported; therefore, we cannot conclude that tube cystostomy is superior to manual urinary bladder expression or urethral catheterization for urinary diversion in dogs with upper motor neuron bladder.This report details techniques for placement of cystostomy tubes in dogs with urinary bladder dys -function following IVDE or ischemic myelopathy cra -nial to the L3 spinal cord segment. The described surgical approaches are proposed as easy with low morbidity. Tube cystostomy facilitated early hos -pital discharge and extended, at-home manage -ment of dogs recovering from upper motor neuron urinary bladder dysfunction. Most owners reported that cystostomy tube use was easy and required low to minimal time commitment. Complications were frequent, though most complications were minor. Care to avoid inadvertent dislodgement by the dog is important, as this creates the most consequential complication, often requiring surgical replacement. Tube cystostomy can be considered for dogs with upper motor neuron bladder dysfunction secondary to IVDE or ischemic myelopathy, particularly when long-term urinary management is required.AcknowledgmentsNone reported.DisclosuresThe authors have nothing to disclose. No AI-assisted technologies were used in the generation of this manuscript.FundingThe authors have nothing to disclose.

Answer 56

Clinical opinion can be affected by a number of factors including confirmation bias, education back -ground, and access or exposure to different treat -ment options. The adage “if all you own is a hammer, everything looks like a nail,” may well apply here; VS are trained to resolve medical issues through the use of surgery, and RTh are trained in nonsurgical tech -niques. Rehabilitation certification does not require the same level of experience or education as board -ed specialty status. DB status requires the greatest level of education of all the reported groups, yet DB individuals may still have greater experience in one field over another. Given that VSMR specialization was only established in 2010, it may be that most DB individuals were already experienced surgeons with a surgical perspective before earning their boarded VSMR status.Survey response rate was not calculated as there was no accurate way to determine how many respon -dents were aware of the survey’s existence, nor could we ascertain how many eligible respondents there were. Even though absolute numbers of boarded surgeons or VSMRs were obtainable, no data exist to determine what percentage of these engage in prac -tice that treats biceps tendinopathy. Many surgeons do not perform orthopedics, focusing instead on soft tissue surgery. Similarly, many RTh work solely in the field of neurologic rehabilitation and do not practice sports medicine.There is a dearth of research on the effectiveness of various treatments for the multiple manifestations of biceps disease, and it will take considerable time to acquire evidence in the form of meta-analysis of prospective or retrospective clinical therapeutic tri -als. Until then, in the absence of such information and despite the above noted biases and limitations of clinical impressions, a consensus medical opinion based on the collective experience of qualified indi -viduals from a variety of backgrounds can be the first step in creating a framework on how to best treat BT disease. As new information becomes available, this framework can be modified to reflect such insights.As hypothesized, compared to RTh, VS attrib -uted less significance to the role of the BT in provid -ing shoulder stability; compared to the other groups, VS were significantly less likely to feel that the BT “always” contributes to shoulder stability and sig -nificantly more likely to feel it “never” contributes to shoulder stability.When asked whether “transecting the BT in -creases the chance of secondary shoulder region morbidities or degeneration long-term that will result in clinically relevant gait changes,” most respondents answered “don’t know” or “depends” on such factors as body weight or activity level of the dog. The least popular response was “always.” RTh were unanimous in agreeing that “never” was not the correct answer.In creating the 3 case scenarios, the aim of re -turning the patient to national-level competition was chosen because the authors felt that successfully achieving this goal would require a more complete resolution of the problem, compared to outcomes Table 6 —Use of modalities as part of CTx program, divided by group and averaged over all 3 cases. DB VS RT Total KWn 14 125 54 193 PRehab therapy 74% 72% 97% 79% < .0001Exercise restriction 57% 72% 88% 75% .01ESWT 74% 45% 81% 57% < .0001NSAID 60% 58% 33% 51% .01IL PRP 43% 40% 54% 44% .14PBM (laser) 33% 26% 72% 40% < .0001Non-NSAID Rx 33% 34% 43% 36% .47IA corticosteroids 36% 44% 8% 34% < .0001IA PRP 33% 25% 46% 32% .01Cage rest 29% 27% 11% 23% .05Therapeutic US 33% 14% 34% 21% < .0001IL MSC 10% 10% 23% 14% .01IL corticosteroids 7% 17% 4% 13% .03IA HA 14% 13% 9% 12% .26PEMF 10% 4% 29% 11% < .0001Other 0% 6% 25% 11% < .0001IA MSC 10% 8% 15% 10% .1IL HA 5% 3% 0% 2% .26External coaptation 0% 2% 1% 1% .88ESWT = Extracorporeal shockwave therapy. HA = Hyaluronic acid. IL = Intralesional. KW= Kruskal-Wallis multiple-comparison Z-value test (Dunn Test). MSC = Stem cell product. Non-NSAID Rx = Analgesic medications that are not NSAIDs. PBM = Photobi -omodulation. PEMF = Pulsed electromagnetic field therapy. PRP = Platelet-rich plasma. Rehab = Rehabilitation. US = Ultrasound. Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 01/27/24 05:24 PM UTC6 in which the patient would only be required to re -turn to a moderate level of exercise. The first case scenario was chosen to determine whether respon -dents would advocate transecting a healthy BT to palliatively address a primary supraspinatus lesion. Seventy-five percent tearing of the BT (Case 2) was selected to reflect a situation in which the authors suspected most respondents would consider the tendon unsalvageable. Twenty percent tearing of the BT (Case 3) was selected to reflect a situation in which the authors suspected most respondents would consider the tendon salvageable.As hypothesized, in choosing whether a surgical or CTx approach best addressed the 3 manifestations of bicipital tenosynovitis described in this survey, VS tended toward treating cases surgically and RTh did not. VS also tended to ascribe a worse prognosis for CTx compared to RTh. The opinion of DB individuals fell between these 2 groups.Despite these differences, there were areas of agreement as well. Specifically, 94.70% of respon -dents agreed that surgical transection of a healthy BT is an inappropriate first approach in addressing bicipital tenosynovitis secondary to supraspinatus impingement. This answer demonstrated the great -est consensus opinion of the entire survey. One po -tential reason for this broad consensus was that only 19.30% of respondents felt transecting the BT never contributes to the development of other shoulder comorbidities; for situations in which the supraspi -natus is already experiencing tendinopathy second -ary to repetitive stress, it could be argued that the loss of the BT’s shoulder stabilizing and extension functions would result in increased demand on the already compromised supraspinatus, thus worsening the pathology.When 20% of the BT is torn, 85.00% of respon -dents felt CTx is the best initial therapeutic ap -proach. Conversely, 68.30% of respondents agreed that surgery is the best initial approach in treating a BT that is 75% torn. Presumably, this shift in opinion reflected a belief that a 75% torn tendon is no lon -ger salvageable by CTx means. Respondents were not specifically asked at what point they feel a BT is no longer salvageable, and considerable research will be required to appropriately answer this ques -tion. Future research on CTx techniques for biceps repair should quantify the degree of BT fiber disrup -tion pretreatment so that more data can be gathered on this topic.This survey did not confirm the respondents’ therapeutic goals when attempting CTx: was the goal to reverse the tendon pathology and normalize the joint environment or simply to palliate the symptoms of pain? Such considerations may affect the choice of treatment. For example, 13% of respondents indicat -ed that they would perform intratendinous cortico -steroid injections, a technique that has been shown to cause tendon necrosis and subsequent rupture.16 For those who chose this modality, was the goal to palliate pain? Or, as 1 respondent indicated, was it to induce a complete rupture of the BT? The reliability of performing a bicipital tenotomy via intratendinous corticosteroid injection is unknown. However, it is similar in complexity and instrumentation to the in -cisionless technique of biceps tendon release, which has shown to provide reliable results in cadavers.12Intra-articular corticosteroid injection has fallen out of favor in human medicine because it is viewed as contraindicated for healing tendinopathy1,17 and the palliative benefits are both mild and transient.18 In contrast, seminal veterinary surgical textbooks con -tinue to recommend this therapeutic approach,19–21 yet VSMR textbooks make no such recommenda -tions.1 Such differences may underly why 8% of RTh recommended IA corticosteroid injections, com -pared to 44% of VS. Instead, IA PRP was used by 46% of RTh compared to 25% of VS. The palliative effect of PRP for arthritic pain is well documented,22,23 but its effectiveness in resolving BT pathology is unproven. Regenerative medicine is discussed as a treatment option for tendinopathy in at least 1 sports medicine textbook1 but not in surgery texts,19–21 potentially explaining the difference in popularity of PRP be -tween RTh and surgeons.We have no studies specifically looking at the use of PRP on the canine BT, but 1 study24 found a 40% response rate when used to treat supraspinatus tendinopathy. Similarly, bone marrow aspirate con -centrate coupled with PRP resolved 88% of supraspi -natus tendinopathy cases, with the remaining 12% showing incomplete improvement.25Thirty-three percent of RTh prescribed NSAIDs compared to 58% of VS. Respondents were not asked for how long they would prescribe NSAIDs, so it is unclear whether they intended long- or short-term use. In human medicine, the long-term use of NSAIDs is considered contraindicated when attempting to repair tendon damage, as there is little evidence that they help and there is concern that the vasoconstric -tive effect of NSAIDs inhibits the vasodilation re -quired for tendon healing.17Therapeutic exercise was the single most recom -mended CTx modality overall, with RTh significantly more likely to recommend it compared to VS (97% vs 72%). Cage rest was recommended by only 23% of respondents overall, with VS more likely to recom -mend cage rest compared to RTh (27% vs 11%), but this difference fell shy of statistical significance after post hoc analysis. A positive effect of therapeutic exercise on tendon repair has been shown in human research, as have the deleterious effects of inactiv -ity.26,27 Although cage rest may be required for pa -tient management in some situations, consideration should instead be given to pharmaceutic interven -tions such as trazadone and/or gabapentin. Staged return to normal exercise over several weeks, a main -stay of physiotherapy treatment in human medicine, should be employed.ESWT was the third most popular modality, se -lected by 57% of respondents. Leeman et al28 con -cluded that 85% of patients with some combination of biceps and supraspinatus tendinopathy experienced a good or excellent outcome on the basis of owner assessment following a treatment every 3 weeks for 3 treatments. Becker et al29 demonstrated long-term Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 01/27/24 05:24 PM UTC 7improvement in 64% of dogs following 3 treatments every 3 to 4 weeks, and Kern et al30 demonstrated improved ultrasonic appearance of both the supra -spinatus and biceps tendon following ESWT, in addi -tion to improved lameness scores.More recent meta-analytic research on the use of photobiomodulation for treating tendinopathy shows evidence of effectiveness, in contrast with ear -lier studies that did not.31–33 Conversely, therapeutic ultrasound was found to offer no benefit beyond the placebo effect,34 there is inconsistent evidence for the benefits of acupuncture,35 and PEMF has not been clinically evaluated for treating tendinopathy.36 Hyaluronic acid may play a role in the tendon heal -ing process and decrease adhesion formation.37,38 Manual therapy likely improves patient comfort and possibly mobility, but there is no evidence that it fa -cilitates tendon healing.39,40The above information, coupled with the limited canine research available, relevant human research, and what is known about tissue repair, was used to formulate the following recommendations for treat -ing biceps tendinopathy:• Surgery should not be the primary therapeutic approach when the BT is healthy or if the amount of fiber tearing is ≤ 20%. This recommendation is based on the unanimous consensus opinion of VS, RTh, and DB.• For situations in which the BT is 75% torn, surgery is likely the best initial therapeutic approach. CTx remains an option, but owners need to be informed of the guarded prognosis. This recom -mendation is based on the consensus opinion of VS and DB but a dissenting opinion from RTh.• For cases with tears between 20% and 75%, a case-by-case decision, ensuring best commu -nication about advantages and disadvantages with the owners is likely the best approach. This recommendation is based on the unanimous consensus opinion of VS, RTh, and DB that CTx is the best initial therapeutic response; however, there was disagreement between the 3 groups about whether a surgical prognosis exceeded that of CTx.• NSAIDs should only be used for short-term pain control and avoided completely when com -fort allows; protracted use may delay healing. NSAIDs are not indicated in chronic cases.• Intra-articular corticosteroids are not an appro -priate long-term conservative treatment and are contraindicated when the treatment goal in -cludes tissue repair.• Intratendinous corticosteroid injections must not be performed. If the end goal is tendon necrosis, a biceps tenotomy should be considered instead, using the least invasive approach available.• Injections of PRP might be useful, but there is cur -rently a lack of evidence in the published litera -ture when treating biceps tendinopathy in dogs.• Cage rest is discouraged unless required to en -force compliance with exercise restriction.• Consider multimodal CTx built on a foundation of therapeutic exercise combined with activity restriction that returns to normal in a staged man -ner over several months.• Modalities such as ESWT, regenerative medicine, and photobiomodulation should be considered.• At this time, there is insufficient evidence to rec -ommend therapeutic ultrasound, PEMF, or acu -puncture. Manual therapy may provide increased comfort but does not facilitate tendon repair.As new information becomes available, appro -priate adjustments should be made to the above recommendations. Each of these recommendations would benefit from future clinical research.AcknowledgmentsThe authors acknowledge Joe Hauptman.DisclosuresThe authors have nothing to disclose. No AI-assisted technologies were used in the generation of this manuscript.FundingThe authors have nothing to disclose.

Answer 57

This study was the first to examine the accuracy of a3DEP for MICVS decompression. Using postoperative CTand 3D modeling, the screw placement accuracy requiredto implant the 3DEP was evaluated. Screw angle andentry/exit point deviations were small. Postoperative 3Dmodeling revealed that in all specimens, ventral slotlength was less than a third of the vertebral body; slotwidth was less than half of the vertebral body. Lengths ofthe screws entering the spinal canal were less than0.5 mm as planned, except for 3 cases in which the lengthwas greater than 0.5 mm but less than 1 mm. The screwinstallation and ventral slot procedure using the 3DEPdid not differ between experienced and inexperiencedsurgeons. Taken together, these results suggested that useof a 3DEP for MICVS decompression was relatively easyand was applied correctly regardless of surgicalexperience.During the surgical approach for ventral slot decom-pression, it is important to avoid damage to major struc-tures such as the trachea, esophagus, jugular vein,carotid artery, recurrent laryngeal nerve, and vagosympa-thetic trunk. To perform the MISS approach for 3DEPinstallation, we produced custom dilators similar to thetubular retractor system. Using this method, sufficientworking space was achieved to install the 3DEP withoutusing a Gelpi retractor or instruments with sharp partsthat can cause fatal injury.During ventral slot decompression, when drilling isperformed with equipment tilted away from the midsagit-tal plane, the probability of damage that causes majorvenous sinus bleeding is 1.5%-25%.17In rare cases, thisbleeding can lead to life-threatening complications.8,17,18Using a surgical field view, it is also difficult to identifyaccurately whether slot width is less than half of the wid-est part of the vertebral body and slot length is less than athird of the length of each vertebral body. However, inthis study, if there was a subtle change in posture, the3DEP tilted with the animal, facilitating determination ofthe accurate drilling angle. This characteristic may pro-tect against drilling toward the venous sinus. Further-more, when using the 3DEP, ideal slot length and widthwere accurately planned using software, based on preop-erative CT images. Through postoperative 3D modelingusing a novel classification of slot decompression, slots ofdesired lengths and widths were created in all cases.Ventral slot decompression is a demanding surgicalprocedure that requires careful manipulation of the spi-nal cord and vascular structures because the surgical fieldis small, narrow, and deep. Illumination and magnifica-tion of the surgical field should be provided, so studieshave examined the use of video-assisted cervical ventralslot decompression in dogs.8,9,19,20A minimally invasiveventral slot study using an endoscope found that thetechnique could be easily applied to small and mediumdogs but was difficult to use in large- and giant-breeddogs.8The 3DEP compensated for this limitation becausean appropriate size can be manufactured and used forsurgery, based on unique individual bone sizes. Thecadavers used in this study weighed 3.1-34.4 kg. Previousstudies performed by the authors of this study using theexisting cannula and endoscopic system found that boneTABLE 1 Novel classification of slot decompression.Classification DescriptionType I(Figure 11B)The slot width is less than 50% of the widestpart of the vertebral body, and the slot iscreated while passing through the middle 2parts (b and c in Figure 11A).Type II(Figure 11C)The sloth width is less than 50% of the widestpart of the vertebral body; however, theslot is tilted and created while passingthrough the part of both ends (a or d inFigure 11A) of the 4 quarters of the widestpart of the vertebral body in the innercortex.Type III(Figure 11D)The slot width is less than 50% of the widestpart of the vertebral body; the slot is nottilted but is deviated and created whilepassing through the part of both ends (a ord in Figure 11A) of the 4 quarters of thewidest part of the vertebral body in theinner cortex.Type IV(Figure 11E)The slot width is greater than 50% of thewidest part of the vertebral body.KANG ET AL . 1167 1532950x, 2023, 8, debris generated during drilling could not be completelyremoved using suction; the debris and fluid also spreadinside the surgical field. It is therefore difficult to securethe visual field rapidly. However, because the 3DEP wascompressed by the bone, the fluid that included the bonedebris was removed using suctioning alone. The debrisdid not spread into the surrounding tissues, and it wasnot difficult to rapidly establish the visual field.In a previous MISS study using dilators and cannulas,instruments had to be repositioned if the muscles andsoft tissues invaded the visual field.21However, onceinstalled, the 3DEP does not require repositioningbecause it is fixed to the vertebral body in a position thatcoincides exactly with the bone surface. The surroundingsoft tissues or major structures therefore did not invadethe surgical field and visualization was unobstructed.Using this approach, it may be possible to reduce theprobability of iatrogenic damage and the installation timethat may be required during repositioning.This study had some limitations. First, the number ofcases was limited, and there was no control group.Further prospective comparative studies are needed toevaluate the benefits of our technique relative to the con-ventional ventral slot technique or other MISStechniques. Second, because 3DEP use requires a preop-erative CT for the guide design, additional anesthesia isrequired. Additional time and cost are also required todesign and produce the 3DEP. Due to the time delayrequired for guide design and production, use of thismethodology is therefore not suitable for animals requir-ing immediate spinal cord decompression. Third, learn-ing curves should be considered because the approachdiffers from the standard approach and unfamiliar instru-ments are used.5Fourth, printing, including object buildorientation and positioning, and postprocessing, includ-ing curing and sterilization, can modify the printedresin.22Fifth, because the MISS approach was performedalone by an experienced surgeon familiar with use of thedilators and cannula system, it was impossible to com-pare the overall surgical time objectively with an inexpe-rienced surgeon. Sixth, the implant was applied to thevertebrae using a bicortical screw. Although the preoper-ative planning was designed to allow the drill bit andscrew to penetrate only 0.5 mm into the spinal canal,TABLE 2 Deviations in the screw angle, entry point, and exit point and length of the screw entering the spinal canal for the experiencedsurgeon and inexperienced surgeon.Measurement Experienced surgeon ( n=15) Inexperienced surgeon ( n=15) pScrew angle deviation,/C142.178 ± 0.869 2.280 ± 0.796 .535Entry point deviation, mm 1.376 ± 0.636 1.478 ± 0.733 .836Exit point deviation, mm 1.514 ± 0.754 1.505 ± 0.883 .709Length of the screw enteringthe spinal canal, mm0.470 ± 0.087 0.560 ± 0.073 .312TABLE 3 Ventral slot length andwidth ratio for the experienced surgeonand inexperienced surgeon.Measurement Experienced surgeon Inexperienced surgeon pVentral slot length ratio, % 30.15 ± 1.86 29.38 ± 1.61 .372Ventral slot width ratio, % 45.60 ± 1.80 47.20 ± 1.54 .261FIGURE 12 Images of 3 cases that do not satisfy type I classification. (A-C) Although these 3 cases have slightly tilted slot formation,they are considered safe because they pass through the safe zone of the inner cortex.1168 KANG ET AL . 1532950x, 2023, 8, there was potential for damage to the spinal cord. Otherfixation methods should therefore be evaluated. Finally,because cadavers were used for this study, it was not pos-sible to evaluate the various conditions that may occur inlive dogs. Sinus bleeding and bleeding during drillingcannot be accurately evaluated in cadaveric dogs. Postop-erative nerve function and the potential for iatrogenicnerve damage also could not be assessed.In conclusion, use of the 3DEP for MICVS decom-pression can be considered an alternative to the standardventral slot procedure. Using the 3DEP, it was possible toperform spinal cord decompression effectively during theventral slot procedure with magnification and illumina-tion provided by an endoscope. Clinical studies areneeded to further evaluate the efficacy and safety of thistechnique.AUTHOR CONTRIBUTIONSJinsu Kang, DVM, PhD: Co-conceived study, performedsurgical procedures, interpreted the results, and preparedthe manuscript. Seungeon Lee, DVM, MS: Performedsurgical procedures and contributed to the interpretationof the data. Suyoung Heo, DVM, MS, PhD, CCRT: Co-conceived study and contributed to the interpretation ofthe data. Namsoo Kim, DVM, MS, PhD: Manuscriptpreparation and critical review of the article. All authorsapproved the final manuscript.ACKNOWLEDGMENTSThe authors would like to thank Seungyeol Lee, Myun-gryul Yang and Jaeeon Cheon of department of veteri-nary surgery, Jeonbuk National University for thier helpin the production of 3DEPs and the experiment.CONFLICT OF INTERESTThe authors declare no conflict of interest related to thisreport.ORCIDJinsu Kang https://orcid.org/0000-0001-5501-7983Suyoung Heo https://orcid.org/0000-0002-7733-3263Namsoo Kim https://orcid.org/0000-0003-2160-1203

Answer 58

The primary hypothesis, that the implementa -tion of a locking 3.5/4.0-mm jumbo TPLO plate in dogs > 50 kg would effectively prevent loss of reduc -tion resulting in a change in TPA, was rejected. This was based on the statistically significant increase in measured TPA (0.83° to 1.17°) during convales -cence measured by both observers. No intraopera -tive complications were recorded during the use of the aforementioned implant; however, a postopera -tive complication rate of 11 of 24 (45.8%), inclusive of 1 minor, 1 catastrophic, and 9 major complica -tions, was described. This led to rejection of a por -tion of the secondary hypothesis of comparable complication rates to the recent published literature on TPLO.4,14,15 In the face of high complication rates, a mean healing grade of 3.75 with a median of 4 was comparable to that published in the literature,14 pro-viding agreement to the portion of the hypothesis that bone healing scores would be comparable to the published literature on TPLO.A difference in calculated TPA at recheck follow -ing TPLO has previously been reported.9,10,21 Only a poster abstract13 has described the use of a single locking 3.5/4.0-mm jumbo TPLO plate for stabiliza -tion following TPLO, reporting no statistical change in TPA at 6-week postoperative follow-up. This is in contrast to the statistical increase in TPA of 0.83° to 1.17° depending on observer found in the present series. This implies secondary loss of reduction re -sulting in a change in TPA of the proximal tibial seg -ment throughout the convalescent period, entering into question whether the investigated implant pro -vides adequate stability in patients > 50 kg. Previ -ous investigations of the influence of various plating styles on TPA changes have shown that fixation using locking screws resulted in significantly less change in postoperative TPA when compared with nonlocking screws.21 Despite the use of a locking implant in this case series, secondary loss of reduction resulting in a change in TPA was described. An implant from a single manufacturer was used in all patients included in this study. Statistics from a previous publication22 discussing changes in TPA in dogs following TPLO indicate that implant type was the only variable as -sociated with changes in TPA postoperatively. It is possible that the use of a similarly large implant of a different design may prevent postoperative TPA change; however, this cannot be determined in the present report. In our cohort, 3.5-mm screws were Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 12/11/23 09:44 AM UTC6 used initially due to inability to source 4.0-mm screws in all screw lengths necessary to complete the pro -cedure for patients of this size. Due to the sample size of this cohort, the impact of screw size used on postoperative TPA change could not be evaluated. Further evaluation of screw size in prevention of sec -ondary loss of reduction resulting in a change in TPA is warranted in this patient population to ensure that the use of 3.5-mm screws in some patients did not influence the results in this study.The clinical significance of losing rotation during convalescence has not been rigorously investigated, nor has an acceptable change in TPA been reported. One report10 evaluating risk factors for postopera -tive tibial tuberosity fracture in TPLO patients shows that an increase in TPA over time was associated with tibial tuberosity fracture. No patients experienced tibial tuberosity fractures throughout the follow-up period of this study; however, this may be due to type II statistical error. The lack of tibial tuberosity frac -tures observed in our patients may also be explained by the decision to leave antirotational k-wires in situ, as a recent report23 outlined a 92% reduction in the risk of tibial tuberosity fractures when k-wires were left in situ compared with when they were removed at the time of surgery. A change in TPA is a second -ary loss of reduction, which indicates that instability at the osteotomy site is present and some degree of bone and/or implant failure has occurred. Despite a lack of significant evidence that changes in TPA are detrimental to the patient’s clinical status, stability of the osteotomy with minimization of interfragmentary strain is essential for direct bone healing to occur.24 Radiographic healing scores with a calculated mean and median of 3.75 and 4 respectively demonstrates high percentages of healing in the majority of pa -tients; however, grade 3 healing was described in 6 of 24 (25%) patients. This stratification in healing may partially be explained by the statistical increase in TPA calculated in this report. A secondary loss of reduc -tion implies an unstable environment for osteotomy healing, and a more stable environment may have in -creased the healing scores of our patient population.A postoperative complication rate of 11 of 24 (45.8%) was described in our report, leading to the rejection of a portion of the secondary hypothesis of comparable complication rates to the published lit -erature on TPLO.4,14,15 These previous reports within the recent literature display postoperative compli -cation rates of 5.4% to 11.4% (3/56 to 173/1,519); however, mean weights of the 3 cited studies var -ied from 35.7 to 37.3 kg and therefore were lower than the lightest patient within the cohort of this report.4,14,15 One of these cited studies4 displayed a correlation between increasing patient body weight and increased complication rates of TPLOs. The in -creased incidence of complications was described by an OR of 1.10 for every 4.5-kg increase in body weight. The literature on patient populations with similar patient weights in their inclusion criteria as the studied cohort reveals comparably higher complication rates of 18.4% to 27.8% (63/342 to 15/54).11,13,25 The reason for this increased rate of complication in heavier patients is unknown; how -ever, the statistically increased TPA during conva -lescence of 0.83° to 1.17° in our patient population displays movement at the level of the osteotomy. This indicates instability and that some degree of bone and/or implant failure has occurred, which may predispose to postoperative complications.A total perioperative SSI rate of 5 of 24 (20.8%) was recorded in this case series and is comparable to some other reports12,23,26 of similar cohorts. A prospective study8 comparing postoperative antibi -otic use with a placebo reported an OR of 1.047 to describe increasing risk of SSI for each kilogram in -crease in body weight. Using this reported value, one can calculate an increased risk of 193% when com -paring a 52-kg patient (the lightest patient from the studied cohort) with a 37.3-kg patient (the mean pa -tient weight from a cohort of 1,231 TPLO patients).4 Two retrospective studies5,6 also noted an increased risk of SSI with increasing body weight. One study,11 however, reported an SSI rate of 11.4% (39/342) in patients > 45 kg. In that report, 80% (274/342) of patients received postoperative antimicrobials in comparison with 37.5% (9/24) in the present study. It is unclear whether the different rates of postop -erative antimicrobial use are sufficient to account for the lower SSI rate, as studies attempting to evaluate this correlation have shown conflicting results.27 A retrospective study26 specific to patients > 50 kg re -vealed a lower incidence of SSI in patients receiving postoperative antibiotics. A prospective study evalu -ating the effect of postoperative antimicrobial use in giant-breed dogs following orthopedic surgery has not been performed to date and may be warranted to further investigate whether this particular popula -tion may benefit from their use. Despite the noted difference in antibiotic use, the SSI rate of 11.4% (39/342) in patients > 45 kg11 is more similar to the range of 2.9% to 11% (14/476 to 71/659) reported in the recent literature on complications following TPLO.5,7,15 These lower incidences of SSI should be considered the goal when developing and investigat -ing further implantation systems in giant breeds.Four complications encountered within the study period were TPLO implant removal for sus -pected latent implant infections. Culture and sensi -tivity were performed at the time of implant removal in all 4 cases; however, 2 cases had negative culture results. A recent publication28 evaluating risk factors and timing of deep SSI found an incidence of 3.0% (144/4,813) at a median of 279 days (49 to 2,394 days) postoperatively. This highlights the importance of including long-term follow-up following TPLO, as latent infections may develop many months to years following surgery. In acknowledgment of this state -ment, the present case series may underestimate the already high incidence (4/24 [16.7%]) of implant removal when using the locking jumbo 3.5/4.0-mm TPLO implant, as follow-up did not extend through the life span of all patients.Instability at the osteotomy site has been dis -cussed in association with SSI rate and implant-associated infection.26,29 This association has been Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 12/11/23 09:44 AM UTC 7implicated as a possible explanation for a difference in SSI rates when locking, and nonlocking plates are used following TPLO in dogs > 50 kg, as the use of nonlocking plates in the cited case series was sta -tistically associated with a higher incidence of infec -tion.26 Despite micromotion being discussed as a possible reason for resultant infection, little experi -mental data are available in the literature associating these 2 events. A recent experimental study30 in a murine femoral fracture model revealed that stable fixation allowed a higher proportion of 1 murine strain to clear an inoculation of Staphylococcus epi -dermidis in comparison with those mice of the same strain with an unstable fixation.30 This possible as -sociation is supported by the high SSI and implant removal rate noted in our patient population with concurrent statistical difference in TPA over conva -lescence; however, causation cannot be determined in this report.Despite high complication rates encountered within the present case series, owner-perceived out -comes were noted to be high, with the majority of respondents seeing their pet’s quality of life as ex -cellent and their pain severity and pain interference scores related to their surgical leg as low. While the overall low pain severity and interference scores col -lected on the postoperative CBPI are encouraging, it must be noted that no CBPI data were collected prior to surgery, preventing comparative analysis fol -lowing intervention. Canine Brief Pain Inventory data were obtained in extant patients due to the nature of the questionnaire reflecting current status of the pa -tient. While this avoided recall bias, the lack of CBPI data on deceased patients may introduce selection bias in the reported pain severity and pain interfer -ence scores. This is particularly evident because the patient experiencing a catastrophic complication of euthanasia was not included in CBPI data, which may have displayed comparatively very different values due to the patient’s condition at the time of eutha -nasia. The majority of respondents were very satis -fied with the outcome of the procedure and would consider the procedure again in the future. This satisfaction rate aligns with the majority of patients having no detectable lameness at final documented evaluation. The majority of complications encoun -tered from the procedure were SSIs, and nearly all resolved with medical or surgical treatment, which may explain the ultimate satisfaction and appropri -ate limb use encountered in follow-up.Limitations of the present study include the ret -rospective design, which relies on complete medical records and prevents procedural standardization. The retrospective nature additionally prevents standard -ization of medical management of patients postoper -atively, including how SSIs were managed. The small sample size limits the ability to thoroughly investigate the influence that various confounding factors may have on the outcome measures. These factors include, but are not limited to, varied histories, comorbidities, degrees of orthopedic disease, surgical techniques, and postoperative medication prescriptions. A further limitation is the lack of a case control group. Addition -ally, while a standard lameness scale was used to re -port lameness among patients, multiple observers of various experience levels documented lameness over time during recheck examination, which may intro -duce some inconsistency in lameness reporting be -tween patients and visits within the same patient. To truly investigate the influence a stabilization system has on outcome for dogs > 50 kg undergoing TPLO, a randomized controlled clinical trial would be nec -essary. Due to the infrequency in which giant-breed dogs are presented to this hospital for management of CCL disease, this would require a long collection period to accumulate adequate case numbers. Alter -natively, a multi-institutional study may be best to in -vestigate this question.In acknowledgment of the limitations outlined above, we conclude that the use of a locking 3.5/4.0-mm jumbo TPLO plate for canine patients > 50 kg undergoing a TPLO did not prevent secondary loss of reduction resulting in a change in TPA. Additionally, use of the aforementioned implant yielded unaccept -able postoperative outcomes in the described popu -lation when compared with the recent literature on postoperative outcome following TPLO. The majority of these complications were incisional in nature and resolved with appropriate medical or surgical man -agement. In the face of a high rate of complications and loss of reduction resulting in change in TPA post -operatively, comparable bone healing scores were described, and owner-perceived outcomes were high. Further investigation may include prospective cohort studies, studies utilizing gait analysis as an outcome measure, studies investigating the nature of incisional infections in giant-breed patients, and prospective studies comparing the outcomes of patients > 50 kg stabilized with various implantation systems and screw sizes.AcknowledgmentsThe authors would like to recognize Mr. Brady Henderson for volunteering his valuable time to aid in data collection.DisclosuresThe authors have nothing to disclose. No AI-assisted technologies were used in the generation of this manuscript.FundingThe authors have nothing to disclose.

Answer 59

In this study, we demonstrated that that techniqueaffected acceptable placement of pins in the canine thora-columbar spine, with the use of the 3DP technique result-ing in a higher proportion of safely placed pins.Ultimately, 87.5% and 69.8% of pins were graded asacceptable for the 3DP and FH groups, respectively. Fur-thermore, 64.6% of pins placed using the 3DP techniquereceived a grade of I, in comparison with only 48.3% forthe FH technique. In our study, the percentage of pinsthat were graded as acceptable for the 3DP group (87.5%)was similar to that of previous reports.40,42Oxley was thefirst to describe the use of patient-specific 3D-printed spi-nal implements in veterinary neurosurgery.43Since thattime, additional studies evaluating the utility of3D printing in canine spinal surgery have been pub-lished.39–42,44 –48Other groups using 3D printed drill guides in thethoracolumbar spine have reported similar findings tothe current study. Within these studies, the percentage ofpins receiving a rating of grade I on the modifiedZdichavsky classification (or considered acceptable basedon equivalent classifications) ranged from 79.3% to100%39,41,47,48,55In this study, 87.5% of pins were deter-mined to have acceptable placement, falling within thepreviously reported ranges. In the current study, onlyTABLE 3 Results of finalmultivariate logistic regression analysiswith outcome defined as pin placementbeing successful (grades I or IIa) or not(grades IIb, IIIa, or IIIb). Referencelevels are designated REF.Predictor variable Odds ratio 95% confidence interval pTechnique 3DPG REF n/a n/aFH 0.28 0.16, 0.47 <.0001Vertebra L1 REF n/a n/aL2 1.15 0.36, 3.75 .82L3 1.44 0.44, 4.96 .55L4 10.42 1.74, 200.35 .03L5 1.44 0.44, 4.96 .55L6 0.96 0.31, 3.02 .95T10 0.10 0.03, 0.28 <.0001T11 0.35 0.12, 0.96 .05T12 0.64 0.21, 1.86 .42T13 0.85 0.28, 2.59 .78Surgeon 1 REF n/a n/a2 9.61 2.79, 45.57 .0013 0.84 0.36, 1.92 .674 0.71 0.31, 1.60 .415 0.53 0.23, 1.19 .136 1.16 0.49, 2.80 .73Note:p-values in bold are significant.Abbreviations: 3DPG, three-dimensional patient-specific guide technique; FH, freehand technique.GUEVARA ET AL . 259 1532950x, 2024, 2, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14042 by Cochrane France, Wiley Online Library on [14/02/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License64.4% of pin placements were classified as grade I, whichis inconsistent with what was reported previously. Possi-ble explanations for the lower percentage of grade I clas-sification in the current study may be because theimplants were left in the spines for postoperative CT andgrading, compared to other studies in which implantswere removed before CT or only drill tracts weremade.47,55,56The presence of beam-hardening artifactsmay therefore have led to an overestimation of possiblecanal breaches. Another explanation may be related tothe fact that this study involved bilateral implant place-ment. Other studies have placed implants bilaterally;however, in some, the implants were removed or onlydrill tracts made,47,48decreasing the chance of having thefirst implant obstruct the placement of the second one.During placement of the second pin in the current study,if resistance was met, the implant trajectory was slightlyadjusted, potentially deviating from the premeasuredacceptable pin placement.A recent study by Mullins et al. was published com-paring pin placement accuracy using freehand probing or3D-printed drill guides.55Interestingly, this study foundthat both techniques resulted in similar accuracy for theplacement of spinal fixation pins, whereas the currentstudy found using 3D printed drill guides led to a higherproportion of acceptably placed pins. Reasons for this dif-ference may include the freehand technique used by Mul-lins et al. where a pedicle probing technique was appliedin which a cortical defect was created at the premeasuredscrew/pin entry point and the cancellous bone was thenprobed to determine a safe trajectory before drilling thepilot hole for pin/screw placement.55,57It is possible thatthe use of this probing technique leads to improvedimplant placement in comparison with other studiesusing different freehand techniques. All pins in this studywere also placed by a single, experienced surgeon, whichlikely influenced the accuracy. In our study, the surgeonwho created the 3DP drill guides was the most accurate(Surgeon 2). This individual has a great deal of experi-ence with cadaveric work and they were the individualwho was responsible for designing and manufacturingthe drill guides. It is therefore not surprising that theyoutperformed the other surgeons, despite their more lim-ited clinical experience.In addition to technique, vertebrae affected the oddsof successful pin placement, with both T10 and T11 hav-ing lower odds of success when compared with the L1reference. A possible explanation for this finding is theanatomical differences of the mid-to-high thoracic verte-brae, such as the limited amount of lamina compared tolumbar vertebrae, which can make implant placementmore challenging.52,53Implant placement in the caudalthoracic vertebrae is considered to be more difficultbecause it requires their placement in the vertebral bodythrough the pedicle, compared to the lumbar spine, inwhich implants are directly placed into the vertebralbody.41The thoracic vertebrae also have narrower bonecorridors, steeper corridor angles, and closer proximity tothe chest.48An additional challenge is the presence of theanticlinal vertebra (T10 –T12) at this level. Guides for T10were designed such that the base of the guide was con-toured to mirror the cranial and proximal aspects of thespinous process. All other guides (T11 –L6) were designedto contour the caudal and proximal aspects of theirrespective spinous processes. We suspect that this designdifference could have impacted the surgeons' comfortlevel while placing pins at the level of T10.The finding of lower odds of acceptable placement inT10 and T11 is quite different from the study by Marianiet al., in which implant placement in the T8 –T13 vertebrashowed 100% accuracy.47Reasons for the differencebetween the current study and the study by Mariani maybe largely based on differences in methodology. InMariani's study, although implant placement occurredbilaterally, only one implant was placed at a time andthen removed in comparison with the current study, inwhich implants were placed on both the left and rightside without removal. In a clinical setting, the placementof more than two implants per vertebrae is recom-mended.10,47However, in the thoracic spine, this can bequite challenging based on the vertebral size and theaforementioned risks. This might explain the lower suc-cess rate in our study. As discussed previously, theremoval of the implants and only assessing drill tractsmay have led to improved accuracy in the study by Mar-ian et al., as the effect of beam hardening was not pre-sent, and this was discussed as a limitation47Finally, the handedness of the surgeon may haveplayed a role in how well the pins were placed. The right-handed surgeon created drill tracts only on the left side,while the left-handed surgeon created drill tracts only onthe right.47In our study, all surgeons placed implantson both sides of the cadavers, regardless of handedness.Limiting the surgeon to only one side may therefore havealso influenced the results of Mariani's study.There were several limitations to this study. The pri-mary limitation was that a standard pin size was used forall cadavers. Although only medium- to large-breedcanine cadavers were used, differences in exact vertebralbody sizes may have led a given surgeon to select aslightly different implant size under clinical conditions.In the clinical setting, surgeons select pin size based onpreoperative measurements of pedicle thickness. It istherefore possible that using the same size pin for all ver-tebrae led to a higher percentage of canal breaches due tothe pin being too large. Similarly, the use of stainless-260 GUEVARA ET AL . 1532950x, 2024, 2, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14042 by Cochrane France, Wiley Online Library on [14/02/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensesteel pins led to a substantial beam-hardening artifact,which may have led to an overestimation of canal breach.However, CT was chosen as it has improved accuracy indetecting canal breaches compared to radiography.56,58The use of cadavers also limited our ability to assessthe vascular structures beneath the vertebral column,which could become compromised during pin placement.The design of the drill guides made the procedure some-what complicated. The drill guides did not allow theremoval of the drill bit after making the guide hole.The surgeon therefore had to drill the guide hole, removethe guide from the drill bit, reverse the drill out of theguide hole, and then replace the guide. As this was acadaver study, this was not an important issue but in aclinical setting the guide should be designed so the sur-geon could do every step without necessitating removalof the guide itself. Finally, the timing required to create3DP guides may not be realistic in emergent cases, suchas spinal fractures or luxations. Timing for productionreported in the literature ranges from 20 to 90 min.42,48,59However, a substantial learning curve may be associatedwith manufacturing drill guides, making the timing forproduction much longer.5|CONCLUSIONThe results of this study further demonstrate that 3DP isan effective alternative to conventional freehand verte-bral pin placement in canine cadavers, regardless of sur-geon experience as demonstrated by the high rate of pinsplaced acceptably. Further ex vivo and clinical studiesevaluating 3D-printed drill guides for veterinary spinalsurgery are warranted.AUTHOR CONTRIBUTIONSGuevara F, DVM, MS, DACVIM (Neurology): Study initi-ation and design, data collection, data analysis and inter-pretation, drafting of manuscript, approval of the finalversion of the manuscript. Foss KD, DVM, MS, DACVIM(Neurology): Study design, data analysis and interpreta-tion, manuscript revision, drafting of the initial manu-script and revisions, approval of the final version of themanuscript. Harper TAM, DVM, MS, DACVS-SA, CCRP,DACVSMR: Data collection, manuscript revision,approved the final version of the manuscript. Moran CA,DVM, MS, DACVS-SA: Data collection, manuscript revi-sion, approved the final version of the manuscript. HagueDW, DVM, DACVIM (Neurology): Data collection,manuscript revision, approved the final version of themanuscript. Hamel PES, DVM, MPH, DACVR: Data col-lection, manuscript revision, approved the final versionof the manuscript. Schaeffer DJ, PhD: Data analysis andinterpretation, approval of the final version of the manu-script. McCoy AM, DVM, MS, PhD, DACVS-LA: dataanalysis and interpretation, manuscript revision,approved the final version of the manuscript.ACKNOWLEDGMENTSThe authors would like to thank Melinda Smith andSusan Hartman for their assistance with the acquisitionof the computed tomographic images. They would alsolike to thank Ralf Moller, the director of technical ser-vices in mechanical science and engineering, for assis-tance and guidance for the 3D printing.FUNDING INFORMATIONThis study was funded by the University of Illinois Collegeof Veterinary Medicine Companion Animal ResearchGrant —The Dr. Allan and Mary Graham Fund.CONFLICT OF INTEREST STATEMENTThe authors declare no conflict of interest related to thisreport.ORCIDKari D. Fosshttps://orcid.org/0000-0002-9540-3093Devon W. Hague https://orcid.org/0000-0003-4511-272XDavid J. Schaeffer https://orcid.org/0000-0002-6040-052XAnnette M. McCoy https://orcid.org/0000-0003-4088-6902

Answer 60

Utilization of absorbable unidirectional barbed sutureswas not associated with leakage or dehiscence after gas-trointestinal surgery. In the long term, two dogs devel-oped an intestinal obstruction at the site of previousintestinal surgery, performed with an absorbable unidi-rectional barbed suture. In both cases, an enterectomywas required to correct the obstruction.The population of dogs and cats in this study is verysimilar to populations reported in other studies on gastro-intestinal surgery.3,6,10,32,33Age and sex distributions inthe population of this study are similar to other popula-tions of retrospective studies involving dogs.3,6,10,32,33Ourcat population is younger than the population describedby Hiebert et al.34In our study all cats had obstructionrelated to a foreign body. In contrast, Hiebert et al.34hada population with a wider range of indications for gastro-intestinal surgery. In similarity to other retrospectivestudies on gastrointestinal surgery in dogs, the most com-mon indication for gastrointestinal surgery in our popula-tion was an obstruction due to a foreign body.7,11,12,33,35None of the dogs in this study developed septic perito-nitis within the short-term follow up after surgery indicat-ing that leakage and dehiscence did not happen. Leakageand dehiscence are the two most common causes of septicperitonitis after gastrointestinal surgery, which will mostoften occur within the first 5 days after surgery. The rateof septic peritonitis after gastrointestinal surgery has beenreported between 2.0% and 16%.3,5–7,10–12,32,33,35,36The riskof dehiscence after intestinal surgery is greatest at 3 dayspostoperatively.37Jonsson et al.37further concluded thereto be 3 days of weakening followed by a fast rise instrength that terminates with complete intestinal strengthafter 14 days with minimal mechanical strength beingcontributed by the suture itself. The unidirectional barbedsuture used in this study was made of glycomer 631, whichloses 25% of its tensile strength at 14 days, and 60% after21 days postimplantation.2Hansen et al.26showed, in an ex vivo study, thatenterotomies completed with unidirectional barbedsutures leaked at a higher pressure than enterectomiesperformed with standard sutures. They hypothesized thatunidirectional sutures were able to maintain a betterapposition of tissue, which would explain the higherleakage pressure. Fealey et al.38did not show anincreased leakage pressure with unidirectional barbedsutures when resection and anastomoses were performedin the canine cadaveric intestine. Fealey et al.38andHansen et al.26utilized different suture manufacturerswhich may have contributed to the difference in theresults. Barbed sutures are built from regular monofila-ment sutures in which barbs are cut. Depending on thetechnique used to create the barbs, the barbs might be ofdifferent sizes and shapes resulting in larger suture holesthat could leak at lower pressure. Ehrhart et al.27evalu-ated the bursting strength of enterotomies and gastron-omies performed with unidirectional barbed sutures at3, 7, and 14 days after surgery in dogs. This study con-cluded that unidirectional barbed sutures were not asso-ciated with a reduction of bursting strength incomparison with standard sutures. There is therefore noevidence to suggest unidirectional barbed sutures nega-tively impacted healing potential during gastrointestinalsurgery in dogs.27The surgical site should heal beyondthe debridement phase, in a similar way to the healingthat occurs when standard sutures are used.27,31Unidirectional barbed sutures are not associated withan increased risk of fibrosis, adhesions, abscessation, orstenosis when used in gastrointestinal surgery.27,31How-ever, two of 18 dogs (11.1%) with long-term follow uppresented for return of clinical signs consistent withobstruction at days 20 and 27 postoperatively. One com-plication occurred at an enterotomy site, and the other atan enterectomy site. Both dogs required an enterectomyof the affected site. The histology of both sites was consis-tent with an inflammatory reaction, including leukocyteinfiltration into tissue and abscessation leading to lumi-nal narrowing. DePompeo et al.11reported the impactionof four of 87 (4.5%) surgical sites after using staplingequipment to perform an enterectomy months to yearsafter surgery. Intestinal-wall abscesses have beenreported at a rate of 5% and 3.3% in dogs and after usingstapling equipment, with abscessation developing withinthe first 5 days after surgery.14,39Ehrhart et al.27did notreport any signs of impaction or stenosis in their study indogs; however, only enterotomies were performed. Bau-tista et al.25did not report any stricture formation orimpaction in a series of gastrointestinal surgeries per-formed on 50 human patients with laparoscopic Roux-en-Y gastric bypass procedures. Unidirectional barbedsutures have the potential to affect the healing process bydecreasing blood supply to the edge of the tissue.18,19Vesicourethral anastomoses completed with unidirec-tional barbed sutures have been associated with anincreased amount of fibrosis and an increased risk ofurine leakage during the healing process, likely becausethe sutures were applied with too much tension, affectingblood flow.18,19It is therefore possible that the use of toomuch tension in those two dogs resulted in more inflam-mation at the surgical site and fibrosis. The barbs mayalso create some trauma to the wall of the intestine,inducing inflammation and fibrosis. However, one wouldexpect complications with leakage in the postoperativeperiod rather than fibrosis and stenosis 3 weeks after sur-gery. In the case of the enterectomy, the unidirectional1012 WILLIAMS and MONNET 1532950x, 2023, 7, barbed suture may have a purse-string effect, even whentwo strands are used, as the unidirectional barbed suturesdo not release tension after it advances and engages thetissue. Clapp et al.40reported 14 cases of small bowelobstruction after using unidirectional barbed sutures inhuman patients. The most common finding in these caseswas the loose tails of unidirectional barbed sutures caus-ing adhesions to other bowel serosa and mesentery, withsecondary volvulus in five cases. In this study, the loosetails of the suture were not a source of stricture at thesurgical site.This study has several limitations related to its retro-spective nature. As this is a descriptive study, no controlgroup was treated with standard monofilament sutures,and there is less control of confounding variablesbetween cases. A randomized clinical trial to compareunidirectional barbed sutures and standard monofila-ment sutures is now appropriate. The same board-certified surgeon performed the surgeries. This couldcreate selection bias as it is not a randomized selectionprocess. The surgeon performing gastrointestinal surgeryin these cases is very experienced with the use of barbedsutures. There were no dogs or cats with severe peritoni-tis at the time of surgery in this study, which is probablybiased in the case selection by the surgeon. Two caseshad mild septic peritonitis in this study. A prospectivestudy would better evaluate the impact of peritonitis onthe healing of gastrointestinal surgery performed withunidirectional barbed sutures. It was not possible to eval-uate risk factors for failure of the unidirectional barbedsuture as leakage and dehiscence did not occur in thisstudy. This would be better addressed in a randomizedclinical trial.Absorbable unidirectional barbed sutures can be usedto perform gastrointestinal surgery in dogs and cats. Itwas not associated with a risk of leakage or dehiscence inthis study. The development of obstruction at the previ-ous surgical site in 11.1% of dogs needs further investiga-tion to evaluate the role of the unidirectional barbedsuture in the development of impaction, stricture, orfibrosis.AUTHOR CONTRIBUTIONSWilliams EA, DVM: Author; primary study investigatorresponsible for acquisition, analysis, and interpretation ofdata. Monnet E, DVM, Ph.D., DACVS, DECVS: Author,primary surgeon in all cases, primary editor, mentor ofprofessional scientific writing.CONFLICT OF INTEREST STATEMENTThe authors declare no conflicts of interest related to thisreport. Sutures were used with no financial support from,or association with, the manufacturing company.ORCIDEvan A. Williams https://orcid.org/0000-0001-7378-5177Eric Monnet https://orcid.org/0000-0002-0058-2210

Answer 61

Based on the ﬁndings of our study, we failed to reject our nullhypothesis of no difference in incidence of postoperative SSIbetween the mediolateral and lateromedial direction ofplacement of the transcondylar screw for the surgical man-agement of canine humeral intracondylar ﬁssure.Several studies have been performed that only investi-gated the rate of SSI with mediolateral screw place-ment,4–6,10and these have reported infection rates of2/14, 1/34, 2/31 and 6/88 respectively. Possible explana-tions for the low SSI incidence in those studies includeplacement of transcondylar screws in lag/compression fash-ion,5,10the use of headless transcondylar screws,5the shortfollow-up time6,10and the use of a cannulated drill system.4Chase and colleagues3recorded 11/26 SSIs in a multicentrestudy of 26 lateromedial transcondylar screw (positionscrews). There are various other small studies, using alateromedial transcondylar screw that report a 0% SSI ratewith postoperative follow-up interval of between 4 weeksand 4.5 years.7,24–27The collective number of elbowstreated with a lateromedial transcondylar screw from allof these studies was only 20, of which 18 were placed in alag fashion.Spaniel breeds, Labradors and male dogs were overrepre-sented in our study and this is consistent with previouslydocumented ﬁndings.1,12The vascularity of the humeralcondyle in cases of humeral intracondylar ﬁssure in Spanielshas been shown to be abnormal,15and pre-existing crypticinfection has also been described.3It is possible that suchfactors could also contribute to the high rates of SSI afterhumeral intracondylar ﬁssure surgery. In addition, the factthat humeral intracondylar ﬁssures may not ossify28leads torepetitive loading and micromotion at the site of the ﬁssurewhich could predispose to later deep infection.Body weight1,11and placement of the transcondylarscrew in positional fashion have both been previouslyreported as precipitating factors for SSI following surgicalmanagement of humeral intracondylar ﬁssure.1Our resultssupport the ﬁnding that high body weight is statisticallycorrelated to SSI incidence. The retrospective nature of ourstudy did not allow body condition score to be tested, andthis might be a more representative variable in assessing theTable 2 Presentation of minor and major complications thatoccurred in each category (LM and ML) humeral intracondylarﬁssure transcondylar screws)LM screw ML screwMinor complicationsSeroma 5/15 4/31Major complicationsSSI: Culture positive 2/15 6/31SSI: Clinical/cytologicaldiagnosis only2/15 1/31Screw breakage 02 / 3 1Abbreviation: LM, lateromedial; ML, mediolateral; SSI, surgical siteinfection.Table 3 The logistic coef ﬁcient and the odds ratio for thestatistically signi ﬁcant ( p<0.5) predictor variablesComplications LogisticcoefficientOddsratiop-ValueWeight 0.380 1.462 0.004general anaesthesiatime0.028 1.029 0.036.possible link between unhealthy body weight and postoper-ative SSI.Our overall SSI numbers (11/46), even though within thepreviously reported range of SSI following humeral intra-condylar ﬁssure surgery,1–6are high when compared withother clean, elective canine orthopaedic surgical proce-dures.12Factors that have been reported to in ﬂuence SSI inclean, elective canine orthopaedic surgery include bodytemperature, intact males, general anaesthetic time, surgicalduration, perioperative antibiotic administration timing andsurgeon ’s experience.13–15,29Of these, only the patients ’body temperature was not used in our statistical analysismodel due to the inconsistent available clinical recordspertaining to methods and timings of body temperatureevaluation of the patients between 2008 and 2020. Increasedgeneral anaesthetic duration, along with patients ’bodyweight, were the only signi ﬁcant associations.There are con ﬂicting conclusions from previous studiesregarding the merit of prescribing postoperative antibioticmedications following an elective orthopaedic procedure forthe prevention of SSI.10,13 –15,29,30In this study, all patientsreceived perioperative antibiotic treatment, and 5/11 casesthat developed SSI were prescribed postoperative oral anti-biotic medications. In our study, administration of oralantibiotic medications after humeral intracondylar ﬁssuresurgery did not appear to in ﬂuence the SSI incidence.The overall complication rate of our study was high, 22/46.Minor complications (seroma) were seen in 9/22, none ofwhich had any clinical impact and all of which resolvedwithout treatment. Thirteen of 22 had major complications.Medical management of SSI using antibiotic medicationalone was successful in all but two SSI cases. SSI in onecase was refractory to protracted medical management;hence, revision surgery and staged implant upsizing from a5.5mm screw to a 6 mm were performed and no furthercomplications were reported. In the second case, persistentSSI and lameness lead to the decision of removing thetranscondylar screw (4.5 mm) 2 months postoperatively,along with prolongation of the oral antibiotic treatment.On a subsequent recheck for a scheduled revision surgery,the patient was doing well and the owner had elected not toreplace the previously removed implants.Limitations of our study include its retrospective design,the number of surgeons involved, the variability of generalanaesthesia, antibiotic protocols, postoperative care instruc-tions, implant selection, methods of follow-up, duration offollow-up, criteria used to diagnose/con ﬁrm SSI and therelatively small population sample size. We acknowledgethe risk of a type II error due to the number of cases involved,although the total number of cases exceeds all the previousstudies that have looked at both lateromedial and medio-lateral transcondylar screws and postoperative SSI with eachcategory. In addition, several SSI may have been missed in theabsence of proactive surveillance by veterinary surgeons(as many as 27.8%).31Despite the fact that our medianfollow-up time was 1 year, for 4 dogs, follow-up medicalrecords were only available for 12 weeks postoperatively.Guidelines for infection control21,22suggest that SSI surveil-lance following implant usage should be continued for 1 yearafter surgery. However, in the study by Chase and col-leagues,3which recorded the highest SSI rate (11/26) anddocumented the longest follow-up period (median: 3 years;range: 56 –436 weeks), the median interval between surgeryand SSI incidence was 10 days (range: 3 –28). In Carwardineand colleagues' study1111/82 SSIs were reported between 5and 10 days. Long-term follow-up time for the latter studywas available for 64/82 elbows. This is similar to our ﬁndingswhere the median SSI occurrence was 14 days postopera-tively (range: 7 –49). Despite the longest follow-up time being6.5 years (mean: 52 weeks, range: 12 –336) in our study, wedid not encounter any delayed onset of SSI. The fact that 30/46 cases had additional procedures performed under thesame general anaesthesia other than placement of a trans-condylar screw might have in ﬂuenced the rate of SSI andaffected direct comparison to other studies. We wouldtherefore recommend limiting the number of proceduresperformed under the same anaesthetic period, which wouldlead to a shorter general anaesthesia length, and may reducethe SSI incidence.To summarize, this study does not support the recom-mendation of placing transcondylar screw from medial tolateral to reduce SSI when treating humeral intracondylarﬁssure in dogs. However, larger population prospectivecohort studies would be required to address some of themajor limitations of our study and to consider other variablessuch as construct stiffness which might in ﬂuence SSI.

Answer 62

We reject our hypothesis on the basis that the agreementwas not poor between T 0and all subsequent time points.However, our study shows that owners may not be able toaccurately recall their dogs ’pretreatment status using theLOAD and CBPI CMI. The agreement between the actual andthe recalled pretreatment LOAD and CBPI numerical scoreswas poor to moderate with more than 60% of owners recall-ing their dog ’s pretreatment status as worse than they ratedit at the time of initial presentation. More speci ﬁcally, theagreement between the scores was moderate between T0andTable 1 Agreement of LOAD and CBPI PSS and PIS scores between T 0–T1,T0–T2,a n dT 0–T3T0–T1 T0–T2 T0–T3LOAD ICC (95% CI) 0.640 (0.483 –0.747) 0.533 (0.278 –0.696) 0.496 (0.222 –0.680)CBPI PSS ICC (95% CI) 0.450 (0.286 –0.581) 0.366 (0.107 –0.558) 0.419 (0.084 –0.641)CBPI PIS ICC (95% CI) 0.569 (0.459 –0.661) 0.559 (0.416 –0.673) 0.432 (0.219 –0.603)Abbreviations: CBPI, Canine Brief Pain Inventory; CI, con ﬁdence interval; ICC, intraclass correlation coef ﬁcient; LOAD, Liverpool Osteoarthritis inDogs; PIS, Pain Interference Score; PSS, Pain Severity Score; T 0, initial presentation; T 1, 2 months from initial presentation; T 2, 6 months from initialpresentation; T 3, 12 months from initial presentation.Table 2 Agreement of LOAD categorical scoring and CBPI QOL scores between T 0–T1,T0–T2,a n dT 0–T3T0–T1 T0–T2 T0–T3LOAD κw(95% CI) 0.449 (0.355 –0.544) 0.359 (0.239 –0.480) 0.295 (0.156 –0.434)CBPI QOL κw(95% CI) 0.319 (0.225 –0.412) 0.348 (0.239 –0.456) 0.337 (0.199 –0.474)Abbreviations: CBPI, Canine Brief Pain Inventory; CI, con ﬁdence interval; LOAD, Liverpool Osteoarthritis in Dogs; QOL, quality of life; T 0,i n i t i a lpresentation; T 1, 2 months from initial presentation; T 2, 6 months from initial presentation; T 3, 12 months from initial presentation; κw, kappaweighted..T1and T 0and T 2and poor between T 0and T 3for bothquestionnaires. Although the authors do not suggest theLOAD categorical scoring as the intended method of use ofthis CMI, for the purpose of this study, LOAD data werestrati ﬁed into categorical data to determine if this couldcompensate for any recall bias that affected absolute numer-ical values. For example, the categorical scoring wouldremain the same (moderate) for numerical scores of 12/52and 20/52 at T0and T 2, respectively, and therefore couldeliminate the difference in the numerical scores betweenthese two time points and accommodate recall bias. TheLOAD categorical scoring changed for approximately 50% ofthe cases at T1and for greater than 50% of the cases at T 2andT3. These results suggest that neither the numerical nor thecategorical LOAD scores would be reliable when used retro-spectively. Similarly, the CBPI categorical scoring onlyremained the same for just over one-third of the studypopulation at T1,T2,a n dT 3.Studies assessing the retrospective use of patient-reported outcome measures in people report similar ﬁnd-ings.23–25,27 –30Patients tended to recall their preoperativestatus as worse after lumbar spinal surgery, total kneereplacement, and total hip replacement. Similarly, patientswho had cervical spinal surgery overestimated their preop-erative disability following surgery, although they couldaccurately recall their preoperative pain and QOL.28Higherrecalled pretreatment CMI scores could lead to overestima-tion of the effectiveness of an intervention particularly whenthere are no additional objective outcome measures.While it is easy to question the validity of this retrospec-tively acquired data, it is important to consider why varia-tions in these scores may have occurred. As the data requireparticipants to complete the questionnaire retrospectively,variation between contemporaneously and retrospectivelyacquired scores could be explained by memory distortion,cognitive dissonance reduction theory, and/or responseshift.34–36Biases leading to inaccurate recollection of pre-interventional state due to memory effects include recallbias, implicit theory of change, and present state effectalthough it has been suggested that all three be consideredunder the umbrella term of recall bias.37Implicit theory ofchange assumes that responders/observers cannot recall thepreintervention status but instead reconstruct it based onthe current state and how this has probably changed in theintervening period.35Similarly, the present state effectsuggests that responders use their current perceived healthstatus to reconstruct their preinterventional status.38Forexample, an owner may assume their dog must haveimproved following an intervention and will therefore useimplicit theory to conclude that their preintervention statuswas worse and therefore induce a negative response biaswhen completing the retrospective questionnaire.Effort justi ﬁcation is derived from the cognitive disso-nance theory.34The effort justi ﬁcation theory suggests thatFig. 2 CBPI PSS score change between ( A)T0and T 1,(B)T0and T 2,a n d( C)T0and T 3. CBPI, Canine Brief Pain Inventory; PSS, Pain Severity Score;T0, initial presentation; T 1, 2 months from initial presentation; T 2, 6 months from initial presentation; T 3, 12 months from initial presentation.Fig. 3 CBPI PIS score change between ( A)T0and T 1,(B)T0and T 2,a n d( C)T0and T 3. CBPI, Canine Brief Pain Inventory; PIS, Pain InterferenceScore; T 0, initial presentation; T 1, 2 months from initial presentation; T 2, 6 months from initial presentation; T 3, 12 months from initialpresentation..when there is some form of personal sacri ﬁce (mental,physical, or monetary) to achieve a goal, dissonance isaroused; to reduce this dissonance, a more positive responseis seen toward the end goal.34For example, an owner electingto have a total hip replacement performed on their dogundergoes an emotional, physical, and in some scenariosmonetary stress resulting in dissonance arousal. To reducethis dissonance, the owner may want to perceive a betteroutcome to surgery than may have actually occurred, justi-fying this “sacriﬁce.”This again may result in a negativeresponse bias when completing the questionnaireretrospectively.The LOAD questionnaire has been used to retrospectivelyrecall the preoperative status of patients undergoing totalhip replacement greater than 1 year after surgery15,19andthe LOAD and CBPI questionnaires to recall preoperativestatus following total elbow replacement at a median of33 months postoperatively. While the authors appreciatethis is a simpli ﬁed approach to a complex process andassumes that all score variation is due to recall bias, applyingthe results of our study to the ﬁndings of Henderson andcolleagues19and De Sousa and colleagues16could illustrate apotential consequence of recalled CMI data. Applying themedian LOAD score change at T3to the data of Henderson andcolleagues19is unlikely to affect the signi ﬁcance of thatstudy. However, it is possible that contemporaneous preop-erative LOAD scores, had they been collected, would havebeen lower than those returned by the retrospective com-pletion used at follow-up in that study. Similarly, while DeSousa and colleagues16did not demonstrate a signi ﬁcantdifference between pre- and postoperative LOAD, it is feasi-ble that, based on the data in this study, preoperativemobility status may have been signi ﬁcantly better thanrecalled indicating a potential negative impact of total elbowreplacement on mobility. They reported a signi ﬁcant im-provement in PIS and PSS. If the median PIS and PSS scorechange at T3 were applied, these scores would not besigniﬁcantly improved postoperatively and would questionthe bene ﬁt of total elbow replacement in canine patients.In contrast, response shift is not a consequence of memo-ry effects but is instead de ﬁned as a change in the meaning ofa target construct as a result of change in internal standards(recalibration), a change in values or priorities (reprioritiza-tion), or a change in the de ﬁnition (reconceptualization) ofthe target construct.39Response shift is well recognized inlongitudinal QOL studies in people.35Traditionally, treat-ment effect is calculated by subtracting the pretest scorefrom the posttest score. However, this does not consider theeffect of response shift.40The “then-test ”is the most com-mon methodology used in human studies to quantify recali-bration response shift (RRS).36,40,41The then-test is similarto the methodology used in the present study as well as thatof De Sousa and colleagues16and Henderson and col-leagues.19That is, respondents are asked to complete aquestionnaire based on how they were prior to an interven-tion.40,41RRS is calculated as the then-test minus the pretestscore and the adjusted treatment or time effect is calculatedas the posttest minus the then-test.40,41The main perceivedadvantage of this approach is that it assumes the then-testand posttest share the same internal standards and aretherefore a better estimate of treatment effect.40,41Forexample, a client may initially rate a lameness as mild usingthe LOAD questionnaire. Following treatment, the client maysee an improvement in lameness but not resolution andagain rate the lameness as mild. On the retrospective then-test, the client may instead rate the initial lameness asmoderate due to a recalibration of internal standards.Using the traditional method, there would be no treatmenteffect due to the response shift, whereas the then-testmethodology would identify a positive treatment effecthaving accounted for response shift. One may thereforededuce from this that our study has simply calculated theRRS and not the effect of recall bias. Similarly, one couldconclude that De Sousa and colleagues16and Henderson andcolleagues19calculated the adjusted treatment response,taking into account the RRS, and as such may give a moreaccurate re ﬂection of the magnitude and direction of treat-ment effect.In reality, the retrospective nature of the then-test meth-odology makes it susceptible to recall bias and implicit theo-ries of change as well as social desirability responding andeffort justi ﬁcation.42RSS and recall bias should therefore beconsidered as two distinct sources of variance in then-testscores.41It is likely that the retrospective CBPI and LOAD scoresin this and other studies have been affected by recall bias andRRS. It has been suggested that determining the extent recallbias affects then-test scores is essential to determine thevalidity of this methodology in calculating RRS.41The currentinstrumentdesigns means it is not possibleto calculatetowhatextent recall bias affects LOAD and CBPI. The LOAD and CBPIquestions are composed predominantly of perception- andevaluation-based questions and are therefore susceptible torecall bias, response bias, and response shift. Further studiescould focus on trying to assess the degree that recall biasaffects retrospective LOAD and CBPI scores and determine towhat extent variation in score re ﬂects RRS. Recall bias could beconsidered a special form of error in measurement.21,22Therefore, including performance-based questions may allowcalculation of variation secondary to recall bias.41For exampleyou could ask an owner to recall how long it took their dog towalk 100 m; this value is unlikely to be affected by responsebias or response shift and therefore failure to provide thecorrect answer would be considered recall bias. Alternatively,some authors suggest completing neuropsychological testswith assessment of response shift limited to those whodemonstrate cognitive intactness,41although this may bebeyond the scope and abilities of many veterinary studies.The time between T 0and subsequent time points of CMIcompletion was the only factor shown to signi ﬁcantly affectowners ’recollection in the present study, that is, the longerthe time from initial completion of the CMI, the greater thedifference between the recalled and T 0CMI scores. Theagreement between the preoperative status and the recalledpreoperative status was good to excellent at 6 and 12 weeksfollowing total hip replacement in people.43,44In this study,the agreement between the pretreatment status and the.recalled pretreatment status of a dog was poor to moderatefor dog owners at 8 weeks from treatment; the agreementwas moderate for the LOAD and CBPI PIS scores and poor forthe CBPI PSS between T0and T 1. The ability to accuratelyrecall a dog ’s preoperative status within a time frame lessthan 2 months, as in humans, is unknown. It is possible thatother factors may have affected owners ’recollection. Inhuman medicine, there is con ﬂicting evidence regardingthe impact of age and mental health on patients ’recollectionof their preoperative status. Recalled patient-reported out-come measures following arthroscopic rotator cuff repairwere more likely to be accurate when reported by youngerpatients, and a history of mental health condition was foundto have no effect on recall accuracy in the same study.30Comparable results regarding age were demonstrated by astudy assessing patients ’preoperative recall after kneearthroplasty25; however, in this study, patients with lowmental health had poorer recall of function. Assessment ofthe effect of such owner-speci ﬁc variables on owner recol-lection was beyond the feasibility of the current study.Data in this study were collected mostly via a telephoneinterview including less than 50% of the recalled question-naire scores at T 1and all the scores at T 2and T 3time points.To the authors ’knowledge, the effect of the method ofquestionnaire completion (via telephone interview, e-mail,or by using paper-based questionnaires) on the patients ’orobservers ’recollection has not been investigated and goesbeyond the objective of this study. A recent study in peoplesuggested that patient-reported outcome measure data wereequally reliable when these were collected contemporane-ously via a telephone interview or using paper-based ques-tionnaires.45Paper-based questionnaires may be moresusceptible to primacy effects (responders select the ﬁrstagreeable option), whereas telephone interviews may bemore vulnerable to recency effects (responders select thelater options).46If the extremes of these response ordereffects were applied to the LOAD questionnaire and ourstudy design, this could go some way to explain the differ-ence in T0and recalled LOAD scores reported. However, ithas been shown that respondents were less likely to showrecency effects when the response options were given at aslow pace over the phone.47Questionnaire completion viae-mail may have eliminated this variable; however, it hasbeen demonstrated that telephone surveys have a muchhigher response rate, therefore increasing the volume ofdata that could be acquired over a given period of timeand reducing the risk of nonresponse bias.48We chose the LOAD and CBPI questionnaires to evaluateowners ’recollection in the present study as these are the CMIused at our institution, and these two CMI have been usedretrospectively in previous veterinary studies.15–19Theresults are therefore speci ﬁc to the LOAD and CBPI. Furtherinvestigation is required to assess owners ’recall accuracyusing other CMI. Despite that the LOAD and CBPI question-naires were validated using dogs that received medicalmanagement, in the present study they were used for casesthat received surgical management as previously done inother studies,15–17,19where the questionnaires were used toassess the outcome of surgery. Although one could questionthe use of LOAD and CBPI in the cases with orthopaedicdisease other than osteoarthritis, our study population wasdiagnosed with diseases that are associated with develop-ment of secondary osteoarthritis, a very common conditionwith prevalence ranging from 20 to 80%.49,50The time points for the recalled CMI scores were deter-mined based on standard clinical practice at our hospital.Most orthopaedic surgeons reassess the patients at approxi-mately 8 weeks following treatment; the medium- and long-term outcome of a treatment is determined at approximately6 months and a year following treatment in the veterinaryorthopaedic literature.51The questionnaires were completed by 80, 57, and 37% ofthe study participants at T 1,T2, and T 3, respectively. Althoughone could consider that the results of the current study mayhave been affected by selection and nonresponse bias due thelower response rate at T2and T 3with more than 50%participant “drop-out ”at T 3,52it has been shown by studiesin people that surveys with low response rates may still bevaluable and that surveys with high response rates may stillbe subject to bias.53,54Aﬁnal limitation of this study was that the study popula-tion was not standardized and affected by variable condi-tions. Future studies may wish to investigate the recallaccuracy using CMI for a speci ﬁc orthopaedic condition.In conclusion, owners ’perception of the preoperativestatus of their dog at /C212 months after treatment may notrepresent the true preintervention status of their dog. Ret-rospective use of the LOAD and CBPI is subject to variation inpreintervention scores and until there is a better under-standing to what extent this variation can be attributed tothe effects of recall bias, response shift, and implicit theory ofchange, the authors can only recommend the use of contem-poraneously collected CMI data. Retrospectively collectedCMI data may not be reliable even when collected less than6 months from the time of treatment.As such, studies that use retrospectively collected CMIdata obtained at /C212 months after treatment should beinterpreted with caution.

Answer 63

The results of the current study showed that neoplasia was the most common diagnosis (81%) in cats undergoing splenectomy, with MCT (42%) and HSA (40%) representing the most common primary neoplasia. While the frequen -cy of splenic MCT was similar to previous reports (15% to 53%), the percentage of cats with HSA was higher in this study compared to the 21% reported by Gordon et al.2,4,10,22 Nonneoplastic lesions were diagnosed in 19% of cases. The retrospective nature of this study presents challenges in assessing the indications for splenectomy in those cats. However, it may be related to the appearance of the spleen during diagnostic imaging or intraoperatively. It is impor -tant to note that cats with a documented or suspected his -tory of trauma were excluded from this study. Moreover, all 15 cats (24%) presented with spontaneous hemoabdo -men were diagnosed with splenic neoplasia and HSA was the most common diagnosis (80%), making unwitnessed trauma highly unlikely. In the only study investigating he -moabdomen in cats, Culp et al13 reported that the etiolo -gies of nontraumatic hemoabdomen in cats were evenly distributed between neoplastic (46%) and nonneoplastic diseases (54%); however, the spleen was the most common location for neoplasia (37%) and HSA was described as the most common tumor (60%).The accuracy of cytology in this study for diagnos -ing splenic neoplasia was moderate (73%). This is similar when compared to other studies including predominantly canine samples.6,7,26 As expected, diagnostic accuracy in -creased in cats with MCTs while nondiagnostic cytology results were common in cats with HSA. Few studies in dogs have attempted to evaluate the use of different di -agnostic methods to help differentiate between benign and malignant splenic lesions. However, no sensitive and specific predictors of malignancy were identified and his -topathologic evaluation remains the gold standard.5,8,27,28In this study there was a significant difference be -tween the MST for a cat with a neoplastic (136 days) versus a nonneoplastic lesion (715 days, P < .001), even if some cats with normal spleens had concurrent neoplasms in oth -er locations. Splenectomy is often considered for cats with splenic MCT, regardless of the extent of the disease and can palliate clinical signs in cats with HSA.4,22 Previous studies reported MSTs for cats undergoing splenectomy for MCT ranging from 132 to 1140 days.4,20,21,29 Similar to Kraus et al,20 who reported a MST of 390 days, the MST for this sub -group of cats undergoing splenectomy for MCTs was 348 days, with over 60% of cats dying or being euthanized for causes not associated to the MCT.For cats with splenic HSA, outcome data is scarce due to small case numbers and the population heteroge -neity. Median survival times of 77 to 197 days have been previously reported.4,13,30 Similarly, an MST of 94 days was reported in our population with all cats dying or being eu -thanized due to the disease. Based on those results, prog -nosis for cats diagnosed with a splenic HSA remains poor. This subgroup of cats was more likely to have hemoab -domen, a splenic mass and/or anemia; this presentation should prompt clinicians to favor a diagnosis of HSA.Prognostic variables in cats undergoing splenec -tomy have been inconsistently reported in the litera -ture. In this study, preoperative anemia and presence of metastasis in other organs were found to negatively affect survival.Anemia is a common finding reported in 14% to 70% of cats with MCT and over 80% of cats with visceral HSA.13,20,29,31 This could indicate a perioperative blood loss (hemoabdomen), hemolysis, microangiopathy, sys -temic inflammation, disseminated intravascular coagula -tion, or a chronic disease process.13,20Kraus et al20 reported that administration of a blood product was a negative prognostic factor in cats un -dergoing splenectomy for MCTs. The need for a blood transfusion could indicate a greater degree of anemia, but this factor was not correlated with prognosis in this cohort. Evans et al22 also described that anemic cats with splenic MCTs had numerically shorter tumor specific sur -vival times than nonanemic cats but this difference was not significant, possibly related to the population size.It has been previously stated that cats with splenic MCT benefit from splenectomy even in the presence of systemic involvement.22 However, the current literature is conflicting regarding the prognostic impact of distant organ or nodal metastasis. Presence of mastocytemia, liver and lymph node metastasis did not negatively af -fect prognosis in 2 studies,22,29 whereas Sabattini et al32 reported that cats with a MCT localized to the spleen had better outcomes than those with other organ in -volvement. By contrast Kraus et al20 reported that while additional nonsplenic organ involvement did not impact survival, lymph node metastasis negatively affected sur -vival. While in our study involvement of one or more or -gan system was found to be a negative prognostic fac -tor, the inclusion of cats with HSA and other neoplasia in our analysis could have biased the results; conclusions for specific tumor types cannot be obtained.The main limitation of the present study is its mul -ticentric retrospective nature, which could have in -creased the variability in management and treatment of this population. Investigations, staging, periopera -tive management and follow up protocols were not standardized and occasionally incomplete or inconsis -tent. Blood smears were not retrospectively reviewed to corroborate prior platelet counts, and therefore pseudothrombocytopenia could not be fully excluded. The variability of the histopathologic diagnosis could preclude a reliable statistical analysis. The histopatho -logical specimens or cytological examinations were not reviewed by a single clinical or anatomical pathologist.In conclusion, the current study provided evidence that cats undergoing splenectomy are likely to be diagnosed with splenic neoplasia. Splenic HSA was more frequently Table 5 —Multivariate Cox proportional hazards analysis results determining factors associated with survival after splenectomy in cats. Survival Cox proportional hazards analysis OR 95% CI P valueTransfusion 1.04 0.34–3.11 .944Abdominal effusion 1.27 0.42–3.76 .666Hemoabdomen 0.94 0.18–4.72 .941Histological diagnosis 2.79 1.09–7.17 .320Metastasis 5.26 1.83–15.12 .002Anemia 4.22 1.40–12.69 .010Unauthenticated | Downloaded 11/03/23 05:53 AM UTC1652 JAVMA | NOVEMBER 2023 | VOL 261 | NO. 11reported compared to previous studies and potentially con -tributed to the overall poor prognosis in this cohort. A poorer prognosis could be expected for cats presented with anemia or involvement of other organs during staging.AcknowledgmentsNone reported.DisclosuresThe authors have nothing to disclose. No AI-assisted technologies were used in the generation of this manuscript.FundingThe authors have nothing to disclose.

Answer 64

Arthroscopic evaluation of the feline hip through a supra-trochanteric lateral portal was feasible and subjectivelystraightforward in the cadaver hips in this study using atechnique similar to that previously described in dogs.10Saunders et al. also described a technique for canine hiparthroscopy using a two-portal system for joint evalua-tion.19The optimal limb position for safe creation ofarthroscope and instrument portals in canine hips asdetermined in Saunders ’study was slight limb abductionand 30/C14hip flexion with simultaneous application of distaltraction to the tibia.19In this feline study, maximum jointdistraction, atraumatic portal insertion into the joint, andoptimal joint visualization were facilitated with the limbin neutral duction, 90/C14hip extension relative to the longaxis of the pelvis, and application of traction to the distalfemur with simultaneous counter pressure on the ischiatictuberosity. This limb position was optimal for visualizingall aspects of the joint except for the cranial joint pouch,which was better visualized with the hip further extended.Portal creation and scope insertion were subjectivelyeasy to perform in the feline hip. In most cases, the scopewas able to be inserted on the first attempt and in allremaining hips the scope was able to be inserted on thesecond attempt. Like the canine hip arthroscopy studyperformed by Saunders and colleagues, arthroscope andinstrument portal orientation in this study was describedusing a clock-face analogy with the greater trochanter asthe reference point at the center of the clock. The scopecannula was inserted at the 12 o'clock position and thisportal location resulted in a safe distance between thescope cannula and the two main neurovascular structuresnear the hip, the sciatic nerve and caudal gluteal artery.In this study, the sciatic nerve was an average distance of4.3 mm (range 1 mm –10 mm) caudal or caudo-dorsal tothe scope cannula. The fluid egress/instrument portalwas located cranial to the scope portal (10 o'clock positionin left hips and 2 o'clock position in right hips) and thusthe sciatic nerve was not at risk of injury in any hip in thisFIGURE 5 Gross dissection of the left hip region alloweddirect measurement of the shortest distance between thearthroscope cannula (red arrow) and the sciatic nerve (blackarrow). The location of the instrument portal is indicated by thelight blue arrow.FIGURE 6 Gross dissection imagesof two feline femoral heads after Indiaink staining to identify cartilage injury.The majority of hips had several minor,partial thickness cartilage lesions postarthroscopy (A) but one hip displayed afocal full thickness region of cartilageinjury (indicated by the white arrow)secondary to scope cannulaimpingement on the middle region ofthe femoral head (B).1206 BOUNDS and HUDSON 1532950x, 2023, 8, study. The caudal gluteal artery was located caudal to thesciatic nerve in all hips and was not damaged during por-tal creation in any hip. Due to the caudal location ofthe sciatic nerve and caudal gluteal artery relative to thegreater trochanter, creation of portals caudal to the12 o'clock position should not be attempted. Saunderset al. previously found that, in canine hips, more caudalportal positioning resulted in direct contact of the arthro-scope cannula with the sciatic nerve in most specimens.The limb position and portal locations described in thisstudy resulted in minimal gross periarticular muscletrauma. Blunt trauma from portal creation resulted in lon-gitudinal splitting between muscular fibers, rather thanmuscle fiber transection. Our study demonstrates that not-withstanding the small size of feline patients, coxofemoralarthroscopy can be performed safely if using appropriatelimb positioning and accurate portal localization.Although arthroscopy has many benefits, the most com-mon complication associated wit ha r t h r o s c o p i cj o i n te v a l u a -tion is ICI.8In this study, ICI occurred in all hips but theseverity of lesions was considered minor in most hips. This issimilar to reported ICI postarthroscopy in other joints indogs.8,26Previous studies evaluating canine stifle articularcartilage ICI post arthrosco py reported a 93% incidencemostly consisting of partial thickness lesions.8,26ArthroscopicICI lesions can be created during portal establishment, byarthroscope cannula insertion o rm a n i p u l a t i o n ,b yt h ee g r e s sneedle, or while inserting or manipulating hand instrumentsinside the joint. In the present study, the majority of ICIlesions were located at the middle region of the femoral headin the area of arthroscope cannula insertion and manipula-tion. The long-term clinical ef fects of partial thickness ICIlesions on canine and feline joints is unknown; however, inthe experimental setting, full thickness cartilage groovelesions have been shown to induce progressive osteoarthriticchanges in dogs.28Canine articular cartilage has been shownto lack substantial regenerative capabilities,29so it is impor-tant to utilize strategies to dec rease ICI during arthroscopy.Adequate joint distraction prior to portal development andcannula insertion and during the arthroscopic procedure isone simple strategy that may help facilitate atraumaticentrance into the joint and decreased ICI. The limb positiondescribed in this study resulted in maximal joint distractionin our cadaver hips and utilization of this described limbposition may help to reduce the risk of substantial ICI duringportal creation and hip arthroscopy in cats.Articular structures of interest were identified andevaluated in all feline hips in this study. Structuresevaluated in the feline hips in our study were similar tothe intra-articular structures assessed during canine hiparthroscopy.10,18 –20Visual joint evaluation was per-formed successfully in all hips using an arthroscopeand egress needle only. Use of a blunt probe duringfeline hip arthroscopy consistently improved visual eval-uation of the DAR and dorsal joint capsule but it wasnot necessary to see/evaluate either of these structures.The two hips with radiographic evidence of degenera-tive joint disease were included in the study to evaluateif hip arthroscopy was feasible in diseased as well asnormal feline joints. Arthroscopic evaluation of arthriticcanine hips is more difficult in comparison with nonar-thritic hips due to joint capsule thickening and result-ing decreased joint distraction.10Although it has yet tobe studied, similar synovial thickening associated withfeline hip dysplasia and osteoarthritis could make felinehip arthroscopy more challenging. In our study, arthro-scopic evaluation of two feline cadaver hips affected byDJD was subjectively no more challenging than evalua-tion of normal feline cadaver hips and all intra-articularstructures of interest were identified in the 2 feline hipsaffected by DJD.Limitations of this study include the use of cadaversand small sample size. Supporting musculotendinousstructures in cadavers lack tone, which may exaggeratethe degree of joint opening achieved when comparedwith anesthetized clinical patients. Post mortem changesand freeze-thaw cycles affect articular cartilage making itmore susceptible to ICI.30The prevalence of ICI in thisstudy may not be accurate when compared to clinicalfeline patients undergoing hip arthroscopy. In this studywe evaluated the use of a 1.9 mm diameter needle scopeonly so our results cannot necessarily be extrapolated toresults that might be achieved using a larger diametertraditional arthroscope for feline hip arthroscopy.Arthroscopic examinatio no ft h ef e l i n ec o x o f e m o r a ljoint is feasible via a supratrochanteric lateral arthroscopicportal using a 1.9 mm, 0/C14arthroscope. Portal placement issimilar to that described for u se in canine hip arthroscopybut optimal limb positio nd i f f e r ss l i g h t l y .A l li n t r a - a r t i c u l a rstructures commonly evaluated in canine hips can also beidentified in feline hips. Base do nt h ef i n d i n g so ft h i ss t u d y ,arthroscopy may be consider ed as an option for minimallyinvasive evaluation of the feline hip joint.ACKNOWLEDGMENTSAuthor Contributions: Bounds CA, DVM, MS: Madesubstantial contributions to the acquisition, analysis andinterpretation of data for the study, and drafted the man-uscript. Hudson CC, DVM, MS, DACVS: Designed thestudy, performed coxofemoral arthroscopy, performedthe gross dissections, and assisted with writing and revis-ing the manuscript.CONFLICT OF INTEREST STATEMENTThe authors declare no financial or other conflicts ofinterest related to this report.BOUNDS and HUDSON 1207 1532950x, 2023, 8,

Answer 65

This study of 41 dogs with pancreatitis and EHBO reported a higher survival rate of 94% for those treated surgically (n = 19) compared to prior stud -ies focusing on surgical management of pancreatitis and EHBO.3–5,7,24,25 We also reported a lower survival rate of 57% for those treated medically, compared to 2 recent studies in which survival of those treated medically was 78%8 and 94%.26The optimal treatment for pancreatitis-associat -ed biliary obstruction in animals is controversial, as it has been in humans. Biliary obstruction second -ary to pancreatitis may be transient and surgical in -tervention not indicated in these patients. Surgical treatment may be inherently risky in a compromised patient, and there may be long-term complications associated with certain procedures, such as biliary rerouting and biliary stenting.6,19,25,26 Some of these Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 11/03/23 06:53 AM UTC1698 JAVMA | NOVEMBER 2023 | VOL 261 | NO. 11issues have been overcome in human medicine with the advent of more advanced diagnostics and less invasive endoscopic and laparoscopic interventions; however, controversy remains over the timing of such interventions and the benefit of biliary decom -pression prior to more definitive surgical therapy.15,27Of 82 dogs with pancreatitis-associated biliary obstruction, across 10 studies, treated surgically by multiple modalities including cholecystoenterosto -my, choledochal stent, cholecystostomy tube, per -cutaneous ultrasound-guided cholecystocentesis, and exploratory laparotomy with pancreatectomy, pancreatic abscess debridement, and common bile duct flushing, 53 (65%) dogs survived, with individu -al report mortality rates ranging from 13% to 75%.3,5–8,24,25,28,29 In this report, of 19 dogs undergoing sur -gery for extrahepatic biliary obstruction secondary to pancreatitis, 18 (95%) survived to discharge. All 15 dogs treated by cholecystoenterostomy survived. The 1 nonsurvivor was euthanized intraoperatively due to severe pancreatitis, biliary obstruction, and a necrotic gallbladder that precluded biliary diversion. These 18 patients were still alive at 2 months. At 1 year, 15 of 18 were still alive, with the 3 deaths being due to hepatobiliary disease.Of those treated medically, 20 of 22 (91%) sur -vived to discharge; however, only 12 of 21 (57%) were alive at 2 months, with 6 being euthanized due to EHBO, up to 7 weeks post discharge. This result is very different from that of a recent study, in which 31 of 33 (94%) of medically managed dogs with pancreatitis-associated biliary obstruction survived to discharge.8 Follow-up was more limited in this study, although 1 patient was mentioned to have returned for pancre -atitis-associated biliary obstruction twice in the next year, responding to medical management, and 5 dogs were reported to live for years post discharge. Only 4 dogs in that study were treated with biliary decom -pression, 1 by cholecystoenterostomy and 3 by percu -taneous ultrasound-guided cholecystocentesis, and 50% died.8 In another recent study26 of 45 dogs with pancreatitis and EHBO, a higher percentage of pa -tients treated surgically (87%) survived to discharge, compared to those treated medically (70%); however, of those surviving to discharge, the median survival time was not significantly different between treat -ment groups. Comparison between the medical man -agement provided in these 2 studies with the current study is difficult, with no study having standardized treatments, although treatments appear similar, con -sisting of crystalloid fluids, antimicrobials, analgesics, antiemetics, and gastroprotectants.8,26Overall survival, which was survival to discharge, in the above-mentioned studies was 76% and 79%,8,26 while survival to discharge was 93% and 73% at 2 months in this study. The proportion of dogs treated medically surviving to 2 months was 57%. Survival to discharge was not considered an appropriate indicator of survival in the current study, as several dogs were discharged only to be euthanized soon after. Two months was se -lected for the short-term follow-up because it may be several weeks before patients succumb to their condi -tion or a postoperative complication.3 The choice for treatment or decision to euthanize may be heavily im -pacted by owner finances, which would in turn impact survival data.The grading of severity of pancreatitis in humans is based on presence of organ failure and local com -plications such as peripancreatic fluid accumulations and pancreatic necrosis. The severity grade correlates with risk of mortality and indicates which patients should be transferred to an ICU or tertiary center.30,31 There is no equivalent classification scheme or scor -ing system in animals; however, a variety have been proposed.32–34 Further research is needed to validate the usefulness of such scoring systems in predicting outcome in dogs and cats with pancreatitis.Appearance of the pancreas at surgery can be deceptive, with 8 dogs in this study described as having a pancreatic mass at surgery, which was shown histologically to be inflammatory and not neoplastic. Of the pancreatic biopsies attempted in this study, 7 showed chronic pancreatitis, 1 acute pancreatitis, and the other 2 contained fat or lymph node. A study26 in which 15 dogs underwent surgery for pancreatitis and biliary duct obstruction reported 3 pancreatic biopsies, 1 of which was chronic pan -creatitis and 2 with no significant lesion. In another report3 of 7 dogs with chronic pancreatitis, all dogs had pancreatic masses identified at surgery and 6 had pancreatic biopsies, confirming pancreatitis and not neoplasia as suspected in all.Biliary stasis is a reported risk for biliary infec -tion,11 but of the 16 cultures obtained in this study, only 2 were positive. In a study24 of 34 dogs under -going biliary surgery, 4 of which had pancreatitis and EHBO, 24 dogs had bacterial cultures of bile, abdom -inal fluid, or liver, resulting in a positive culture in 33%. In another study5 of 60 dogs undergoing biliary surgery (12 with EHBO secondary to pancreatitis), 27 of 54 (50%) cultures were positive.The low positive bacterial cultures in our cases may have been due to antimicrobial treatment prior to sample collection but could also be due to sample collection technique. A recent study35 of cats with suppurative cholangiohepatitis found improved bac -terial detection with consolidation of samples for culture including samples of biliary debris, centri -fuged bile sediment, gallbladder mucosal scrapings, and crushed choleliths, as these sources would more likely harvest bacterial biofilms. Additionally, they demonstrated an uneven distribution of bacterial in -fection within the hepatobiliary system and identi -fied that cultures underestimate bacterial infection when compared to immunohistochemical techniques such as lipoteichoic acid immunohistochemistry and toll-like receptor expression immunohistochemistry to detect gram-positive bacterial cell wall and gram-negative bacterial endotoxin exposure.35The decision to pursue surgical intervention for pancreatitis associated biliary obstruction is made on a case-by-case basis and is in part based on per -ceived severity of the condition and persistence of biliary obstruction. There is limited information on minimally invasive techniques for biliary drainage in dogs, with only a few studies with small numbers Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 11/03/23 06:53 AM UTC JAVMA | NOVEMBER 2023 | VOL 261 | NO. 11 1699reporting on the outcome of treatment of pancre -atitis and biliary obstruction with either ultrasound-guided percutaneous biliary drainage6,36,37 or tube cholecystostomy.20,28,38 There are anecdotal reports of dogs with pancreatitis and biliary obstruction treated medically or with biliary rerouting or stenting, and the consensus is that many dogs with pancreatitis and biliary obstruction can be managed medically. An older study28 reported a mortality rate of 50% in dogs with pancreatitis and EHBO treated with choledochal stent placement, but a recent study26 reported 13 of 15 (87%) surgically treated dogs surviving, with 11 of those dogs having choledochal stents placed. Neither study reported long-term follow-up of stented dogs assessing for known complications of stenting such as bacterial cholangitis.13,39The results of this study show that surgery is a via -ble therapeutic option for dogs with biliary obstruction secondary to pancreatitis. The mortality rate of those treated surgically was much lower than previously re -ported, and there was no difference in the long-term survival between those treated surgically and medical -ly. The concern over long-term complications is a valid one; however, out of 18 dogs with a follow-up period ranging from 4 to 70 months, only 5 patients experi -enced postoperative complications and not all of these could be definitively attributed to the effects of the sur -gery. The major risk appears to be bacterial cholangitis postoperatively, and cognizance of this risk allows for early identification of this complication, which is man -ageable with antimicrobials.The NLR and PLR are biomarkers that aid in prognostication in inflammatory, neoplastic, and cardiovascular conditions in people.21 The role of neutrophils in immunity is well-known, and while platelets are better known for their role in hemosta -sis, they are also a critical part of the immune sys -tem with various actions including stimulation and attraction of WBCs.40 Neutrophils and platelets are increased in inflammation, and multiple studies have demonstrated the correlation between peripheral lymphopenia and the severity of acute pancreatitis in people.41 The NLR and PLR have been assessed as prognostic indicators in dogs and cats with neo -plastic and inflammatory conditions, and a recent study21 of dogs and cats with pancreatitis showed elevated NLR and PLR in animals with pancreatitis versus controls, increased NLR in cats with pancre -atitis and prolonged recovery, and a significant in -crease in the PLR in dogs and cats with pancreatitis and prolonged recovery. Unfortunately, NLR and PLR showed no difference between those treated surgi -cally and those treated medically or between survi -vors and nonsurvivors in this study.There were no prognostic indicators that were useful to predict the need for surgery or that were predictive for complications. There was no difference in maximum bilirubin, maximum ALT, common bile duct diameter, or the presence of SIRS between the medically or surgically treated groups or between sur -vivors and nonsurvivors. This is consistent with previ -ous studies8,26 that also found no correlation between these variables and severity of condition or outcome.There was also no significant difference in the length of hospitalization, number of days of medical management, or time to return to adequate function between the medical and surgical groups. When as -sessing the time to return to adequate function using the starting time point of surgery, there was still no difference between the groups. The details of most patient recoveries are limited due to the retrospec -tive nature of this study, and a prospective study with regimented follow-up and objective or specific monitoring with owner questionnaires may detect a difference in the quality and speed of recovery be -tween the treatment groups.There were major limitations in this study, in -cluding those inherent in all retrospective studies, such as reliance on information in clinical records that may be incomplete or lacking the desired infor -mation, lack of standardized treatments, predefined treatment end points, and inadequate or variable follow-up intervals. The diagnosis of pancreatitis is known to be challenging, with no test being 100% sensitive, and while the surgical patients had visual and sometimes histological confirmation of the diag -nosis, the medically treated dogs did not have this definitive diagnosis. The cause of death was based on clinician assessment in the clinical record but may be inaccurate, and no patients underwent a postmor -tem. Additionally, the reasoning behind the decision to pursue surgery wasn’t always discernible and only general assumptions regarding the reasons such as clinician preference, client decision after both sur -gical and medical management were offered, per -ceived severity of the condition, and perceived lack of response to medical therapy.Another factor limiting any conclusions drawn from this study was the heterogeneity of decompression techniques. The decision to include multiple methods of decompression was influenced by past studies5,25,28 that have found similarly poor outcomes between the modes of decompression used and the desire to de -scribe the outcome for as many dogs as possible, ac -knowledging that different surgeons will have prefer -ences for particular techniques and because the aim of this study wasn’t to prove the superiority of one de -compression technique over others. Further research is needed to determine which patients are best managed medically versus surgically, what constitutes failed medical management, and the optimum time for surgi -cal intervention, but until more advanced diagnostics are readily available, it may remain a decision that is heavily impacted by clinician opinion.Given the opportunity for bias and incorrect as -sumptions in a retrospective study such as this, it isn’t possible to derive any firm conclusions or make any recommendations regarding optimal manage -ment of EHBO due to pancreatitis. The mortality rates reported in this study provide a different per -spective on the management of pancreatitis and biliary obstruction and perpetuate the debate over how to best treat this condition. Some patients may require surgical intervention to recover; however, the method to determine which patients are best man -aged by surgery remains unclear.Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 11/03/23 06:53 AM UTC1700 JAVMA | NOVEMBER 2023 | VOL 261 | NO. 11In conclusion, the optimal management for pan -creatitis-associated biliary obstruction remains un -known. The results of this study suggest that given the potential negative impacts of biliary obstruction, both locally and systemically, until minimally invasive interventions such as endoscopic retrograde cholan -giopancreatography become available, alleviation of biliary obstruction via surgical decompression may be a reasonable therapeutic option.AcknowledgmentsThe authors declare that there were no conflicts of interest.

Answer 66

This study analyzed risk factors for the develop -ment of postoperative complications in dogs that had bi-oblique PUO performed. A lighter body weight was a significant risk factor for the development of postop -erative complications, while a younger age appeared to provide a protective effect from complications.Various complications have been reported in studies describing PUO in small cohorts of dogs, in -cluding significant hemorrhage following transverse PUO,9 ulnar fracture,15 pain requiring removal of the intramedullary pin,15 seroma formation,16 and lat -eral radial head luxation.17 We did not identify any of these complications within our study. The only single- surgeon study involving a large cohort of dogs reported a range of complications including excessive proximal segment migration, delayed os -teotomy healing, infection, superficial surgical site inflammation, seroma, and cortical fissures, with a total complication rate of 12% of the entire popula -tion, but risk factors for the development of compli -cations were not thoroughly investigated.14In our study, 39 of 93 limbs suffered complica -tions, and in 13 limbs, these were classified as major (13.9%). The most common major complication we experienced was an oligotrophic nonunion (8 limbs), which could have been attributable to excessive mo -tion at the osteotomy site or to inadequate cellular activity at the osteotomy site. The latter, in particular, could have been predisposed by iatrogenic thermal necrosis caused by the saw blade and subsequent reduced cellular activity at the level of the osteotomy site. Temperatures of 55 °C for 1 minute can result in osteonecrosis and may cause osseous resorption and delayed healing of the osteotomy site.19 Heat generation is also influenced by saw blade speed, cutting speed, blade design, concomitant irrigation and location within the bone (eg, depth within thick cortical bone, cis or trans cortex).20–24 Use of a sharp saw blade is widely advocated during performance of osteotomy procedures, with excessive blade wear from reuse in multiple procedures having the po -tential to increase temperature at the cutting inter -face.25 While thorough lavage using sterile saline was carried out while performing the osteotomy to try to limit potential for excessive temperatures at the saw-to-bone interface, data regarding whether a new os -cillating saw blade was used for each procedure or whether saw blades were reused in some individuals were not recorded. Excessive motion at the level of the osteotomy can indeed be considered one of the possible causes for the viable nonunion we experi -enced. However, oligotrophic nonunions are mainly caused by lack of cellular activity rather than simply excessive motion at the osteotomy/fracture site,26 hence the suspicion that thermal necrosis (with sub -sequent damage to the cellular environment) may be considered the primary reason for the complications we experienced.Increasing body weight was associated with a reduced risk for postoperative complications in our study. We suspect that this was most likely to be attributable to the difference in limb morphology be -tween lighter and heavier dogs. The majority of our lighter-weight dogs were chondrodystrophic dogs. While we were unable to statistically confirm a direct association between being chondrodystrophic and the development of complications, we cautiously postulate that the relatively marked curvature of the ulna in small chondrodystrophic dogs might increase the risk for angular deviation at the osteotomy site because any mechanical forces applied along the bone (such as axial weight-bearing forces or pull of the triceps muscle on the olecranon) would be more eccentric to the long axis of the ulna at the level of the osteotomy than in a nonchondrodystrophic dog. Another possible explanation for the increased risk for complications in lighter dogs would be that the vascular supply to the bone may be reduced in small -er-breed dogs and therefore less conducive to bone healing. This has not been documented in the ulna specifically but has been demonstrated in the distal radius of small-breed dogs.27 Given that complica -tions occurred in 10 of 18 chondrodystrophic limbs, we suggest caution when considering an ulnar oste -otomy procedure in this group of dogs. Further study is warranted to explore whether low body weight or a chondrodystrophoid conformation might be more strongly associated with complications or what mea -sures might be applicable to limit any possible risk in these groups of dogs.The association between increasing age and the risk of complications can be explained by the supe -rior biological activity of bone in skeletally immature dogs by comparison with older dogs. Our finding that 15 of 17 dogs older than 24 months experienced complications raises particular concerns for this age group in which the cellular activity of diaphyseal bone with limited soft tissue attachments and lim -ited medullary space may contribute negatively to the excessive motion between ulnar segments. We therefore recommend caution when considering proximal ulnar osteotomy in older dogs; use of strat -egies to improve the mechanical and/or biological environment is recommended.Our study found that there is no optimal loca -tion for performing an ulnar osteotomy. The aver -age location of the osteotomy was 33% of the ulnar length, but in cases that developed complications, the osteotomy was performed at 32% of the ulnar length. Although the incidence and nature of com -plications were somewhat different from those in the study by Caron et al,14 that study reported that the average osteotomy position in limbs that developed complications was similar to our study (36% of the ulnar length). They also found that there was no dif -ference in osteotomy location between limbs that experienced complications and those that did not.14 An oblique osteotomy trajectory has been suggest -ed to be effective at the time of restraining proximal ulnar segmental motion in the sagittal and trans -verse planes and reduce the risk of postoperative complications arising from excessive proximocaudal displacement.14 Our results revealed that the oste -otomy angle did not influence the complication rate. Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 11/03/23 06:54 AM UTC6 A study of a larger cohort of dogs involving different osteotomy angles is warranted to identify whether an optimal osteotomy angle (to minimize complica -tions and improve clinical outcomes) exists.The position of the osteotomy in relation to the interosseous ligament can influence the potential displacement of the osteotomized proximal ulnar segment.14 If the osteotomy is positioned too distal and the ligament is not disrupted, this could limit the motion of the proximal ulnar segment. Conversely, if the osteotomy is too proximal or the interosse -ous ligament is released, this could lead to excessive motion or instability of the proximal osteotomy seg -ment. In 50 of 93 limbs in our study, the interosse -ous ligament was deliberately disrupted to allow the proximal ulnar segment to move more freely; how -ever, univariate analysis failed to identify any signifi -cant association between this additional procedure and the development of complications. Further stud -ies of a larger cohort of dogs are required to estab -lish both safety and clinical efficacy of interosseous ligament release in association with PUO.Several limitations of our study need to be ac -knowledged. These include its retrospective nature, the possibility of having incomplete and/or inconsis -tent clinical records, the relatively small and hetero -geneous population of dogs involved, and the inclu -sion of different elbow diseases treated by bi-oblique PUO, all of which might have applied a selection bias to our analysis.In conclusion, our study suggests that while lower body weight seems to predispose dogs to the devel -opment of complications following bi-oblique PUO, a younger age seems to have a protective effect against them. Patient selection is therefore paramount to re -duce the risk of postoperative complications at the time of planning bi-oblique PUOs in dogs.AcknowledgmentsNone reported.DisclosuresThe authors have nothing to disclose. No AI-assisted technologies were used in the generation of this manuscript.FundingThe authors have nothing to disclose.

Answer 67

The results from this study support the utility of PSGs forimproving the accuracy of sagittal alignment of the femo-ral cuts and frontal plane alignment of the tibial cut incanine TKR. PSGs did not improve femoral alignment inthe frontal plane when compared to generic cuttingblocks, but this was in normal rather than pathologicalFIGURE 8 Tibial component alignment in canine total knee replacement (TKR) performed with generic or patient-specific guides(PSGs). (A) The use of PSGs was associated with a statistically significant reduction in alignment error in the frontal plane (varus-valgusalignment). (B) Sagittal plane alignment was similar in the two groups. The red line represents 3-degree threshold for axial malalignment.5Numbers above bars represent p-values (ns, not significantly different).FRACKA ET AL . 681 1532950x, 2023, 5, joints. PSGs were as effective as generic guides at preserv-ing the cranial-caudal width and the 10-degree lockingangle at the distal femur, both of which are likely to beimportant determinants of early mechanical stability in apress-fit femoral component. Our findings are consistentwith those from similar studies in human TKR, whichalso demonstrated improved alignment with the use ofPSGs.3,5,18,19In human TKR, frontal plane alignment of the tibialcomponent is a key determinant of long-term implantsurvival.4It has been suggested that restoring themechanical axis to within 3 degrees of neutral in thefrontal plane is associated with a better long-termoutcome,17,20and this has driven interest in the use ofassistive technologies such as surgical navigation21,22andPSGs to optimize tibial component alignment. We havepreviously reported that surgical navigation improves tib-ial component alignment in canine TKR,23but without acommercial veterinary navigation system on the market,these benefits cannot be realized at present. However,most veterinary referral centers have easy access to CTscanning, and the clinical success of PSGs in other areasof veterinary orthopedics, including spine surgery andlong bone deformity correction,6–14provides a strongrationale for exploring their utility in canine TKR. In thisstudy, all the knees operated with the assistance of PSGsfell within 3 degrees of neutral in the frontal plane.There is a learning curve for any surgical procedure,and total joint replacement is no exception. In the humanfield, it has been estimated that the learning curve forTHR is 50 cases, while for TKR surgeons need around80 cases for technical proficiency.24Careful preparationand attention to detail is crucial to avoid complicationsand errors that may lead to ligament damage or instabil-ity, loosening of the implant and pain.4,14,15In our experi-ence, the tibial and femoral ostectomies are the mostFIGURE 9 Femoralcomponent alignment in caninetotal knee replacement (TKR)performed with generic orpatient-specific guides (PSGs).(A) In the frontal plane, varus-valgus alignment of the femoralcomponent was similar in thetwo groups. In the sagittal plane,statistically significantimprovements in femoralcomponent alignment were seenfor the distal cut (B) and thecranial cut (C). The closingangle, important for ensuring alocking fit for the femoralcomponent, was similar in thetwo groups (D). The numbersabove bars represent p-values(ns, not significantly different).682 FRACKA ET AL . 1532950x, 2023, 5, technically challenging aspects of TKR surgery, and inac-curate cutting of the articular surfaces may contribute toerrors in tibial and femoral component position-ing.3,5,17,25,26By virtue of their use of the patient's ownanatomy as the reference, PSGs are likely to be muchbetter guides for aligning the tibial and femoral osteo-tomies. From a practical point of view, our data indicatethat PSGs use in TKR is effective, feasible and may beparticularly helpful for surgeons with limited prior expe-rience with TKR surgery. Tibial and femoral PSGs areeasy and quick to apply, require less manipulation duringsurgery than conventional cutting blocks, and allow bet-ter visualization of the anatomy following placement. Pinloosening, which is recognized as a problem whengeneric guides are used, was not see in any of the PSGcases from this study; this likely reflects the fact that thesame two pins are required to resist the forces experi-enced during all four of the femoral cuts. Additionally, asmore and more bone is resected from the femur, the bonesupport available to the guide decreases, with a concomi-tant increase in load transfer through the pins them-selves. The fact that each of the PSGs is used for a singlecut, with full bone support, may well make these pinsless prone to loosening. Additional clinical experiencewill be needed to confirm the significance of thisobservation.For surgeons doing only a few TKR cases in a year,the use of PSGs offers a very cost-effective alternative toinvesting capital in the purchase of a complete set ofgeneric TKR instruments. Moreover, many of the dogsthat present for TKR have end-stage disease and varyingdegrees of bone deformity and joint collapse that cancomplicate the use of generic cutting guides.27PSGs offera very attractive solution for these cases; however, pro-spective clinical studies are now needed to better definethe value of PSGs, and to determine the impact of betteralignment on clinical function and implant survival incanine TKR. Additionally, further studies may giveinsights into potential design improvements of the PSGswhich could further enhance their efficacy. Although theaccuracy of guides with very similar trochlear contactfootprints and guide plane dimensions has been previ-ously demonstrated for distal femoral osteotomy,13designmodifications such as the use of combined guides for >1osteotomy, or slotted guides, may prove beneficial. Slot-ted guides are used commonly in human TKR PSGs butmay have drawbacks in smaller veterinary patients, mostnotably the reduced visibility of the saw blade in thevicinity of the collateral ligaments and constrained angleof attack of the blade. Additionally, for optimal accuracy,the thickness of the blade that will be used must beplanned for in every case. The ability to easily trial guidedesign variations, and indeed to create different designsbased on case requirements or even surgeon preference,is facilitated by the custom nature of the PSGs.The use of PSGs is not without drawbacks. Placementof the PSG does require additional dissection on the cra-nial and medial surfaces of the femur (proximal to thetrochlea, to seat the initial femoral guide) and a slightlymore extensive dissection over the distal part of the tibialcrest to allow the tibial guide to seat properly under thecrest. CT scans are needed for surgical planning andguide design; these scans, and the costs associated withmanufacture of the PSGs, must then be factored into theoverall cost of the procedure. Additionally, CT scans donot provide any information about soft tissue laxity orbalancing, both of which are key determinants of successin TKR surgery. Surgeons undertaking TKR must still betrained in the fundamental principles of flexion/extension gap balancing and management of periarticularsoft tissues. It may be advantageous to consider designingmore than one tibial PSG, in the event that the initial cutis not deep enough to allow for equal tension in flexionand extension. More work, much of it feasible incadavers, will be needed to define the best approach tooptimizing joint laxity in clinical cases.In general, data for tibial cut alignment fell within aclinically acceptable range of 3 degrees of error(Figure8A,B ), but more extreme values were noted fortwo of the 16 specimens (12%). In human studies, outliers(>3/C14) have been reported in 11.1% of patients undergoingconventional TKR, but in only 4% in patients undergoingnavigated TKR.28In the present study, possible reasonsfor the presence of outliers include errors in preoperativeplanning or, more likely suboptimal application of thePSG to the bone surface, leading to inaccurate cut posi-tioning and/or trajectory.29As experience with PSGsincreases, it should be possible to define the most appro-priate locations for positioning PSGs directly against thebone surface. In a clinical setting, it will also be veryimportant to ensure that the positioning of PSGs in nothindered by the presence of thickened periarticular softtissues (e.g., medial buttress) or marginal osteophytes.The custom instrumentation used in this study wasdesigned specifically for these cadaveric specimens. STLmodels of the definitive commercial femoral and tibialcomponents were used in the planning steps to ensureaccurate alignment of the femoral and tibial cuts. Theuse of STLs of CAD files is recommended as inaccuraciesin implant sizing could result in clinically significanterrors in the positioning and alignment of the bone cuts,leading to suboptimal component alignment and/orstability.As with any cadaveric project, there were a numberof limitations in this study. These included the relativelysmall number of specimens operated within each group,FRACKA ET AL . 683 1532950x, 2023, 5, the use of healthy stifle joints as opposed to joints withosteoarthritis or deformity, and the use of specimens forwhich complete recording of bodyweight was not alwaysavailable. The preoperative measurements of planned cutalignment were made using CT in one group and plainradiographs in the other group, which may introduce thepossibility for variation in our data. Despite these limita-tions, the results of the study are clear and compelling.Additional work is now needed to determine whether theadvantages identified in this cadaveric study can be trans-lated into improved alignment in clinical TKR cases. Inaddition, a prospective clinical trial will be required tosee whether improvements in component alignment leadto measurable and clinically impactful improvements inoverall implant function and/or survival.5|CONCLUSIONS3D-printed patient specific guides improve the accuracyof tibial cut alignment and should be considered a viableoption for surgeons undertaking canine TKR.AUTHOR CONTRIBUTIONSFracka AB, MSc, DVM: Performed surgical procedures,obtained radiographic images and reviewed data. Drafted,revised, and approved the submitted manuscript. Oxley B,VetMB, DSAS(Orth): Assisted with the design and fabrica-tion of the 3D guides, provided images of the PSGs (Figure4)and helped with development of the surgical workflow.Reviewed drafts and approved the final manuscript for sub-mission. Allen MJ, VetMB, PhD: designed the study,assisted with all surgeries, and performed radiographic mea-surements and data analysis. Reviewed and revised drafts ofthe manuscript and approved the final version forsubmission.ACKNOWLEDGMENTSThe authors thank Dr Paddy Mannion (Cambridge Radi-ology Referrals) and the diagnostic imaging team at theQueen's Veterinary School Hospital for invaluable assis-tance with the CTs and X-rays for this study. STL files ofthe canine TKR implants were kindly supplied byBioMedtrix LLC.CONFLICT OF INTEREST STATEMENTThe authors declare no conflicts of interest related to thisreport.

Answer 68

This study aimed to evaluate several factors to identify potential prognostic indicators of short-term survival in dogs with GBM postcholecystectomy. Re -sults found that increasing age was significantly associ -ated with nonsurvival, both postoperatively in hospital and within 2 weeks of hospital discharge. Additionally, nadir intraoperative systolic blood pressure ≤ 65 mm Hg carried an increased probability of nonsurvival in hospital. Preoperative APPLEFAST scores and serum concentrations of CRP, haptoglobin, and 25(OH)D Table 3 —Descriptive statistics and univariable exact logistic regression results examining the association between variables and nonsurvival 2 weeks postdischarge in 25 dogs with gallbladder mucocele following cholecystectomy. No. of dogs that died No. of dogs that survived (n) n or were euthanized (n) or median (IQR) or median (IQR) OR (95% CI) P valueOutcome 25 8 17 Clinical on presentation 25 6 16 4.9 (022–333.8) .46Gallbladder perforation present 25 2 2 2.4 (0.1–40.6) .76Age (y) 25 14 (11–14) 11 (10–12) 1.7 (1.0–3.2) .04Nadir intraoperative systolic 23 73 (60–83) 70 (45–90) 1.0 (0.9–1.0) .43 blood pressure (mm Hg)Intraoperative hypotension 23 3 1 0.6 (0.0–9.1) .98 (systolic < 90 mm Hg)xULN tbili 17 2 (1–26) 1 (1–6) 1.0 (1.0–1.1) .56xULN ALP 24 21 (15–46) 17 (4–35) 1.0 (1.0–1.1) .87xULN WBC 25 0.9 (0.6–1.7) 0.9 (0.6–1.4) 1.0 (1.0–1.0) .60APPLEFAST score 19 22 (20–23) 21 (18–22) 1.1 (0.8–1.7) .58CRP (mg/L) 25 28 (10–63) 38 (11–62) 1.0 (1.0–1.0) .93Haptoglobin (mg/dL) 25 560 (376–668) 598 (425–653) 1.0 (1.0–1.0) .7325(OH)D (ng/mL) 25 32 (14–84) 60 (44–65) 1.0 (1.0–1.0) .39See Table 2 for key.Table 2 —Descriptive statistics and univariable exact logistic regression results examining the association between variables and nonsurvival at discharge in 25 dogs with gallbladder mucocele following cholecystectomy. No. of dogs that died No. of dogs that survived (n) n or were euthanized or median (IQR) or median (IQR) OR (95% CI) P valueOutcome 25 6 19 Clinical on presentation 25 5 17 0.6 (0.0–41.6) 1.0Gallbladder perforation present 25 2 2 3.7 (0.2–71.3) .47Age (y) 25 14 (14–14) 11 (10–12) 2.2 (1.2–5.0) .01Nadir intraoperative systolic 23 57 (45–70) 73 (60–85) 1.0 (0.9–1.0) .17 blood pressure (mm Hg)Intraoperative hypotension 23 4 14 1.1 (0.1–70.2) 1.00 (< 90 mm Hg)xULN tbili 17 1 (1–26) 1 (1–11) 1.0 (0.9–1.1) .57xULN ALP 24 26 (14–57) 19 (4–30) 1.0 (1.0–1.0) .57xULN WBC 25 1.2 (0.8–1.8) 0.8 (0.6–1.4) 1.0 (1.0–1.0) .46APPLEFAST score 19 22 (19–24) 21 (18–23) 1.1 (0.7–1.7) .75CRP (mg/L) 25 42 (14–64) 34 (6–62) 1.0 (1.0–1.0) .68Haptoglobin (mg/dL) 25 560 (285–675) 598 (425–654) 1.0 (1.0–1.0) .5325(OH)D (ng/mL) 25 49 (16–101) 54 (36–65) 1.0 (1.0–1.0) .86CRP = C-reactive protein. tbili = Total bilirubin. xULN = Factor times upper limit of normal of reference interval. 25(OH)D = 25 hydroxy vitamin D. P values < .05 are bolded. Nonsurvival before discharge Nonsurvival within 2 weeks postdischargeAge Probability of Probability of (y) nonsurvival (%) P value 95% CI nonsurvival (%) P value 95% CI8 1% .57 0%–4% 5% .41 0%–17%9 2% .48 0%–9% 9% .28 0%–24%10 5% .34 0%–15% 14% .13 0%–32%11 11% .16 0%–26% 23% .02 3%–42%12 22% .03 2%–42% 34% < .001 13%–55%13 39% .01 12%–67% 48% < .001 21%–75%14 60% < .001 22%–97% 62% < .001 27%–96%15 77% < .001 40%–100% 74% < .001 37%–100%16 89% < .001 61%–100% 83% < .001 49%–100%P values ( P < .05 are bolded) and 95% CIs are provided.Table 1 —Predicted probability of nonsurvival in hospital and within 2 weeks postdischarge based on age of dogs with gallbladder mucocele undergoing cholecystectomy.Table 4 —Predicted probability of nonsurvival in hospital based on nadir intraoperative systolic blood pressure in dogs with gallbladder mucoceles undergoing cholecystectomy.Nadir intraoperative Probability systolic blood of nonsurvivalpressure (mm Hg) (%) P value 95% CI45 47% .04 3%–91%55 35% .02 6%–64%65 24% .01 5%–44%75 16% .07 0%–34%85 11% .23 0%–28%95 7% .39 0%–22%105 4% .52 0%–17%P values < .05 are bolded and 95% CIs are provided.Unauthenticated | Downloaded 12/04/23 07:15 AM UTC 7were not associated with survival. However, CRP and haptoglobin concentrations were significantly higher compared to control dogs, suggesting these concen -trations could be used as biomarkers of disease.Similar to other published studies,4,18,20 the pres -ent study found a significant association between age and short-term survival. Odds of nonsurvival increased 2-fold with every additional year of age, implying that older dogs with GBM have a higher risk for worse prognoses postcholecystectomy. A potential explanation for this recurring finding could be age-associated declines in health, physical func -tion, or accumulated comorbidities43 that result in greater surgical complications and nonsurvival. Al -ternatively, pet owners might be more prone to elect euthanasia in such cases and thus older age should not necessarily be used as a stand-alone negative prognostic indicator. In contrast to other studies, the present study did not identify gallbladder perfora -tion,5,18 nadir intraoperative systolic blood pressure, or laboratory variables such as serum ALP19 or biliru -bin18 as poor prognostic indicators. However, these predictors have not consistently been identified as risk factors in other studies.1,3,4,7,19,21 Additionally, in -vestigation of the margins of the systolic blood pres -sure data did find a higher probability of nonsurvival in hospital for dogs with a nadir intraoperative sys -tolic blood pressure ≤ 65 mm Hg. Thus, severe intra -operative hypotension might be a poor prognostic indicator, which corroborates the findings of a pre -vious study4 evaluating survival in a cohort of dogs with GBM undergoing cholecystectomy in Asia.Acute patient physiologic and laboratory evalu -ation scores did not correlate with survival in this study, contrary to other studies performed in dogs with critical illness.39,44 This could be because the 5 variables used to calculate the APPLEFAST score do not account for surgical and anesthetic factors that could impact prognosis for GBM dogs undergoing cholecystectomy. Examples of such factors include whether the surgery was elective or emergent, whether the surgical approach was laparoscopic or open, and whether intraoperative hemorrhage or hypotension occurred. Furthermore, the median APPLEFAST score of the dogs with GBM in this study was 21 and no dog had a score higher than 25, which is the numerical cutoff that provides the highest specificity to predict nonsurvival.39 Thus, this cohort of dogs might have lacked the number of critically ill dogs needed to appropriately assess APPLEFAST scores as a negative prognostic indicator. Small sam -ple sizes could have compromised finding statistical -ly significant associations between survival and se -rum CRP, haptoglobin, and 25(OH)D concentrations or any of the other variables examined. Neverthe -less, a previous study37 showed that serum 25(OH)D concentrations are lower in dogs with GBM and the present study found significantly higher serum CRP and haptoglobin concentrations in dogs with GBM compared to controls, suggesting that these markers of systemic inflammation could be useful biomarkers of GBM disease. In human patients, increased CRP or reduced 25(OH)D correlates with more advanced cholecystitis,31 gallbladder perforation,44 gallbladder stasis,45 and a more complicated, painful cholecys -tectomy surgery.31,32,46 Thus, these markers might be applicable to dogs with GBM in predicting gallblad -der rupture30 or serially monitoring disease progres -sion or surgical recovery in individual patients.24,47The statistical differences in serum CRP and hapto -globin concentrations between the 2 groups could be explained by age because the healthy control group in the present study was significantly younger than the GBM group. However, there are no data in dogs to sug -gest that concentrations of haptoglobin or CRP change with age.23,48,49 Although there was a statistically signif -icant difference in CRP and haptoglobin concentrations between GBM and healthy controls, there was overlap between the 2 groups. One healthy control dog had a markedly increased CRP concentration. This dog was diagnosed with coccidiomycosis 4 months after CRP measurement and therefore could have been subclini -cally infected at the time of enrollment. Nine healthy control dogs had haptoglobin concentrations above the reference interval, possibly because haptoglobin lacks specificity for GBM disease in dogs or because the upper limit of the reference interval is not the op -timal cutoff to differentiate GBM from healthy control dogs. In 7 GBM dogs, concentrations of haptoglobin or CRP were within the normal reference interval. A pos -sible explanation for this finding is that 5 of the 7 dogs had subclinical (n = 3) to very minimal clinical signs (2), and systemic inflammation was insufficient in these dogs to raise haptoglobin or CRP concentrations above the reference interval. These findings do highlight po -tential limitations in the sensitivity and specificity of these inflammatory markers, as has been previously observed.27 Factors such as exogenous corticosteroid administration or endocrine diseases such as hyper -adrenocorticism or diabetes mellitus might also have increased haptoglobin concentrations.50Additional limitations to consider in interpreta -tion of this study’s findings are that although this was a prospective study, data such as bilirubin mea -surement and the information needed to calculate APPLEFAST scores were not available for every dog. Additionally, the surgical and treatment approach was not standardized across dogs, which could have impacted patient outcome. Furthermore, dogs from 4 different institutions were included in the study, which could have introduced some variability.Despite these limitations, this study found age and severe intraoperative hypotension to be pertinent prognostic indicators of survival postcholecystecto -my in dogs with GBM, which is valuable information considering the expenses, potential risks, and survival statistics of cholecystectomy surgery. Additionally, this was the first study to demonstrate that CRP and haptoglobin concentrations are significantly higher in dogs with GBM compared to healthy control dogs. Thus, although no significant associations were found between these inflammatory markers and short-term survival in this study, it is possible that larger sample sizes and serial measurements will elucidate the util -ity of these markers to help ascertain prognosis and monitor dogs with GBM.Unauthenticated | Downloaded 12/04/23 07:15 AM UTC8 AcknowledgmentsNone reported.DisclosuresVDI Laboratory LLC (Randy Ringold) offers testing for C-reactive protein and haptoglobin in companion animals.No AI-assisted technologies were used in the generation of this manuscript.FundingThe authors have nothing to disclose.

Answer 69

Selection of an appropriate surgical approach to the vagina for management of vaginal masses in feline patients has been infrequently discussed in the veteri -nary literature. The most commonly utilized surgical approaches in the canine patient include a combined abdominal and vestibular approach,7 a caudal celiot -omy or episiotomy alone, perineal, perivaginal, or a combination of the above.10 Less-utilized techniques include a pubic symphysiotomy9 and a bilateral pubic and ischial osteotomy.11 Only a single report4 has dis -cussed the use of bilateral pubic and ischial osteoto -my in the cat, and the short case series presented here further highlights its successful use in feline patients and promising surgical outcomes.In these 3 reported feline cases, the technique of bilateral pubic and ischial osteotomy was selected to address the large tumor size in relation to the pelvis (cases 1 and 3) or improve access to resect a multi -lobular elongated mass (case 2). Selection of a bi -lateral pelvic osteotomy allowed adequate exposure for meticulous dissection, which was not expected to be sufficient via a standard episiotomy approach for circumferential dissection of such large masses through the vagina in these feline patients. An as -sumption that a bilateral osteotomy creates sig -nificant trauma and hence increased postoperative complications such as bruising, pelvic limb ataxia, and splaying of the limbs due to obturator nerve damage is certainly a possibility with such invasive surgery. However, the 3 cases presented in this study showed only mild splaying of the pelvic limbs post -surgery, hospitalization of only 3 to 4 days, and no splaying of pelvic limbs at 14 days postsurgery. Two of the 3 cases presented with mild stranguria post -operatively. While it is possible that the bilateral pel -vic osteotomy may have resulted in inflammation of the intrapelvic musculature causing stranguria (due to inflammation/compression of the urethra in con -tact with these tissues), it is likely that this stranguria was simply related to the nature of the surgery and resection of the vaginal mass rather than the select -ed surgical approach per se. Only 1 minor intraop -erative complication of a fractured drill hole (case 2) was reported in these 3 cases, further highlighting the success of this approach for resection of vaginal masses in cats.The reported surgical technique here differed from that of the single previously reported osteoto -my technique in several ways. In the description by Saitoh et al,4 a smaller K wire (0.9 mm) was used to drill the pubic and ischial holes and the ischial/pubic bony “shelf” was reflected rather than removed com -pletely. Orthopedic wire was also used to reoppose the bone fragments, and an 8-week follow-up was reported for this patient. In our study, a larger 1.1-mm drill bit was used and the bony “shelf” removed completely to maximize access to the tumor. Due to fracture of a single drill hole, all osteotomy sites were realigned with polydioxanone suture rather than or -thopedic wire and a minimum of a 12-week follow-up was reported for these 3 cases. While it is true that reflection of the bony shelf and use of orthopedic wire may well result in better bone healing, we did not identify any clinical examination abnormalities at 12 weeks postsurgery to suggest any complications with bone healing. We acknowledge that this can only be confirmed radiographically, but performing pelvic radiographs could not be justified in patients with no clinical signs. Equally, it has been suggested that patients having unremarkable recoveries from other osteotomy surgeries, such as tibial plateau lev -eling osteotomy and medial patella luxation, are un -likely to benefit from follow-up radiography should they present clinically sound at postoperative clinical evaluations.13,14 In recognition of these findings, we feel justified in not performing postoperative radiog -raphy in these clinically sound cats.Vaginal neoplasia in cats is sparsely reported in the veterinary literature.1,2 While T-cell–rich B-cell lymphoma15,16 and mycetomas17–23 have both been reported in cats, they have never been identified with -in the vagina, making this an unusual presentation for these types of lesions. Vaginal polyps are frequently reported canine vaginal masses,5–8,23–25 yet they re -main infrequently reported in feline patients and their description is limited to a single case report.4 The case series reported here describes only the second docu -mented case of a feline vaginal polyp.The lack of literature surrounding feline vaginal tumors is likely a reflection of the neuter status in Unauthenticated | Downloaded 12/04/23 07:14 AM UTC6 feline patients. In canine patients, leiomyomas are often reported in older entire patients, with vaginal leiomyomas and leiomyosarcomas contributing 13 of 20 (65%) cases.5–8,23–25 Older, intact queens are less commonly represented in the animal population.Vaginectomy is not a commonly performed surgery, and selection of an appropriate surgical approach can be challenging when presented with sagittal and transverse CT/MRI/ultrasonographic images. Excessively large vaginal masses, such as those occupying > 100% of the width, length, and height of the pelvis, may not be amenable to a bi -lateral caudal abdominal and vestibular approach,7 and this case series highlights the use of the bilateral pubic and ischial osteotomy in these cases of exces -sively large vaginal masses in feline patients.All 3 feline patients developed mild and tem -porary splaying of the pelvic limbs, associated with abductor muscle resection/resuture rather than obturator nerve damage. This resolved shortly af -ter surgery, and ongoing complications associated with this were not reported in any case. No urinary or fecal incontinence was reported with the bilateral pubic/ischial osteotomy approach in any of these cases. It is possible that a bilateral pelvic osteotomy technique, as reported in feline patients in this study, allows for a more meticulous dissection and reduc -tion in urinary and fecal incontinence associated with inflammation/iatrogenic nerve damage.The limitations of this study included those in -herent to a retrospective case series. Errors in data collection, accurate initial data documentation, and retrieval will always remain a challenge. The 3- and 15-month follow-up telephone conversations were dependent on the owner’s opinion, and this was clearly subject to a possible error in the evaluation of the postoperative complications. In addition, rec -ognition is made to the short 3-month postoperative follow-up in 2 of the 3 cases in this case series. While this follow-up is longer than that reported by Saitoh et al,4 a longer time period would be beneficial to al -low for complications associated with bony healing. It is true, however, that no gait abnormalities or com -plications were reported at 12 weeks postsurgery in all 3 cases and at 15 months postsurgery in case 3. Vaginectomies in cats are not frequently performed; case numbers are limited despite a multicentric study aimed to negate this. Surgeon experience is likely to have a reflection on the clinical outcome.The authors recognize, with complete transpar -ency, that T-cell–rich B-cell lymphoma is a medically managed (and not a surgically managed) disease. However, in light of the initial cytological presenta -tion, with no evidence of metastatic disease, surgery was deemed appropriate with the information pre -sented. Within the aims and scope of this case se -ries, inclusion of the case into a description of surgi -cal technique and outcome appears relevant, yet the authors accept a limitation that the final diagnosis of case 1 could well affect the postoperative outcome of the surgical procedure. Indeed, case 1 showed splaying of the pelvic limbs and hematuria for a lon -ger period than either case 2 or 3. While the case series here represents a heterogenous tumor neofor -mation type, the report aims to address a standard -ized technique for surgical management of extensive vaginal tumors in cats.Bilateral pubic and ischial osteotomy for resec -tion of vaginal tumors in cats is a successful surgical approach, offering good exposure for resection of large vaginal tumors, with minimal short-term post -operative complications. In these 3 cases, no urinary or fecal incontinence was noted. Considering the positive outcome seen with vaginectomies in cats in this case series, the use of bilateral pubic and ischial osteotomies in canine patients for vaginectomies in which tumors occupy a significant percentage of the height/width/length dimension of the pelvis may well be appropriate.AcknowledgmentsNone reported.DisclosuresThe authors have nothing to disclose. No AI-assisted technologies were used in the generation of this manuscript.FundingThe authors have nothing to disclose.

Answer 70

The differences within groups in the compari -son of variables with versus those without TC were Unauthenticated | Downloaded 10/08/23 06:31 AM UTC1500 JAVMA | OCTOBER 2023 | VOL 261 | NO. 10diagnostic impact on performing TC regarding the angles of tibial translation. Measuring the ATTa and the ATTb is more complex, and thus, diagnosis via patellar ligament insertion angle and DPOI measure -ments is simpler and more objective.There is no description regarding the expected DPOI measures in relation to body weight or breed in dogs, and there is no information regarding a math -ematical ratio to render this variable more reliable and eliminate the bias of dog size in the diagnosis of tibial translation in dogs with CCL rupture. In 1 study,13 the authors quantified cranial tibial translation in millime -ters in dogs with CCL rupture, comparing measures ob -tained in a conventional manner with those obtained using the common tangent method; however, the above authors did not relate these results to healthy dogs. The DPOI measure is more often found in studies aimed at assessing the efficiency of surgical treatment by comparing radiographic images of the same patient throughout the course of the postoperative period.14The DPOI ratio, obtained from conventional ra -diographs and those taken under TC, proved to be sufficient to add a very high degree of accuracy to the diagnosis of CCL rupture. Even though dogs with a predetermined body weight range were assessed in the present study, the results might be extrapolated to dogs of all sizes. However, for more precise analy -ses, patient values for different weight ranges and, even more specifically, for different breeds should be experimentally determined. In this case, DPOI ratio can be extrapolated with higher efficiency because it eliminates the bias of animal size and the comparative value of this ratio does not change due to size. Thus, a DPOI ratio value of 1.18 can be considered a standard index for the diagnosis of CCL rupture, according to the results obtained in the present study.One limitation of this study is that radiography was performed under no sedation or anesthesia of the patient, which might have hindered adequate positioning of some more agitated or aggressive dogs. In the present study, only dogs with a surgical -ly confirmed complete CCL rupture were included, and those with a partial rupture, possibly exhibiting only a torn craniomedial or caudolateral band, were excluded. Further studies are needed to compare such measurements in patients with complete and partial CCL rupture, aiming to identify a cutoff point to separate these groups.AcknowledgmentsThe authors declare that there were no conflicts of interest.The authors thank the Federal University of Lavras and the CAPES for the master’s scholarship.

Answer 71

The main findings of this study are that AA-HTS (1) wassuccessfully performed in all joints, (2) was not associatedwith significant damage to intra-/extra-articular struc-tures, but (3) was associated with a high rate of intrao-perative complications (5 of 14 joints), ACI (10 of14 joints) (albeit minor in most cases) and techniquedeviations (7 of 14 joints). Despite this high rate of devia-tions, 12 of 14 femoral head tunnel exit points werelocated completely within the fovea capitis.Our first hypothesis was that it would be possible toperform AA-HTS in all joints. No previous peer-reviewedstudies describe hip arthroscopy or AA-HTS in cats. Thishypothesis was based on the fact that feline hip arthros-copy is reported to be possible to perform in a primary sur-gical textbook,13and a technique similar to that employedin this study was successfully performed in a canine clini-cal case.8Overall, our results provide evidence that it ispossible to perform AA-HTS in feline cadavers.We hypothesized that AA-HTS would not be associ-ated with significant damage to intra-/extra-articularstructures. No in vivo or ex vivo studies have evaluateddamage to intra-/extra-articular structures followingfeline open-HTS. In a canine ex vivo study,14positioningof periarticular structures (sciatic nerve, caudal glutealFIGURE 8 Gross dissection image demonstrating linearcartilage damage (white arrow) on the cranioventral aspect of theacetabulum after application of India ink. Dorsal is to the top of theimage and cranial is to the right.860 ESPINEL RUP /C19EREZ ET AL . 1532950x, 2023, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.13942 by Vetagro Sup Aef, Wiley Online Library on [30/08/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licenseand lateral circumflex femoral artery) relative to arthro-scopic portals using a technique similar to ours was eval-uated. Similar to our study, the sciatic nerve in that studywas close to the arthroscopic portal (mean 9 mm caudalto arthroscope portal, range, 6-15) but without injurythereto or any other periarticular structures.14In ourstudy, gross dissection of intrapelvic structures identifiedall toggles positioned a few millimeters dorsal to theobturator nerve without injury in any case. As far as weare aware, positioning of the toggle relative to obturatornerve has not been described previously. Acetabular tun-nel and toggle placement excessively ventral could poten-tially cause impingement of the nerve in cats. In a caninecase report,15severe pain was associated with bilateralimpingement of the obturator nerve with callus associ-ated with the free section of the pubic bone after bilateraltriple pelvic osteotomy. In our study, minor (<10% articu-lar surface) ACI involving the acetabulum or femoralhead was identified in 10 of 14 joints and the clinical sig-nificance of this is uncertain. Some degree of ACI mayhave occurred during LHF transection, therefore poten-tially overestimating the true rate of ACI associated withAA-HTS. In a canine ex vivo study in which the femoraltunnel was created using fluoroscopic anteversion andinclination angles,16femoral head ACI was detected in9 of 12 joints. No previous studies compare ACI followingopen or AA-HTS in dogs or cats. In a canine ex vivostudy comparing ACI injury following medial parapatellarmini-arthrotomy versus arthroscopy,17ACI was identifiedin 92.9% stifles that underwent arthroscopy compared with28.6% joints that underwent mini-arthrotomy. Despite this,stifle arthroscopy is associated with reduced short-termpostoperative morbidity compared with open arthrot-omy.18Further feline studies are required to compare out-comes and degree of ACI associated with open versusAA-HTS.No feline in vivo studies evaluated the rate of devia-tions associated with open-HTS. Our third hypothesiswas that AA-HTS would be associated with a low rate oftechnique deviations. This was not supported by theresults of our study, with deviations from the plannedpreoperative technique identified in 7 of 14 joints, all ofwhich were related to femoral bone tunnel creation.Despite this, the overall rate of deviations in our studywas lower than in previous canine cadaveric studies.16,19In 1 study in which femoral bone tunnels were createdbased on fluoroscopic anteversion and inclination angles,9 of 12 tunnels did not exit at the fovea capitis.16Inanother canine cadaveric study,19using a patient-specific3D-printed drill guide, the femoral bone tunnel exitedpartially outside the fovea capitis in 12 of 19 joints andcompletely outside in 4 joints. Conversely, despite theoverall high rate of deviations related to femoral bonetunnel creation in our study, 12 of 14 femoral head tun-nel exit points were located at the fovea capitis, with1 partially outside the fovea capitis and the othercompletely outside the fovea capitis. In both femurs ofcadaver 1, the femoral tunnel exited ventral to the foveacapitis. In subsequent cats, the guide tip was placed justdorsal to the fovea capitis instead of directly over its cen-ter, with elimination of this deviation in subsequentcadavers. Due to the small size of the feline coxofemoraljoint and the relatively large size of the pointed tip of theaiming device, particular attention was given in our studyto making certain with arthroscopic visualization that thetip did not move during manipulation of the extra-articular component of the guide in preparation for dril-ling. Breach of the caudal femoral cortex into the inter-trochanteric fossa was identified in 4 femurs, likelybecause the femoral tunnel was started too caudally. Theideal lateral femoral cortex tunnel entry point in our studywas at the level of the third trochanter, with no breach ofintertrochanteric fossa identified when the tunnel wasstarted at this ideal position. All cases of breach of the cau-dal femoral cortex into the intertrochanteric fossa wereclassified as major deviations because of the potentiallysevere postoperative implications of this deviation, includ-ing the increased risk of femoral neck fracture. These devi-ations highlight the importance of correct positioning offemoral tunnel entry and exit points. No deviations relatedto acetabular tunnel were identified in our study. Therate of deviations related to acetabular bone tunnel crea-tion has previously been reported as 0-37.5%.16,19,20Inthose studies,16,19,20the acetabular bone tunnel was cre-ated without arthroscopic visualization.Toggle passage through the femoral tunnel was themost frequent difficulty in our study, recorded as mildlydifficult in 6 joints. A toggle inserter was not commerciallyavailable for the toggle used here and the toggle had to becarefully passed through both tunnels attached to the pass-ing needle available with the kit. In 1 hip, the toggle disen-gaged and became lodged within the femoral tunnel. Thiscould likely have been avoided had a commercially avail-able toggle inserter been available. In 1 report in whichintra-articular toggle detachment occurred,8the toggle hadto be manually inserted through the acetabular tunnelusing an arthroscopic grasper and meniscal probe. Numer-ous other minimally invasive techniques are described fortoggle passage in previous reports.7,8,19 –21A number of intraoperative complications occurred inour study including cranial and dorsal misplacement of ak-wire in the femoral head on first attempt, unintentionalacetabular tunnel creation in 1 joint, and inadvertentover drilling of the k-wire without advancement of the k-wire through the acetabular fossa. None of these compli-cations was considered likely to affect patient outcome inESPINEL RUP /C19EREZ ET AL . 861 1532950x, 2023, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.13942 by Vetagro Sup Aef, Wiley Online Library on [30/08/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensea clinical case. In a previous ex vivo study in which inves-tigators used fluoroscopy to guide k-wire insertion fromthe lateral femur to fovea capitis, the k-wire bent duringplacement in 3 joints, either at the femoral neck or intra-articularly.21Shearing of the k-wire occurred during sub-sequent drilling at the location of the bend, resulting inthe need to abort the procedure.21This complication wasnot encountered in our study. We believe that the rate oftechnique deviations, intraoperative complications andACI may be reduced with greater experience in perform-ing AA-HTS in cats and this is supported by the fact thatno deviations, complications or ACI were identified inthe last 4 joints operated. This highlights the importanceof undertaking training in cadavers prior to performancein clinical cases.Limitations include the ex vivo nature of the study,with a relatively small number of cadavers. The clinicaloutcome including postoperative complications could notbe evaluated and this warrants further in vivo studies. Inclinical cases, tearing of the joint capsule may make cap-sular distension difficult and result in extravasation oflavage fluid as well as a potentially greater tendency forreluxation during the procedure resulting in a more tech-nically demanding procedure and greater ACI. The tech-nique also requires a reduced hip. Traction that wasapplied to the limb could potentially result in luxation inclinical cases. Such factors could result in a higher rate ofcomplications than observed in our study. Clinically nor-mal cats were included herein and therefore the timetaken to perform the approach and complete exploratoryarthroscopy was short and may not be reflective of theclinical situation with traumatic disruption of normalanatomy. It is possible that some ACI identified hereinmay have been related to ultrasound-guided LHF tran-section rather than the AA-HTS procedure, however, ACIassociated with the former tended to be manifested as linearcuts with minimal collateral cartilage damage. We attemptedto manually luxate the coxofemoral joint of a feline cadaverprior to performing this study and it resulted in proximalfemoral fracture rather than hip luxation. While arthroscopicLHF transection may have been possible, we believe that thismay have been associated with greater ACI due to the smallworking space in the feline hip.Compared with open-HTS, a slightly larger femoraltunnel is required for toggle passage with AA-HTS. Thisis because the toggle has to be inserted from lateral tomedial instead of inserting it through the acetabular tun-nel and passage of the strands of ultrahigh molecular-weight polyethylene from the fovea capitis to the lateralfemoral cortex. This has several important implicationsfor the AA-HTS technique including decreased marginfor error, increased risk of ACI, greater risk of femoralfracture because of weakening of the femoral neck, andpotentially more serious consequences in the event ofmisplacement.The results of our study suggest that feline AA-HTS isfeasible in feline cadavers but was associated with a highrate of minor ACI, intraoperative complications and tech-nique deviations. Despite the high rate of minor ACI,some of which may have been related to preoperativetransection of the LHF, a very high rate of femoral headtunnel exiting at the fovea capitis was identified in thisstudy. Care should be taken to avoid acetabular tunnelcreation and toggle placement excessively ventral, whichcould potentially result in impingement of the obturatornerve in cats. The clinical benefits of AA-HTS over anopen approach are currently unknown. Further studiesare required to confirm our results in clinical cases.ACKNOWLEDGMENTSAuthor Contributions: Espinel Rupérez J, LV, MSc,PhD: Conception of the study; study design and execution;acquisition of data; drafting, revision, and approval of thefinal manuscript. Serrano Crehuet T, DVM: Study design;drafting, revision, and approval of the final manuscript.Hoey S, MVB, DECVDI, DACVR: Study design; perfor-mance and review of CT examinations; drafting, revision,and approval of the final manuscript. Arthurs GI, MA,VetMB, PGCertMedEd, DSAS (Orth), FHEA: Studydesign; drafting, revision, and approval of the final manu-script. Mullins RA, MVB, DVMS, PGDipUTL, DECVS:Conception of the study; study design and execution;acquisition of data; drafting, revision, and approval of thefinal manuscript. Open access funding provided by IReL.CONFLICT OF INTERESTThe authors declare no conflicts of interest related to thisreport.ORCIDJorge Espinel Rupérez https://orcid.org/0000-0003-3170-9306Tomas Serrano Crehuet https://orcid.org/0000-0003-1588-5676Seamus Hoey https://orcid.org/0000-0003-1049-7658Gareth I. Arthurs https://orcid.org/0000-0003-4571-2610Ronan A. Mullins https://orcid.org/0000-0003-1159-2382

Answer 72

Positive-contrast arthrography with multidetector com-puted tomography demonstrated clinically useful sensi-tivity and specificity for identification of meniscal lesionsin this population, but our likelihood ratios while moder-ate in strength did not reach the predetermined thresh-olds of ≥10 and ≤0.1. Our hypothesis could only bepartially accepted. We found evidence of an effect ofobserver experience and a training effect during thisstudy.Sum values of 1.59 –1.63 for reading one, and 1.81 –1.85 for reading two, suggest that CTA is a useful test fordiagnosing meniscal lesions, particularly given the inci-dence of diagnosed meniscal damage here.28The likeli-hood ratios suggest that a positive CTA finding gives amoderate to large increase in the likelihood of meniscallesions being present, whereas negative findings give alarge decrease in this likelihood. Use of CTA appears tobe symmetric, favoring neither positive nor negativediagnoses.Test performance is defined in relation to the refer-ence standard. Diagnoses in this study were achievedusing arthrotomy, probing and visual inspection by anexperienced orthopedic surgeon. This modality was usedas the sole reference standard in some24or all22of dogsassessed in previous clinical CTA studies. Arthroscopy isconsidered superior to arthrotomy for the diagnosis ofmeniscal lesions,7,16although even arthroscopy may misssome lesions due to inability to evaluate the internalstructure of the meniscus.23,34False positive CTA diagno-ses might therefore reflect inability to correctly confirm ameniscal lesion rather than a real test failure. While ourresults can thus be compared with previous CTA studies,it remains possible that test performance is overstated incomparison to using arthroscopy as the referencestandard.While all stifles in this study underwent surgicalexploration, if CTA is to be used as a screening tool thenarthrotomy or arthroscopy will not necessarily be per-formed. Our results indicate that when postliminary tearsare suspected less than one in five dogs will have a teardespite a negative reading, and that for first-presentationdogs, less than one in 14 will have tears with a negativereading. These values will change depending on theactual clinical probabilities of meniscal lesions indifferent patient populations-with rates of 0% –84.6%reported in a systematic review35- and clinicians shouldtherefore make an informed estimate of likely post-testprobabilities. For comparison, analysis of data fromcadaver studies with simulated meniscal lesions yieldedpositive and negative likelihood ratios of 21.3 and 0.16,36and 16.0 and 0.21,16for arthroscopic examination withprobing. Arthroscopy with probing will thus give higherpositive post-tests probabilities for meniscal injury thanCTA in our population, but the negative post-test proba-bilities would be worse at 32% –39% for postliminary tearsand similar at 13% –16% for the first-presentation. Finally,the client should be fully informed of the potential risksand benefits of each course of action.There was a clear effect of experience, both in termsof test performance between observers 1 and 2 andobserver 3, but also in terms of continued learningthrough the study period despite a training protocolimplemented before starting this study. The mix in abili-ties probably contributed to the moderate interobserverkappa value obtained in the first reading. The trainingprotocol used was similar to one previously reported forboard-certified radiologists with limited experience ofCTA,24with our inexperienced observers achieving simi-lar sensitivity and specificity to theirs. This may indicatethe advantages of multidetector technology on imagequality. Similarly limited training materials were used inanother study by two board-certified radiologists and aboard-certified surgeon.22This second study included arepeat reading by one observer, with an apparentimprovement in performance. The significant improve-ment in performance noted for the two inexperiencedobservers in our study indicates that the training protocolwas insufficient to achieve clinical competence, and thatprevious studies' results may have been hampered bythis. It is possible that further improvement might havebeen noted in a third reading. The reasons for improve-ment given that no information on correct diagnosis wasavailable to the observers may be due to improved famil-iarity with multiplanar reconstruction, stifle anatomy,and use of imaging software during the intensive readingperiod.Alternative modalities for meniscal lesion diagnosisinclude ultrasonography and MRI. Reported sensitivityand specificity for canine meniscal lesion diagnosis are82%–90% and 93%, respectively, but is highly dependenton the equipment and operator.10,19In humans, themodality of choice is MRI, with a diagnostic accuracy of86%–91% and sensitivity and specificity for medial menis-cal tears of 91% –93% and 81% –88%, respectively.37,38Sim-ilar findings were reported in dogs with cranial cruciateligament disease.20,21Availability of veterinary MRI facil-ities remains limited, scanning costs are high, and scan80 KNUDSEN ET AL . 1532950x, 2024, 1, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.13982 by Cochrane France, Wiley Online Library on [05/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensetimes are longer in comparison to multidetector CT, andMRI image quality is reduced adjacent to metal implants,limiting applicability for late meniscal injury. Addition-ally, MRI requires full anesthesia while CT may be per-formed under sedation. Our results compare favorably tothe above modalities and given the wider availability ofCT and of radiological reporting services, multidetectorCTA appears to be a promising diagnostic tool for identi-fying meniscal lesions in dogs. Clinicians should considerthe cost –benefit ratio of these diagnostic modalities inlight of local costs. While arthroscopy remains the refer-ence standard, the costs of this procedure include timeinvolved in setting up and removing equipment, proce-dure time, which impact total anesthesia time for sur-gery, as well as technician time for cleaning andsterilizing for subsequent use.We found that the positioning protocol used here forscanning, with the tibial plateau positioned approximatelyvertical and thus parallel to the plane of the scanner,resulted in implants (if present) being imaged in slices dis-tant to the structures of interest. As a result, we did notexperience any problems with overlap apart from one ofthe excluded dogs with a lateral fabellar suture crimp over-lying the joint space. Previous clinical experience hadshown that failure to position appropriately can result inthe native scan including part of a plate or cage in theslices covering the meniscus, giving significant artifacts.We elected to exclude patients with an interval fromscanning to surgery exceeding 14 days. While most dogswere operated the day of scanning, both practice andowner scheduling conflicts caused a delay in some cases.It is logical to assume that the longer the stifle jointremains unstable, the greater the chance that the medialmeniscus will incur an injury, and that greater intervalsmight risk development of a meniscal lesion in a menis-cus previously scanned and assessed to be normal. Weare not aware of solid epidemiological data on this point,and 14 days was arbitrarily selected as a cut-off.Of the stifles suspected of postliminary tears, themajority had previous tibial tuberosity advancement sur-gery, reflecting the popularity of this procedure regionallyand within the first author's practice. While later caseswere primarily operated with tibial plateau levelingosteotomy, the follow-up times between for the two pro-cedures were not equivalent, and it would be inadvisableto draw conclusions from this population.This study has some additional limitations. The inter-val between scanning and surgical exploration was incon-sistent, due to a combination of clinical scheduling issues,owner expectations and wishes, economics, and clinicalurgency. Some dogs may have developed meniscal lesionsafter scanning, and the possibility of this could increasewith increasing interval to surgery. Follow-up was at least6 months postoperatively, but cases may have been lost tofollow-up, or have had occult lesions at surgical explora-tion which became apparent after this time. Surgicalexploration was not blinded, as one observer was the leadsurgeon. Although subsequent measurements for the pur-poses of this report were performed in a blinded fashion,there remains a possibility of bias at the initial surgicalevaluation. The volume of contrast medium used was sub-jectively based on joint distension, which could risk over-or underdosing and consequent obscuration or loss ofdetail in the images. However, no leakage was noted, andcontrast detail appeared subjectively good in all cases.Standardization of injection volume to body mass or sur-face area might be considered in the future. No pain orother adverse effects were noted following contrast injec-tion, but pain is listed as a common adverse effect ofarthrography in people with the product used: this mayhave been masked by concurrent sedation and administra-tion of analgesics in our population. The effect of experi-ence and apparent improvement in identification ofmeniscal lesions during the study period indicates thatlonger periods of training and familiarization are neces-sary for similar studies and for clinical proficiency.4.1 |Clinical significanceMultidetector CTA can be considered for assessment ofmedial meniscal integrity in dogs due to clinically usefulsensitivity and specificity, and moderate likelihood ratios.Extensive familiarization with and training on CTAimages are recommended prior to clinical use.AUTHOR CONTRIBUTIONSKnudsen L, DVM, MS CACS (Diagnostic Imaging): Con-ception and design, data acquisition and analysis, draft-ing of manuscript. Østergaard E, DVM: Data acquisition,analysis and drafting. Jensen JJ, DVM: Data acquisitionand analysis. Miles JE, BSc, BVetMed, PhD; Design, anal-ysis, and critical revision of the manuscript. Buelund LE,DVM, PhD: Design, and critical revision of the manu-script. All authors gave their final approval.ACKNOWLEDGMENTSWulffeld, M.M. RVN NCert (DI) for technical assistancewith the CT arthrography.FUNDING INFORMATIONNone declared.CONFLICT OF INTERESTThe authors declare no conflict of interest related to thisreport. Preliminary results are presented as part of theKNUDSEN ET AL . 81 1532950x, 2024, 1, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.13982 by Cochrane France, Wiley Online Library on [05/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensequalification process for the DVM degree (EsbenØstergaard and Jakob J. Jensen) and MS degree (LarsKnudsen) at University of Copenhagen.ORCIDJames E. Mileshttps://orcid.org/0000-0002-4377-1572Lene E. Buelund https://orcid.org/0000-0002-4730-4111

Answer 73

The results of this study support our hypothesis that the S-sign is more effective than the Klein’s line and modified Klein’s line for the diagnosis of SCFE in cats. Excluding cases of fully displaced FCE, the S-sign on the VD frog-leg radiographs more accurately diagnosed SCFE than the S-sign on the VD extended-leg radiographs and the Klein’s line (92.4% vs 88.8% vs 60.6%, respectively), and had the greatest sensitivity (93.9% vs 79.2% vs 30.6%, respectively). The S-sign on the VD extended-leg radio -graphs had greater specificity than the Klein’s line and S-sign on the VD frog-leg radiographs (99.2% vs 97.9% vs 90.9%, respectively). The modified Klein’s line detected SCFE in 40.2% of cases that were negative for Klein’s line. In addition, intra-observer and inter-observer reliabili-ties were greatest for the S-sign in both VD extended-leg and frog-leg views with almost perfect agreements. In comparison, intra- and inter-observer reliabilities for the Klein’s line were fair and moderate, respectively, and were both moderate for the modified Klein’s line.The S-sign in the frog-leg lateral pelvic view in humans has produced very favourable results for the diagnosis Table 4 The mean results from each round of readings from each of the observers when the fully displaced femoral capital epiphyses control group was excluded from the analysisKlein’s line Modified Klein’s line S-sign extended S-sign frog-leg Round 1 Round 2 Round 1 Round 2 Round 1 Round 2 Round 1 Round 2AccuracyObserver 1 50.0 58.0 29.4 35.7 80.0 80.0 86.0 90.0Observer 2 80.0 50.0 64.3 53.8 92.0 86.0 94.0 92.0Observer 3 62.0 70.0 66.7 30.8 94.0 88.0 94.0 92.0Observer 4 64.0 58.0 64.7 64.7 92.0 92.0 96.0 92.0Observer 5 62.0 52.0 52.9 41.2 92.0 92.0 94.0 94.0SensitivityObserver 1 11.5 28.6 18.2 0.0 61.5 61.5 80.8 88.5Observer 2 61.5 46.2 62.5 44.4 84.6 73.1 96.2 96.2Observer 3 30.8 42.3 75.0 0.0 88.5 76.9 96.2 96.2Observer 4 30.8 19.2 60.0 54.5 84.6 84.6 96.2 96.2Observer 5 26.9 7.7 54.5 33.3 88.5 88.5 96.2 96.2SpecificityObserver 1 91.7 95.5 50.0 100.0 100.0 100.0 91.7 91.7Observer 2 100.0 95.8 66.7 75.0 100.0 100.0 91.7 87.5Observer 3 95.8 100.0 57.1 66.7 100.0 100.0 91.7 87.5Observer 4 100.0 100.0 71.4 83.3 100.0 100.0 95.8 87.5Observer 5 100.0 100.0 50.0 60.0 95.8 95.8 91.7 91.7Positive predictive valueObserver 1 60.0 88.9 40.0 0.0 100.0 100.0 91.3 92.0Observer 2 100.0 92.3 71.4 80.0 100.0 100.0 92.6 89.3Observer 3 88.9 100.0 66.7 0.0 100.0 100.0 92.6 89.3Observer 4 100.0 100.0 75.0 85.7 100.0 100.0 96.2 89.3Observer 5 100.0 100.0 66.7 66.7 95.8 95.8 92.6 92.6Negative predictive valueObserver 1 48.9 51.2 25.0 35.7 70.6 70.6 81.5 88.0Observer 2 70.6 48.9 25.0 37.5 85.7 77.4 95.7 95.5Observer 3 56.1 61.5 35.0 36.3 88.9 80.0 95.7 95.5Observer 4 57.1 53.3 30.0 50.0 85.7 85.7 95.8 95.5Observer 5 55.8 50.0 38.1 27.3 88.5 88.5 95.7 95.7Data are %8 Journal of Feline Medicine and Surgery of SCFE, with an accuracy, sensitivity and specificity of 92.4%, 89.0% and 95.2%, respectively.19 For the purpose of this study, we analysed the S-sign in both VD extended-leg and VD frog-leg views. For both views, our results when the fully displaced FCE cases were excluded are similar to those found in this human study. It is also useful to find good results with this method in the VD extended-leg view and this will be particularly useful in cases where only one of these radiographic views is avail-able for interpretation.Excluding the fully displaced FCE control group, the accuracy and sensitivity of the Klein’s line in the present study were lower than those reported in the human litera-ture at 60.6% and 30.6%, respectively, but specificity was higher at 97.9%. The Klein’s line has shown variable suc -cess in the identification of SCFE in humans. Two studies found it had poor sensitivity, with one study reporting a sensitivity of 39% from 23 cases,17 and another report -ing a sensitivity of 40.3% from 30 cases.18 A more recent study found greater success with the Klein’s line, with an accuracy of 79.2%, sensitivity of 68.3% and specificity of 89.0% across 35 patients. In the human literature, it has been described that the FCE initially displaces posteriorly before it then displaces medially, which is why epiphy -seal displacement is often missed on an AP pelvic radio -graph and is why the Klein’s line has poor sensitivity as it will only detect medial displacement.16,17 It is possible that this same pattern and progression of FCE displace -ment occurs in cats.In our study, the modified Klein’s line produced a sensitivity of 40.2%, but it must be appreciated that any cases with positive Klein’s line results, or that were bilat -erally affected, were not included in the analysis of this method. Therefore, it is more accurate to consider that the modified Klein’s line in this study identified SCFE in 40.2% of the unilaterally affected cases that were not diagnosed via the Klein’s line method. The modified Klein’s line was developed to improve the sensitivity of the Klein’s Line.18 In comparison to the Klein’s line, the human literature reports that the modified Klein’s line has shown an improvement in sensitivity from 40.3% to 79.0%,18 and from 39% to 87%.19 Due to the differ -ences in size between humans and feline patients, the difference of > 2 mm required for a positive in humans was too high. Instead, we decided to use a difference of ⩾0.5 mm. Further research could be carried out to determine whether this value is appropriate, or whether a better value exists in order to achieve an optimum balance between sensitivity and specificity. It is impor -tant to appreciate that using the Klein’s line or modi-fied Klein’s line methods alone may potentially miss a bilateral SCFE presentation. As an example, for the bilat-eral cases in this study, the Klein’s line only detected 41.7% of positive hips in round 1 and 30% in round 2. The modified Klein’s line requires one hip to be normal, and so use of this test in bilateral cases is inappropriate. However, you may not know whether a case is unilater -ally or bilaterally affected, which limits the usefulness of this test.Various definitions of the Klein’s line exist in the human literature. It is most commonly described as a line drawn along the superior margin of the femoral neck on an AP radiograph.11,18,19 This definition cannot be applied to our cat population because the superior margin of the femoral neck in humans is much straighter than the much more concave superior margin of the femoral neck in cats. An alternative definition in human literature defines the Klein’s line as the tangent to the concavity on the supe -rior margin of the femoral neck.16,21 Owing to the con-cavity that exists in our feline population, we chose to adopt the latter definition in this study. This concavity may explain why the intra- and inter-observer reliabilities were lower for the Klein’s line and modified Klein’s line than the other methods, because there may be different interpretations of where the proximal and distal points of the lateral femoral neck lie. In addition, appreciation of where the tangent lies on a non-perfect curvature is likely to vary among observers. Periosteal reactions to the femoral neck can also obscure determination of where the tangent should lie.There are several limitations to this study. The sample size is small and so a greater number of cases could be analysed in the future, preferably where each diagnostic method is tested on a large number of mildly affected cases, as this is when these diagnostic tools will be most useful. The determination of the position of the Klein’s line is likely to have varied between observers. The deci -sion to use 0.5 mm for the modified Klein’s line test was not based on any scientific testing, and so further research could also be directed to finding the most accurate value to use. The quality of patient positioning for the radio -graphs also varied between cases, with pelvic rotation, degree of hindlimb rotation, and angle of flexion and extension differing among cases.ConclusionsThis is the first published report describing the use of the Klein’s line, modified Klein’s line and S-sign to detect SCFE in cats. The S-sign in both VD extended-leg and VD frog-leg views produced results with high reliability, sensitivity, specificity, and positive and negative predic -tive values for detection of SCFE in cats. The S-sign can be used to increase early diagnosis and treatment in cats with SCFE that have only subtle radiographic changes. The use of the Klein’s line to detect SCFE in cats would not be recommended by the authors. The modified Klein’s line did show some merit by detecting 40% of SCFE cases that were not detected via the Klein’s line, but caution must be taken to avoid missing bilateral cases.Butts et al 9Acknowledgements The authors would like to thank all owners, referring veterinarians and radiographers for their assistance with providing cases and radiographs for this study.

Answer 74

In this study, 3 gastrotomy suture patterns were compared, and all dogs were discharged after hospi -talization. A 1-month monitoring period revealed a 100% survival rate with no major complications. No significant differences were detected among the 3 groups in terms of survival time or the absence of major complications. No major complications arose, and if they had occurred, the study would have been discontinued. We validated our hypothesis that no major complications would occur after using a full-thickness, single-layer, simple, continuous pattern. The gastric blood supply’s robustness, collateral circulation, and good surgical practice make dehis -cence a rare occurrence with gastrotomy, instead promoting effective healing after gastric injury.The arterial blood supply to the stomach, origi -nating from the celiac artery and branching into the splenic, hepatic, and left gastric arteries. Branches from these parent tributaries supply blood to specif -ic gastric regions; these tributaries then anastomose to provide collateral circulation.1 These results sug -gest that single-layer gastrotomy sutures are safe. No relationship was found among the 3 groups and the number of minor complications reported.The use of a single-layer pattern has been re -ported in a previous experimental study on canine stomachs without lesions.4 In this previous study, a series of 25-mm-long gastrotomy incisions were cre -ated using an electro scalpel and sutures were ap -plied using a 3-0 synthetic absorbable monofilament suture or a 3-0 barbed device. Dogs were euthanized on either day 3, 7, or 14 postoperatively. Immediate -ly after euthanasia, each gastrotomy site was then isolated and burst tested, which showed no leakage even at pressures of up to 250 mm Hg (ranged from 9 to 75 mm Hg in the canine stomachs).6 Therefore, even if suture strength may appear to be important during the first 3 days postoperatively, the healing process is well advanced after 7 days. During the 1-month monitoring period, we checked the dogs long after the stomach had healed, and we believe that no leakage could occur after this time. Stomachs heal within 7 days in rats; therefore, the 1-month monitoring period should be long enough to identify any major complications.7Two surgeons participated in this study, which might have introduced some variability in the out -comes, but no relationship was found between the surgeons and the rate of minor complications report -ed (P value = .375), and no major complications arose.Single-layer gastrotomy sutures are expected to result in shorter anesthesia times (although we did not assess this), reducing the risk of infection.8 However, histologic examinations to provide details about healing were beyond the scope of this study due to ethical reasons.In an ex-vivo experimental study, Duffy et al9 compared a double-layer suture with a single-layer suture for closing gastrectomies in dogs. The dou -ble-layer suture pattern for canine partial gastrec -tomy exhibited superior biomechanical properties compared to single-layer suture. Their results did not support the use of single-layer sutures for gastrecto -mies; when using staples at least.9This study had some limitations. Only 60 dogs were included, which might have resulted in type II errors. Postoperative complications after gastrosto -my are uncommon, and information in the literature is scarce. No data on survival time or major compli -cations have been reported in veterinary medicine. In human medicine, complications occur in 4.2% of stomach surgeries.10 Given this low incidence and the scale of our study, it was not realistic to include a population of 5,020 individuals, which would have been required to reach a statistical power of 80% and an odds ratio of 1.5 using such an incidence rate.We did not assess the strengths of the differ -ent gastrotomy closure methods, as doing so would have required invasive methods, which was beyond the scope of our study. Our monitoring period was sufficient to detect any major complications, as the healing period for stomach surgeries is less than 7 days according to experimental studies in rats.4,7Retrospectively, minor complications did arise and were reported for 8 dogs. All these complica -tions were associated with celiotomy and not with gastrostomy. Minor complications included those that did not require hospitalization or further sur -gery. In all 34 dogs with data on minor complications available, no direct link was identified between the minor complications and the gastrotomy pattern. An earlier visit with a clinical examination within 5 days of surgery might have revealed some discreet discomfort during this period.Our study included dogs with uncomplicated gastric foreign bodies, whereas gastrotomy is some -times performed after perforation of the gastric or intestinal wall by a foreign body. In such situations, Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 01/27/24 05:24 PM UTC 5septic peritonitis will be present perioperatively, and the subsequent gastric serosa inflammation and de -layed closure in a septic environment could modify the healing capacities. In 38% of cases, dogs under -going gastrointestinal surgery with preoperative peritonitis developed postoperative peritonitis, com -pared to only 6% when it was absent preoperatively. In this study, 15 out of 45 dogs died due to this con -dition. When all surgeries were considered, common risk factors for the development of septic peritonitis included preoperative septic peritonitis.11 Therefore, in cases with septic conditions, double-layer sutures are likely recommended.In conclusion, single-layer sutures offer a safe alternative for gastrotomy sutures, with no major complications. A similar study on a larger population of dogs would be necessary to confirm our findings.AcknowledgmentsNone reported.DisclosuresThe authors have nothing to disclose. No AI-assisted technologies were used in the generation of this manuscript.FundingThe authors have nothing to disclose.

Answer 75

This study revealed that some sti ﬂes with MPL have func-tional patella alta, the condition wherein the patella is placedmore proximal than the reference range of sti ﬂes withoutMPL when the sti ﬂe joint is at full extension. Functionalpatella alta was associated with a larger extension angle ofthe sti ﬂe joint but also contributed by longer PLL and shorterTL.Patella alta has been discussed in relation to MPL in dogs.1–8Although studies have shown that patella alta is not associatedwith MPL in small breed dogs,4,9,10,14none of them consideredthe range of motion of the sti ﬂe joint. This study showed thatsome dogs with MPL had their patella placed more proximallythan dogs without MPL when the sti ﬂej o i n tw a sa tf u l lextension. Wangdee and colleagues suggested that the patellamight exceed the trochlea proximally during sti ﬂej o i n th y -perextension even with normal PLL/PL in a study on Pomera-nian dogs with bidirectional patella luxation and described itas functional patella alta.10Although this study did not focuson de ﬁning hyperextension of the sti ﬂe joint, it was concludedthat functional patella alta could occur with full extension ofthe sti ﬂe joint. Considering that 11 of 12 dogs with functionalpatella alta were in the MPL group, it might be a risk factor forMPL. Full extension of the sti ﬂe joint does not usually occurduring walking or trotting.19–22A kinematic analysis of Grey-hound dogs showed that the sti ﬂe joint angle during somemovement in the initiation period was extended as the maxi-mum passive range of motion.16,23However, kinematic analy-ses of the usual motions of dogs are still lacking, and it isunknown whether their sti ﬂes extend fully during other dailyactivities.Table 1 Stiﬂej o i n ta n g l e ,P L L / P L ,T L / P L ,T L / F C ,A Ta n g l e ,P P Pand DPP in the MPL and control groupsMPL group Control groupStiﬂe joint angle 145 ( /C611) 141 ( /C69)PLL/PL 1.88 ( /C60.22) 1.93 ( /C60.21)TL/PL 1.47 ( /C60.16) 1.58 ( /C60.16)TL/FC 1.62 (1.32 –2.13) 1.75 (1.29 –2.06)AT angle 138 ( /C66) 138 ( /C66)PPP /C00.29 (/C60.15) /C00.16 (/C60.14)DPP 0.35 ( /C60.14) 0.45 ( /C60.13)Abbreviations: AT angle, anatomical tr ochlear angle; DPP, distal patellarposition; PLL/PL, patellar ligament length to patellar length ratio; PPP,proximal patellar position; TL/FC, trochlear length to size of femoracondyle ratio; TL/PL, trochlear length to patellar length ratio.The sti ﬂe joint angle, PLL/PL, TL/PL, AT angle, PPP and DPP are shown asthe mean value ( /C6standard deviation). The TL/FC is shown as themedian value (range).Table 2 The results of simple logistic regression for patella alta and the sex, limb side, body weight, age, condition of tibialtuberosity physis, joint angle, PLL/PL, TL/PL, TL/FC or AT angleCoefficient p-Value 95% CISexRef. CastratedSpayedMaleFemale0.7730.08000.1670.3150.9330.861/C00.735 –2.28/C01.78 –1.94/C01.70 –2.03Limb sideRef. LeftRight 1.19 0.087 /C00.171 –2.54Body weight 0.155 0.092 /C00.0254 –0.336Age /C00.000898 0.0750 /C00.00189 –0.0000922Tibial tuberosity physisRef. ClosedOpen /C00.546 0.432 /C01.91 –0.815Joint angle 0.224 <0.001 0.113 –0.335PLL/PL 4.44 0.006 1.28 –7.60TL/PL /C03.75 0.059 /C07.64 –0.141TL/FC /C04.93 0.025 /C09.24 –/C00.614AT angle 0.0541 0.317 /C00.0518 –0.160Abbreviations: AT angle, anatomical trochlear angle; CI, con ﬁdence interval; PLL/PL, patellar ligament length to patellar length ratio; Ref, reference;TL/FC, trochlear length to size of femoral condyle rat io; TL/PL, trochlear length to patellar length ratio.Table 3 The ﬁnal model for multipl e log regression forfunctional patella altaCoefficient p-Value 95% CIJoint angle 0.312 0.002 0.115 –0.509PLL/PL 15.0 0.005 4.44 –25.5TL/PL /C016.7 0.012 /C029.6 –/C03.71Cons /C055.0 0.004 /C092.6 –/C017.4Abbreviations: CI, con ﬁdence interval; Cons, constant; PLL/PL, patellarligament length to patellar length ratio; TL/PL, trochlear length topatellar length ratio..Logistic regression showed that several factors affectedthe occurrence of functional patella alta. A large extensionangle of the sti ﬂe joint, long patellar ligament and shorttrochlea length could lead to a more proximally placedpatella than the reference range. A previous study on theproximodistal patellar position in small-breed dogsshowed that the proximodistal patellar position was af-fected by the sti ﬂe joint angle, age, PLL/PL, TL/PL, TL/FC andAT angle.9However, variation in the age, TL/FC and ATangles did not induce functional patella alta. Age was notexpected to be an in ﬂuencing factor as its effect on PPP orDPP was only 1% per 17 months in a previous study.9Although an open physis could be the cause of the in ﬂu-ence of age, the condition of tibial tuberosity physis didnot affect the occurrence of functional patella alta in dogsolder than 6 months of age. The full extension of the sti ﬂecould cause the patella to ﬂoat slightly from the femoraltrochlea, which might cancel the effect of the trochlearangle and FC size.It was suggested in a previous study that using PLL/PLalone to diagnose patella alta might not be appropriate.9Similarly, this study does not recommend the diagnosis offunctional patella alta by PLL/PL alone because the AUC of theROC curve for PLL/PL was only acceptable, and the Youdenindex for the cut-off value was 0.34. The AUC of the ROC curvefor the sti ﬂe joint angle was excellent; thus, its use withPLL/PL to diagnose functional patella alta is suggested. Thisalso indicated that the leading cause of functional patella altais excessive sti ﬂe extension angle, but dogs having borderlineangle might develop functional patella alta with longer PLL orshorter TL. In humans, patellar tendon imbrication,24tibialtuberosity medialization,25patellar tendon advancement26and other procedures are performed along with tibial tuber-osity distalization to correct patella alta.27Some veterinarysurgeons transpose the tibial tuberosity distally to correctpatella alta with MPL in dogs.28–30Recently, cranial tibialwedge osteotomy and tibial plateau levelling osteotomy havebeen reported to distalize patellar position31and could be atreatment option for patella alta. With these several alter-natives, it might be bene ﬁcial to evaluate the speci ﬁc factorscausing patella alta in each case and choose the mostappropriate technique. However, the cut-off values in thisstudy were aimed at diagnosing functional patella alta andexceeding them would not con ﬁrm the cause of functionalpatella alta. For PLL/PL, the cut-off value in this study wassmaller than 2.51 (1), 2.0 (2) or 2.06 (5), values indicated inprevious studies as limits for patella alta. In some studies, thePLL was measured as a caudal aspect of the patellar ligament,which could potentially make the values smaller. However,the limits for patella alta measured with this method weredetermined to be 1.97 (7) or 2.0 (8), which were also greaterthan the cut-off value in this study. Using the cut-off value ofPLL/PL from the current study might lead to the overdiagno-sis of long patellar ligament.Fig. 4 Receiver operating characteristic (ROC) curve for the sti ﬂej o i n ta n g l e( A), patellar ligament length/patellar length (PLL/PL) ( B), andtrochlear length/patellar length (TL/PL) ( C). The area under the curve (AUC) of each factor is at the bottom left..This study had several limitations. The dogs were ofvarious breeds; thus, the present results might be a combi-nation of characteristics of the different breeds. Futureresearch on the proximodistal patellar position in singlebreeds is required to identify the trends within each breed.Another limitation of this study is that the sti ﬂe joint waspassively extended by the observer rather than activelyextended by the dogs themselves. The load to extend thestiﬂe joint was not measured objectively; therefore, it mighthave deviated slightly. However, the difference between theextended sti ﬂe angle of the right and left sides was a medianof 5 degrees (range: 0 –20), indicating a certain level ofconsistency. Further research on the proximodistal patellarposition during active sti ﬂe extension is required.In conclusion, mediolateral radiography of the sti ﬂej o i n tin full extension is clinically advantageous in dogs with MPLbecause some might have a proximally positioned patellathat is recognizable when the sti ﬂes are extended. Factorsassociated with this condition include a greater full exten-sion angle of the sti ﬂe joint, longer patellar ligament andshorter femoral TL. Consideration of the factors causingpatella alta could facilitate an appropriate selection of thesurgical technique for correction.

Answer 76

This study demonstrates the variability in histopatho-logic findings in cats with obstructions secondary to trichobezoars. Cats included in this study exhibited both acute and acute-on-chronic gastrointestinal signs.Histopathologic findings from at-T samples were noted to have an increased severity of inflammation compared with biopsy samples obtained elsewhere in the gastrointestinal tract. When excluding biopsies with his -topathological diagnosis suggestive of alimentary small cell lymphoma, 42.4% of the at-T biopsies demonstrated a severity qualifier of ‘marked’ or ‘severe’ inflammation. This contrasts significantly to the pre-T and post-T groups, which had severe inflammation noted in 8.3% and 12% of samples, respectively (P = 0.002). Similarly, mucosal erosion or ulceration was more common at-T. This find -ing, along with the increased severity of inflammation, is suspected to be secondary to shearing forces and direct trauma from attempted peristaltic advancement of the trichobezoar. The presence of severe inflammation and/or mucosal damage could obscure underlying intestinal pathology and thus confound evaluation for underlying chronic enteropathies.A neutrophilic component of inflammation was pre-sent in 18/100 (18%) biopsy samples, and when present, was significantly more likely to be obtained from at-T (P <0.001). Furthermore, all five histopathological diagno-ses of predominantly neutrophilic/suppurative enteritis were obtained from the at-T. This neutrophilic compo-nent is suspected to be secondary to acute, traumatic injury of the intestinal mucosa from the tricho bezoar. In fact, 66.7% of biopsies with a neutrophilic inflam-matory component were obtained from cats with acute clinical signs only. This was significantly more common than cats with chronic clinical signs ( P <0.001). Bacterial enteropathogens, such as Campylobacter species, some Enterobacteriacea, Bacteroides species and Clostridium species, have been shown to result in neutrophilic enteri -tis and gastrointestinal clinical signs.7,8 However, enteric bacteria can also be present in clinically healthy animals.8 Additional testing for enteric bacteria was not pursued in our study, likely because the clinical signs were attributed to the obstructive trichobezoar.A comparison of pre-T and post-T samples showed similar frequencies of both type and degree of inflam-mation between groups (Tables 5 and 6). None of these samples showed evidence of mucosal erosion/ulcera-tion. No post-T biopsies exhibited predominantly neu-trophilic inflammation, which was anticipated given the lack of mucosal exposure to the trichobezoar aborad to the obstruction. However, only 2/26 intestinal biopsies obtained orad to the trichobezoar obstruction and were described as having a neutrophilic component that would commonly occur with acute inflammation. The unexpect-edly low incidence of neutrophilic inflammation in pre-T samples may be associated with the quick regenerative nature of the small intestinal mucosa, which fully regen -erates within 2–3 days.9 Although the duration of time elapsed between trichobezoar exposure of the intestinal mucosa and biopsy collection cannot be determined, it is possible the intestinal mucosa orad to the obstruction had gone through complete regeneration by the time of surgical intervention.It is worth noting that only 5/100 biopsies in this study showed no evidence of inflammation, and all of these were obtained pre-T. In contrast, no biopsies obtained aborad to the trichobezoar were diagnosed as ‘normal’ as all demonstrated histopathological changes. This may lead some to the conclusion that all cats in this study had some level of underlying enteropathy that may result in secondary intestinal obstruction. This confu-sion may stem from lack of understanding of ‘normal’ amounts of inflammatory cells within the gastrointesti-nal tract in cats. The most widely used gastrointestinal histopathology standards, released by the World Small Animal Veterinary Association (WSAVA) Gastrointestinal Standardization Group in 2008, were based on full- thickness biopsies obtained from specific pathogen-free colony cats aged 5–18 months.6 However, a recent study used WSAVA guidelines to evaluate endoscopic gastric and duodenal biopsies from clinically normal cats aged over 3 years, which were thought to more accurately represent the population demographics of cats present-ing for evaluation of chronic enteropathies. All 20 cats in that study had histopathological abnormalities, includ-ing 2/20 that were diagnosed with small cell lymphoma. While these two cats later developed clinical signs and were subsequently euthanized, 17/20 never showed any gastrointestinal clinical signs after a median time of 709 days.4 These findings highlight the need to evaluate biopsy results cautiously and in conjunction with clinical signs and response to treatment.The presence of lymphoplasmacytic and lympho-cytic/eosinophilic inflammation is potentially relevant in this study as these patterns of inflammation are com -monly seen in FCE (idiopathic inflammatory bowel disease (IBD), dietary hypersensitivities) and has been reported with intestinal lymphoma,5,10,11,12 all of which may predispose a cat to an intestinal obstruction. These inflammatory patterns are not specific, however, and the retrospective nature of this study precludes defini-tive diagnosis in our cats. Interestingly, long-haired cats have been described as over-represented in cases of feline gastrointestinal eosinophilic sclerosing fibroplasia, pos-sibly due to increased ingestion of hair and associated allergens.13 While no masses were noted in these cats, 6 Journal of Feline Medicine and Surgery ingestion of hair and the associated allergens could be considered an etiology for eosinophilic enteritis.Alimentary small cell lymphoma was diagnosed in 10/44 (22.7%) study cats and our findings suggest both chronicity of clinical signs and age should be considered when discussing diagnostic utility of additional gas-trointestinal biopsies during surgical intervention for trichobezoar obstruction. Cats diagnosed with alimen-tary lymphoma represented 41.7% of cats with chronic clinical signs (10/24) and cats diagnosed with alimentary lymphoma were also significantly older, with an aver -age of 12.9 years (vs 6.4 years for cats with inflammatory changes, P = 0.001). This finding is consistent with several studies that have noted the mean age in cats with alimen -tary lymphoma to be 12.5 years.14–16Histopathological diagnoses can vary between biop -sies obtained from different anatomic locations, as evi-denced in our study. A total of 26 cats had biopsies from two or more anatomic segments of the small intestine, and seven of these cats were diagnosed with alimentary lymphoma. Interestingly, 6/7 (85.7%) cats diagnosed with alimentary lymphoma showed complete agreement among a diagnosis of lymphoma between all small intes -tinal biopsies, which contrasts a recent study in which a diagnosis of lymphoma within both duodenal and ileal biopsies occurred in only 17% of the population.17 While the small population of this study was a potential limita -tion, it does not substantially differ from the number of cats diagnosed with lymphoma in the present study (18 and seven cats, respectively).Of 26 cats with two or more small intestinal biopsies, 19 had histopathology consistent with various inflam-mation, and complete histologic agreement occurred in 9/19 (47.4%) cats. Although our study demonstrated relatively high agreement between biopsies, the sample size and lack of standardization with biopsy location and number are considered potential limitations to this find -ing. Furthermore, biopsies from each cat were submitted and evaluated together, which could bias histopatho-logic interpretation owing to lack of blinding among pathologists.18It has been estimated that long-haired cats are twice as likely as short-haired cats to have frequent elimination of hairballs.3 This is consistent with the findings of our study, as most cats were considered long- or medium-haired (84.1%). Interestingly, 66% of the short-haired cats in this study were diagnosed with alimentary lymphoma. These findings identify a higher incidence of obstruc-tions in long-haired cats, which may suggest that cats with trichobezoars and short hair are more likely to have underlying gastrointestinal disease as a predisposing fac-tor. However, the small study population hinders our ability to draw definitive conclusions, warranting further studies.This study’s retrospective design introduces inherent limitations. The subjective nature of biopsy interpretation and lack of blinding among pathologists to the age, clini -cal signs and additional histopathology results within the same cat may cause considerable bias affecting the inter -pretation of samples. In addition, there is a lack of consist-ency among both biopsy quantity and specific location of biopsies, making accurate comparison difficult. Owing to the lack of follow-up in this study, there is no comparison between histopathologic diagnosis and response to treat -ment, thus preventing a definitive diagnosis of specific forms of FCE.ConclusionsOur findings suggest that the presence of a trichobezoar may alter the degree and/or type of inflammation pre-sent at the level of the obstruction, potentially limiting the ability to interpret biopsies from this site. Furthermore, histopathology changes are commonly found both orad and aborad to the obstruction, emphasizing the need to biopsy multiple sites of the small intestine. Interpretation of these findings should always be performed with regard to the individual’s chronicity of clinical signs and response to therapy. A prospective study with a stand -ardized number of biopsies and biopsy technique, with subsequent evaluation by blinded pathologists, is war -ranted to further characterize the findings of our study in an effort to develop clinical recommendations moving forward.Acknowledgements We would like to thank Dr Deborah Keys for her expertise in running our statistical analysis.

Answer 77

In this cohort, dogs with massive primary AGA -SACA that underwent anal sacculectomy overall had good outcomes with an acceptable incidence of ma -jor complications and relatively prolonged PFI and OS. However, consistent with prior reports demon -strating a greater incidence of metastatic disease with larger primary tumors, nodal metastasis was common in this population and the majority of dogs (64.3%) had stage 3 disease at the time of surgery. In addition, the majority (53.6%) of dogs in this cohort were hypercalcemic preoperatively. Therefore, mul -tiple previously reported negative prognostic indica -tors were present in this study population, though overall outcomes were relatively good.Intraoperative complications (all grade 2) asso -ciated with the anal sacculectomy procedure were reported in 14.3% dogs, and 1 (3.6%) additional dog experienced a grade 2 complication associated with lymph node extirpation. Importantly, rectal wall per -foration occurred in only 3 (10.7%) cases, whereas CT revealed possible rectal wall invasion in 15 (53.6%) dogs. This finding suggests that although many dogs with massive AGASACA may have concern for pos -sible rectal wall invasion based on CT, true determi -nation of rectal wall invasion and any intervention required is based on surgical findings. Digital rec -tal examination findings should also be considered relative to risk for rectal wall invasion, as mobility of the rectal wall over the anal sac tumor generally implies a lack of gross invasion of the rectal wall and unlikely indication for rectal wall excision and repair. (However, these data were generally lacking in many physical examination reports and were unable to be assessed in the current retrospective study.) Impor -tantly, rectal perforation/resection appears to be required in only a small proportion of cases with mas -sive AGASACA, despite features concerning for rectal invasion on CT in a majority of cases. However, of the 3 dogs that had surgical perforation of the rectum requiring repair, all developed postoperative com -plications including 3 grade 1 complications and 1 grade 3 complication (in a dog that also experienced a grade 1 complication). The grade 3 complication was directly related to the rectal repair, as this dog developed dehiscence and a rectocutaneous fistula. The only other reported intraoperative complication during anal sacculectomy was hemorrhage requir -ing intervention, which highlights the importance of being prepared to manage significant hemorrhage given the potential for extensive neovasculariza -tion of these tumors and close association with large vessels such as the caudal rectal branch of the in -ternal pudendal. One additional patient experienced hemorrhage requiring intervention during iliosacral lymphadenectomy, a procedure which reportedly has been associated with a relatively higher risk of hemorrhage. A recent study on 136 dogs that un -derwent metastatic iliosacral lymph node extirpa -tion reported an overall complication rate of 26% and hemorrhage in 18% of cases (with nearly half of these dogs requiring a blood transfusion), emphasizing the important consideration of the risk for hemorrhage in iliosacral lymphadenectomy.15 Overall, the inci -dence of intraoperative complications was relatively low and no grade 3 or 4 intraoperative complica -tions occurred despite the massive nature of these tumors, their robust vascular supply, and proximity to important surrounding structures. It is important to consider, however, that these have the potential to be challenging procedures, and the results of this study were obtained in a setting of 2 academic ter -tiary referral centers with surgeries performed by board-certified surgeons and surgical residents.Postoperative complications were reported in 10 (35.7%) dogs overall, including during hospitaliza -tion for 5 dogs (4 grade 1 and 1 grade 4) and af -ter discharge within 30 days of surgery for 7 dogs (4 grade 1, 2 grade 2, and 1 grade 3). The majority of postoperative complications reported were grade 1, and many of these would have been classified as sequelae, or generally anticipated and self-limiting outcomes of these procedures, in the recent Sterman et al study.10 In addition, the grade 4 complication that occurred during hospitalization (acute respira -tory distress syndrome and subsequent death) was unlikely to be associated with the surgical proce -dure itself and was considered more likely related to postanesthetic complications or systemic disease. Of the postdischarge complications, one of the grade 2 complications (urinary tract infection) was likely un -related to the surgical procedure itself. Therefore, only 2 postoperative complications above grade 1 were definitively attributed to the surgical proce -dure: 1 grade 2 postoperative complication (super -ficial surgical site infection) and 1 grade 3 postop -erative complication (deep surgical site infection and rectocutaneous fistula). The overall incidence of dogs that experienced postoperative complica -tions was relatively low, and the incidence of dogs that experienced grade 2+ postoperative complica -tions overtly associated with the surgical procedure (both characterized as surgical site infections) was only 7.1%. Therefore, there appears to be a low risk of major postoperative complications associated with anal sacculectomy in dogs with massive primary AGASACA, though surgical site infection is possible.Importantly, no dogs were reported to have long-term fecal incontinence, tenesmus, or anal stenosis/stric -ture postoperatively. Given the massive nature of the pri -mary tumor, nearly 50% circumference of anal sphincter may have been surgically traumatized for many of these dogs. The finding that no dogs developed permanent Unauthenticated | Downloaded 10/08/23 06:32 AM UTC 7fecal incontinence supports the general statement that permanent fecal incontinence is exceedingly rare follow -ing unilateral anal sacculectomy, even in the presence of massive AGASACA and substantial dissection of the ex -ternal anal sphincter. It has been reported that trauma to > 50% of the external anal sphincter or bilateral iatrogenic damage to the caudal rectal nerves can result in fecal in -continence; therefore, unilateral surgery should not result in permanent incontinence, unless underlying disease of the contralateral side exists.10 In addition, transient fecal incontinence was reported in only 4 (14.3%) dogs post -operatively, including prior to discharge in 2 dogs and fol -lowing discharge up to 30 days postoperatively in 2 dogs. Therefore, although fecal incontinence risk should be dis -cussed with owners, findings of this study suggest that permanent incontinence following anal sacculectomy is rare. The overall incidence of major intra- and post-op -erative complications associated with anal sacculectomy for massive primary AGASACA in dogs appears to be low and not substantially different from that reported for smaller tumors.10In considering local disease recurrence follow -ing anal sacculectomy, the reported recurrence rate in this cohort of dogs with massive AGASACA was relatively high (37.0%). However, this is within the range of recurrence rates reported previously (12% to 45%).4,10,13,16 The only risk factor that has been pre -viously associated with local recurrence is the pres -ence of lymphovascular invasion, and histologically incomplete or narrow excision of the anal sac tumor has not been associated with local disease recurrence to date.10 Due to inconsistent reporting of variables on histology reports in this cohort, histologic findings such as lymphovascular invasion or completeness of excision were unable to be assessed in association with recurrence. Regardless, this study demonstrated a relatively high rate of local disease recurrence fol -lowing anal sacculectomy for massive AGASACA, though good outcomes still occurred. The median time to documented local recurrence was 319 days for these dogs, demonstrating generally slow local dis -ease progression and prolonged time to recurrence.With regard to outcomes, these dogs with mas -sive AGASACA overall had prolonged PFI and OS. However, disease stage was significantly associated with PFI, and dogs with suspected nodal metastasis at the time of surgery had a 12.6 times greater haz -ard of disease progression compared to dogs with -out definitive nodal metastasis at the time of surgery. This is consistent with clinical impressions and prior literature, in which dogs with nodal metastasis at the time of surgery are anticipated to develop progres -sive metastatic disease postoperatively. In addition, the findings of this study support the notion that metastatic disease progression occurs through the iliosacral lymph nodes prior to distant metastasis, as potential distant metastasis was only documented in dogs with concurrent/prior nodal metastasis. How -ever, the OS of dogs in this study was relatively long (671 days), and disease stage was not significantly associated with OS in this cohort. One possible expla -nation for this is the inclusion criteria of the study in which all dogs underwent surgery, and 17 of 18 dogs with suspicion for metastatic lymph nodes preop -eratively underwent concurrent extirpation of their metastatic locoregional lymph nodes. Prior studies have demonstrated enhanced outcomes and survival times with extirpation of metastatic lymph nodes in dogs with AGASACA.1,5,11–13 Therefore, although the majority (64.3%) of dogs in this cohort had stage 3 disease at the time of surgery, their survival times were similar to or improved relative to prior studies on dogs with similar disease stage. For instance, Pol -ton and Brearley reported that in dogs with stage 3 disease, the median survival times ranged from 294 to 492 days for dogs treated via a variety of modali -ties.1 The present study highlights the potential for prolonged survival times in dogs undergoing anal sacculectomy for massive AGASACA despite a high incidence of metastatic disease at presentation, and concurrent lymph node extirpation may play an important role.In addition, adjuvant therapy was not found to be associated with PFI or OS in these dogs. Despite the multitude of negative prognostic indicators of dogs in this study (large primary tumor size, high incidence of metastatic disease, and high incidence of hyper -calcemia), adjuvant chemotherapy was not found to be associated with improved outcomes. This is con -sistent with prior studies, which have generally not demonstrated a definitive benefit of chemotherapy in dogs with AGASACA. However, although 16 dogs of this study received adjuvant chemotherapy, the protocols were highly variable and the rationale for adjuvant chemotherapy administration or protocol prescribed was not well characterized. Therefore, al -though this study does not support a role for adjuvant chemotherapy postoperatively in dogs with massive AGASACA, controlled prospective trials with specific protocols and inclusion criteria are required to further assess a potential role of chemotherapy. Similarly, de -spite the relatively high incidence of local disease re -currence postoperatively, adjuvant radiation therapy was not found to improve outcomes in these dogs, though prospective clinical trials are needed.This study had several limitations. First, due to the retrospective nature, complete clinical information was lacking for some patients and several patients were lost to follow-up. In addition, although all dogs had staging with abdominal/perianal CT preoperatively, postopera -tive staging was variable. However, the requirement of CT preoperatively is considered to be a strength of the study, as CT has been demonstrated to be more accurate in identifying abnormal-appearing lymph nodes com -pared to ultrasonography, and CT is considered the gold standard for primary tumor size measurement with po -tential for variability in reported measurements on rectal examination and formalin-fixed tissues.8,17 In addition, variable adjuvant treatments were performed, result -ing in small subgroups of patients that received or did not receive these adjuvant treatments, such that there was relatively poor power to identify potential differ -ences between these groups. Finally, selection bias may have occurred because all cases were contributed by academic institutions and all owners elected advanced diagnostics and surgical treatment. All cases included Unauthenticated | Downloaded 10/08/23 06:32 AM UTC8 were deemed to be surgical, and no stage 4 dogs were included in this study. Based on the inclusion criteria, no comparisons can be made between dogs with massive AGASACA that underwent surgery for treatment and those that did not undergo surgery.Ultimately, although these dogs with massive primary AGASACA had multiple previously described poor prognostic indicators, prolonged survival was achieved despite a high incidence of metastatic disease progression and local recurrence. Lymph node metastasis at the time of surgery was a nega -tive prognostic indicator for PFI but not OS in these dogs. Incidence of intraoperative and postoperative complications were relatively similar to those previ -ously reported for anal sacculectomy of smaller tu -mors. Therefore, on the basis of results of this study, surgery (including anal sacculectomy and possible lymph node extirpation for dogs with stage 3 dis -ease) should be considered a mainstay treatment in dogs with massive primary AGASACA amenable to surgical excision.AcknowledgmentsThe authors received no grant funding in association with the cases described in this report. The authors have nothing to declare.

Answer 78

In this study, it was important that the signalment resembledthe real-life situation as much as possible. To do so, cadaverswere sampled deliberately from various weight categories,and appeared to have a widely ranging LI maxand age, andwere allowed to have osteoarthritis. Based on the signal-ment, this was successful, as nearly the entire age, LI, andbody weight range were sampled.Theﬁrst goal of this study was to identify the relationbetween force applied during stress radiography and the LI(both LImaxand LI%) of this joint in intact cadavers of dogs.Before an in-depth analysis of the shape of the curve, thepotential in ﬂuence of several variables on the LI maxwasassessed because that is what is generally reported. Ideallythe LI maxwould be robust under variable circumstances. Thisdoes seem to be the case as force, position of the device, thepresence of osteoarthritis, side, or body weight did not seemto inﬂuence the LImax. The observation that the force at whichLImaxwas reached did not in ﬂuence the LI maximplies that theforce that must be applied to reach adequate subluxation ofthe hip joint does not depend on the laxity present in thatspeci ﬁc hip joint, which is a good characteristic. Further-more, the coef ﬁcients, which are depicting the observeddifferences in LI maxdirectly, of all these variables were alsovery small, and at most equal to the reference repeatabilityvalues reported when measuring the LI.9This also substan-tiates the ﬁnding that they are not signi ﬁcant not onlystatistically but also clinically. Either way, their effect wouldhave been too small to be relevant. While this is in agreementwith expectations for most factors, the absence of an associ-ation with osteoarthritis is interesting. The expression ofCollagen Type VIII Alpha 1 Chain (COL8A1) is signi ﬁcantlyincreased in the capsule and ligaments of coxofemoral jointswith canine hip dysplasia, resulting in ﬁbrosis of its cap-sule.13The hypothesis was that capsular ﬁbrosis mightdecrease the laxity of the coxofemoral joint.14A study byGold and colleagues showed an increased laxity on thestandard hip extended ventrodorsal projection and a similaramount of laxity on the stress radiograph before and afterdevelopment of osteoarthritis.15While this was not the goalof the present study, a longitudinal study to determine theinﬂuence of osteoarthritis would be interesting.Earlier studies have tried to evaluate the shape of theforce –laxity curve. Studies from 1993 and 1997 mounted thecadaver of a dog from which all muscles had been removed toa hydraulic machine that performed cyclic compression anddistention. These studies observed a sigmoid force –laxityrelation.16,17No lateral displacement, up until a certain forcethreshold was exceeded (phase 1), after which a steepincrease of the laxity was seen (phase 2), followed ﬁnallyby a plateau after any further increase in force did not resultin a further increase in laxity (phase 3). These studies hadtwo major differences relative to this study. First, the above-mentioned studies used cadavers without musculature. Theabsence of muscles allows evaluation of the joint capsulealone on laxity; in vivo the situation is more complex and isthe resultant from all the surrounding tissues. The presentFig. 3 Force –LI% curves comparing ( A) the right and left side, ( B) male and female cadavers, ( C) osteoarthritis and no osteoarthritis, and ( D)t h e ﬁveconsecutive sessions of three cadaver dogs. No signi ﬁcant associations were present between sides ( A), genders ( B), and osteoarthritis ( C)on the one hand and the LI% or LI maxon the other hand. In part ( D), the LI maxbetween sessions was reached at similar forces, the curves are similarlyshaped with a comparable course. Thus, these force –laxity curves are repeatable. All lines are LOESS-based regression curves (span ¼0.4; formula:LI%/C24force, dataset split according to the variable tested). OA, osteoarthritis; LOESS or LOWESS, Locally Weighted Scatter-plot Smoother..study probably resembles the real-life situation more accu-rately. The second difference relates to differences in theprocedure. The former studies were performed with PennHIPin mind. Whereas PennHIP requires three projections, theVMBDD technique does not require the compression view toobtain adequate laxity measurements.8Although it is as suchessential to evaluate the compression part of the graph whenperforming PennHIP, the compression part is irrelevant here.Thus, it is normal that phase 1 is not visible in the graphs(see►Fig. 2 ). The steep increase in laxity, phase 2, andespecially the plateau phase, which is phase 3 and themost relevant, is however present and the graphs closelyresemble the older studies.When the shape of the curve was assessed, the majority ofthe variables did not in ﬂuence the association, aside from themeasured force. A notable exception was the DH-VMBDmD /DCFJ-VMBDmD ratio that had a signi ﬁcant in ﬂuence on thecourse of the force –LI% curve, but not on the LI max.T h i sD H-VMBDmD /DCFJ-VMBDmD ratio re ﬂects the position of theVMBDmD along the proximodistal length of the femur andtherefore the length of the lever. It is logical that the length ofthe lever in ﬂuences when maximal laxity is reached; how-ever, it is ideal that it does not alter the LImaxitself.The second goal was to determine the variability of theLImaxand of the force –laxity curve. Although determiningthis is important from a technical point of view, it wasevaluated because some breeders believe that stress radio-graphs can induce canine hip dysplasia by permanentlystretching and damaging the ligaments and capsule of thehip joint (Broeckx B, personal communication). The LImax,t h eforce needed to achieve the LI max, and the curves remainedthe same over the various sessions. This substantiates thatthe displacement during stress radiographs is elastic and notplastic within our force ranges, or that the plastic deforma-tion happens during the ﬁrst cycle.18The latter is purelytheoretical and much less likely as there is no biologicalreason why these tissues would deform only during the ﬁrststress cycle. Thus, within these force ranges, this procedureseems to be safe and does not worsen or induce laxity of thehip joints. This is also what was expected as, for example, theground reaction forces when a medium-sized dog jumpsexceed our proposed suf ﬁcient force of 95.32 N by approxi-mately three times (1.7 body weight /C220 kg/C29.81 N/kg).19While the direction of the force vector of the ground reactionforces during jumping and the vector of the force duringlateral stress radiography cannot be directly compared, thecomparison offers a context to the abstract number of95.32 N. Additionally to the authors ’knowledge, there hasbeen no report of lameness after lateral stress radiography,which would be expected in case of plastic deformation.Elastic deformation was also found in an earlier study bySmith and colleagues.16The variability of the LI maxwas alsoin accordance with what we previously observed and wellwithin the published standards.9While this is an excellentquality check to evaluate the procedures in the current study,the study here adds additional information in what can beexpected in terms of variability along the curve whenperforming the procedure. As this is the ﬁrst study evaluatingthis variability along the curve, a comparison is not possible.However, a 9% LI standard deviation does correspond withsimilar values as the ones reported earlier (and deemed to besufﬁciently good) at the LImax.9Our third goal was to measure and calculate the forcenecessary to cause adequate subluxation of the hip joint. Theforce at which 90% of the hips reach at least 90% of their LI maxwas 95.32 N. This corresponds to a force of 9.7 kg, which isexpected to be feasible for every person performing theprocedure, especially because the VMBDmD functions as alever and thus the force exerted by the examiner can belower. This substantiates the clinical observation that theVMBDD was a method with a good technical repeatabilityand reproducibility to evaluate the hip joints when used bytrained clinicians.9It might be considered a limitation of this study that allradiographs and measurements were performed by the sameexaminer. The bene ﬁt of choosing an experienced person isthat the signal-to-noise ratio remains high. Further valida-tion studies are, however, needed to con ﬁrm the currentresults in patients. Anesthetic protocols may need optimiza-tion and standardization as these have been shown to in ﬂu-ence the FCI score and stress radiography results.6,20,21Furthermore, it would be interesting to study the positioningof the VMBDmD, as the ratio evaluating this turned out to besigniﬁcant.ConclusionThis research estimates the effect of various variables on theprocedure needed to quantify laxity with the VMBDmD. TheLImaxand the curve to reach the LI maxare not in ﬂuenced bydegenerative changes, body weight, gender, or age. While theposition of the VMBDmD (D H-VMBDmD /DVMBDmD-CFJ ratio)does not in ﬂuence the LI max,i tc a ni n ﬂuence how fast theLImaxis reached. As expected, there is a marked relationbetween force and LI%, and a force of 95.32 N seems to be thethreshold to reach suf ﬁcient laxity for 90% of the population.This level of force should be realistically achievable for everyexaminer. Furthermore, there is no evidence suggesting anypermanent damage (plastic deformity) in the coxofemoraljoint when performing the procedure: the force –laxity curveand the LImax between sessions are repeatable. Furtherstudies are necessary before extrapolating these ﬁndingsto patients and to further enlighten the biomechanics ofthese fulcrum-based stress radiographs.

Answer 79

This study demonstrates that CFRT is beneficial for gross and microscopic infiltrative lipomas, with a median OS of 4.8 years. To the authors’ knowledge, Figure 2 —Kaplan-Meier survival curve. The estimated median overall survival (OS) from completing radio -therapy was 4.8 years (1,760 days; 95% CI, 1,215 to 2,777 days; range, 23 to 3,499 days) for any cause of death, for gross and microscopic infiltrative lipomas combined. Censoring is indicated by a hash mark. The asterisk denotes that 2 dogs censored at 62 and 63 days are represented at this hash mark.Figure 3 —Kaplan-Meier survival curves. A—The es -timated median overall survival (OS) from complet -ing radiotherapy to death was not statistically sig -nificantly different for dogs with gross vs microscopic disease (gross median OS, 4.8 years [1,760 days] vs microscopic median OS, 3.6 years [1,322 days]; P = .45). B—The survival difference between females (median OS, 7.6 years [2,779 days]; 95% CI, 963 days to not reached) vs males (median OS, 4.6 years [1,665 days]; 95% CI, 335 to 2,245 days) approached statistical significance ( P = .05).Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 11/03/23 06:54 AM UTC 7this is the largest group of dogs and longest survival reported for infiltrative lipomas. The EQD2 values (Table 2) for the protocols used are largely similar, which limits our conclusions regarding optimal frac -tionation. Tumor control and survival with markedly different techniques (eg, hypofractionated or stereo -tactic) is yet undefined, along with long-term risks of hypofractionated protocols for dogs living many years post-treatment.As noted in previous studies,11 dogs were young to middle-age, and generally larger breeds. Distant metastasis was not reported, and the dogs that de -veloped metastatic cancer later in life had newly diagnosed cancers with known metastatic risk. The only dog with suspected new cancer in the irradi -ated region developed disseminated lung nodules; it is unclear if this was related to the CFRT site, from a primary lung cancer, or from another distant cancer. Although radiographically diagnosed pneu -monia was reported for 2 patients, it was not clear whether persistent radiation-induced pneumonitis/fibrosis contributed to the imaging vs solely pneu -monia. Staging diagnostics were unremarkable for most, but the 14.2-year-old dog euthanized with a hemoabdomen and adrenal mass within weeks of CFRT highlights the importance of assessing for con -current disease in older dogs.In this study, no survival difference was found for the assessed factors except for the near significance of sex. Importantly, although 3 dogs were lost to fol -low-up, death attributed to an infiltrative lipoma was not reported, and only 1 dog was confirmed to have recurrence 923 days post-treatment, demonstrat -ing that many of these dogs died with their lipoma rather than because of it. Similarly, the impact of sex on survival is likely influenced by factors beyond the lipoma or radiotherapy, and age at death must be in -terpreted with caution as to whether lifespan itself may have resulted in females having different surviv -als.24 A prospective evaluation of time to progression would define prognostic variables for recurrence but was not possible in this retrospective study.Consistent with previously reported cases,11 and in contrast to many other tumor types, gross disease did not result in shorter survivals. Therefore, this in -stitution offers radiotherapy for gross and recurrent infiltrative lipomas. All dogs in this study had at least 1 surgical debulking in the years prior to radiotherapy, so it is difficult to conclude whether primary irradia -tion of infiltrative lipomas (without surgery) provides the same outcome. However, based on previously published cases11 and our study, a prospective analy -sis of dogs treated with conventionally fractionated radiotherapy without surgery would be extremely helpful to practitioners debating surgery for this dis -ease. Additionally, based on the outcomes with gross disease, dogs receiving 1 surgery that results in in -complete resection or recurrence may benefit from pursuing radiotherapy instead of repeated surgeries.There were several dogs with extensive recur -rence after surgery alone, several with gross tumors that could not be resected without significant morbid -ity, and a number of dogs with minimal gross disease post-surgery. Because of the variability in tumor-bur -den in the 16 gross-disease dogs, and difficulty cal -culating accurate gross tumor volumes due to uncer -tainty of what strands of fat are normal versus tumor on CT in some cases, assessing outcomes based on numerical gross tumor volume was not feasible.CFRT can help avoid late effects in normal tis -sues.25 The spinal cord doses were within accept -able limits at this institution for CFRT, and did not exceed 2.6 Gy/fraction (constraint, < 3 Gy/fraction), and also maintained maximum cord dose < 50 to 60 Gy.25,26 Based on limited follow-up data, no patients were reported to have spinal changes consistent with late-radiation myelopathy on physical exam or imaging. Tracheal doses did not exceed 3.2 Gy/fraction in the 8 dogs with data available (Table 3). Although this institution now attempts to keep V20 for both lungs < 37% to minimize pneumonitis,27 not all cases in this study were contoured with both lung lobes, and the ipsilateral lung was allowed to receive focally higher doses. Focal pneumonitis was noted in 3 dogs without clinical signs. Specific constraints for other OARs were not in place for most dogs, but OAR doses were minimized as much as reasonably achievable. In recent years, OARs have been given an added error volume for motion and position un -certainty (PRV) that were not employed at the time of these cases.There are limitations to this study. Although this group is the largest to date, it is still from a single institution and may have institutional/regional bi -ases. Varied and evolving treatment techniques uti -lized over many years also limit evaluation of field and PTV parameters. Stable disease could be related to radiotherapy, or to slow progression. Finally, lack of statistical differences between groups could be from low power or type II error. In conclusion post-operative radiotherapy is associated with lengthy survivals for infiltrative lipomas. Further assessment of necessity for surgery prior to CFRT, time-dose-fractionation, prospective monitoring of tumor re -sponse, acute and late effects, and follow-up with 3-D imaging, would be helpful to determine optimal radiotherapy options.AcknowledgmentsNone reported.DisclosuresThe authors have nothing to disclose. No AI-assisted technologies were used in the generation of this manuscript.FundingThe authors have nothing to disclose.

Answer 80

In the present study, 24/24 (100%) sti ﬂes with cranial cruci-ate ligament rupture and concurrent MPL treated with TPLO-TTT had no functional de ﬁcit detected during owner andsurgeon assessment at last follow-up ( >1 year after surgery).The major complication rate was relatively low at only 4/24stiﬂes after following up with patients for a minimum of1 year. In our patient population, body weight ranged from3.2 to 43 kg, suggesting that the technique described may beapplied in dogs of different sizes.The short-term outcome reported by Leonard and col-leagues4w a sb e l i e v e dt ob eo fs u f ﬁcient duration to accesssuccessful bone healing and implant stability (once the bone ishealed, implant migration is very rare), but this time frame wasnot suf ﬁcient to preclude patellar re-luxation and developmentof delayed complications such as implant irritation (from theKirschner wires and/or cerclage wires), and long-term surgicalsite infection. Our study reported a similar high success rate andlonger follow-up. We tried to alleviate differences in treatmentprocedures as much as possible by including only dogs withcranial cruciate ligament rupture and concurrent grade III or IVMPL that were treated by the same orthopaedic surgeon withstandardized additional procedures (trochlear wedge recession,medial retinacular release, and lateral capsular imbrication) inaddition to the TPLO-TTT surgery.Surgical site infections can be observed independentlywith TPLO as well as the various surgical techniques foraddressing an MPL.1Our surgical site infection rate wassimilar to that observed with TPLO alone, ranging from 3to 15.8%.15The other major complication encountered in ourstudy consisted of a recurrent grade II MPL. In this case, thegrade II reluxation implies that something else needed to beaddressed since a reluxation occurred. In this dog, surgicalcorrection of medialization of the tibial tuberosity associatedwith an internal tibial torsion and cranial cruciate ligamentrupture might have been addressed using a modi ﬁed TPLOwhere the distal tibial segment was externally rotated (inrelation to the osteotomized tibial plateau fragment) andlaterally translated, as described previously.5We do notbelieve this grade II patellar reluxation was a limitation ofthe TPLO-TTT technique, but rather an inadequate caseselection or decision-making. The TPLO-TTT technique isnot applicable to every case of patellar luxation, but onlycases that have cranial cruciate ligament insuf ﬁciency andmedialization of the tibial tuberosity with no femoral ortibial torsion.4Interestingly, none of the 10 dogs weighingmore than 20 kg in our study developed major complicationsin the long-term follow-up. Our results compared favorablywith some previous studies reporting up to 10% majorcomplication rate (patellar re-luxation, implant failure) forMPL surgery in large-breed dogs.16,17Patellar ligament thickening was the most frequentlyencountered complication in 8/15 sti ﬂes at the time of the8- to 10-week in-hospital evaluation in a previous study.4Incontrast to our results, only one of these eight sti ﬂes devel-oped clinical signs of discomfort. Whether this patellarthickening was due to the surgical trauma (trauma by thesaw blade, placement the pins through the distal patellarligament), early excessive activity, a change in sti ﬂeb i o m e -chanics, or a combination of these remains unknown. Similarﬁndings have been previously described with TPLO or TTTwhen performed alone.17,18Tibial plateau leveling osteotomy and concomitant TTThave been described as a predisposing factor to tibial tuber-osity fractures, implant migration, and delayed or compli-cated bone healing.7,19 –22Similar to Leon ard and colleagues ’study,4we did not observe any tibial tuberosity fracture inour case series and all sti ﬂes exhibited clinical union at short-term follow-up with no implant migration at the last follow-up examination. We do believe that an adequate width of thetibial tuberosity segment remains one of the key issues whenperforming the TPLO-TTT to lower the likelihood of tibialtuberosity fracture and allow the placement of robust andsecure ﬁxation.19One limitation of the present study is the small number ofcases that prevents determination of outcomes representa-tive of a larger population with cranial cruciate ligamentrupture and concurrent MPL. Retrospective design precludesstandardization of the surgical technique, postoperativetreatment, and follow-up. We tried to control for certainvariables by only including dogs with cranial cruciate liga-ment rupture and grade III or IV MPL that were operated onand seen on reexamination by the same experienced ortho-paedic surgeon. We also excluded dogs treated that hadfemoral or tibial osteotomy or ostectomy for correctingfemoral or tibial torsion, respectively. Long-term prospectivestudies that utilize force plate analysis for objective gateassessment are advised.In conclusion, cranial cruciate ligament rupture and con-current MPL (associated with medialization of the tibialtuberosity) may be managed in dogs using a single-stageTPLO-TTT procedure in combination with additional proce-dures such as trochleoplasty and soft-tissue (retinacular)release or imbrication.

Answer 81

Shoulder arthroscopy is considered the “gold standard ”forevaluation of the stabilizing structures of the shoulder.2–4,6Although preoperative assessment with magnetic resonanceimaging (MRI) has been proven to be a helpful adjunctivediagnostic technique with relatively strong agreement andconcordance to arthroscopic ﬁndings in the biceps tendonand medial glenohumeral ligament, de ﬁnitive diagnosiscontinues to rely on intraoperative evaluation.3,7,8Usingan ink injection technique to quantify the arthroscopic ﬁeldof view with a standard lateral portal, this study determinedthat only 48% of the biceps brachii tendon was visible Thisincreased to 63% once the shoulder was placed in ﬂexion.Fifty-eight percent of the medial glenohumeral ligament wasidenti ﬁed to be directly in the ﬁeld of view, while just 20% ofthe subscapularis tendon was directly in the ﬁeld of view.Understanding the extent of the arthroscopic visual ﬁeld isrelevant when considering injuries to and therapy for intra-articular structures.Minimally invasive or arthroscopic-assisted orthopaedicprocedures have been proven to reduce postoperative dis-comfort both in humans and in canine patients, and as suchsurgical treatment continues to focus on the development ofless invasive techniques.9Medial shoulder instability, acommon cause for forelimb lameness in dogs, is often local-ized to pathology in the medial glenohumeral ligament.10–12In this study, the extent of direct observation was 58% of thecranial arm of the ligament. This clinically correlates to themost central portion of this structure. Assessment ofthe origin and insertion points would most likely requirefurther limb manipulation (abduction) along with probing ofthe structure to access integrity. Rupture of the tendon oforigin of the biceps brachii is the second most commontendon injury in dogs, and should be readily visible withintypical arthroscopic ﬁeld of view.13,14Other pathologies ofthe biceps tendon, namely, biceps tendinopathy, have provenamenable to arthroscopic treatment.15–17However, withover 30% of the distal aspect of the tendon not observed,injuries in this region and at the musculotendinous junctionare likely to be missed. Injuries to the muscle/tendon junc-tion or muscle body of the biceps and subscapularis havebeen documented but would not be identi ﬁed on arthro-scopic view.13Further evaluation with ultrasound and/orMRI would likely be required in these cases.8The lateral approach to the shoulder joint with the patientin lateral recumbency is considered the “standard ”ap-proach.17,18Other arthroscopic approaches to the canineshoulder have been described. A cranial port is typicallyused for procedures that involve the biceps brachii mus-cle.15,19A medial approach has been used primarily forFig. 6 Percentage of the intra-articular biceps tendon length within the arthroscopic ﬁeld of view at a 115-degree standing angle and at a 75-degree ﬂexed angle. This difference in percentage of length is signi ﬁcant ( p¼0.0003)..evaluation of the lateral stabilizing structures.19The lateralapproach used in this study has been shown to provide themost reliable, easily accessible, and widest ﬁeld of view of thejoint as a whole relative to other described methods.19,20Forthis reason, alternative approaches to the canine shoulderwere not evaluated for comparison. Future studies may bepursued to compare the standard lateral approach withalternative scope portals and patient positioning.There are several limitations to this study. As a cadavericstudy, the full effect of the freeze/thaw cycle on jointdistension could not be fully accounted for. In an attemptto control for possible tissue stretching, all tissues werehandled similarly and the data have been presented aspercentages as opposed to absolute measurement. In addi-tion, joint expansion may have been affected by the use of agravity ﬂow saline infusion system as opposed to anarthroscopy-speci ﬁc infusion pump. The gravity ﬂow sys-tem was chosen as the authors commonly used this in theclinical setting. There may be a potential for increased jointexpansion with living tissues and high saline infusionpressure settings. The study design evaluated the differ-ences in visual ﬁeld in the standing joint position and jointﬂexion, but improvement or reduction in visibility withabduction or adduction was not evaluated. Further studiesare required to quantify the degrees of adduction andabduction and their impacts on the arthroscopic ﬁeld.Finally, this study only examines the tissues within thedirect ﬁeld of view, while an important aspect of arthro-scopic shoulder inspection is assessing the integrity of thesupporting tissues through probing, which may revealinjuries outside the ﬁeld of view.Challenges arose with the marking techniques used in thisstudy. The marking technique of dye injection into themargin of tissue within the arthroscopic view proved effec-tive but not without technical limitations. While markingnumerous joint structures was initially attempted in avariety of positions, this approach led to challenges inidentifying numerous landmarks during dissection andwas rejected for a more targeted evaluation of the bicepsbrachii tendon, subscapularis tendon, and medial glenohum-eral ligament. With this revised approach, a maximum offour ink marks were deposited into each shoulder, and thedye markings were repeatably, appropriately distinct andmeasurable. These supporting structures were able to bedissected as a whole without disruption of the markings ortissue integrity.In this study, as in standard clinical arthroscopy, thesynovial re ﬂection of the caudal portion of the subscapularistendon was not consistently identi ﬁable, preventing a trueintra-articular measurement for this tendon.19Although thisstudy quanti ﬁes the measurable length of the visible tendon,these stabilizing structures are three-dimensional in natureand are able to be evaluated in more than one plane witharthroscopy. Linear measurement does not re ﬂect the extentof circumferential evaluation possible with the advancedarthroscopic technique.ConclusionThe results of this study con ﬁrm our hypothesis that theproportion of biceps tendon visible by arthroscopy would besigniﬁcantly greater with the shoulder positioned in ﬂexionas well as our clinical suspicion that less than 75% of each ofthree supporting structures examined routinely are withintheﬁeld of view during lateral shoulder arthroscopy. Al-though a global impression of joint pathology can be readilymade with standard shoulder arthroscopy, understandingthe limitations of this view should be considered whenevaluating the biceps tendon, medial glenohumeral liga-ment, and subscapularis tendon. Future studies are neededto deﬁne maneuvers that would further improve visibility ofrelevant joint structures.

Answer 82

The laparoscopic extra-abdominal transfascial suturingtechnique for diaphragmatic circumferential rupturerepair was found to be a feasible, complication-free pro-cedure in this case, and was associated with low morbid-ity. A similar technique has been reported in humans totreat small defects where it is difficult to suture the her-nia orifice when the anterior rim is absent (Morgagni-Larrey's diaphragmatic hernia repair).14,15As far as theauthors are aware, this is the first case report in the veter-inary literature. Alternative, minimally invasive surgery(MIS) techniques described the use of intracorporealsuture material like unidirectional barbed suture (VLoc180 Covidien, Italia) or Endostitch (Covidien, Mansfield,Massachusetts, USA).8Another possible approach is theuse of staples (Endo Hernia Stapler; Covidien), designedfor hernia closure in patch repairs using mesh. However,intracorporeal suturing of wide defects is challengingeven for experienced laparoscopic surgeons.16–18Inhumans the laparoscopic extra-abdominal transfascialsuturing technique has been used to suture the posteriorrim of the hernia to the full thickness of the anteriorabdominal wall, eliminating the need for intracorporealFIGURE 4 Postoperative image. The green arrows indicate the3 laparoscopic ports, while red arrows show the extra-abdominaltransfascial sutures. Caudal (Cd), cranial (Cr).FIGURE 5 Recheck 3 weeks postoperatively. The red arrow indicates the skin irritation after suture removal (A). Dorso-ventral andmedio-lateral chest radiographs (B, C). Right (R), left (L).CINTI and RUBIO 867 1532950x, 2023, 6, suturing or mesh.14,15This method may be useful interms of ease of placement and security of sutures. Theapplication of the laparoscopic-assisted transfascialsutures could be performed with a different device suchas a port closure needle (Endo Close), epidural needle(Portex Epidural Minipack System), or with a standardneedle holder.14,19The suture pattern for diaphragmaticreconstruction can be in simple interrupted, simple mat-tress, continuous, or continuous locking patterns.6In thiscase a simple interrupted pattern was used; however, amattress suture pattern could also have been used for thistechnique, to increase the tension distribution across thewound in comparison with a simple interrupted pattern.6As reported in the literature, mattress sutures can be placedwith an extracorporeal or intracorporeal approach using astandard needle holder or laparoscopic needle holder,respectively.15,21Al a r g en e e d l ew a ss e l e c t e db yt h ea u t h o r sfor easier extra-abdominal application in this case. Nointraoperative complications r elated to needle manipulationwere recorded; however, careful needle manipulation underintra-abdominal visualization should be always performedto avoid thoracic or abdominal organ trauma.During conventional laparoscopic diaphragmatic rupturerepair, the insufflation pressure recommended for creatingoptimal working space will cause tension pneumothorax.Thus, intra-abdominal pressure should be decreased whencompared with other laparos copic surgeries in which thediaphragm is intact.8,20Maximum thoracic insufflation pres-sure should not exceed 5 mmHg. In healthy cats, a 3 mmHgintrathoracic pressure is associated with less acidosis, bettercardiac index, less cardiac oxygen consumption, and a simi-lar amount of working space than 5 mmHg.8,20In smalldogs and cats, hernia repair may be challenging due to thesmall working space. For these reasons, a recent studydescribed a new device used for abdominal traction in gas-less laparoscopic reconstruction of diaphragmatic hernias indog cadavers.21This new device for gasless laparoscopy(or lift laparoscopy) allows diaphragmatic herniorrhaphy byintracorporeal suture or mesh implantation and reducespneumoperitoneum-related changes.21Both suture andmesh graft techniques for exper imental diaphragmatic her-niorrhaphy can be performed using this new device in thispreclinical model, and this gasle ss device presents the poten-tial for further investigation in clinical cases.21Thus, due topotential complications related to carbon dioxide pneumo-peritoneum, gasless surgery (or lift laparoscopy) is a promis-ing alternative for diaphragmatic hernia repair in smallanimals.8,20,21Similarly, in the present ca se report, the first xiphoidsuture, placed through an extra- abdominal transfascial tech-nique, permitted lifting of the abdominal wall and dia-phragm, improving the visualization and working space,and avoiding increases in insu fflation pressure, therebyreducing the risk of excessive pneumoperitoneum-relatedchanges.Successful diaphragmatic rupture repair by MIS iseasier to complete in acute compared to chronic hernia-tion. This is due to the absence in acute trauma of fibroustissue on the edge of the hernia, adherence and strictureof hernia port and organ's compression.8,10,11It is notpossible to decide from any imaging modality which her-nia will be reducible or repairable with laparoscopy. It isnecessary to explore each case with laparoscopy to beable to make a decision on the possibility of MIS hernior-rhaphy.8,12Although the cats have a preponderance ofcircumferential tears (59%) and fewer radial tears (19%),the decision of which laparoscopic diaphragmatic repairtechnique is used depends not only on the type of dia-phragmatic tear (circumferential, radial, or combination),but also on the dimension of the diaphragmatic lesion,the clinical condition of the patient and the chronicity ofthe lesion.3,8,10 –12If the reduction or the repair is toochallenging or the clinical condition of the patientworsens, the laparoscopy will have to be converted to anopen approach. Another challenge of diaphragmatic rup-ture MIS treatment is the reduction of the herniatedorgans, especially the spleen and liver lobes, withoutinducing severe bleeding from the parenchyma.8,10–12However, this complication can be reduced with minimalblunt manipulation or with a dual –thoracoscopic andlaparoscopic –approach that may be advantageous fororgan reduction with simultaneous pushing from the tho-rax and traction from the abdominal cavity.8In this cat,the herniated organs were easily reduced with bluntmanipulation, gentle traction and help with the reverseTrendelenburg position, while the circumferential tearwas treated successfully with an extra-abdominal trans-fascial suturing technique with a low complication rate.The minor postoperative complication of skin irritationseen was thought to be associated with the extra-abdominal sutures. This resolved without any treatmentfollowing suture removal. However, to reduce the risk ofwound lesions, the sutures could be preplaced and sup-ported by plastic drain tubing, before closure, to preventsuture abrasion of the skin. Alternatively, after reductionof the hernia, a small skin incision could be performedbefore each suture application. A small skin incision per-mits burial of each suture and avoids inflammation inthe postoperative period, as reported for the laparoscopic-assisted inguinal herniorrhaphy technique.84|CONCLUSIONSThe laparoscopic extra-abdominal transfascial suturingtechnique for diaphragmatic circumferential rupture was868 CINTI and RUBIO 1532950x, 2023, 6, found to be a feasible, and effective technique in the cat.Further studies are required to understand better the pos-sible intraoperative and postoperative complications in alarge number of cases treated with this technique.ACKNOWLEDGMENTSAuthor Contributions: Cinti F, DVM, PhD,GPCert(SASTS), Dipl. ECVS, MRCVS: Performed thelong-term follow-up assessment of the cat; contributed toresearch, and wrote the case report. Rubio DG, DVM:Managed the clinical case presented, contributed to theresearch, and reviewed and edited the case report.The authors would like to thank Dr. Fabio Espositofor the illustration in Figure 1and Dr.ssa MariaMontenegro for the illustration in Figure 3.CONFLICT OF INTEREST STATEMENTThe authors declare no potential conflicts of interest withrespect to the research, authorship, and/or publication ofthis article.INFORMED CONSENTInformed consent (verbal or written) was obtained from theowner or legal custodian of all animals described in thiswork for the procedures undertaken. No animals or humansare identifiable within this publication, and therefore addi-tional informed consent for publication was not required.ORCIDFilippo Cinti https://orcid.org/0000-0003-1680-0523

Answer 83

The dog described in this case report was diagnosed withsmall intestinal strangulation secondary to EFE, whichhas not been described previously in veterinary literaturein dogs. In humans, pathogenesis of FWHs often fallsinto three categories: excessive visceral mobilitysecondary to anatomic or pathologic reasons, abnormalenlargement of the foramen, or changes in intra-abdominal pressure.8No underlying anatomic abnormal-ities were noted in the dog in this report, but chronicvomiting might have resulted in increased abdominalpressure and altered intestinal position and peristalsisthat could have encouraged herniation.Horse and human EFE/FWH commonly present withacute, severe abdominal pain if the bowel is obstructed;however, some humans have milder signs from nonob-structive hernias that are present for years.2,8,9Becausethe dog in this case report had not undergone abdominalimaging before onset of acute pain, it is unknownwhether the chronic digestive tract signs were from her-niation or another undiagnosed condition. However, res-olution of lifelong gastrointestinal signs after herniareduction could indicate the EFE had been presentchronically.In horses, diagnosis of EFE is suspected on ultrasoundwhen dilated, atonic loops of small intestine are identifiedin the area of the right flank.11In humans, the presence ofsmall intestinal loops along the lesser curvature of thestomach caudal to the liver is suggestive of FWH on com-puted tomography, the modality that is currently the goldstandard for preoperative diagnostic imaging.8Similarfindings were noted on ultrasound in the dog in thisreport. Treatment of the hernia is surgical reduction ofherniated viscera and resection of ischemic intestine.6–8Inhumans, reduction of hernial contents may require open-ing the lesser omentum to facilitate intestinal manipula-tion, incising the gastrohepatic ligament to enlarge theforamen, or decompressing or resecting affected bowel seg-ments first.8,9In the dog in this case report, the intestinewas easily reduced, and the strangulated segment wasresected after hernia reduction.In dogs, etiologies of gastric dysmotility can be pri-mary, such as ulcerative, infectious, inflammatory,obstructive, or neoplastic gastrointestinal conditions orabnormal myoelectrical activity, or secondary, such asstress, hypoperfusion, electrolyte abnormalities, meta-bolic disease, drugs, obesity, or sepsis.12–14In humans,gastroparesis can also occur with vagal nerve damageduring surgery.15In the dog in this report, gastroparesiswas likely multifactorial, including gastrointestinal ulcer-ation, opioid administration, peritoneal inflammation,visceral hypoperfusion, and thick gastric content. Caudaldisplacement of the stomach could also have damagedvagal nerves or decreased myoelectric activity.Treatment of gastric dysmotility includes prokineticdrugs, analgesia, fluid therapy, correction of electrolyteimbalances, early ambulation and enteral feeding, andtube decompression if medical management is ineffec-tive.14Nasogastric and GTs have been used for gastric1242 KERBY ET AL . 1532950x, 2023, 8, decompression in dogs, cats, and humans.16,17In the dogin this report, decompression with NGT was unsuccess-ful, and gastrotomy was performed to remove thick,semisolid contents. The GT was placed to keep the stom-ach decompressed after surgery and monitor GRV. Inhumans, measurement of GRV has been recommendedto reduce the risk of vomiting, reflux, and aspirationpneumonia and determine administration rate and vol-ume for tube feeding; however, it has not been proven toreduce the risks.18In critically ill dogs receiving enteralfeeding, GRV is not correlated with vomiting or regurgi-tation.12In the dog in this report, enteral feedings wereadministered via the NJT, while the GT was only used forremoval of GRV to facilitate resolution of gastricdysmotility.Reported dehiscence rates for dogs undergoing intes-tinal resection and anastomosis range from 9 to 16%;increased risk is noted with preoperative septic peritonitis(dehiscence rate 35 –38%) and preoperative hypoalbumi-nemia <2.5 g/dL (dehiscence rate 29%).19–23Covering theanastomotic site with a vascularized omental pedicle candecrease the risk of dehiscence by sealing the wound andimproving blood supply.20Leak testing is used to evaluate intraoperative anasto-motic integrity.20,24,25Intraoperative leak testing reducesthe postoperative risk of clinically significant leaks anddeath in humans; however, it may not reduce the risk ofpostoperative dehiscence in dogs.20,24,25The dog in thiscase developed septic peritonitis from anastomotic dehis-cence 3 days after jejunal resection, despite local omenta-lization and intraoperative leak testing. The role of theintestinal wall hematoma in its anastomotic dehiscence isunknown, but it may have been a contributing factor.Persistent hypoalbuminemia, ileus, and intestinal ulcera-tion likely played a role in dehiscence.Treatment for peritonitis includes correction of fluidand electrolyte abnormalities; administration of colloidsif the animal is hypoalbuminemic; initiation of broadspectrum antibiotic therapy, such as a beta lactam andfluoroquinolone, while cultures are pending; surgery tocorrect the underlying condition; abdominal drain place-ment if bacteria, fibrin, and debris cannot be lavagedfrom the abdomen; and nutritional supplementation.22The dog in this report was empirically treated withampicillin-sulbactam and enrofloxacin until finalized cul-ture results were deemed negative.Early enteral feeding is important for maintaininggastrointestinal integrity and treating hypoalbumine-mia.26Nutritional support was provided via the NJ tube.Feeding rates are usually based on clinician preference orexperience, with most feedings starting at a fraction ofresting energy requirements while the dog is monitoredfor signs of intolerance, such as nausea or diarrhea, thengradually increased in rate over several days.26Complications of EFE surgery in horses includeuncontrollable intraoperative hemorrhage, inability to per-form a complete resection, postoperative reflux unrespon-sive to treatment, systemic inflammatory responsesyndrome, peritonitis, laminitis, and anastomotic obstruc-tion.10In one study, survival to discharge was 48%, and30% of surviving horses subsequently had at least one colicepisode.10In humans, mortality rates for open surgeryrange from 36% to 49%; delays in diagnosis may increasemortality.8A recent review, however, reported survival ofall 15 people undergoing laparoscopic repair that includedone or more of the following procedures: bowel or gall-bladder decompression, bowel resection, cecopexy, or fora-men obliteration with sutures or omentum.8This case represents the first description of caninesmall intestinal herniation through the epiploic foramen.Although the dog developed septic peritonitis secondaryto anastomosis dehiscence, a second jejunal resection andanastomosis ultimately resulted in clinical improvementand resolution of signs.ACKNOWLEDGMENTSAuthor Contributions: Kerby MD, DVM: Correspondingauthor, study design, manuscript preparation, final prepa-ration of submitted manuscript. Tobias KM, DVM, MS,DACVS: Coauthor, primary surgeon on the case, criticalrevision of manuscript, final approval of submitted manu-script. Monto T, DVM: Coauthor, diagnostic imaging inter-pretation, figure image preparation. Morandi F, DVM, MS,DACVR, ECVDI, EBVS: Coauthor, diagnostic imaginginterpretation, figure image preparation.CONFLICT OF INTEREST STATEMENTThe authors declare no financial or other conflicts ofinterest.ORCIDKaren M. Tobias https://orcid.org/0000-0001-5261-8126

Answer 84

The results of this study partially reject the hypothesis thatacrylic ESF constructs are not affected by the position of thetransﬁxation pins in the columns. Eccentric pin positioningdecreased failure load of the ESF constructs under four-pointbending forces by 28%. However, pin positioning had no effecton stiffness and yield load under four-point bending and axialcompression, as well as failure load under axial compression.These results are in disagreement with a recent study byLeriquier and colleagues, which measured the stiffness andfailure load of isolated acrylic columns subjected to axialcompression, with trans ﬁxation pins placed in centric oreccentric position.6Indeed, they found no signi ﬁcant differ-ence in failure load between acrylic columns with centric oreccentric pins, and a signi ﬁcant decrease in stiffness of eccen-tric constructs. However, this study and the one by Leriquierand colleagues, both conclude in a weakening of constructswith eccentric pins, whether it concerns their stiffness, yield,or failure loads.In addition to the importance of pin centring, contouringof the acrylic columns has been shown to decrease theirstrength and rigidity.5,7In this context, although severalstudies have shown comparability, or superiority, of acrylicESF compared with metallic ones, these have been in modelswith straight column and centric pins.11,14 –16Yet, frequentclinical applications of acrylic ESF are in challenging situa-tions requiring contouring of the acrylic column to adapt tothe bone shape or placing pins close together and at differentangles when small fracture fragments are present, makingcentring of the pins dif ﬁcult to achieve.16,17The surgeonshould arrange the connecting columns to optimize thestrength of the pin-acrylic interface and to counteract theexpected forces on the fracture.Several other factors in ﬂuence the biomechanical proper-ties of acrylic ESF, including the number, position, type andsize of the trans ﬁxation pins.18,19The slippage of the trans-ﬁxation pins within the bone models during axial compres-sion highlights the importance of pin choice. The use ofsmooth pins in this study was motivated by their accessibili-ty, ease of use and lower cost. However, threaded pins aresuperior to smooth pins because they resist pull-out better,and therefore smooth pins should not be used clinically.20–22The strength of the pin-acrylic interface can be improved byincreasing the surface irregularity of the pins.1Modifying thesurface of the pins by making ﬁve notches in the shaft createsa pin-acrylic bond of similar strength to knurled pins, asshown in the study by Case and Egger.1This added strengthcould have prevented the slippage of the pins in the acryliccolumn observed in our study and potentially decreased therisk of catastrophic failures clinically. Another option toconsider that will counteract pin slippage is pin bendingwithin the acrylic column.19Slippage of the pins duringtesting resulted in non-standard load/displacement graphswith variations at the beginning of the curves. For thisreason, the linear portion of the curves before obvious plasticdeformation occurred was determined visually. Althoughefforts were made to keep consistency in the determinationof the linear portion of the curve, the method used is stillsubjective. The use of threaded pins would likely haveprovided more consistent graphs, and maybe standard meth-ods of calculation of the yield load could have been applied.Synthetic bone models of acetal homopolymer were usedin this study. The use of a synthetic material instead ofcadaveric bone was chosen to ensure repeatability duringtesting and minimize the variation in the size and mineralcontent of cadaveric bones as well as differences in age, sexand breed of animals from which bones are harvested. Thechoice of this material was motivated by its availability andTable 1 Mean/C6SD stiffness (N/mm), yield load (N) and failure load (N) during axial compression and four-point bending forconstructs with centric and eccentric con ﬁgurationsStiffnessN/mmYield loadNFailure loadNAxial compression Centric 87 /C625 301 /C659 525 /C660Eccentric 107 /C623 270 /C684 552 /C646Four-point bending Centric 166 /C616 751 /C6125 1,419 /C6185Eccentric 142 /C615 671 /C644 1,039 /C6162.its use in previous in vitro biomechanical studies.23,24Sincethe object of this study was the pin-acrylic interface, thebehaviour of the pin-bone interface was less relevant, andother materials such as epoxy composites or polyurethanecould also have been considered.25,26There are several limitations to this study. The in vitronature cannot reproduce the complexity of the environmentand combinations of forces exerted on a real fracture site.However, it does allow for standardization of stresses andconstructs, which is necessary for the development of gen-eralizable results that rationalize decision making in a clini-cal setting. Even though eccentric positioning of pinschanged some biomechanical properties of the constructs,it is important to highlight that all pins were eccentricallypositioned, and this is rarely seen in a clinical setting. Thesigniﬁcance of the results obtained in this study is uncertainin stiffer constructions such as type II or type III ESF.Determination of the effects of cyclic loading on the con-structs would also provide additional information relevant totheir clinical use. Despite these limitations, it is fair toconsider the potential bene ﬁt of correctly placing the trans-ﬁxation pins at the centre of the acrylic columns when theyare used in a clinical context.In conclusion, eccentric position of trans ﬁxation pinswithin the acrylic columns signi ﬁcantly decreases the failureload of type I acrylic ESF constructs subjected to bending.While acrylic offers several advantages, care should be takento maximize centring of the pins within the columns.NotesThis work was submitted in abstract form and acceptedfor oral presentation in the Resident ’s Forum at theAmerican College of Veterinary Surgeons (ACVS) SurgerySummit, Portland, United States, October 2022.

Answer 85

In support of our hypothesis, the use of combined trans-patellar and suprapatellar orthopedic TBW augmentationin addition to a primary core and epitendinous tenorrha-phy was biomechanically superior to either transpatellarand suprapatellar wiring techniques alone. These find-ings are likely explained by the synergistic relationshipbetween multiple forms of augmentation that allow loadsharing between components of the repair, which is alsosupported by greater stiffness using the combined wiringtechnique. A recent study by Soula et al. compared thebiomechanical properties of primary tenorrhaphies in acanine RPT model using a modified three-loop pulleytechnique and a three-level self-locking technique.11Although differences in study methodology make directcomparisons challenging, in our study, failure loads(mean ± SD) were greater (517.5 ± 80.8 N for transpatel-lar constructs, 489.1 ± 95.7 N for suprapatellar con-structs, 634.3 ± 156.1 N for combined constructs)compared to those reported for both the three-level self-locking technique (266 ± 85.6 N) and modified three-loop pulley technique (135 ± 70 N) reported in the Soulaet al. study.11Although direct extrapolation betweenstudies depends on a number of interrelated factors, thesuperiority of ancillary methods of stabilization usingTBW augmentation is apparent. These findings are likelydue to reduction in load placed on the primary tendinousanastomosis and load sharing between the primary tenor-rhaphy and TBW, which subsequently increases the loadsto cause construct failure.In humans, many surgical techniques for RPT repairaugmentation have been reported to mitigate the directforces placed upon the repair site during quadriceps con-traction and weight bearing. Methods described includethe use of either a transpatellar cable-wire cerclage orpolydioxanone sutures, autograft, or tendinous allografts(Semitendinosus, Achilles tendon), or use of sutureanchors.28–34Given the lack of available veterinary litera-ture, the results of the present study can be comparedwith similar biomechanical studies cited in the humanliterature. A biomechanical study by Rothfeld et al. com-pared primary RPT repair with augmentation using alocking Krackow suture pattern with an 18-gauge TBWor use of a multifilament internal brace with FiberTape(Arthrex, Inc., Naples, Florida).30In this study, aug-mented repairs using orthopedic wire or ultra-highstrength 2 mm FiberTape composed of long-chain poly-ethylene were superior to core RPT repairs alone with nodifference reported between different augmentationmethods (wire vs. FiberTape).30A human study by Ettin-ger et al. demonstrated that failure loads were greaterusing suture anchors compared to transpatellar augmen-tation using No. 2 Ultrabraid sutures (Smith & Nephew,Hamburg, Germany).32In humans, the biomechanicalsuperiority of internal splint augmentation has multipleclinical benefits such as the ab ility for earlier weightbearing and mobilization, controlled rehabilitation,and load application to the repair site, allowing for col-lagenous remodeling.30,32In patients undergoing RPTrepair, augmentation techni ques have been associatedwith decreased postoperative complications such asdecreased range of stifle motion and cartilage excoria-tion due to chondromalacia.1,5,29,35In the present study, construct failure was decreasedusing combined TBW augmentation in comparison witheither transpatellar or suprapatellar TBW use alone,with the predominant mode of failure seen to be due towire unraveling at the twist. Although wire breakage is awell-documented complication in veterinary literaturefollowing TBW implementation,3,4,7failure of orthopedicwire due to unraveling of the knot occurs when a singleincreasing load is applied. Wire breakage occurs due tocyclical loading, especially in instances where bendingforces are applied.3,4,7To date, there is a paucity of infor-mation reporting the true mechanism and location ofwire failure in veterinary patients. Modifications such asthe use of orthopedic wire with a greater area moment ofinertia, increased number of twists, or the location of thecompleted twists may all play a role in construct biome-chanics, and subsequently represent an area for investiga-tion. All primary tenorrhaphies were repaired using acore LL and SCES, due to evidence supporting the biome-chanical superiority of these techniques for anastomosis1146 MCKAY ET AL . 1532950x, 2023, 8, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14000 by Vetagro Sup Aef, Wiley Online Library on [15/11/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licenseof flat tendons.24,25,36Although weaker than the 3LPtechnique, the LL pattern leads to superior apposition ofthe tendon ends with less bunching at the anastomosissite.24,25,36Failure caused by core suture pull through canlikely be attributed to differing load application to therepair site rather than load application being primarilyresisted by the orthopedic wire. In several constructs,there were two concurrent modes of failure seen duringtesting, most notably caused by the wire first unravelingcausing subsequent suture pull through due to overload-ing of the primary tendinous repair. The incidence ofsuture pull through differed between transpatellar andsuprapatellar wire techniques being 22% greater in trans-patellar group. These findings are likely explained due tothe increased construct stiffness in the transpatellargroup due to the bone-to-bone interface of the wire caus-ing load application to the repair when the wire is loadedbeyond its elastic limit rather than relying on the inher-ent strength of native tissues. Lastly, fracture of thepatella was only noted in the combined group. Patellafractures occurring either alone or in combination withpatellar ligament rupture are often treated with a TBW todecrease forces generated during quadriceps contraction.1In a human cadaveric study by Bonazza et al., biome-chanically evaluating medial patellofemoral ligamentreconstruction, transosseous tunnels were associatedwith increased risk of patellar fracture if the anterior cor-tex of the patella was compromised during bone tunneldrilling.37This may be a possible explanation for thepatellar fracture in this study and warrants further studyas transosseous tunnel creation was performed in a sub-jective freehand manner to replicate what is performedclinically in our tertiary referral hospital.Resistance to gap formation is a crucial component ofthe tenorrhaphy during the postoperative period, as gapformation is associated with adhesion formation,impaired healing and collagenous remodeling, ultimatelyresulting in patella alta, decreased limb function, anddecreased joint range of motion.38Gap formation of lessthan 3 mm has been shown to lead to greater ultimateforce and rigidity postoperatively.38In our study, theoccurrence of gap formation was lower in the combinedwire augmentation group, further supporting the biome-chanical superiority of this combined technique asreported in the human literature.39,40In a human cadav-eric study by Ravalin et al., augmented repairs followingPT avulsion (No. 5 Ethibond suture or 2 –0 cable) resistedgap formation to a greater degree than primary tenorrha-phies alone.39Similarly, a study by Gould et al. foundthat simulated RPT repairs using a Krakow pattern aug-mented with suture tape were superior compared to pri-mary tenorrhaphy.40Although there were no differencesin the occurrence of gap formation among study groups,this may have been due to a small sample size resultingin Type II statistical error. In several instances, gappingbetween tendon ends was not recorded due to constructfailure prior to identification of a gap forming. Althoughthis makes data regarding the incidence of gap formationmore difficult to interpret, calculated loads at which gapformation occurred between tendon ends remainunaffected.The limitations of this study include the use of acadaveric model for biomechanical testing, which doesnot account for the effects of biological tissue healing orinflammatory mediators on collagenous remodeling.Similarly, use of linear distraction to failure testing with-out evaluation of cyclical loading likely underrepresentsthe complex and differential forces placed on the repairduring different phases of the canine gait cycle. Tendonrepairs will often fail within their reported range of toler-ance when experiencing cyclical loading rather than peakload application or load to failure.41In our study, PTwere sharply transected in the mid-substance region ofthe PT, in contrast with tendinous fraying and fibrildegeneration often seen in clinical cases. We used a sin-gle transosseous tunnel, through which both wires wereplaced in the combined group; the effect of drilling sepa-rate tunnels and its effect on construct biomechanics isunknown. Lastly, a reported concern regarding the use oforthopedic wire for adjunctive RPT repair stabilization iswire fatigue and breakage, resulting in lameness orsoft-tissue irritation ultimately necessitating removalpostoperatively.3,4,7,15A study by Das et al. reported agreater number of patients requiring surgical reinterven-tion to remove orthopedic wire versus use of monofila-ment nylon.4Despite these known complications, wirecontinues to be cited widely throughout the literature asa form of definitive fixation.1,3Future studies investigat-ing the use of materials for RPT augmentation, includingfiber wire and monofilament nylon, are warranted tocompare the biomechanical effects of each technique andultimately improve clinical outcomes.In conclusion, use of a combined transpatellar andsuprapatellar TBW technique using orthopedic wire as anadjunctive method of stabilization following primarycanine RPT repair was biomechanically superior to eithertranspatellar and suprapatellar wiring techniques aloneand was associated with a decreased incidence of failure.This combined adjunctive wiring technique, in additionto primary RPT repair, may offer a viable surgical optionfor increased repair-site strength. Further studies investi-gating alternative methods and materials for RPT repairaugmentation are warranted.AUTHOR CONTRIBUTIONSMcKay RM, DVM: Interpretation of the data, writing andrevising the manuscript, and approval of the final versionto be published. Duffy DJ, BVM&S(Hons.), MS, FHEA,MCKAY ET AL . 1147 1532950x, 2023, 8, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14000 by Vetagro Sup Aef, Wiley Online Library on [15/11/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseMRCVS, DACVS (Small Animal), DECVS: Design of workperformed and study methodology, construct suturing andwire augmentation, acquisition of data, interpretation ofthe data, writing and revising the manuscript, andapproval of the final version to be published. Chang Y-J,BVetMed, MS: Acquisition of data, interpretation of thedata, revising the manuscript, and approval of the finalversion to be published. Beamon W, DVM: Acquisition ofdata, interpretation of the data, revising the manuscript,and approval of the final version to be published. MooreGE, DVM, PhD, ACVIM (SAIM): Statistical analysis, inter-pretation of data, review of the manuscript and approvalof the final version to be published.FUNDING INFORMATIONNo funding was provided for the purposes of this study.CONFLICT OF INTEREST STATEMENTAuthors have no disclosures or conflicts of interest toreport. All veterinary orthopedic wire used in this projectwas kindly provided by Imex (Imex, Longview, Texas).This company had no role in the design of the study, datacollection and analysis, the decision to publish, or thepreparation of the resultant manuscript. The authorshave no financial interest in, or incentive in, the use ofImex veterinary products.ORCIDDaniel J. Duffy https://orcid.org/0000-0002-3043-8877

Answer 86

We found that our novel form of ureteroneocystostomy,ETSUTT, was technically feasible and safe to performand provided good clinical outcomes for feline proximalureteral obstruction. No cats experienced major postoper-ative complications, such as uroabdomen or persistentureteral obstruction, following ETSUTT. Compared withend-to-side ureteroneocystostomy, the use of side-to-sideureteroneocystostomy likely allowed better orientationfor surgical manipulation. Two-layer closure on side-to-side ureteroneocystostomy with three tension-relievingtechniques may have resulted in sufficient tension reduc-tion and a water-tight anastomosis.In the present study, relatively long survival timeswere achieved in most cats, which was consistent withother studies that examined ureteral surgery in cats withbenign ureteral obstruction.5,10,12,18,22No cats developedrecurrent ureteral obstruction during the follow-upperiod. Postoperative narrowing of the lumen may havebeen avoided by suturing the near side inner layer of thetwo-layer closure with a simple interrupted suture pat-tern rather than a simple continuous suture pattern.Another possible advantage of ETSUTT was that thewider anastomosis and remaining very short ureter mayhave allowed spontaneous passage of small nephrolithsinto the bladder.10One female cat voided three residualnephroliths shortly after surgery without further inter-vention. Due to the small number of cases, we cannotconclude that this was a possible beneficial effect and fur-ther investigation is needed.Placement of a SUB device is another treatment optionfor proximal ureteral obstructi on in cats, but postoperativecomplications, such as dysuria,16,20,22,27,28device occlu-sion16,21,22,27and postoperative UTI,20–23,26 –29can occur. Inthis study, 50% of the cats had postoperative complicationsfrom a SUB device, and ureteral patency was maintainedafter ETSUTT in all five cats. This result suggested that theETSUTT procedure was a viable option for cats with postop-erative complications associated with SUB device placement.In addition, by selecting ETSUTT as an initial treatment,implant-associated complications can be avoided, which isbeneficial especially for relatively young cats.Indications for ureteronephrectomy secondary to ure-teral obstruction include lack of any residual renal func-tion in the affected kidney, end-stage hydronephrosisconcurrent with severe infection, or severe, unsalvageableureteral injury.8,9Most importantly, ureteronephrectomyFIGURE 6 Kaplan –Meier survival curve for 10 cats withproximal ureteral obstruction. A solid line represents survival forcats treated using extravesicular, two-layer, side-to-sideureteroneocystostomy combined with tension-relieving techniques.Dashed lines represent 95% CIs. Censored data (still alive, n=7)marked as a vertical, short, black line.980 OYAMADA ET AL . 1532950x, 2023, 7, must be performed only when the contralateral kidney issufficiently functional. In this study, most cats were azote-mic and the contralateral kidneys were atrophic or absent;thus, ureteronephrectomy was not indicated.The renal pelvis diameters were decreased postopera-tively in all cats except one cat with a nephrostomy tubeplaced preoperatively. Based on the ultrasonographic find-ings and improved renal function parameters, the ureteralpatency and renal function on the operated kidneyappeared to be maintained after surgery. Mild renal pelvisdilation in some cats suggested that vesicoureteral reflux(VUR) may have occurred. Two cats had chronic pyelone-phritis after surgery, and their kidney disease progressedrapidly during the postoperative follow-ups (nos. 8 and 10;Table S1Serum creatinine concentrations over time),which may have been associated with VUR as reported indogs.35,36The owners of these cats did not consent to fur-ther workup, and we could not confirm the presence ofVUR. However, it is important to monitor for signs of UTIand pyelonephritis over the long term because they can bedeleterious to residual renal function.The limitations of this study included the small num-ber of cats and unstandardized postoperative treatments.More studies are necessary to refine this surgical techniqueand to determine appropriate postoperative treatment pro-tocols. In addition, we did not perform a contrast imagingdiagnostic to confirm the ureteral patency after surgeryeven though we carefully determined the presence ofpatency based on the ultrasonographic findings. Althoughwe performed this novel procedure in 10 cats, due to ana-tomical variation it may not be applicable in some cases.Taken together, this novel procedure, ETSUTT, wasfeasible, safe, and provided good clinical outcomes forfeline proximal ureteral obstruction, including the UPJ.This procedure may be especially suitable for obstructionscaused by ureteral stricture or occlusion of a SUB device.AUTHOR CONTRIBUTIONSOyamada K, DVM: Conducted the retrospective studyand drafted the manuscript. Inoue M, DVM and Sato-Takada K, DVM, DACVIM (SAIM): Reviewed and editedthe manuscript. Minamoto T, DVM, PhD: Reviewed andedited the manuscript and performed the statistical ana-lyses and interpreted the data. Fujiki M, DVM, PhD:Reviewed and edited the manuscript. All authors contrib-uted substantially to the conception or design of the workand approved the final version of the manuscript andagree to be accountable for all aspects of the work inensuring that any questions related to the accuracy orintegrity of any part of the work are appropriately investi-gated and resolved. The authors thank LAMAN for illus-trating the figures and BioScience Writers for Englishlanguage editing.FUNDING INFORMATIONThe authors received no financial support for theresearch, authorship, and/or publication of this article.CONFLICT OF INTEREST STATEMENTThe authors declare no conflicts of interest related to thisreport.ORCIDKazuhisa Oyamada https://orcid.org/0009-0008-6231-8870Tomomi Minamoto https://orcid.org/0000-0002-6245-2382

Answer 87

This retrospective study on 15 cats that were presentedconsecutively for bilateral SILF stabilization with thetransiliosacral toggle suture repair system demonstratedFIGURE 3 Postoperative first follow up (50 days) and last follow up (682 days) ventrodorsal radiographs of case 10. This cat had thelongest follow up available. Some remodeling of both sacroiliac joints is present at 682 days. Perfect bone tunnel alignment (right and leftiliac vs. sacral) without tunnel widening illustrates lack of sacroiliac displacement during follow up in this case. Complete healing of pubicand ischial fractures can also be noted, without overt callus formation, which could be an indication of a relatively stable construct.TABLE 2 Summary of owners'answers for their cats ’ability to performsome activities. AbilityScore12345Walking 0 0 1 1 10Running 0021 9Rising from a resting position 0 0 0 1 11Lie down 0 0 0 1 11Ability to stretch 0 0 0 1 11Ability to jump up 1021 8Ability to jump down 1011 9Climbing stairs ( n=11) 0 0 0 1 10Descending stairs ( n=11) 0 0 0 1 10Playing with toys 0 0 1 1 10Chasing objects 0111 9Playing with other pets (if applicable) ( n=8) 0 0 1 0 7Grooming 0 0 1 1 10Interaction with owners 0 0 0 1 11Ability to touch the cat's lower back (stroking,brushing, etc.)0024 6Ability to squat for urination/defecation 0003 9Eating 0 0 0 0 12Note: Score interpretation: (1) Unable to perform the activity; (2) the injury often interferes with thisactivity; (3) the injury sometimes interferes with this activity; (4) the injury hardly ever interferes with thisactivity; (5) the injury never interferes with this activity.988 FROIDEFOND ET AL . 1532950x, 2023, 7, a good-to-excellent clinical and radiographic outcome inour population. The purpose of this technique, in com-parison with previously reported ones, is to preserve themotion of the sacroiliac joint. Its range of motion isunknown in cats but has been reported to be of 1.5 –7.0/C14in rotation in the sagittal plane, 1.0 –1.4 mm craniocaud-ally, and 0.6 –0.7 mm latero-medially in dogs (GermanShepherd dogs and Greyhounds).16Performing a rigidstabilization of this joint is considered to be withoutimportant consequences, although the sacroiliac jointplays a central role in weight-bearing and transmission ofpropulsive forces. The elastic properties of muscle tissue,tendons, ligaments and cartilage play an important rolein the distribution of propulsive forces, minimizing stressand tissue damage. Sacro-iliac joint elasticity thereforeplays a role in the reduction of stress concentration atspecific points such as the hip joint, extrinsic pelvic limbmuscles or the lumbosacral junction for example. Transi-liosacral toggle suture repair for bilateral SILF has thebenefit of trying to restore an elastic sacroiliac joint com-pared to other reported techniques. Although the sacroil-iac joints do not have substantial mobility, they are at theforefront in the transmission of forces to the whole body.Maintaining their elasticity would allow them to regain afunction as close to normal physiology as possible,although documenting this benefit would be complex. Inthe long term, this preserved motion could be interesting,with potentially better preservation of surrounding struc-tures involved in ambulation and less development ofdegenerative changes or injury-related disease. Sacroiliacdiseases are well recognized in humans23and likelyunderdiagnosed in small animals although it has beendescribed in active working dogs, with a high radio-graphic prevalence (85%).24The clinical significance ofthese findings is still to be evaluated. Sacroiliitis of proba-ble infectious origin has also been reported in dogs inseveral case reports with various presentations, oftenincluding pelvic limb lameness.25,26Indications for the nonsurgical management of uni-lateral SILF are felines being ambulatory, with displace-ment of less than half of the sacroiliac joint surface,maintained comfort, absence of neurological deficitsand/or < 45% narrowing of the pelvic canal.27One caseseries described overall excellent long-term owner-reported outcomes for 12/13 cases treated conserva-tively.27Nevertheless, narrowing of the pelvic canal canlead to long-term chronic constipation or dystocia, andsurgical management of SILF is therefore most-oftenrecommended for bilaterally affected cats, ischial and/orpubic fractures being commonly reported. By restoringnormal anatomy and providing immediate stability, a fas-ter recovery is expected, with better short-term functionaloutcomes and an improved level of early comfort. Severalopen surgical techniques have been described in thetreatment of feline SILF with dorsal or ventralapproaches,28,29as well as various types of internal fixa-tion (lag screw(s), transiliac pins, tension band).3,17,30Most studies reported stabilization of feline SILF with acortical screw inserted in lag fashion to allow both stabil-ity and restoration of a satisfactory pelvic canalwidth.3,6,9,18,19,31Increasing screw purchase into thesacral body to 60% of its width has been recommended toreduce the risk of implant loosening.32,33In bilaterallyaffected cats, avoiding conflict between right and leftscrews without compromising screw diameter or lengthcan be challenging, especially without intraoperativeimaging examination. It can therefore easily lead to mal-positioning of a screw, protruding into the sacral or pelviccanal, which could be associated with iatrogenic damageand/or reduced resistance to pull-out forces. To overcomethe risk of inadequate sacral drilling, the placement ofthe transiliac implant has been described with good clini-cal results reported for unilateral feline SILF treatment inone study.30,34In that study 2/6 cats were also treated forbilateral SILF, one of which suffered major implant-related complications (biomechanical failure). In a seriesof 25 dogs with six bilaterally affected cases, transilialpinning was performed with a good overall outcome.35However, two of the bilaterally affected dogs had pooroutcomes due to long-term nerve damage. From thesedata, and although no objective comparison exists betweentrans-sacral and non-trans-sacral stabilization techniquesfor bilateral SILF treatment, it is commonly accepted thattransiliac stabilization should not be used as a sole methodof stabilization for bilateral SILF.30Placing a single implant across the entire transiliosa-cral length, stabilizing both sacroiliac joints together, hasalso been reported. The bilateral simultaneous approachof both sacroiliac joints for open reduction allows thesimultaneous direct observation of the center of bothsacroiliac joints. The use of an aiming device for trans-sacral drilling is therefore possible, thus minimizing therisk of implant mispositioning. Previous studies reporteda satisfactory implant positioning in the sacral safe corri-dor and good to excellent clinical outcome.4,8,10,13,15Implant positioning was previously thoroughly evaluatedradiographically with measurement of the cranial or cau-dal AoD.15The mean AoD that we report as an absolutevalue in our study of 3.1 ± 2.8/C14(/C07.2/C14caudally to+7/C14cranially) is within the range of their results of +1.6/C14(/C02.3/C14to+7.5/C14). It confirms the good to excellent cranio-caudal orientation of the sacral corridor in our popula-tion. We decided to report the absolute value rather thannegative and positive ones as the amount of deviationwas considered more relevant than the direction of thedeviation. The use of a custom 3D-printed guide has beenFROIDEFOND ET AL . 989 1532950x, 2023, 7, reported recently in the treatment of unilateral canineSILF and demonstrated a mean craniocaudal deviation of4.2 ± 3.9/C14, which is somewhat similar to our results.36Bilateral access possibly improved surgical accuracy inour population. Lateral radiographs were always consis-tent with implant positioning in the sacral body,although titanium buttons prevented accurate evaluation.A postoperative CT-scan evaluation would be requiredfor a precise assessment of tunnel positioning. However,the authors believe that direct observation of the correctanatomic placement of the bone tunnel entry and exitpreclude the absolute need for systematic postoperativeCT-scan evaluation.Objective measures described to assess surgical reduc-tion were PCWR to evaluate pelvic canal narrowing andPoR to assess craniocaudal reduction. A PCWR >1.1 issuggested to prevent secondary chronic constipation.20For feline bilateral SILF surgical stabilization, previousstudies reported mean postoperative PCWR values of 1.4and 1.21, respectively, for transiliosacral pinning or tran-siliosacral screw and nuts.13,15The results reported forour population were comparable with an immediate post-operative mean of 1.24 ± 0.08. One cat had a postopera-tive PCWR <1.1 (1.03) but did not develop chronicconstipation in the long term. An important finding withregards to PCWR is that no change was noted over time.The absolute immediate postoperative PoR valueswere measured at 88.1% and 91.0% on the right and leftside, respectively, in our population, which is comparablewith previously reported results at 91%,17,1895%,15and92.3%.19From these measurements, we can conclude thatthe technique reported in our study allows good ana-tomic restoration and repositioning of both iliac wings inmost cases. Malreduction is always by default. Substantialdigital caudal pressure applied onto both iliac wingsalongside counterpressure on either side of the tail basewas performed in the last cases of the series to aidreduction, with subjectively, if not better, at least easierreduction, than that achieved by only tightening the pros-theses to 20 N. Tunnel entry in each sacral wing wasjudged ideal for most cases during surgery by the sur-geon. The iliac tunnel exit onto the medial aspect is moredifficult to assess and may be responsible for the 9% to12% of malreduction in our population. Improving iliactunnel placement, SILF reduction, and prosthesis ten-sioning would be the main topics to refine the surgicaltechnique and improve PoR.The mean PCWR at 6-week recheck was 1.23, withno substantial movement in comparison with postopera-tive measures. Despite the absence of statistical signifi-cance, a slight cranial displacement of the pelvic wingson one ( n=3) or both sides ( n=4) was observed, with-out functional consequence noted (p-value of .17 and .56respectively for left and right PoR - Table 1). The slightchanges in PCWR and PoR over the initial few weeks arelikely related to the relative flexibility of the system(slack) and, possibly, the lack of complete realignment ofthe three bone tunnels in relation to insufficient tension-ing of the system. Surprisingly, this finding has also beenpreviously reported in dogs with a subjectively more rigidstabilization with lag screw.18Intraobserver variabilityand/or the cat's positioning for radiographs may also con-tribute to the small differences observed over time. Theideal tension that should be placed on the prosthesis stillrequires to be studied. Compressing both iliac wingsagainst the sacrum with pointed bone reduction forcepswhile tightening the sutures could potentially alsoimprove the stability of the construct as well as favoringthe realignment of both hemipelvii in cases where theywould be uncoupled by pubic/ischial fractures. It wouldbe interesting to evaluate, on a larger population, theimpact of such additional fractures on postoperativemobility of both hemipelvii and the impact of additionalsurgical stabilization, such as transilial pining, on the riskof mechanical complications. Surgical stabilization of pel-vic floor factures has been reported in cats and could alsobe performed towards achieving an even better and fastermechanical and functional recovery.29Recent studieshighlighted the interest of fluoroscopically guided tech-niques in the treatment of SILF in dogs and cats, whichare associated with better anatomical reduction andimplant positioning, as well as less implant looseningthan conventional open techniques.5,6,12,14,18,19,31,37 –40Surgical time also appears subjectively shorter withclosed reduction and lag screw fixation of unilateral SILF(6–16 minutes).38–40The technique described in ourstudy could potentially be performed with a minimallyinvasive approach under fluoroscopic guidance. Surgerytime for single trans-sacral screw and nut stabilization ortransiliosacral pin were previously reported at 70 minutes(55–90 min) and 90 minutes (80 –112 minutes) respec-tively.13,15Mean surgical time of 80 minutes (50 –120 min) reported in our population is therefore subjec-tively similarly comparable to these previously reportedopen techniques for SILF surgical treatment.The overall clinical and functional results in the felinepopulation reported are good to excellent, with excellentquality of life reported by the owners. A nearly full returnto normal activity for all cats for which long-term followup was available was also reported without any neurolog-ical dysfunction, including urinary/fecal incontinence.The complication rate in our population was low (7%,n=1). Surgical site infection or tunnel widening wereneither identified nor reported during the follow-upperiod. Interestingly, the medium-term radiographs(n=7) at a median of 205 (71 –682) days postsurgery still990 FROIDEFOND ET AL . 1532950x, 2023, 7, did not show any radiographic sign of sacral tunnel wid-ening. Undersized drilling at 2 mm of diameter comparedto 2.7 mm recommended by manufacturer for thisimplant, the small amount of motion on these joints aswell as constructs with unidirectionally applied tensionare all factors that may contribute to this absence of tun-nel widening. Despite being extensively discussed amongveterinary surgeons, the reports of surgical site infectionand/or tunnel widening are comparatively infrequent inthe literature.41–43The two most recent studies reportingthe use of TightRope in the treatment of coxofemoral lux-ation reported a rate of 3% (1/32) and 0% infectionrespectively and 0% and 77% tunnel widening with only30% of 5 mm or more.41,42Nevertheless, these specialconcerns have to be assessed thoroughly in longer term,larger cohort studies.Using a single point of fixation for each sacroiliac joint,physiological rotational motion in the sagittal plane is pre-served. It should be mentioned that this method of fixationbecomes less applicable on its own in cases of completesacral wing fracture.22In terms of planning, it highlightsthe potential interest of a preoperative CT-scan, which hasbeen proven to be more accurate than radiographs todetect canine sacral fractures.44Three cats in our studysuffered type I sacral fracture, without any clear conse-quences for the various outcomes that were measured.Most limitations of our study are related to its retro-spective nature. The surgical procedure and follow upwere, however, standardized. Most of the data wereacquired retrospectively with the associated potentialbias mainly including underestimation of the complica-tion rate. The use of an owner-based questionnaire hasbeen widely reported and validated for follow-up out-come assessment in cats but still relies heavily on theowner's assessment, with a high level of subjectivity andas u b s t a n t i a ll a c ko fr e s p o n s i v e n e s sd e s p i t er e a s o n a b l ereliability.21The case series was small, which preventedam o r em e a n i n g f u ls t a t i s t i c al analysis. The absence of asubstantial number of complications meant that riskfactors could not be evaluated. The technique reportedhere is a derivation of the initial intended use for theTightRope system. In the absence of mechanical failure,the mini-TighRope seems suitable for medium-sizedcats, as illustrated by our population (2.87 –5.75 kg). Bio-mechanical studies are required to assess its biomechan-ical behavior in this configuration and the impact ofsuture tensioning on overall stability. It would also beinteresting to look for a cut off in terms of patientweight to decide between mini or standard TightRopesystems. Larger cohort clinic al studies with comparisonamong different treatment methods are still required toevaluate the further complications rate, identifypotential risk factors, and advantages of this techniquecompared to previously published ones.This study supports the clinical efficiency of transilio-sacral toggle suture repair in the treatment of feline bilat-eral SILF. The anatomic restoration was good toexcellent, with overall excellent functional outcomes inour population. Longer term evaluation is still requiredto confirm that degenerative/inflammatory sacroiliitis ortunnel widening should not be a concern.ACKNOWLEDGMENTSAuthor Contributions: Froidefond B, DVM: Contrib-uted to data acquisition and analysis, drafted, revised,and approved the submitted manuscript. Moinard M,DVM: Contributed to data acquisition, revised andapproved the submitted manuscript. Caron A, DVM,DECVS: Developed the surgical technique, contributed tothe study design and data analysis, drafted, revised, andapproved the submitted manuscript.CONFLICT OF INTEREST STATEMENTAlexandre Caron is a paid consultant for Arthrex.ORCIDBaptiste Froidefond https://orcid.org/0000-0002-9220-8997

Answer 88

Off-label use of Nocita for incisional infiltration at the time of closure of gastrointestinal surgery is becoming increasingly common in veterinary medi -cine. The information presented in this manuscript is novel and builds upon previously published work regarding incisional infections and the use of Nocita for abdominal procedures. This was the largest-scale study to date evaluating the rate of SSIs in dogs re -ceiving Nocita for gastrointestinal surgery and the only study to do so in cats. The overall SSI rate was 5.8% in dogs receiving Nocita for gastrointestinal sur -gery, compared to 10.2% for dogs that did not re -ceive Nocita in this study. The SSI rate among cats that received Nocita for gastrointestinal surgery was 3.6%, compared to 4% for those that did not receive Nocita. Not only was there no association between higher infection rates and administration of Nocita, but the infection rates presented here mirror pub -lished rates of SSIs for clean-contaminated surger -ies.4 As a result, the authors propose that the use of Nocita following gastrointestinal surgery poses no increased risk for the development of an SSI in both dogs and cats.No dogs that received Nocita after dirty gastro -intestinal surgery due to septic peritonitis developed an SSI. Although there was a larger population of pa -tients presenting with preoperative septic peritonitis that did not receive Nocita (n = 9) than those that Groups Subjects SSI Percentage (%)Nocita 124 7 4.2No Nocita 87 9 10.2Totals 211 16 8Table 1 —Canine surgical site infection (SSI) frequency after clean-contaminated gastrointestinal surgery.Fourteen canine patients, 5 of which received Nocita and 9 of which did not, presented with preop -erative septic peritonitis. Of these patients, 1 of 14 (7%) was diagnosed with an SSI and 1 (7%) was diag -nosed with septic peritonitis postoperatively. Both of these patients did not receive Nocita at the time of gastrointestinal surgery. None of the 5 (0%) patients with preoperative septic peritonitis that were admin -istered Nocita developed a superficial SSI (Table 2) .Table 2 —Canine SSI frequency after gastrointestinal surgery for septic peritonitis.Groups Subjects SSI Percentage (%)Nocita 5 0 0No Nocita 9 1 11Totals 14 1 7Of the canine patients that developed SSI, the most common surgical indication was a foreign body obstruction making up 15 of 16 (93%) of incisional in -fections in this study. Eight of 16 (50%) underwent a gastrotomy, which represented the most common pro -cedure of those canine patients that developed SSI.Three of 78 (3.8%) feline patients were diagnosed with SSI. Two of 55 (3.6%) feline patients that re -ceived Nocita were diagnosed with an SSI, compared to 1 of 23 (4%) of those that did not receive Nocita. No feline patients were diagnosed with preoperative or postoperative septic peritonitis. All feline patients diagnosed with an SSI underwent surgery for a for -eign body obstruction. Of feline patients that devel -oped an SSI, 2 underwent 2 or more procedures not including an intestinal RA and 1 cat underwent an enterotomy (Table 3) .Table 3 —Feline SSI frequency after clean-contaminated gastrointestinal surgery.Groups Subjects SSI Percentage (%)Nocita 55 2 3.6No Nocita 23 1 4Totals 78 3 3.8Postoperative antibiotic useThirty-eight of 211 (18%) canine patients were discharged with antibiotics. Specific antibiotics that were prescribed at the time of discharge included Unauthenticated | Downloaded 12/24/23 09:37 AM UTC 5did receive Nocita (5), the rate of SSI reported here in patients presenting with septic peritonitis is much lower than previously published rates of wound complications in contaminated surgeries in which patients received Nocita.9 On the basis of this infor -mation, the authors suggest that the use of Nocita in dirty gastrointestinal surgery presents a low risk for the development of SSIs in dogs and cats; however, further prospective clinical trials are indicated to fur -ther investigate its use in these cases.Isolates of aerobic culture and antibiotic sensi -tivity were recorded. In both dogs and cats, the most common isolates were similar to those previously re -ported, most commonly normal gastrointestinal flora (E coli , Enterococcus , and more).3 It was noted, as was reported previously, that many of the isolates were resistant to the perioperative antibiotic used in surgery and commonly prescribed antibiotics for SSIs (Clavamox and cefalexin). While an MDR bacte -rium was grown from the dog that received Nocita, MDR bacteria were also isolated in most of the cases in dogs that did not receive Nocita. Our study sug -gests that MDR bacteria are very commonly cultured from SSI of both canine patients that receive Nocita and those that do not. A larger study population is needed to determine whether MDR pathogens are more commonly isolated from patients that received Nocita at the time of gastrointestinal surgery.Interestingly, the majority of canine patients that developed an SSI, regardless of administration of Nocita, presented for foreign body obstructions. It is unclear whether this indicates that there is a higher risk of developing an SSI following surgery to retrieve a foreign body, given the limited number of cases that developed an infection. Given that the bacteria isolated from infections in this study were consistent with native gastrointestinal flora, sug -gesting that they are secondary to contamination at the time of surgery, it stands to reason that there may be increased spillage or contamination of tis -sues when retrieving a foreign body through a small incision into a hollow viscus compared to resecting a portion of an intestine for a gastrointestinal tumor that traditionally is performed with the use of atrau -matic clamps to prevent spillage. Further studies are needed to investigate the association between indi -cation for surgery and development of an incisional infection as well as the specific location of gastro -intestinal tract operated on and development of an incisional infection.Limitations of this study were inherent in its ret -rospective nature. Because of the retrospective na -ture of this study, the method in which Nocita was administered was unable to be standardized. While on-label use describes instillation of the drug either as a 4-point nerve block for onychectomy in cats or using an “infiltration injection technique” following tibial plateau–leveling osteotomy surgery in dogs, no such guidelines exist for administration following abdominal surgery. Some surgeons have reported injecting only into the subcutaneous tissues, while others report injecting into the rectus sheath as well. This was unable to be evaluated in this study. Additionally, the volume or method of postoperative lavage following the gastrointestinal-specific portion of surgery was unable to be appropriately quanti -fied or standardized. While it is currently standard practice for the authors to lavage the subcutaneous tissues prior to closure, this was not something that was able to be assessed in this patient population and the potential impact of differing quantities or methods of lavage are unknown. Patient selection for Nocita administration was also not standardized and represents a potential source of bias. Additionally, few cultures were performed following diagnosis of an incisional infection. As a result, interpretation of the impact that administration of Nocita has on the bacterial population of incisional infections and pres -ence of multidrug resistance is limited. Anaerobic cultures were also not routinely performed in these patients, so it is impossible to know the impact that opportunistic or commensal organisms had in the development of a postoperative infection. Further -more, active surveillance was unable to be achieved due to its retrospective nature such that diagnosis of an SSI was dependent on owner observation and diagnosis at a follow-up appointment. In addition to this, the CDC states that SSIs may be diagnosed up to 30 days postoperatively. However, follow-up in veterinary surgical patients is often limited to 10 to 14 days. Many large-scale veterinary and human epi -demiological studies of wound infection have used the presence of purulent discharge within 14 days as the definition of an infected wound; however, there is the possibility that SSIs were underdiagnosed as a result.1,14–17 It is impossible to know what proportion of these patients had incisional infections outside of the study period but still within the time frame dictated by the CDC and how it would have altered our results. Lastly, the inoculation techniques and specifically count of bacteria that a microbiology lab deems as significant growth were not standard -ized across the 2 institutions in this study, such that a small degree of growth at 1 institution may have been inappropriately disregarded.Overall, we found no evidence that Nocita leads to higher rates of SSIs, septic peritonitis, or growth of more MDR bacteria than in dogs and cats not receiving Nocita for both clean-contaminated and dirty gastrointestinal surgery.4 The rates of SSIs of dogs and cats receiving Nocita are lower than pub -lished SSI rates for both clean-contaminated and dirty surgery. Further prospective clinical trials are needed to assess the impact of Nocita administra -tion in a wide variety of surgeries and determine the influence of Nocita on the presence of MDR infec -tions. Future study directions may include blinded, randomized clinical trials comparing the effect of no incisional block, traditional bupivacaine line blocks, and Nocita for the development of SSI and growth of MDR bacteria.AcknowledgmentsNone reported.Unauthenticated | Downloaded 12/24/23 09:37 AM UTC6 DisclosuresThe authors have nothing to disclose. No AI-assisted technologies were used in the generation of this manuscript.FundingThe authors have nothing to disclose.

Answer 89

In this study, removal of the axillary lymph nodes by anMIS technique in the small number of cases reported wasfeasible and associated with minimal complications. Themain axillary node is situated adjacent to the axillaryartery and vein and brachial plexus in a relatively inac-cessible location due to the overlying forelimb muscula-ture. Subjectively, the endoscopic technique facilitatedvisualization of these hazards compared with an openapproach. The technique might be further refined withthe addition of an indocyanine green fluorescence tech-nique to aid the intraoperative identification of the nodeswithin the surrounding fat18,19and thus accelerate surgi-cal times. Indocyanine green fluroscence has been usedin this manner both for sentinel node mapping19and alsofor optimizing node identification.20The correct placement of the SILS port was importantin creating a successful operating space. Due to adiposetissue present in the region, if the SILS port was placedtoo deep, the axillary lymph node and associated adiposelayer relocated to the roof rather than the floor of theviewing window when the axilla was inflated with gas.Thus, if the landmarks are identified and the lymph nodecannot be located, the clinician should probe the dorsalregion caudal to the axillary artery and vein. In one ofthe clinical cases performed, it was necessary to convertto an open approach due to difficulties grasping the nodeand elevating it away from its position adjacent to thevascular bundle. This was likely due to an excess of cau-tion on the part of the operator, although an articulatingdissector might also have made this easier.At our institution, ultrasound guided fine needle aspi-rates of locoregional nodes are routinely performed aspart of our neoplastic staging protocol when the nodescannot be readily palpated for palpation guided aspirates,or if palpation guided aspirates yield nondiagnostic samples.However, in select cases we have also started mapping thesentinel lymph node by indirec tC Tl y m p h a n g i o g r a p h yf o l -lowed by surgical excision and histopathology due to datasuggesting improved sensitivity for detection of metastaticdisease.21This has been particularly helpful in guidinginformed decision making when surgical excision/ recon-struction of the primary tumor would require a large surgi-cal dose. However, an unanticipated outcome of thischange in protocol is that we have found our mapping tak-ing us to the axillary lymphocenter more frequently thanpreviously. In our experience, this has been a deeper dis-section requiring more retraction than other cutaneous lym-phocenters. This has proved an incentive to identify a lessinvasive method of excision that provides good visualizationof necessary landmarks. The su ccess rate of unassisted sur-gical localization of lymph nodes by open techniques hasbeen reported at 72%,22implying room for improvement.Combining an MIS technique with a localization techniquemay help achieve the optimal balance between patientrecovery, minimal postoperat ive complications, and suc-cessful lymph node retrieval.While lymphedema is a common complication afterdissection of the axillary nodes in human patients, we didnot observe this as a complication. This might be due toaccessory lymphatic channels in the canine species, orthe small number of clinical cases assessed. Suami et al.23found that lymphatic breaks created by lymph node dis-section in a canine model repaired and restored via col-lateral pathways to second tier lymph nodes in theregion. Similarly, to our knowledge, no case developedpneumothorax or pneumomediastinum as a complicationof insufflation in this area. This has also not beenreported as a complication following endoscopic axillarydissection in the human patient population,14,24presum-ably because the dissection does not need to extend intothe thoracic wall.While we were unable to identify previous reports ofan endoscopic approach to noncavitary lymph noderetrieval in the veterinary literature, a human endoscopicsentinel lymph node biopsy and endoscopic axillary lym-phadenectomy study without liposuction demonstratedthat this approach was feasible, had a low complicationrate and samples obtained were comparable to thoseachieved with an open dissection.14Based on our experi-ence in the clinical cases reported, some discomfort onperi-incisional palpation and mild lameness may beanticipated in the immediate postoperative period andshould resolve over the next couple of days post proce-dure. Proper analgesia needs to be provided.Limitations of this study include the small samplesize and limited number of surgeons performing the pro-cedure. All the clinical cases were large breed dogs and894 KUVALDINA ET AL . 1532950x, 2023, 6, the technique may be more challenging in smalleranimals.In conclusion, this study demonstrated that a mini-mally invasive approach to the axilla and subsequentvisualization of the axillary node is possible and can beutilized in those patients in which an excisional biopsy ofthe axillary lymph node is required. A controlled studywith more patients is required to determine whether thehypothesized benefits of an MIS approach compared withan open technique can be verified.AUTHOR CONTRIBUTIONSKuvaldina AB, DVM: Assisted with study design, dataacquisition and interpretation; paper draft, revisions, andfinal approval; agrees to be accountable for all aspects ofthe work in ensuring that questions related to the accu-racy and integrity of any part of the work are appropri-ately investigated and resolved. Buote N, DVM, DACVS:Assisted with study design, data acquisition and interpre-tation; paper revisions, and final approval; agrees to beaccountable for all aspects of the work in ensuring thatquestions related to the accuracy and integrity of any partof the work are appropriately investigated and resolved.Luis Campoy L, LV, Cert VA, DipECVAA, MRCVS:Assisted with study material acquisition; paper finalapproval; agrees to be accountable for all aspects of thework in ensuring that questions related to the accuracyand integrity of any part of the work are appropriatelyinvestigated and resolved. Porter I, DVM, DACVR:Assisted with study design and study material acquisi-tion; paper revisions, and final approval; agrees to beaccountable for all aspects of the work in ensuring thatquestions related to the accuracy and integrity of any partof the work are appropriately investigated and resolved.Hayes GM, BVSc, PhD, DACVS, DACVECC: Created thestudy design, assisted with data acquisition and interpre-tation; paper draft, revisions, and final approval; agreesto be accountable for all aspects of the work in ensuringthat questions related to the accuracy and integrity of anypart of the work are appropriately investigated andresolved.CONFLICT OF INTERESTThe authors declare no conflict of interest related to thisreport.ORCIDNicole Buote https://orcid.org/0000-0003-4623-3582Galina M. Hayes https://orcid.org/0000-0002-1365-3284

Answer 90

The present report described a case of functional paraganglioma of the gall bladder. In a report of 13 cases of canine neuroendo -crine carcinoma of the gall bladder, immunohistochemistry of the tumour tissue was strongly positive for synaptophysin and gastrin antibodies in all cases of Zollinger- Ellison syndrome (O’Brien et al. 2021 ). The present case was strongly positive for synaptophysin, but only 10% of cells were positive for gastrin antibodies. Furthermore, the dog did not present Zollinger- Ellison syndrome symptoms, such as vomiting and haemateme -sis, which may indicate atypical features of gall bladder tumours. It is possible that the difference between the dog in our study and those reported in the study by O’Brien et al. (2021 ) was due to the fact that this dog had a functional paraganglioma, while pre -viously described dogs actually had functional neuroendocrine carcinomas secreting gastrin.Additionally, the preoperative dynamic CT contrast scan showed a strong contrast effect in the arterial phase and con -trast washout in the delayed phase, consistent with the contrast pattern reported in adrenal pheochromocytoma (Yoshida et al. 2016 ). The imaging findings suggested that the patient’s mass had abundant blood flow, which could indicate a neuroendocrine neoplasm or paraganglioma.The dog had a hypertensive crisis associated with mass manip -ulation during surgery, which persisted until the tumour was devascularised. This typical sign noted in this dog was similar to hypertensive crisis in dogs with pheochromocytoma. The urinary normetanephrine to creatinine ratio is a useful diagnostic exami -nation for catecholamine- producing tumours ( i.e. pheochromo -cytoma) in dogs (Quante et al. 2010 , Salesov et al. 2015 , van den Berg et al. 2023 ). In a report of retroperitoneal paragangliomas in dogs, two cases had symptoms of hypertensive crisis (Gombert et al. 2022 ), but did not meet the diagnostic criteria for pheo -chromocytoma. The urinary normetanephrine to creatinine ratio in the present case was sufficiently high (21,420 – preoperatively) compared to reports of functional adrenal pheochromocytoma in dogs (Quante et al. 2010 , Salesov et al. 2015 ). Additionally, urinary catecholamine metabolites were greatly reduced postop -eratively, strongly suggesting catecholamine production by the gall bladder tumour in this case. It was a limitation that urine collection was performed under anaesthesia to determine the normetanephrine to creatinine ratio, thus, potentially affecting the concentrations of catecholamines and their metabolites.Based on the imaging findings, pathological diagnosis and urinary normetanephrine to creatinine ratio, the gall bladder tumour in this case was a paraganglioma, which is classified as a neuroendocrine neoplasm. The presence of paraganglionic tis -sue in the gall bladder has been previously reported in humans (Kawabata 1999 , Xia et al. 2023 ).In the present case, the gall bladder mass showed severe adhe -sions to the surrounding area and abundant blood flow. Since a preoperative biopsy of the tumour was not obtained, a divisio -nectomy of the central hepatic division include the gall bladder was performed. We considered this resection technique appro -priate as it involved the fewer vessels and did not require dissec -tion of the gall bladder, and thus decreased the risk of having incomplete margins. Additionally, the dog had good prognosis after complete resection, indicating that surgery may be benefi -cial for long- term survival in cases of neuroendocrine carcinoma of the gall bladder.There have been no previous reports of functional tumours in dogs arising from extra- adrenal sources, including the gall bladder. In the present case, preoperative CT angiography and urinary catecholamine measurements revealed findings similar to those of a functional pheochromocytoma. Most canine gall blad -der neuroendocrine neoplasms are gastrin- producing tumours. However, the risk of functional paraganglioma should be consid -ered when approaching canine gall bladder tumours.Table 1. The preoperative and postoperative values of urinary catecholamines and metanephrines to creatinine ratiosParameter Pre Post Reference of canine PC (Salesov et al. 2015 )Norepinephrine:Cr 3763 29 8 to 2687Epinephrine:Cr 235 17 2 to 914Normetanephrine:Cr 21,421 117 467 to 12,472Metanephrine:Cr 2669 89 134 to 4576Postoperative day 93, PC Pheochromocytoma, Cr Creatinine 17485827, 2024, 2, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jsap.13665 by Vetagro Sup Aef, Wiley Online Library on [04/02/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseH. Horikirizono et al.Journal of Small Animal Practice • Vol 65 • February 2024 • © 2023 British Small Animal Veterinary Association. 148Author contributionsHiro Horikirizono: Conceptualization (lead); data curation (lead); formal analysis (lead); investigation (lead); methodology (lead); project administration (lead); supervision (equal); writ -ing – original draft (lead); writing – review and editing (lead). Munekazu Nakaichi: Formal analysis (supporting); methodol -ogy (supporting); project administration (supporting); super -vision (equal); writing – original draft (supporting); writing – review and editing (supporting). Harumichi Itoh: Conceptu -alization (supporting); data curation (supporting); formal analy -sis (supporting); investigation (supporting); writing – original draft (supporting). Kazuhito Itamoto: Data curation (support -ing); investigation (supporting); project administration (support -ing); writing – review and editing (supporting). Yuki Nemoto: Data curation (supporting); investigation (supporting); writing – original draft (supporting); writing – review and editing (sup -porting). Hiroshi Sunahara: Data curation (supporting); formal analysis (supporting); investigation (supporting). Kenji Tani: Methodology (supporting); writing – original draft (supporting); writing – review and editing (supporting).Conflict of interestNone of the authors of this article has a financial or personal relationship with other people or organisations that could inap -propriately influence or bias the content of the paper.

Answer 91

Based on the ﬁndings of our study, we accepted our hypoth-esis that a long working length would result in low constructstiffness in compression bending and torsion, and high platestrain in compression bending. We partially rejectedour second hypothesis, however, with a greater plate –bonedistance resulting in lower construct stiffness in torsion only,but a higher plate strain was observed for greater plate –bonedistance under compression bending. The results of ourstudy support the previously published literature on plateworking length, showing that a long working length haslower construct stiffness in a fracture gap model comparedwith a short working length under both bending and tor-sional loads.2–4,12Furthermore, our study has demonstratedthat plate strain over the fracture gap was signi ﬁcantly lowerin constructs with a short working length. This ﬁnding isconsistent with previous published studies.2–4,12,14Working length was the major determinant of constructstiffness and strain, with plate –bone distance only having adetectable effect in torsional loading, where overall stiffnessof the constructs was much less than in bending loads. Witheach incremental increase in working length, constructstiffness was lower in both bending and torsion, and platestrain was higher in bending. Historic controversy aroundthe effect of working length stems from the results of a 1-mmfracture gap model in a ﬁnite element analysis study,4wheretranscortical contact during construct loading produced loadsharing. In this 1-mm fracture gap model, a longer workinglength paradoxically resulted in high stiffness subsequent totranscortical contact and consequently lower plate strain.Somewhat surprisingly, this led to the recommendation toincrease working length in narrow fracture gap scenarios tofacilitate early transcortical contact. In an in vivo situation,however, repetitive transcortical contact would, in theabsence of plastic deformation of the plate, result in unsus-tainably high interfragmentary strain of 100%. This wouldnecessitate bone resorption and widening of the fracture gapto attempt to reduce interfragmentary strain to a levelcompatible with the production of ﬁbrous tissue.6,15,16Whether fatigue implant failure would then occur in thissituation in vivo would depend on the biologic capacity of thefracture site, the fatigue life of the implant, and the frequencyand magnitude of cyclic loading. Given the results of ourstudy, and other recently published evidence, it is reasonableto conclude that a construct with a longer working lengthwould be at greater risk of implant failure than a constructwith a shorter working length.2–4,12,14Our study shows no effect of increasing plate –bone dis-tance in bending. Under torsional loading, however, incre-mental increases in plate –bone distance in short and longworking length constructs resulted in signi ﬁcantly lowerstiffness. For medium working length constructs, however,increments in plate –bone distance did not signi ﬁcantly affectstiffness. We consider the absence of difference for mediumworking length constructs is most likely the result of type IIerror.In our model, any effect of increasing plate –bone distancewas not detected in four-point compression bending. Thisdiffers from previous studies4,9where a signi ﬁcant reductionin stiffness in axial compression was noted when plate –bonedistance was greater than 2 mm. Both of the cited studiesutilized axial compression for bending, which creates atensile load on the plate, which differs from the compressionbending induced in our study. Many previous biomechanicalstudies evaluate tension bending and/or axial compression,as these are considered to mimic physiologic forces on afracture repair due to the eccentric position of bone platesrelative to the mechanical axis of long bones.4,6,7,9,10,17,18Table 3 Mean surface strain on the plate at the level of the fracture gap (mm/mm, reported /C210/C05) across working lengths andplate –bone distance in compression bendingShort working length Medium working length Long working lengthPlate –bone distance of 1 mm 358ad(95% CI: 324 –392)636bcd(95% CI: 582 –690)476e(95% CI: 387 –565)Plate –bone distance of 1.5 mm 344ad(95% CI: 297 –390)648bcd(95% CI: 579 –716)711b(95% CI: 628 –794)Plate –bone distance of 3 mm 354ad(95% CI: 279 –429)608c(95% CI: 518 –697)698b(95% CI: 627 –768)Abbreviation: CI, con ﬁdence interval.Note: Means with the same superscript are not signi ﬁcantly different ( p/C200.05)..Loading of fracture gap models in this mode causes thefracture gap to close at the trans-cortex. In constructs withlow stiffness, this can result in contact between the bonemodel fragments, causing load sharing between the bonecolumn and implants.4,19Furthermore, tension bending canalso result in plate –bone contact at the level of the fracturegap, which reduces the working length de ﬁned by screwposition to a working length equivalent to the fracturegap.19,20Given that our study aimed to evaluate a trueload-bearing construct with working length as a primaryexplanatory variable, we elected to test compression bendingto prevent any bone –bone or bone –plate contact duringtesting, which could confound results.Both compression and tension bending induce both bend-ing and shear loads on the exposed shaft of the screw, with agreater plate –bone distance increasing the length of screwshaft exposed to these loads. Axial compression results in anonuniform bending moment, with greater bendingmoments experienced at the center of the construct. Thisincreases the shear and bending loads on the screws, whichwill magnify the effect of increasing plate –bone distance inaxial compression. In the locking plate study by Ahmad andcolleagues,9implant failure through screw head looseningwas identi ﬁed in three samples, which for locking constructsis critical for maintaining the strength of the implant. As aresult, this may have resulted in the reduction in constructstiffness noted with increasing plate –bone distance in axialcompression in that study.A previous study10evaluated both bending and axialcompression using dynamic compression plates, and identi-ﬁed a greater magnitude of stiffness reduction with increas-ing plate –bone distance in axial compression compared withfour-point bending. Since dynamic compression plates wereused, these ﬁndings cannot be directly applied to the modelused in the present study; however, they highlight theimportance of experimental design and load conditions onconstruct stiffness. Axial compression and four-point com-pression bending differ in the bending moment produced,with a uniform bending moment in four-point compressionbending compared with three-point tension bending pro-duced through axial compression. The nonuniformity of thebending moment, and the subsequent increase in bendingand shear loads experienced by the screws may explain whyconstruct stiffness has differed for the same constructs underaxial compression versus four-point bending in previousstudies.While no effect of plate –bone distance on stiffness wasdetected in compression bending, a signi ﬁcant effect onstiffness was noted in torsion, with a plate –bone distanceof 3 mm resulting in signi ﬁcantly reduced torsional stiffness.Reduced torsional stiffness with greater plate –bone distancehas previously been demonstrated in larger locking plates(4.5- and 5.0-mm LCP), with plate –bone distances greaterthan 2 mm shown to have signi ﬁcantly decreased torsionalstiffness and lower overall loads to failure.4,9,17Thedecreased torsional stiffness of implants with a greaterplate –bone distance can be attributed to the increasinglength of exposed screw shaft being less resistant to torsionalforces compared with axial forces.9,10Our results demonstrated a signi ﬁcant interactionbetween working length and plate –bone distance, with acompounded reduction in stiffness noted for the longestworking length and the greatest plate –bone distance. Thesame construct con ﬁguration was also identi ﬁed to have thehighest plate strain in compression bending. This interactionwas more evident under torsion testing, where the effect of along working length could be modulated by a low plate –bonedistance. While not evaluated in the current study, we wouldhypothesize that minimizing the plate –bone distance in along working construct would also reduce plate strain intorsion. While this is a biomechanical model rather than aclinical study, these results suggest that when the fractureconﬁguration forces the use of a longer working length,efforts should be made to minimize the plate –bone distanceto optimize construct stiffness. Knowledge of the interactionbetween a long working length and a higher plate –bonedistance may necessitate consideration of augmenting therepair to ensure adequate stiffness.In our model, working length was the overwhelmingdeterminant of construct stiffness and plate strain, withplate –bone distance only a signi ﬁcant factor in torsionalloading. A long working length results in lower constructstiffness in compression bending and in torsion, and resultsin higher plate strain in compression bending. A signi ﬁcantinteraction between working length and plate –bone dis-tance in torsion shows that using a small plate –bone distancecould modulate the loss of stiffness and increase in strainproduced by a long working length.

Answer 92

Based on the previously described literature search, this report is the first to focus on the conservative management of gastro -intestinal metallic sharp- pointed straight foreign bodies in dogs and cats. Conservative management following a metallic sharp- pointed straight object ingestion was reported in only one dog in a previous retrospective case series of needle ingestion (Pratt et al. 2014). In our study, conservative management was adopted in 17 cases, either as a primary approach or following failure of endoscopic or surgical retrieval and none of the patients reported complications.The majority of cases in this study were younger than 2 years of age consistent with a previous report where the median age of the cats and dogs with sewing needle foreign bodies was 1 year (Pratt et al. 2014). Witnessed ingestion of a sharp- pointed for -eign body with no clinical signs was the most common reason for presentation accounting for 82.3% of the cases; therefore, it was known for how long the foreign body had been within the gastro -intestinal tract. Clinical signs on presentation possibly related to the foreign bodies were reported in three dogs (including vomit -ing, lethargy, anorexia, diarrhoea and abdominal pain). Although these clinical findings are consistent with those described in previous retrospective studies in dogs and cats with sewing needle foreign body ingestion and cats with gastrointestinal linear foreign bodies (Felts et al. 1984, Basher & Fowler 1987, Pratt et al. 2014), the frequency of clinical signs in this study was much lower compared to the population described by Pratt et al. (2014). Indeed, all the cats in this study were asymptomatic compared to the 63.8% of cats with clinical signs related to the sewing needle foreign body described by Pratt et al. (2014). This difference is likely due to the exclusion of patients with foreign bodies located outside of the gastrointestinal tract which meant that patients with pharyngeal and oesophageal foreign bodies were not described, as well as those where a presumed migration of the foreign body from the gastrointestinal tract had occurred. However, some clinical signs related to the presence of the for -eign body may have been missed.Based on the ESGE guidelines in people, emergent or urgent endoscopic removal of oesophageal and gastric sharp- pointed for -eign body is recommended as the risk of complications (e.g. per -foration) can be as high as 35% (Birk et al. 2016). If endoscopy is not successful, daily radiographic follow- up is recommended; once the foreign body has entered the jejunum, 80% to 85% will be expelled within 72 hours (Birk et al. 2016, Becq et al. 2021). Endoscopy was reported to be successful in retrieving foreign bodies of any type from the upper gastrointestinal tract (orophar -ynx, oesophagus and stomach) in 95% of cases in humans (Becq et al. 2021). In our study, endoscopy was attempted on initial presentation in seven cases but was unsuccessful in three patients. Endoscopic success for retrieval of foreign bodies was reported to be 90.2% in a study on oesophageal and gastric foreign body removal in dogs (Gianella et al. 2009) and 92.9% in a study on sewing needles ingestion in dogs and cats (Pratt et al. 2014). Lower success in this study may have been due to exclusion of oropharyngeal and oesophageal foreign bodies. Endoscopic fail -ure was reported to be related to the presence of large amount of ingesta which did not allow visualisation of the foreign body in two cases, while the foreign body had moved into the small intestine during the procedure in the third case. 17485827, 2023, 8, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jsap.13606 by Vetagro Sup Aef, Wiley Online Library on [07/08/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseC. Crinò et al.Journal of Small Animal Practice • Vol 64 • August 2023 • © 2023 The Authors. Journal of Small Animal Practice published by John Wiley & Sons Ltd on behalf of British Small Animal Veterinary Association.526Human guidelines recommend that, if a sharp- pointed for -eign body is seen within the intestine, frequent radiographic follow- up should be performed to monitor the progression of the foreign body and surgery should performed if the patient develops clinical signs or if the foreign body fails to move within 72 hours (Birk et al. 2016, Becq et al. 2021). Based on human data, surgery is required in less than 1% of cases after foreign bodies ingestion (Becq et al. 2021). Interestingly, two cases in this study had surgery performed as the foreign body failed to progress on repeated radiographs performed after 24 hours. Con -sidering human guidelines, it could be argued that performing surgery in these cases was premature and that more time should have been allowed before deciding the conservative approach was unsuccessful. In addition, the mean faecal transit of foreign body in this study of 59.2 (±31.4) hours, consistent with findings of a retrospective study on linear foreign body in cats (Basher & Fowler 1987), would support this assumption. Based on these findings and human guidelines, a time frame of 72 hours could be considered before performing surgery; however, further veteri -nary studies will be needed to confirm that a similar time frame is safe and could be recommended in veterinary patients.Complications such as mucosal ulceration, perforation and peri -tonitis, abscess, haemorrhage and fistula formation, and migration outside the gastrointestinal tract are reported in 1% to 5% cases of sharp foreign body ingestion in human medicine, with most com -plications occurring secondary to oesophageal foreign bodies (Becq et al. 2021). In a human prospective study, 29.5% of cases devel -oped complications related to the presence of the foreign body, but 89.5% of these foreign bodies were oesophageal and only 1.9% of the complications were observed for gastric foreign bod -ies; one gastric perforation occurred in a patients 12 hours after ingestion of eight sewing needles (Chaves et al. 2004). In our study, none of the cases reported showed signs of gastrointestinal perforation clinically and there was no evidence of this during endoscopy or surgery when performed. This is in contrast with a previous retrospective study where the rate of perforations was reported to be 17.2% (Pratt et al. 2014). In the abovementioned study, however, the majority of perforation were noticed in the oropharynx or oesophagus, with only two out of 26 (7.7%) dogs and cats with a needle in the stomach or intestine reported to have a perforation and it is unclear whether these patients had witnessed needle ingestion and therefore how long the needle had been in the patients’ bodies. Pharyngeal and oesophageal foreign bodies were not included in this study as these always undergo emergency endoscopy at our institution, due to associ -ated patient discomfort and the high risk of perforation or foreign body migration meaning conservative therapy is not appropriate.The present study has several limitations. Due to the retrospec -tive nature of the study, some information was not always recorded including the reason for the primary surgical approach in some cases and also whether the foreign body had passed from the body. In addition, further information regarding the supportive care provided as part of the conservative management may have not been recorded. Concomitant presence of linear foreign bodies (i.e. thread attached to a needle) was not specifically assessed in this study and different recommendations likely apply to these cases. Another limitation was that the study was performed in a tertiary referral hospital, and the cases analysed may not be reflective of the entire population. Finally, the number of patients enrolled in this study was relatively low; larger, possibly prospective, studies are required to investigate the indications, complications, rate of suc -cess and outcome of conservative management of gastrointestinal straight metallic sharp- pointed foreign bodies.In conclusion, the results of this study suggest that conservative management may be considered as a treatment option for straight metallic sharp- pointed gastrointestinal foreign bodies in dogs and cats in the absence of clinical signs consistent with, or evidence of, gastrointestinal perforation, and was successful in 15 of 17 patients in our study. Close monitoring and repeated radiographs should be considered to monitor the progression of the foreign body.AcknowledgementsAll authors approved the manuscript and its submission to the Journal of Small Animal Practice and have contributed signifi -cantly to the preparation of this manuscript, in keeping with the latest guidelines of the International Committee of Medical Jour -nal Editors.Author contributionsC. Crinò: Conceptualization (equal); data curation (lead); formal analysis (lead); investigation (lead); methodology (lead); valida -tion (equal); visualization (equal); writing – original draft (lead); writing – review and editing (equal). K. Humm: Conceptual -ization (equal); data curation (supporting); formal analysis (sup -porting); investigation (equal); methodology (equal); supervision (equal); validation (equal); visualization (equal); writing – origi -nal draft (equal); writing – review and editing (equal). S. Cor -tellini: Conceptualization (equal); data curation (supporting); formal analysis (supporting); investigation (equal); methodol -ogy (equal); supervision (equal); validation (equal); visualization (equal); writing – original draft (equal); writing – review and editing (equal).Conflict of interestNone of the authors of this article has a financial or personal relationship with other people or organisations that could inap -propriately influence or bias the content of the paper.

Answer 93

These results indicate that the risks of VBO in chronic OMI cannot confidently be balanced by an assurance that clinical problems will resolve after surgery. A significant proportion of cats showed resolution of NP signs, OE, purulent aural discharge and pruritus/alopecia, demon -strating clinical benefit. However, clinical signs did not resolve in a sizeable minority of cats. This might have been owing to chronic turbinate damage in some cats, as well as irreversible changes in the external, middle and inner ear.Our analysis did not identify viable predictors of complications or negative outcomes. The association of OI with persistent OE, but not other outcomes, is of limited value. Although generalists had worse outcomes for persistent OE compared with specialists, outcomes for other variables were similar. This suggests that this sur -gery can be successfully performed by a skilled generalist.Feline OM may be underdiagnosed.17 The most obvi -ous signs are head tilt and polyps, which were absent in more than half of the cats in our study. It was striking that most cats showed no inappetence at presentation, despite clinical rhinitis. This contrasts with the typical presenta -tion of acute URI, in which lethargy and inappetence are common.24 OMI should be considered a differential in cats with rhinitis and normal appetite, particularly if there is little response to an appropriate first-line antibiotic.OE is generally uncommon in cats compared with dogs,25–27 but was common in cats with OMI in our study and others.13 OE is likely to be secondary to OMI in cats, while the opposite is the case in dogs.1 While few cats were tested for ear mites because of routine use of selamectin, only 3/7 were positive. Dark, crumbly Table 2 Surgical complications after 88 ventral bulla osteotomies in 58 cats with otitis media-interna, transferred from an institutional hoarding environmentComplication Considered serious? After first surgery (n = 58) After second surgery (n = 30)None 18 (31) 11 (37)Any complication 40 (69) 19 (63)Serious complication 17 (29) 10 (33) Life-threatening perioperative complications Cardiac arrest Y 3 (5.2) 0 Dyspnea/upper airway obstruction – no tracheostomy/ventilationY 2 (3.4) 1 (3.3) Dyspnea/upper airway obstruction – tracheostomy/ventilationY 1 (1.7) 0 Severe hemorrhage Y 0 0 Early postoperative complications (within 2 weeks)* Acute wound infection N 1 (1.7) 0 Aspiration pneumonia Y 2 (3.4) 0 Congestion/cough/wheeze Y 2 (3.4) 1 (3.3) Nystagmus N 1 (1.7) 1 (3.3) Horner's syndrome N 35 (60) 17 (57) Otitis interna Y 5 (8.6) 3 (10) Head tilt/excursions 4 (6.9) 3 (10) Ataxia 4 (6.9) 3 (10) Meningoencephalitis† Y 1‡ (1.7) 0 Prolonged complications (persisted >2 weeks postoperativelya Alopecia/pruritus* Y 6 (10) 3 (10) Chronic wound infection Y 0 0 New anorexia (>1 week duration) Y 2 (3.4) 4 (13) Xerostomia, ‘brown tongue’ Y 0 3 (10) Number of complications 65 36 Number of serious complications 34 22Data are n (%)*New or markedly worse†An additional cat developed presumed meningoencephalitis 2 months postoperatively (see text)‡Based on a retrospective case review, was likely to have been present before surgeryaOther than new anorexia6 Journal of Feline Medicine and Surgery exudate ‘typical’ for ear mites can be a presenting sign of OM.1 Routine in-house microscopy should be performed on all cats presenting with OE. Negative results should increase suspicion of OMI.Cytology and culture of myringotomy samples are useful diagnostic tools in middle-ear disease, but the primary diagnosis of otitis media is based on otoscopic examination and imaging.2,28 Confirmation in our study relied heavily on radiographs. This may have biased case selection toward more severe cases. Radiography has lower sensitivity for diagnosis of OM compared with CT or MRI,29–33 but radiographic diagnosis is feasible in chronic cases, in which changes can be striking (Figure 1). Bulla wall thickening is the most readily identifiable change. In our study, a scoring system using wall thick -ness, asymmetry and tympanic cavity opacity (data not shown) did not offer advantages over scoring bulla wall thickening alone. Correct positioning and interpretation of bulla radiographs are essential and require appro priate training.Prolonged anorexia occurred after six surgeries and was associated with xerostomia and brown discolora-tion of the tongue in three cats that had bilateral VBOs. The most likely mechanism is hyposalivation and altered taste sensation through iatrogenic damage to the chorda tympani nerve.34 Bilateral nerve damage would explain the occurrence of xerostomia only after the second surgery, as unilateral nerve function would presumably have been adequate after a single surgery. People report loss of taste, loss of taste acuity, or an unusual or bitter Figure 2 Xerostomia and brown discoloration of the tongue, gingiva and mucosa overlying the hard palate after ventral bulla osteotomy in a cat. Note the dry appearance of the oral cavityTable 3 Resolution of clinical abnormalities at the veterinary recheck approximately 4 weeks after the final VBO, in 58 cats with otitis media-interna, transferred from an institutional hoarding environmentBefore VBO Recheck after VBO P value n Absent PresentInappetence Absent 46 (81) 4 (7.0) 0.50 57Present 6 (11) 3 (5.3)Pruritus/alopecia Absent 24 (43) 3 (5.4) 0.001 56Present 19 (34) 10 (18)Moderate/severe nasopharyngeal signs Absent 29 (53) 2 (3.6) 0.002 55Present 16 (29) 8 (15)Moderate/severe otitis externa Absent 9 (16) 2 (3.6) <0.001 55Present 32 (58) 12 (22)Purulent auraldischargeAbsent 33 (60) 2 (3.6) 0.002 55Present 16 (29) 4 (7.3)Horner’s syndrome Absent 26 (49) 26 (49) <0.001 53Present 1 (1.9) 0Otitis interna Absent 27 (50) 4 (7.4) 1.00 54Present 5 (9.3) 18 (33)Head tilt/excursions Absent 30 (54) 4 (7.1) 1.00 56Present 3 (5.4) 19 (34)Ataxia Absent 52 (93) 3 (5.4) Discordant cells too small 56Present 1 (1.8) 0Data are n (%). Data in cells shaded green (Present-Absent) and yellow (Absent-Present) were used in the McNemar test. Statistically significant P values are shown in bold type.Green = resolved after VBO; orange (Present-Present) = did not resolve; VBO = ventral bulla osteotomy; yellow = developed after VBOJacobson et al 7Table 4 OR* risk analysis for key negative outcomes, approximately 4 weeks after final VBO, in 58 cats with otitis media-interna, transferred from an institutional hoarding environmentModerate/severe nasopharyngeal signs at recheckModerate/severe otitis externa at recheck Clinical signs of otitis internaat recheck n OR 95% CI P value n OR 95% CI P value n OR 95% CI P valuePreoperative variablesFIV-positive 55 2.75 0.67–11.2 0.16 55 2.05 0.58–7.24 0.27 54 0.49 0.14–1.67 0.25Moderate/severe nasopharyngeal signs – – – – 55 1.41 0.42–4.77 0.58 53 0.54 0.18–1.64 0.27Moderate/severe otitis externa 55 0.50 0.11–2.39 0.39 – – – – 54 0.78 0.11–2.98 0.72Purulent aural discharge 55 0.71 0.16–3.10 0.64 55 2.15 0.63–7.42 0.22 54 0.29 0.08–1.04 0.06Ruptured tympanic membrane 33 0.18 0.02–1.71 0.14 33 1.60 0.33–7.65 0.56 32 2.10 0.49–9.00 0.32Polyp 55 0.86 0.19–3.79 0.84 55 0.47 0.11–1.97 0.30 54 2.50 0.78–7.97 0.12Moderate/severe bulla wall thickening 51 0.77 0.19–3.15 0.72 51 1.31 0.38–4.50 0.67 50 0.38 0.11–1.24 0.12Otitis interna 55 0.64 0.15–2.82 0.56 55 4.35 1.21–15.70 0.02 – – – –SEZ cultured 47 1.80 0.39–8.27 0.45 47 2.67 0.61–11.70 0.19 46 1.08 0.33–3.56 0.90Surgical variablesTwo VBO surgeries 55 10.29 1.20–88.07 0.07 55 0.86 0.26–2.91 0.81 54 1.06 0.36–3.15 0.92Generalist surgeon 55 3.69 0.89–15.27 0.07 55 3.64 1.03–12.87 0.045 54 1.77 0.56–5.57 0.44*Odds ratios reflect risk of the outcomes listed compared with absence of these outcomes. Values in bold are statistically significant.CI = confidence interval; OR = odds ratio; FIV = feline immunodeficiency virus; SEZ = Streptococcus equi suspecies zooepidemicus; VBO = ventral bulla osteotomy8 Journal of Feline Medicine and Surgery taste after chorda tympani damage,34 and this might have contributed to anorexia after the first VBO in two cats. Dysbiosis secondary to xerostomia and antibiotics was suspected to have caused yeast overgrowth and brown discoloration of the tongue in three cats.Although stress, allergic skin disease or parasites might have caused pruritus/alopecia, generalized pruri -tus was observed in this group of cats to a greater extent than is typically seen in this shelter and occurred in the face of broad-spectrum parasiticide products. Local dis -comfort probably caused pruritus in some cats, while generalized pruritus may have been owing to undiag-nosed allergic skin disease in others. In OMI cases with persistent and generalized pruritus, feline hyperesthesia syndrome could be considered if an allergy work-up is negative. This has been reported in a cat with OMI and ME.35The decision to proceed with surgical management was typically based on a lack of response to medical management, as well as the assumption that moderate/severe bulla wall thickening would not respond ade-quately to medical treatment. This assumption remains untested. Additional reasons for pursuing surgery were previous experience with chronic OMI and concern for progression to ME. ME was rare in our study, and occurred as a postoperative complication, suggesting that surgery is not always protective. In the shelter setting, barriers to adoption, adopter expectations and future financial burden are also key considerations. However, given that VBOs did not always result in substantial clini-cal improvement, the prevalence of serious surgical com -plications is concerning.Life-threatening perioperative complications, as also reported elsewhere,19,21,22 indicate that particular atten-tion must be paid to anesthetic and postoperative airway management. Preoperative dexamethasone may reduce airway swelling,22 and is advisable in the absence of contra indications. Staging of bilateral VBOs appears to be safer for severe and chronic OMI, but substantially adds to the cost and duration of treatment.OI did not resolve in most cats. Improvement was noted at some postoperative rechecks, but the data were not uniform enough to allow analysis. In previous reports, neurological improvement was reported in three-quarters of cats treated medically and all cats treated surgically,18 but OI did not fully resolve in any cat.16 Postoperative OI occurred in eight cats. This complication has been reported previously,16,17,19 and results from damage to sensitive structures and, possibly, extension of infection after surgical manipulation. More conservative osteot-omy could be considered, but in the authors’ experience (CP , PR), this may be insufficient and require revision, as occurred in three early cases in this series.Concurrent FIV-positive status was not a negative prognostic indicator. This is important, because both FIV and OMI prevalences are high in some groups of hoarded cats.10 Bilateral disease requiring bilateral VBO was expected to be associated with worse outcomes, but this was not the case. Clinical SEZ infection in cats is associated with animal hoarding and can cause chronic upper and lower respiratory tract infection, OMI and ME.8,35–37 Surprisingly, a positive SEZ culture had no significant association with negative outcomes. This suggests that inflammatory changes, dysbiosis38 and Table 5 OR* risk analysis for serious complications and euthanasia after VBO in cats with otitis media-interna, transferred from an institutional hoarding environmentSerious complications Euthanasia n OR 95% CI P value n OR 95% CI P valuePreoperative variablesFIV-positive 58 0.75 0.23–6.80 0.63 58 1.54 0.23–10.13 0.65Nasopharyngeal disease 57 2.77 0.92-8.32 0.07 57 0.84 0.13–5.46 0.86Otitis externa 58 2.11 0.50–8.84 0.31 58 1.05 0.11–10.34 0.97Purulent aural discharge 58 1.38 0.46–4.15 0.56 58 2.92 0.45–19.06 0.26Ruptured tympanic membrane 35 1.09 0.27–4.50 0.90 35 0.53 0.05–5.68 0.60Polyp 58 0.83 0.27–2.55 0.74 58 3.18 0.48–20.81 0.23Moderate/severe bulla wall thickening54 0.67 0.22–2.04 0.48 54 0.75 0.12–4.91 0.77Otitis interna 58 0.42 0.13–1.32 0.14 58 0.35 0.04–3.37 0.37SEZ cultured 48 3.40 0.97–11.98 0.06 – – – –Surgical variablesTwo VBO surgeries 58 2.19 0.74–6.50 0.16 58 0.60 0.09–3.86 0.59Generalist surgeon 58 0.83 0.27–2.55 0.74 58 1.30 0.20–8.47 0.79*Odds ratios reflect risk of serious complications or euthanasia, compared with their absenceCI = confidence interval; OR = odds ratio; FIV = feline immunodeficiency virus; SEZ = Streptococcus equi suspecies zooepidemicus; VBO = ventral bulla osteotomyJacobson et al 9chronicity may play a greater role than the specific organism identified.Middle-ear infection is, in effect, an abscess in an inac -cessible site, and this limits the value of systemic medi -cations. Therapeutic myringotomy, flushing and topical therapy have been recommended.1,2,26 Despite cautions to the contrary,3 myringotomy may be feasible without specialized equipment, but requires skill and can result in complications. There is no primary peer-reviewed literature to support the effectiveness of therapeu-tic myringotomy and flushing in chronic feline OMI. Inflammatory tissue, chronic infection and the bony sep -tum that greatly restricts access to the medioventral com -partment of the feline tympanic cavity are likely to reduce the effectiveness of flushing and topical medication in chronic cases. Even if effective, multiple treatments might be required. Myringotomy was not attempted in our set -ting, primarily because of lack of confidence that these cases could be successfully treated in this way. In a recent study, medical management with a single myringotomy and flush, glucocorticoids and antibiotics was successful in 17/24 cats with OM.39 However, severity, chronicity and criteria for success were not addressed in this pre-liminary report.Could chronic medical management be reasonable in chronic OMI? Cats in our study typically had no obvi-ous evidence of discomfort. Cats with OI were gener -ally mobile and active, with disabling ataxia or head tilt being uncommon. It might be feasible to manage such cases conservatively, with treatment goals of avoiding progression and managing problematic NP signs and OE. One motivation for surgical management of OMI is the risk of extension of infection to the brainstem. Although ME was common in an older case series,40 it is no longer a frequently reported complication,35,41 and may be amenable to medical treatment.35,41,42 Chronic rhinosi-nusitis (RSS) can be managed medically,43 and this could form a blueprint for chronic OMI. Surgical management could be reserved for cases with quality-of-life concerns that might reasonably be expected to be alleviated by surgery.This study was limited by its retrospective nature and the extraordinary difficulties of managing complex indi -vidual cases within a large group setting. The extent of improvement of ataxia and head tilt was not codified, and these would have been useful data. The assess -ment of the clinical success of VBO was limited by per -petuating factors for OE in a few cats and presumed, or CT-confirmed, RSS in a greater number. This reflects the reality that chronic RSS is part of the feline chronic upper respiratory disease complex.Studies directly comparing different treatment approaches to chronic feline OMI would be of immense value. Groups of hoarded cats with OMI would present an ideal opportunity to compare medical and surgical approaches to OMI, with potentially lifesaving, resource-sparing results. However, such studies would be complex and expensive.ConclusionsThe surgical management of chronic OMI was success-ful in many cases, but it was not benign, and not always beneficial. The improvement of signs of OI is a reasonable treatment goal, while full resolution is less likely. Serious complications, including some that were life-threatening and others that compromised welfare and were highly resource-intensive, were quite frequent. No viable predictors of surgical and overall outcomes could be identified. Conservative medical management of OMI could be considered, with surgery reserved for cases in which there is quality of life that might reasonably be expected to be ameliorated by VBO.Acknowledgements We thank PetSmart Charities Canada, Toronto Veterinary Emergency Hospital, Veterinary Emergency Clinic, IDEXX Laboratories, Dr Zeny Feng and Dr Tim Nuttall for their assistance. Thanks are also extended to the staff, management and Board of Toronto Humane Society for their dedication and support.Supplementary material The following files are available as supplementary material:File 1: Examination template for cats following ventral bulla osteotomy, File 2: Classification of clinical features of otitis media-interna, and dichotomous groupings used for statistical analysis.

Answer 94

The sleeve cuff of the sterile surgical gown is consideredunsterile after the surgeon's hands have passed throughit.18During a CGE, a scrubbed member is ungloved bypulling the gloves off and concurrently pulling the gowncuff over the hands in order to don a new pair of sterilegloves in a closed gloving manner. For these reasons, wehypothesized that CGE would result in a greater numberof positive hand cultures when compared with the num-ber of positive cultures obtained at baseline of the surgi-cal team's hands. We rejected our hypothesis as we foundno statistical difference between bacterial hand contami-nation pre-CGE and post-CGE. We did not find any asso-ciation between post-CGE bacterial hand contaminationand service, participant training level, scrub type, timespent scrubbing, or length of surgery participation.A recent study found that performing a CGE did notincrease bacterial contamination on the outside ofgloves.22The study differed from the present study in thelocation of cultures (outside cuffs and gloves) and thetiming of cultures. The Sidhu group assessed CGE bycomparing the culture results obtained from the outsidecuffs of freshly donned gowns and gloves to cultureresults obtained from the outside gown cuffs at the com-pletion of surgery and gloves following CGE at the com-pletion of surgery. As mentioned above, this group foundno difference in the bacterial contamination rate of gowncuffs prior to, and after, surgery. Further, they found nodifference in bacterial contamination rate of gloves pre-operatively and following regloving. The Sidhu groupshowed that the outside of the cuff and the outside of thegloves were not different in contamination before andafter CGE but did not evaluate the surgeons' hands, leav-ing a surgeon wondering about the impact of CGE on thesurgeon's hands should a glove puncture occur followingglove exchange. Our study shows that hands inside thegloves had no difference in bacterial contamination ratesbefore and after CGE, allowing the surgeon even moreassurance regarding CGE.Newman et al.19performed a study to assess contami-nation of gowns following three different glove-donningtechniques. They assessed open, closed, and assistedglove exchange using UV lotion applied to the surgeons'fingertips to represent contamination. The group foundTABLE 7 Results of univariable logistic regression model onpositive culture.Oddsratio95% confidenceinterval p-valueService 1.265 0.846 –1.891 .25Training level 0.855 0.584 –1.251 .42Scrub type 1.389 0.252 –7.640 .71Time spentscrubbing (s)1.004 0.990 –1.017 .58Length of surgeryparticipation (min)1.002 0.993 –1.010 .65Note: Services evaluated: general surgery, soft tissue, oncology, neurology,orthopedics; training levels evaluated: faculty, student, resident, intern,technician; Scrub types evaluated: Sterillium, Avagard; surgical procedure.TABLE 8 Results of multivariablelogistic regression model on positiveculture.Odds ratio 95% confidence interval p-valueService 1.262 0.841 –1.893 .26Training level 0.890 0.611 –1.297 .54Scrub type 1.004 0.165 –6.103 1.00Time spent scrubbing 1.005 0.991 –1.020 .46Length of surgery participation 1.003 0.984 –1.022 .80FIGURE 2 Summary of isolated bacteria.752 BIEHL ET AL . 1532950x, 2023, 5, that assisted glove exchange never resulted in gown con-tamination whereas open and closed glove-donningtechniques each resulted in gown contamination in100% of the trials.19There are differences between theNewman study and the present study, including methodof detecting contamination and assessment of the handsthemselves versus the gown. Both of these studies evalu-ated the outside of the gown or gloves for contamina-tion. In the present study, bacterial contamination wasassessed by culture methods comparing pre-glove-exchange hand culture resul ts to post-glove-exchangehand culture results while the Newman study used UVlotion to represent bacterial contamination. This differ-ence in methodology may be the reason that the New-man group found that CGE resulted in gowncontamination 100% of the time while the present studyfound no difference in contamination of the handsthemselves. Based on the present study and the study bySidhu et al.,22CGE does not result in more bacterialcontamination of the surgeon's gloves or hands and theUV lotion contamination may not be representative ofbacterial contamination.An interesting finding from the present study is thatsome members of the surgical team had positive handcultures at the baseline culture when the team memberwas about to scrub out of surgery. Positive hand culturesfollowing surgery have been reported in other studies.Eklund et al. found that 64% of surgeons' hands had posi-tive cultures immediately after the operation.8The grouptheorized that following the surgeon's scrub, the sur-geons' hands were recolonized by the bacteria multiply-ing in the crypts of sebaceous glands and hair follicles.8In the present study, 7.5% of the baseline cultures of thehands at the end of the surgical procedure werepositive –much lower than the 64% mentioned above.Eklund et al. cultured the hands of surgeons followingcardiac surgery, which involved long surgical procedureswith an average duration of 194 minutes. In the presentstudy, the mean length of surgical participation was129 min, possibly explaining the difference in incidenceof positive cultures. Further, the method of culture in thepresent study was different from the method used by theEklund group, in which they cultured the tips of the par-ticipants fingers by dipping them in petri dishes contain-ing 10 mL of saline. The nailbeds are known to have ahigher number of bacteria than any other areas of thehand,23possibly contributing to the higher rate of posi-tive cultures found in the Ecklund study.Interestingly, the length of participation in surgerywas not found to correlate with increased incidence ofpositive hand cultures in the present study. This findingmay have been the result of a Type II error. Previousstudies have shown that participants in surgeries of lon-ger duration are more likely to have high hand bacteriacounts likely due to increased replication of bacteria.8,24We suspect that duration of surgery was not associatedwith increased incidence of positive hand cultures in thepresent study because the durations of procedures in thepresent study were shorter than durations in previousstudies. In the present study, the average duration of sur-gical participation was 129 min. In a study by Hosseiniet al., bacterial recolonization of a surgeon's hands wasdetected at 300 min.24It is therefore possible that anincreased level of hand contamination was not detectedbecause a majority of the surgical procedures in the pre-sent study did not pass a threshold of 300 minutes. Ifmore surgical procedures were included with varyingdurations of procedures it is possible that a differencewould have been detected.The bacteria most commonly identified from the sur-gical teams' hands in the present report were Staphylococ-cusspp., Bacillus spp., Micrococcus spp., and Rothia spp.Staphylococcus was the most commonly identified bacte-rium and that finding is similar to other studies, likelybecause Staphylococcus spp. is part of the human skinmicroflora.9,25The second and third most commonlyidentified bacterial species in the present report wereBacillus spp. and Micrococcus spp. Unlike Staphylococcus ,Bacillus , and Micrococcus are not a normal part of thehuman skin microflora,26but can be environmental con-taminants and have previously been identified as intrao-perative contaminants.27,28The fourth most commonlyTABLE 9 Samples where isolated bacteria from the cuff and hand were identical.SamplesPre-CGE nondominantspeciesPost-CGE nondominantspeciesPre-CGE dominantspeciesPost-CGE dominantspecies Cuff species1 Micrococcus luteusKytococcus sedentariusStaphylococcus spp. Staphylococcus spp.2 Staphylococcus warneri S. warneri S. warneri3 S. warneri S. warneri Rothia amaraeS. warneriS. warneri4 Staphylococcus epidermidis S. epidermidis S. epidermidis S. epidermidisBIEHL ET AL . 753 1532950x, 2023, 5, identified bacterium was Rothia spp., which are found inthe human oropharynx and upper respiratory tract.29Rothia was also found on gloves in a study by Sidhu et al.In that study, the authors suspected that the bacteriacould have been deposited onto gloves or gowns duringconversations preoperatively or intraoperatively. Simi-larly, in the present study, Rothia spp. may have beendeposited on the hands of participants during conversa-tion prior to gloving, after the participant's gloves wereremoved for culturing, or Rothia spp. may have beendeposited onto the culturette or plate during/after theculture was performed. Overall, the bacteria isolatedfrom the surgical teams in the study by Sidhu et al. weresimilar to those isolated from the surgical teams in thepresent study. Interestingly, the most commonly isolatedbacterium in the Sidhu study was Streptococcus spp.,while the most commonly isolated species in the presentstudy was Staphylococcus spp. The difference could beexplained by the fact that in the Sidhu study, theyswabbed the outside of the glove whereas in the presentstudy, we swabbed the hands directly.In four different instances, the same bacteria werecultured on at least one hand pre-CGE and the cuff(Table9). We suspect that this contamination came fromthe hands themselves –again, either hand bacteria con-taminating the cuff prior to or at the time of CGE. Thelack of frequency does not allow statistical association ofthe two events, so further studies are needed.The specific type of surgical procedure was notanalyzed in this study because small numbers ofmany different types of procedures were performed,resulting in insufficient numbers of specific proce-dures for evaluation.There were several limitations to this study. The timebetween regloving and swabbing the hands for the post-CGE sample was brief, averaging 4 min. This provided ashort duration for microbial replication, which mayresult in a low ability to detect bacteria by culture. Ourintent was to identify bacterial contamination thatoccurred at the time of CGE. A prolonged period of newglove wearing would have allowed replication of bacteria,but would have been difficult to differentiate from repli-cation of the bacteria already on the hands pre-CGE. Inclinical practice, most glove exchanges are performedprior to closure and are not worn for a long duration,although it would likely be longer than 4 minutes. Theshort duration during which the gloves were worn couldhave led to a Type II error as the bacteria may have beenpresent but at undetectable levels at the time of sampling.An additional limitation is that bacterial culture usingculturettes has a low sensitivity,30meaning that the num-ber of positive cultures that we recorded may not be accu-rately representative. Further, liquid can increase theresidual kill effect of chlorhexidine gluconate.31Prior toswabbing the hands of the participants, the culturetteswere moistened with approximately 4 drops of sterilesaline; 186 (93%) of the participants did an initial handwash with a chlorhexidine detergent, and so introductionof liquid in the form of sterile saline on the culturetteduring the hand swabbing process could have decreasedthe bacterial load on the hand for the post-CGE. An addi-tional limitation is that the number of positive cultureswas low, which gave us low statistical power, therebyincreasing the chance of a Type II error. Finally, the out-come measured here was bacterial culture, not SSI. Pre-venting SSIs is the primary reason for adhering to aseptictechnique. Future studies would be needed to determineif performing CGE intraoperatively would impact the rateof SSI. Finally, in 16 samples, intraoperative gloveexchange was performed. We do not feel that this wouldimpact the current study as the current study comparedhand contamination at the end of surgery to hand con-tamination following a CGE and did not assess hand con-tamination earlier in the procedure.Clinically, we found no evidence to support disconti-nuing CGE. Further studies regarding rates of surgicalsite infections following different glove-exchange tech-niques would be appropriate.ACKNOWLEDGMENTSAuthor Contributions: Biehl K, BS: Contributed todesign, acquisition, and analysis of data for the work.Rogovskyy AS, MS, DVM, PhD, ACVM: Contributed tothe design, acquisition, and interpretation of data for thework. Jeffery N, BVSc MSc PhD DipECVS DipECVNFRCVS: Contributed to the design, analysis and interpre-tation of data for the work. Douglas P, MSN, RN, CIC:Contributed to design, and acquisition of data for thework. Thieman Mankin KM, DVM, MS, DACVS-SA:Contributed to conception, design, acquisition, and inter-pretation of data for the work.The authors thank the Texas A&M Small Animal Vet-erinary Teaching Hospital faculty, staff, and students forparticipating in this study.CONFLICT OF INTEREST STATEMENTThe authors declare no conflict of interest related to thisreport.

Answer 95

This study demonstrates that lag screws generate a greaterforce of compression and area of compression compared withposition screws in this mature ovine humeral condylar bonefracture model, thereby allowing us to reject the nullhypothesis.At T1, there was no signi ﬁcant difference between thetreatment groups with respect to interfragmentary com-pression and area of compression. At this time point,Table 1 Mean (standard deviation) and p-values for condylar width (mm), medial fragment width (mm), lateral fragment width(mm) and width of the kerf (bone loss) (mm) of cadaveric ovine humeri assigned to the two treatment groupsLag screw Position screw p-ValueCondylar width 39.18 (2.64) 39.18 (2.64) 1.00Medial fragment width 19.00 (1.61) 19.27 (1.35) 0.257Lateral fragment width 19.18 (1.66) 18.91 (1.70) 0.257Width of the kerf (bone loss) 1.00 (0.00) 1.00 (0.00) 1.00Fig. 4 Photograph taken during insertion of a cortical screw insertedas a position screw after anatomical reduction using fragmentforceps. Note the pressure sensitive ﬁlm present in the interfrag-mentary interface and real-time torque measurement machine..compressive load was applied through the fragment forcepsalone, so the lack of a signi ﬁcant difference is not unexpected.At T2, the measured compressive force was generatedthrough a combination of fragment forceps and a corticalscrew. A signi ﬁcant difference was detected between thetreatment groups with respect to both interfragmentarycompression and area of compression, with cortical lagscrews providing greater interfragmentary compressionand area of compression. It is interesting to note thatwhen a screw was inserted using either technique, inter-fragmentary compression increased in magnitude comparedwith T1. In theory, cortical position screws should maintainﬁxation between two fragments without generating inter-fragmentary compression, whereas cortical lag screw ﬁxa-tion should generate interfragmentary compression. It ishypothesized that both screw insertion techniques generateinterfragmentary compression as an initial axial force as wellas a rotational force are applied when driving the screw intothe bone. This may be particularly relevant when self-tap-ping screws are used, as an axial load is vital to cleanly insertscrews of this design. This was appreciable in real time on thepressure-time graph generated by pressure mapping sensorsin the interfragmentary interface, with the pressure slightlydecreasing then increasing as the screw transitioned fromthe near to the far fragment. Clinically, the magnitude ofadditional compression (beyond that of the forceps) achievedwhen a positional screw is inserted may be variable betweensurgeons and related to insertional technique. In this study, asingle surgeon (LF) inserted all implants, making a compari-son between surgeons beyond the scope of this study.The interfragmentary compression and area of compres-sion at T3 reduced in magnitude when compared with T2 butremained greater in magnitude when compared with T1. AtT3, a signi ﬁcant difference remained between the treatmentFig. 5 Mean, standard deviation and p-values for interfragmentarycompression generated by lag screws and position screws at threetime points for ﬁxation of simulated lateral humeral condylar frac-tures./C3Indicates a statistically signi ﬁcant difference between the twotreatments.Table 3 Mean (standard deviation) and p-values for area of compression (cm2) generated by cortical lag screws and corticalposition screws at three time points for ﬁxation of simulated lateral humeral condylar fracturesLag screw Position screw p-ValueTime point 1 0.35 (0.22) 0.31 (0.20) 0.197Time point 2 1.30 (0.58)a0.86 (0.42)a0.008aTime point 3 1.15 (0.48)a0.74 (0.40)a0.006aaIndicates a statistically signi ﬁcant difference between the two treatments.Fig. 6 Mean, standard deviation and p-values for area of compressiongenerated by lag screws and position screws at three time points forﬁxation of simulated lateral humeral condylar fractures./C3Indicates astatistically signi ﬁcant difference between the two treatments.Table 2 Mean (standard deviation) and p-values for interfragmentary compression (kPa) generated by cortical lag screws andcortical position screws at three time points for ﬁxation of simulated lateral humeral condylar fracturesLag screw Position screw p-ValueTime point 1 495.09 (411.49) 481.36 (465.64) 0.722Time point 2 2622.73 (2423.49)a1599.64 (1495.35)a0.003aTime point 3 2043.18 (2085.60)a1326.64 (1301.41)a0.033aaIndicates a statistically signi ﬁcant difference between the two treatments..groups with respect to both interfragmentary compressionand area of compression, with cortical lag screws providinggreater interfragmentary compression and area of compres-sion. The clinical signi ﬁcance of this fact remains unknown atpresent, but we would suggest that greater interfragmentarycompression and area of compression would be desirable forrepair stability and hence fracture healing. As T3 represents asingle time point, future studies would be required toevaluate if this compression is maintained after cyclic load-ing of the limb.Factors that may have contributed to the magnitude ofinterfragmentary compression in both treatments increasingbetween T1 and T2 and then decreasing between T2 and T3include the Kirschner wire and the pressuring mapping sensorﬁlm. The Kirschner wire would have to bend slightly to permitinterfragmentary compression during screw insertion, there-by resisting the advancement of the screw.17Similarly, thepressure sensitive ﬁlm was compressed and acted as addition-al resistance to interfragmentary compression. Once the frag-ment forceps were removed, the Kirschner wire and pressure-sensitive ﬁlm would produce a force opposing interfragmen-tary compression. Clinically, the Kirschner wire may act toreduce interfragmentary compression in a similar fashion toour study if inserted in the same order but in addition, theloading of the limb may produce additional forces acting todistract the intercondylar fracture.Ultimately, T3 represents the most relevant clinical timepoint. At this time point, cortical lag screws were found togenerate a signi ﬁcantly greater interfragmentary compres-sion and area of compression compares to cortical positionscrews. We suspect that is the result of more even applicationof the compressive load as it is generated from the centrallylocated screw head and not from the screw threads as wouldbe the case in a positional screw.Several studies have quanti ﬁed and compared the bio-mechanical properties associated with lag screws and posi-tion screws. A biomechanical study using simulatedsemicylindrical porcine rib fracture models demonstratedthat preloaded position screws yield greater interfragmen-tary compression compared with lag screws.18Anotherbiomechanical study using simulated intraarticular verticalfemoral fracture models established that lag screws generategreater interfragmentary compressive force than positionscrews, a contradiction of the previous result.19Differencesin experimental equipment and methodology may accountfor the differences in results. A biomechanical study in whichoblique osteotomies were created in composite cortical bonemodels found that lag screws signi ﬁcantly increase inter-fragmentary compression generated by fragment forceps,whereas position screws not only fail to maintain but signif-icantly decrease the interfragmentary compression.20There are several limitations to the clinical extrapolationof the results of this study to a clinical population of caninecondylar fractures. The mineral density of bone is likely toinﬂuence the magnitude of compression that can be pro-duced and maintained using a transcondylar screw and itmust be recognized that the density of canine bone maydiffer to that of ovine bone, and age-related or pathologicaldifferences in bone density (as may be seen in cases ofincomplete ossi ﬁcation of the humeral condyle) will limitthe application of these ﬁndings to the clinical scenario.Furthermore, screw insertion torque was recorded using aninstrumented screwdriver, and insertional force was indi-rectly measured at the interfragmentary interface. However,other forces such as the axial pressure applied throughoutscrew insertion, which may be of interest, were not mea-sured. Additionally, it would be desirable to determinewhether a relationship between screw size and condylarsize in ﬂuences interfragmentary compression.It is also interesting to note the large standard deviation inthese samples, which likely indicate variability betweenspecimens. In general, it was noted that the specimenswith higher magnitudes of compression for one techniquealso had a higher compression for the other technique andsimilarly, other samples produced lower magnitudes ofcompression for both tested conditions.Although the present study provides valuable informa-tion regarding the biomechanical properties of lag screwsand position screws in the static-state ﬁxation of matureovine humeral bone fragments, an absence of informationrelated to the biomechanical properties during dynamicmovement remains. As an example, a study comparingcortical screws inserted as lag screws and headless com-pression screws quanti ﬁed maximum displacement, resid-ual displacement and residual rotation of the fragment atwalk and trot loads, then stressed the constructs to failureto determine stiffness and maximum load.6Such informa-tion would increase the clinical applicability and relevanceof the results, as dynamic testing and associated bio-mechanical data provide insight into the implications ofphysiological limb loading, as occurs when an animalbecomes weight bearing post-surgery.In conclusion, both cortical lag screws and cortical posi-tion screws generate and maintain interfragmentary com-pression in this mature ovine humeral condylar fracturemodel. The increased interfragmentary compression andarea of compression seen when lag screws are used maymake them the preferred option in mature bone; however,this would require clinical investigation to con ﬁrm.

Answer 96

The results of the present study demonstrated significantdifferences in odds of mortality in dogs treated forBOAS using conventional incisional, CO 2laser, andBVSD partial staphylectomy techniques. Specifically,BVSD appeared to have overall higher odds of death inthe immediate postoperative period in comparison toboth of the other techniques. We therefore reject ourhypothesis that there would be no significant differencesbetween the techniques evaluated.This data represents the largest study of dogs surgicallytreated for BOAS, specifically English bulldogs, Frenchbulldogs, and pugs. The overall in-hospital mortality inthis study was 4.0%, which is consistent with previousstudies, ranging from 0% to 10%.1–3,8,9,11 –14,21,24,28,29Tem-porary tracheostomy was performed in 5.0% of cases,which is also consistent with previous studies, with reportsof this complication ranging from 0 to 11%.8,9,11 –14,21,24,29In the present study, no significant differences weredetected when comparing conventional incisional toCO2laser partial staphylectomy techniques, which isconsistent with previous studies. In one prospective ran-domized controlled study, no difference in the develop-ment of complications nor ultimate clinical outcomeswere detected in dogs undergoing staphylectomy forBOAS with incisional or CO2laser techniques. Whilehistopathology of the soft palate revealed higher damagescores for the CO 2laser group at day 0, no differenceswere detected at days 3, 7, and 14.18Another retrospec-tive study evaluating risk factors for temporary tracheos-tomy following corrective surgery for BOAS in 122 dogsalso demonstrated no statistical difference betweenthese two techniques.13While CO 2laser may confer thebenefits of shorter surgery times and improved hemosta-sis compared to conventional incisional staphylectomy,no clear differences in clinical outcome have yet beendemonstrated.Use of BVSD technique was found to have signifi-cantly higher odds of mortality prior to discharge com-pared to CO2laser. These findings are in contrast withtwo prior studies comparing these two techniques. In oneprospective randomized controlled study of normalresearch dogs, no difference in clinical outcomes nor his-topathology of the palate at 48 and 96 h postoperativelywas detected, with an average depth of maximal thermalinjury ranging from 3.3 to 5.3 mm.19In another retro-spective study, no significant differences in procedure oranesthesia times, length of hospitalization, and occur-rence of complications were detected between the tech-niques.24The reasons for the disparities in mortalityobserved in the current study may be related to theamount of thermal and direct tissue injury generated bythe BVSD, with resultant pharyngeal edema contributingto postoperative complications. These devices apply bothpressure and bipolar energy to tissues and provide hemo-stasis by coagulation and denaturation of proteins. Whilethe manufacturer website for the LigaSure device cites anaverage thermal depth of injury of less than 2 mm,30clin-ical studies show variation of this value depending on thepower settings used, the specific tissue type, and numberof cycles deployed.31–34In a case series of 22 brachyce-phalic dogs undergoing staphylectomy and tonsillectomyfor BOAS using BVSD, histopathology of the excised ton-sils revealed a mean depth of tissue damage of 3.4 mmfor the lower power setting compared to 10.0 mm for thehigher power setting.32Thermal injury was also found tobe increased with repeated partial tissue bites with inade-quate cooling time of the BVSD in an ex vivo porcinemuscle model.33The BVSD power settings used in theTABLE 3 Results of multivariateanalysis and resultant p-values.Independent variable Odds ratio (95% CI) p-valueSurvival to discharge CO 2laser technique 0.9 (0.2 –4.3) .890BVSD technique* 6.0 (1.3 –28.4) .023Laryngeal collapse* 4.6 (1.8 –11.8) .002Note: Variables with statistical significance are denoted with an asterisk. The referent for technique isconventional incisional staphylectomy.Abbreviations: BVSD, bipolar vessel sealing device; CI, confidence interval; CO2, carbon dioxide.JONES and KENNEDY 127 1532950x, 2024, 1, current study were not noted in the medical records;therefore, the effect of this variable on the outcome ofour cases cannot be determined.Re-sterilization of BVSD handpieces is a standardpractice in each of the hospitals included in this study.This practice is supported by numerous studies, whichdemonstrate adequate performance of the handpiecesafter multiple reuses and resterilization cycles; however,these same studies also demonstrate an ultimate declinein their effectiveness, and the recommendation for smal-ler handpieces, such as the LigaSure Precise used in thisstudy, are to discard following nine uses.35,36An increasein tissue adherence has also been demonstrated with suc-cessive repeated uses of BVSD, which can lead toincreased tissue manipulation and trauma as well asaffect the quality of the seal generated.36The number oftimes an individual BVSD handpiece was used prior todeployment in the cases reported in this study was notknown, therefore the effect of this variable on the devel-opment of postoperative complications could not bedetermined.Thermal injury is also generated by CO2laser, whichvaries based on the settings used. In this study, the spe-cific laser settings were not recorded nor standardizedbetween the hospitals and surgeons, precluding any eval-uation of these effects on clinical outcome. One theoreticadvantage of CO2laser over BVSD is that it does notrequire direct contact with the tissues, which may avoiddamage secondary to compressive pressure and tissueadherence. However, as postoperative laryngeal examina-tion findings and histopathological data were not evalu-ated, drawing any definitive conclusions regarding thetissue effects of each technique investigated is beyondthe scope of this study.Another notable limitation of this study is the lack ofstandardized laryngeal examination findings at the timeof surgery. Specifically, precise grading of laryngeal col-lapse was not always performed. When present, laryngealcollapse was either defined as eversion of thelaryngeal saccules (stage I) or greater (stage II or III).Due to this lack of information, more nuanced effects oflaryngeal collapse based on severity could not be delin-eated. In this study, higher grade laryngeal collapse wasindependently associated with mortality. Higher stagelaryngeal collapse represents an irreversible weakeningof the cartilages of the larynx, and while multilevel upperairway surgery may aid in reducing high inspiratory pres-sures and alleviate some clinical signs, it is perhaps notsurprising that affected animals are more prone to post-operative complications. However, previous studies asses-sing risk factors for dogs undergoing surgical correctionof BOAS have mixed results in regard to laryngeal col-lapse, with one study demonstrating this comorbidity asa risk factor for postoperative complications,37whileothers found no association.13,28Similarly, evaluation ofother potential anatomical upper airway abnormalities,such as aberrant nasal turbinates and nasopharyngealcollapse, was not performed routinely for the dogs of thecurrent study; therefore, these variables and their effectson outcome cannot be determined.Further limitations of this study are largely inherentto its retrospective and multicenter nature. Anestheticprotocols, perioperative medications, surgical techniques,and postoperative treatments were not standardizedamong the 13 individual attending surgeons or five hospi-tals represented in the data. Furthermore, the techniqueused in any individual case was determined solely by sur-geon preference, which did not vary based on any otherpatient variable. In other words, the partial staphylect-omy technique used was 100% correlated with the sur-geon performing the procedure and therefore notassigned randomly, which has the potential to confoundthe outcome measures. Not all surgeons have the sameskill level, and this would likely affect mortality. Whilethe low number of deaths in our study precluded theinclusion of each individual surgeon as a categorical fac-tor in our statistical analysis, we did include the experi-ence level of the surgeon –ACVS diplomate orsupervised resident –as a factor, which did not demon-strate statistical significance in our model.Evaluation of other anatomical upper airway abnor-malities, such as aberrant nasal turbinates and nasopha-ryngeal collapse, was also not performed routinely;therefore, these variables and their effects on outcomecould not be determined. Additionally, this study onlylooked at the effects of these techniques when used toshorten the soft palate. Soft palate thickness may be aneven more important contributing factor in the clinicalcourse of BOAS15; however, as advanced imaging tech-niques were often not performed on the animals reportedin this study, the effect of soft palate thickness on sur-vival cannot be determined. Future studies investigatingthe outcome of more novel techniques which also addresssoft palate thickness compared to these more traditionalpartial staphylectomy techniques are warranted.This represents the largest study to date of brachyce-phalic dogs undergoing surgical correction of BOAS andis also the first study to demonstrate differences in clini-cal outcomes in dogs undergoing partial staphylectomyusing conventional incisional, CO2laser, and BVSD tech-niques. Additionally, higher grade laryngeal collapse wasalso independently associated with mortality. While theuse of BVSD was associated with a higher risk of mortal-ity in this study, clinical studies using a randomized trialdesign should be conducted to further determine theputative influence of surgical instrumentation in the128 JONES and KENNEDY 1532950x, 2024, 1, perioperative mortality rate following multilevel surgeryin dogs with BOAS in order to control for confoundingvariables.AUTHOR CONTRIBUTIONSJones SA, DVM: Completed medical record review, dataaccumulation, and writing of the article; Kennedy SC,DVM, MS, DACVS: Provided guidance for objectives,hypothesis, and revisions.ACKNOWLEDGMENTSThe authors would like to acknowledge JoeG. Hauptman, DVM, MS, DACVS, for his contribution inthe statistical analysis, and Sherrill Sahlin for her assis-tance in procuring the medical records for this report.CONFLICT OF INTEREST STATEMENTThe authors declare no conflicts of interest related to thisreport.ORCIDSarah A. Joneshttps://orcid.org/0000-0003-4938-743X

Answer 97

The Norberg angle shows signi ﬁcant differences with posi-tional variations. The effect is most obvious in the dorso-ventral radiographic projection. This may be due to highermagni ﬁcation of the acetabular rim compared to the mag-niﬁcation of the femoral head. In our setting, the source toimager distance was ﬁxed at 115 cm, and a previous studyshowed elevation of 1 cm from the imager results in mag-niﬁcation of 1% of the true size.21Our results are in contrastto a study where no difference was found between ven-trodorsal and dorsoventral positioning.22As described inthe other study, dorsoventral positioning can be recognizedby a more proximal superimposition of the patella over thefemur compared to the position of the patella in ventro-dorsal projections. In human medicine, a study describedthe use of the distance between the upper border of thesymphysis and the sacrococcygeal joint as a measure toevaluate pelvic tilt.23Such a measure could may also beused to differentiate between dorsoventral and ventrodor-sal projections.In laterally tilted radiographs (rotation of the pelvisaround the long axis), the value of the Norberg angle changeson both sides, increasing on one side and decreasing to asimilar extent on the contralateral side. As a rotation ofgreater than 2 degrees can subjectively be perceived as tiltedand signi ﬁcant bilateral change of the Norberg angle isdetected starting from /C213 degrees, the risk of misinterpreta-tion of the Norberg angle is low if radiographs are rejected forevaluation. If nevertheless evaluation of the Norberg angle isto be performed in a radiograph tilted more than 2 degreeslaterally, the average of the Norberg angles should be con-sidered for evaluation. Our results suggest the values of theNorberg angle of either side could balance out each other inlaterally tilted radiographs with otherwise symmetrical hipjoints. However, this has not been proven individually andshould therefore not be used in a clinical setting and furtherresearch is needed to evaluate the usability of the averageNorberg angle value.In cranially or caudally tilted radiographs (rotation of thepelvis around the short axis), images are visually perceivedby the observer as obviously tilted if rotation exceeds10 degrees in either direction. Within this range, there isno relevant change of the Norberg angle. This is consistentwith a recent study that found no signi ﬁcant effect of pelvictilt on the Norberg angle in a bone model.11There was noevidence of changes of the Norberg angle of up to 10 degreesas reported previously.10Possibly such a large deviation canonly be achieved by combined rotation and tilting in differentdirections and should therefore be easily perceived as une-valuable. In our study, there was only unilateral signi ﬁcantchange of the Norberg angle for cranioventral to caudodorsalprojections. The unilateral characteristic might be explainedby imperfect positioning in the lateral direction. However,statistical power is limited due to the low number of speci-mens in this study.We could observe a difference in the mean Norberg angleof the right and left sides with higher values for the right hipjoint. This was previously observed in another study andexplained by the lower force applied to the right hindlimbduring radiography in case of right handedness of theexaminer.24In contrast to ventrodorsal radiographs, in dor-soventral radiographs the mean Norberg angle was higher onthe left. This could support our theory of handedness as acause, because the operator grabs the right hindlimb with hisright hand in dorsoventral positioning. Interestingly, thisFig. 6 Effect of rotation of the projection in the transverse plane on the mean Norberg angle (third set). Percentage values describe the variationcompared to the normal positioned radiograph. Signi ﬁc a n tv a l u e sa r em a r k e dw i t ha na s t e r i s ks y m b o l(/C3)..difference was also observed in radiographs where thepatient was positioned using foam pads, sandbags, andtape (second and third sets). In these radiographs, themean Norberg angle of the right side was still higher com-pared to the mean Norberg angle of the left side. Therefore,we assume this effect might also apply in countries such asthe United Kingdom where manual holding of the patient isnot advised and positioning devices are used.The results of the study are limited due to the small numberof cases and the heterogenicity of breeds included. A majorityofdogsshowed some evidence ofdysplasia,probablya resultofusing older dogs in which osteoarthritis commonly occurs. Thepresence of osteophytes at the cranial acetabular edge canpotentially complicate the exact measurement of the Norbergangle. Tilting of the patient wassimulated by rotating theX-raytube as this enabled precise adjustment of the angle of rotationof the X-ray tube in steps of 1 degree. This avoided movementof the patient and therefore joint positions were alwaysidentical. A recent study evaluated symmetry of the caninepelvic radiographs using a special device to rotate caninecadavers ﬁxed to the device using bone pins. Using this device,it was possible to obtain radiographs in four different projec-tions of 0, 2, 4, and 6 degrees.19A dedicated tiltable positioningdevice enables precise rotation presets, but causes elevation ofthe dog from the detector with magni ﬁcation error. Thedisadvantage of this method was geometric distortion dueto unequal magni ﬁcation of the image. This effect is caused byrotation of the tube with constant position of the detector.25This effect increases with increasing X-ray tube rotation angle,but the dimension of the effect was not evaluated and webelieve it is only a small, negligible error compared to methodswith strictly perpendicular X-ray beam projection but poten-tial changes in patient position.ConclusionTilted images that are subjectively perceived evaluable havevery little effect on the Norberg angle and are thereforeprobably acceptable. In laterally tilted radiographs withotherwise symmetrical hip joints, the Norberg angle valuesof the two sides seem to balance out each other. However,this does not justify the use of the average Norberg angle forevaluation. Subjectively perceived tilted images, especiallyalong the short axis of the pelvis, are unsuitable for measureof the Norberg angle. Based on our results, dorsoventralprojections, which can be recognized based on the proximalposition of the patella, should be excluded from evaluation,as the Norberg angle value can be falsely increased.

Answer 98

The goal of this descriptive case series was to evaluate the long-term clinical outcomes associat -ed with the C-THA implant in dogs. Twenty C-THA procedures were performed in 17 dogs. Overall, a good to excellent outcome was noted in 17 of 20 implants (85%). A good outcome was given to a patient who required revision surgery of the im -plant or conversion to a traditional THA. The need for revision surgery was still graded as good to show the versatility of the C-THA implant system as it allows for ease of conversion to a traditional THA system if needed.2All 5 complications occurred in the first 10 cases of this current study. In a study by Hayes et al18 it was noted that proficiency was achieved after per -forming 44 total hip arthroplasty procedures with a cemented system. Although the primary surgeon had performed at least this number of THA’s prior to undertaking a new implant prosthesis, a total num -ber of 44 cases was never achieved with the C-THA. As the primary surgeon’s experience progressed; the incidence of complications decreased. A future study to help determine the number of procedures required to achieve proficiency with this procedure specifically would be advantageous.Rashmir-Raven et al25 reported a strong re -lationship between mean, middle, and distal per -centages of canal fill and the force required for implant subsidence in the cadaveric specimens. Their study’s results supported the hypothesis that implants with a higher percentage of canal fill are less likely to subside than implants with a lower percentage of canal fill.25 As the lateral potion of C-THA stem exits the lateral cortical femur in the region of the third trochanter, it is never reliant on the inner cortices to prevent subsidence. A recent study to evaluate the biomechanical advantages of THA procedures by Ordway et al29 showed that with a short stem design, ultimate failures occurred at 6 to 7 times of a normal simulated gait load. In addition, the C-THA showed significantly greater compressive stiffness and less displacement at peak load in comparison to the lateral bolt, collar -less and collared THA systems.Historic complication rates for THA are underre -ported due to the short to medium-term times fol -low-up associated with most studies. Complication rates with traditional cementless and short-stem designs range from 5% to > 30% depending on the study.2,12–21 This cohort revealed a similar complica -tion rate to other short-stem design that range from 27% to 39%.12,19 A study by Denny et al12 showed a 20% rate of aseptic loosening of the implant, which was thought to be secondary to a lack of osteointe -gration onto the implant. The C-THA is designed to Unauthenticated | Downloaded 10/08/23 06:32 AM UTC6 help prevent stress shielding of the proximal calcar region by allowing for small amounts of micromo -tion at the lateral cortex (Figure 6) . If correctly per -formed the C-THA should only extend 5 mm beyond the lateral cortex of the femur. This lateral opening counters any bending moments associated with the C-THA stem and was not shown to be associated with any pain, impaired mobility or seroma forma -tion within this case series.Septic loosening is a known complication relat -ed to any procedure that involves placement of im -plants.10,14,15,20 This is considered a severe complication with a poor prognosis, as all implants that develop sep -tic loosening will likely require explantation. Duration of surgical procedure length of over 90 minutes has previ -ously been described as a risk factor for septic loosen -ing.34 Duration of surgical procedures were not evalu -ated in our study, but the 2 cases that developed septic loosening were both dogs that had undergone second -ary revision surgeries following luxations. Guthrie et al35 reported that antibiotic impregnated beads placed in a single-stage revision of a known septic loosening resulted in a good outcome 5 years post-operatively. As a result, considering placement of antibiotic beads for prolonged procedures or during revision surgeries may help to decrease the amount of septic loosening noted in future procedures.As reported by Skurla et al,36 aseptic loosen -ing of cemented THAs was documented in 63.2% of dogs on post-mortem exam. Previously published studies report a rate of aseptic loosening from 0% to 11%.2,10,37 Aseptic loosening is thought by some to be the most common long-term complication of cemented-THA.38 Within our study, this occurred to 2 of 20 (10%) of the THAs in this study. This may be secondary to the extended follow-up as both oc -curred 302 or more days after implantation. In hu -mans, it has been reported that infections related to THA contain a variety of colony variants and conven -tional culture techniques frequently do not detect the specific causative organism, therefore infected implants may have been missed.38One limitation of the study is its retrospective nature. The retrospective design introduced a lack of uniformity in timing of follow-up orthopedic and ra -diographic examinations. Most outcomes were sub -jective in nature and were not standardized given the retrospective nature of this study. More traditional measurements such as Liverpool Osteoarthritis in Dogs (LOAD) and The Canine Brief Pain Inventory (CBPI) were unavailable for the majority of patients. Future studies may benefit from objective measure -ments such as force plate analysis. Furthermore, there was no standard control to determine owner compliance and activity restrictions following patient discharge from hospital. In addition, there was no guarantee of owners returning for reevaluation when complications did occur and as a result, complica -tions and poor outcomes may have been missed. The design of the C-THA is unable to correct for inherent femoral anteversion and therefore could have contrib -uted to the 2 hip luxations in our series. Finally, the surgeon was not blinded when performing follow-up lameness and radiographic evaluations, which could have allowed for potential bias in outcome measures.In conclusion, the C-THA provides a novel im -plant system for management of coxofemoral pain and osteoarthritis in dogs. The findings of this study support our assumption that no femoral body frac -tures or subsidence would be identified within this short case series. The short stem design of the im -plants and preservation of the femoral neck allow for conversion to traditional THA systems if complica -tions do occur post-operatively. This study showed that the Centerline Total Hip Arthroplasty (C-THA) system had an overall excellent success rate of 75% (15 out of 20). A complication rate of 25% (5/20) is within previously reported rates of traditional THA systems which range between 5% and >30%.2,10–15,26–28 However, it is significantly higher than more recent reported outcomes in a large case series of cement -ed, cementless and hybrid systems.39 All complica -tions occurred within the first 10 procedure in this short case series. An increase in surgeon experience with this novel implant system should help to reduce technical surgical errors resulting in better outcomes and consequently reduced rate of complications.AcknowledgmentsThe authors declare no conflicts of interest.We would like to thank Biomedtrix for donating implants for 12 cases, as well as for the design of the implant, provid -ing images used in Figures 1, 5, and 6, and guidance through -out the study period.

Answer 99

Our findings confirm the association between c.1024G> T missense mutation and the folded ears phenotype, whereas the other two mutations (namely c.963A >C and c.1104C >T) detected in exon 6 are silent and not associ -ated with fold phenotype.7Previous studies suggested that SFOCD in heterozy-gous animals has a milder and slower development in comparison with homozygous animals.3 Other studies Table 2 Cat genotypes for the three mutations in TRPV4 exon 6: c.963A>C, c.1024G>T and c.1104C>TCat ID Ear phenotypec.963A>C c.1024G>T c.1104C>TCat_01 Straight CC GG CCCat_02 Straight CC GG CTCat_03 Fold AC GT CTCat_04 Fold AA GT TTCat_05 Fold AC GT TTCat_06 Fold AA GT TTCat_07 Fold AC GT CTCat_08 Straight AC GG TTCat_09 Straight AC GG CTCat_10 Straight AC GG TTCat_11 Fold AA GT TTCat_12 Fold AC GT CTCat_13 Fold AA GT TTCat_14 Fold AC GT TTCat_15 Fold AC GT TTCat_16 Fold AC GT TTCat_17 Fold AC GT TTFigure 1 Radiographic images of the alterations observed in Cat_17: (a) limbs and paws (right and left side in upper and lower images, respectively); (b) lateral and ventral view of the column, hips and tail4 Journal of Feline Medicine and Surgery reported cases of lesions radiographically evident start -ing from 17 months of age.12 This variance in the mani -festations and severity of clinical signs is justified by the incomplete dominant pattern of inheritance of the dis-ease5 and could explain why, in the first radiographical examination, only one (ie, Cat_17, aged 6.5 years at radio-graphic examination) of the Fold sampled population showed clinical signs of the disease. The radiographical follow-up 1.5 years later showed no progression of the bone changes. This result is consistent with the scenario of a milder and slower development of SFOCD in heterozygous cats.Additional unknown factors are supposed to exert an effect on skeletal phenotypes and could explain the observed variability. Among them, age is a risk factor. With SFOCD being a progressive disorder, changes could be very subtle in cats aged younger than 1 year. On the other hand, regardless of breed, 61% of cats aged older than 6 years demonstrate osteoarthritis in at least one joint.13 Further studies will be required to expand the knowledge on these other factors affecting the develop -ment of SFOCD.ConclusionsSFOCD is a disorder influenced by various factors, including genetic ones. Furthermore, this variance is also found in the manifestation and severity of clinical signs, which is justified by the incomplete dominant pat -tern of inheritance of the disease. Although the effects of the c.1024G> T substitution have been investigated, the progression of this disorder in heterozygous cats is still partly unknown. In this study, heterozygous cats showed minor to no clinical signs of SFOCD, and after a 1.5-year follow-up, no progression of bone changes was observed. Further studies will be needed to evaluate the develop -ment of SFOCD, in order to assess risks and other causa -tive effects.Acknowledgements Thanks to the two cat breeders, Vin-cenzo Pagliarello (‘Dei reali’ cattery) and Taisia Sevets (‘Agorà Artemide’ cattery), for providing the animals for this study.

Answer 100

Our results provide evidence that TPLO combined with anextra-articular lateral augmentation is more effective inreestablishing the native kinematics than TPLO alone, inagreement with our first hypothesis. We found that appli-cation of a rotational moment combined with compressionto stifles treated with TPLO elicited 6-times larger tibialsubluxation compared to cranial cruciate ligament intactstifles. This result suggests that activities with high rota-tional moments may increase the risk of persistent instabil-ity in dogs with complete CCL tear treated with TPLOwithout extra-articular lateral augmentation. This risk maybe higher in stifles with insu fficient rotational restrain,such as stifles with an acute complete CCL tear presentingwith hyperlaxity. The addition of an extra-articular lateralaugmentation significantly improved the kinematics byproviding a static restrain against internal tibial rotation.Consequently, cranial tibial translation elicited by TPT wasfour times lower after combined TPLO and extra-articularlateral augmentation compared to TPLO alone. As rotationand translation are coupled motion in the stifle, increasedrotational restrain is also improving craniocaudal stability.We found that the extra-articular lateral augmentationdid not over-constrain the stifle. After TPLO, internalrotational instability was significantly increased, confirm-ing the findings of Shimada et al.24After application ofthe extra-articular lateral augmentation, the internal rota-tion decreased to the level of the intact stifle, but no exter-nal rotational was noted. Contrary to our results, previousstudies investigating the biomechanical effect of lateralsuture techniques for CCLD treatment have reportedan increase in external rotation after tightening the con-struct.25–27The difference might be explained by using anisometric point for the anchorage of the suture.15The useof a bone anchor allows the surgeon to choose the femoralfixation point compared to other popular techniques suchas the circumfabellar suture.Cranial translation afte r TPLO exceeded 5 mm in 3/10of stifles while performing TCT. This laxity increased whenthe TPT was performed, as all stifles subluxated more than7 mm. Although a direct comparison between ex vivo andTABLE 3 Change in stifle flexion angle during testinga(degree), results of one-way ANOVA, and post hoc testing (if indicated).Test Intact (1) CCLD (2) TPLO (3) TPLO-IB (4) ANOVA post hocTCT (a) 2.46 (0.1) 8.06 (3.79) 2.66 (1.54) 2.75 (1.01) p< .001 *p1–p2=0.005 *p1–p3=1p1–p4=1p2-p3=0.004 *p2–p4=0.002 *p3–p4=1eTPT (b) 5.47 (1.62) 8.08 (4.2) 7.62 (3.41) 4.85 (2.32) p=.081iTPT (c) 2.28 (0.85) 5.8 (2.32) 6.88 (3.42) 3.483 (1.66) p=.002*p1-p2=0.013 *p1-p3=0.014 *p1-p4=0.55p2-p3=1p2-p4=0.028 *p3-p4=0.18ANOVA post hoc p> .0001 p=.11 p< .001 * p=.066pa-pb < 0.001 pa-pb =na pa-pb =0.002 * pa-pb=napa-pc=1 pa-pc =na pa-pc =0.009 * pa-pc=napb-pc=0.0004 pb-pc =na pb-pc =1 pb-pc =naAbbreviations: CCLD, cranial cruciate ligament deficient stifle; eTPT, external tibial pivot compression test, iTPT, internal tibial pivot compr ession test; TCT,tibia compression test; TPLO, tibial plateau leveling osteotomy; TPLO-IB, tibial plateau leveling osteotomy combined with extra-articular later al augmentation.aShown as means (standard deviation).*Statistically significant result ( p> .05).692 HUSI ET AL . 1532950x, 2023, 5, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.13955 by Vetagro Sup Aef, Wiley Online Library on [22/07/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensein vivo studies is difficult, our results from TCT agree withprevious clinical studies reporting a prevalence of 30% ofcases with residual subluxation after TPLO when walkingin a straight line on a linear treadmill.3,4The high incidenceof subluxation with TPT, detected in all stifles after TPLOmay be multifactorial. First, the high degree of laxity maydepend on the lack of periarticular fibrosis as the stifleselected for testing had no preexisting pathology.For this reason, our model best represents a hyperlaxstifle, typically associated with an acute, complete CCLtear, and not to a stifle with a competent partial orchronic complete rupture. In addition, the setup does notinclude a simulation of the muscle forces, which mightdecrease the degree of subluxation in vivo. Lastly, thereported value of 30% persistent instability is based onin vivo studies performed at walk in a straight line.5Thisvalue may underestimate the laxity of a CCL-deficient sti-fle treated with TPLO undergoing activities with largerotational moments.The TPT has been previously validated for assessmentof craniocaudal and rotational instability in CCD-intactand deficient stifles.11It was developed to test rotationalstability, similarly to the pivot shift test in people. Thepivot shift test is used for decision-making and prognosisin people. High degree pivot shift indicates that the kneemay be at increased risk of failure and less likely toreturn to sports.28These knees, defined as hyperlax, areoperated with a combination of intra- and extra-articularreconstruction.29Similarly, the TPT could be used as anintraoperative test to evaluate rotational stability afterTPLO and determine if an augmentation is needed. Fur-ther work is required to develop a grading scheme similarto pivot shift in people and guidelines for performing lat-eral augmentation. Additionally, in vivo studies areneeded to evaluate if the results of laxity tests are corre-lated with stifle laxity during normal activity.The cranial tibial translation induced by eTPT andiTPT was not different within the study phases, suggest-ing that both tests are comparable. We found that exter-nally rotating the tibia before TCT (eTPT) leads to a morepronounced subluxation, which was easier to notice bythe examiner and could therefore increase the test's sensi-tivity in both CCL-deficient stifle and after TPLO. Thisfinding is similar to that reported in people, where theTABLE 4 Femoral axial forcea(N) registered by the load cell during testing, results of one-way ANOVA, and post hoc testing (ifindicated).Test Intact (1) CCLD (2) TPLO (3) TPLO-IB (4) ANOVA posthocTCT (a) 8.25 (3.67) 5.27 (2.23) 7.96 (3.82) 10.32 (4.97) p=.018*p1-p2=0.563p1-p3=1.000p1-p4=1.000p2-p3=0.623p2-p4=0.017 *p3-p4=1.000eTPT (b) 9.3 (3.50) 7.59 (5.15) 8.72 (2.96) 12.04 (6.33) p=.138iTPT (c) 6.87 (2.48) 2.99 (2.21) 6.43 (3.46) 11.31 (5.14) p< .001 *p1-p2=0.064p1-p3=1.000p1-p4=0.264p2-p3=0.034 *p2-p4=0.006 *p3-p4=0.046 *ANOVA posthoc p=.64 p=.0169 * p=.056 p=.455pa-pb=na pa-pb =0.387 pa-pb =na pa-pb =napa-pc=na pa-pc =0.012 * pa-pc=na pa-pc =napb-pc=na pb-pc =0.037 * pb-pc=na pb-pc =naAbbreviations: CCLD, cranial cruciate ligament deficient stifle; eTPT, external tibia pivot compression test; iTPT, internal tibia pivot compres sion test; TCT,tibia compression test; TPLO, tibial plateau leveling osteotomy; TPLO-IB, tibial plateau leveling osteotomy combined with extra-articular later al augmentation.aShown as means (standard deviation).*Statistically significant result ( p> .05).HUSI ET AL . 693 1532950x, 2023, 5, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.13955 by Vetagro Sup Aef, Wiley Online Library on [22/07/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensepivot shift is increased with external rotation.30An expla-nation may be that external rotation first leads to com-plete reduction of the lateral compartment allowing alonger travel distance of the lateral tibial condyle duringsubluxation. Second, locking the stifle in externalrotation followed by femorotibial compression anduncoupling of rotation puts the stifle in a “loaded state ”and accelerates tibial subluxation. Initial application ofexternal tibial rotation during eTPT seems counterintui-tive but kinematic data showed that release of externalrotation following manual compression of the stifle jointleads to a sudden backlash and ultimately results in a netinternal rotation (Figure3).Regarding kinetic data, we found that femoral axialforces registered by the load cell were generally lower inCCLD stifles. This is conclusive for two reasons. First,transection of the CCL leads to loss of craniocaudal stabil-ity. This, in combination with a caudal tibial slope, willredirect axial forces that occur during tibial compressionin a cranial direction. Second, when the observer noticedtibial subluxation, compression was intuitively released,and peak axial forces applied might be lower in the unsta-ble joint. Overall highest loads were measured in theTPLO-IB group. We account this finding to the observer'sattempt to challenge the lateral suture construct regardingits stability. Underloading the stifle after TPLO-IB wouldhave made interpretation of its effects more difficult.One limitation of the study was using a relativelysmall subset of cadaveric specimens, which influencesthe clinical relevance of the results. The setup did notattempt to reproduce weightbearing conditions but onlysimulated the effect of physical examination tests on thestifle joint in different conditions. For this reason, extrap-olation of the findings to in vivo weightbearing condi-tions should be made carefully. A similar testingsetup simulating a pivot shift has been used for testingknee reconstruction techniques in human cadavers.31Thesetup allowed to control the axial load applied and thejoint angles for consistent testing. An advantage of thistesting fixture is that it can be easily reproduced withoutneeding a material testing machine used in previous stud-ies.1,2Another limitation is that only one experiencedobserver performed the tests. Therefore, this study doesnot allow for commenting on interobserver reliability ofthe tests. However, excellent inter- and intraobserveragreement for TCT and eTPT was demonstrated incadaveric canine stifles with intact and transected CCL.115|CONCLUSIONThe eTPT and iTPT, developed to test both craniocaudaland rotational stability, induced subluxation in cadav-eric CCL-deficient stifles stabilized with TPLO. How-ever, stifle joints appeared stable when testing withTCT. The implantation of an extra-articular lateral aug-mentation in combination with TPLO returned thejoints to normal kinematics. While these results suggestthat a rotational stabilizer may be needed in hyperlaxstifles with acute CCL tear, such as CCL-deficient cadav-eric stifles, any translation to clinical cases should becautious. Based on the study results, both eTPT andiTPT might be useful tests to assess stifle stability afterTPLO and be included in the decision-making processof whether or not additional stabilizing techniquesshould be considered. Knowing that persistent jointinstability accelerates the progression of osteoarthritisand the development of meniscal tears,32,33those find-i n g sc o u l db ec o n s i d e r e dr e l evant. A prospective studyshould assess the implementation of those tests in clini-cal cases and the benefits of additional stabilization withan extra-articular lateral augmentation technique inselected cases with persisten t marked rotatory instabilitytreated with TPLO.FIGURE 3 Exemplary graphsshowing cranial tibial translation androtation curve during eTPT as obtainedafter processing kinematic data.694 HUSI ET AL . 1532950x, 2023, 5, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.13955 by Vetagro Sup Aef, Wiley Online Library on [22/07/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseAUTHOR CONTRIBUTIONSHusi B, med vet, Park BH, PhD, Lampart M, med vet andPozzi A, DECVS, DACVS, DACVSMR, med. Vet: Con-tributed to study design, study execution and drafting ofthe manuscript. Evans R, PhD: contributed to studydesign, statistical analysis and drafting of the manuscript.ACKNOWLEDGMENTSThe authors would like to thank the team of ProfessorDr. med. vet Michael Weishaupt for their support withthe use of their facilities during data collection. We alsogratefully acknowledge Michelle Aimée Oesch from Vet-com for the photographs. Open access funding providedby Universitat Zurich.CONFLICT OF INTEREST STATEMENTProfessor Antonio Pozzi consults and receives royaltiesfrom Arthex Inc, Naples, Florida.ORCIDBrian Parkhttps://orcid.org/0000-0002-3980-0801

Answer 101

In the current study, the success rate of clearing an orthopedic surgical site infection was 77%. Two factors were associated with an increased risk of treatment fail -ure: a higher number of surgical procedures before hy -drogel administration and the presence of multidrug or methicillin resistance. The chance of treatment success decreased by approximately 25% with each additional surgery performed before P407 hydrogel implantation. This can be due to compromise of the biologic envi -ronment (devascularization and fibrosis) resulting from surgery. The importance of preserving vascular supply, soft tissue envelope, periosteum, and endosteum to optimize fracture healing has been emphasized in the scientific literature.28 A recent study29 suggested that a reoperated fracture site had lower periosteal and end -osteal blood flow values compared to a nonoperated limb. Decreased blood flow could negatively impact both bone healing and the delivery of systemically ad -ministered antibiotics to the fracture site. Multiple pro -cedures requiring the insertion of orthopedic implants may also predispose the operated site to an increased risk of introducing additional bacterial contaminants.30The second risk factor associated with treatment failure was the presence of a multidrug- or methicillin-resistant infection. Treatment failure after vancomycin-impregnated P407 hydrogel administration was 7.69 times more likely when a multidrug- or methicillin-resistant organism was present. Several orthopedic SSI studies reported a higher risk of treatment failure in cases with multidrug-resistant infections compared to those infected with antimicrobial-sensitive bacte -ria.31,32 The treatment of multidrug-resistant infections often requires extended systemic antimicrobial therapy and results in increased morbidity, increased number of surgical procedures, greater financial burden, and pro -longed hospitalization.31,32 This is especially difficult in cases infected by virulent strains of biofilm-producing bacteria such as methicillin-resistant S pseudinterme -dius for which monotherapy with systemic antimicrobi -als is often ineffective.33 Treatment of these infections requires a higher minimum concentration of antimi -crobials (minimal biofilm eradication concentration) that are able to penetrate biofilm (such as vancomy -cin); however, residual biofilm can still be observed.33 In humans, the use of local antimicrobials appears to be advantageous by achieving higher concentrations of antimicrobials in the local environment.8 Studies in -cluding a control group of animals are required to elu -cidate whether the use of local antimicrobial delivery increases the likelihood of treatment success for multi -drug-resistant infections.Implant retention following P407 hydrogel im -plantation was significantly associated with failure of SSI clearance in univariable analysis, but it was not included in the final model because it did not meet the set P value after backward stepwise selec -tion. This may have been due to implant retention confounding with other factors, such as increased number of surgeries. It is also possible that debride -ment, lavage, removal of the existing implants, and placement of new implants free of biofilm minimized the risk of persistent infection. A controlled study comparing a population of dogs undergoing implant retention procedures for management of osteomy -elitis is required to specifically evaluate the potential beneficial effects of local antimicrobial therapy.All dogs reported in the current study received van -comycin using P407 hydrogel as a vehicle for local de -livery. It is not a routine practice for vancomycin, a criti -cally important antimicrobial, to be used for therapeutic purposes. Antimicrobial stewardship aims to minimize or eliminate mass administration of important antimicrobials in groups of animals, particularly livestock.34 Widespread administration for purposes such as growth promotion or prophylaxis is a key contributor to antimicrobial resis -tance (AMR).34,35 This is such a concern that use of several antimicrobials for growth promotion was banned in the European Union.36 More recently, antimicrobials, including vancomycin, were deemed critically important to human health and should be reserved for human use.37 There is potential concern for the use of vancomycin in dogs, as this may constitute poor antimicrobial stewardship. How -ever, the contribution of therapeutic antimicrobial use for companion animals to developing AMR in human medi -cine is unclear and therapeutic use in individual animals has not been found to be a risk or contributor to AMR.34,35 While close contact may raise concern for transmission of resistance from dogs to humans, 1 study exploring the transmission of vancomycin-resistant Enterococcus in ca -nines found phylogenetic linkage for AMR between dogs and humans to be limited.38The One Health initiative describes optimal use of antimicrobials in both human and veterinary medicine as therapeutic in purpose, with better control of the types and amounts of antimicrobials in use, and a de -crease in the numbers of resistant bacteria that are al -lowed to be placed into the environment.34 Most dogs described in this report were at an increased risk for treatment failure due to a compromised biologic en -vironment and the presence of a multidrug-resistant infection. A large number of the multidrug-resistant infections the authors’ institution are due to methi -cillin-resistant Staphylococcus or Enterococcus spp with susceptibility limited to vancomycin, amikacin, and rifampin. The alternative to escalated therapy for these animals included continued prolonged systemic therapy accompanied with prolonged morbidity and variable outcomes, or amputation of the affected limb. Systemic antimicrobials have varying success in cases of orthopedic SSI in the presence of an implant, with reported rates at approximately 70%.39 In light of this, a single dose of a local antimicrobial may be an important option to explore to improve standard of care and promote antimicrobial stewardship.Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 07/22/23 07:43 AM UTC JAVMA | AUGUST 2023 | VOL 261 | NO. 8 1191No adverse drug events related to vancomycin- impregnated P407 hydrogel implantation were ob -served. This may support that P407 hydrogel is a safe vehicle for local drug administration in dogs as demon -strated in previous studies.40,41 However, the systemic and local effects of vancomycin concentrations were not investigated. In vitro studies demonstrated that high local antimicrobial concentrations of vancomycin were cytotoxic.42,43 This cytotoxic effect caused by the local administration of vancomycin has not been evaluated in vivo; thus, future studies focused on osteoclastic activity and time to radiographic osteosynthesis following van -comycin-impregnated P407 hydrogel implantation are needed. Nephrotoxicity and increased risk for acute kid -ney injury has been demonstrated in humans as a result of prolonged use and increased doses of vancomycin.44 A pharmacologic study evaluating the systemic absorp -tion of vancomycin after local administration in small animals and its potential toxicity should be considered. Additionally, an FDA-approved vancomycin- or amikacin-impregnated gel for local antimicrobial therapy is not currently available for use in veterinary medicine, and the gels were compounded in the authors’ institution under sterile conditions. Veterinarians should adhere to compounding regulations and be aware that pharmaco -kinetic properties may differ between compounded and FDA-approved products. The current study had limita -tions. A small population of dogs was evaluated over a relatively short period. All dogs were evaluated at least 180 days following initial infection; however, a prospec -tive study at 1 year after conclusion of all therapies in a larger population may yield different results. Owner compliance in administration of systemic antimicrobi -als was unknown, and thus inconsistent dosing that af -fected treatment outcomes is possible. This study did not include a control population of animals treated for orthopedic SSI without local antimicrobials.Lastly, the volume of vancomycin-impregnated P407 hydrogel administered to each surgical site was not standardized. Varying doses between dogs may have resulted in concentrations of vancomycin that were lower than minimum eradication concen -trations and influenced outcomes. A pharmacologic study to develop a standardized dosing to ensure adequate concentrations can be considered.In conclusion, the local administration of vanco -mycin-impregnated P407 hydrogel had a high suc -cess rate with no gross adverse events in this popula -tion of animals. Outcomes were negatively impacted by the presence of multidrug or methicillin resistance and, to a lesser extent, by an increased number of surgeries before gel implantation.AcknowledgmentsThe authors have nothing to declare.

Answer 102

To the authors’ knowledge, this is the first ret -rospective case series comparing perioperative and postoperative complications in a large number of dogs and cats that had an active closed suction subcutaneous drain surgically placed and were ei -ther managed completely in the hospital setting (re -moved prior to discharge, Group ND), or discharged home with drain for ongoing outpatient care (drain in place at time of discharge, Group D).In this study, being discharged home with a subcutaneous drain in place (Group D) significantly increased the odds of experiencing drain-associat -ed complications compared with having a drain re -moved prior to discharge ( P = .001). The majority of reported complications were classified as minor, including drain dislodgement, wound dehiscence, seroma formation, recurrent swelling and wound discharge, difficulty managing drains at home or sur -gical site infection, which either self-resolved with time or were easily managed with antimicrobials and repeat bandaging.The complication types and rates of minor com -plications in this study (29%) are in close agree -ment with a previous veterinary closed suction drain study2 that reported minor complication rates between 33.8% and 35.3%. That particular study2 examined drains managed only in the hospital set -ting, and not managed in the outpatient situation. Therefore, although there was an overall comparable rate of complications, their rate of complications for drains managed in hospital was much greater than this study. The discrepancy could be secondary to strict asepsis and effective management protocol in our hospital. It is also possible that some minor complications in Group ND were underrepresented in our study. The majority of reported drain compli -cations observed in Group D were minor in nature, such as drain dislodgement, difficulty managing the subcutaneous drain at home and discharge around the drain site; therefore, it is possible that less severe complications may not have been recorded by the hospital staff in Group ND experienced in managing subcutaneous drains as they would have been per -ceived as insignificant.No veterinary studies report specific risks as -sociated with subcutaneous drains managed in the outpatient setting as a comparison. The risks of out -patient subcutaneous drain management is signifi -cantly lower in humans, with a minor complication Unauthenticated | Downloaded 10/08/23 06:32 AM UTC JAVMA | OCTOBER 2023 | VOL 261 | NO. 10 1515rate of 5.6% to 9.6% which include seroma formation, local erythema and surgical site infection.19,20 This could be related to a standardized and longer-estab -lished drain management protocol set in place by hu -man hospitals and better compliance with patients managing their own drain versus owners having to manage their pet’s drain where unexpected incidents may occur despite good owner compliance.We also reported similar rates of major compli -cations (n = 5) to previous veterinary studies.2 Ma-jor complications may have been overrepresented in our study. It was challenging to determine if re -ported complications were directly correlated to the presence of the subcutaneous closed suction drain. For example, the dog with reported tumor recur -rence may be related to the type, grade and resected margins of the mass rather than the presence of the drain harboring neoplastic cells leading to contami -nation of the incision site.21 The dogs that developed surgical site dehiscence may have been secondary to tissue necrosis from inciting trauma or surgery, or poor owner compliance in imposing strict exercise restriction, rather than the drain itself.Despite the increased risk of minor complica -tions seen in our study associated with having a sub -cutaneous drain managed in the outpatient setting, benefits were experienced in this group. In this study, we found that animals discharged with subcutane -ous drains in place (Group D) were hospitalized for a significantly shorter duration, compared with animals that had drains removed prior to hospital discharge (Group ND). Although not examined directly in this study, from previous literature,6,22 it can be extrapo -lated that earlier discharge from hospital would be associated with a considerable reduction in the over -all cost of hospitalization. For owners with financial constraints, earlier discharge from hospital may allow them to proceed with the recommended treatment plan without sacrificing the benefits of a subcutane -ous drain. Furthermore, longer hospitalization can increase animal stress and anxiety, and requires ad -ditional hospital personnel and resources.23–25Interestingly, despite the longer median dura -tion of drain placement in Group D (5.6 days vs 3.1 days), there was no association detected between the duration of drain placement and the risk of com -plications. This finding suggests that the increased risk of complications in Group D is more likely the result of outpatient-specific factors or drain man -agement itself and is not associated simply with the risk of longer drain duration. In human medicine, patients with a closed suction drain are discharged with instructions for frequent showering, wash -ing the drain exit site before and after emptying, and recording the volumes drained.19 In veterinary patients, regular cleaning and maintenance of the drain site is more challenging, particularly in the outpatient setting, secondary to increased environ -mental contamination, difficulty keeping the drain site clean, non-trained personnel, and decreased animal compliance. This may have increased the risks of drain site contamination and infection in the outpatient setting.Veterinary patients also carry the added risk of self-trauma. The risk of premature drain dislodge -ment or disruption in the outpatient setting was found to be low (n = 5/77), with only 1 dog requiring replacement of their subcutaneous drain. Fortunate -ly, the majority of animals that dislodged the drain at home either did not have to have it replaced or dis -lodged the drain in its entirety, therefore additional surgical intervention was not warranted. Despite the possible risks of self-trauma to the external drain components, it appeared that good owner compli -ance was achieved in the majority of cases based on the recommended treatment protocol.Longer hospitalization periods have been asso -ciated with an increased risk of acquired nosocomial infections in human and veterinary studies.2,14,15,26,27 However, an increased risk of postoperative infection in animals hospitalized for a longer period was not supported in this study ( P = .254). Group ND was as -sociated with a longer duration of hospitalization ( P = < .0001), but not an increased risk of postoperative infections. In fact, no postoperative infections were reported in this cohort. Furthermore, the rate of pos -itive cultures collected intraoperatively at the time of drain placement was not statistically different be -tween groups ( P = .013), signifying that Group ND was not inherently less contaminated as a group to start. The lack of postoperative infections observed may be associated with a good hospital protocol with aseptic measures to minimize cross-contam -ination between animals and between the hospital environment and the animal.Despite 45% of animals in our study having a positive bacterial culture at the time of surgery, the overall infection rate was low at 2%. This finding is similar to Reiffel et al20 where 63.4% of patients that underwent plastic surgery with an indwelling drain placed had positive bacterial cultures, but overall wound infection rate was low at 5.6%.20 This may be related to appropriate initiation of prophylactic broad-spectrum antimicrobial treatment intra- and postoperatively to reduce risk of wound-associated and nosocomial infections. Human studies have sup -ported the use of prophylactic antimicrobials while subcutaneous drains are in situ.7Interestingly, the degree of surgical site contam -ination did not increase the risk of complications in our study ( P = .427). This was contrary to previous findings Carvalho et al28 found that surgeries classi -fied as clean-contaminated, contaminated and dirty/ infected exhibited an increase of 54%, 167%, and 105% respectively, in terms of chances developing a surgi -cal site infection compared to clean wounds.28,29 This could be due to good owner compliance and a stan -dardized drain management protocol put in place. Further investigation is required to determine the efficacy of our study’s postoperative drain manage -ment protocol in reducing the risk of SSI.There were several limitations of this study, pri -marily attributed to its retrospective nature. A num -ber of animals were lost to follow-up (n = 11 short term and 18 long term). Their respective owners and referring veterinarians were contacted for records Unauthenticated | Downloaded 10/08/23 06:32 AM UTC1516 JAVMA | OCTOBER 2023 | VOL 261 | NO. 10and information could not be retrieved. Some of the lost data may potentially cause a bias in the results obtained, and the number of complications reported may potentially be higher than described.Drain fluid production volumes were not includ -ed due to a lack of data and non-standardized doc -umentation in many patients with outpatient drain management. Although owners were instructed to record the drain volume at least twice a day (or more frequent if the reservoir was full), not all own -ers were compliant and recorded data when present, was frequently incomplete. This made it challenging to trend and quantify drain production throughout a patient’s disease course and at the time of drain re -moval. Such information may have provided valuable insight into increased causes of postoperative risks (ie, seroma formation, infection, wound discharge). For outpatients, owners were instructed to return at 3 to 5 days postoperatively and the decision to pull the drain was dependent on the owner’s subjective interpretation of drain production volumes at home. This may have resulted in some cases of either pre -mature or prolonged drain removal. At home drain production interpretation was likely much more chal -lenging to interpret than in the hospital setting by trained veterinary hospital staff.Not every surgical site was cultured for the pres -ence of microorganisms. The decision to perform culture and sensitivity was dependent on its class of contamination. Dogs and cats with traumatic wounds had culture samples performed due to the level of perceived contamination of the surgical site (ie, Class IV – infected/ dirty), whereas most ani -mals undergoing elective tumor/mass excision did not have cultures performed due to a perceived cleaner surgical classification (ie, Class I). Despite this assumption, there are animals with fast grow -ing tumors which may develop secondary infec -tion of the tumor/surgical site prior to surgery due to self-trauma from irritation or discomfort caused by the tumor. Culture and sensitivity results should have been performed in all patients to reduce bias and to obtain a better representative sample. Some animals were also prescribed antimicrobials prior to the procedure, which may have affected culture and sensitivity results.Last, it is also possible that more complicated wounds were more likely to be managed in hospital than on an outpatient basis. This selection bias may have caused the complication rate reported in Group D to be proportionally much higher than Group ND, and the majority of complications reported in Group ND to be minor.In conclusion, this study found that there was a higher risk of complications discharging an animal home with a subcutaneous active closed suction drain versus removing the drain prior to discharge. These complications, however, are considered mi -nor and are either easily managed medically or do not require additional treatment. The complications associated with discharging an animal home with a drain should still be discussed with the owners prior to discharge. There was no difference between the degree of surgical site contamination and the risk of developing complications associated with SSI. Dura -tion of hospitalization is significantly shorter when animals are discharged with continued drain care at home. The decision to discharge a stable animal home with a drain should ultimately depend on the temperament of the animal, owner compliance in terms of management and return for follow-up, as well as the additional comorbidities of the animal.AcknowledgmentsThe authors declare that there were no conflicts of inter -est. No third-party funding or support was received in con -nection with this study or the writing or publication of the manuscript. We would like to thank Deborah Keys from Kaleidoscope Statistics Veterinary Medical Research Consulting for her help with the statistical analysis in this paper.

Answer 103

To our knowledge, this was the first study that documented the presence of urolithiasis long-term after surgical attenuation of a cEHPSS in dogs, with known postoperative PSS status. This study revealed that dogs with closed cEHPSS that had urolithiasis at the time of surgical attenuation did not have a higher risk to have recurrent urolithiasis compared to dogs that did not have urolithiasis at the time of cEHPSS surgery. In the only dog with a confirmed closed cEHPSS and long-term urolithiasis, small, nonradi -opaque cystoliths were detected at long-term fol -low-up, while the radiopaque nephroliths that were present at the time of cEHPSS diagnosis decreased in size. Also, the nephroliths that were present at the time of surgical attenuation in the other dogs with closed cEHPSS decreased in size or even disap -peared over time. In contrast, half of the dogs that developed MAPSS following surgical attenuation of cEHPSS were diagnosed with uroliths that were either not yet present or in which previous cystoliths had been removed at the time of surgical attenuation of the cEHPSS.At the time of the prospective follow-up visit, ammonium biurate crystals were not detected in any of the dogs. Two of the dogs with MAPSS and long-term urolithiasis had amorphous crystalluria. The presence of amorphous crystals is a nonspecific finding, and although these crystals were not con -sistent with ammonium urate crystals, the presence of ammonium urate uroliths could not be excluded. Hyperammonemia was present in 4 of 6 dogs with MAPSS, and 3 of 4 dogs had uroliths. However, only in 1 dog there was definite proof of ammonium urate urolithiasis. Radiographic examination was per -formed in one of the remaining dogs and revealed radiopaque uroliths. As ammonium urate uroliths are usually radiolucent7 and no crystalluria was present, it was considered unlikely that the uroliths in that particular dog were composed of ammonium urate. No radiographic examination was performed in the third dog with hyperammonemia that also presented with nonobstructive uroliths. Only 1 of 19 dogs with a confirmed closed cEHPSS in our study was diag -nosed with mineral-opaque lithiasis in the kidneys and prostatic urethra and radiolucent cystoliths at the time of the prospective follow-up visit. No crys -talluria was present, and uroliths were not removed to determine the urolith composition.A remarkable finding in dogs with confirmed absence of postoperative portosystemic shunting is that nephroliths detected at the time of cEHPSS at -tenuation were no longer present at the time of the prospective follow-up visit in 3 of 4 dogs. In the fourth dog, the nephroliths decreased in size over time. It should be acknowledged that only a small number of dogs were included and that no information was available regarding the composition of the nephro -liths. Nevertheless, our findings suggest that ammo -nium urate uroliths can dissolve over time following successful surgery. One dog with MAPSS developed cysto- and small nephroliths 1 year after cEHPSS attenuation while receiving a liver-supportive diet. Cystotomy was performed and confirmed ammoni -um urate cystolithiasis. Lactulose and metronidazole treatment were reinstalled, and the diet was adapted in an attempt to prevent recurrence. At the time of the prospective follow-up visit (16 months postcys -totomy), the small nephroliths were no longer seen, either due to dissolution as a result of the medical therapy or due to passage through the ureter and subsequent excretion. At the time of the prospective follow-up visit, 3 other dogs that developed MAPSS after surgical attenuation of cEHPSS presented with nephrolithiasis, while nephroliths were not identified at the time of cEHPSS attenuation. In total, 4 of 6 (67%) dogs that developed MAPSS had urolithiasis long-term after cEHPSS surgery. The development of urolithiasis might be due to the persistent elevat -ed blood ammonia concentrations, although in 3 of those dogs, ammonium urate urolithiasis could only be assumed but not proven due to the impossibility to perform quantitative stone analysis. The goal of Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 08/30/23 11:59 AM UTC JAVMA | SEPTEMBER 2023 | VOL 261 | NO. 9 1343medical treatment for cEHPSS is to decrease blood ammonium concentration, subsequently decreasing the number and severity of clinical signs5 and reduc -ing the formation and excretion of uric acid, which is an essential component for urolith development.3 A liver-supportive diet combined with lactulose is su -perior to a liver-supportive diet alone.12In the current study, a urinary scoring system was used to quantify the number of urinary signs. Uroliths that solely contain ammonium urate typi -cally have a smooth surface, which limits irritation to the bladder mucosa3; consequently, dogs with am -monium urate urolithiasis might be asymptomatic. Up to 67% of dogs with cEHPSS are reported to have urinary complaints.6 In our study, 32% (6/19) of dogs with cEHPSS had 1 or more urinary complaints be -tween cEHPSS surgery and the prospective follow-up visit, but only 5% (1/19) of dogs with closed cEHPSS had urolithiasis. All dogs that developed MAPSS af -ter cEHPSS surgery were reported to have urinary complaints between the cEHPSS attenuation and the prospective follow-up visit, whereas only 67% (4/6) of dogs presented with long-term urolithiasis. Quan -tification of urinary signs helps to determine their ef -fect on the quality of life of affected dogs.The present study clearly revealed that the presence of bladder echoic foci did not mean that crystalluria was present, and neither the presence of bladder echoic foci nor the presence or absence of crystalluria corresponded with the presence of urolithiasis. The type of crystalluria was also not necessarily compatible with the type of urolithiasis present. It has been documented previously that the type of crystals found in urine does not always cor -respond to the type of uroliths and that urolithiasis can occur without concurrent crystalluria.3,13The current study had some limitations. The se -lected study population was relatively small; espe -cially, the number of dogs that developed MAPSS following surgical attenuation of cEHPSS was lim -ited. As only dogs with cEHPSS were included, no statement can be made about dogs that underwent surgery for congenital intrahepatic portosystemic shunts or for dogs that develop MAPSS unrelated to cEHPSS surgery. Nevertheless, based on the re -sults of the current study, it is to be expected that any type of portosystemic shunting increases the risk of development of urolithiasis. Furthermore, the length of the postoperative follow-up periods var -ied considerably (median, 36 months; range, 13 to 103 months); nevertheless, no significant difference was present between groups. Obviously, nephroliths could not be analyzed, and consequently it remained uncertain whether these were composed of ammo -nium urate. Unfortunately, in one of the dogs with postoperative urolithiasis, abdominal radiographs were not performed, whereas radiopacity could have given a hint toward ammonium urate urolithiasis. In addition, the accuracy of detecting ammonium urate urolithiasis using ultrasonography is lower compared to other types of uroliths.14 The sensitivity to detect urolithiasis using ultrasonography is further influ -enced by patient motion, the presence of intestinal gas, and the degree of bladder distention.15 Despite the fact that all ultrasound exams focused on the uri -nary tract with the aim to identify potential uroliths and were performed by a European College of Vet -erinary Diagnostic Imaging diplomate, it cannot be entirely excluded that some small uroliths remained undetected. Although the area of the cEHPSS was visualized in all dogs, shunting through the cEHPSS due to recanalization was difficult to assess due to artifacts caused by metallic devices used for cEHPSS attenuation (ameroid ring constrictor and vascu -lar staples to secure thin film bands). Furthermore, MAPSS can be missed with abdominal ultrasonogra -phy even if it is performed by experienced ultraso -nographers.16 Of another note, the dogs in this study did not receive a standardized medical treatment (including diet), which might have influenced the outcome, especially in dogs with MAPSS. The data on urinary signs in the period from 3 months post -operatively to the prospective follow-up visit was obtained by owner questionnaire. Questionnaires are useful tools to determine the presence of clini -cal signs17–19; however, accurateness of the answers is based on the owners’ memory and observation competence. As the owners of most dogs partici -pated in previous studies, questionnaires about the presence of clinical signs at the time of the cEHPSS diagnosis were already available. Finally, ideally a negative control group would have been added to compare the prevalence of urolithiasis long-term in dogs following cEHPSS to those that never had vas -cular anomalies.In conclusion, in this study, dogs with successful cEHPSS closure seemed no longer prone to develop urolithiasis and associated urinary complaints in con -trast to dogs that developed MAPSS following cEHPSS surgery. Noteworthy, nephroliths (partially) dissolved after successful surgical attenuation of cEHPSS.AcknowledgmentsNo third-party funding or support was received in con -nection with this study or the writing or publication of the manuscript. The authors have nothing to declare.The authors wish to thank all dog owners for participat -ing in the study and all referring veterinarians for their help in providing data of the dogs and thereby enabling this study.

Answer 104

Based on the results of this study, there were no differ-ences in the yield load, maximum load, and displacementbetween ST and W constructs during single-cycle load tofailure testing in canine cadaveric sternums. The ST con-struct was less stiff than the W construct, consistent withthe mechanical properties of polymers versus metals. Thehypothesis that median sternotomies secured with suturetape were mechanically comparable to wire closure inthe dog was partially accepted.Suture tape is less stiff than orthopedic wire at supra-physiological loads, and using the supplied tensioner pro-vided with the suture tape used in this study likelyimproves reproducible compression across the sternot-omy gap, as opposed to manual tensioning of suture.Though tensioning of suture tape using the supplied ten-sioner has not been studied in canine median sternotomyclosures, reproducible compression may contribute topreventing micromotion at the sternotomy or slippage ofsuture during manual knot tying. A previous biomechan-ical study demonstrated that displacement at loads up to400 N and failure did not show any statistical differencebetween polydioxanone and stainless-steel wire.15Theaddition of a third treatment group using suture (such asTABLE 1 Results from biomechanical testing of full-construct median sternotomy repairs.Group Stiffness (N/mm) Yield Load (N) Maximum load (N)Displacement(mm at load, (N))Suture tape(n=6)65 ± 13 506 ± 170 1278 ± 265 0.58 ± 0.09 (75)0.94 ± 0.17 (100)1.31 ± 0.25 (125)1.69 ± 0.31 (150)2.10 ± 0.38 (175)2.49 ± 0.47 (200)2.89 ± 0.54 (225)Wire cerclage(n=5)107 ± 35 626 ± 218 1511 ± 180 0.47 ± 0.15 (75)0.80 ± 0.24 (100)1.10 ± 0.39 (125)1.37 ± 0.39 (150)1.63 ± 0.59 (175)1.90 ± 0.67 (200)2.16 ± 0.76 (225)p .01 .33 .13 .16 –.39Note : The yield load and maximum load reflect failure of the sternum and not implant failure. Means ± SDs.1060 RIVENBURG ET AL . 1532950x, 2023, 7, polydioxanone or nylon) may have been beneficial assuture has similar handling characteristics of suture tapeand has been frequently compared to orthopedic wirecerclage in previous mechanical testing and clinical stud-ies.15,17,21 –23The length and location of a median sternotomy inci-sion in dogs is unique compared to other musculoskeletalprocedural incisions; however, the implications of this inregard to the rate of complications has not been fullyinvestigated. One paper reporting on complications ofthoracic surgery found an increased rate of complicationsin median sternotomies as compared to intercostal thora-cotomy; however, these were more common in cases ofpyothorax, which were generally approached via mediansternotomy.39These complications were primarily associ-ated with the incision and included seroma formation,edema and swelling, discharge, dehiscence, infection,and suture reaction, among others.This study had several limitations. The first was asmall sample size, creating the possibility of a Type IIerror. This means that, with a larger sample size, it is pos-sible that there would be additional differences found inthe biomechanical performance between the suture tapeand the wire. Mechanical testing was also based on amodel of maximum load (such as a cough) instead ofa low load cycling model that would more accuratelymimic regular breathing, which would be more clinicallyrelevant. Coughing is one of the major concerns inhumans with regard to the stability of median sternot-omy closures, and disruptive forces in the sternotomy ofhumans have previously been calculated to be 500 –1200 N.40A simple mathematical model was made toestimate the disruptive forces of canines across a mediansternotomy using human parameters and was calculatedto be no more than 350 N.40This appears to be an overes-timation; however, results from a porcine model report80 N across the median sternotomy site when the phrenicnerve was stimulated to produce a cough.38Furthermore,breathing forces measured in three orthogonal directionswere less than 45 N ( /C2410 lb), whereas dynamic forceswere highest in the lateral direction during coughing andlow in all directions during normal breathing. However,cyclic loading models that mimic breathing as well as amodel to assess the effects of quadruped ambulation andsternal recumbency would be more clinically relevant.Data from the lower load range may therefore be moreclinically relevant as it is similar to normal breathingforces, which should comprise the majority of the activityduring a patient's healing. Given the resulting lateral dis-placement and transverse shear from breathing andcoughing as well as longitudinal shear from skeletalmovement, human biomechanical testing models haveused distraction, longitudinal shear, and transverse shearto challenge various median sternotomy closure tech-niques.41,42Previously published veterinaryFIGURE 3 Whole constructdisplacements of suture tape and wirecerclage from 75 N to 225 N underquasi-static lateral distraction. Mean± SD error bars.FIGURE 4 Orthopedic wire cerclage sternotomy closuredemonstrating xiphoid separation following distraction withoutimplant failure. X =Xiphoid.RIVENBURG ET AL . 1061 1532950x, 2023, 7, biomechanical studies have used distraction models,focusing on single-cycle load to failure for comparativemechanical stability determination.4,13,17The current study was modeled from a previouslyreported methodology. Designing a custom frame to gripthe bone and soft tissues of a curved ribcage adequatelyproved to be challenging. The authors consequently con-structed a flat frame as described in similar biomechani-cal studies.38,41,42Use of a flat frame may havecontributed to construct failure as it adds an additionalstress to the fixation and limits our ability to understandthe initial stiffness of each repair. Despite this, it doesprovide a similar baseline to other studies using flatframes for distraction studies. A curved frame, similar tothat described by Davis et al.,13may have provided themodel with a more realistic distribution of stress withoutflattening of the construct as was experienced with theframe that was used. Fluoroscopic imaging or opticaltracking during cyclic mechanical testing using a curvedframe to allow for assessment of sternal movement andgapping at the osteotomy line is an avenue for futurestudies.An additional consideration regarding use of suturetape is that, when using suture tape, there is bulk associ-ated with the knot; currently the morbidity from the bulkof a suture tape knot versus a wire twist is unknown.Complication rates, implications of location and incisionlength, and suture tape knot bulk all warrant consider-ation in clinical decision making regarding closure tech-nique and are avenues for future clinical studies.Based on the parameters assessed in this study, suturetape had biomechanical performance that was compara-ble with that of wire cerclage. We are not yet able to rec-ommend the use of suture tape over orthopedic wire as aclosure technique for canine median sternotomies butthe data presented support its clinical utility as a closuremethod in clinical cases.AUTHOR CONTRIBUTIONSRivenburg RE, DVM: Substantial contributions to theconception and design of the work, drafting the work,and critically revising the manuscript for important intel-lectual content. Maxwell EA, DVM, MS, DACVS-SA,CVPP: Substantial contributions to the conception anddesign of the work and critically revising the manuscriptfor important intellectual content. Bertran J, DVM, MS,DACVS-SA: Substantial contributions to the conceptionand design of the work and critically revising the manu-script for important intellectual content. De MelloSouza C, DVM, MS, DACVIM (Oncology), DACVS: Sub-stantial contributions to the conception and design of thework and critically revising the manuscript forimportant intellectual content. Smith B, BS: Substantialcontributions to the design of the work, the acquisition,analysis, interpretation of data for the work (includingstatistics), and drafting of the work.ACKNOWLEDGMENTSWe would like to thank O Hauck MS for manuscriptcritique.FUNDING INFORMATIONThere were no funders for this report.CONFLICT OF INTEREST STATEMENTSupport, implants, and biomechanical testing facilitieswere provided by Arthrex, Inc. BS is a paid employee ofArthrex. No other conflicts of interest are declared per-taining to this report.ORCIDElizabeth A. Maxwell https://orcid.org/0000-0002-8201-040XJudithBertran https://orcid.org/0000-0002-5886-208XCarlos H. De Mello Souza https://orcid.org/0000-0003-4771-7829

Answer 105

Using SA as the gold standard,6,26we aimed to evaluatethe accuracy of detecting medial meniscal tears with NATABLE 1 Tear types and detectionin standard arthroscopy (SA) andneedle arthroscopy (NA)Tear type SA (n) NA (n) Correctly characterized on NA (n)Vertical longitudinal 18 17 17Displaced/unstable 17 14 14Nondisplaced/stable 1 3 1Horizontal 1 1 1Vertical flap 1 1 1No tear 6 7 6FIGURE 1 (A) Standardarthroscopy image of a displacedvertical longitudinal medialmeniscal tear (*). (B) Needlearthroscopy image of the tornmeniscus in the same caseFIGURE 2 (A) Standardarthroscopy image of a normalcaudal horn of the medialmeniscus. (B) Needlearthroscopy image of the caudalhorn of the medial meniscus inthe same caseTABLE 2 Visibility score in standard arthroscopy (SA) and needle arthroscopy (NA)RegionMedian (range)SA visibility scoreaMedian (range)NA visibility scoreaP(NA vs SAvisibility score)Medial: caudal horn 3 (2-4) 2 (2-4) P=.0044Medial: cranial horn 4 (3-4) 3 (2-4) P=.0012Lateral: caudal horn 4 (2-4) 3 (1-4) P=.0005Lateral: cranial horn 4 (3-4) 3 (1-4) P=.0005a1: not visible, 2: minority visible, 3: majority visible, 4: completely visible.EVERS ET AL . 823 1532950x, 2023, 6, in medium-large sized dogs with complete CCLR.Although the visibility of the menisci was lower, andprobing of the lateral meniscus was more difficult withNA when compared to SA, we found a high level agree-ment between the 2 arthroscopic modalities: medialmeniscal status was correctly identified by NA in 25/26cases. In addition, meniscal assessment with NA could beperformed in half of the time required for SA, and theeffect of NA on limb use was minimal.Similar to previous reports in humans, we found thatthe diagnostic accuracy of NA for detecting meniscaltears was comparable with SA.11,14Subjectively wedeemed the image resolution and arthroscopy illumina-tion with NA as excellent, and the image quality wasclearly sufficient for meniscal assessment. Medialmeniscal status was incorrect in only 1 of 26 cases, wherea nondisplaced meniscal tear was not detected with NAbut subsequently identified with SA. While it is possiblethat the meniscal tear developed sometime between NAand SA, it is more likely that the tear was present but notobserved under NA because the interval between proce-dures was <5 days. There was no obvious cause of themisdiagnosis with NA in this single case. Meniscal teardiagnosis was based solely on the ability to palpatedirectly or visualize the tear, but other indications ofmeniscal injury were not considered. The absence of ameniscal flounce sign, for instance, was recently found tobe a strong indicator of a medial meniscal tear,27and thissign may have been helpful in cases where the abaxialportion of the caudal horn was neither visible nor acces-sible with the probe.As only 6 dogs in our study had a normal medialmeniscus, the negative predictive value was less than 90%despite only having the single false negative case. This isan important consideration when interpreting ourresults: NA may have the most benefit for dogs with nor-mal menisci, where it could be argued that surgical stifleexploration would not be necessary if the absence ofmeniscal injury could be confirmed preoperatively. Inves-tigations into NA amongst a study population with alarger number of dogs with normal menisci, such as dogswith partial CCLR, may be warranted.The visibility of the menisci with NA was lower thanwith SA. In our study, for any given arthroscope position,the potential field of view was wider with SA as a 30/C14foreoblique arthroscope was used during SA, whereas theNA arthroscope was 0/C14. The SA arthroscopes were alsolarger and connected to high-definition arthroscopy sys-tems resulting in superior image resolution and clarity.Subjectively, we also noted that it was more difficult tomanipulate the NA arthroscope in larger stifles or stifleswith more periarticular thickening, as the NA arthro-scope had a tendency to flex when manipulated. As NAwas mostly performed with sedation rather than generalanesthesia, we were unable to apply larger distractionforces to increase the joint space. Similar limitations werenoted for assessment of fragmented coroniod processes indogs with NA.21Arthroscopic shaving was also permittedwith SA but not available for NA. Nevertheless, we wereable to assess at least part of the caudal medial meniscuswith NA in every case.As probing is an important component of meniscalassessment,6we compared the ability to probe themenisci between NA and SA. There was no difference inprobing score for the medial meniscus but the lateralmeniscus was more difficult to probe with NA whencompared to SA. The reasons for this finding wereunclear but it may have been more difficult to pass amedially positioned probe into the lateral stifle compart-ment with NA because shaving of the infrapatellar fatpad and CCL remnants was not possible. As the primaryobjective of the study focused on assessment of medialmeniscal tears, steps to improve lateral meniscal assess-ment such as switching instrument and scope portalsmay have been overlooked. Cannulas and probes specifi-cally designed for use during NA are available,13but weelected to use a standard small hook probe instead. Thegreater difficulty with probing of the lateral meniscusmay explain why the single lateral meniscal tear was notidentified with NA. This study, however, was notdesigned nor powered to evaluate the utility of NA fordiagnosing lateral meniscal tears.One of our original goals was to determine if NAcould be performed under sedation, as the ability to eval-uate meniscal status in a treatment-room setting is attrac-tive. Ten of 26 dogs had additional chemical restraints,and these dogs were briefly anesthetized with either abolus injection of an induction agent or mask delivery ofisoflurane. Due to logistics in our hospital, the timerequired to obtain radiographs can be prolonged, and NAmay have been possible in more cases without generalanesthesia if the interval between delivery of sedationand NA was shorter. Further, as the protocol forTABLE 3 Probing difficulty scoreRegionMedian(range) SAprobingscoreaMedian(range)NAprobingscoreaP(NA vs SAvisibilityscore)Medial: caudalhorn4 (1-4) 3 (1-4) P=.073Lateral: caudalhorn4 (2-4) 2 (1-4) P=.0017a1: impossible, 2: difficult, 3: moderate, and 4: easy to probe.824 EVERS ET AL . 1532950x, 2023, 6, additional chemical restraint was also not standardized,whether additional sedation (rather than general anes-thesia) would have been sufficient for NA is unknown. In2 prior clinical investigations, the potential benefit of fullanesthesia over sedation was suggested for elbow andshoulder NA in dogs.21,22Needle arthroscopy did not appear to induce clinicallyappreciable morbidity. In t he 14 dogs that underwent NAand SA on separate days, there was no difference in lame-ness scores before and after NA. As the primary rationalefor NA is to minimize tissue trauma, the lack of significantmorbidity was expected. Arthroscopic ports, arthroscopeinstruments, volume of fluid d elivery, and applied distrac-tion were all smaller with NA when compared with SA dur-ing meniscal treatment in human patients.12,13Needle arthroscopy was completed within a meanduration of 8 minutes, which was approximately half thetime required for SA. Although we did not record theduration of each specific component of arthroscopy, webelieve that reduced procedural time with NA wasrelated to the lack of time spent shaving, as well as mini-mal hemorrhage from smaller ports. Surgeons may havealso felt greater urgency to complete NA as fast as possi-ble because it was generally performed under less chemi-cal restraint than SA.Whether NA is justified for detecting medial meniscaltears prior to definitive surgery is debatable. It could beargued that intra-articular assessment by arthotomy orSA is essential for every dog undergoing joint stabiliza-tion for cranial cruciate ligament rupture, for reasonssuch as debriding the remnants of the torn ligament andthoroughly inspecting articular surfaces; conversely,there is also a belief that joint assessment is virtuallynever required.28Based on our results, we contend thatNA may be useful for surgeons who believe joint inspec-tion is necessary solely for identifying and treatingmeniscal tears, and managing a dog that is suspected tohave normal menisci –eg, based on lack of chronicity,low level of pain and lameness, and absence of meniscalclick.5,29Limitations of the study include subjective quantifica-tion of meniscal visibility and probing, which may be sus-ceptible to both intraobserver and interobservervariability. Similarly, NA proficiency may vary betweensurgeons, including the 2 surgeons participating in thisstudy; our study design precluded the ability to discernany potential intersurgeon variability in the accuracy ofmeniscal assessment using NA. Both surgeons in thisstudy were proficient with SA, and we suspect NA wouldbe challenging for surgeons who do not have much stiflearthroscopy experience. Our study population was specif-ically limited to medium-sized dogs with complete CCLRinjury prior to surgical stabilization, and the results maynot be applicable to other clinical scenarios such asassessment for postoperative meniscal injury, isolatedmeniscal injury, and in stifles with partial CCLR.In summary, NA was an accurate diagnostic tool fordetecting meniscal tears in dogs with complete CCLRand was associated with minimal morbidity. The optimalutilization of NA within the diagnostic algorithm for dogswith CCLR requires further investigation.ACKNOWLEDGMENTSAuthor Contributions: Evers JS, med. vet.: Drafted themanuscript, collected the data. Kim SE, BVSc, MS,DACVS: Performed surgical procedures, collected thedata, assisted the first author in writing the manuscript.Johnson MD, DVM, MVSc, DACVS: Performed surgicalprocedures, collected the data, and reviewed andapproved the final version. Lazarus MA, DVM: collectedthe data, and reviewed and approved the final version.CONFLICT OF INTERESTThe Nanoscope was provided by Arthrex. SEK is a con-sultant for Arthrex. MDJ has been a prior consultant forArthrex.

Answer 106

This is the first study assessing the use of miniaturelaparoscopic biopsy forceps for liver biopsy in cats. Theresults suggest that the liver biopsies performed usingthe 3 mm miniature laparoscopic biopsy forceps providedsmaller samples than the 5 mm biopsy forceps but con-tained sufficient hepatic lobules and portal triads basedon previously reported guidelines to reach a histopatho-logical diagnosis.Eighty percent of biopsy samples in this study wereassessed as histologically normal and all morphologicdiagnoses were graded as mild and did not require medi-cal treatment. Periportal lipidosis was identified in 9% ofbiopsies, and is defined as the accumulation of lipidwithin the cytoplasm of hepatocytes of the periportalzone.17The cats used in this study were undergoing anutritional study assessing choline and L-carnitine sup-plementation in lean and obese cats. Choline andL-carnitine affect hepatic metabolism –specifically lipidmetabolism –which may have affected fat depositionwithin the hepatocytes, depending on body fat percent-age.18,19The diagnosis of periportal lipidosis in this studywas therefore unsurprising. Reactive portal hepatitis wasdiagnosed in 9% of samples. This can result from expo-sure to various infectious, metabolic, or pharmaceuticalagents, and is often diffusely distributed throughout theliver.17However, identifying a cause can be challengingthrough histologic analysis alone.17Although the morphologic diagnosis from 3 mmsamples obtained using the TP technique provided goodagreement with 5 mm samples, this was not the case forTABLE 2 Median (range) histologic findings for each biopsy technique and forceps size.Histologic artifactTechnique Forceps size Size*techniqueTwist+pull Pull Twist p 3m m 5m m ppCrush artifact (0 –3) 1 (0 –2) 0 (0 –2) 0 (0 –2) Overall .03P-TP .07P-T .41TP-T .010( 0 –2) 0 (0 –2) .67 Overall .093*5 P .953*5 TP .993*5 T .80Fragmentationartifact (0 –3)1( 0 –2) 1 (0 –2) 1 (0 –2) Overall .62P-TP .34P-T .76TP-T .521( 0 –2) 1 (0 –2) .22 Overall .573*5 P .563*5 TP 1.03*5 T .99Abbreviations: P, pull; T, twist; TP, twist +pull.DOBBERSTEIN ET AL . 307 1532950x, 2024, 2, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14049 by Cochrane France, Wiley Online Library on [14/02/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensethe P and T biopsy techniques where poor agreementwas noted. This contrasts with results from a studyperformed by Kimbrell et al.,10which reported good diag-nostic agreement between the 3 and 5 mm forcepssamples in canine cadaver livers, and a study by Buoteet al.,11which reported excellent agreement betweenwedge and 5 mm laparoscopic cup biopsies obtainedusing various biopsy techniques. Care was taken, duringpaired liver biopsy collection, to obtain side-by-sidesamples leaving a few mm between samples to avoid iat-rogenic artifact that could lead to variations in diagnosis,given that the same area could not be biopsied twice. It isstandard practice to obtain three or four samples fromdiffering liver lobes to obtain an overall diagnosis becauselesions may not be evenly distributed throughout theentire liver.16,20In contrast, in this study, single compari-sons between the paired 3 and 5 mm biopsy samples wereused, which may also have limited the agreement in thisstudy compared to what might be seen clinically whenseveral samples are collected and pooled to reach a diag-nosis. Furthermore, a final definitive diagnosis (typicallyobtained using a guillotine or at post mortem) was notavailable in this study. Finally, the TP samples were allobtained from the first biopsy event, which included12 cats and provided one additional paired sample. It ispossible this factor contributed to the agreementobserved for this technique and/or the lack of agreementseen for the other techniques where only 11 pairs wereavailable for analysis.Twenty-five mm2is the reported mean surface area ofwedge liver biopsies in cats in a single study.21Compara-tively, the mean surface area of liver biopsies using 3 mmminiature biopsy forceps in the current study was similarat 20.61 mm2. Thus, obtaining a liver sample using moreinvasive surgical techniques to provide the largest samplemay not be necessary as the 3 mm miniature biopsy for-ceps may provide a similar sample size. In humans, thenumber of portal triads is counted to assess if there issufficient tissue in a sample to make a microscopicdiagnosis.22Reports range from 6 to 11portal triads nec-essary for accurate grading and staging of liver dis-ease.22,23In dogs, Kimbrell et al.10reported that themean number of portal triads obtained using thestandard 5 mm biopsy forceps was 21.4, and 13.8 for3 mm biopsy forceps. In this study, the mean number ofportal triads was larger in the 5mm samples compared tothe 3mm samples ( p< .0001) which was expected consid-ering that the 5 mm biopsy samples will inherently belarger. The mean number of portal triads using 3 mmminiature biopsy forceps was 19, which is notably greaterthan the recommended 6 –11 in humans, and the 13.8reported by Kimbrell et al.,10using the 3 mm miniature cupbiopsy forceps in dogs. Therefore, 3 mm miniature cupbiopsy forceps theoretically yield enough tissue to provide amicroscopic diagnosis, grade, and stage of liver disease.Interestingly, both the T an d the P techniques providedmore portal triads per sample compared to the TP tech-nique ( p=.015 and p=. 0 0 3 .r e s p e c t i v e l y ) .I ti sp o s s i b l ethat T and the P techniques result in larger samples withmore hepatic architecture. However, the T and P techniqueswere performed at different bi opsy events by different sur-g e o n ss oi ti sp o s s i b l et h a tt h er e s u l t sw e r ea f f e c t e db yt h ebiopsy event or the surgeon performing the biopsy.As far as the authors are aware, there is no studycomparing liver biopsy techniques and tissuesample quality in cats. This study found that the TP tech-nique led to greater tissue crush artifact than theT technique alone. This is similar to the results of arecent study that described a twisting technique where90% of samples had sharp edges and 65% of samples hadmild to moderate tearing artifacts.11Although theTP technique resulted in greater tissue crush artifact, themedian crush artifact was mild (grade 1), and a morpho-logical diagnosis was still obtained in all tissue samples,so this finding may not be clinically relevant.When the biopsy technique was ignored, there wasno overall difference in crush and fragmentation gradebetween the 3 and the 5 mm biopsy forceps. Both instru-ments provided a median crush artifact of 0 (none) andfragmentation artifact of 1 (mild), suggesting that bothlaparoscopic instruments are excellent at limiting livertissue sample damage and can be used confidently toobtain clinical samples. In contrast, Fernandez et al.12reported a median crush and fragmentation artifact of 1(mild) using the same grading scheme to assess 5 mmbiopsy samples in canine patients with hepatic disease.TABLE 3 Morphologic diagnoses by forceps size and biopsy event.Biopsy forceps size and eventNodularhyperplasiaReactive portalhepatitisPeriportalglycogenosisPeriportallipidosisNormalliver3 mm first event 0 2 0 1 95 mm first event 0 1 0 1 103 mm second event 1 3 1 1 165 mm second event 0 0 1 3 19308 DOBBERSTEIN ET AL . 1532950x, 2024, 2, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14049 by Cochrane France, Wiley Online Library on [14/02/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseThe grade discrepancy could be related to the sharpnessof the laparoscopic instruments used. The instrumentsused in this study were purchased and used only for thisstudy and a canine clinical liver biopsy study. They werechosen for these studies t o ensure the same cup design(no pin) was used for both sam pling methods. Discrepan-cies could also relate to species differences or to the fact thatthis study included clinically normal colony cats undergo-ing a nutrition study, whereas the Fernandez et al.12studyincluded canine patients undergoing liver biopsies for liverdisease which could affect liver friability.There are several limitations to this study, the mostnoteworthy being that only one sample was collectedwith each technique and biopsy forceps at different timepoints throughout the study. This may have limited ourmorphologic diagnosis agreement data because clinicallyseveral samples from various liver lobes are collected andassessed collectively to reach a diagnosis. This mayexplain our lower agreement compared to a recent studythat examined three samples using each technique andfound excellent agreement for the diagnosis.11Havingthree veterinary surgeons with differing surgical experi-ence perform the liver biopsies may also have influencedthe size and quality of samples obtained. However, liverbiopsies are routinely performed by veterinarians of vary-ing experience, which might lead to some variability withany liver biopsy. Finally, although we performed liverbiopsies in live cats for this study, the lack of actualliver disease in the colony cats used for this study mayhave limited our ability to draw conclusions for a popula-tion of cats with clinical liver disease. Future prospectivestudies looking at the use of the 3 mm miniature biopsyforceps in a clinical population are warranted.The 3 mm biopsy forceps shaft length was sometimesshort in larger cats when used through a left paramedianportal placed slightly cranial to the subumbilical cameraportal. This prevented access to all liver lobes, especiallythose of the right division. Based on this, it may be pru-dent to place the instrument portal more cranially inlarger cats to facilitate access to all liver lobes when using3 mm laparoscopic cup biopsy forceps.In conclusion, liver samples can be safely collectedwith 3 or 5 mm laparoscopic biopsy forceps in cats andprovide sufficient tissue, with minimal artifact for histo-pathology analysis. Based on these results, diagnosticaccuracy of 3 mm samples remains unknown. Given alack of randomization of biopsy technique between sur-geon and biopsy event, and only one sample pair col-lected and compared for each technique, it is challengingto draw solid conclusions regarding the diagnostic accu-racy of each biopsy technique. Additional research inves-tigating biopsy techniques and forceps size is warrantedto confirm the results presented herein. Moreover, forfuture research, samples should be collected at the sametime points, under the same sampling conditions, withclinical cases, in feline patients.AUTHOR CONTRIBUTIONSDobberstein REA, DVM: Performed surgical biopsies,compiled all data, interpreted data, drafted and revisedthe manuscript. Brisson BA, DVM, DVSc, DiplomateACVS: Developed the design of the study, performed sur-gical biopsies, oversaw data collection, interpreted data,drafted and revised the manuscript. Foster RA, DVM,PhD, Diplomate ACVP: Contributed to the design of thestudy, performed the histological analysis of all samplesand revised the manuscript. Monteith G, MS: Contrib-uted to the design of the study, analyzed data for statisti-cal significance and drafted the manuscript. Larose PC,DVM, DVSc: Performed surgical biopsies and revised themanuscript. Rankovic A, MSc, PhD: Contributed to thedesign of the study and revised the manuscript.Verbrugghe A, DVM, PhD, Diplomate ECVCN: Contrib-uted to the design of the study and revised the manu-script. Shoveller AK, BScH, PhD: Contributed to thedesign of the study and revised the manuscript. Allauthors provided a critical review of the manuscript andendorse the final version. All authors are aware of theirrespective contributions and have confidence in theintegrity of all contributions.FUNDING INFORMATIONNo third-party funding or support was received in con-nection with this study or the writing or publication ofthe manuscript.CONFLICT OF INTEREST STATEMENTNo conflicts of interest have been declared.

Answer 107

The bladder cuff NCT technique is feasible in cats andenables complete bypass of the ureter for urinary diversionwith patency up to 90 days. Although longer-term assess-ment of the patency of the NCT track and a better under-standing of the impact of this technique on the ipsilateralkidney function is warranted, this technique may be a via-ble option for surgical management of proximal ureteraltrauma or obstruction when conventional ureteral repairis not feasible or when microsurgical instrumentation orexpertise is not readily available. This technique may alsoprovide an alternative for managing various patient typesincluding cats predisposed to urolithiasis, cats with knownperitoneal contamination from trauma, bite wounds, ordrainage catheters, and cats that are young and otherwisehealthy, in attempt to avoid the long-term complicationssuch as infection, encrustation, or obstruction inherent toureteral stents and SUBs.In contrast, the simple NCT technique was not suc-cessful at producing a patent track between the bladderand renal pelvis after the nephrocystostomy catheter wasremoved and thus cannot be recommended as an optionfor ureteral bypass unless the catheter is maintainedpermanently. The simple NCT technique was based onpresumption that epithelial cells from the bladder mucosaand renal pelvis would migrate along the track maintainedby the catheter creating a permanent epithelial-lined track.This presumption was proven false as the NCT trackobstructed in all three cats days after the catheter wasremoved. However, because the technique was relativelysimple, further investigations using a larger diameternephrocystostomy catheter, maintained for a longer periodof time, may be warranted.4.1 |Intraluminal hemorrhageFor the bladder cuff NCT technique, temporarily clamp-ing the renal vasculature allowed for creation of thenephrostomy track and anastomosis of the bladder to thekidney with minimal hemorrhage at the time. However,upon release of the vascular clamp, bleeding from thenephrostomy track into the lumen of the bladder wasnoticeable. The bleeding was self-limiting and none ofthe cats developed complications from blood loss; how-ever, the bleeding resulted in marked hematuria in allcats immediately after surgery. Additionally, four of ninecats developed urethral obstruction secondary to thepresence of blood clots. Temporary indwelling urethralcatheterization was successful at relieving the obstructionin all four cats, but this increased the level of postopera-tive care necessary and was the likely reason for thedevelopment of UTI.With the bladder cuff NCT technique, the 6 mmbiopsy punch was an obvious source of hemorrhage fromthe kidney parenchyma, but since the vascular clampwas maintained until after the bladder was completelysutured to the kidney, it was difficult to control any hem-orrhage from the nephrostomy track at that time. Apotential solution to this problem may be to modify thetechnique to allow for hemostasis of the track after thevascular clamp is removed and before the bladdermucosa cuff is secured. Additionally, using a smallerdiameter biopsy punch may reduce the degree of hemor-rhage, but the 6 mm punch seemed the optimal size toenable securing of the mucosal cuff into the pelvis whileminimizing the risk of narrowing during healing.4.2 |InfectionThe UTIs that occurred in the four cats that developedurethral obstruction were likely due to the indwellingurethral catheterization and ascending infection. How-ever, two cats that did not undergo urethral catheteriza-tion had positive cultures ( Staph. epidermidis ) at the timeof catheter removal on days 117 and 118. Infection in oneof these cats was suspected to be a skin contaminate andthe other was considered clinically relevant. One of thesecats also had a positive urine culture ( E. coli .) at the timeof necropsy on day 146. The UTIs in the four cats withurethral catheterization resolved with antibiotic therapyafter the nephrocystostomy catheters were removed.However, the presence of the catheter was a potentialnidus that could hinder resolution despite appropriatetherapy. Ideally, the nephrocystostomy catheter would beutilized for as short a period of time as possible to mini-mize the risk of infection, as well as any catheter-relatedstranguria or hematuria. The duration chosen to main-tain the nephrocystostomy catheter in the bladder cuffNCT cats ( /C2460 days) was arbitrary and it is possible thatthe bladder cuff sutures alone would be sufficient tomaintain patency of the NCT. Further investigation as toHARDIE ET AL . 969 1532950x, 2023, 7, whether the nephrocystostomy catheter can be elimi-nated altogether allowing for a single-stage procedure, iswarranted.4.3 |Diagnostic imaging and gross andhistological findingsThe bladder mucosa within the NCT track appearedsmooth and well opposed to the underlying renal cortexand pelvis suggesting that the three sutures used to pullthe bladder mucosa into the renal pelvis were effective atsecuring the mucosa and maintaining position. The exactcause of the reduction in renal size, reduced renal con-trast perfusion, abnormal margination, and histologicalchanges in the bladder cuff NCT kidneys are unknown,but likely due to a combination of factors including warmischemia, UTI, and surgical manipulation of the kidney(mobilization, catheterization, biopsy track creation,parenchymal sutures). Warm ischemic injury to the kid-neys in this study was /C2430 min. This duration of ische-mia in cats has been shown to result in no appreciablehistological changes and thus it seems unlikely that theischemia alone was responsible for the changes.17How-ever, warm ischemia in combination with the injury fromthe other surgical manipulations, particularly potentialvascular compromise from the transparenchymal sutures,may have contributed to the changes. The impact of shortduration warm ischemic periods in diseased kidneys isunknown but may be more significant than what isobserved in healthy kidneys. Strategies to reduce warmischemic injury such as preischemic intravenous manni-tol infusion or local hypothermia could also be consid-ered in future research or clinical cases.For the bladder cuff NCT technique, four sutures werepassed through the renal parenchyma and tied on the cap-sule of the kidney. Three sutures were placed through thecaudal pole (bladder cuff sutures), and one was placedthrough the cranial pole (nephrocystostomy cathetersuture). As the sutures were tightened, an indentation inthe parenchyma was created which likely contributed to theabnormal margination detected on CT. Additionally, thesutures and the biopsy punch may have damaged or attenu-ated blood flow, causing chron ic regional ischemia as seenon histology. Overall, the gross and histological changesseen in the bladder NCT kidneys were not entirely unex-pected based on the nature of the technique and furtherinvestigation would be requir ed to determine the clinicalimpact of the changes. Further refinements to the surgicaltechnique may improve outco mes, such as eliminating thenephrocystostomy catheter and associated suture, reducingor eliminating the ischemic time, minimizing peritoneal dis-section, and reducing suture size.4.4 |Vesico-renal refluxAlthough not specifically assessed in this study, reflux ofurine into the renal pelvis is an inherent consequence ofthis technique with the primary concerns being thepotential increased risk for pyelonephritis from ascendinginfection and/or hydronephrosis due to intermittentlyincreased pressure within the renal pelvis. In many ani-mal and human studies, however, the impact that refluxof sterile urine has on these complications is less thanpreviously expected and vesicoureteral reflux (VUR) maybe a subclinical finding.18In an experimental study indogs, pyelovesicostomy resulted in no significant changein renal function or morphology after 52 weeks in theabsence of UTI.19Similarly, in a study involving a mousemodel with congenital VUR, no evidence of refluxnephropathy was detected in the absence of infection.20In humans undergoing pyelovesicostomy or vesicocali-costomy, chronic reflux has not led to major problemsand the incidence of pyelonephritis is not significantlyhigher in these patients.10–14,21,22In cats, the effect ofchronic reflux of urine from the bladder into the renalpelvis is unknown.4.5 |LimitationsLimitations of this study include the use of normal, healthycats and thus the results may be different in cats with renalpathology. The impact of the NCT procedure on kidneyfunction is unknown since the contralateral kidney was leftin place and able to maintain normal serum creatininelevels. Future studies could include attempts to gain knowl-edge of single kidney function either through single kidneyGFR determination or contralateral nephrectomy. Finally,the endpoint for the study wa sr e l a t i v e l ys h o r t( 9 0 d a y s )and it is unknown whether the NCT track would remainpatent for a longer duration.5|CONCLUSIONThe bladder cuff NCT technique was effective at creatinga patent track between the bladder and the kidney. Thistechnique may provide an alternative option for surgicalmanagement of complex proximal ureteral lesions usingnative tissues. Optimizing hemostasis of the biopsy trackand longer-term evaluation of the bladder cuff NCT onrenal function and histopathology is warranted.AUTHOR CONTRIBUTIONSHardie RJ, DVM, DACVS, DECVS: Conception of tech-nique, experimental design, execution of experiments,970 HARDIE ET AL . 1532950x, 2023, 7, analysis of the data and drafting of the manuscript.Schmiedt CW, DVM, DACVS-SA: Experimental design,execution of experiments, analysis of the data and draft-ing of the manuscript. Gendron KP, DVM, DACVR,DECVDI: Design, acquisition, and interpretation of CTdata, drafting and editing portions of the manuscriptassociated with CT imaging. Rissi D, DVM, MS, PhD,DACVP: Design, evaluation, and interpretation of histo-pathology, drafting and editing portions of the manu-script associated with pathology.CONFLICT OF INTEREST STATEMENTThe authors declare no conflict of interest related to thisreport.

Answer 108

The clinical efficacy of VSD in dogs with C-IVDH has been demonstrated in numerous clinical stud -ies, with recovery rates of 65% to 96%.2,4,5 However, when the slot has been excessively large, postopera -tive complications such as intervertebral dislocation, fractures, and associated recurrence of spinal cord disorders may occur, and concomitant VF is recom -mended.6,7 This study of small dogs with C-IVDH showed high recovery and low recurrence rates for VSD both with and without concomitant VF. Our results showed that recovery and recurrence rates were similar after VSD with and without concomitant VF. Of the 12 dogs with recurrence in the adjacent intervertebral region, half had VSD only, and the other half had VF and VSD. Previous reports sug -gested that ASP can occur with bony fusion in the intervertebral region where the VSD was performed, albeit this was in large dogs with caudal cervical spondylomyelopathy,5,9 which has been confirmed in long-term follow-up studies using MRI.20 Although ASP does not necessarily induce C-IVDH recurrence, most recurrences in small dogs in this study occurred in the adjacent intervertebral region, suggesting that VSD might have a biomechanical effect on the ad -jacent intervertebral region, not only in large dogs but also in small dogs. The risk of C-IVDH recurrence in adjacent intervertebral segments has also been noted in large-breed dogs with C-IVDH that undergo VF. In a report on C-IVDH in large dogs, Bruecker et al found recurrence in adjacent intervertebral seg -ments in 66% of VF cases between 8 and 30 months postoperatively.9 However, this study of C-IVDH in small dogs found no difference in recurrence in ad -jacent intervertebral segments between the VF and nVF groups. This difference in results may suggest that ASP due to VF may be mild in small dogs com -pared with large dogs and may not have a significant effect on recurrence in adjacent intervertebral seg -ments. Therefore, in VSD for small dogs with C-IVDH, when the slot volume is larger than recommended, the use of VF does not appear to increase the risk for recurrent disc herniation in the adjacent interverte -bral space, even with concomitant VF.Our results showed that NCDBs had a signifi -cantly lower recovery rate than CDBs and that CMG of severity G3 and G4 had worse recovery rates than CMG of severity G1. Disc extrusions occur more fre -quently in CDBs, whereas disc protrusions occur in older dogs of both CDBs and NCDBs.13–15 Clinically, CMG in C-IVDH is generally less severe in NCDBs than in CDBs.21,22 However, disc protrusions can in -duce Wallerian degeneration of the spinal cord white matter due to chronic spinal cord compression and permeability disorders. When this occurs, the de -generative effects can persist postoperatively even if spinal cord compression is relieved; thus, there may be poor improvement after surgical treatment.23 In the present study, we did not determine whether the herniated discs arising in NCDBs were disc extrusions or protrusions, but NCDBs that have a predilection for disc protrusions might have a lower postopera -tive recovery rate than do CDBs. With respect to pre -operative CMG severity, our results were similar to those of previous reports, in which higher preopera -tive CMG severity is associated with a poorer postop -erative recovery rate regardless of breed. Our results revealed that increasing age is also a risk factor for C-IVDH recurrence after VSD surgery. Intervertebral disc degeneration progresses with age, and C-IVDH usually results from disc degeneration.13 Although disc degeneration is a common finding in clinically normal dogs,24,25 when changes are observed in the vertebral endplates, the likelihood of disc disease in the adjacent disc increases.26 Therefore, it can be in -ferred that older dogs with C-IVDH are more likely to have disc degeneration in the adjacent intervertebral region and age-related changes in the vertebral end -plates, increasing the risk for C-IVDH to recur. The Pfirrmann score is widely used in human medicine for scoring disc degeneration and is suitable for scoring in dogs.27 We found 12 C-IVDH recurrences in discs adjacent to the treatment area, all of which had Pfir -rmann scores of 3 on the first MRI scan. A score of 3 indicates that the distinction between the nucleus pulposus and fibrous ring is unclear on T2-weighted MRI, but the contour of the intervertebral disc is vis -ible and the intervertebral space is maintained.17,18,27 The degenerative process of the intervertebral disc affects the stability of the intervertebral region. This process can be divided into 3 phases: inflammation, destabilization, and restabilization.28 Therefore, a score of 3 can indicate the most unstable state in the degenerative process, where the function of the disc is maintained before stabilization. Surgical pro -cedures in the adjacent intervertebral region might have mechanical effects in the same area, triggering C-IVDH recurrence. It was also considered that nu -cleus pulposus with Pfirrmann grade 3 degeneration Unauthenticated | Downloaded 10/08/23 06:32 AM UTC1508 JAVMA | OCTOBER 2023 | VOL 261 | NO. 10might be susceptible to the mechanical environment of the adjacent vertebral structure.This study had several limitations. First, as this was a retrospective study of clinical cases, follow-up CT/MRI was performed only in cases with evidence of recurrence of clinical signs and when the owner agreed to surgery. Long-term follow-up and repeat CT/MRI scans are needed to assess the development of C-IVDH after VSD and VF; however, it is an ethical challenge to perform another CT/MRI scan in cases without clinical signs suggestive of recurrence. We also only evaluated the patients’ basic physical infor -mation, CMG severity, affected region, and degree of disc degeneration as factors involved in the recur -rence and recovery of C-IVDH after VSD surgery, without considering the presence of spondylosis deformans or the degree of spinal cord compression in the treated intervertebral region. In addition, the screw diameter varied; the selection criterion was the largest screw size that could be inserted into the vertebral body, but there was no absolute indicator. Additionally, there might have been differences in the amount of PMMA used for VF among the indi -vidual cases. In this study, we used the amount of bone cement that we judged would not cause prob -lems when suturing the cervical longissimus, which might have resulted in differences in the stiffness of the intervertebral region after VF.No differences in recovery or recurrence rates were observed in small dogs with C-IVDH that under -went VSD with or without concomitant VF. Cases of C-IVDH in small dogs are often encountered in which extruded disc material cannot be retrieved within the limited slot range associated with their small verte -bral body size. Our results suggest that slot volume could be increased and VF could be applied in com -bination with VSD to sufficiently remove disc mate -rial in small dogs with C-IVDH without increased risk for adjacent, recurrent C-IVDH.AcknowledgmentsNo third-party funding or support was received in con -nection with this study or the writing or publication of the manuscript. None of the authors of this manuscript has a fi -nancial or personal relationship with people or organizations that could inappropriately influence or bias its contents.We gratefully acknowledge the work of past and present members of YPC Tokyo Animal Orthopedic Surgery Hospital. We also thank BioScience Writers for English-language editing.

Answer 109

Head tilt is one of the most recognisable clinical signs in dogs with vestibular syndrome. Observation of the clinical sign is therefore typically associated with a lesion in the peripheral or central com -ponents of the vestibular system. Nevertheless, abnormal posture of the head and trunk has been previously reported with cervi -cal myelopathies, such as head turn ( rotational torticollis ), body turn ( pleurothotonus ), and head and neck turn ( cervical scoliosis ) (Rusbridge et al. 2019 , Nagendran et al. 2021 , Poad et al. 2021 ). This study highlights that in rare cases head tilt might not imply a neuroanatomical localisation to the vestibular system, but can also be considered as a sign of cervical myelopathy (neurological) or cervical myopathy (non- neurological antalgic posture).Head tilt, as a clinical sign, might be a result of different pathophysiologies in animals. In vestibular disease affecting the brainstem or the peripheral vestibular system, head tilt occurs as a consequence of loss of ipsilateral excitatory input to the exten -sor muscles of the neck resulting in a head tilt towards the side of the lesion when the lesion is in the brainstem, the vestibulo -cochlear nerve or the inner ear (Lorenz et al. 2011 ). When the lesion affects the cerebellum (flocculonodular lobes; caudal cer -ebellar peduncles), head tilt can be a result of loss of the cer -ebellar inhibitory influence of ipsilateral vestibular nuclei of the brainstem, resulting in relative excessive discharge from the ves -tibular nuclei forcing a head tilt towards the opposite side off the lesion. This is also referred to as paradoxical vestibular syndrome (Lorenz et al. 2011 ). Ipsilateral or contralateral head tilt has also been described in forebrain disease affecting the ventrolateral and paramedian thalamus, respectively, and it has been attributed to damage to adjacent midbrain regions involved in vestibular func -tion (Concalves et al. 2011 ).Nevertheless, head tilt – usually in the absence of other ves -tibular signs (nystagmus, positional strabismus and vestibular ataxia) and in the presence of signs of cervical myelopathy (tetra/hemiparesis, generalised proprioceptive ataxia, cervical hyperaes -thesia) has sporadically been reported as a consequence of cervical myelopathy (Harris et al. 2011 , De Lahunta et al. 2021a ) includ -ing Chiari- like malformation and syringomyelia (De Lahunta et al. 2021a ). Specifically, signs of vestibular dysfunction can occur with lesions affecting the spinal nerve, dorsal roots or dor -sal grey matter of the C1- C3 spinal cord segments. Such lesions can result in loss of general proprioceptive afferents from neuro -muscular spindles resulting in abnormal function of the epaxial muscles which maintain the normal orientation of the head and neck (De Lahunta et al. 2021b ). This study identified 15 cases of head tilt secondary to cervical spinal or paraspinal disease over a 21- year period in a busy referral hospital. Although the preva -lence of head tilt in dogs with cervical spinal or paraspinal disease remains unknown, this finding suggests that head tilt should be considered a rare finding in dogs with a neck problem. When an intracranial or extracranial cause for head tilt is not identified, advanced imaging of the neck can be considered.The exact pathophysiological mechanism to explain the devel -opment of head tilt in dogs with cervical spinal or paraspinal disease is currently unknown and should possibly be considered multifactorial. This study describes three different suggested ana -tomical origins to cause head tilt in cervical spinal or paraspinal disease: (1) cranial cervical spinal cord, (2) caudal cervical spinal cord and (3) paraspinal muscles. Specific anatomical structures associated with the cranial cervical spinal cord, such as C1- C3 spinal cord segments, roots and ganglia including the spinocer -ebellar and vestibulospinal pathways, have been suggested to play a role in regulating vestibular input in the spinal cord. This study 17485827, 2024, 1, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jsap.13674 by Vetagro Sup Aef, Wiley Online Library on [19/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseT. Liatis and S. De DeckerJournal of Small Animal Practice • Vol 65 • January 2024 • © 2023 The Authors. Journal of Small Animal Practice published by John Wiley & Sons Ltd on behalf of British Small Animal Veterinary Association.64describes two dogs that only developed a head tilt immediately after a C2 modified hemilaminectomy with rhizotomy for surgi -cal resection of a PNST. This manifestation has been previously observed in experimental animals after resection of these nerve roots or blocking them with local anaesthetics (De Lahunta et al. 2021b ). In rats, the C2 and C3 dorsal roots and ganglia provide afferent projections to vestibular nuclei, and therefore these connections reflect the significant role of proprioceptive neck afferents for the control of head position (Neuhuber & Zenker 1989 ). Temporary vestibular signs have been previously observed in three dogs after resection of extraparenchymal spinal cord tumours at the level of C1- C2 vertebrae presumably from surgical trauma to the spinal cord segments or dorsal roots. These clinical signs resolved in all three dogs within 3 to 5 days (De Lahunta et al. 2021b ). In our study, head tilt resolved in one case shortly after surgery, whilst it remained static in the other case in which a C3 spinal nerve root mass was revealed 2 months after surgery. Why these dogs did not manifest head tilt due to the original pathology before surgery whilst other dogs would do, is not completely understood; however, it could be attributed to a possible anatomical variance. For example, some people and possibly animals may have either a smaller number of rootlets or a complete lack of the dorsal root associated with the first spinal cord segment (De Lahunta et al. 2021b ). Therefore, in some dogs a pathological process at that level can cause head tilt, whilst in others not. One of the cases had post- operative MRI, which revealed a poorly demarcated T2- weighted intramedullary hyperintensity ipsilateral to the head tilt. A possible pathophysio -logic mechanism to explain post- operative head tilt could include postoperative extensive oedema affecting the spinal cord or even expanding up to the brainstem. Alternatively, iatrogenic surgi -cal trauma can potentially be associated with more complete and focal damage compared to the initial pathology which eventually is able to cause a head tilt.T wo dogs in this study, one with C2 and C3 spinal nerve masses and one with a C1- C2 papillary meningioma, manifested head tilt. A C1 spinal cord meningioma has been previously reported to cause equivocal head tilt (De Lahunta et al. 2021a ). A possible disruption of the spinocerebellar pathways from the first two cervical spinal cord segments could potentially explain this clinical sign (De Lahunta et al. 2021a ).One dog with a C2 vertebral malformation and another one with a C2 vertebral fracture were included in this study. A pos -sible disruption of spinocerebellar pathways is suspected in these cases, whilst similar diseases causing head tilt have been previously reported in both dogs and humans. A C2- C3 articular process hypertrophy/malformation with associated vertebral canal steno -sis has been associated with head tilt in a dog (Harris et al. 2011 ). Another dog with C2- C5 multiple vertebral malformations (fusion) manifested cervical torticollis (Fernandes et al. 2019 ). In humans, cervical disc degeneration or facet osteoarthritis, the erroneous proprioceptive input distorts the direct linear interac -tion between neck proprioception and vestibular information, resulting in subjective body orientation and other vestibular signs (Yang et al. 2017 ). Additionally, in dogs dorsal angulation of dens in the vertebral canal decreases the vertebral canal diameter and compresses the spinal cord and possibly the spinocerebellar tract causing associated signs (Loughin & Marino 2016 ).Whilst head tilt in cranial cervical lesions can be caused by involvement of specific anatomical structures, belonging to or carrying information for the vestibular system, head tilt with more caudal cervical lesions is likely to have a different patho -physiological mechanism, not directly related to the vestibular system. Four dogs in this study had lesions caudal to C3. T wo dogs had IVDE (C3- C4 or C4- C5) with associated syringomy -elia starting from C2. It is therefore possible that the observed head tilt in these dogs was associated with the more cranially located syrinx (Mulroy et al. 2019 ). Head tilt has been reported in Cavalier King Charles Spaniels with Chiari- like malformation and syringomyelia. It has been hypothesised that this results from the extension of the syrinx into the superficial dorsal horn con -tralateral to the head tilt (Rusbridge et al. 2018 ). One dog had a C3- C4 IVDE and another had a C4 vertebral mass both without associated syringomyelia. In these dogs, an antalgic – developed in a way to avoid pain – voluntary head tilt cannot be excluded. In one dog with C5- C7 CSM, the head tilt could be either anta -lgic or neurological. Interestingly, reticulospinal pathways in the ventrolateral funiculus with terminations in the C5- C6 and C7- C8 spinal cord segments have been observed and given a role in maintaining posture in rats (Reed et al. 2008 ). Therefore, if not antalgic, head tilt in our case with osseous- associated CSM could be a result of interruption of the reticulospinal tract.Unlike the cranial or caudal spinal cord pathology, head tilt appeared to be a non- neurological clinical sign of cervical para -spinal muscle disease. T wo dogs manifested head tilt with cervical paraspinal myositis which resolved after treatment. In humans, head tilt with or without cervical scoliosis is a clinical sign of cervical paraspinal abscess and it is a result of pain or muscle con -traction. Therefore, its pathophysiological mechanism in those cases is non- neurological in origin (Tomczak & Rosman 2012 , Beasley 2021 ) and it can possibly represent different muscle tone- contraction or/and antalgic posture.Head tilt resolved in seven cases of this study after the caus -ative agent was eliminated ( e.g. tumour removal, treatment of myositis, decompression of IVDE). In two cases, one with C2 vertebral fracture and one with osseous- associated CSM, head tilt remained residual. The reason why the head tilt remained might be either due to permanent damage of the vestibular pathways of the spinal cord in conjunction with lack of reparative surgery, similarly to the commonly seen residual head tilt in brainstem or cerebellar vestibular disease in dogs (Bongartz et al. 2020 ). Nev -ertheless, a residual antalgic head tilt due to persistent neck pain and subsequent muscle contracture cannot be ruled out in those cases.Limitations of this study consist of (1) limited number of cases, (2) lack of photographic evidence of head tilt in most cases, (3) lack of systematic thyroid profile testing in all dogs regard -less of clinical suspicion, (4) lack of follow- up MRI of cases and (5) inconsistent follow- up. In animals, it might be difficult to recognise subtle differences in head position. Due to the retro -spective nature of this study, it was not possible to evaluate if “vestibular head tilt” and “antalgic head tilt in response to cervi - 17485827, 2024, 1, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jsap.13674 by Vetagro Sup Aef, Wiley Online Library on [19/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseHeat tilt in cervical spinal or paraspinal diseaseJournal of Small Animal Practice • Vol 65 • January 2024 • © 2023 The Authors. Journal of Small Animal Practice published by John Wiley & Sons Ltd on behalf of British Small Animal Veterinary Association.65 cal hyperaesthesia” can be differentiated. Further studies are nec -essary to compare the clinical features of these two different types of head tilts and investigate further whether a difference between those exists. Additionally, terminology regarding description of the different head and neck positions is not well established in veterinary literature. Therefore, it can be debated whether the term head tilt should apply in animals without a lesion in the intracranial components of the vestibular system.In conclusion, although vestibular syndrome is the most com -mon cause of head tilt, this study illustrates that head tilt can rarely be a neurological sign of cervical spinal or paraspinal dis -ease. Head tilt in cranial cervical myelopathy usually affecting the C1- C3 dorsal spinal cord segments, spinal nerve roots or ganglia, might be a result of disruption of the vestibular pathways within the spinal cord. Head tilt can also occur in dogs with more caudal cervical lesions, in which it is unclear if this is a result of vestibu -lar pathway disruption or antalgic due to cervical hyperaesthe -sia. At last, head tilt can be a clinical sign of cervical paraspinal myopathy most likely as an antalgic sign. In the absence of intra -cranial or extracranial causes of vestibular dysfunction in a dog with head tilt, considerations should be given to a lesion localised in cervical spinal cord or associated structures.Conflict of interestNone of the authors of this article has a financial or personal relationship with other people or organisations that could inap -propriately influence or bias the content of the paper.Author contributionsTheofanis Liatis: Conceptualization (equal); data curation (equal); formal analysis (equal); investigation (equal); method -ology (equal); project administration (equal); resources (equal); writing – original draft (equal); writing – review and editing (equal). Steven De Decker: Methodology (equal); supervision (equal); validation (equal); writing – review and editing (equal).

Answer 110

Results of this study show no difference between treat-ment success, postoperative rescue opioid consumption,CMPS-SF pain scores, or %BW distin dogs receiving car-profen and single-dose surgical wound infiltration witheither LB or saline placebo, after TPLO. We could notreject our null hypotheses. It is possible that the lack oftreatment effect was due to a type II error, as the actualtreatment effect that we observed for %BW distwas lowerthan our estimated value. Enrolling between 58 andTABLE 3 Success/failure analysisresults, where dogs requiring rescueanalgesia at any postoperativetimepoint (0 –48 h) were defined astreatment failures.LB (n=15) Saline placebo ( n=17) Chi square p-valueSuccess ( n) 13 12 .27Failure ( n)2 5Abbreviation: LB, liposomal bupivacaine.TABLE 4 Mean (standard deviation) for %BW distvalues for dogs receiving LB ( n=15) or saline placebo ( n=17).LB (n=15) Saline placebo ( n=17)Time %BW dist Number of dogs %BW dist Number of dogs p-valuePreoperative baseline 6.7 (4.0) 15 7.5 (4.7) 17 .61Time after extubation (h)4 3.9 (4.0) 13 1.6 (1.8) 12a.0812 2.9 (5.0) 13 1.8 (2.8) 12 .0724 3.3 (3.4) 13 2.4 (3.1) 12 .5048 2.4 (2.5) 11b4.8 (3.7) 12 .37Note: For dogs requiring rescue analgesia, concurrent and subsequent measurements of %BW distwere excluded from statistical analyses.Abbreviations: %BW dist, percent of total bodyweight distributed to the operated leg; LB, liposomal bupivacaine.aData point missing for one dog who was too sedated to stand but did not require rescue analgesia.bData points are missing for two dogs that refused to stand (in favor of sitting) on the weight distribution platform but did not require rescue analgesi a.726 ALDRICH ET AL . 1532950x, 2023, 5, 436 dogs into the study within a reasonable period wouldhave been very challenging.Using 46 and 28 dogs, respectively, two previous clini-cal studies25,27found that dogs administered LB were lesslikely to require rescue analgesia after stifle surgery. Thefirst was a randomized, placebo-controlled, masked pilotstudy of dogs undergoing lateral retinacular suture place-ment with arthrotomy. The percentage of dogs requiringrescue analgesia was significantly lower for dogs receiv-ing LB versus placebo over 0 –24, 0 –48, and 0 –72 h post-operative intervals.25Although the extent of the softtissue approach is similar between TPLO and lateral reti-nacular suture placement, TPLO involves greater surgicaltrauma. It is possible that periosteal and bone marrowpain are not well controlled by LB, especially if it doesnot penetrate deeper than the soft tissues into which it isinjected.A randomized, blinded study27incorporated carpro-fen into its postoperative analgesia protocol for dogs thatreceived either LB or 0.5% bupivacaine surgical site infil-tration for TPLO with arthrotomy. There was an opioid-sparing benefit of LB in the face of background treatmentwith carprofen. Over the 48 h postoperative period, dogsadministered LB at wound closure were less likely toneed rescue analgesia and received a lower amount ofpostoperative opioids.27This opioid-reducing effect wasattributed to the longer duration of effect of LB comparedwith standard bupivacaine. Although this study showed aclinical benefit of LB beyond that achieved by carprofenalone, we cannot directly compare their treatment suc-cess analysis with our own. The decision to provide res-cue analgesia in that study was based on pain scoresusing the CSU-CAPS, rather than the CMPS-SF. Theauthors argued27that CMPS-SF scores can be increasedby signs of anxiety in dogs. It is worth noting that whilethe LB pilot study used the CMPS-SF to identify patientsneeding rescue analgesia, the intervention level wasraised from a suggested 6/24 to 8/24 based on investigatorexperience.25Subjective pain scales are limited in their ability todescribe the magnitude of pain relief provided by thetreatment compared to placebo, but they are regarded asthe current gold standard for evaluating pain in ani-mals.42The original, longer form of the CMPS43has beenshown to have criterion validity, demonstrating sensitiv-ity to acute postoperative pain in dogs in a clinical set-ting.44While the CMPS-SF was derived from the CMPSto be more clinically applicable, it has not undergone cri-terion validation. In this and previous studies, back-ground analgesia has been minimized to improve thesensitivity of the CMPS-SF to treatment effect. Similar tofindings in the previous TPLO study,27pain scores in ourstudy were not different for dogs receiving LB comparedto control at any time point. The background effect of thecarprofen given to the dogs in these studies may haveobscured the ability to detect a clinical benefit of LB. Wecould have eliminated the background analgesic effect ofthe NSAID in the present study, but we considered itclinically valuable to determine whether LB might pro-vide detectable analgesia beyond that of carprofen.Another limitation of the study with respect to pain scor-ing was that we did not statistically test interobserveragreement between the two investigators during the pre-study training period.Objective means of pain assessment failed to demon-strate a difference in outcome for dogs receiving LB inboth the present study as well as a previous TPLOstudy.27In the previous study, mechanical nociceptivethreshold values did not differ between dogs that receivedLB compared with 0.5% bupivacaine. It is possible thatthe treatment effects of LB and standard bupivacainewere truly not different enough to be discriminated bypain scoring or pressure algometry. It is also possible thatindividual variability in responses to algometry45orlearned aversion to the algometer with repeated use27,46contributed to the insensitivity of the instrument to pain.Measurement of %BW distas a means of describinglimb use or presumed limb pain has been described inthe literature. Static bodyweight distribution was firstevaluated using pressure sensitive walkway equipment.In normal dogs, measurements of %BW distwere consis-tent from 1 week to the next, provided handling tech-nique was consistent.29In dogs recovering from total hipreplacement, %BW distto the operated limb increased at3, 6, and 12 months after surgery, although it was notpossible to conclude whether this change was related to adecrease in limb pain over time or simply a change inlimb use. In another study, %BW distwas shown to be assensitive as vertical impulse and peak vertical force forevaluating limb use in dogs before and months after totalhip replacement.31An acute pain model was assessedusing both static and dynamic measurements on a pres-sure sensitive walkway to compare a novel formulationof buprenorphine to placebo for the first 72 h followingstifle arthrotomy.47Regardless of treatment, %BW disttothe affected limb as well as peak vertical force (PVF) andvertical impulse (VI) were significantly decreased at allpostoperative assessments compared to baseline; how-ever, treatment with buprenorphine resulted in greater %BW dist, PVF and VI in the operated limb from 48 to 72 hwhen compared to placebo. It is possible that if dogs inthe present study continued to be assessed for an addi-tional 24 h, we may also have seen a difference in out-come between groups. However, prior studies evaluatingefficacy of LB, found improvement over placebo25orbupivacaine hydrochloride27within the first 48 h, so itALDRICH ET AL . 727 1532950x, 2023, 5, would also be expected to see a difference in efficacyprior to the 48 –72 h period in the present study.More recent research measuring %BW disthas madeuse of a weight distribution platform as an alternative topressure sensitive walkway equipment. Measurement of%BW distusing a weight distribution platform was foundto be accurate compared to a pressure sensitivewalkway,32sensitive to, and specific for, limb lamenessand orthopedic disease,33and repeatable for pairedsame-day or next-day meas urements in dogs with hin-dlimb lameness.44In a prior study, CMPS-SF was mod-erately to strongly correlated to %BW distribution.48Inthat study, the treatment group was noted to scorehigher pain scores than the placebo group, so the corre-lation was the opposite of wh at was expected. We foundno linear correlation between these outcome measuresin the present study. This may be due to the fact that weobserved many dogs to offload the affected limb aftersurgery, and some continued to do so for the remainderof our study. It would be inaccurate to assume that alldogs who offload a limb during stance are equally pain-ful. Stance analysis may therefore be an insensitive mea-sure of pain in animals immediately after TPLO.Another limitation was the relatively infrequent post-operative measurement of %BW dist(4, 12, 24, and 48 h)compared with the frequency of pain scoring (2, 4, 8, 12,20, 24, 32, 40, and 48 h). In this way, we may have missedopportunities for %BW distto describe pain. Finally, insome dogs, we observed a preference for sitting or lyingdown on the weight distribution platform, which wasslightly elevated and softer than the surrounding floor.For these dogs, obtaining valid stance data requiredmany passes over the platform. This brings into questionthe practicality of using this equipment to measure %BW dist. Using a weight distribution platform that is lesstempting to dogs as a place of rest could make data col-lection more efficient.Finally, it is possible that LB may provide analgesicbenefits when combined with other medications not usedin this study. For instance, it is possible that LB may pro-vide benefits if combined with epidural analgesia or with afemoral-sciatic nerve block. However, this supposition can-not be determined without further experimental studies.We conclude that in this population of dogs recoveringfrom TPLO and receiving postoperative carprofen, therewas no difference between overall treatment success, rela-tive rescue analgesia requirement, CMPS-SF pain scores,or %BW distin dogs that received surgical wound infiltra-tion with LB compared with saline placebo.AUTHOR CONTRIBUTIONSAldrich LA, DVM, MS, DA CVS-SA: Study conception,study design, acquisition and collation of raw data,writing and drafting of the work, critical revision andfinal approval of the manuscript, and agreement to beaccountable for all aspects of the work. Upchurch DA,DVM, MS, DACVS-SA: Study design, interpretation ofthe data, critical revision and final approval of the manu-script, and agreement to be accountable for all aspects ofthe work. Roush JK, DVM, MS, DA CVS: Statistical inter-pretation of data, critical revision and final approval ofthe manuscript, and agreement to be accountable for allaspects of the work.ACKNOWLEDGMENTSThe authors thank Iulia Osipova for help in the acquisi-tion and collation of raw data.FUNDING INFORMATIONSupported by an institutional grant from the Departmentof Clinical Sciences, College of Veterinary Medicine,Kansas State University.CONFLICT OF INTEREST STATEMENTThis manuscript represents a portion of a thesis submit-ted by Lauren A. Aldrich to the Kansas State UniversityGraduate Program as partial fulfillment of the require-ments for a Master of Science degree. The authors declareno conflict of interest related to this report.ORCIDDavid A. Upchurch https://orcid.org/0000-0001-7409-3957

Answer 111

The results of this prospective case series con -firm the results from the previous study that LaOVH can be safely performed in stable dogs affected by pyometra with a slight modification of the previously published recommendations by Adamovich-Rippe et al.22 Dogs were included if their maximal uterine diameter was below 2 cm in dogs between 5 and 15 kg and < 3 cm in dogs between 15 and 35 kg and if the uterine diameter was ≤ 4 cm in dogs above 35 kg. Uterine diameters were comparable in both groups. Compared to the previous 4-port, 3-port, and single-port techniques, a 2-port technique was successfully used in this study. But besides the fact that LaOVH can be safely performed in stable dogs with pyome -tra, none of the previous studies evaluated the ben -efits of a laparoscopic approach in terms of surgery time, pain, and recovery. Previously well-described benefits for routine laparoscopic sterilization are de -creased postoperative pain and surgical stress4,5,27 as well as potentially fewer surgical site infections.28All the procedures in this short case series were executed by the same specialized surgeon, with ex -tensive experience in both open and laparoscopic procedures. In addition, the anesthetic protocol was identical, trying to keep all variables as comparable as possible in a clinical setting. While healthy dogs in earlier studies4,5 required less postoperative analge -sia with LaOVH compared to open ovariohysterec -tomy, it was not possible with the current study to demonstrate a significant difference in postoperative pain or need for rescue analgesia in dogs with pyo -metra. This is similar to results from 2 more recent studies,29,30 where the authors also were not able to see a difference in the need for pain medication com -paring open ovariohysterectomy to LaOVH in healthy dogs. Nevertheless, there was need for rescue anal -gesia at 4 time points in the OS group, compared to none in the LaOVH group. Possibly a larger cases se -ries would be able to detect a significant difference between the 2 groups regarding postoperative pain and need for rescue analgesia.As expected, the surgical incision was statisti -cally significant longer in the OS group compared to the LaOVH group. On the other hand, the surgi -cal time was statistically longer in the LaOVH group compared to the OS group. Although a median surgical time of 37 minutes in the LaOVH group is comparatively short, especially in comparison to the previously reported surgical times for LaOVH in pyo -metra with a median of 43, 85, and 107 minutes,22–24 it is still more than 50% of the median surgical time for OS. Time to access the abdomen was significantly longer in the LaOVH group, compared to a standard surgical incision. Furthermore, time for ligation of the uterine body took significantly longer in the LaOVH group compared to the OS group. Regardless, there were no significant differences between groups for other surgical or recovery variables.No intraoperative complications were observed in the OS group. On the other hand, technical dif -ficulties specifically related to the laparoscopy equipment occurred in the LaOVH group. None of those required an emergency conversion to OS. Similarly, more intraoperative complications were reported by Davidson et al27 comparing laparoscop -ic ovariohysterectomy to open ovariohysterectomy in healthy dogs.Previous studies2,28 have suggested a decreased risk for surgical site infections with minimally invasive surgery. One medically treated surgical site infection was observed in the OS group, and none were ob -served in the LaOVH group. Due to the small number of patients in this case series, it is not possible to draw any general conclusions from this finding.CRP is an acute-phase protein synthesized in the liver. In general, CRP has been used as a marker for the severity of inflammation and surgical trauma in several previous studies.31 A previous study32 has shown that CRP is a useful biomarker in differentiating dogs with pyometra from dogs with cystic endometri -al hyperplasia. Furthermore, a study by Krzyzanowski et al33 could demonstrate that CRP was increased in all dogs with pyometra. In contrast to the results from a study34 comparing open prophylactic gastropexy Time from surgery completion to recovery variable (min) LaOVH OS P valueTime to extubation 22 (13–74) 32.5 (17–62) .783Time to stand 116 (55–200) 187.5 (59–455) .537Time to drink 210 (57–255) 369 (110–1,650) .082Time to eat 140 (57–271) 445 (74–1,060) .421See Table 1 for key.Table 3 —Comparison (Mann-Whitney U test) of results for recovery variables for the dogs described in Table 1.Table 4 —Comparison (Mann-Whitney U test) of results for perioperative serum C-reactive protein (CRP) concentra -tion (μg/mL) for the dogs described in Table 1.Timing of CRP measurement LaOVH OS P valuePreoperative 114 (18–300) 60 (10–412) .464Immediately postoperative 90 (19–280) 59 (33–291) .66224 h postoperative 144 (52–197) 169 (72–306) .41048 h postoperative 91 (33–182) 96 (32–263) .792See Table 1 for key.Unauthenticated | Downloaded 02/25/24 04:51 PM UTC6 in dogs to laparoscopic-assisted prophylactic gas -tropexy, it was not possible in the current case series to use CRP as a marker for the severity of surgical trauma. One explanation might be the fact that CRP is already elevated at the beginning of the procedure due to the primary disease, and this overlaps with the surgical trauma, making separate evaluations impos -sible. On the other hand, CRP was not different in a previous study29 comparing open OVH versus LaOVH in healthy dogs.29 Similarly, contradictory results were reached in 2 studies comparing CRP concentrations at the time of presentation in dogs with pyometra. The initial CRP concentration was not associated with a prolonged hospitalization in the study by Jitpean et al,35 whereas in the study by Fransson et al,36 a clear relationship between the severity of systemic inflam -matory response syndrome and prolonged hospital -ization and initial CRP concentration was detected. Unfortunately, in the latter studies, CRP was not mon -itored throughout hospitalization. The results from the present case series suggested that CRP is not an optimal marker for predicting time of hospitalization, since none of the patients had normal CRP at the time of discharge 48 hours after surgery. Furthermore, CRP concentration did not differ significantly between the 2 groups of this study, calling into question the reli -ability of that variable for monitoring the severity of postoperative inflammation and surgical trauma in clinical patients with pyometra.The biggest limitation of this study is the low number of patients. This is owed to the challenge of acquiring cases fitting the inclusion criteria and hav -ing supportive staff available for anesthesia and lapa -roscopy equipment as well as postoperative care. Due to the fact that all patients with pyometra are present -ed as an emergency, it was difficult to free the same specialized surgeon with a busy surgical schedule in a nonteaching hospital in combination with a limited number of staff. This made the acquisition of patients very challenging. In addition, many patients had to be excluded since they were not deemed stable, had free abdominal fluid, or were on concurrent medication due to coexisting disease, which would have made equal comparison of all required variables impossible. A further limitation is the fact that the ovarian ped -icles were ligated in the OS group, instead of sealed and transected with a Caiman VSD. The use of a VSD in both groups would have dramatically increased the costs of the study. Another limitation is the fact that pain scoring was performed by different personnel, which might have influenced the results. This is un -fortunately inevitable in a clinical setting and with an observational period of 48 hours. On the other hand, this did account similarly for both groups and reflects the reality in the best possible way. In addition, none of the observers were blinded to the type of surgery, since they had full access to the journal records at the time patients were hospitalized. A final limitation is that all surgeries were performed by a specialist sur -geon already very experienced in laparoscopic sur -gery. Therefore, the surgical times and complications might actually be higher than reported in this study in less experienced hands.In summary, this prospective study was not able to clearly demonstrate the same benefits for LaOVH in dogs presented with pyometra as previously re -ported in elective sterilization in dogs. Although less patients in the LaOVH group required rescue analge -sia, this was not statistically significant, and surgical time was more than 50% longer. In addition, LaOVH required an assistant, which dramatically increases the costs for that procedure. Furthermore, technical difficulties occurred in the LaOVH group, all specifi -cally related to the equipment. Even though LaOVH is an equally safe and effective procedure for treat -ment of pyometra in dogs, it does not seem to be superior over traditional OS in clinical patients with pyometra at this point. Further studies with a larger caseload including surgeons with different levels of experience are necessary to evaluate the potential benefits of LaOVH in dogs with pyometra.AcknowledgmentsPart of the study was presented at the Veterinary En -doscopy Society Congress in Sorrento, Italy, July 2023.DisclosuresThe authors have nothing to disclose. No AI-assisted technologies were used in the generation of this manuscript.FundingThe authors have nothing to disclose.

Answer 112

Among the reports of GDV occurrence after incisional gastropexy or other gastropexy tech -niques,10–12,16 none document the exact reason for failure, but failure could be attributed to breakage of suture material, knot failure, or tearing of tissue. In 1 case report,10 stretching of the gastropexy site was suggested to be the cause of failure. In the study re -ported here, all failures were caused by gastric tissue tearing instead of suture or knot failure; therefore, one might attribute gastropexy failure to stretching or tearing of tissue rather than suture material break -age. One might argue that the observed difference in failure load between SIG and MIG may be attributed to the 2 additional sutures instead of the engagement of submucosa; however, it has been reported that the number of suture bites does not affect the strength of gastropexy.17 Instead, the increased failure load of MIG is more likely caused by the engagement of sub -mucosa, where more collagen is incorporated than when only serosa and mucosa are engaged.Multiple reports have evaluated biomechanical properties and failure loads of different gastropexy techniques either on sacrificed live animals or ca -davers.18–23 However, no optimal force to failure for gastropexy has been determined. The preadhesion failure load ranges from 20 to 80 N among differ -ent gastropexy techniques, and postadhesion failure load up to 123.61 N has been observed with circum -costal gastropexy. No report of postadhesion failure load of incisional gastropexy is available.Polypropylene was the chosen suture for this study, whereas polydioxanone is another popular su -ture for incisional gastropexy. It is unlikely that the loads to failure would differ between polypropylene and polydioxanone in an acute study like this one, since failures were due to tissue tearing and these 2 sutures are similarly strong.24 However, differences in absorption, reduction in tensile strength, and rela -tive knot security could affect long-term gastropexy strength. A prospective live-animal study would be necessary to determine such differences between polypropylene and polydioxanone. In this present study, we observed that all failures were caused by tearing of tissue instead of suture breakage or knot untying. As a result, no significant difference is ex -pected per acute strength between polypropylene and polydioxanone.Limitations of this study were related to the use of cadaveric tissue. Whether the increased strength of MIG compared to SIG would decrease the gas -tropexy failure rate cannot be concluded from this study. Also, complications of MIG could not be de -termined in this study. For example, in the live ani -mal, penetration of the gastric lumen could facilitate infection into the peritoneum across suture place -ments. A large-scale retrospective or prospective study would be required to compare the outcomes and complications of dogs receiving SIG and MIG. Another limitation was the inability to perform sur -gery and biomechanical testing immediately after collection of samples. Storage at 5 °C overnight may attenuate the biomechanical properties of tis -sue and affect test results. However, all samples were processed under similar conditions (storage time and temperature) to minimize the effect of storage conditions. Furthermore, testing of similarly stored intestinal and esophageal samples have yielded inter -pretable results.25–27 Therefore, the observed differ -ences in failure load and work should be valid. Lastly, this study did not compare the strength of SIG and MIG during healing of the gastropexies. Although biomechanical testing of healing gastropexies would yield more directly applicable results, the sacrifice of animals to do so could not be justified. However, the superior acute strength of MIG suggests that MIG would be more secure than SIG during the healing process. Also, it is possible to make additional full-thickness bites as a part of simple continuous suture. Future study is required to compare such technique with SIG and MIG as performed in this study.In conclusion, failure of acutely performed SIG and MIG occurs due to tearing of gastric tissue, and MIG fails at higher forces than SIG.AcknowledgmentsThe authors have nothing to declare.

Answer 113

The measuring position of femoral trochlear morphologyused in the present study was based on previous CT ﬁndingsand set at the deepest position of the femoral trochlea indogs.23This position is located in the relatively proximal partof the femoral trochlea. In dogs, the patella is known to be incontact with the proximal part of the femoral trochlea.30TheTable 1 Number of dogs and body weight for each age groupAge (y) <11 2 3

Answer 114

Near-infrared cholangiography using ICG is safe and fea-sible in healthy dogs and consistently improved visualiza-tion of the biliary tree in this study. The lower ICG doseprovided better delineation of the biliary tree early afterinjection (0 –2 h), while with the higher dose, ICGremained highly concentrated in the liver tissue andresulted in overall lower target-to-background ratios(Figures5and7). Though both doses provided excellentvisualization of the biliary tree at 3 h post injection(Figures6and8), the lower dose provided better contrastbetween the biliary tree and liver.FIGURE 3 Cystic duct fluorescence intensity at given times after indocyanine green (ICG) injection. The dotted lines represent themean fluorescence intensity of the cystic duct for each group. The 95% confidence limits for each group are represented by the solid lines.6 LAROSE ET AL . 1532950x, 0, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14007by Vetagro Sup Aef, Wiley Online Library on [05/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseIn this study, the cystic artery was consistently visual-ized within 10 s of ICG injection and lasted for 30 s priorto the liver becoming fluorescent. This finding suggeststhat in instances where intraoperative identification ofthe cystic artery or aberrant vasculature is desirable,an additional dose of ICG could be administered thoughthis would obscure BD visualization.7Time to fluores-cence of the hepatic ducts (10 min), CBD and CD (15 –20 min) were consistent with those reported in humanexperimental and clinical studies that range from 8 to20 min following IV injection.25,30Perceived and measured FI have been shown todepend on several factors. Increasing the distance betweenthe tip of the endoscope and the fluorophore from 5 to 14and 5 to 15 cm has been shown to result in a 5 to 30 timesand 50% lower FI, respectively, in two ex vivo studies.19,29Maintaining a perpendicular endoscope angle to the ROIalso leads to higher FI measurements.19,29Although thelatter may not always be possible in a clinical setting orwhen using a 30/C14laparoscope, these factors were con-trolled for in this experimental study setting. Patient-related factors such as the presence of local fat andFIGURE 5 Dog 2 (low dose time 0 h): White (left) and fluorescent light (right) intraoperative images at 50 min post-injectiondemonstrating visualization of the biliary tree/gall bladder with high fluorescence of the liver (low contrast to background ratio).FIGURE 4 Contrast ratios between cystic duct and liver at given times after indocyanine green (ICG) injection. The dotted linesrepresent the mean ratios for each group. The 95% confidence limits for each group are represented by the solid lines.LAROSE ET AL . 7 1532950x, 0, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14007 by Vetagro Sup Aef, Wiley Online Library on [05/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licenseinflammation can also reduce the perceived and measuredFI since tissue depth of penetration of ICG NIR lightreportedly ranges from 5 to 10 mm.7,19,21,27None of thedogs in this study had excess fat or inflammation in thearea of interest. Finally, use of different NIR imaging sys-tems complicates comparison between studies as measuredsignal contrast and images gen erated can differ signifi-cantly.29The Karl Storz imaging system used in this studyis commonly found in clinical practice.When measuring FI, ROIs need to be carefully chosenas subtle differences in signal intensity, light reflectionand scatter can occur within the same ROI and can leadFIGURE 8 Dog 6 (high dose time 3 h): White (left) and fluorescent light (right) intraoperative images at 4.5 h post-injectiondemonstrating visualization of the biliary tree/gall bladder with low liver fluorescence (high contrast to background ratio). *Decreasedresolution due to magnification.FIGURE 7 Dog 5 (high dose time 0 h): White (left) and fluorescent light (right) intraoperative images at 50 min post-injectiondemonstrating visualization of the biliary tree/gall bladder with high fluorescence of the liver (low contrast to background ratio).FIGURE 6 Dog 1 (low dose time 3 h): White (left) and fluorescent light (right) intraoperative images at 4.5 h post-injectiondemonstrating visualization of the biliary tree/gall bladder with low liver fluorescence (high contrast to background ratio).8 LAROSE ET AL . 1532950x, 0, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14007 by Vetagro Sup Aef, Wiley Online Library on [05/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licenseto non-representative measurements.34Such artifactswere carefully excluded when selecting ROIs for FI mea-surements in this study. In a systematic literature reviewexploring software packages and formulas used to calcu-late FI in human LC, OsiriX and Image J (US NationalInstitutes of Health, Bethesda, Maryland) were found toprovide similar results, while Photoshop (Adobe Systems,San Jose, California) results differed significantly preclud-ing comparison.34The CDLR formula used in this studywas shown to correspond well with human visual percep-tion.34This is supported in the current study as surgeonqualitative assessments scores reflected contrast ratiomeasurements with L3 and H3 having highest surveyscores and highest contrast ratios.Only five studies have reported on optimal dose andtime of ICG injection for laparoscopic fluorescence chol-angiography in humans. These studies administered ICGat varied doses (0.02 –0.25 mg/kg and 5 –25 mg) andadministration times (0 –24 h prior to surgery), and usedinconsistent NIR imaging technology, imaging softwareprograms and contrast ratio formulas.7,16,32,35,36Theirreported CD- or CBD-to-liver ratios ranged from <1 to2.3 but when ratios of <1 and >1 were obtained, qualita-tive scores revealed improved visualization of the struc-tures of interest, regardless of the actual measuredcontrast ratio.7,32,36Indocyanine green doses selected forthis study were based on the lower and higher end doserange utilized in human studies which provided good FIand contrast ratios. Longer delays between ICG injectionand NIRF imaging led to less residual hepatic fluores-cence and better contrast ratios.7,27,32In this study, wechose to assess two doses between 0 and 5 h followingICG injection in order to investigate timeframes that arepractical for same-day procedures.While lower BD-to-liver contrast ratios may not beideal, they can still result in improved visualization of thebiliary tree against a nonfluorescent (fat or connective tis-sue) background.7,32Nonetheless, an optimal dose andtiming of administration would lead to high CD fluores-cence with low liver fluorescence or high CDLR. This isespecially true in dogs, where little fat is present at thehilus to provide a low fluorescence background. A moreconservative dose and longer time between administra-tion has generally met the aforementioned goals inhumans.7,16,35Indeed, doses of 10 mg given at 10 –12 h34or 10 mg given at 24 h preoperatively16have reportedlyprovided contrast ratios superior to 2.3, that is, the CBDwas twice as bright as the liver. In our study, the CD was>2 to 4 times as bright as the liver in the L0 and L3groups after 80 min and 180 –300 min, respectively. Addi-tionally, a CDLR nearing 3 was obtained in the H3 groupat 280 min with a slope suggesting that the contrast ratiosmay continue to increase leading to further improvedcontrast beyond 5 h. These higher contrast ratios com-pared to the human studies likely result from species-related differences and rigorously controlled factorsaffecting FI in our study. Humans, notably those with ahigher body mass index, have more fat covering their bili-ary tree and commonly present with cholangitis prior toundergoing NIRFC for LC.19,21Residual fluorescence could only be assessed whenthe second ICG injection was at time 0 h. While residualfluorescence was not noted in dogs of the low dose groupor dogs that had >92 h washout period, minimal residualliver fluorescence of the liver and gall bladder was notedin two high dose group dogs with a shorter washoutperiod (72 h). Residual fluorescence was negligible in theliver hilum and minor in the biliary tree and did notappear to affect measurements and contrast ratios. Resid-ual fluorescence should not be clinically relevant but lon-ger washout periods could be considered for canineresearch as the ICG plasma clearance rates and excretionrates are lower in dogs when compared to humans.37–39Hyperbilirubinemia, hypoalbuminemia, hypotensionand reduced hepatocyte function have been shown to neg-atively impact ICG uptake and clearance in humans.21,37,40Furthermore, inflammation can lead to thickened gallbladder and bile duct walls which could affect FI. Whilegall bladder mucocele and associated gelatinous bile mayhinder diffusion of ICG into the gall bladder, ICG shouldstill diffuse into the CBD and possibly the CD to improvevisualization and reduce conversion and BDI rates as itdid in humans.7,15,18,30,41 –44Optimal dose and timing ofICG administration may be different in dogs with moreadvanced disease, and this remains to be studied.Mild adverse reactions to ICG reportedly occur in0.15% of human patients and include nausea, vomiting,and pruritus, whereas severe reactions occur in 0.003% –0.05% of cases and are usually associated with anaphylac-tic shock.33,45Repeated doses are sometimes given forvascular angiography in humans with recommendationsnot to exceed 5 mg/kg/day.46No safety studies or recom-mended dosages have been described in dogs. In thisstudy, mild transient signs suggestive of nausea devel-oped in the four dogs that received the high dose whileawake. General anesthesia may have masked signs ofnausea in the other dogs as ICG was given intraopera-tively for half of the procedures. It is unknown if a slowinfusion could potentially mitigate clinical signs of nau-sea in awake patients. Although larger safety studies willbe needed to corroborate these findings, ICG IV adminis-tration was considered safe in this population of dogsbased on stability of cardiovascular parameters and lackof histamine release.Limitations associated with this study are inherent toits pilot nature. The sample size is small which limits theLAROSE ET AL . 9 1532950x, 0, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14007 by Vetagro Sup Aef, Wiley Online Library on [05/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensestrength of the results. Due to contamination from hemo-lysis, histamine analysis could not be performed on allplasma samples limiting our conclusions. Additionally,order (first vs. second anesthetic event and drug adminis-tration) and its effects on MAP, HR or histamine levelscould not be investigated due to limited power. However,the selected randomization scheme prevented unequita-ble distribution of the events in any group which mayhave resulted in biased results. Finally, the overall assess-ment of NIRFC was performed in a cohort of healthydogs therefore, the results of this study as well as recom-mendations regarding dose and timing of ICG adminis-tration may not be generalizable to clinical patients withhepatobiliary disease.The results of this study support that NIRFC is safeand feasible in healthy dogs. It consistently providesimproved visualization of the biliary tree. An ICG doseof 0.05 mg/kg given at least 3 –5 h prior to visualizationshould provide excellent contrast between the biliaryducts and liver as well as minimal residual liver fluores-cence, improving visualization during NIRF laparos-copy. Alternatively, a 0. 05 mg/kg dose given at themoment of premedication for general anesthesia is prac-tical for emergent cases and should provide acceptablecontrast and improved visualization. Additional indica-tions could include to aid in the identification of biliarytears when bile leakage has stained the surrounding tis-sues. Further investigations to determine the optimaldose and timing of administration of ICG and the effectsof hepatobiliary disease on NIRFC in canine patientsare underway.AUTHOR CONTRIBUTIONSChagnon Larose P, DVM: Data acquisition, analysis andinterpretation, drafting and revision of manuscript.Brisson B, DVM, DVSc, DACVS, ACVS Founding FellowMinimally Invasive Surgery: Conception and studydesign, data acquisition, analysis and interpretation,drafting and revision of manuscript. Sanchez A, DVM,DVSc, DACVAA: Data acquisition and interpretation,revision of manuscript. Monteith G, BSc: Data analysis.Singh A, BSc, DVM, DVSc, DACVS-SA: Revision of man-uscript. Zhang M. BSc: Data acquisition.ACKNOWLEDGMENTSThe authors would like to acknowledge the ACVS Foun-dation for funding this study. We also acknowledge KarlStorz Veterinary Endoscopy for the loan of near-infraredfluorescence laparoscopic imaging system for this study.The results of this study were presented at the 2021ACVS Virtual Surgery Summit on October 7, 2021 at theVES Annual Conference on June 2, 2022 and at the ECVSAnnual Scientific Meeting on July 10, 2022.CONFLICT OF INTEREST STATEMENTThe authors declare no conflict of interest related to thisreport.ORCIDAmeet Singhhttps://orcid.org/0000-0002-8095-9339

Answer 115

This study is the largest to date exploring the presentingsigns, diagnostic imaging findings, and intra- and periop-erative complications in dogs undergoing TECA-LBOand the first to compare these factors amongst twogroups: EBBs and OBs.4,7,9,10,14The perioperative complication rate of 27.8% is at thelower end of the range of previously reported complica-tions for TECA-LBO (21% –53%).9,21The occurrence ofperioperative facial nerve paresis and vestibular signswere similar to previously reported values.1Wound com-plications occurred in 5.8% of cases which is lower thanpreviously reported (11% –41%).4,14,21However, the dura-tion of follow-up in this study varied from previous litera-ture and direct comparisons should be interpreted withcaution. Despite the perceived increase in the difficulty ofTECA-LBO surgery and the apparent increase in intrao-perative complication rates in EBBs compared with OBs,the difference did not reach statistical significance. Thus,our hypothesis was rejected. This may be a result of lownumbers of intraoperative complications overall and typeI statistical error.Significant hemorrhage was the most encounteredcomplication in this study. The rate and severity ofintraoperative hemorrhage is consistent with previousreports.4,7The other intraoperative complication reportedin the current study was difficulty in the identification ofanatomical landmarks and performing the lateral bullaosteotomy. This was included as an intraoperative com-plication as the surgery diverged from the ideal courseand may have prolonged surgical time. Obtaining intrao-perative information was reliant on details in the surgicalreport due to the retrospective nature of this study. Com-plications may therefore be underreported. The increasedintraoperative complication rate and prolonged surgicaltime in EBBs supports the anecdotal suggestion thatTECA-LBO surgery is considered more challenging inthese breeds. Aberrant bulla location, size, thickness ofthe bony wall, narrow external bony meatus diameterand proximity of neurovascular structures to the surgicalsite account for these perceived challenges.19,22 –24Themorphology and anatomic position of the tympanic bullain relation to the temporomandibular joint in FrenchBulldogs, English Bulldogs, and Pugs differs significantlyfrom all OBs.19This makes visualization of the interior ofthe tympanic bulla more difficult and could theoreticallymake removal of contents more complicated. Thickerbullae walls in French and English Bulldogs, a largeroverlap between the temporomandibular joint andTABLE 6 Perioperative complications in extreme brachycephalic and other breeds.Perioperative complication Extreme brachycephalic breeds (n =81) Other breeds (n =225) p-valueHemorrhage 0 (0%) 4 (1.8%) 227Swelling 1 (1.2%) 9 (4.0%) .230Wound complication 1 (1.2%) 3 (5.7%) .093Note:p-value determined by Pearson's chi-square test.BANKS ET AL . 669 1532950x, 2023, 5, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.13964 by Vetagro Sup Aef, Wiley Online Library on [22/07/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensetympanic bullae in Pugs and French Bulldogs, and smal-ler bullae volume: weight ratios have also been describedin EBBs adding to difficulties in accessing the surgicalsites in these breeds.19Recent studies have also considered these three EBBsto be predisposed to similar conformation-related diseaseprocesses and therefore it was deemed appropriate togroup them as a single category in our study.25–28FrenchBulldogs were the breed most frequently presented forTECA-LBO in our study, representing 49 of 306 total sur-geries.29Previous studies have dichotomized breeds aseither brachycephalic or nonbrachycephalic. However,recent literature suggests that brachycephaly is notbinary.17,18,22,30,31Quantitative skull morphometry hasdemonstrated that dogs with more extreme brachyce-phalic conformations are at higher risk of conditionssuch as BOAS.22They are 3.5 times more likely to have atleast one upper respiratory tract disorder and a signifi-cantly shorter life span than moderate brachycephalic ornonbrachycephalic dogs.15This is supported by our find-ing that all dogs reported to be clinically affected byBOAS were EBBs with almost half of these cases requir-ing previous BOAS surgery. Extreme brachycephalicbreeds also presented more frequently for “other ”reasonsincluding jaw pain. This may be linked to the occurrenceof para-aural abscessation, concurrent OM or the closeanatomic association between the tympanic bullae andthe temporomandibular joint.22This study comparedEBBs to all OBs due to the morphological differencessummarized above. The results could differ if allbrachycephalic breeds were compared to nonbrachyce-phalic breeds.One of our major findings was the difference in pre-senting signs between EBB and OBs. Excluding EBBs,most dogs presented for management of chronic OEwithout neurological signs. This suggests that TECA-LBOis most commonly performed in OBs as a salvage proce-dure for end-stage ear canal disease when medical man-agement fails.21Conversely, EBBs were significantlymore likely to present acutely, at a younger age, with pre-dominantly neurological signs. This is consistent withfindings from previous literature which demonstratedthat younger age was significantly associated with a diag-nosis of OM or OI.32Neurological signs were attributedto OM, OI, or intracranial extension of infection in thesecases. Previous studies have demonstrated that two-thirdsof dogs displaying vestibular signs have a chronic historyof OE in addition to OM.32For that reason, cases withclinical or radiographic evidence of OE in addition to theprimary neurological presenting complaint were stillincluded in the neurological sign category. Fluid accumu-lation in the middle ear can be an incidental finding inbrachycephalic dogs probably due to auditory tube orpharyngeal dysfunction.33Our study demonstrated nodifference in the incidence of middle ear effusionbetween breed groups or presenting sign categories. How-ever, given the predominantly neurological presentationin EBBs and the increase in the diagnosis of OI and brainstem changes, further investigation into the precise path-ogenesis leading to oto-neurological signs in these breedsFIGURE 4 Bar chart demonstrating the perioperative complications in extreme brachycephalic (n =81) and other breeds (n =225).670 BANKS ET AL . 1532950x, 2023, 5, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.13964 by Vetagro Sup Aef, Wiley Online Library on [22/07/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licenseis warranted. The increased incidence of neurologicalsigns may explain the differences in imaging modalitiesperformed in EBBs. Extreme brachycephalic breeds weremore likely to have an MRI alone, or in conjunction withCT than OBs. Whilst CT is considered the modality ofchoice for evaluation of bony structures, MRI providessuperior soft tissue contrast of the membranous laby-rinth, cerebrospinal fluid, and neural structures, allowingeffective differentiation between intra- and extracranialcauses of the cranial nerve deficits.34The increased inci-dence of neurological deficits and identification of OI andbrainstem changes in EBBs suggests that whilst ulti-mately the surgery is the same, TECA-LBO was per-formed for different reasons in these breeds.27,31Thiscould have influenced our results.Perioperative neurological signs were recorded whenn e wa b n o r m a ln e u r o l o g i c a le x a m i n a t i o nf i n d i n g sw e r ee v i -dent postoperatively. Cases that presented with neurologicalsigns were not considered to have neurological periopera-tive complications as it was not possible to determine statis-tically whether postoperative ne urological deficits were dueto pre-existing neurological damage or exacerbated byintraoperative trauma. A greater proportion of EBBs thanOBs presented with neurologic al signs, and intraoperativetrauma resulting in perioperative neurological complica-tions may be underestimated. I atrogenic trauma to the neu-ral structures may have been more prevalent in these dogsdue to the anatomical reasons discussed previously.A greater proportion of EBBs underwent unilateralsurgery and bilateral surgery was more commonly stagedin these dogs, whereas OBs more commonly underwentbilateral single-session TECA-LBO. The surgeon's deci-sion to perform a staged procedure may have been justi-fied based on the anecdotal surgical complexity andincreased surgical time in EBBs. However, in support ofprevious literature, there was no difference in periopera-tive complication rates between unilateral, single-sessionbilateral, and staged bilateral TECA-LBO.7Although positive bacterial cultures were reported in75.6% of cases where culture was taken from the surgicalsite, there was no significant increase in intra- or periop-erative complications in cases that did not receive postop-erative antibiotics. TECA-LBO should be considered aclean-contaminated surgery in cases where the infectionis confined to the external ear canal. A large proportionof patients in this study may have received postoperativeantibiotics unnecessarily if appropriate irrigation wasperformed before closure. The current study does notmake conclusions regarding the impact of postoperativeantibiotics on delayed surgical site infection and para-aural abscess formation. Further research into the use ofpostoperative antimicrobials in patients undergoingTECA-LBOs is warranted.The median duration of hospitalization in EBBs was1 day longer than for OBs. Due to retrospective data col-lection, it was difficult to accurately determine the reasonfor prolonged hospitalization from the clinical records.An explanation may be concern regarding upper respira-tory obstruction, pharyngeal inflammation, regurgitation,or aspiration pneumonia which occur more frequently inbrachycephalic breeds after general anesthesia.35Two dogs did not survive to discharge. Both patientsprogressed to cardiopulmonary arrest following intensivemanagement for severe systemic disease that developedpostoperatively. A post-mortem examination was not per-formed in either case. However, based on antemortemclinical records the cause of death was not considered tobe directly related to the TECA-LBO surgery.One limitation of this study is the retrospective natureof the data collection. Whilst a large amount of relevantdata has been obtained, data collection was reliant ondetails in patient records and surgical reports. This mayhave resulted in underreporting clinical examinationfindings or intraoperative challenges. In addition, all sur-geries were performed at a single institution by diplo-mates or residents in small animal surgery, and socomplication rates, whilst similar to those previouslyreported, may vary between institutions or based on sur-geon experience. Finally, follow-up past the perioperativeperiod was not carried out in this study, and conclusionsregarding delayed postoperative complications such aspara-aural abscessation cannot be drawn. Therefore,direct comparisons between the perioperative complica-tions rate reported in this study and long-term postopera-tive complications reported elsewhere should be madewith caution.In conclusion, this is the first study comparing TECA-LBO in extreme brachycephalic and other canine breeds.Despite being considered more technically challenging,there was no increase in intra- or perioperative complica-tions in EBBs compared to OBs. Extreme brachycephalicbreeds are more likely to present acutely, with neurologi-cal signs, with a higher incidence of OI and brainstemchanges. The complication rates reported in this studyare useful for accurately informing clients of the specificrisks of TECA-LBO surgery in extreme brachycephalicand OBs.AUTHOR CONTRIBUTIONSBanks C, BVMedSci (Hons), BVM BVS (Hons),PGDipVCP, MRCVS: Contributed to the study design,data acquisition, statistical analysis, and interpretationand wrote the manuscript. Beever L, BVetMed (Hons),MVetMed, PGCert, FHEA, DiplECVS, MRCVS: Contrib-uted to the conception and design of the study, dataacquisition, and interpretation and contributed to theBANKS ET AL . 671 1532950x, 2023, 5, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.13964 by Vetagro Sup Aef, Wiley Online Library on [22/07/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensemanuscript. Kaye B, BVSc, MANZCVS (ECC), MVetMed,DipECVS: Contributed to the statistical analysis, andinterpretation of the data and reviewed the manuscript.Foo M, BA(Maths&Socio), PGDE (Math&Eng), BSc,DVM (Distinct): Contributed to the statistical analysisand interpretation of the data. ter Haar G, DVM, PhD,DiplECVS: Contributed to the interpretation of the dataand contributed to the manuscript. Rutherford L, VM&S,MVetMed, PGCert VetEd, FHEA, DiplECVS, MRCVS:Contributed to the conception and design of the study,supervised the data acquisition and interpretation, andcontributed to the manuscript. All authors approved therevised manuscript and are publically accountable for rel-evant content.CONFLICT OF INTEREST STATEMENTThe authors confirm that there are no conflicts of interestto disclose.ORCIDCharlotte Bankshttps://orcid.org/0000-0003-1920-388X

Answer 116

Our study describes the kinematics and kinetics of MLTsfor canine CCLR. All evaluated tests elicit a significantlyhigher CTT in CCL-deficient limbs than in those withintact CCL. The increase in internal tibial rotation andthe reduced force required to achieve translation in theCCLD group reflect the compromised stifle joint stabilityafter CCLR. Interobserver agreement for CTT was excel-lent for all tests, while there was more interobserver vari-ability for rotation and kinetics. For example, the forceapplied when performing CD was highly variable,although the elicited CTT was very consistent. This resultmay be due to our model mimicking acute CCLR. Inthese hyperlax stifles, only minimal force is required toTABLE 1 Cranial tibial translationaduring manual laxity tests.Observer 1 Observer 2 Observer 3 MeanTranslation in mmCDINTACT 2.99 (1.64) 0.55 (1.36) 1.4 (1.11) 1.65 (0.29)CCLD 12.43 (3.08) 10.15 (2.47) 11.36 (1.89) 11.31 (0.58)Differenceb9.43 9.59 9.96TCTINTACT 1.33 (1.15) 1.29 (0.97) 1.03 (0.76) 1.22 (0.2)CCLD 12.6 (3.69) 11.54 (3.04) 11.6 (3.13) 11.91 (0.92)Differenceb11.27 10.25 10.57TPCTINTACT 1.94 (1.27) 1.68 (0.94) 1.94 (1.25) 1.86 (0.3)CCLD 14.15 (3.57) 12.65 (2.12) 13.61 (4.41) 13.47 (0.94)Differenceb12.21 10.96 11.67Abbreviations: CCLD, cranial cruciate ligament deficient; CD, cranial drawer test; INTACT, intact cranialcruciate ligament; TCT, tibial compression test; TPCT, tibial pivot compression test.aShown as mean (standard deviation).bDifferences are the calculated mean of subtraction of INTACT values from CCLD values for each specimenper observer.710 LAMPART ET AL . 1532950x, 2023, 5, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.13957 by Vetagro Sup Aef, Wiley Online Library on [22/07/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licenseelicit CTT, which likely resulted in our observers usingvariable force but still achieving the same CTT. Anotherpossible source of variation is the positioning of the loadcell on the observer's thumb.The highest tibial translation values were elicitedby the TPCT, although this finding was only significantwhen compared to the CD. This finding confirms partof our first hypothesis. The TPCT was developed basedon the human pivot shift test, adding external rotationand valgus stress to the TCT to make rotational insta-bility better palpable. The external moment appliedbefore establishing tibial compression displaces the lat-eral tibial condyle caudally, resulting in greater trans-lation and rotation when the tibia subluxates. Thiseffect of the external rotation may be particularlyimportant in chronic CCLR, where the joint is oftensubluxated when starting the test. Possibly, the TPCTis a more sensitive test to detect subtle instability, asthe tibial translation magnitude may influence theability of the observer to feel tibial motion. The TPCTalso elicited the highest in ternal rotation among alltests; however, this finding did not reach significance.A study with a higher numbe ro fs p e c i m e n sw o u l db enecessary to confirm the second part of our firsthypothesis. Still, this finding seems promising andmight make the TPCT a potential candidate to detectrotational instability. We found a high variability inrotation during TPCT in INTACT when compared toCCLD. This reflects our clinical experience and is mostlikely due to individual variability in screw homemechanism due to different articular surface geometryand soft tissue envelope.The translation and rotation values reported here areslightly higher than the values reported in an in vivostudy during walking.28This can be explained by differ-ent study populations, as the dogs in the in vivo studyhad naturally occurring chronic-degenerative CCLR,while our model mimics hyperlax stifles seen with acuteCCLR. Interestingly, two in vitro studies found highertranslation and rotation values in canine stifles withCCLR than reported here.29,30A possible reason is theirspecimen preparation as the specimen was stripped ofmost soft tissue surrounding the stifle joint, removingpassive restraints of translation and rotation. Neverthe-less, the compatibility of our results with these studies,especially the in vivo experiment during walking, sug-gests that the MLTs used to diagnose CCLR reproducekinematics similar to weightbearing.TABLE 2 Rotationaduring manuallaxity tests.Observer 1 Observer 2 Observer 3 MeanRotation in degreeCDINTACT /C05.8 (9.94) /C03.52 (7.93) /C02.38 (3.76) /C03.9 (1.74)CCLD /C09.8 (10.67) /C08.16 (3.62) /C06.03 (3.35) /C07.97 (1.89)Differenceb/C04.0 /C04.64 /C03.65TCTINTACT /C04.36 (4.9) /C00.36 (3.79) /C02.3 (3.5) /C02.35 (2.0)CCLD /C011.48 (4.14) /C09.19 (7.04) /C010.63 (5.53) 10.43 (1.16)Differenceb/C07.12 /C08.83 /C08.33TPCTExternal rotationINTACT 10.56 (3.38) 11.72 (3.58) 15.88 (3.49) 12.72 (4.09)CCLD 11.64 (4.58) 13.72 (5.16) 18.97 (6.44) 14.78 (6.12)Differenceb1.09 2.01 3.09Internal rotationINTACT /C011.11 (13.5) /C08.05 (14.62) /C01.22 (8.23) /C06.79 (5.06)CCLD /C010.81 (5.6) /C010.4 (6.98) /C013.17 (7.47) /C011.46 (1.49)Differenceb0.3 /C02.35 /C011.95Abbreviations: CCLD, cranial cruciate ligament deficient; CD, cranial drawer test; INTACT, intact cranialcruciate ligament; TCT, tibial compression test; TPCT, tibial pivot compression test.aShown as mean (standard deviation).bDifferences are the calculated mean of subtraction of INTACT values from CCLD values for each specimenper observer.LAMPART ET AL . 711 1532950x, 2023, 5, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.13957 by Vetagro Sup Aef, Wiley Online Library on [22/07/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseWhile the CD is most frequently used in daily prac-tice, its mean interobserver agreement for translation,rotation and kinetics was only moderate. Both TCT andTPCT had better interobserver agreement, with TCTbeing most consistent. This possibly makes those testsmore reliable in the clinical setting. Despite a more stan-dardized testing maneuver, interobserver agreement ofTPCT was not significantly different from the other tests.This could be explained by the higher complexity andunfamiliarity of the testing maneuver. Intraobserveragreement was excellent for translation but only moder-ate to good for rotation and kinetics. Agreement was bestfor TCT and the most experienced observer, indicatingthat practicing MLTs helps improve their reliability. Thesecond hypothesis can therefore be accepted as intraob-server agreement was moderate to excellent, while inter-observer agreement was only moderate to good. The goodintra- and interobserver agreement of the TCT shows thatthe slightly modified testing maneuver used to avoidinterference with the femoral load cell did not impactconsistency. However, we cannot exclude a slight alter-ation of the values due to this different testing maneuver.Qualitative subjective assessment of stifle joint stabil-ity revealed a sensitivity and specificity of 100% for alltests and all observers, which is in line with the first partof our third hypothesis. This result should be interpretedcarefully because our model using CCL tran-section mimics hyperlax stifles, which present with insta-bility that is easily detected by MLTs.4,6Other availablestudies investigating the accuracy of CD and TCT foundless favorable results.7,31Might et al. reported a sensitivityof 97% and a specificity of 82% for the CD for the classifi-cation of intact limbs and limbs with CCLR, caudalTABLE 3 Kinetic measurementsaduring manual laxity tests.Observer 1 Observer 2 Observer 3 MeanCompressive force in NCDINTACT 3.5 (0.61) 2.4 (0.62) 1.76 (0.26) 2.6 (0.9)CCLD 2.57 (0.37) 1.62 (0.23) 1.13 (0.34) 1.77 (0.68)Differenceb/C00.98 /C00.77 /C00.64Axial femoral force in NTCTINTACT 8.25 (3.67) 10.84 (4.4) 7.15 (3.1) 8.75 (3.96)CCLD 5.1 (2.32) 5.42 (1.65) 3.49 (1.26) 4.67 (1.95)Differenceb/C03.15 /C05.42 /C03.66TPCTINTACT 9.3 (3.5) 12.2 (4.74) 10.76 (2.82) 10.76 (3.84)CCLD 6.58 (3.63) 7.06 (4.1) 10.91 (2.0) 8.18 (3.82)Differenceb/C02.72 /C05.15 0.15Abbreviations: CCLD, cranial cruciate ligament deficient; CD, cranial drawer test; INTACT, intact cranialcruciate ligament; TCT, tibial compression test; TPCT, tibial pivot compression test.aShown as mean (standard deviation).bDifferences are the calculated mean of subtraction of INTACT values from CCLD values for each specimenper observer.TABLE 4 Interobserver agreement of kinetics and kinematics.ICC95% Confidence intervalLower UpperTranslationCD 0.95 0.86 0.98TCT 0.98 0.95 0.99TPCT 0.98 0.95 0.99RotationCD 0.54 0.06 0.83TCT 0.87 0.69 0.95TPCT 0.76 0.50 0.89KineticsCD 0.44 0.06 0.76TCT 0.82 0.57 0.93TPCT 0.51 0.04 0.78Note: Agreement is shown as intraclass correlation coefficient (ICC) and 95%confidence interval. ICC >0.9 =excellent, ICC >0.75 =good, ICC>0.5=moderate, ICC <0.5 =poor agreement.27Abbreviations: CD, cranial drawer test; ICC, intraclass correlationcoefficient; TCT, tibial compression test; TPCT, tibial pivot compression test.712 LAMPART ET AL . 1532950x, 2023, 5, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.13957 by Vetagro Sup Aef, Wiley Online Library on [22/07/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensecruciate ligament rupture or rupture of both cruciate liga-ments as “intact ”or“unstable ”in vitro. However, therewas a considerable decrease in sensitivity (69%) and spec-ificity (75%) when the CD was employed to differentiatebetween the pathological conditions. This indicates thateven though participants were able to detect instability,they were unable to identify its origin.31In our study, theCD was able to accurately classify limbs as INTACT orCCLD, which is in line with the results of the study byMight et al. Due to the different study designs, no conclu-sion can be drawn upon the CDs ability to differentiatebetween CCLR and other ligamentous injuries of the sti-fle joint based on our results. In another study, Carobbiand Ness evaluated conscious dogs with naturally occur-ring CCLR and found a sensitivity as low as 60% for CDand 64% for TCT.7Under general anesthesia, sensitivityimproved substantially (up to 92% for CD and 88% forTCT).7Specificity was 100% for both tests in both condi-tions.7This study also included dogs with partial CCLRand duration of lameness before testing was unknown.This might explain the reduced sensitivity compared toour results, as secondary periarticular fibrosis and osteo-arthritic changes reduce stifle joint instability.32Consid-ering this and the excellent interobserver agreement oftibial translation, it appears likely that other factors, suchas presence of pain, periarticular fibrosis, or partial CCLtears, instead of interobserver variability, impair testaccuracy in vivo.The findings in our study surprisingly showed,opposed to the second part of our third hypothesis, thatCTT was subjectively estimated with excellent reliability.A possible explanation for this is that in our experimentalset up resembling acute CCLR there was either minimal(INTACT) or high degree of instability (CCLD), whichenabled the observers to make an informed guess.FIGURE 6 Comparison of subjectively estimated andobjectively measured CTT. The average subjectively estimated CTTsare compared to the average objective kinematic measurements perspecimen. CTT cranial tibial translation.TABLE 5 Intraobserver agreement of kinetics and kinematics.ICC95% Confidence intervalLower UpperTranslationCDO1 0.94 0.75 0.99O2 0.96 0.85 0.99O3 0.94 0.77 0.99TCTO1 0.98 0.916 1.0O2 0.99 0.966 1.0O3 0.93 0.715 0.99TPCTO1 0.95 0.805 0.99O2 0.97 0.866 1.0O3 0.97 0.883 1.0RotationCDO1 0.84 0.36 0.98O2 0.92 0.64 0.98O3 0.45 0.23 0.84TCTO1 0.92 0.652 0.988O2 0.92 0.63 0.98O3 0.58 0.43 0.94TPCTO1 0.77 0.16 0.97O2 0. 77 0.01 0.97O3 0.91 0.64 0.99KineticsCDO1 0.97 0.88 1.0O2 0.23 0.12 0.88O3 0.88 0.55 0.98TCTO1 0.96 0.85 1.0O2 0.92 0.99 0.96O3 0.99 0.95 1.0TPCTO1 0.91 0.63 0.99O2 0.67 /C00.11 0.95O3 0.79 0.07 0.97Note: Agreement is shown as intraclass correlation coefficient (ICC) and95% confidence interval. ICC >0.9 =excellent, ICC >0.75 =good, ICC>0.5=moderate, ICC <0.5 =poor agreement.27Abbreviations: CD, cranial drawer test, ICC, intraclass correlationcoefficient; TCT, tibial compression test; TPCT, tibial pivotcompression test.LAMPART ET AL . 713 1532950x, 2023, 5, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.13957 by Vetagro Sup Aef, Wiley Online Library on [22/07/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseDespite this limitation, our results suggest that a gradingscheme of laxity could be developed for dogs with acutecomplete CCLR.12–14Once validated, a grading systemwould improve the comparability of test results betweenobservers and institutions. Also, in human medicine, spe-cific treatment guidelines have been developed based onthe grading of the pivot shift and Lachman test.33,34Therefore, a grading system for MLTs in veterinary medi-cine could become an essential tool in treatmentdecision-making, for example, when to add an extraarti-cular augmentation after TPLO.The similarity of our results to those of other studiesevaluating kinematics of canine CCLR validates ourmodel as a novel method for testing kinematics in theCCL-deficient stifle.28–30Our testing setup was developedbased on a previously reported setup for human knees.35It was built from 3D-printed components with a load cellseated between the specimen and the testing fixture. Thisdesign makes it very versatile and easily replicated. As nomaterial testing machine is required, it provides a cost-effective and simple solution for performing future stiflekinematics studies. The templates to 3D-print the fixtureare available on request from the corresponding author.Limitations of this study include the small subset ofspecimens, the low number of observers per level of expe-rience and the use of cadaveric hind limbs. Also, CCL-deficiency was mimicked by arthroscopic transection ofthe CCL instead of using limbs with naturally occurringCCLR. Clinical relevance of our results must therefore beconfirmed in subsequent in vitro or in vivo studies withdogs suffering from chronic CCLR.5|CONCLUSIONOur results showed that the CD, the TCT and the newlyintroduced TPCT are accurate an d reliable diagnostic testsin our model resembling acute CCLR. Despite variation inrotation and kinetics between observers, interobserveragreement of CTT was excellent. Following the develop-ment in human medicine, the e stablishment of a gradingsystem could improve accuracy in vivo, as the magnitude ofCTT was estimated with excellent agreement in our experi-mental setting. The TPCT see ms to be promising and mighthave potential for the assessment of subtle or rotationalinstabilities of the canine stifle joint. Further in vivo investi-gations involving dogs with naturally occurring CCLR arewarranted to confirm our findings and to validate the TPCTf o rab r o a d e rs p e c t r u mo fC C Ld i s e a s es c e n a r i o s .AUTHOR CONTRIBUTIONSLampart M, med vet: Involved in all steps of the study.Park BH, PhD, Husi, B, med vet and Pozzi A, MS, ProfDr med vet: Contributed to study design, study execution,drafting and editing of the manuscript. Evans, R, PhD:Contributed to statistical analysis and drafting and edit-ing of the manuscript.ACKNOWLEDGMENTSThe authors would like to thank the team of Prof.Dr. med. vet Michael Weishaupt for their support withthe use of their facilities during data collection. We alsogratefully acknowledge Michelle Aimée Oesch from Vet-com for the photographs. Open access funding providedby Universitat Zurich.CONFLICT OF INTEREST STATEMENTThis study was supported by a grant from the AlbertHeim Foundation of the Swiss Cynological Society.ORCIDMarina Lamparthttps://orcid.org/0000-0002-8310-8302Brian H. Park https://orcid.org/0000-0002-3980-0801

Answer 117

There was no significant difference in the rate of minor and major complications between the SBF and DBF groups (Table 3). Veterinarian-assessed scores and owner-assessed outcomes were better for SBF than DBF (Table 3). Based on veterinarian-assessed scores, SBF was 14.25 times more likely (95% CI 2.07–97.99) to have a suc-cessful outcome with no lameness compared with DBF (P = 0.007) (Table 3). Based on the owner questionnaire, SBF was 9.4 times more likely (95% CI 1.4–61.96) to have a successful outcome with no lameness compared with DBF (P = 0.019) (Table 3). The hypothesis that DBF would Makar et al 11have a lower complication rate and better outcomes was therefore rejected.Radius and ulna fractures in cats comprise 5–13.8% of all long-bone fractures.2,9,11,12 To the authors’ knowl-edge, there are no large cohort studies that document the delayed union rates in cats, so comparisons to dogs are not directly possible. The rate of non-union in the radius and ulna in cats is 16.7%, compared with dogs, in which 17.9% of radius and ulna fractures result in delayed union and there is a non-union rate of 3.4%.11,13 This may be due to the increased motion in the forelimb of cats compared with dogs, with cats having almost double the range of supination.1,9,11 The range of feline antebrachial rotation is most similar to that of humans.14 In human surgery, it is commonplace to plate both the radius and ulna separately in antebrachial fractures due to concerns of increased strain on the fracture site increas-ing the risk of complications.5,7 In this study, there were seven (14.3%) cases of delayed union, which is within the reported range of previous studies; however, this may be higher due to the fact that only 63% of the cases in the present study had follow-up radiographs after the fracture repair.11,12Previous biomechanical studies have shown the poten-tial benefits of DBF in cats.1,3 The authors demonstrated that there was an increase in stiffness where DBF was used compared with single plating of the radius alone. Plating of the radius with the use of an IM pin in the ulna increased stiffness.1,3 In the present study, 1/13 (7.7%) of the DBF cats had major complications; however, this was due to poor vascular viability of the limb at the time of the surgery. This compares with 4/36 (11.1%) cats treated with SBF that required revision surgery. Despite this variation in percentage, the final outcome scores of the veterinarian and owner assessments were significantly better for cases with SBF. This may be due to reduced disruption of the blood supply when plating just one bone, low case numbers or that the fractures themselves were inherently less biologically compromised.8 There may also be a clinical decision bias where DBF may be used in more complex fractures that are less stable and require stiffer constructs as determined by the surgeon. It is important to note that 13/36 (36%) of the SBF cases had either an intact radius or ulna, which would act as an internal splint and potentially aid in the healing of the fracture and making it more likely for them to have a good outcome compared with DBF.An added benefit of DBF in humans may be the reduc-tion of synostosis formation between the radius and ulna, which subsequently reduces the full range of motion and is a significant complication in humans.15 The rate of syn -ostosis after the repair of antebrachial fractures in small animals is largely unknown since the radiographic evi-dence may not be present, but there may be a significant fibrous union between the two bones. Once a synostosis has formed, in humans the complication and recurrence rates are quite high; therefore, avoiding the occurrence of this complication is important.16–18 The consequence of synostosis in cats may be reduced limb function because supination is vital for climbing, grooming, catching prey and hunting.9,19 In the present study, no synostosis was noted in any follow-up radiographs.Of the fractures, 49% were distal, 26.5% were proxi-mal and 24.5% were mid-diaphyseal. This differs from a previous study where the majority of fractures were located in the mid-diaphysis (57.2%), with the proximal and distal diaphysis comprising 25% and 17.8%, respec -tively.8 However, our study is similar to others that show a higher percentage of fractures in the distal diaphysis in cats and small dog breeds.2,20–22 It is important to note that the prevalence of antebrachial fractures in cats is much lower than in dogs: 2–8% and 18%, respectively.2,23 This has previously been hypothesised to be due to higher cortical bone density, thicker trabeculae and increased anisotropy in cats compared with dogs.23 The discrepancy in fracture location between studies may be due to the low numbers of feline antebrachial fractures previously described.8The current literature shows that comminution and high-grade open fractures increase the risk of failure to heal, which is seen in tibial and femoral fractures in cats and in humans.24–27 This is contrary to the results of the present study, where the incidence of major complications in cases requiring revision surgery or even limb amputa -tion was 10.2% and comminution was noted in only two cases (9.5% of all cases with comminution); however, of the remaining cases, three (10.7%) with major compli -cations had no comminution. This was not found to be statistically significant (Table 3). This discrepancy may be due to the sample size included, or the number of cats lost to follow-up in this study. Concurrent orthopaedic issues had an increased percentage of major complica-tions (22.2%) compared with the other cases in the study (7.5%). This is in line with previous reports; however, this was not significant in the present study (Table 3).8The mean time to union of cases that had returned for repeat radiography was 8.8 weeks (range 5–14 weeks). This compares favourably with a previous study where the mean time to radiographic union was 12.9 weeks.8 There was a large proportion of cases that did not return for follow-up radiographs after the original procedure or after initial radiographs. Of 31 cases, 22 (71%) had shown adequate healing of the radius; 5/22 (22.7%) of these cases had delayed union of the ulna. The low number of post -operative radiographs may be due to the clients being satisfied with limb function after surgery and not return -ing for follow-up. This is supported by the results of the telephone interviews, with 92.9% of the cases reported as excellent or good, with only one cat classified as poor and one cat as fair.12 Journal of Feline Medicine and Surgery The authors acknowledge that there are limitations to this study with it being retrospective, involving six referral veterinary hospitals, with cases lost to follow-up, multiple surgeons, various implants and variable after -care instructions. Having a non-standardised method of assessing lameness scores in the different hospitals can be corrected by using force-plate analysis at set time points in the recovery period. To truly understand the difference in clinical significance between single and dual bone plating, a prospective randomised controlled study would need to be performed. However, given the rarity of cats presenting with antebrachial fractures, it would be difficult to achieve a sample size of reasonable signifi -cance. Due to the small number of responses other than 0 for the veterinary assessment score, responses were reduced to a binary outcome (the animal was scored as either lame or not lame), which could have skewed the results as there were fewer responses for DBF. This meant that cases that were mildly lame were grouped with cases that were markedly lame and classed as unsuccess-ful. This could be addressed if there were a larger cohort size in this study. However, this was not achievable with the small dataset, which meant that assessing outcomes as anything more complex than binary reduced statisti -cal power.ConclusionsFeline antebrachial fractures that were managed with SBF had a greater chance of a better outcome as assessed by veterinarians and owners compared with those managed with DBF. The location of fractures in this study is similar to that in other reports, with the majority located in the distal diaphysis, similar to that seen in small and toy-breed dogs. Comminution and concurrent orthopaedic issues did not significantly affect the outcome of cats in this study. Further prospective studies with consistent follow-up, radiographic assessment, surgeon and implants are required to truly assess the difference between DBF and SBF. Although the difference was not significant, cases treated with DBF had a lower inci-dence of major complications, and a higher rate of minor complications.Supplementary material The following files are available as supplementary material: Appendix Table 1: Owner response scores and their description.Appendix Table 2: All cases of feline antebrachial fractures, includes configuration, complications, and final outcomes.

Answer 118

The bilateral superior labial artery composite rotationalflaps were successfully used to reconstruct major defectsof the rostral maxilla, nose, and face in two dogs follow-ing bilateral rostral maxillectomy and nasal planectomyto resect an oral Hi-Lo FSA. As far as the authors areaware this is the first report of this method described indogs. The reconstruction method used in this report wasconsidered technically relatively simple to execute andFIGURE 5 Cosmeticoutcome for Dog 1 (A,B) andDog 2 (C,D) 7 and 2 monthspostoperatively, respectively.KOKKINOS ET AL . 1197 1532950x, 2023, 8, resulted in acceptable functional and cosmetic outcomesin both dogs.Oral tumors represent 6% of all canine tumors30withFSA being among the most common (5% –17%).9,31–33Oral FSA is most frequently found in the canine max-illa9,12,34with reported similar distribution across thehard palate, and rostral and caudal maxilla.9,15A distinctsubtype known as “histologically low-grade, yet biologi-cally high-grade fibrosarcoma, ”seen particularly inretrievers, has been recognized widely.10,13,21Radiologicevidence of bone involvement was found in 63 –78% ofthe cases with Hi-Lo FSA,11,15,34and, based on CT char-acteristics, a periosteal origin was proposed in a recentstudy.13In line with the literature, both dogs in our caseseries were retriever breed-related and had a rostral max-illary mass with osteolytic changes on CT. The clinicallyaggressive behavior of the mass and the histologicalappearance of FSA led to a diagnosis of oral Hi-Lo FSAin both dogs.Oral FSA demonstrates a rapid, locally expansilegrowth35and, although uncommon, nodal and pulmonarymetastases can occur.11,12Local tumor control remainsthe primary goal and several surgical techniques havebeen described.1,3,8,15,20,35 –37Oral FSA had the highestlocal recurrence rates (up to 54%) compared with otheroral neoplasms,8,12,15,16,31,35,38with a recurrence rate of87% in one study.36Incomplete resection has been associ-ated with local recurrence;15however, recurrence hasbeen reported even when tumor-free histological marginsare achieved.15,16Poor outcomes were reported in previousstudies when considering median survival and tumor-freeinterval36and treatment should not differ from thatapplied to dogs with higher grade oral FSAs39favoringearly radical surgical resection in recent years.16,21,22Bothcurrent dogs underwent en bloc resection of the massusing a radical bilateral rostral maxillectomy.Skin-sparing techniques21,37and a combineddorsolateral-intraoral surgical approach20,37have beenreported to reduce surgical trauma and wound complica-tions, and facilitate the surgical approach, maxillofacialreconstruction, and cosmesis. We spared the labial/buccal mucosa flaps (full thickness) bilaterally for thereconstruction of the nose and rostral oral cavity basedon the preservation of the superior labial artery and vein,and terminal branches of the facial artery and vein, oneach side.28The labial artery expands in all the flap layersand has an extended anastomotic network with the infra-orbital artery, enhancing the regional tissue perfusion.28The rotation of the flap in our study was within theacceptable range to avoid compromising its perfusion.28A combined dorsolateral-intraoral approach to completeboth the resection and the reconstruction parts of the sur-gery was used in order to improve surgical accuracy,achieve better control of bleeding, and minimize traumato tissues that were important for the reconstruction. Ini-tially, each dog's recumbency was changed twice intrao-peratively, but the authors believe that performing thesurgery with the patient in one (sternal) recumbency istechnically feasible.Although there is no established method to calculategross surgical margins, it is usual to aim for 1 –2 cm ofmargins in oral oncological surgery.15,16,31Achievingtumor-free margins (>0 mm) can be challenging depend-ing on tumor location, as well as the patient breed andsize. Margin intent in the oral cavity is usually restrictedby anatomical planes and expected patient functionalitypostoperatively.15This makes tumor-free margins lesseasily achieved, particularly in caudally located tumors.16The importance of the nonstandardized “narrow ”histo-logical margins in veterinary medicine was recently ques-tioned and a residual tumor classification scheme wasproposed.40Imported from human oncology, the schemedefines complete histological excision as a histologicaltumor-free margin greater than 0 mm.40In our caseseries, curative intent surgery was performed despite theincomplete staging in Dog 1 . Tumor-free margins wereachieved in both dogs and no gross tumor recurrence wasreported by the owners at 15 ( Dog 1 ) and 6 ( Dog 2 )months postoperatively. The surgical margin intent was2 cm, but histological margins were found to be only upto 5 mm in both dogs. The difference between surgicaland histological margins could be explained by the speci-men shrinkage.40The time elapsed between the CT scan,upon which the surgical planning was based, and the dayof the surgery (32 –34 days for both dogs) could have hadan impact on the progression of the tumors and the histo-logical margins.Perioperative complications are usually common(16%–73%) with oncologic maxillofacial surgery.20,23,27,31,32Excessive surgical bleeding was considered the only ,37orthe most common, intraoperative complication in dogsundergoing partial maxillectomy20,35or oral oncologicalsurgery.23Intraoperative hemorrhage was observed inboth of our dogs, one of which required a blood transfu-sion 8 h after surgery due to a marked drop of the PCValong with cardiovascular deterioration.Epistaxis and difficulty with eating were observedimmediately after surgery in both dogs in our report,which is consistent with previous publications.1,3,20Bothcomplications were considered minor, with epistaxis self-resolving and prehension of food improving gradually inboth dogs during hospitalization.Short and long-term postoperative complications arealso reported when maxilla-na so-facial reconstruction isperformed, with wound dehiscence, stenosis of the recon-structed nares, and profound c hange in patient appearance1198 KOKKINOS ET AL . 1532950x, 2023, 8, being among the main postoperative concerns.3,4,20,23,24,31Wound dehiscence is a major concern regardless ofwhether a surgical revision is required or not, as theconsequential fibrosis contributes to wound contracturethat might alter the anticipated functional and cosmeticoutcome.1,3,16,20,37Maintaining mucosal apposition duringhealing is principally of great importance for a favorableoutcome in maxillofacial surgery, as it promotes primarywound healing and restores a more normal transition fromthe nasal mucous membrane to the mucocutaneous junc-tion.25The labial/mucosal flap is physically robust andtherefore appears to be a viable option for nasal reconstruc-tion following radical planectomy in dogs.25,27The presenceof two asymmetrical flaps, one of which was narrower thanthe other, and the presence of a large defect of exposed con-chae, made the application of the technique published byGallegos et al25unsuitable in our patients.The dogs in our report made full and uneventful recov-eries, without postoperative wound complications. The riskof long-term postoperative complications and the need forsubsequent corrective surgery increases costs, anestheticrisk, and overall recovery time. The owners of either dogwere contacted by the authors for the purpose of followups; no major concerns were raised by the owners of eitherdog, at any given time follow up was requested. Breathingwas reported to remain normal for Dog 1 15 months post-operatively (time of review of the manuscript), as docu-mented by the supplemented material (Video Clip S2).Dog 2 was reported to breathe without any apparent diffi-culty up to 6 months postoperatively after which it was lostto follow up. No specific concerns were raised by the ownerof either dog about breathing during activity. However, reg-ular trimming of the nasal vibrissae on the ventral flap wasconsidered necessary by the owners in both bogs toalleviate local irritation, with owners of Dog 2 specificallyreporting sneezing. This is co nsidered a minor long-termcomplication, which can be managed by the owner athome. Although a larger number of cases will be requiredto show whether this is a commonly repeatable postopera-tive finding, we believe that the potential necessity of regu-lar trimming of the vibrissae should be included in thepreoperative client communication.The potential complications, along with the dra-matic alteration of the dogs' appearance after surgery,might be considered as factors for owners' reluctance orunwillingness to proceed with a curative-intent surgery.The reconstruction method described here offers analternative option that is technically feasible, highlyfunctional and cosmetically a cceptable. Despite initialconcerns about the patency of the nasal passages fol-lowing its coverage by the thick dorsal flap, this did notimpede nasal breathing, and the opening between thetwo flaps appeared to be ad equate to allow normalbreathing. The functional and cosmetic outcomes inboth dogs of this report were considered excellent bythe owners and they would go ahead with the sameprocedure if they were in a similar situation in thefuture.The limitations of our study include the small num-ber of cases presented retrospectively, and the lack oflong-term follow up, including advanced imaging. Dog2was lost to follow up after 6 months. Although clini-cal surveillance for disease recurrence was advised inboth cases, this was declined by the owners of bothdogs. A technical limitation o ft h ed i s t a n t / p h o n ef o l l o wup is that the authors were not able to clinically assessand document via photographs the gross outcome onanatomical structures of surgical and clinical interest.Further documentation showing the nasal passages wasrequested; however, the owners were reluctant to liftthe dorsal flap and take videos and/or photographs ofthe nasal passage due to their concerns about damagingthe flap.As far as the authors are aware, this is the first reportto describe the use of full-thickness bilateral labial/buccalrotational flaps of the superior labial artery for the suc-cessful reconstruction of major defects of the rostral max-illa, external nose, and facial defects involving the nasalcavity, following radical bilateral rostral maxillectomyand nasal planum resection. The flaps described offerexcellent functional and cosmetic outcomes in dogs andcan be considered for naso-facial reconstruction inselected cases.ACKNOWLEDGMENTSAuthor Contributions: Kokkinos P, DVM, MSc (SAS):Assisted in surgery, acquisition of the clinical and imagingdata. Drafted, revised, and approved the submitted manu-script. Elliott J, BVM&S, CertSAM Dipl. ECVIM-CA(Onc), DACVR (RadOnc): Revised and approved the sub-mitted manuscript. Almansa Ruiz JC, DVM (Hons), MSc(Vet), Dipl. EVDC: Lead surgeon. Acquisition of imagingdata. Revised and approved the submitted manuscript.The authors would like to thank Dr. Keri-Lee Dobbiefor proofreading the manuscript and suggesting severalcorrections to improve the final outcome. The authorswould also like to thank Dr. Stamatina Giannikaki forkindly providing the illustrations in Figure 4.FUNDING INFORMATIONLinnaeus Veterinary Limited supported the costs ofpublication.CONFLICT OF INTEREST STATEMENTThe authors declare no conflict of interest related to thisreport.KOKKINOS ET AL . 1199 1532950x, 2023, 8, ORCIDPanagiotis Kokkinos https://orcid.org/0000-0002-8305-1924

Answer 119

The first aim of this study was to report the prev -alence of fractures of the medial coronoid process associated with humeral condylar fractures in a pop -ulation of dogs and cats. The prevalence of such pre -sumed concurrent fractures was high (26/57 in total, 25/49 dogs and 1/8 cats), with almost 1 out of 2 cas -es in our study having a suspected fractured medial coronoid process in addition to a humeral condylar fracture. Contrary to our initial impression, the T/Y type of condylar fracture was not significantly asso -ciated with a higher prevalence of possible fractured medial coronoid processes, with a high prevalence also noted in lateral and medial condylar fractures. The actual mechanism of this presumed fracture is unknown, but it can be suspected to result from forces exerted by the medial coronoid process on the humeral condyle during the traumatic event. In cases of humeral incomplete or delayed ossification, however, the force of the trauma does not need to be severe, especially in French Bulldogs.9 Medial and T/Y condylar fractures have been reported to occur after a humeroulnar interaction, whereas in lateral condylar fractures the interaction is mainly between the humerus and radius.9 It has been proposed that even if the medial aspect of the humeral condyle is not directly affected, subsequent joint subluxation/luxation could mean that forces on the medial com -partment of the elbow joint from the dislocated ma -jor medial fragment would result in fracture of the medial coronoid process via shearing forces.4 In our study, elbow luxation or subluxation most often af -fected the humeroulnar joint, suggesting that a dis -placed trochlea could result in forces applied on the medial compartment, possibly resulting in a con -comitant fractured medial coronoid process.The only significant parameter associated with a higher prevalence of a suspected fractured medial coronoid process was the comminution of the humer -al condylar fracture. It could be speculated that the force of trauma associated with comminuted fractures was more severe, thus leading to increased loading of the medial compartment of the elbow joint, resulting in a fractured medial coronoid process. It could also be suspected that the presumed fractured medial cor -onoid process was mistaken for a bone fragment from the comminuted fracture of the humeral condyle. However, considering that some of the cases with a fractured medial coronoid process also showed a blunted medial coronoid process, this seems unlikely.Another possible origin of the fragment could be an avulsed medial collateral ligament. However, given the more distal attachment of this structure on the radius and ulna and the absence of a visible de -fect in the area of its attachment, this seems unlikely. Furthermore, the presence of 2 crura with different attachment sites makes it seem less likely that the avulsion fragment would be displaced so proximally.In our case series, the suspected fractured medi -al coronoid process was considered as an incidental and concomitant finding and was, as such, not treat -ed. The clinical relevance of such a fracture is un -known and was beyond the scope of this study. None of the patients in this study were treated regarding the presumed fractured medial coronoid process, and the region was not explored during surgery.Fragmented medial coronoid process is a dis -ease that mainly affects large- to giant-breed dogs.10 Most (33/49) of the dogs in our study were consid -ered to be small- to medium-breed dogs. It seems unlikely that the dogs included in our study would have presented signs of elbow dysplasia prior to their presentation for the humeral condylar fracture. Furthermore, even though diagnosis of fragmented medical coronoid process is limited on radiographs alone, out of the 56 animals that had a unilateral fracture, 32 had imaging of the elbow of the contra -lateral limb and showed no signs of fragmented me -dial coronoid process. Also, the irregular surface of the adjacent remaining medial coronoid process re -inforces our hypothesis that this fragmentation was of traumatic origin. The dogs in our study were main -ly dogs predisposed to humeral condylar fractures and, in particular, chondrodystrophic dogs, including French Bulldogs.6 When contralateral radiographs were available, no radiographic signs of incomplete ossification of the humeral condyle were noted even though the positioning was not always adequate, and radiography is not the modality of choice.The dogs and cats in this study were mostly young, with 75% of those included in the study being younger than 13 months and the median age of those included being 4 months. This is inherent to the fact that humeral condylar fractures are often considered as Salter Harris–type fractures and traditionally affect young patients.6,10 The distribution of these humeral condylar fractures and the breeds affected are con -sistent with what has been previously published, with lateral condylar fractures being the most frequent and breeds such as French Bulldogs being the most affected.11 The growth pattern of the medial coronoid process has been described in growing dogs. A study has shown that the medial coronoid process ossifies from base to tip.12 This means that in younger pa -tients, the tip of the medial coronoid process remains cartilaginous and therefore radiolucent. Therefore, fractures of the immature medial coronoid process could have been underestimated in some of our cases.More than half of the fractured elbows were sec -ondary to a fall from a height (35/58). However, a particular type of trauma was not associated with the presence of a suspected fractured medial coronoid process. It has been speculated that trauma while the elbow is partially flexed could be responsible for fractures of the medial coronoid process alone.1–3,13Unauthenticated | Downloaded 12/24/23 09:32 AM UTC6 Unsurprisingly, the size of the presumed medial coronoid process fragment increased significantly with the weight of the dogs or cats included in the present study. Even though no statistical significance was established, fragments seemed to be smaller in chondrodystrophic dogs, which are generally small-breed dogs. This could be due to the fact that the medial coronoid process has been shown to be smaller in chondrodystrophic dogs.14 Furthermore, the size of the fragment could be underestimated due to the radiographic nature of the study.Our study had several limitations that were in -herent to its retrospective and merely observational nature. First, the diagnosis of a suspected fractured medial coronoid process was based on radiograph -ic findings only. In our institution, CT scans are not routinely performed on fractures of the humeral condyle. The gold standard for the diagnosis of frag -mented medial coronoid processes is arthroscopy or CT scan,15 which were not performed in any of our cases. The actual number of medial coronoid process fractures could have therefore been underdiagnosed. Furthermore, these fragments could have originated from other structures surrounding the elbow, which cannot be confirmed merely by radiography. How -ever, in one-third of the cases, the medial coronoid process was clearly blunted, adjacent to the identi -fied fragment, and given the mechanism of the frac -ture and size of the fragments, radiographs may have been sufficient to identify presumed medial coronoid process fractures in this particular context.Second, positioning of the patients during radio -graphic examination was variable, especially consid -ering the fractured distal humerus. Two orthogonal standard views of the elbow were not always avail -able. This probably explains why some presumed fractures of the medial coronoid process were only visible on the postoperative radiographs. A specific oblique radiographic view (cranio- 15° lateral-cau -domedial oblique view), which is commonly used in the diagnosis of fragmented medial coronoid pro -cess,16 had been proposed to better visualize the fractured medial coronoid process in 1 case report.2 This view was not performed on any of our patients but could have helped in identifying more possible fractures of the medial coronoid process.None of the patients underwent an ortho -pedic assessment prior to the traumatic event. Hence, underlying elbow dysplasia and, in partic -ular, fragmented medial coronoid process could have been present before the trauma. As most of our patients were extremely young and belonged to breeds not typically affected by elbow dyspla -sia, this seems unlikely.In conclusion and according to this observa -tional radiographic retrospective study, particular attention should be taken when evaluating cases of humeral condylar fractures for a potential associated fractured medial coronoid process, even more so in comminuted fractures, where the risk of a suspected fractured medial coronoid process is estimated to be 4 times more likely. Further studies are warranted to determine the clinical impact of such a condition.AcknowledgmentsE. Pierrot, DVM, contributed to the collection of the data and writing and revision of the manuscript. G. Bolen, DVM, PhD, DECVDI, contributed to the collection of the data and writing and revision of the manuscript. Bernard M. Bouvy, DVM, MS, DECVS, DACVS, contributed to the collection of the data and writing and revision of the manuscript. Marc H. Balligand, DVM, PhD, Cert SAO, DECVS, contributed to the collection of the data and writing and revision of the manu -script. Pierre P. Picavet, DVM, MS, DECVS, contributed to the study design, collection of the data, and writing and revision of the manuscript.The authors would like to thank M. Ernst, PhD, from Bio -statistics and Research Method Center, for analyzing data for statistical significance.DisclosuresThe authors have nothing to disclose. No AI-assisted technologies were used in the generation of this manuscript.FundingThe authors have nothing to disclose.

Answer 120

The results of this study showed that the dome trochleoplasty procedure can be effective for correcting patellar luxation associated with patella alta in dogs weighing greater than 20 kg, demon -strated by the improved median lameness and CBPI survey scores during the study period. However, for reliable results, the procedure should be performed in conjunction with other corrective procedures, such as tibial tuberosity transposition, soft tissue imbrication, and/or soft tissue release to minimize the risk of re -luxation, and surgeons should consider that implant removal may also be required following bone healing.The advantages of the procedure are its simplic -ity; its versatility in correcting a variety of patellar abnormalities, including patella alta; and the preser -vation of the entire articular cartilage surface area. A biradial saw blade was used to allow for the osteoto -mized segment to move proximally to correct patella alta but also to allow for medial or lateral rotation to increase the medial or lateral trochlear ridge height in cases of trochlear hypoplasia, which can be seen in many cases of patella luxation. The size of saw blade was chosen at the discretion of each surgeon to al -low for an osteotomy of the entire femoral trochlea. In cases of MPL, hypoplasia of the medial trochlear ridge allows for unimpeded luxation over the shorter trochlear ridge. The dome trochleoplasty allows for either rotation of the segment medially to increase the medial trochlear ridge height or to rotate the segment 180° to use the lateral trochlear ridge to achieve appropriate medial stability. While there would be concern that decreasing the lateral trochle -ar ridge height would predispose the dogs to lateral patella luxation, this was not seen in our study popu -lation. While distal tibial tuberosity transposition and tibial tuberosity advancement do exist to correct patella alta, they do not allow for the simultaneous correction of multiple abnormalities associated with patella luxation.14,15 The dome trochleoplasty tech -nique can correct the issues with trochlear depth and malalignment of the quadriceps mechanism contrib -uting to patella luxation and patella alta pathology simultaneously, potentially decreasing surgery and anesthesia time. Additionally soft tissue imbrica -tion or releasing incisions may also be required to further prevent relaxation, but these can be done as part of incision closure and should not significantly increase surgery or anesthesia times. Further study is warranted using objective assessment measures, such as force plate gait analysis, and assessment of long-term outcomes, which is beyond the scope of this study.The overall complication rate for the dome trochleoplasty procedure was 50%, which was signifi -cantly higher compared with previously reported pa -tellar luxation procedures.3,6–9 Major complications occurred in 43.8% of stifle joints (7/16 stifle joints), and catastrophic complications occurred in 1 stifle. Of the 7 stifle joints with major complications, 4 were due to pin migration from the dome trochleoplasty site, and the associated lameness resolved after pin removal. While considered a major complication, pin removal is a routine, straightforward procedure and can often be performed under sedation rather than general anesthesia. To limit pin migration, the use of threaded Kirschner wires or bioabsorbable pins could be employed, but additional studies would be necessary to evaluate the efficacy of these implants in preventing such migration. One dog had a cata -strophic complication at 16 weeks postoperatively and was treated with a patellar groove replacement. In that case, it was suspected that vigorous activity early in the postoperative period may have led to disruption of the osteotomy blood supply and heal -ing that resulted in significant, progressive bone re -sorption. This complication reinforced the directive for postoperative convalescence and activity restric -tion. Alternatively, excessive heating of the bone could have occurred during the osteotomy, leading to thermal injury and necrosis of the bone. Thermal injury can be mitigated by lavage during the oste -otomy to cool the tissues.Recurrence of patellar luxation postoperatively occurred in 19% of stifle joints (3/16 stifle joints) and required a second surgery to achieve proper reduc -tion. Our reported reluxation rate was significantly higher than recent reports8,9 of 6% to 6.4% involving small- to large-breed dogs. In each of these 3 cases, only the dome trochleoplasty was performed to cor -rect the patellar luxation and patella alta. Each case of recurrent reluxation was treated with tibial tuber -osity transposition, medial retinacular release, and lateral imbrication, which led to correction of the luxation. A 2007 study by Arthurs et al16 found that dogs > 20 kg had a significantly higher risk for com -plications and reluxation but also found that dogs undergoing both trochleoplasty and tibial tuberosity transposition were less likely to encounter complica -tions and reluxation. Given the findings of that study and our results, we would recommend that soft tis -sue procedures, such as soft tissue imbrication and soft tissue release, and tibial tuberosity transposi -tion be performed in addition to the dome trochleo -plasty, especially in dogs with higher-grade patellar luxation, to minimize the risk of recurrent luxation.While simple to perform, the dome trochleo -plasty procedure does have some limitations. First, the surgeon must ensure that the entire trochlea Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 11/03/23 06:54 AM UTC6 is excised with enough bone to prevent fracture of the exposed trochlear ridge. Second, there is the need for a biradial saw blade and specialized train -ing to use this equipment. Finally, given that there are no set measurement protocols, the outcome of this procedure is dependent on the surgeon’s abil -ity to judge appropriate positioning of the resected trochlear segment. Further research may produce such necessary measurement protocols. The major limitations to the current study include a small sam -ple size and the large percentage of patients lost to follow-up. Additionally, the subjective nature of the postoperative outcome evaluation by owners and veterinarians may lead to overestimation of clini -cal effect. The follow-up period was also relative -ly brief, with maximum follow-up being 6 months postoperatively. Long-term follow-up would be valuable for evaluating patient outcome and pro -gression of osteoarthritis.The findings of this study led us to reject our hypothesis and instead to suggest that when used alone, the dome trochleoplasty would not be rec -ommended for surgical correction of patellar luxa -tion and patella alta in large-breed dogs due to its higher complication and reluxation rates than those of previously reported procedures. Dome trochleo -plasty may possibly be used, cautiously, in combi -nation with other corrective procedures rather than as a stand-alone procedure. While the major com -plication rate was higher than in previous studies, the majority of complications were due to pin mi -gration. Subsequent removal, which is a simple pro -cedure and can be done under sedation, resulted in favorable outcomes. Further studies are warranted to investigate strategies to minimize pin migration, to investigate the potential use of dome trochleo -plasty in smaller-breed dogs, and to better assess long-term clinical outcomes.AcknowledgmentsDr. Ericksen acquired data and drafted the manu -script. Dr. Stobie was involved in study design, performed the procedure, and critically revised the manuscript. Dr. Culbert performed the procedure and critically revised the manuscript. Dr. Valenzano critically revised the man -uscript. Dr. Bogart performed statistical analysis. All au -thors approved the submitted manuscript.An abstract of this study was presented in part at the Sixth World Veterinary Orthopedic Congress and the 49th Veterinary Orthopedic Society: Scientific Abstract Presenta -tion, Snowmass, Colorado, February 2022.The authors thank Kathleen Beck for medical illustrations.DisclosuresThe authors have nothing to disclose. No AI-assisted technologies were used in the generation of this manuscript.FundingThe authors have nothing to disclose.

Answer 121

We performed transcatheter shunting vascular embolisation using the AVP II and AVP IV in four dogs with left splenophrenic shunt. The AVP II and AVP IV are effective embolic devices that can completely occlude blood flow with a single device in a sim -ple procedure. This is the first description of AVP II and AVP IV for the treatment of splenophrenic shunts in dogs.In this series of cases, we used preoperative cefovecin, a long- acting cephalosporin antibiotic, to mitigate the risk of infection when placing an internal implant. However, due to concerns of drug- resistant bacteria, we now use a shorter- acting cephalo -sporin (cefazolin 20 mg/kg intravenously q 90 min) to prevent infection during the procedure, and do not use preoperative long- acting antibiotics.The AVP is used in human medicine for peripheral vascular embolisation of medium to large blood vessels with high blood flow. The AVP is reported to migrate less than the coil, and com -plete occlusion can be accomplished with one device (Ramakrish -nan 2015 ). The recommended size of the AVP 30% to 50% larger than the internal diameter of the vessel (Ramakrishnan 2015 ). In veterinary medicine, there are two reports using vascular plugs for CPSSs. The AVP I was used to treat dogs with congenital extrahepatic portosystemic shunt (Hogan et al. 2010 ). After tem -porarily occluding the shunt, the balloon catheter was removed and replaced with a vascular sheath, and the plug was deployed. Seven AVP were deployed in six dogs with complete occlusion of the EHPSS achieved in five of six dogs. Another report described the use of a septal occluder device (Amplatzer Septal Occluder; AGA Medical Corp., Golden Valley, MN, USA) with a 7- Fr delivery sheath in the treatment of dogs with congenital intrahe -patic portosystemic shunts after confirming that portal pressure did not increase significantly after temporary clamping (Weisse et al. 2005 ).The AVP II and AVP IV were used in this study. The AVP I occludes flow with two nitinol meshes, whereas the AVP II uses six nitinol meshes, making it more embolic and likely that a single plug can completely occlude blood flow. However, the AVP II has an overall length requirement, which requires a shunting vessel of sufficient length. In Cases 3 and 4, the com -pression method was used to overcome this limitation. The plug can be shortened to 58% (±5.9%) by pushing the delivery wire. FIG 4. Intraoperative fluoroscopy images of shunting vascular embolisation in Case 3. (A) The catheter is inserted into the left phrenic vein, and the portal pressure is 11 mmHg with the balloon dilated in the shunting vessel beyond the confluence of the left hepatic vein. (B) Angiography is performed from the same site to confirm the shunting blood vessel (arrow) and the intrahepatic portal vein branch (arrowhead). (C) An Amplatzer vascular plug (AVP) II (arrow) with a diameter of 14 mm is deployed at the same site. (D) Angiography is performed to confirm complete blockage of blood flow at the location of the AVP II (arrow)Table 2. Serum biochemistry before and after AVP placement in four dogs with splenophrenic shuntCase 1 Case 2Pre 1 day 2 days 50 days Pre 1 days 3 days 9 days 138 daysALT (U/L) 178 167 154 107 789 982 850 149 151ALP (U/L) 139 227 218 292 222 474 407 259 57NH3 (μg/dL) 78 27 24 64 29 27 38 42TP (g/dL) 5.1 5.7 5.4 5.5 5.7BUN (mg/dL) 11.2 12.8 17.4 18.8 15.4 16.4Glu (mg/dL) 100 117 108 108 114 127 118Case 3 Case 4Pre 1 day 2 days 10 days 27 days Pre 1 days 2 days 11 days 24 daysALT (U/L) 212 164 187 136 431 532 487 252 189ALP (U/L) 101 142 136 116 231 214 228 91 81NH3 (μg/dL) 294 32 23 50 37 218 52 56 65 58TP (g/dL) 6.3 5.8 5.5 5.7BUN (mg/dL) 8.7 9.2 9.7 7.3 8.2Glu (mg/dL) 90 96 98 96 78 90AVP Amplatzer vascular plug™, ALT Alanine aminotransferase, ALP Alkaline phosphatase, NH3 Ammonia, TP Total protein, BUN Blood urea nitrogen, GLU GlucoseReference range: ALT , 17 to 78 U/L; ALP , 47 to 254 U/L; NH3, 16 to 75 μg/dL; TP , 5.7 to 7.8 g/dL; BUN, 17.6 to 32.8 mg/dL; GLU, 71 to 148 mg/dL 17485827, 2023, 11, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jsap.13660 by Vetagro Sup Aef, Wiley Online Library on [15/11/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseY. Kawamura et al.Journal of Small Animal Practice • Vol 64 • November 2023 • © 2023 British Small Animal Veterinary Association. 716Shortening the plug does not reduce embolic force or result in histologic damage to the vessel (Matsumoto et al. 2019 ). The AVP IV used in Cases 1 and 2 has four nitinol meshes to occlude blood flow, has a smaller diameter than the AVP I, and can be delivered via catheters that allow 0.038- inch guidewire. The AVP IV is also more flexible, and can be used in curved blood ves -sels. In the two present cases, the plug could be placed without replacing the 5- Fr balloon catheter used to temporarily block the shunting blood vessel. This simplifies the procedure and reduces radiation exposure to both the dog and the operator. Since the AVP IV has a diameter of up to 8 mm, it can be used in shunting vessels up to 5 to 6 mm diameter.Should portal hypertension result from placement of the AVP , identifying the shunt at the level of the plug suturing the thin- walled shunting vessel after removal of the plug would be more technically challenging than removing a ligature or a thin film band that causes portal hypertension. In addition, performing a venotomy reduces the diameter of blood vessels and increases the risk of thrombosis at the site of venous suturing, leading to portal hypertension. The surgical approach could be especially difficult in small dogs and therefore would be a limitation of this procedure.In splenophrenic shunts, the vessel flattens and narrows dur -ing inspiration when the diaphragm contracts, reducing blood flow through the shunting vessel and increasing blood flow to the portal vein. Intrahepatic portal vein branches are generally well developed, and shunting blood vessels can often be com -pletely blocked in the first stage (Fukushima et al. 2014 ). In our four cases, well- developed portal vein branches were confirmed by presurgical CT. Shunting vessels can be completely occluded in one stage if the portal pressure during temporary blockage is 15 mmHg or less (Hottinger et al. 1995 , Broome et al. 2004 ). In our cases, the portal pressure was less than 15 mmHg in all dogs, and occlusion was accomplished in one phase. The embolisation technique used in this study is applicable only when the shunting vessel can be completely occluded in one step, and appears to be suitable for some splenophrenic shunts.The blood vessels in the splenophrenic shunt are flattened with an oval cross- section. To select the size of plug, the outer boundary of the cross- section of the vessel was measured from the CT images, the approximate diameter was estimated by dividing the outer boundary by the circumference ratio, and the plug was selected with a diameter 30% to 50% greater than that of the shunting vessel (Ramakrishnan 2015 ). The diameter was calculated by dividing the circumference as if it was that of a completely round vessel. In all cases, the selected plugs fit the shunting vessel.Limitations of this case series include the small number of cases. However, splenophrenic shunts are relatively com -mon in small- breed dogs, and our four cases appeared to rep -resent a population of common splenophrenic shunts. Ideally, we would further investigate the usefulness of this method by increasing the number of cases. This technique is only applica -ble when single- stage complete closure appears to be acceptable and the risk of postoperative portal hypertension is considered low. We assessed shunting vessel occlusion by intraoperative angiography and decreased postoperative levels of preprandial ammonia. Postoperative CT angiography and ammonia toler -ance test should be included in future study designs.This retrospective case series describes the use of AVP II and AVP IV for minimally invasive treatment of splenophrenic shunts in dogs. Interventional treatment with the AVP IV for splenophrenic shunts, one of the most common shunts in small dogs, is feasible and has the advantage that one plug can com -pletely occlude the blood flow of the shunting vessel. The AVP IV is appropriate when the diameter of the shunting vessel is 5 to 6 mm, and the procedure can be completed with a balloon cath -eter alone. We also found that it was effective to extrapolate the vessel diameter from the measured length of the outer boundary of the cross- section of the vessel on the CT image when deter -mining the size of the plug to treat splenophrenic shunts.AcknowledgementsWe would like to thank Masahumi Kanoto (Yamagata University Hospital) for his technical assistance.Author contributionsYuta Kawamura: Conceptualization (lead); methodology (lead); writing – original draft (lead). Kenji Kawamura: Writing – review and editing (equal). Hiroki Itou: Writing – review and editing (equal). Akitomo Kida: Writing – review and editing (equal). Hiroki Sunakawa: Writing – review and editing (equal). Moe Suzuki: Writing – review and editing (equal).Conflict of interestNone of the authors of this article has a financial or personal relationship with other people or organisations that could inap -propriately influence or bias the content of the paper.

Answer 122

Historically, curative-intent RT treatments have been utilized in the treatment of both feline and canine intracranial tumors.3,6,10,11,17,18,23–26 However, there is a paucity of literature on feline patients diagnosed with intracranial meningiomas treated with SRT. In a 2003 paper by Troxel et al,1 a total of 4 cats under -went RT for treatment of presumed intracranial me -ningiomas; however, the radiation protocol was only specified for 1 cat that received 3 doses weekly of 400 cGY for a total dose of 48 Gy. This cat survived 240 days and was euthanized for an unrelated neoplasm.1 Sessums and Mariani10 reported treating 2 cats with MRI-diagnosed cerebral meningiomas using a linear accelerator–based SRT unit; however, the case series is unpublished and data cannot be gathered from this review. Eleven client-owned cats with MRI-diagnosed pituitary tumors were treated with modified linear ac -celerator–based radiosurgery receiving 1 to 3 treat -ments.19 Improvement in clinical signs was noted in 63.6% of treated cats, and there were no confirmed acute or late adverse radiation effects.19 In the larg -est and most recent study evaluating the outcome of cats with intracranial tumors treated with RT, 21 cats were treated with various definitive-intent daily frac -tionated protocols, from 3 to 20 fractions.6 The single case that received 3 fractions was diagnosed with a choroid plexus tumor and was censored at 588 days post-treatment.6 Eleven cats were diagnosed with meningioma and received anywhere from 10 to 20 fractions of between 40 and 45 Gy (total dose), with an average overall survival time of 315 days (range, Table 3 —Summary of characteristics of the 14 cases with documented recurrence of meningioma following surgery as initial treatment for intracranial meningioma. No. Time Tx Case Clinical of to for No. Age Sex Breed Location signs Subtype recurrences recurrence recurrence Outcome13 7 MN Maine Coon Forebrain Behavior, gait changes, MT 1 72 mo Craniotomy Alive CN deficits17 10 MN DSH Forebrain Behavior, gait changes, PS 1 37 mo Craniotomy Alive CN deficits, other20 8 MN DSH Forebrain Seizures N/A 2 36 mo; 12 mo RT (18 tx); Euthanized due to RT (3 tx) other disease, 11 mo later30 12 MN DSH N/A Behavior change N/A 1 12 mo RT (3 tx) Died, 48 mo late, neurologic signs noted 31 15 MN DSH Forebrain Seizures PS 1 9 mo None noted Lost to follow-up35 10 FS DSH Forebrain N/A N/A 2 53 mo; 65 mo Craniotomy; Lost to follow-up meds36 12 MN DSH Forebrain Behavior changes, N/A 1 5 mo Meds Died, 25 mo, no neurologic CN deficits signs noted38 12 MN DSH Forebrain Mentation changes PS 3 12 mo; 24 mo; Craniotomy; Lost to follow-up 24 mo craniotomy; RT (3 tx)41 9 MN DLH Forebrain Behavior, gait changes, FB 1 48 mo RT Euthanized due to recurrence CN deficits of neurologic signs, 22 mo later46 10 FS DSH Forebrain Behavior, gait change N/A 2 10 mo; 12 mo Craniotomy; Lost to follow-up meds49 15 MN Persian Forebrain N/A N/A 1 21 mo Meds Lost to follow-up58 14 MN DSH Forebrain Mentation, gait change, PS 2 1 mo; 17 mo RT (1 tx); Lost to follow-up CN deficits RT (3 tx)60 13 FS DSH N/A Behavior change N/A 2 5 wk; 39 mo Craniotomy; Euthanized due to seizures, RT (3 tx) respiratory distress, 16 mo later61 8 FS DSH Cerebellar N/A N/A 1 60 mo RT (3 tx) Euthanized, not for neurologic signs, 20 mo laterDLH = Domestic longhair. FB = Fibroblastic/fibrous variant. MT = Meningothelial . N/A = Not applicable. PS = Psammomatous. Tx = Treatment.See Table 2 for remainder of key.Unauthenticated | Downloaded 12/24/23 09:26 AM UTC6 50 to 963 days).6 Three cats were alive at the time of data evaluation (overall survival range, 121 to 225 days), 1 cat was reirradiated resulting in an additional progression-free interval of 223 days, and 3 cats died from tumor- or treatment-related causes.6In this paper, we reported the outcome of either surgery or SRT for the treatment of intracranial me -ningiomas in a subset of feline patients. As previous -ly noted, the MST for surgically treated intracranial meningiomas in cats is 693 to 1,125 days (22.8 to 37 months)1,9,12,13 with a 2-year survival rate of 50%13 in the literature. In this study, cats that had initial sur -gery were found to have an MST of 1,345 days, which is equivalent to 44 months. Median survival time for cats in the SRT group was 339 days, equivalent to 11 months. The difference in MST between the surgery group and the SRT group did reach statistical signifi -cance ( P = .002; Figure 1). The MST for the SRT group is below the documented MST for surgical treatment; however, it is close to the value noted in the single case that received 3 fractions of SRT and lived for 240 days described by Troxel.1 Historically, RT has been utilized in lesions not easily accessible by sur -gical approaches in human and veterinary medicine. No known literature is available that evaluates the re -lationship between the intracranial location of feline meningiomas and prognosis and rate of recurrence; however, in a 2009 paper by Klopp et al30 discussing endoscopic-assisted meningioma removal in dogs, the MST for dogs with forebrain meningiomas was significantly longer when compared with the dogs with caudal brain/brain stem meningiomas ( P = .05). In that paper, the MST for forebrain meningiomas was 2,104 days compared with 702 days for caudal brain meningiomas.27 Forterre et al15 found that for tumors in less-accessible locations, such as tentori -ally located meningiomas, survival time was found to decrease to 19 months (578 days) postoperatively in feline patients. Lesion localization between the 2 groups in the current paper nearly reached signifi -cance ( P = .07; Table 1) with the only 3 lesions lo -cated in the brain stem in the SRT group. Location of the tumor may have contributed to the lower MST found in the SRT group.A single cat in the SRT group and 5 cats in the surgery group were noted to have 2 or more masses located within the brain at the time of diagnosis. In addition to single meningioma, there is also a high in -cidence of multiple meningiomas in cats noted in the literature.28 In a 2003 paper1 retrospectively review -ing feline intracranial neoplasms, 17.2% were found to have multiple meningiomas at the time of diagnosis. A 2007 paper28 evaluating multiple meningiomas in cats that underwent surgery suggests that the post -operative outcome does not seem to be influenced by the number of meningiomas present. This paper evaluated only 4 cats, all of which had surgery to re -move the masses, and they all were administered hy -droxyurea postoperatively in an attempt to diminish tumor regrowth.28 While the number of cases diag -nosed with multiple tumors in this paper was low, the effect this finding had on the outcome of both treat -ment groups was not explicitly evaluated and there -fore cannot be disregarded. Significantly more cats in the surgery group had peritreatment complications compared to the SRT group ( P < .0001). The most common peritreatment complication in the surgery group was anemia (54%), and 1 case developed sei -zures following surgery and arrested. A paper13 that evaluated 42 cats that underwent surgery for their intracranial meningiomas reported 31% of cases were anemic postoperatively (range, 10% to 25%) and 19% died or were euthanized in the immediate postopera -tive period. Intracranial hemorrhage can be significant during surgery and can continue after recovery from anesthesia, thus leading to anemia. Due to the retro -spective nature of the current study, specifics relating to intraoperative hemorrhage and technique for he -mostasis were not consistently documented. Whereas the available literature reports a 6% to 19% mortality rate in the immediate postoperative period, this pa -per only had a single perioperative death. Much of the available information regarding surgical treatment for feline intracranial meningiomas is from studies performed decades ago. Perhaps the risk of mortal -ity with surgery may be lower than originally reported now that newer surgical approaches and improved technique have been utilized. The most recent paper9 discussing surgical treatment in 121 cats reported an immediate postoperative mortality rate of 6%. A sin -gle cat in the SRT group was noted to have peritreat -ment complications, which included hyperthermia and tachypnea, both of which resolved. In this study, SRT treatment, delivered by the CyberKnife system, required anywhere from 1 to 3 anesthetic events com -pared to the single event for surgery. According to a 2007 paper by Bley et al,29 repeated propofol-asso -ciated anesthesia does not lead to clinically relevant hematologic changes or adverse events in cats under -going short-duration radiotherapy. Four (28.6%) cats in the SRT group and 14 (30.4%) cats in the surgery group had CT- or MRI-confirmed recurrence following initial surgery. According to the literature, a 14% to 21.4% recurrence rate has been noted for surgical treatment1,12,13 and the 1 case that received SRT for an intracranial meningioma did not have documented recurrence.1 Lack of repeat ad -vanced imaging to confirm tumor growth in previous reports may have contributed to a lower than actual tumor recurrence in cats with intracranial meningio -ma. To the authors’ knowledge, the recurrence rate following initial SRT treatment for feline intracranial meningioma is not available. The median time to re -currence for cats receiving surgery as the primary treatment was 1,183 days compared to 315 days in the SRT treatment group ( P = .009; Figure 1). The MST for the 5 of 7 cases that had SRT for subsequent re -currence was 700 days (range, 335 to 1,461 days; 11 to 48 months) after the last treatment, with 2 cases lost to follow-up. We were unable to compare the sig -nificance of overall survival times of patients that had SRT as an adjuvant treatment for recurrence of me -ningioma. This lack of significance could be a result of a type 2 error given the small patient population.This study had several limitations. A definitive histologic diagnosis was obtained in all of the sur -Unauthenticated | Downloaded 12/24/23 09:26 AM UTC 7gically treated cases; however, a presumptive di -agnosis was made in the cats treated with SRT. The accuracy of advanced imaging, using CT or MRI, for diagnosis of primary brain tumors in cats, how -ever, has been long established. In a 2004 study by Troxel et al,20 MRI features of feline intracranial neoplasia were retrospectively reviewed and 96% of tumors were correctly identified as meningioma on the basis of MRI characteristics alone. MRI is the imaging modality of choice for the detection of brain tumors in humans and allows for superior resolution of intracranial lesions compared to CT.30 Six cats were noted to have multiple tumors: 5 in the surgery group and 1 in the SRT group. The effect of multiple tumors on patients included in the study was not investigated; therefore, the in -fluence in the overall clinical picture and survival cannot be elucidated. Additional limitations of this study include its retrospective nature, small case numbers (only 15 patients underwent SRT initial -ly), and lack of follow-up imaging for all patients to determine the impact of SRT on the size of the tumor, determine the progression-free interval, and rule out the possibility of development of sec -ondary delayed radiation effects.In summary, SRT proved to be a safe, alternative treatment for feline patients with intracranial menin -giomas that may have reasons to not undergo sur -gery, such as nonresectable tumors, comorbidities making surgery not an ideal option, or owners who decline surgery. While the MST for the surgery group was significantly longer, at 1,345 days (44 months), the SRT group lived for almost a year, at 339 days (11 months) post-treatment. Due to the low num -bers that received SRT for subsequent recurrence, the evaluation of prolonged survival time and ben -efit was not able to be determined. Future studies with larger case populations evaluating cats with meningiomas treated with SRT alone, as an adjuvant to surgery, or as a treatment for recurrence would be needed to better highlight where SRT might be the most beneficial in the treatment of intracranial meningiomas in cats.AcknowledgmentsNone reported. DisclosuresThe authors have nothing to disclose. No AI-assisted technologies were used in the generation of this manuscript.FundingThe authors have nothing to disclose.

Answer 123

The present study demonstrated the utility of a previously proposed geometric, landmark-guided technique for superficial cervical, axillary, and super -ficial inguinal lymphadenectomies in canine cadavers compared to standard and MB-guided lymphadenec -tomies performed by veterinarians and veterinary students early in their surgical training.10 On the basis of the findings of this study, the null hypothesis was rejected for the ALN and SILN; the findings indicated that LN identification time was reduced for the ALN, tissue trauma was reduced for the ALN and SILN, and subjective difficulty was reduced for the SILN with the landmark-guided technique compared to the stan -dard and MB-guided techniques. However, the null hypothesis could not be rejected for the SCLN, as no significant differences were noted in identification times, TTSs, or subjective difficulty scores between lymphadenectomy techniques for the SCLN.The lack of improvement seen with the LL meth -od for the SCLN was suspected to be secondary to a few factors. First, participants were suspected to be either unfamiliar with or unable to identify the rec -ommended landmarks; all 4 participants who did not identify the SCLN with the LL method had incisions that were too far dorsal and cranial, resulting in the incisions being completely outside of the bounds of the described landmarks. The incorrect positioning of these incisions likely led to excessive tissue dis -section and higher subjective difficulty scores, mak -ing those participants unsuccessful in identifying the SCLN. Second, it is the authors’ impression that, de -spite correct landmark identification and incision ori -entation, the dissection of the SCLN with the patient positioned in dorsal recumbency is more challenging compared to approaching with the patient in lateral recumbency. When the patient is in dorsal recum -bency, the LN tends to fall dorsally due to gravity, resulting in the need to pull the perinodal fat up from a deeper plane. Despite successful identification of the SCLN not being improved with the LL method in the present study, it is possible that with a larger sample size or more experienced surgeons, improve -ments in successful LN identification, T1, and TTS may be observed for the SCLN. Similarly for the SILN dissections, the average T1 for the SILN LL dissec -tion method was approximately half that of the SL method and two-thirds of the average MBL T1. These time reductions could be relevant in a clinical setting, as they would reduce time under general anesthesia and may encourage veterinarians to perform lymph -adenectomies due to their improved efficiency.The 20-minute time limits for LN identification and removal were based on the expected amount of time that a veterinarian might spend searching for an LN before giving up, which was extrapolated from the mean surgical times reported in a previous study.2 Four participants requested to give up before the 20-minute limit, despite eventually identifying those LNs within the allotted time. All requests for early ter -mination were made during the SL and MBL dissec -tions, which could indicate a higher level of frustration with these methods. Similarly, 2 participants in the SL group and 3 participants in the MBL group made second incisions to help with LN identification, but no participants made second incisions in the LL group, even when they were unable to identify the LN. This could indicate a higher level of confidence for some participants with the landmark-guided technique.The use of intraoperative MB injection for LN mapping has been well described within the vet -erinary literature and demonstrated to improve the Table 4 —Comparison of subjective difficulty scores (0 to 100) between the SL, LL, and MBL LN dissections performed in the study described in Table 1. For each LN, dissection method, and dissection period, the mean (95% CI) subjective difficulty scores are reported. Sta -tistical significance was set at P < .05. Subjective difficulty score LN anddissection group Period Mean (95% CI) P valueAxillary SL 1 68 (43–107) .06 MBL 2 62 (37–104) 3 60 (33–108) LL 2 35 (21–59) 3 26 (14–46) Superficial cervical SL 1 47 (29–76) .63 MBL 2 43 (25–75) 3 38 (20–71) LL 2 35 (20–61) 3 28 (15–53) Superficial inguinal SL 1 45 (26–78) .008 MBL 2 28 (15–52) 3 25 (12–50) LL 2 14 (8–27) 3 9 (4–19)Table 5 —Comparison of MB dye uptake perceived by participants during MBL dissections in the study de -scribed in Table 1. The number of cadavers out of 12 with MB uptake that participants visualized within the tissues is listed for each lymphocentrum. MB uptake Subcutaneous Type Skin and/or fascia LNSuperficial cervical 1 5 5Axillary 3 7 4Superficial inguinal 10 8 7Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 11/03/23 06:54 AM UTC8 learning curve and success of sentinel LN identifica -tion in human medicine.6,7,16–19 As a result, MB-guid -ed lymphadenectomy has been considered the gold standard of intraoperative LN identification for veter -inarians without access to more advanced mapping techniques. In the present study, the MBL method did not reduce T1, TTS, or subjective difficulty scores for any LNs. The volume of MB used for injection in the present study (1 mL/lymphocentrum) was much higher than what is described within the current veterinary literature; however, MB uptake within the cadaver lymphatics was very inconsistent and often not appreciated by study participants, which may have contributed to the lack of differences seen be -tween the MBL and SL methods.9,20,21 Additionally, while MB uptake was confirmed to be present in the dermis of all cadavers in the present study, the par -ticipants reported that they did not perceive uptake of MB within all tissues, which is consistent with the known challenge of discerning dye uptake from nor -mal tissue coloration and was likely exacerbated by the fact that none of the participants in the study had previously used intraoperative MB dye for LN mapping.6,17–19,22 Given that poor dye uptake and dif -ficulty discerning dye from surrounding tissues are known challenges of MB dye injection, cadavers in the MBL group were still included in statistical analy -sis even if participants reported that they were un -able to visualize MB in any of the tissues.Despite its use in sentinel LN mapping, MB has been reported to have several disadvantages, includ -ing permanent or prolonged skin staining, increased difficulty with evaluation of surgical margins, inter -ference with pulse oximetry, discoloration of urine, a steep learning curve, poor or incomplete uptake in tissues, difficulty discerning dye uptake from normal tissue coloration, and the need for wider surgical margins when tracing lymphatics.6,9,17–19,22 Given the lack of apparent advantage for LN identification, sur -gical times, tissue trauma, and subjective difficulty observed with the use of MB in the present study, MB guidance for lymphadenectomy outside of sentinel LN mapping may not be worth the associated disad -vantages. The highly variable dye uptake observed in the present study further supports the advantage of using anatomical landmarks as a more reliable meth -od of identification than MB injection.Mean subjective difficulty scores decreased over time for participants regardless of dissection method or LN, which could indicate that participants found the lymphadenectomies to be easier with repetition despite the time between dissection days. Addi -tionally, participants trended toward making longer incisions over time. However, more objective mea -sures indicate that participants’ surgical skills did not improve with repetition; the surgical speed of participants did not improve between SL and later dissection days. For all LNs, T2 was not different be -tween dissection methods, indicating that the dis -section method and day likely had no impact on a participant’s ability to remove an LN. Therefore, the decreased difficulty scores and longer incisions were interpreted as evidence of increased participant confidence levels, despite the fact that their surgical skills and knowledge of LN location did not actually improve throughout the course of the study.Major limitations to this study included the small sample size, variability in scheduling and cadavers, and reliance on participants to read the provided ma -terials. Different lengths of time between dissections may have influenced the quality of dissections or sub -jective difficulty; however, scheduling for the study was limited by the participants’ individual schedules. Freezer storage time for cadavers was variable and could have affected the quality of tissues for dissec -tion or MB uptake, and cadaveric dissections are not completely representative of a clinical setting. The degree to which each participant prepared for the dissection days and each participant’s prior knowl -edge base was beyond the control of the study and may have impacted the success of LN identification. Additionally, participants may have utilized addition -al resources beyond what was provided for them or may not have read the LL surgical guidelines before -hand, which could have affected surgical skill level. Furthermore, MB injection for LN mapping in canine cadavers has been infrequently reported within the veterinary literature and the technique used in this study was developed on the basis of the validated technique and lymphosome map published in a pre -vious study,12 which demonstrated that cadaveric skin can show normal lymphatic contrast agent up -take. Unfortunately, LNs were not transected post -dissection to confirm the presence or absence of MB dye uptake, so the true uptake rates in this study are not known and results are only based on participant perception of dye uptake. For novice surgeons with no prior experience with MB dye for LN mapping, it is possible that discoloration of cadaveric tissues could have made it more challenging to identify dye uptake. Finally, the presence of MB staining within the MBL cadaver dissection sites could have intro -duced bias during the dissection scoring, which was intended to be blinded. Nevertheless, similarities be -tween the MBL and SL groups were still consistent across objective scores (successful LN identification and surgical times) and subjective difficulty.In conclusion, the use of the landmark-guided lymphadenectomy technique reduced time to LN identification for the axillary LN and subjective diffi -culty of superficial inguinal lymphadenectomy com -pared to standard and MB-guided techniques. Ad -ditionally, tissue trauma is more likely to be reduced during axillary and superficial inguinal lymphadenec -tomies when using the landmark-guided technique compared to both the standard and MB-guided tech -niques. Therefore, landmark-guided lymphadenec -tomy methodology may be useful in reducing surgical times, tissue injury, and difficulty in a clinical setting for veterinarians early in their clinical training. Ad -ditionally, this technique is feasible for veterinarians who do not have access to more advanced methods of intraoperative LN mapping, without the disadvan -tages associated with MB injection. Further investi -gation into this topic could include evaluation of the landmark technique using a larger sample size, in a Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 11/03/23 06:54 AM UTC 9clinical setting, or with veterinarians with a different range of experience levels.AcknowledgmentsThe authors would like to thank Dr. W. Alex Fox-Alvarez for his assistance with study design, as well as all participants and volunteers for their participation in the study.JB and NJW contributed to the study conception. JB, NJW, KH, PJR, and CAA contributed to the study design. NJW, JB, CDC, and ECC contributed to data collection. NJW, JB, and PSR contributed to data analysis and interpreta -tion. CHMS and EAM contributed to data interpretation. PSR contributed to statistical analysis. All authors contributed to drafting, revising, and approval of the submitted manuscript.DisclosuresThe authors have nothing to disclose. No AI-assisted technologies were used in the generation of this manuscript.FundingThe authors have nothing to disclose.

Answer 124

This retrospective review of 19 cases demonstrates suc-cessful implementation of partial parasagittal patellec-tomy in a cohort of dogs surgically managed for grade 2or 3 patellar luxation. Furthermore, it details how this isassessed and implemented intraoperatively, as part ofconventional surgery (trochlear trochleoplasty, tibial tu-berosity transposition, and soft-tissue balancing) withoutthe need for modi ﬁcation to surgical approach or equip-ment inventory.Several potential factors have been implicated in theetiology of patellar luxation.21It is accepted that the initialmalformation causes medial (or lateral) quadriceps displace-ment relative to the femur, leading to reduced trochlearsulcus formation and ultimately patellar luxation. Caninetrochlear sulcus formation is reciprocal, achieved throughcontact pressure of the patella over the developing centro-distal femur with a resultant groove formation. Where this isincomplete or absent, a hypoplastic groove forms, beingshallow in depth. Due to the reciprocal relationship andthe ovoid shape of the canine patella in cross-section,incomplete depth may result in a trochlear ridge widthnarrower than the widest part of the patella. This mayexplain why patelloplasty was required in some sti ﬂes wheretrochlear block recession was performed. Additionally,osteophytosis of the patella was infrequently encounteredin the lateral or medial regions upon intraoperative inspec-tion. In these cases, it may therefore be osteophytosis ratherthan true patellar width that prevents recession into thecreated sulcus. However, this still ultimately required inter-vention to allow patellar recession. We suggest that patella –trochlear groove mismatch, like that seen in cats, may be acomponent of the skeletal malformations contributing to theclinical entity of patellar luxation. This is supported by one-ﬁfth of presenting canine patients to our clinic requiringpatellectomy.In all of these cases, we utilized block recession troch-leoplasty to preserve the lateral and medial trochlearridges and provide comparatively increased proximal pa-tellar capture during sti ﬂe extension. Despite subjectiveadequate recession (de ﬁned as allowing 50% or more of thepatella to be recessed in the groove), the width of thepatella prevented successful recession and patellar cap-ture. This has been previously noted in the feline sti ﬂe, andobjectively demonstrated by others,22and it was ourimpression that a similar mismatch occurs in a subset ofcanine patients. Patellar tipping has been described infeline patients where unilateral partial parasagittal patel-lectomy (PPP) is performed,16but this was not encoun-tered in any patient in this series. In each case, a manualﬁnger saw was used to remove the desired amount ofpatella to achieve recession. We avoided the use of anoscillating saw as described by others16to prevent “skat-ing”of the saw blade and iatrogenic damage to the patellarcartilage. Use of a hand saw allowed for accurate andcontrolled bone removal in our hands, and none of thesedogs was noted to have intraoperative damage to thepatellar ligament. Similarly, we removed the smallestamount of patella required to create adequate patellarrecession while leaving the largest possible patellar foot-print for cartilage contact and reduced risk of patellarfracture.16By removing only the minimum tissue re-quired, we also sought to reduce the potential for non-physiological mediolateral movements of the patelladuring weight, anticipating that these could have delete-rious impacts on contact mechanics and cartilage health.In line with previous feline reports, all of our casesexperienced a good to excellent long-term outcome withno major complications.In this case series, the surgical interventions were rela-tively standardized, with all sti ﬂes undergoing block reces-sion trochleoplasty and tibial tuberosity transposition. Wechose to use trochlear block recession due to the previouslydemonstrated improvement in patellar contact mechanicsand proximal capture compared with wedge sulcoplasty,14acommon alternative trochleoplasty technique. With all sti-ﬂes undergoing tibial tuberosity transposition, confoundingvariables were limited when considering clinical outcomesand the effects of patellectomy. Imbrication of the soft tissuesopposite the side of luxation was consistently performed,while adjacent soft tissues were only released when theyprevented patellar reduction. This standardized procedureallows for direct comparison among cases, and use of patel-lectomy in combination with a wedge trochleoplasty, orindeed alternative trochleoplasty techniques, has not beenexplored. Furthermore, in each case trochlear block reces-sion was required due to the shallow nature of the trochlearsulcus as assessed at the time of surgery. Objective preoper-ative measurements where not performed in these cases. Theuse of patellectomy in lieu of trochleoplasty has not beendescribed.Intraoperative minor complications occurred in four sti-ﬂes, exclusively limited to trochlear block fracture withoutassociated complications.17A single complication occurred.postoperatively in this series, with tibial tuberosity avulsiondetected at postoperative radiographic follow-up. This rec-ognized complication was considered minor, given no fur-ther intervention was required to manage the case.9–15Theuse of concurrent patellectomy was considered unlikely tohave led to this complication. However, recession of thepatella into the trochlear sulcus following patellectomymay have altered the forces exerted through the sti ﬂeextensor mechanism, which exceeded either implant orbone resistance.In cases of canine patellar fracture, partial patellectomyhas been reserved as a salvage procedure for irreparablepolar or comminuted fractures,23–25with few cases reportedin the literature.26–28It is reported in human surgery thatpoor outcome is obtained when incomplete reconstruction isachieved for these fractures, and good to excellent outcome isachieved in over 75% of cases where a partial patellectomy isperformed.29It was our concern that, while patellectomyimproved patellar capture and contact mechanics, deleteri-ous effects on the femoropatellar joint may result in the longterm. Every patient achieved an owner-assessed good toexcellent outcome in the long term in our case series, andlimb function was not affected by the condition or surgery asfar as could be assessed. It was also our opinion that contin-ued patellar luxation and poor patellar capture would bemore detrimental to joint health than the required patellec-tomy subsequently performed. This would require furtherstudy to support this supposition.The retrospective nature and subjective outcome assess-ment ofour case series is an inherent limitation for the study. Acustom questionnaire was created for follow-up to providecomparable results between patients, with the questionnairenot validated for this use. Furthermore, this case series isdescriptive and variables have not been identi ﬁed or assessedto guide decision-making or expected outcome in futureclinical cases. Long-term radiographic follow-up was notperformed, and it is recognized that computed tomographyimaging of these sti ﬂes pre- and postsurgery could furtherinform the aims we describe. Progression of secondary osteo-arthritis would be anticipated, as for traditional patellar luxa-tion correction surgery, and may be attributed to any part ofthe intra-articular and periarticular surgery. A case-matchedprospective study would be required in a cohort of dogs todetermine the radiographic impact of patellectomy alongsidetrochlear block recession and tibial tuberosity transposition.The use of patellectomy in these cases was at the discretion ofthe attending surgeon, and objective imaging was not per-formed to con ﬁrm that adequate trochlear block recession hasbeen performed, which could have obviated the need forpatellectomy in these patients. Finally, a larger cross-sectionalstudy would be required to substantiate our theory of patella –trochlear groove width mismatch in a subset of canine patellarluxation patients.In conclusion, we report the short-term outcome resultsobtained in this study with parasagittal partial patellectomyfor augmentationofpatellarluxation correctionwhere patellarrecession cannot be adequately achieved with block recessiontrochleoplasty. However, the effect of patellectomy on caninestiﬂe mechanics and the long-term progression of secondaryosteoarthritis remains incompletely understood.

Answer 125

In this study, we tested the strength and stiffness of singleversus two pin constructs in cadaver limbs for treatmentof TTAF. The mean clinical load to failure in one versustwo pin constructs was 426 and 639 N, respectively.When reported as a normalized percentage, a single pinfor TTAF models withstands approximately 68% of theload to failure and offers 83% of the stiffness as that of atwo-pin fixation. Shahar and Banks-Sills showed thatmedium sized dogs (25 kg) are estimated to generate240 N of force from their quadriceps muscles at a walk.12Forces experienced by the patellar ligament are likelymuch greater during more vigorous activity such as ajump, trot, or run. During the postoperative period,patients' activity is generally limited to short walks asintense activity may lead to implant complications. Boththe one and two-pin fixation techniques withstood forcesgreater than those demonstrated during a walk. Beyondthe strength and stiffness benefits, it is logical that atwo-pin fixation would provide rotational stability of thefractured apophysis that is not offered by a single-pinfixation; however, this has not been formally assessed.5Specific guidelines for TTAF pinning are lacking andlead to discrepancies in KWIAs, pin diameter, and pinnumber.1,3These variables likely result in some degree ofclinical disparity for fixation stiffness and strength. In ourstudy, the same individual placed all pins in a systematicapproach with similar KWIAs. Pin diameters were cho-sen to be the largest diameter that was clinically feasiblebased on the authors ’clinical impression. All pins wereplaced in vertical alignment as this is the authors' prefer-ence and has been shown to demonstrate similar strengthand stiffness when compared to horizontal pin align-ment.13Additional mechanical testing assessing pindiameter and KWIA should each be assessed for theireffects on construct strength and stiffness as some havesuggested that a caudoproximal KWIA may result indecreased pin movement and increased fixation strengthand stiffness.2,11This study was limited by its use of skeletally maturecadaver bones and tissue. Verpaalen and colleaguesdescribed the use of skeletally mature cadaver limbs withspecifically measured osteotomies to model naturallyoccurring TTAF.3This model is limited in its use of skele-tally mature bones to model an injury that primarilyoccurs in immature bone with demonstrably differentmaterial properties.17,18Skeletally immature cadaver limbsfor this model would be extremely difficult to obtain and,with varying stages of endochondral ossification, wouldcreate an insurmountable degree of biologic variabilityamong subjects. Next, the specimens used in our studywere almost entirely female, and specific reproductive sta-tus was not confirmed. Sexual dimorphism and androgenresponsive allometry may account for some variability inbone and tissue biomechanics.19,20The reported stiffnessand loads to failure in our study are likely an underesti-mation of the true values due to the amount of supportivetissue removed for testing and tissue deformation experi-enced during testing. While bone models have been vali-dated and are readily used in biomechanical fracturefixation studies,21these models do not perfectly replicatenatural tissue particularly when replicating the bone-tendon interface. To select for a more homogenous group,only musculoskeletally normal, mature dogs of similarweights and conformation were used in this study. None-theless, some variation of tibia size and shape was appre-ciable. To further mitigate our heterogeneous sample,each animal was treated with both fixation techniques. Byusing this paired study design, each animal served as itsown control and allowed us to report mean stiffness andstrength data as a normalized percentage when comparingFIGURE 5 Box and whisker plots comparing one- and two-pinfixations. Box and whisker plots comparing mean constructstrength (A) and stiffness (B) when comparing tibial tuberosityavulsion fracture models stabilized with one and twointerfragmentary pins placed in vertical alignment.744 WELSH ET AL . 1532950x, 2023, 5, the strength and stiffness of one to two-pin fixations. Afinal limitation is the use of monotonic load to failure inthis study as clinical failure is often a result of cyclic load-ing of an implant. As has been previously suggested,3future studies may also consider ex vivo cyclic loading tobetter replicate what may be occurring during in vivocases of clinical failure.Pin bending and pullout was the cause of ultimatefailure in most cases (82%) with only four failing byepiphyseal fracture (9%) and patellar ligament tearing(9%) in this study. As previously suggested, modificationsin pin application (KWIA and pin diameter selection)may aid to reduce pin bending and pullout. Despiteradiographic evidence for mature physes in the presentstudy, epiphyseal fractures following clinical failureoccurred in two tibias. Pin application near or within theproximal tibial physis may be associated with these fail-ures, and this may be more likely in immature dogscompared to the mature dogs used in this study. It is,therefore, advised to ensure as much distance as possiblefrom the tibial physis when placing the most proximalpin. Finally, incidence of patellar ligament tearing duringbiomechanical testing is reportedly reduced by freezeclamping the tensioning jig to the tissue.3,22Freezeclamping has also been reported to alter natural tissuebiomechanics. Its utility in future ex vivo studies may beequivocal.3,22Moreover, patellar ligament tearing is likelythe result of construct testing and is an unlikely clinicalcomplication to occur.In conclusion, a serial two-pin fixation for TTAF pro-vides superior construct strength and stiffness when com-pared to a single larger diameter pin in this cadavericmodel. These findings may benefit clinicians treatingTTAF, particularly in smaller patients, where implantselection and application may be difficult.AUTHOR CONTRIBUTIONSWelsh PJ, DVM, Nylund AM, DVM, MS, DACVS-SA,Smith LV, MS, PhD, Thompson, DJ, MS, Chen Y, ME,PhD: Study conception and design. Welsh PJ, DVM,Nylund AM, DVM, MS, DACVS-SA, Thompson, DJ, MS,Chen Y, PhD: Data collection and experimental proce-dures. Welsh PJ, DVM, Nylund AM, DVM, MS, DACVS-SA, Smith LV, MS, PhD, Thompson, DJ, MS, Chen Y,ME, PhD: Data analysis. Welsh PJ, DVM: First draft.Welsh PJ, DVM, Nylund AM, DVM, MS, DACVS-SA,Smith LV, MS, PhD, Thompson, DJ, MS, Chen Y, ME,PhD: Comments on draft and final approval. All authorsread and approved the final manuscript.ACKNOWLEDGMENTSThe authors thank Dr Alix McGrath, DVM, the IdahoHumane Society, and staff for their contributions andparticipation in the project. We would also like to thankJeffrey Kensrud, MS and the Washington State UniversitySports Science Laboratory for jig design and constructionand Dr Steven A. Martinez DVM, MS, DACVS,DACVSMR for his support and guidance in projectdevelopment, instrumentation, and clinical insight.FUNDING INFORMATIONAll funding and supplies were provided via MedVetAssociates LLC –Clinical Trials, the Washington StateUniversity School of Mechanic al and Materials Engineering,and the Washington State University ComparativeOrthopedics Laboratory (CORL).CONFLICT OF INTEREST STATEMENTThe authors declare no conflict of interest related to thisreport.DATA AVAILABILITY STATEMENTThe datasets used and/or analyzed during the currentstudy are available from the corresponding author onreasonable request.

Answer 126

Sliding hiatal hernia was successfully treated in the predominantly brachycephalic cohort of dogs in this study using laparoscopic techniques. Further -more, in accordance with our hypothesis, an owner-perceived postoperative improvement/reduction in regurgitation following eating and regurgitation during excitement/increased activity was found. Intraoperative pneumothorax was encountered in 5 (55.6%) dogs and resulted in conversion to open celi -otomy in 2 (22.2%) dogs. Surgeons performing lapa -roscopic treatment of SHH should be aware of this potential intraoperative complication.Intraoperative pneumothorax was the only high-grade complication encountered in the dogs of this study. Intraoperative pneumothorax during laparo -scopic treatment of SHH has been described in the 2 previous reports describing this technique in dogs.10,11In 1 dog of this report, pneumothorax occurred as a result of iatrogenic trauma to the diaphragm from the needle of the suture used to perform hiatal plication. This resulted in conversion to open celiotomy for dia -phragmatic repair and completion of hiatal plication, esophagopexy, and left-sided gastropexy. Caution must be exercised when manipulating the needle dur -ing intracorporeal suturing, and blind movement of the needle should be avoided. Endoscopic guidance should be used to perform any needle manipulation during in -tracorporeal suturing to avoid any iatrogenic trauma to the diaphragm or surrounding abdominal organs. An additional consideration to reduce the risk of iatrogenic trauma by the needle to surrounding structures would be to cut the swaged end of the needle and remove it from the abdomen once suture bites have been taken, prior to tying the knot.In the remaining 4 dogs, pneumothorax was sus -pected to be a result of leakage of insufflated carbon dioxide into the thoracic cavity through suture bites during hiatal plication of the crural muscles of the diaphragm. Bellowing of the diaphragm, indicative of pneumothorax, was not evident in any dog dur -ing laparoscopy despite concerns of pneumothorax expressed by the anesthesia team as hiatal plication progressed. A standard intra-abdominal pressure of 8 mm Hg was used during the initial laparoscopic ap -proach, and the pressure was dropped to 6 mm Hg following port placement. In some dogs of this report, once intraoperative pneumothorax was detected by the anesthesia team, attempts were made to drop intra-abdominal pressure further to reduce the pro -gression/severity of pneumothorax; however, this compromised visualization of the hiatus and could not be maintained. Lift or gasless laparoscopy, alone or in combination with low-level capnoperitoneum, may mitigate the risk of intraoperative pneumothorax and should be evaluated clinically in future cases.17,18For 2 dogs in which intraoperative pneumotho -rax occurred, a thoracic drainage catheter was placed intraoperatively and the pneumothorax evacuated to allow for completion of surgical techniques laparo -scopically. Once the capnoperitoneum for laparosco -py was removed, pneumothorax resolved, providing more evidence to the theory of pneumoperitoneum leakage through the crural muscle suture bites during hiatal plication. In 1 dog with intraoperative pneumo -thorax, conversion to open celiotomy was elected af -ter hiatal plication was performed due to progressive pneumothorax and concerns for cardiovascular de -mise by the anesthesia team. In 1 dog, pneumothorax was diagnosed during postoperative recovery. Tho -racocentesis was promptly performed, and pneumo -thorax was resolved without recurrence. Postopera -tive thoracic radiographs prior to anesthetic recovery in dogs undergoing laparoscopic treatment of SHH, as has been previously suggested,10 may have prevented this complication from occurring.Hiatal plication was performed with intracorpo -real simple interrupted, nonabsorbable sutures in 4 dogs and with a simple continuous pattern with barbed suture in 4 dogs. The change to barbed su -ture was made in an attempt to reduce surgical time related to intracorporeal knot tying and minimize the risk of intraoperative pneumothorax. Meaningful statistical comparison between both hiatal plication techniques and risk of pneumothorax could not be performed due to the small number of dogs in this study. Esophagopexy was performed using the same strand of barbed suture if this method was used for hiatal plication and subjectively reduced surgical Median grade (IQR) Question Preoperative Postoperative P valueDoes your dog have a problem swallowing water? 0 (0–2) 0 (0–0) .09Does your dog have a problem swallowing food? 1 (0–3) 0 (0–0) .057Has the swallowing problem caused your dog to lose weight? 1 (0–2) 0 (0–0) .057Does the swallowing problem occur with canned food? 0 (0–2) 0 (0–0) .18Does the swallowing problem occur with dry kibble? 2.5 (0.5–3) 0 (0–0) .095Does your dog appear painful when eating? 0 (0–0) 0 (0–0) > .99Has your dog’s bark changed in pitch or sound? 0 (0–0) 0 (0–0) .586Does your dog regurgitate after eating? 3 (3–4) 0 (0–1) .008Does your dog regurgitate during increased activity/excitement? 3 (3–4) 1 (0–2) .012Does your dog smack its lips? 1 (0–2) 0 (0–1) .134Table 1 —Pre- and postoperative results of an owner questionnaire10 evaluating 9 dogs undergoing laparoscopic surgery for the treatment of sliding hiatal hernia. Owners were given questions pertaining to their dog and asked for a graded response from 0 to 4, with 0 being clinically normal and 4 being severe. A P value < .005 was considered significant.Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 12/24/23 09:44 AM UTC 5time as introduction of a second strand of suture and locking of the suture line by threading the needle through the welded loop was not required. Further studies are required to evaluate the ideal method for hiatal plication that would minimize surgical time and possible risk of pneumothorax.In this cohort of dogs, left-sided gastropexy was performed using a totally laparoscopic technique in 3 of 7 dogs and with a laparoscopic-assisted technique in 4 of 7 dogs. A totally laparoscopic technique was performed in the initial dogs of this study, while a laparoscopic-assisted technique was elected in sub -sequent dogs. Concerns for intraoperative pneumo -thorax likely influenced the decision for which gastro -pexy technique was selected. In both dogs that had an intraoperative thoracic drainage catheter inserted to resolve pneumothorax, a laparoscopic-assisted gastropexy was performed. This technique was likely selected to reduce the time required for pneumoperi -toneum and allow for resolution of pneumothorax.Five dogs underwent concurrent surgery for BOAS, which resulted in prolonged anesthesia times. While all dogs recovered from anesthesia without complication, prolonged anesthesia time has been associated with an increased risk in complications in brachycephalic dogs.19,20 This finding should be discussed with dog owners if single-staged surgery for BOAS and SHH is being considered. In all brachy -cephalic dogs of this report, staged surgery for BOAS and SHH was recommended to mitigate pos -sible perioperative complications. A recent study21 showed that the owners of brachycephalic dogs un -dergoing conventional multilevel surgery for BOAS perceived a reduction in clinical signs related to gastroesophageal reflux. Based on the results of the study by Mayhew et al,21 dogs with gastroesopha -geal reflux may improve with upper airway surgery alone and may not require surgery for SHH. Further evaluation is required of the role of upper airway sur -gery and its effect on the reduction of clinical signs related to SHH.Postoperative clinical outcomes pertaining to gastroesophageal reflux were evaluated in the dogs of this study using a previously published owner questionnaire.10 Similar to previous reports that used an owner questionnaire to evaluate dogs following laparoscopic treatment of SHH, an improvement in regurgitation following eating and increased activ -ity/excitement was found in the dogs of this report.10 Postoperative esophageal videofluoroscopic swal -lowing studies were not performed of the dogs of this report, representing a limitation of this study. However, a previous study21 reported that videofluo -roscopic evidence of SHH can persist following sur -gery despite clinical improvement.Limitations to this study included its small sample size and retrospective nature, which prevented stan -dardization of preoperative treatment. Additionally, a nonuniform population of dogs was included, which may have compromised postoperative evaluation. A final limitation was that the questionnaire adminis -tered to owners was only administered at the time of postoperative follow-up. Answers provided by owners pertaining to the preoperative clinical status of dogs may have been susceptible to recency bias.In conclusion, laparoscopic treatment of SHH was successful in this cohort of dogs but associated with a high rate of intraoperative pneumothorax. Surgeons performing this procedure should consider this possible intraoperative complication with their anesthesia and recovery team.AcknowledgmentsNone reported.DisclosuresThe authors have nothing to disclose. No AI-assisted technologies were used in the generation of this manuscript.FundingThe authors have nothing to disclose.

Answer 127

Radial development failures owing to genetic or non-genetic factors are classified as embryological formation defects.34 Classifications for radial dysplasia in humans are defined according to the severity of the phenotype.20 Despite the similarities of the phenotype, owing to rare occurrences of radial dysplasia in cats, RH has never been classified in cats. Although bowing of the long bones has been reported in humans with RH, only the bowing of the ulna is evaluated35 for classification. Because the findings on the humerus in cats are also of clinical importance, the status of the humeri in cats should be considered to determine overall severity and classification type. The radiological findings of the two affected kittens according to the classification by Heikel36 suggests the female kitten as having types III and IV dysplasia, whereas the male kitten is suggested as having types II and III for the right and left antebrachium, respectively.Bilgen et al 7Table 1 Echocardiography results of female kitten and sireMeasurementdimensionsLA:Ao (M)Ventricle volumeTeichholz (M)Doppler measurements LA Diam (cm)LA:Ao Ao Diam (cm)IVSd (cm)LVPWd LVIDs (cm)HR (bpm) ESV(Teich) (ml)EF(Teich) (%)FS(Teich) (%)LVIDd (cm)IVSs (cm)LVPWs (cm)EDV(Teich) (ml)SV(Teich) (ml)CO(Teich) (l/min)Mitral valveMV E Vel (cm/s)Sire 1.40 1.46 0.95 0.31 0.43 0.51 168 0.33 89.98 57.14 1.20 0.46 0.54 3.34 3.00 0.497 59.06 Female kitten1.01 1.83 0.55 0.38 0.34 0.58 178 0.47 76.73 42.02 1.01 0.56 0.40 2.11 1.65 0.298 NALA Diam = left atrium diameter; LA:Ao = left atrium-to-aortic ratio (normal measurements: 1.21 ± 0.14); Ao Diam = aortic diameter; IVSd = interventricular septum wall diameters at end-diastole (normal measurements: 0.40 ± 0.03); LVPWd = left ventricular posterior wall (normal measurements: 0.40 ± 0.04); LVIDs = left ventricular internal diameter in end-systole (normal measurements: 1.60 ± 0.10); HR = heart rate (normal measurements: 165 ± 39); bpm = beats per minute; ESV = end systolic volume; EF = ejection fraction; FS = fractional shortening; LVIDd = left ventricular internal dimension in diastole; IVSs = interventricular septal thickness in systole; LVPWs = left ventricular posterior wall thickness in systole; EDV = end-diastolic volume; SV = stroke volume; CO = cardiac output; MV E Vel = mitral valve E velocity; NA = not availablesire also had kinked tails, an autosomal dominant mode of inheritance could be possible if the tail presentation is a result of a heterozygous variant, and the more severe presentation is found in the homozygous kittens.According to the Gene Organizer online tool, the function of CMYA5 is related to cardiac muscles.39 To check the possible effect of the variant in the heart, the RH female kitten’s heart was examined by cardiac ultra-sound. In comparison with other cats at same age, this kitten showed a restrictive cardiomyopathy. The sire was 11 years old, suggesting that the hypertrophic car -diomyopathy (HCM) was probably age-related or the reduced penetrance of gene. No known variants causing HCM in cats were detected within the four cats (data not shown).It is likely that other transcription factors or induced expression of other factors are required for hind forma -tion.40 Although in silico protein function analysis of CMYA5 did not suggest bone formation association and a strong interaction with RH major causative genes, such as SALL4 or TBX5 , CMY5A gene expression could be one of the transcription factors that is necessary for a proper forelimb formation. Like CMYA5, SALL4 and TBX5 genes are both important in heart development and a recent study confirmed TBX5 and CMYA5 interaction during this process.41 CMYA5 is an under-studied striated muscle protein.42 To date, around 40 papers have been published associating CMYA5 with cardiac dyad architecture,42 tibial and limb-girdle muscle distrophies,43 schizo-phrenia44 and even with different types of cancer.45,46 Furthermore a recent study demonstrated CMYA5 as a novel interaction partner of FHL2 in the cardiac myo-cytes,47 which supports the HCM findings of the present study. The position of CMYA5 is adjacent to Z-lines, which precede junctional sarcoplasmic reticulum positioning or transverse tubule formation during cardiac develop-ment,42 whereas TBX5 is required for patterning of the cardiac conduction system and maintenance of mature cardiomyocyte function.48RH cases are associated with more than 30 genes in humans and mice (https://monarchinitiative.org/phe notype/HP:0003974#gene). Fanconi anaemia is especially genetically and clinically heterogenous and RH, together with other congenital abnormalities, is one of the clinical findings. Fanconi anaemia cases are caused by genomic instability based on deficiencies in the DNA repair.49 Upon DNA damage, JMY triggers the p53 response. Via this path, p53-dependent transcription-induced apopto -sis begins.50 Considering the importance of DNA repair and apoptosis mechanisms, JMY cannot be neglected as a second candidate gene. The protein conservation determi-nation for the first 63 amino acids strengthens the impor -tance for the Gln61His missense mutation. Moreover, variations found on this region reported with deleterious effect on Ensembl VEP .31 The A1:145544866 G/T and the 8 Journal of Feline Medicine and Surgery A1:154637756 AAT/- in-frame deletion variations resulted in changes in the protein, but did not segregate concordantly with disease in the pedigree. However, because there are several variations found on this gene, sequencing analysis were performed to confirm variations.The variants in both genes have not been identified previously, confirming the importance of these cats and other such natural knockdown animal models in supporting gene functions. CMYA5 has no documented single gene, pathogenic variants in the clinical variants database (ClinVar; https://www.ncbi.nlm.nih.gov/clinvar). Recently, several causative variants have been determined in diseases such as dwarfism,51 cardiomyopa-thy52 and autosomal dominant ciliopathy53 that represent novel genes for these phenotypes. The identified vari -ant in CMYA5 is suggested to cause a loss of function of the protein, segregates in the pedigree with phenotype, although a limited pedigree, and is a rare variant. This variant is likely pathogenic; however, functional data to support the role of CMYA5 in RH is warranted because its role would be a novel and a new contribution to devel-opmental biology.54Figure 6 Sanger sequencing of cats with radial hemimelia (RH). Homozygous female kitten (IV-01 del/del), heterozygous sire (II-01 WT/del) and unrelated Siamese control cat (WT/WT). Del = presence of the 7 bp deletion in CMYA5. WT = wild-type variant (ie, variant of the reference sequence)Table 2 Candidate DNA variants for radial hemimelia: homozygous in affected kittens and heterozygous in parents with high quality scoresChromosome:position (bp)ReferencealternativeGene name Sequence ontologyEffect Transcript change Protein effectA1:119279957 T/– LOC111560918 Non-coding_exon Other XR_002743256.1:n.1601delA A1:142086375 C/T HMGCR Upstream_gene Unknown XM_003981075.5:c.-139C> T A1:143261775 A/G F2R Missense Missense XM_003981083.5:c.1196A> G p.Tyr399CysA1:143349502 C/T F2RL1 3_prime_UTR Other XM_006927801.4:c.*823C> T A1:143378565 A/C S100Z 5_prime_UTR Other XM_023257685.1:c.-257A> C A1:143383727 G/T S100Z 3_prime_UTR Other XM_023257685.1:c.*592G> T A1:143384113 T/C S100Z 3_prime_UTR Other XM_023257685.1:c.*978T> C A1:145626270 A/G JMY Synonymous Other XM_011284222.3:c.1599A> G p.Gln533=A1:145645611 A/G JMY 3_prime_UTR Other XM_011284222.3:c.*973A> G A1:145646719 TGA/- JMY 3_prime_UTR Other XM_011284222.3:c.*2087_*2089delTGA A1:145659708 T/A LOC111561510 Non-coding_exon Other XR_002744166.1:n.2516A> T A1:145997464 AGACACG/- CMYA5 Frameshift LoF XM_011284243.3:c.9084_9090delAGACACGp.Glu3028Aspfs*3A1:145997473 TG/- CMYA5 Frameshift LoF XM_011284243.3:c.9094_ 9095delGTp.Val3032Lysfs*3A1:146045193 G/C CMYA5 3_prime_UTR Other XM_011284243.3:c.*270G> C B2:11934569 G/A FAM8A1 3_prime_UTR Other XM_019831563.2:c.*3212C> T B4:71658965 C/T GXYLT1 3_prime_UTR Other XM_023256949.1:c.*2939G> A B4:74289208 T/C NELL2 Intron Other XM_023256973.1:c.-32+ 10A> G B4:78207512 C/G LOC109501567 Non-coding_exon Other XR_002159713.2:n.930G> C C1:175836247 G/A FSIP2 Missense Missense XM_023259535.1:c.2586G> A p.Met862IleD3:55279658 C/T DSC1,DSG1 Missense Missense XM_019815118.1:c.111+ 27104G> AXM_011288059.3:c.3218C> Tp.Thr1073MetD3:55969070 C/T LOC111557318 Non-coding_exon Other XR_002737317.1:n.351C> T D3:55970578 G/A MEP1B 5_prime_UTR Other XM_023241859.1:c.-375G> A D3:55970715 G/A MEP1B 5_prime_UTR Other XM_023241859.1:c.-238G> A LoF = loss of functionBilgen et al 9ConclusionsThe findings of the present study suggest an autosomal recessive mode of inheritance with variable expression for radial hemimelia in the Siamese cat family. One dele -tion and several base substitutions in CMYA5 and JMY are proposed as tentative candidate variants for the phenotype, implicating their role in bone development. These genes should be investigated in other cats with RH and evaluated in a larger population to determine allele frequencies in various breeds and populations. Cat breeders, especially those of Siamese cats, could consider genetically testing their cats for these variants to prevent further dissemination within the breed if RH presenta-tions persist.Supplementary material The following file is available as supplementary material: Video 1: Three-dimensional image of the affected female kitten using CT.

Answer 128

The results of this ex vivo study and case report supportthe feasibility of acetabular repair in a minimally invasivefashion with precontoured plates and 3D printingtechniques for fracture repair in dogs. Our technique con-sistently resulted in satisfactory fracture reduction andplate application. Postoperative assessment parameters,including fracture gap, step defect, pelvic angulation, andsciatic nerve injury, were almost entirely within hypothe-sized parameters. In the clinical case, the technique wasexecuted uneventfully, return to weight bearing wasrapid, and full healing was documented in 3 months.Joint incongruity can lead t oa r t i c u l a rc a r t i l a g ew e a rand abnormal intra-articular stresses; precise fracturereduction and restoration of joint congruity for articularfractures is therefore desirable.10In a previous clinical studyof acetabular fracture repair in dogs, a reduction scoringsystem was described where reduction was considered ana-tomic, near anatomic, or nonanatomic when there was<1 mm horizontal displacement, <1 mm vertical displace-ment or ≥1m m < 2m m h o r i z o n t a l d i s p l a c e m e n t ,and≥1m mv e r t i c a ld i s p l a c e m e n to r ≥2m mh o r i z o n t a ld i s -placement, respectively.11Based on these definitions, ana-tomic and near anatomic reduction was achieved with allof our procedures. Postoperative assessments in prior clini-cal studies were conducted on radiographs, whereas CTimages were used in our study.11,12It was previouslyreported in human medicine that CT is likely a preferabletool for postoperative assessment of acetabular fracturerepair as radiographs may be in ferior in characterizing thequality of reduction.13,14It should be noted that insightderived from our study on post-traumatic osteoarthritis isvery limited because the development, severity, and toler-ance to the condition following joint trauma is multifacto-rial and not solely dependent on joint congruency.FIGURE 10 Immediate postoperative radiographs ofacetabular fracture repaired with contoured bone plate. (Lateralview, A; Dorsoventral view, B)FIGURE 11 Three-dimensional reconstructed computedtomographic image of the right acetabular fracture at 8 weekspostoperatively (Dorsal view, A; ventral view, B)842 DALTON ET AL . 1532950x, 2023, 6, Although the exact risk of iatrogenic sciatic nerveinjury due to acetabular fracture repair is unknown, aretrospective study documented poor prognoses in 2 of5 dogs with iatrogenic sciatic nerve injury caused by ace-tabular fracture repair.3We encountered 1 mild instanceof sciatic nerve injury upon dissection. In contrast to ourobservations, sciatic nerve injury was reported in 9 of17 dogs (1 with bilateral fractures) after acetabular frac-ture repair using traditional methods (7/15 with trochan-teric osteotomy and 2/3 with gluteal tenotomy).14Wesuspect that our technique may better protect the sciaticnerve due to the avoidance of direct nerve retraction aswell as protection of the nerve by intact portions of theinternal obturator and gemelli muscles that separate thenerve and the plate. A direct traditional approach, how-ever, does have the advantage of direct visual assessmentof the sciatic nerve and recognition of entrapment byimplants or the fracture itself. Distalization of the greatertrochanter can also be used to address laxity of the coxo-femoral joint, which is not feasible with our technique. Itis possible that sciatic nerve injury sufficient to causeneurological deficits but without grossly evident pathol-ogy (eg, neuropraxia) occurred with our procedures.However, the gross appearance of all evaluated nerves inour study was essentially normal and we did not encoun-ter any elongation that could be observed when largenerves were exposed during standard fracture repair,such as with the radial nerve for humeral fractures.Our technique included 2 incisions which averaged5 cm in length for both caudal and craniolateralapproaches. The traditional approach to the acetabulumin dogs uses a single incision centered over the greatertrochanter, which may be smaller overall than the com-bined incisional length measured in our study;2however,this approach requires either trochanteric osteotomy orgluteal tenotomy, and the span of bone for plate applica-tion is much smaller than that achieved with our tech-nique. With greater experience, acetabular repair may befeasible through smaller incisions than we have docu-mented. We also suspect the regional soft-tissue tensionand subsequent injury generated during retraction wouldbe lower with our technique when compared to thestandard approach; a comparative study between the2 techniques would be required to confirm this possibility.Prolonged surgical and anesthesia time is known toincrease the risk of complications, such as surgical siteinfections. Our pertinent procedure time in the cadavers(caudal and craniolateral approaches, reduction, andrepair) averaged 43 min. Although the total surgical timein the clinical case seemed prolonged (160 min), this casealso underwent sacroiliac luxation repair and treatmentof the physiologic degloving injury. Although we couldnot identify any trends between experience and surgicaltime, the overall procedure time was shortest for our finalcadaver, and we suspect that there is the potential toreduce the operative time reduce further with additionalexperience.We perceived that the use of locking screws stronglyfacilitated the final reduction due to their fixed-angleproperties. In pilot specimens, we noted loss of accept-able reduction when cortical screws were first used tosecure the plates. In a prior ex vivo study of acetabularplating in dogs,15locking screws were not advantageousin maintaining reduction when compared to corticalscrews; however, the osteotomies in this previous studywere stabilized with short acetabular plates (uniLOCKsystem; Synthes). In contrast, the locking compressionplates in this study were contoured along a much widerspan of the hemipelves, which may have been more diffi-cult to contour accurately despite the use of a 3D printedmodel of the pelvis. While locking screws were importantto achieve a suitable reduction, they did not provide rigidfixation, as interfragmentary compression could not beachieved and they were placed far from the fracture site,resulting in a long plate working length. Whether ourconstructs reliably maintain sufficient stability isunknown, and biomechanical studies evaluating our plat-ing technique are warranted.Several modifications to surgical technique could beexplored to improve feasibility and further limit surgicaltrauma. Based on the complexity of pelvic anatomy andprior reports in humans,6,7we postulated that precon-touring plates on 3D-printed bone models was importantto achieve anatomic reduction. In our clinical case, pre-operative planning, including 3D printing, was achievedwithin 48 h of presentation; however, printing time wasshort because the dog was small, and 3D printing mayhave delayed surgical treatment. Furthermore, 3D print-ing is not widely available in veterinary settings. Three-dimensional printing may not be required, as lockingscrews obviate the need for perfect plate contouring, andacetabular MIPO without 3D printing has been per-formed successfully (personal communications, LaurentGuiot). By some definitions,16the technique describedhere may not meet the criteria for MIPO because the frac-ture site was exposed through an arthrotomy. The termis, however, loosely defined, and MIPO might still be asuitable description because we utilized distant incisionsthat were connected by an epiperiosteal tunnel.17How-ever, we have avoided use of this specific term for ourtechnique to eliminate any confusion. We found assess-ment of perfect reduction was difficult with fluoroscopyduring the pilot procedures and thus relied on directobservation of the articular surfaces. Arthroscopic-assisted fracture repair for acetabular fractures is welldescribed in humans18and may be a suitable alternativeDALTON ET AL . 843 1532950x, 2023, 6, to arthrotomy during minimally invasive acetabularrepair.The method used to measure pelvic angulation wasdeveloped for this study to quantify the preservation ofanatomical integrity. Landmarks for reference lines werechosen to prioritize consistency as they seemed easy toidentify for all subjects. While not described previously,we presume that our findings of <5 degrees of sagittaland coronal angulation will be sufficient to produce satis-factory outcomes. Acetabular alignment following frac-ture repair in dogs is not well characterized. In a clinicalstudy, 1 dog was affected by dorsomedial rotation of theacetabular segment, which resulted in luxation of thefemoral head, thus supporting the importance of rotationprevention.12The limitations of this study were due to its cadavericnature, which precluded challenges to fracture repairseen in the live animal, including muscle contraction,fibrosis, and hemorrhage. We also described appositionwith absolute parameters rather than proportional to thesize of the dog (or hip). Thus the step defect data shouldbe interpreted with caution; we elected to report stepdefects in this manner to allow for better comparisons toprevious reports as outlined above. Our simple transverseacetabular fracture model may not be representative ofother fracture configurations, such as oblique or commi-nuted fractures. The favorable outcome of our single clin-ical case should not be considered sufficient evidence todemonstrate the safety and efficacy of this technique.We conclude that minimally invasive acetabularrepair is feasible in dogs and shows promise. The tech-nique should be evaluated further clinically beforeroutine use can be recommended.ACKNOWLEDGMENTSAuthor Contributions: Dalton CL, BS: Responsible fordata acquisition and drafting the manuscript. Kim SE,BVSc, MS, DACVS-SA: Responsible for project conception,study design, data acquisition, data analysis, manuscriptdrafting, reviewing, and editing. Biedrzycki AH, BVSc,PhD, MRCVS, DACVS-LA, DECVS: Responsible for studydesign and for reviewing and editing the manuscript. Mul-len KM, DVM, MS: Responsible for data acquisition and forreviewing and editing the manuscript.The authors would like to thank Hongjia (Duloc) He forassistance with 3D modeling and printing, Cat Monger fortechnical support and assistance with cadavers, and EdwardDeBartolo for his gift, which funded this study.FUNDING INFORMATIONThis study was funded by a gift provided by EdwardDeBartolo to the University of Florida.CONFLICT OF INTERESTThe authors declare no conflicts of interest related to thisreport.

Answer 129

In the feline cadavers studied, the addition of an endo-scope to the traditional TECA-LBO approach was observed to be technically simple and was able to be facilitated through the lateral bulla osteotomy site with -out the need for an additional or expanded approach. A previous study in canine cadavers resulted in the success-ful visualization of 14 notable structures of the middle ear via lateral endoscopic visualization using a 2.7 mm 30° scope;9 in the current study, only 12 structures were able to be directly observed via this approach. Structures unable to be identified in the cat compared with the dog included tympanic bone spicules and the tympanic plexus. Tympanic bone spicules are an inconsistent ana -tomic feature in cats,11 so may not have been present in any of the ears evaluated endoscopically. Another poten -tial cause for the decreased number of visible structures compared with those seen in dogs is the relatively smaller volume of the feline middle ear, as well as the decreased diameter of the bulla osteotomy site in smaller patients. As a result of these size limitations, endoscopic evalua -tion of the middle ear of the feline cadavers was restricted to a 1.9 mm scope; the smaller scope has an inherently narrower image width than the 2.7 mm scope, resulting in a more constrained field of vision. In addition, the cadavers included in this study were utilized in several unrelated studies and had undergone multiple freeze–thaw cycles before the TECA-LBO procedure, resulting in a compromise of the soft tissue structures and a sub -sequent diminished ability to accurately identify these structures, including the tympanic plexus, during endo -scopic evaluation.Despite these limitations, multiple important struc -tures of the tympanic chamber were still able to be con -sistently identified with scope assistance. These included neurovascular structures, such as the chorda tympani, Table 1 Frequency table of procedural outcomes for both traditional-approach and endoscope-assisted total ear canal ablation and lateral bulla osteotomy in feline cadaversN (%)Procedure Successful Not successful Total Odds ratio (95% CI) P value*Endoscope-assisted 12 (50) 1 (50) 13 1.0 (0.1–17.9) 1.0Traditional 12 (50) 1 (50) 13Total 24 (100) 2 (100) 26*Fisher’s exact testTable 2 Frequency table of procedural outcomes for both traditional-approach and endoscope-assisted total ear canal ablation and lateral bulla osteotomy with regard to procedure lateralityN (%)Left ear Right earProcedure Successful Not successful Total Successful Not successful TotalEndoscope-assisted 6 (46.2) 0 6 6 (54.5) 1 (50) 7Traditional 7 (53.8) 0 7 5 (45.5) 1 (50) 6Total 13 (100) 0 13 11 (100) 2 (100) 13Stratum-specific ORs OR = not available* OR = 1.2 (95% CI = 1.0 – 24.5)P value† = 1.0OR Mantel–Haenzel 1.2 (OR 95% CI = 0.1 – 24.5)OR crude 1.0 (OR 95% CI = 0.1 – 17.9)*Odds ratio (OR) could not be calculated†Fisher’s exact testEnright et al 5osseous landmarks, such as the bony promontory, and the incomplete bony septum separating the mesotympanum from the hypotympanum. Rates of neurologic complica -tions during the feline TECA-LBO procedure are particu -larly high compared with those in dogs,12,13 with 42% of patients experiencing postoperative Horner’s syndrome and 58% of patients experiencing postoperative facial nerve paralysis in one study.3 It has been hypothesized that the prevalence of Horner’s syndrome in particular may be largely due to the greater exposure of the tym-panic plexus and post-ganglionic parasympathetic fibers in the feline middle ear that makes these structures more susceptible to iatrogenic damage during aural surgery. The bony promontory is the primary location of the tym -panic plexus;14 therefore, visualization of this structure can allow for greater protection of the plexus during sur -gery, even if the plexus itself is not directly observed and may result in less neurologic trauma.A primary hypothesis of this study was that direct vis -ualization of the bony septum would result in improved success in fully penetrating the septum to gain access to the hypotympanum. In the feline cadaver surgeries, the use of the endoscope to directly visualize the bony septum at the time of surgery did not result in any sig -nificant increase in rates of successful entry into the hypotympanum. However, it is important to note that success rates for penetration through the bony septum were very high in general and notably higher than previ -ously reported success rates.6 There was also no signifi -cant effect of laterality on the success of the procedure, indicating that no additional benefit was derived from the scope, even in procedures performed on the surgeon’s non-dominant side. Access to the hypotympanum is essential for full debridement of the epithelial lining of the tympanic bulla, and in dogs undergoing TECA-LBO for chronic otitis, incomplete ablation of this epithelium poses a risk of continued or recurrent infection of the middle ear, abscessation at the surgery site and formation of acquired cholesteatomas.15,16 In cats, the procedure is less likely to be performed for otitis and more likely to be performed for neoplastic or inflammatory disease, and as a result, the utility of full epithelial debridement is less clear.6 However, previous studies in feline patients have shown that cats with neoplastic or polypoid disease can have secondary low-grade bacterial otitis associated with their disease and can have persistent aural secretions after removal of these growths.13,17,18 Previous reports of feline cholesteatoma19 also suggest that development of the acquired form of this disease may be possible in cats undergoing TECA-LBO without complete epithelial debridement. Most ear canal tumors in cats are malignant and recurrence is possible with incomplete excision,20 and aural polyps are also prone to regrowth, especially in the presence of continued inflammation or infection;21 in both of these situations, full epithelial ablation may be important for removing all traces of disease intraopera -tively. In addition, in those feline patients that do present for primary otitis media, up to 94% may have both middle ear chambers affected,22 making full epithelial ablation as essential in these cats as in their canine counterparts.While the frequency in which entry into the hypotym -panum was achieved in this study is encouraging and implies that access to this chamber can be reasonably accomplished even without scope-assistance, penetration into the hypotympanic chamber does not guarantee effec-tive epithelial ablation. The condition of the soft tissues in the cadavers studied was not conducive to evaluat-ing the epithelial lining of the bulla, and an examination of whether ablation was more effective with or without endoscope-assistance is beyond the scope of this study. However, this may be a worthwhile avenue for future investigation. In addition, other effects on the soft tissue structures were likewise unable to be determined. Human studies have shown that introduction of an endoscope into the relatively small, confined and avascular middle ear results in a rapid increase in the temperature within the bulla by up to 10°C.7 This raises concerns for possible thermal damage to the structures within the middle ear in living patients, particularly the cochlear and neuro-vascular structures. The impact of this thermal damage could potentially negate any possible benefits derived from being able to visualize the neurologic structures of the ear, and further studies to better elucidate the poten -tial benefits and complications of endoscopic evaluation of the middle ear in veterinary patients are indicated.This study was limited by an overall small sample size, which may cause a type II error and obscure significant differences in outcomes with and without the use of an endoscope during the TECA-LBO procedure. In addi-tion, the subjects of this study were decapitated cadaver heads; owing to the lack of the remainder of the cadaver body, surgical positioning was not fully analogous to that which would be exhibited in a live patient. Positioning for the postoperative CT scan was similarly challenging, and recreation of the positioning used for the preoperative imaging could not be perfectly achieved. The difficulties experienced during imaging may have slightly skewed the results of this study, as the cadaver ear that under -went an endoscope-assisted procedure and did not have evidence of entry through the septum on postoperative CT had intraoperative images that clearly showed that a hole had been created in the septum into the hypotym -panum. This calls into question the acuity with which CT can determine whether a defect has been created in the thin bone of the septum. The conflict between intraopera-tive and postoperative findings in this cadaver suggests that there is a possibility of missing septum penetration even with advanced imaging, which may explain why the previous study resulted in lower rates of hypotympanum entry than would be expected.66 Journal of Feline Medicine and Surgery ConclusionsEndoscopic evaluation of the feline middle ear is easily accomplished during the TECA-LBO procedure and allows for visualization of key osseous and neuro-logic structures. While endoscope assistance did not have any effect on the success rate of entry into the hypotym -panum during the procedure, alternative benefits with regards to epithelial ablation and reduced iatrogenic trauma to middle ear structures may exist. Further work to better assess these proposed advantages will be helpful in identifying indications for the use of endoscopy during middle ear surgery in live patients.Acknowledgements The authors thank Dr Natalia Cernicchiaro for the statistics performed in this study.Author note This research was presented as an abstract at the 2022 Society of Veterinary Soft Tissue Surgery (SVSTS) conference in New Orleans, Louisiana, USA.Supplementary material The following file is available as supplementary material: Skulls Unlimited ethical sourcing policy.

Answer 130

While the feasibility of the VITOM-assisted tech -nique for cervical IVDD has been previously reported, to the authors’ knowledge this is the first prospective clinical study that compared video-assisted surgery with a conventional surgical technique in dogs.12 Re-sults from our study showed no significant differences in terms of spinal cord decompression, ventral slot di -mensions, and presence of residual disc material be -tween the 2 surgical techniques. Surgical bleeding and other complications, as well as postoperative neuro -functional outcome, were not statistically different.Ventral slot decompression can be a challenging procedure to perform because the small, narrow, and deeply located surgical field limits direct visualization of the relevant anatomic structures.19 For this reason, a magnification and illuminating system could theoreti -cally make the procedure less challenging due to im -proved visualization of these structures; this was also why we expected better outcomes using the VITOM technique. A possible explanation for the lack of dif -ference between the 2 techniques is the extensive ex -perience of the surgeons performing ventral slot de -compression in this study, regardless of the surgical method used. Therefore, both the conventional and VITOM-assisted surgeries performed by experienced surgeons provided a good outcome. Despite these results and although all surgeons participating in this study were familiar with the conventional ventral slot surgery technique, they all subjectively reported ad -vantages of the VITOM technique, including improved visibility, recognition of the fine tissue details, and bleeding management. This was most likely due to the high-quality magnified images provided by the VITOM system and digital software.20Spinal decompression was considered good to excellent in all dogs, regardless of the surgical tech -nique used. Although overall there was no significant difference in decompression ratio, vertebral body length ratio, and ventral slot width ratio in this study, the agreement of measurements between the 2 radi -ologists tended to be correlated more in the VITOM group than in the conventional surgery group, sug -gesting that the ventral slot dimensions were more consistent in the VITOM group, which could be ex -plained again by visual magnification of the vertebral body drilling site. The discrepancy in measurements between the radiologists in the conventional group impacted the study of the effect of the surgical tech -nique on the vertebral body length ratio, as the ratio was significantly lower in the VITOM group according to one radiologist but not according to the other.In comparison with the OM and endoscope, the VITOM is lightweight, inexpensive, and less cum -bersome.13 This magnification system can be used during the initial dissection because its placement minimally obstructs the surgeon’s direct view of the operative field; moreover, the surgeon can easily ad -just the distance between the scope and the surgical site during the surgery. The focal distance from the telescope lens to the surgical site is approximately 250 mm rather than the 10 to 20 mm that is typical of Figure 3 —Parallel coordinate plots showing the change in neurofunctional status between preoperative (Pre) and postoperative (Post) neurologic examinations in dogs of the conventional surgery and VITOM groups. Neurologic grade is represented on the y-axis.Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 10/20/23 06:53 AM UTC8 endoscopes.13 The surgeon is able to operate while standing straight and upright in a comfortable posi -tion looking at the screen, minimizing surgical stress and operative fatigue by decreasing the need to lean or bend the neck.6The learning curve for surgeons who are experi -enced with laparoscopy or arthroscopy is relatively fast for VITOM-assisted surgery, as perceived by the surgeons of this study.12 Furthermore, it is a tool that is capable of providing optimal teaching conditions since the novice surgeon is able to view the magni -fied images on the monitor during drilling of the ver -tebra and decompression of the spinal cord while not interfering with or obstructing the view of the pri -mary surgeon.10 In addition, a surgical assistant can provide more precise help during the surgery, espe -cially with flushing and aspiration of the surgical site.Some of the previously reported complica -tions, such as seroma, infection, persistent neck pain, worsening of the neurologic status, vertebral instability and reherniation, severe hemorrhage, and death, were not encountered in this study except for the dog in the conventional group that developed discospondylitis 3 weeks postoperatively.Sinus bleeding is a common complication in this surgery. Major bleeding is rarely a life-threatening complication; however, it has been reported in 1.5% to 25% of dogs undergoing ventral slot decompres -sion.5 Rossmeisl et al5 described that mild to mod -erate bleeding occurred 18.8% of the time during ventral corpectomy procedures in dogs. Even if mild to moderate bleeding has no clinical significance, it can negatively affect the surgeon’s visualization of the neural tissues and delay progress of surgery until the bleeding is adequately controlled.14,21 Although there was more sinus bleeding with the use of VITOM than with the conventional technique, the bleeding was controlled in all dogs, most likely because of visibility with magnification. An example of the im -proved bleeding visualization and bleeding control is shown elsewhere (Supplementary Video S1).Occurrence of sinus bleeding was low in the con -ventional surgical group due to exclusion of some dogs from the study, as explained in the Results. This exclusion introduced a bias, which significantly un -derestimated the number and severity of bleeding in dogs in the conventional surgery group. No dog undergoing surgery with the VITOM technique was stopped due to uncontrolled bleeding. Thus, all dogs included in our study had postoperative CT myelog -raphy performed immediately after surgery, allowing for adequate assessment of the spinal cord decom -pression because the residual contrast medium was visible in all dogs.22 No complications secondary to CT myelography have been reported in this study. Another limitation was the use CT myelography in -stead of MRI, which underestimated the presence of noncalcified disc material and even hemorrhage.In dogs with cervical IVDD, residual herniated disc material has been reported to be between 57% and 77% after ventral slot decompression with postoperative CT myelography.12,14,23 Although residual disc material was present in both groups, all dogs had improvement of their neurologic status. Residual disc material is not associated with a poor functional outcome.On the basis of the low OR, the VITOM technique seemed to increase the likelihood of achieving a bet -ter postoperative neurologic grade compared to the conventional surgery technique. However, statisti -cal significance was not achieved, likely because of the lack of power due to the small number of dogs enrolled in this study. A larger study is warranted to investigate these results.Although all surgeons were highly experienced as a specialist or senior resident, a possible limitation of this study was that the surgeries were performed by different surgeons. Another limitation was that the dogs were classified in each group in a nonran -dom way on the basis of the availability of the VITOM system. For these reasons, future prospective stud -ies with a larger sample size and improved controls are needed (same surgeon, comparisons of IVDE site, bleedings, and use of an MRI).In conclusion, no differences were found be -tween the 2 groups in terms of spinal cord decom -pression, ventral slot dimensions, residual materials, surgical bleeding and complications, and postopera -tive neurofunctional outcome. Despite this, VITOM assistance subjectively provided good anatomic vi -sualization, allowing for superior bleeding control, more regular ventral slot dimension, and possibly better neurofunctional recovery, although further larger studies are required to confirm these results.AcknowledgmentsNo third-party funding or support was received in connec -tion with this study or the writing or publication of the manuscript. The authors declare that there were no conflicts of interest.

Answer 131

Stenotic nares is an uncommon cause of respi -ratory distress in cats, occurring primarily in Persian and other exotic brachycephalic cat breeds.1–4 Unlike dogs, stenotic nares in cats is not usually associated with concurrent soft palate, laryngeal, or tracheal abnormalities and appears to be the predominant primary abnormality causing clinical respiratory signs.2,4,7 None of the cats in this present study had elongation of the soft palate; each had normal laryn -geal function on oral examination.The smaller anatomic features of the feline nares make brachycephalic cats particularly vulnerable to upper airway distress due to Poiseulle’s law, that de -fines a 16-fold increase to air flow resistance with a 50% reduction in airway radius.10,11 There are notable anatomic differences of the skull and nasal cavity of brachycephalic cats compared to the general cat pop -ulation.12 One study on brachycephalic cats utilized CT and endoscopic examination to assess the nares, nasal vestibule, and the turbinates.7 Narrowing of the nares and nasal vestibule were noted. Computed to -mography noted radiologic evidence of aberrant tur -binates rostrally, but without rhinoscopic evidence of visibly obstructive rostral aberrant nasal turbinates (obstruction of the rostral nasal passages). Only 1 of 19 cats had caudal aberrant nasal turbinates both on CT and rostral/caudal rhinoscopic examination.7 This latter finding was in contrast to a study reporting a 21% prevalence in another feline brachycephalic re -port.13 This present paper also reports on our clinical finding that the elevated skin, rostral to the sulcus, is a contributing factor in feline brachycephalic stenotic nares: the “Labial Pull-Down” portion of the proce -dure eliminates this cutaneous prominence.Other respiratory signs may be associated with brachycephalic cats including sneezing, coughing, nasal discharge, open mouth breathing, snoring, up -per respiratory noise, and severe dyspnea. Changes of the upper respiratory tract in brachycephalic cats can contribute to problematic sleeping and activity intoler -ance.7 Brachycephaly in the cat can also be associated with other gastrointestinal disorders including hyper -salivation, halitosis, difficulty chewing, and messy eat -ing/drinking.14 In our study, except for increased inspi -ratory difficulties and occasional sniffling, there were no other signs reported by the owners.Despite the intranasal changes reported in brachy -cephalic cats, surgical correction of stenotic nares does provide notable improvement in breathing for brachycephalic cats as well as their cardiopulmonary and activity-related parameters.5–8 Following ala ves -tibuloplasty in one series of brachycephalic cats, visual improvement of the nares and nasal vestibule was evi -dent: this was also noted in our present study.7 Single pedicle advancement of the nasal mucosa also was re -ported to provide a good outcome in brachycephalic cats.6 However, the flaps are small and delicate: surgi -cal loupes, ophthalmic instrumentation, and fine 5-0 suture material are required. Other ala vestibuloplasty procedures include the partial resection of the axial alar wing (ala nasi) and alar fold (vestibulum nasi) using a cutting instrument or laser. The cutaneous punches used to enlarge the nares in this study avoid the need to incise the sensitive vascular tissue of the nares, alter -ing the appearance of the cat’s external nose.The width of the cutaneous surgical defects created may vary slightly, based on the size of the cat and its facial conformation. In general, a 4- to 5-mm-wide skin resection allows for sufficient skin tension to elevate the elastic alar folds and depress the skin rostral to the sul -cus. The 4-mm biopsy punch option is technically easier to perform than the use of a No. 11 scalpel blade, espe -cially in smaller cats. The firmer underlying tissue sup -port facilitates the insertion and cutting action of the bi -opsy punch. Wider resection is possible if 2 skin punches are performed immediately adjacent to, or slightly over -lap one another; this was not necessary in these cats.The skin dorsolateral to the alar folds is relatively inelastic and is attached to the underlying fascia. As a result, the possibility of the skin stretching over time, negating the surgical gains in alar elevation, was not noted in the long-term follow-up of each cat. The own -ers were pleased with the results of the surgery, noting that nasal breathing was notably improved without no alteration in the size of the nares postoperatively.The combined use of the “Alar Fold Lift-Up” and “Sulcus Pull Down” Techniques in this study simul -taneously addresses both anatomic areas that com -promise the opening of each nostril. As noted, the skin is easily assessable and the surgery is simple to execute with minimal instrumentation while avoiding the need to incise the sensitive vascular tissue of the nares. Cats can be discharged the same day of this minor skin procedure.AcknowledgmentsNo internal or external funding was received in conjunc -tion with this publication. The authors declare that there were no conflicts of interest.The authors thank Ms. Sandra Durant for the artwork in -cluded in this report.Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 08/30/23 11:59 AM UTC 5

Answer 132

In this study, Pekingese were presented with various age, rate of onset, severity of neurologic dys -function, and degree of paraspinal pain. Pekingese is a CD-breed dog with early chondroid metaplasia and degeneration of the nucleus pulposus with ul -timate failure of the intervertebral disc unit.1,21 The survey spinal radiographic findings of intervertebral disc calcification were consistent with degenerative discs due to chondroid metaplasia.1Each spinal segment consists of an intervertebral disc and paired APs. Each component influences the other two, with abnormality or degenerative chang -es in a single joint affecting the biomechanics of the whole complex.22 The shapes of thoracolumbar APs vary between different vertebrae, and a morphologic analysis of the canine spine has suggested there is a high prevalence of AP abnormality in neurologically normal small-breed dogs.23 Caudal AP abnormality has been reported to be a frequent finding in neurologically normal Pugs.24 APs contribute up to 30% of the stability of the vertebral column in the intact spine of dogs.9–11 Figure 3 —Dog 8. A—Neutral myelogram showing mild attenuation of the dorsal contrast column and dorsal deviation of the ventral contrast column at T13–L1. Spi -nal cord height was 4.0 mm. B—Dynamic myelogram on dorsal extension showing marked attenuation of the dorsal contrast column and dorsal deviation of the ventral contrast column at T13–L1. Spinal cord height at T13–L1 of 3.0 mm (25% reduction) was noted. C—Postoperative radiograph showing 4 positively thread -ed profile pins inserted into the vertebral bodies of T13 and L1. CdAP Compression Dynamic compression and poststress VertebralDog abnormality in neutral position spinal cord height reduction (%) stabilization1 None None T12–T13 (ext: 24.4%) T12-132 None T11–T12, T12–T13, T13–L1, T11–T12 (ext: 5.0%), T12–T13 (ext: 7.3%), T11-12, T12-13, T13-L1 L1–L2, L2–L3 T13–L1 (ext: 14.7%)3 None T12–T13, T13–L1, L1–L2, L2–L3, T13–L1 (ext: 23.5%), L1–L2 T13-L1, L1-2 L3–L4 (ext and flex: 12.8%)4 T10, T11, T12 T12–T13 T12–T13 (flex: 8.6%) T12-135 None T12–T13, T13–L1 T13–L1 (ext: 22.0%) T13-L1, L1-26 None T12–T13 T12–T13 (ext: 20.0%) T12-137 L2 T9–T10, T13–L1, L1–L2, L2–L3, L3–L4 L1–L2 (flex: 11.4%), L2–L3 (flex: 5.3%) L1-2, L2-38 T12 T9–T10, T13–L1 T13–L1 (ext: 25.0%) T13-L19 None L1–L2 L1–L2 (ext: 21.6%) L1-210 T12, T13 T12–T13, T13–L1 T13–L1 (ext: 6.6%) T13-L111 T12, T13 T12–T13, T13–L1, L1–L2, L2–L3 T12–T13 (ext: 15.0%), T13–L1 (ext: 5.7%), T12-13, T13-L1, L1-2 L1–L2 (ext: 25.0%)ext = Extension. flex = Flexion. Table 1 —Summary for location where caudal articular process (CdAP) abnormality (hypoplasia or aplasia), compression in neutral position and dynamic compression, and vertebral stabilization were noted.Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 10/20/23 06:54 AM UTC6 Abnormal shape of the AP is likely to cause instability in quality and/or low-grade instability. With vertebral instability, movement can be abnormal in quality (ab -normal coupling patterns) and/or quantity (increased motion).6 This low-grade instability is likely to cause chronic micromotion.6 Congenital or degenerative changes of other vertebral structures are responsible for early intervertebral disc degeneration and vertebral instabilities in small-breed dogs. The degenerative joint disease of the AP unassociated with the AP abnormal -ity seen in 3 Pekingese is likely due to the chronic mi -cromotion by the degenerated intervertebral discs or compromised stability of other vertebral structures. Chronic instability results in fibrous ligamentous hyper -trophy of the annulus fibrosus of the disc or dorsal lon -gitudinal ligament. This osteoligamentary hypertrophy has been reported as the cause of the dynamic com -pressive lesion in caudal cervical spondylomyelopathy and lumbosacral instability.25 These changes eventually lead to a constrictive lesion.13 The spondylosis defor -mans were suggestive of a compensatory mechanism for vertebral instability.26In the present study, caudal AP anomalies were identified in 5 Pekingese. Although AP anomalies have been suggested as a cause of spinal cord injury in Pugs, the presence of an abnormality does not always cor -relate with the underlying vertebral instability or spinal cord injury.27 In a study17 of 14 Pugs that underwent decompression and stabilization for lesions in prox -imity to caudal AP anomalies, 6 lesions were at sites with no caudal AP anomalies. In a recent study18 of 7 Pugs with vertebral instability associated with various degrees of AP abnormality, a dynamic study demon -strated that 2 of 9 dynamic compressive lesions were at sites with no AP abnormality. These reports suggest that AP aplasia/hypoplasia is not the solitary factor of vertebral instability. Subtle anatomical abnormalities of the AP and other vertebral structures can potentially compromise vertebral stability. Although radiographs and CT images demonstrate vertebral or AP anomalies as well as secondary osteoarthritic changes indicative of vertebral instability, they are not definitive enough to fully characterize concurrent vertebral instability.14,27Dynamic myelographic study was useful in demon -strating the single or multiple dynamic lesion responsible for the spinal cord injury. Dynamic myelographic study demonstrated that 17 compressive lesions in neutral po -sition reduced the spinal cord height in stressed position (IQR, 6.8 to 21.2). Spinal cord height reduction was iden -tified at a site with no compression in the neutral position, suggesting such lesions do not preclude the possibility of a dynamic lesion.8 Of these 17 dynamic lesions, the association with AP anomalies was identified in 5 sites. Similar to Pug dogs with an AP abnormality, the dynamic lesion may not correlate to the site with an AP abnormal -ity. The presence of intact AP on radiographic/CT evalua -tion does not preclude the possibility of a dynamic lesion in Pekingese dogs. Therefore, the primary lesion respon -sible for the spinal cord injury and the decision to perform stabilization and its extension needs to be made through a dynamic study. As compared to the kinematic MRI, which is reported to require considerable amount of time and intensive labor, dynamic myelographic study is easily performed. Dynamic myelographic study requires only 1 second for the patient to be placed in extension or flexion position when radiographs are taken.18,28 The force ap -plied to demonstrate the dynamic lesion can be adjusted to avoid the iatrogenic spinal cord injury. In the present study, dynamic myelographic study was performed with extreme caution. If lesser force did not demonstrate the dynamic lesion initially, greater force was applied for the second dynamic study.Vertebral instability was confirmed by intraopera -tive direct spinal manipulation in all dogs. The caudal 4 thoracic vertebrae represent a transitional portion of the spine. The orientations of the articular surface of the cra -nial and caudal APs are different.29 The dorsolateral and mediolateral range of motion are different in these spinal segments. They are also altered by age, chronicity of the vertebral instability, or amount of osteoligamentary hy -pertrophy or spondylosis deformans. When vertebral in -stability was inconclusive by spinal manipulation, it was subjectively compared with the stability of the adjacent vertebral segments. This method of evaluation needs to be standardized by a biomechanical study.The surgical decompressive procedure confirmed that all but 1 Pekingese in the present study had com -pressive lesions consisting of fibrous ligamentous hy -pertrophy of the annulus fibrosus of the disc or dorsal longitudinal ligament, which was similar to Pug dogs with constrictive myelopathy.18 Although thoracolumbar hemilaminectomy without stabilization is a standard sur -gical procedure for dogs with IVDE, it may not be safe for Pekingese with compromised vertebral stability.18 A study to evaluate the proportion of Pekingese that require vertebral stabilization would be necessary. Unilateral ver -tebral stabilization using pin and PMMA is an easy and ef -fective method with limited intraoperative complications. Follow-up radiographic evaluation confirmed that stabi -lization was maintained in all dogs. All dogs improved or maintained the ability to ambulate at the last follow-up evaluation (median, 16 months; IQR, 3 to 32 months).A potential disadvantage of stabilization of 1 or more vertebral motion units is adjacent segment dis -ease.30 Dynamic stresses are redirected to adjacent intervertebral discs, and a domino effect may occur whereby these aberrant forces precipitate disc disease.31 One dog (dog 9) had a second vertebral instability of 2 sites with AP anomalies adjacent to the previous site 3 months postoperatively. In this dog, the initial dynamic study did not demonstrate a dynamic lesion that devel -oped after the initial surgery. Adjacent segment disease is a likely cause of second vertebral instability.The limitations of this study included its retrospec -tive nature, small sample size, and lack of control cases. Not all cases were evaluated by CT or MRI imaging. De -tailed CT evaluations have not been validated for subtle anatomical abnormalities of the AP and other vertebral structures that potentially compromise vertebral sta -bility. The degrees of AP abnormality or degenerative change and their causative effect on vertebral instability need to be evaluated in a future study.32 The use of MRI may have provided more detailed and additional infor -mation of the spinal cord lesion, concurrent spinal cord damage, and prognosis.28 The spinal stability was sub -jectively assessed by intraoperative spinal manipulation, Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 10/20/23 06:54 AM UTC 7and this potentially risk-involved measurement needs to be standardized.33Vertebral instability associated with or without AP ab -normality is a potential cause of thoracolumbar spinal cord injury in Pekingese. Dynamic myelographic studies and/or intraoperative manipulation of the spine demonstrated the vertebral instability. Spinal cord decompression and verte -bral stabilization were effective for these conditions, result -ing in neurologic improvement in most dogs.AcknowledgmentsThe authors declare no conflicts of interest related to this report.

Answer 133

The design of this study allowed for a controlled comparisonof six proximal tibial osteotomies used for correction of eTPAin the dog, speci ﬁcally evaluating their impact on sagittalplane tibial alignment when correcting to a target TPA foreach procedure./C3/C3/C3The results con ﬁrm that the TPLO/CCWOhas the least impact on tibial geometry, while the coCBLO,CCWO, and iCCWO have the greatest impact. Additionally, apositive correlation was demonstrated between TPA and themagnitude of alterations to tibial alignment, speci ﬁcallyTLAS, dTTS and cTTS. All virtual proximal tibial osteotomiesachieved a post-simulation TPA within 0.5 degree of theestablished targets. Virtual corrections reduced error thatwould be introduced from repeated inter- or intra-observermeasurements, transitioning between radiographic andTable 3 TPA and wedge angle. Summarized results (mean /C6standard deviation) for pre-simulationTPA and wedge angle based onostectomy and TPA groupPre-simulationTPA (degree)CCWO mCCWO iCCWO niCCWO TPLO /CCWOcoCBLO p-ValueModerateTPA31.9/C61.7Wedge angle(degree)31.1/C61.9a30.6/C62.8a31.1/C62.1a31.1/C62.1a0/C60b0/C60b<0.001Severe TPA 38.2/C63.3Wedge angle(degree)37.5/C63.1a37.7/C63.5a37.8/C63.6a37.8/C63.4a12.2/C62.3b12.2/C62.4b<0.001Extreme TPA 50.4/C63.3Wedge angle(degree)50.7/C63.4a51.7/C63.2a51.6/C63.6a52.1/C63.3a17.9/C63.8b19.1/C63.9c<0.001Abbreviation: TPA, Tibial plateau angle.Note: Wedge angles within each row are signi ﬁcantly different ( p<0.05) if they do not share the same superscript letter.Table 4 Data summary for all TPA groups. Mean (95% CI) radiographic tibial morphology changes after virtual proximal tibialosteotomy for excessive tibial plateau angle in 30 tibiasCCWO (A) mCCWO (B) iCCWO (C) niCCWO (D) TPLO/CCWO (E) coCBLO (F)TLAS(degree)4.6 (4.3, 4.9)d,E,F4.9 (4.6, 5.2)E,F4.9 (4.6, 5.2)E,F5.2 (4.9, 5.5)a,E,F1.4 (1.1, 1.7)A,B,C,D,F6.5 (6.2, 6.8)A,B,C,D,EcTTS (mm) 3.8 (2.8, 4.8)b,D,F5.6 (4.7, 6.6)a,e,F4.9 (3.9, 5.8)F6.2 (5.3, 7.2)A,E,F3.6 (2.7, 4.6)b,D,F13.1(12.2, 14.1)A,B,C,D,EdTTS (mm) 29.5(28.1, 30.9)B,C,D,E,F21.2(19.8, 22.5)A,C,E27.2(25.8, 28.5)A,B,D,E,F20.1(18.8, 21.5)A,C,E6.8(5.5, 8.2)A,B,C,D,F19.6(18.3, 21.0)A,C,EdTTS /Tibial length0.14(0.14, 0.15)B,C,D,E,F0.10(0.10, 0.11)A,C,E,f0.13(0.13, 0.14)A,B,D,E,F0.10(0.09, 0.10)A,C,E0.03(0.03, 0.04)A,B,C,D,F0.09(0.09, 0.10)A,b,C,EOsteotomyoverlap (%)70.3(67.3, 73.3)B,C,E,f86.6(83.6, 89.6)A,C,D,F100.0(97.0, 103.0)A,B,D,F,E67.8(64.8, 70.8)B,C,E,F87.4(84.4, 90.4)A,C,D,F76.9(73.9, 79.9)a,B,C,D,ETibialshortening(mm)6.5(5.9, 7.0)B,C,D,E,F/C01.8(/C02.4,/C01.2)A,C,d,E4.4(3.9, 5.0)A,B,D,E,F/C03.0(/C03.6,/C02.4)A,b,C,E0.4(/C00.2, 1.0)A,B,C,D,F/C02.5(/C03.1,/C01.9)A,C,EAbbreviations: CI, con ﬁdence interval; cTTS, cranial tibial tuberosi ty shift; dTTS, distal tibial tuberosity shift; TLAS, tibial long axis shift; TPA, tibialplateau angle.Note: Lowercase superscript let ters indicate virtual correct ions with means that are signi ﬁcantly different at p<0.05.Capitalized letters indicate means that are signi ﬁcantly different at p<0.001.Bold values indicate virtual corrections with means that are signi ﬁcantly different from all other virtual corrections..Table 5 Data summary for moderate TPA group. Mean (95% CI) radiographic tibial morphology changes after virtual proximaltibial osteotomy for 10 tibias with moderate tibial plateau angles of 29 to 34 degreesCCWO (A) mCCWO (B) iCCWO (C) niCCWO (D) TPLO (E) CBLO (F)TLAS(degree)4.2 (3.8, 4.6)E,f4.0 (3.6, 4.4)E,F4.1 (3.7, 4.5)E,F4.1 (3.7, 4.5)E,F0.0(-0.4, 0.4)A,B,C,D,F4.8(4.4, 5.2)a,B,C,D,EcTTS (mm) 3.3 (2.2, 4.4)E,F3.5 (2.4, 4.6)E,F3.2 (2.1, 4.3)E,F3.4 (2.3, 4.5)E,F0.0(/C01.1, 1.1)A,B,C,D,F8.9(7.8, 10.0)A,B,C,D,EdTTS (mm) 22.3(20.6, 24.0)B,D,E,F15.9(14.2, 17.6)A,C,E,F21.4(19.7, 23.1)B,D,E,F15.4(13.8, 17.1)A,C,E,F0.0(/C01.7, 1.7)A,B,C,D,F12.5(10.9, 14.2)A,B,C,D,EOsteotomyoverlap (%)81.1(79.6, 82.6)C,D,E82.7(81.2, 84.2)C,D,E,f100.0(98.5, 101.5)A,B,D,E,F67.3(65.8, 68.7)A,B,C,F69.0(67.5, 70.4)A,B,C,F79.2(77.7, 80.7)b,C,D,ETibialshortening(mm)4.1(3.6, 4.6)B,D,E,F/C02.0(/C02.5,/C01.5)A,C,E,F3.4(2.9, 3.9)B,D,E,F/C02.7(/C03.2,/C02.2)A,C,E,f/C00.1(/C00.6, 0.4)A,B,C,D,F/C03.9(/C04.4,/C03.4)A,B,C,d,ETibialshortening/TLAH0.02(0.02, 0.02)B,c,D,E,F/C00.01(/C00.01,/C00.01)A,C,d,E,F0.02(0.01, 0.02)a,B,D,E,F/C00.01(/C00.01,/C00.01)A,b,C,E,F0.00(0.00, 0.00)A,B,C,D,F/C00.02(/C00.02,/C00.02)A,B,C,D,EAbbreviations: CI, con ﬁdence interval; cTTS, cranial tibial tuberosi ty shift; dTTS, distal tibial tuberosity shift; TLAS, tibial long axis shift; TPA, tibialplateau angle.Note: Lowercase superscript letters indicate virtual corrections with means that are signi ﬁcantly different at p<0.05.Capitalized letters indicate means that are signi ﬁcantly different at p<0.001.Bold values indicate virtual corrections with means that are signi ﬁcantly different from all other virtual corrections.Table 6 Data summary for severe TPA group. Mean (95% CI) radiographic tibial morphology changes after virtual proximal tibialosteotomy for 10 tibias with severe tibial plateau angles of 34.1 to 44 degreesCCWO (A) mCCWO (B) iCCWO (C) niCCWO (D) TPLO/CCWO (E) coCBLO (F)TLAS(degree)4.4 (3.9, 4.9)E,F4.6 (4.1, 5.1)E,F4.5 (4.0, 5.0)E,F4.7 (4.2, 5.2)E,F1.5(1.0, 2.0)A,B,C,D,F6.0(5.5, 6.5)A,B,C,D,EcTTS (mm) 3.2 (2.0, 4.3)F4.6 (3.4, 5.7)F3.8 (2.6, 5.0)F4.8 (3.7, 6.0)F3.1 (2.0, 4.3)F11.5(10.4, 12.7)A,B,C,D,EdTTS (mm) 28.0(24.8, 31.2)B,D,E,F20.3(17.1, 23.5)A,C,E26.8(23.6, 30.0)B,D,E,F19.4(16.1, 22.6)A,C,E8.7(5.5, 11.9)A,B,C,D,F19.5(16.3, 22.7)A,C,EOsteotomyoverlap (%)73.7(70.4, 77.0)B,C,d,E,f86.1(82.8, 89.4)A,C,D,E100.0(96.7, 103.3)A,B,D,F67.3(64.1, 70.6)a,B,C,E,F98.3(95.0, 101.6)A,B,D,F80.3(77.0, 83.6)a,C,D,ETibialshortening(mm)5.9(5.1, 6.7)B,D,E,F/C01.9(/C02.7,/C01.1)A,C,E4.8(4.0, 5.6)B,D,E,F/C02.8(/C03.6,/C02.1)A,C,E0.6(/C00.2, 1.4)A,B,C,D,F/C01.6(/C02.4,/C00.9)A,C,ETibialshortening/TLAH0.03(0.02, 0.03)B,c,D,E,F/C00.01(/C00.01,/C00.01)A,C,d,E0.02(0.02, 0.03)a,B,D,E,F/C00.01(/C00.02,/C00.01)A,b,C,E,f0.00(0.00, 0.01)A,B,C,D,F/C00.01(/C00.01, 0.00)A,C,d,EAbbreviations: CI, con ﬁdence interval; cTTS, cranial tibial tuberosi ty shift; dTTS, distal tibial tuberosity shift; TLAS, tibial long axis shift; TPA, tibialplateau angle.Note: Lowercase superscript letters indicate virtual corrections with means that are signi ﬁcantly different at p<0.05.Capitalized letters indicate means that are signi ﬁcantly different at p<0.001.Bold values indicate virtual corrections with means that are signi ﬁcantly different from all other virtual corrections.Table 7 Data summary for extreme TPA group. Mean (95% CI) radiographic tibial morphology changes after virtual proximal tibialosteotomy for 10 tibias with extreme tibial plateau angles of >44 degreesCCWO (A) mCCWO (B) iCCWO (C) niCCWO (D) TPLO/CCWO (E) coCBLO (F)TLAS (degree) 5.3 (4.7, 5.9)d,E,F6.2 (5.6, 6.9)E,F6.1 (5.5, 6.7)E,F6.7 (6.1, 7.3)a,E,F2.6 (2.0, 3.3)A,B,C,D,F8.7 (8.1, 9.3)A,B,C,D,EcTTS (mm) 4.9 (2.5, 7.3)b,D,F8.9 (6.4, 11.3)a,F7.6 (5.2, 10.0)F10.4 (8.0, 12.8)A,F7.8 (5.4, 10.2)F19.0 (16.6, 21.4)A,B,C,D,EdTTS (mm) 38.2(35.9, 40.5)B,C,D,E,F27.2(24.9, 29.6)A,C,D,E33.3(30.9, 35.6)A,B,D,E,F25.5(23.2, 27.9)A,B,C,E11.7(9.4, 14.1)A,B,C,D,F26.9(24.6, 29.2)A,C,EOsteotomyoverlap (%)56.1(53.1, 59.2)B,C,D,E,F91.0(88.0, 94.0)A,C,D,F100.0(97.0, 103.0)A,B,D,F68.8(65.7, 71.8)A,B,C,E95.0(92.0, 98.0)A,D,F71.3(68.2, 74.3)A,B,C,ETibialshortening(mm)9.4(8.0, 10.7)B,C,D,E,F/C01.6(/C03.0,/C00.2)A,C,d,e5.1(3.8, 6.5)A,B,D,E,F/C03.4(/C04.8,/C02.0)A,b,C,E0.5(/C00.8, 1.9)A,b,C,D,F/C02.0(/C03.4,/C00.6)A,C,EAbbreviations: CI, con ﬁdence interval; cTTS, cranial tibial tuberosi ty shift; dTTS, distal tibial tuberosity shift; TLAS, tibial long axis shift; TPA, tibialplateau angle.Note: Lowercase superscript letters indicate virtual corrections with means that are signi ﬁcantly different at p<0.05.Capitalized letters indicate means that are signi ﬁcantly different at p<0.001.Bold values indicate virtual corrections with means that are signi ﬁcantly different from all other virtual corrections..intraoperative measuring, or varied radiographic position-ing, as seen in a clinical setting.Various methods of determining the ideal wedge anglehave been proposed; however, they have led to inconsistentresults when applied clinically.16,20,22,23Theﬁndings fromthis study demonstrate that the wedge angle needed toobtain a target TPA of approximately 5 degrees was typicallywithin 1 degree of the pre-simulation TPA for CCWO,mCCWO, iCCWO and niCCWO. However, the wedge anglerequired increased to a small degree in comparison to theTPA as the TPA increased. The coCBLO and TPLO/CCWOrequired much smaller wedge angles due to the concurrentrotational component for TPA reduction; however, the aver-age wedge angles required did not change with larger TPA.The potential bene ﬁt of a cranial TLAS in tibias with eTPAhas been frequently theorized due to the resultant correctionof proximal tibial procurvatum.5,19,20,23Prior studies havedemonstrated that a larger cranial TLAS results in under-correction of TPA, though some studies utilized a standardTPA-based wedge angle as opposed to achieving a target TPAbased on a virtual correction.22,24The severe and extremeTPA groups represent a signi ﬁcant deformity of the proximaltibia rather than a small variation from normal TPA indogs. Although the underlying mechanism is unclear, thisFig. 3 Scatterplots of outcome measures versus tibial plateau angle. Pearson correlation coef ﬁcient (r) and the p-value (p) are provided for eachproximal tibial osteotomy. Signi ﬁcance was set at p<0.05. Cranial closing wedge ostectomy (CCWO); modi ﬁed cranial closing wedge ostectomy(mCCWO); tibial plateau levelling osteotomy with cranial closing we dge ostectomy (TPLO/CCWO); isosceles cranial closing wedge ostectomy(iCCWO); neutral isosceles cranial closing wedge ostectomy (niCCWO); and coplanar CORA-based levelling osteotomy (coCBLO)..proximal tibial morphology shifts the mechanical axiscaudal and distal compared with normal. The proximal tibialosteotomies performed on these extreme morphologiestherefore have a more dramatic effect. A prior study demon-strated that larger tibial anatomical-mechanical axis anglesare associated with a predisposition to cranial cruciateligament rupture in the dog, which could support the bene ﬁtof a cranial TLAS in dogs with eTPA.25The mean TLAS acrossall TPA in this study ranged from 1.4 to 6.5 degrees for thevarious proximal tibial osteotomies, and the mean TLAS formCCWO and CCWO were similar to those reported in previ-ous studies.5,20,22,23The TPLO/CCWO had the least impact on tibial sagittalplane alignment across all TPA. This proximal tibial osteot-omy required signi ﬁcantly smaller wedge angles ( p<0.001)due to the concurrent rotational component, which resultedin the removal of a smaller bone wedge, larger osteotomyoverlap, and minimal changes to tibial length and tibialtuberosity position. However, TPLO/CCWO is the only proxi-mal tibial osteotomy that requires ﬁxation of three separatebone segments, which may increase the technical challengeand compromise load sharing. Complication rates withTPLO/CCWO were increased in previous clinical studies,with multiple surgeries required in 33 to 67% of cases.5,8Use of TPLO alone with increasing TPA could be considered tomitigate these concerns, but was only tested with moderateTPA in this study (TPA /C2034 degrees). Data using TPLO alonefor severe and extreme TPA would have likely been equiva-lent with minimal-to-no effect on the primary outcomemeasures and therefore this comparison was not tested.The bene ﬁts of neutral tibial alignment must be consideredin light of technical complexity and published complicationrates when considering this technique for an individualclinical case.The coCBLO resulted in the largest TLAS and cTTS, whilepreserving osteotomy overlap and resulting in an averageincrease in tibial length. These results are not surprising,given that the coCBLO achieves TPA reduction throughcranial shift of the tibial tuberosity and tibial axis effectivelyraising the position of the intercondylar eminence. Giventhat the degree of tibial lengthening was quite small relativeto the overall tibial length, this change may not be clinicallysigniﬁcant. The coCBLO tibias had signi ﬁcant cranial over-hang of the proximal segment due to the sharp curvature ofthe wedge and degree of segment rotation, resulting inreduced osteotomy overlap that was most apparent withextreme TPA. Finally, two different size saw blades may beemployed clinically; however, this functionality was notpossible with the version of templating software used forthis study.The CCWO had the largest degree of tibial shortening anddTTS overall, and the smallest amount of osteotomy overlapin the extreme TPA group; however, it minimized TLAS andwas subjectively the simplest wedge to plan radiographically.The major impact on tibial length is primarily due to the largewedge surface area.15The mean tibial shortening for CCWOwas 6.5 mm, which was larger than that in previous studies,which reported means of 2.5 mm15and 3 mm.26This differ-ence is likely due to a combination of the larger average pre-simulation TPA in our study, and our ability to more accu-rately assess changes to tibial length due to the virtual studydesign. Ultimately, the large degree of tibial shortening foundwith this proximal tibial osteotomy may increase the risk ofﬁbular fracture, patella baja, sti ﬂe hyperextension and pa-tellar desmitis, which may discourage its use in patients withextreme TPA.8,15,23The iCCWO was intended to create optimal alignment ofthe cranial and caudal cortices and allow for more proximalwedge positioning, both of which would reduce TLAS.16TheiCCWO had a larger average TLAS than the CCWO, but still ledto a similar degree of tibial shortening and dTTS due to therelatively large wedge surface area. Despite the large loss oftibial length, a prior clinical study showed no evidence ofstiﬂe hyperextension secondary to patella baja with theiCCWO.16Additionally, the iCCWO achieved 100% osteotomyoverlap in all tibias, which may contribute to improved load-sharing and construct stability, and results in a moreanatomic postoperative appearance.The mCCWO and niCCWO are modi ﬁcations of CCWO andiCCWO, respectively, with the goal of removing a smallerbone wedge to increase proximal surface area for implantsand reduce tibial shortening via a partial opening wedge.15Ina previous study, mCCWO resulted in a wedge length 23%smaller than CCWO.23The mCCWO and niCCWO resulted inmoderate changes to tibial morphology for most outcomemeasures in our study, aside from niCCWO ’s low osteotomyoverlap across all TPA groups.The mCCWO and niCCWO led to an average increase intibial length. This was not reported in previous studiesevaluating mCCWO and no studies to the authors ’knowledgehave evaluated niCCWO. This ﬁnding may be related tovariations in planning between studies or tibial morphology.The clinical effects of this small increase are unclear, butcould potentially be related to postoperative complicationsor phenomena such as tibial rock back. Given the moderatechanges to tibial alignment in the sagittal plane whilepreserving osteotomy overlap and potentially eliminatingthe concern for tibial shortening, mCCWO may be a balancedoption for correction across a range of eTPA.The primary limitation of this study was the virtualcorrection radiographic design, as clinical outcomes couldnot be evaluated and reproducibility of these results in vivois unknown. We performed virtual corrections based on thepublished techniques in collaboration with co-authors;however, individual surgeon modi ﬁcations may yield dif-ferent results. Using computer-simulated proximal tibialosteotomies also allowed for improved accuracy whenperforming pre- and post-simulation measurements andachieving ideal surgical outcomes, which could be dif ﬁcultto recreate in a clinical setting. We made the a prioridecision to test the six osteotomy techniques, includinguse of TPLO and CBLO alone with moderate TPA, but onlycombination TPLO/CCWO and coCBLO with severe andextreme TPA. This was in line with the authors ’clinicalcase experience but does not preclude the use of TPLO orCBLO alone with increasing TPA. Additional limitations.include the variability of proximal tibial deformities in thesagittal plane, small sample size and lack of investigationoutside of the sagittal plane. However, this study designallowed for the use of the same set of tibias for each virtualcorrection, which provided a built-in control that mayreduce potential bias introduced by the small sample size.Incorporation of de ﬁned measurement points and TPA linesdrawn by a single investigator was done with the goal ofreducing this potential source of error between observermeasurements. Finally, only tibias from dogs more than20 kg were included in this study, so the impact of theproximal tibial osteotomies on smaller tibias with differentpotential morphology was not addressed.In conclusion, mCCWO had a moderate impact on tibialtuberosity positioning and TLAS, while maintaining tibiallength and a high osteotomy overlap across a range of TPA.The TPLO/CCWO demonstrated minimal changes to sagittalplane tibial alignment; however, the reduced osteotomyoverlap at the site of proximal segment rotation and thecreation of three separate bone segments may lead toincreased technical challenge. The CCWO, iCCWO, coCBLOand niCCWO had greater impacts on sagittal plane tibialalignment; however, the clinical signi ﬁcance of these effectsis unknown. Further investigation into the clinical impact ofchanges in tibial length, tibial tuberosity positioning, osteot-omy overlap and TLAS is warranted to better predict theclinical outcomes associated with these proximal tibialosteotomies and assist with designing alternative surgicaloptions for correction of eTPA in the dog. Consideration of theseverity of eTPA and the speci ﬁc effects of each technique fora given TPA range is relevant when selecting a proximal tibialosteotomy approach.

Answer 134

The results of this study supported the accep -tance of both hypotheses 1 and 2. The first hypothe -sis was that the manufacturer settings would gener -ate a platelet fold change > 1, which was supported by an average result of 1.31 times that of baseline, with 50% of samples in group 1 generating a > 10% increase compared to the baseline platelet count. These results are lower than previously reported, with prior studies reporting a platelet fold change between 1.55 and 2.5 times that of baseline.27 The second hypothesis was that when comparing vari -ables alone, increasing centrifugation speed or time would be associated with lower platelet fold change, which was supported by analysis of the individual variables. However, none of the protocols tested using the ACP double-syringe system generated fi -nal products with a platelet fold change consistent with the general definition of PRP, which has a fold change of approximately 3 to 7 times that of base -line whole blood.28 A fold change of this magnitude would be unlikely to achieve considering the single soft spin utilized by this system. The systems that generate this type of PRP generally concentrate the platelet layer further through additional spin cycles or by apheresis.Of the different protocols tested in this study, the protocol for group 3 produced PRP with the most consistently increased platelet fold change. Group 3 had the lowest relative centrifugation force and the least time of any of the groups, with 580 X g for 5 min -utes. These results may suggest that the manufactur -er settings utilize a centrifugation speed that may be higher than optimal. Given the origins of this system in equine patients and the subsequent adoption of the system for canine patients, adjustments to the pro -tocol should be made to tailor the system more nar -rowly to the specific cellular components of dogs.29,30The clinical relevance of a lower platelet fold change than the general definition of PRP is unknown, considering previous studies have reported positive outcomes in a model of canine anterior cruciate liga -ment and meniscal deficiency using this system.31,32 Although the PRP products generated with this sys -tem in this study did not concentrate canine platelets to the extent reported for other systems, all groups produced a significantly leukocyte-reduced product (Table 2). These findings suggest that the biologic produced using the ACP double-syringe system may provide greater anti-inflammatory effects than sys -tems that produce leukocyte-rich PRP. Specifically, group 3 had decreased neutrophil and lymphocyte populations but also had statistically significantly concentrated monocytes in addition to platelets. This reduction of selective leukocytes may be an addition -al benefit of the protocol used in group 3, consider -ing IL-1 ra originates from monocytes. IL-1 ra acts to mitigate the proinflammatory cytokine, IL-1 b, which is linked to the progression of osteoarthritis.33,34One of the major advantages of this system in small animals is the relatively low volume of start -ing whole blood. The subjects in this study were all ≥ 17 kg, allowing the blood draws performed to be < 2% of the patients’ total blood volume. However, sin -gle weekly blood draws of up to 7.5% of total blood volume (6 mL/kg) have been reported to be safe in Table 2 —Comparison of leukocyte and Hct concentrations compared to baseline means by group, as shown by the difference from baseline and 95% CI. Group Total leukocytes (K/ µL) Neutrophils (K/ µL) Monocytes (K/ µL) Lymphocytes (K/ µL) Hct (%)1 –3.0 (–4.6 to –1.3)* –3.5 (–4.4 to –2.5)* –0.01 (–0.14 to 0.13) 0.70 (–0.05 to 1.45) –35 (–39 to –30)*2 –5.6 (–7.2 to –4.0)* –4.4 (–5.3 to –3.5)* –0.09 (–0.22 to 0.04) –0.72 (–1.44 to –0.01) –40 (–44 to –35)*3 –1.9 (–3.4 to –0.4) –3.3 (–4.2 to –2.5)* 0.24 (0.11 to 0.37)* 1.23 (0.54 to 1.92)* –33 (–37 to –28)*4 –4.0 (–5.5 to –2.5)* –3.6 (–4.5 to –2.7)* –0.07 (–0.19 to 0.06) –0.16 (–0.85 to 0.53) –33 (–37 to –28)*5 –4.3 (–5.9 to –2.8)* –3.7 (–4.6 to –2.8)* –0.08 (–0.21 to 0.05) –0.30 (–1.01 to 0.41) –36 (–41 to –32)**P value < .001.Table 3 —Comparison of blood cell concentrations between speed and time variables, as shown by the difference between the variables and 95% CI. Negative values indicate that the first value is lower than the second, while hold -ing the other variable constant. Centrifugation Platelets Total Leukocytes Neutrophils Monocytes variables (K/µL) (K/ µL) (K/ µL) (K/ µL) LymphocytesRCF (X g) 1,304 vs 906 –40 (–112 to 33) –1.2 (–3.0 to 0.7) –0.1 (–1.1 to 0.9) –0.11 (–0.28 to 0.06) –1.0 (–1.9 to –0.1) 1,304 vs 580 –125 (–196 to –55)* –2.5 (–4.3 to –0.8) –0.5 (–1.5 to 0.4) –0.25 (–0.41 to –0.09) –1.6 (–2.4 to –0.7)* 906 vs 580 –86 (–139 to –32)* –1.4 (–2.7 to –0.1) –0.5 (–1.2 to 0.3) –0.14 (–0.26 to –0.02) –0.5 (–1.2 to 0.1)Time (min) 10 vs 5 –97 (–151 to –43)* –2.5 (–3.8 to –1.1)* –0.6 (–1.3 to 0.2) –0.21 (–0.33 to –0.09)* –1.4 (–2.1 to –0.8)*See Tables 1 and 2 for key.Unauthenticated | Downloaded 11/03/23 05:59 AM UTC 5dogs.35 With this in mind, this double-syringe sys -tem could be used in patients as small as 2.5 kg. The drawback of the low volume of starting whole blood is the potential for low volume of PRP generated. The volume obtained in this study ranged from 0.5 to 7 mL, with no significant difference found among groups. This large volume discrepancy is more likely due to the inherent patient variability and hydration status than due to the differences in group proto -cols. Often in a clinical setting, multiple joints of a patient may be injected in a single session, and the ideal volume to be injected is yet to be determined. Additionally, the volume of the joint spaces of these small patients will likely necessitate a small volume of therapeutic agent, so as not to overly distend an already inflamed joint. Although the volume an indi -vidual blood collection may yield is difficult to pre -dict prior to processing, if a volume deficit arises, it may be mitigated by preparation of a second ACP syringe or with the addition of other intra-articular therapies, such as hyaluronic acid.36A range of factors affect the quality of PRP gen -erated by a single individual on 1 occasion. However, in clinical settings, the quality of the PRP product is rarely analyzed for cellular composition. The method of analysis used in this study, applied to a clinical set -ting, would allow practitioners to gain insight into the outcomes achieved following PRP administration.This study looked to optimize variable parame -ters within a specific PRP system; this was not a clin -ical efficacy study. No claims regarding the overall efficacy of PRP therapy in dogs or of the PRP formu -lations evaluated in this study can be made. Further studies to evaluate the specific cytokine and growth factor concentrations yielded by specific protocols as well as extensive clinical trials are necessary. Due to the inherent patient and user variability associ -ated with biologics, specific factors may influence whether platelets are concentrated in a PRP.This study demonstrated the importance of eval -uating biological samples prior to administration to predict and improve patient outcomes. The future of regenerative medicine in small animals holds incred -ible promise for treating a plethora of disease pro -cesses, yet there is much still to be determined for optimization of these biologics.AcknowledgmentsIdexx Laboratories provided the CBC analysis for this study.The authors have nothing to declare.

Answer 135

In our population, CLA-EU led to an improve -ment in urinary continence scores for the majority of dogs. However, in the initial short-term follow-up at 4 weeks, full urinary continence was achieved in only 46% of dogs. The rate of urinary continence increased to 63% following initiation of additional medical management (most commonly with phen -ylpropanolamine) or additional surgical procedures. An improvement in urinary continence grade was demonstrated for 80.5% of dogs at short-term fol -low-up. These rates of urinary continence and im -provement in continence scores following CLA-EU match previous studies and add further evidence to these reported rates.15–18 This also suggests that Golden Retrievers with iEU have a similar prognosis to other breeds following CLA. However, the 37% of cases that never regained urinary continence and the 9.8% of cases that were humanely euthanized due to urinary-associated complications demonstrate that caution is indicated when discussing prognosis in cases of iEU.One factor proposed to be involved in dogs that fail to regain urinary continence is the pres -ence of concurrent urethral sphincter mechanism incompetence (USMI). USMI can be both congeni -tal or acquired in dogs,26 is thought to be the most common cause of acquired urinary incontinence in dogs,27 and is more common in dogs weighing > 15 kg.28 Definitive diagnosis of USMI can be made by urethral profile profilometry, but a positive response to α-adrenergic medication can also be suggestive of the condition.29 A number of dogs in this study regained continence following the introduction of phenylpropanolamine, supporting the involvement of concurrent USMI in ongoing incontinence fol -lowing CLA-EU. Due to their body weight, Golden Retrievers are thought to be more at risk for USMI than smaller-breed dogs. Therefore, it might be ex -pected that Golden Retrievers would be less likely to regain continence following CLA-EU than smaller-breed dogs. However, as stated above, in our study we found Golden Retrievers to have a similar rate of urinary continence following correction of ectopic ureters to the mixed-breed populations described in other studies.15–18We were unable to accept our hypothesis that normal bladder compliance and the presence of a well-defined bladder neck would be associated with an increased chance of achieving urinary continence following CLA-EU. This finding contrasts with previ -ous suggestions that other structural causes of in -continence in female dogs may represent prognos -tic factors in dogs undergoing CLA-EU.9,19,22–24 It is possible, however, that rejection of our hypothesis here represents a type II error associated with the small number of cases with reduced bladder compli -ance (10 [32.3%]) and poorly defined bladder neck (6 [19.34%]). Moreover, due to the subjective nature of both factors and lack of urodynamic studies per -formed,29 these conditions may have been incon -sistently identified, thus leading to rejection of our hypothesis. Further studies with larger sample sizes and objective assessment criteria for bladder com -pliance and the presence of a defined bladder neck are warranted.Presence of a urinary tract infection has previ -ously been found not to be associated with achiev -ing urinary continence following CLA-EU,3 and this finding was corroborated in our study. Positive urine culture results at the time of the procedure were associated with neither short- nor long-term conti -nence, but this result may have been impacted by false-negative urine culture results due to antibiotic administration at the time of CLA-EU in 4 dogs. How -ever, when the historical presence of urinary tract infections prior to CLA was assessed, this was signifi -cantly associated with a reduced chance of achiev -ing both short- and long-term urinary incontinence. This broader assessment of urinary tract infections may have allowed identification of cases highly pre -disposed to urinary tract infections and may have specifically identified cases with clinical urinary tract infections rather than incidental bacteriuria at the time of CLA-EU, hence explaining the difference in findings. It is possible that these cases are predis -posed to urinary tract infections due to anatomical factors other than purely their ectopic ureters30 and that these anatomical findings also predispose to on -going incontinence.Our study found ureteral dilatation to be asso -ciated with short-term but not long-term urinary continence. This distinction may explain, at least in part, why there are contrasting reports in the litera -ture over the association between hydroureters and urinary incontinence following correction of ecto -pic ureters.3,25 Moreover, this finding is interesting, as previous reports suggesting ureteral dilatation as a positive prognostic factor all involved surgical correction of ectopic ureters25 rather than CLA-EU. However, due to large CIs associated with this finding and the lack of ultrasonographic follow-up of cases with ureteral dilatation, it is challenging to place too much weight on this finding and further studies are required to explore this further.The main limitations of this study were the small number of patients predisposing to type II errors, heterogenous long-term follow-up, and inherent subjectivity in assessing the degree of urinary conti -nence. There was also a bias in that more long-term follow-up was available for cases that had less im -provement in urinary continence scores. The single short-term follow-up time point was selected to al -low postprocedure urinary continence to be graded prior to the initiation of any adjunctive medication. Further limitations included the lack of follow-up im -aging to identify ureteral opening location, lack of urodynamic testing, and subjective nature of grad -ing the presence of a distinct bladder neck and blad -Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 12/24/23 09:43 AM UTC6 der compliance. There were a number of limitations related to the retrospective nature of the study. In-clinic reevaluations were not performed (due to financial limitations), which could have allowed re -peated ultrasonographic assessment, cystoscopic assessment, and urine bacteriological testing in dogs that were persistently incontinent. The retro -spective nature of the study may have led to errors in the clinical information withdrawn from the medical records, issues with medication history or history of urinary tract infections being incorrectly recorded in the original clinical notes, and failures in recall from owners regarding their dog’s urinary continence 1 month after the procedure. Finally, the definition of historical urinary tract infections was taken on the basis of reviewing clinical notes and unfortunately urine culture results were not available for all cases prior to CLA-EU.In conclusion, we have reported the outcomes following CLA-EU of a homogenous group of female entire Golden Retrievers. This study suggests that Golden Retrievers with ectopic ureters have a simi -lar rate of continence following CLA-EU as reported previously for other populations of dogs undergoing correction of iEU. Moreover, this study demonstrates the challenges in identifying pre- or perioperative factors found to give prognostic information regard -ing achievement of urinary continence. In this popu -lation, the only factors found to be significantly as -sociated with both short- and long-term continence were the absence of historical urinary tract infections (short and long term) and increased dilatation of the most severely affected ectopic ureter (short term only). Due to the retrospective nature of this study and the small number of animals, further prospec -tive studies are warranted to assess the prognostic factors identified.AcknowledgmentsNone reported.DisclosuresThe authors have nothing to disclose. No AI-assisted technologies were used in the generation of this manuscript.FundingThe authors have nothing to disclose.

Answer 136

Lipomas are benign, usually slow growing, tumours from adi -pose tissue that are common in middle to older- aged dogs). Non- infiltrative lipomas are often of little clinical significance, though large tumours can cause mobility disturbances or pathologies secondary to compression of vital structures such as nerves and the spinal cord (Morgan et al. 2007 , T rębacz & Galanty 2016 , Kimura et al. 2018 ). In this case, the subcutaneous lipoma was of substantial size in the cervical and axillary region causing com -pression of the right jugular vein and leftward deviation of the right carotid arteries and adjacent structures. The known primary causes of chylothorax are often associated with obstruction of flow of chyle with vascular compression or occlusion. Previous reports describe cases of chylothorax secondary to thrombosis of the cranial vena cava following jugular vein disturbances (central venous catheter, endocardial pacing wire and vascular access port) (Mulz et al. 2010 , Singh & Brisson 2010 ). No evidence of a cranial vena cava thrombus was noted on the CT scan in this report. Experimental ligation of the cranial vena cava and heart base masses causing right atrial compression have also been described as primary causes for chylothorax in dogs (Fossum et al. 1986 , Gibson et al. 2021 ). The level of vascular obstruc -tion is this case was more cranial than previously described cases, which is typically at the level of the right atrium to jugulosubcla -vian angle (Fossum et al. 1986 ).In additional to primary occlusion of the cranial vena cava, conditions such as congestive heart failure, ventricular anoma -lies, and restrictive pleuritis are reported causes of chylotho -rax, presumably due to central venous hypertension (Fossum FIG 3. A delayed postcontrast, coronal computed tomographic image at the level of the trachea (A). A right- sided fat attenuating mass is present from the hyoid bones to the thoracic inlet and extending medial to the right scapula. There is a central region of non- enhancing soft tissue attenuating material with internal randomly arranged mineralization, consistent with an area of necrosis. A delayed postcontrast, axial computed tomographic image at the level of C6, just cranial to the thoracic inlet (B). There is severe leftward deviation of the cervical trachea, oesophagus, carotid arteries, and adjacent midline structures. The right external jugular vein is severely compressed, and the right internal jugular vein is not clearly identified. A delayed postcontrast, axial computed tomographic image at the level of the heart (C). Bilateral pleural effusion is present and displacing the lungs dorsally 17485827, 2023, 11, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jsap.13625 by Vetagro Sup Aef, Wiley Online Library on [15/11/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseChylothorax secondary to a lipoma in a dogJournal of Small Animal Practice • Vol 64 • November 2023 • © 2023 British Small Animal Veterinary Association. 721 et al. 1994 , Campbell et al. 1995 , Tanaka et al. 2006 ). Central venous hypertension may lead to increased pressure within the lymphatic system, which terminates into the cranial vena cava and lead to chyle leaks and chylothorax. Central venous pres -sures were not measured in this report. Given the location of the cervical mass in this case and the lack of thrombosis within the cranial vena cava, venous hypertension secondary to a large cervical mass extending into the thoracic inlet was possibly the cause of chylothorax in this dog. A CT lymphangiogram was not performed and was not standard at this institution in work up of dogs with chylothorax. However, a lymphangiogram may have been particularly helpful if the chylothorax did not resolve and a second surgery to address they chylothorax was planned.Idiopathic chylothorax is the most common cause of chy -lothorax in dogs and rarely responds to medical management alone. Medical management includes thoracocentesis to drain the chyle, low- fat diet, rutin, prednisolone and/or octreotide (Birchard & Fossum 1987 , Birchard et al. 1995 , Thompson et al . 1999 , Markham et al . 2000 , Kopko 2005 , Reeves et al. 2019 ). In the 2 days prior to surgery, the dog in this case had therapeutic thoracocentesis and was fed a low- fat diet. Fol -lowing surgery, no medical therapy for chylothorax was neces -sary. No additional thoracocentesis was needed, the dog was transitioned back to balanced adult dog food by the time of hospital discharge, and the only medications sent home were for postoperative pain control. It was discussed with the owner prior to surgery that if the mass removal did not lead to resolution of the chylothorax, then additional surgery (thoracic duct ligation, cisterna chyli ablation and pericardiectomy) would likely be rec -ommended. Fortunately, the mass removal led to rapid resolu -tion of the chylothorax, and no additional surgery was required with the exception a minor procedure for PleuralPort removal.In conclusion, a large subcutaneous cervical mass was associ -ated with chylothorax, which rapidly resolved following surgical mass removal.Conflict of InterestNone of the authors of this article has a financial or personal relationship with other people or organisations that could inap -propriately influence or bias the content of the article.Author contributionsScarlett Sumner: Conceptualization (equal); data curation (equal); resources (equal); writing – original draft (lead); writing – review and editing (lead). Evangelia Makrygiannis: Conceptual -ization (supporting); data curation (supporting); writing – review and editing (supporting). Joseph Bartges: Conceptualization (equal); data curation (equal); resources (equal); supervision (equal); writing – original draft (supporting); writing – review and editing (equal). Chad Schmiedt: Conceptualization (equal); data curation (equal); resources (equal); supervision (equal); writing – original draft (supporting); writing – review and editing (equal).

Answer 137

In this ex-vivo study, statistically, VUA performed withunidirectional barbed sutures leaked at similar pressureas the anastomosis performed with conventional sutures.However, clinically, if a unidirectional barbed suture isused to complete a VUA, a urinary catheter will still beneeded since the leakage pressure of the VUA was 28%lower than when conventional sutures were used. Theunidirectional barbed suture was associated with ashorter suturing time than the conventional suture.Acute leakage pressure after a VUA has not beenreported frequently in animal models or clinical studiesafter radical prostatectomy in human patients. Duringhuman radical prostatectomy, the VUA is tested with aninjection of 100 to 300 ml sterile saline in the bladder witha urinary catheter.3,4,16,17If extravasation is observed mac-roscopically, additional suture bites are added, or tensionof the suture is adjusted. However, during this leak testing,pressures are not measured or reported. In two caninestudies, urethral anastomosis have been performed experi-mentally in dogs without signs of urine leakage in thepostoperative period.10,11However, in both of those stud-ies, leakage pressure was not measured and a urinary cath-eter was maintained for one to two weeks after surgery toFIGURE 1 Leakage pressure (mmHg) of vesicourethralanastomosis (VUA) performed with conventional sutures (C group)and unidirectional barred sutures (UBS group) ( p=.236).FIGURE 2 Suturing time (min) to perform a vesicourethralanastomosis (VUA) with conventional sutures (C group) andunidirectional barred sutures (UBS group) ( p< .0002).718 MONNET and HAFEZ 1532950x, 2023, 5, prevent a uroabdomen. Hafez et al.8reported a leakagepressure of 10.8 mmHg using conventional sutures in acanine ex-vivo model of VUA. In an ex-vivo porcine model,VUA leakage pressure ranged from 8.2 to 21.1 mmHg.2Those leakage pressures are similar to the pressuresrecorded in both groups in this study.The leakage pressures were statistically similar inboth groups. However, biologically the risk of urineextravasation is more likely increased with unidirectionalbarbed sutures since the leakage pressure of the VUAwas 28% lower with unidirectional sutures than with con-ventional sutures. The minimal acceptable leakage pres-sure to prevent extravasation after VUA is not known.However, since some samples treated with unidirectionalbarbed sutures leaked at pressure as low as 5 mmHg, therisk of uroabdomen should be increased with this suturematerial. Since the unidirectional barbs, including theterminal loop, were not present in the first 1.5 cm of thesuture, the first two or three suture bites for each unidi-rectional barbed strand were made with a conventionalsuture representing 28% to 42% of the entire anastomosis.Therefore, the unidirectional barbed suture did not pro-vide a better seal during VUA and should not result in areduction of the morbidity after VUA for radical prosta-tectomy in human patients.3,4,9,10,18,19The suturing time was reduced by 25% with unidirec-tional barbed sutures. Our findings were consistent withobservations made in many reports about robotic radicalprostatectomy.10,12,16,17,19 –21Suturing time has beenreported to be reduced with unidirectional barbed suturesprimarily because of the self-anchoring of the suture. Itdoes not require adjustment in the tensioning of thesuture during the anastomosis. In our study, the numberof suture bites used to complete the VUA was reducedwhen a unidirectional barbed suture was used, contribut-ing to the reduction in surgical time. The number ofsuture bites in our study seems higher than reported inclinical studies.10,12,16,17,19 –21During a laparoscopic orrobotic radical prostatectomy, 10 to 11 suture bites areplaced.10,12,16,17,19 –21In our study, the anastomosis wasperformed ex-vivo, which facilitates the suture placementcompared to laparoscopy or robotic surgery. The numberof suture bites placed was determined by subjective eval-uation of the tissue apposition during the completion ofthe VUA. Reducing the number of suture bites can bepotentially beneficial for tissue healing. It has beenshown that unidirectional barbed sutures can be associ-ated with fibrosis because of the trauma caused by thesuture getting through the tissue and by over tighteningthe suture.18,22This study has several limitations. It was a cadavericstudy; therefore, the interference of suture material with thehealing process could not be evaluated. The apposition oftissue was not evaluated with h istopathology because it wasan acute cadaveric study. However, the anastomosis withunidirectional barbed sutures looked subjectively better.5|CONCLUSIONSThe unidirectional barbed suture does not statisticallyaffect the acute leakage pressure in an ex-vivo caninemodel of VUA when compared to conventional sutures.However, since the leakage pressure was 28% lower whenunidirectional sutures were used, the morbidity afterVUA will be similar or increased when compared toVUA completed with conventional sutures. The utiliza-tion of unidirectional barbed sutures resulted in a shortersurgical time and fewer suture bite placements. Unidirec-tional barbed suture might facilitate laparoscopic radicalprostatectomy in dogs because it should facilitate intra-corporeal suturing.AUTHOR CONTRIBUTIONSHafez A, DVM and Monnet E, DVM, PhD have contrib-uted to establishing the experimental protocol and col-lecting and analyzing the data. Both authors contributedto the manuscript.CONFLICT OF INTEREST STATEMENTThe authors have no conflict of interest.ORCIDEric Monnethttps://orcid.org/0000-0002-0058-2210

Answer 138

Laparoscopy in small animals continues to be refinedand expanded. The addition of new surgical proceduresallows veterinary surgeons greater ability to help theirpatients and owners. Results from this study supportongoing research on LVSG in a live feline model. A learn-ing curve for new procedures is to be expected, in humanmedicine proficiency at LVSG is expected to be achievedafter 30 –120 procedures.18The cadaveric surgical compli-cation of stenosis encountered in this report would beserious in live patients therefore diligent care must betaken to ensure the stomach is not resected too close tothe lesser curvature. The first case documented with thiscomplication was performed without the benefit of anorogastric tube (case 2) and extensive removal of the fun-dus was being attempted. Techniques employed to avoidthis complication include placement of an orogastric tubeand refinement of the staple line. Placement of an orogas-tric tube did not prevent the gastrectomy line to bewithin 1.5 cm of the lesser curvature in case 4 whichappeared visually to create a stenosis at this location. Thismay have occurred due to excessive tension placed alongthe greater curvature during placement of the staplerpushing it directly next to the orogastric tube at this site.We do not know if this subjective stenosis would havecaused a clinical issue in live patients but in subsequentcases less tension was applied to the greater curvatureduring staple placement. The orogastric tube was alsomanipulated during the procedure to subjectively deter-mine how close the gastrectomy line was to the incisura.Neither of the live patients who underwent LVSG had avisually or a palpably stenotic resection when the orogas-tric tube was manipulated and the remaining stomachgrasped with laparoscopic Babcocks. Neither patient suf-fered any known gastrointestinal complications duringrecovery either. The resected section of the stomach mayhave been less in these patients compared to the cadaverspecimens as we could not weigh the remaining stomach.Future studies will need to determine the specific gastricresection amount for obesity control or glucose regula-tion. As comfort with this procedure increases, and meta-bolic data becomes available, specific surgical goals canbe determined.884 BUOTE ET AL . 1532950x, 2023, 6, While we did not encounter the complication of sta-pling through the orogastric tube in our cadaver speci-mens or live patients, this has been reported in humanmedicine.19Because of this, more robust specialized bou-gie tubes (Visigi3D bougie, Boehringer Laboratories,LLC, Phoenixville, PA, USA) are used in human bariatricsurgery and may be considered in a larger live animalmodel. In our live animal procedures, extreme care waspaid to staple firing location and ensuring the orogastrictube was freely moveable. Discussion preoperatively withthe anesthetic team is vital to ensure they understand theimportant role they will play as they oversee orogastrictube placement and manipulation.Because of the acute angle of the lesser curvature incats that we observed (Figure 6), the orogastric tubescommonly migrate laterally to the greater curvature. Inhuman medicine, placement of the first staple line at thecaudal aspect of the stomach allows for the tube to belodged into the aborad pocket. This technique was alsoemployed in our later cadaveric cases (cases 3 –10) andwas found to be helpful, but placement of this first stapleline dictates the location of the subsequent staple place-ments to some extent. In some human descriptions, theplacement of this first staple line should be approxi-mately 5 cm orad to the pylorus but other references usevisual cues as their guide.2In our live animal procedures,the author used only visual cues due to the cadavericexperience gained. The need for adequate tension to beapplied along the greater curvature to visualize the loweresophageal sphincter and lesser curvature cannot beoveremphasized. An alternative method might be the useof an endoscope which can be curved along the lessercurvature and would allow visualization of the stomachas the stapler is placed. Endoscopes have also been usedin some studies to assess for leaks from gastrectomy inci-sions instead of the methylene blue technique used inthis report.2,20Of note is the difference in the percentage of stomachremoved in the cadaver specimens we report comparedto the target percentage in human bariatric surgery.While we removed approximately 30% of the cadaverstomach based on weight, human surgeons aim for areduction of approximately 75% –80% of stomach volumeto appreciate an effect on weight and the endocrine sys-tem. In our live subjects we subjectively removed a simi-lar amount of the stomach compared to our cadaverprocedures and work is currently underway to evaluatethe utility of this procedure for weight loss. As this tech-nique appears safe in a live animal model future work isunderway to determine the specific amount of stomachthat must be removed in feline patients to generateweight loss. More recent work in humans has illustratedthat the amount of stomach may be less importantcompared to the endocrine cells (ghrelin receptors) pre-sent in the stomach that is resected so histopathologicalstudies are also necessary.21Traditional open partial gastrectomy is already per-formed in veterinary medicine for gastric necrosis asso-ciated with gastric dilatation volvulus and gastricneoplasia.22-25Complications encountered during theseprocedures include hemorrhage and leakage of gastriccontents from subsequent dehiscence, but the true inci-dence is unknown. A recent experimental caninecadaver study evaluating the bursting strength and leak-age of three incisional closures for partial gastrectomyreported a double layer suture closure provided the bestbiomechanical properties b ut placing a sutured oversewacross a stapled gastrectomy did decrease the incidenceof leakage.26As we did not have a similar study in cats,we used typical recommendations when choosing staplesize employing staples with closed leg lengths of similarheight as the thickness of the tissue. Ultrasonographicstudies in cats report a gastric fundus wall thickness canrange from of 1.7 –4.38 mm.12,13One study assessedanesthetized cats and found a mean fundus wall thick-ness of 2.0 mm (95% confidence interval, 1.7 –2.2).12Theother study investigated awake and sedated cats andfound the overall interrugal thickness to be 2.03 ± 0.41(range 1.1 –2.6) and overall rugal thickness to be 4.38±0 . 3 1 ( r a n g e 2 . 6 –7).13With this information we choseto use a graduated staple cartridge to account for varia-tion of the tissue. The TriStaple technology purple car-tridge reload has a stepped cartridge face that deliversgraduated compression and three rows of varied heightstaples. The open leg lengths range from 3-4 mm andclosed leg lengths from 1.25 –1.75 mm. The reportedresult of this design is a staple line that providesstrength and leak resistance without excessive compres-sion allowing better perfusion to the remaining tissue.27The traditional paradigm of using closed staple leglengths equal to the tissue thickness to avoid local ische-mia in edematous tissue ha sb e e nq u e s t i o n e di nh u m a nbariatrics.28A closed staple to tissue thickness ratio of <1 wasused in that human study and no signs of ischemic necro-sis were reported.While some surgeons do prefer to oversew the stapleline of the gastrectomy due to concerns of leakage,human staple devices most commonly include reinforce-ment material, so an oversew is not always performed.2,20These staple devices are more expensive than the typicalstaples employed in veterinary medicine, and it is unclearif this equipment will become economically feasible inday-to-day veterinary practice. Neither live patient exhib-ited any gastric healing complications with the unrein-forced staple cartridge without a suture oversew; futureBUOTE ET AL . 885 1532950x, 2023, 6, studies in cats may determine the ideal staple size, type,and closure for this procedure.This study has several limitations predominatelyrelated to the cadaveric design which include the lack ofintraoperative bleeding or movement of structures as wellas inability to monitor postoperative complications (pain,dehiscence, and motility disorders). While this is partiallymitigated by the inclusion of two live cat procedures, alarger prospective case series is necessary to ensure safetyand assess efficacy. Future studies could also comparethis technique to standard laparotomy with regards tosurgical times, amount of stomach resected and weightloss outcomes. The authors suspect that a larger percent-age of stomach would be removed in an open proceduredue to the ability to palpate the anatomic structuresdirectly, but it remains to be seen if this benefit over-comes increased discomfort to the patient. The best staplesize and gastric closure method in cats for partial gastrec-tomy has not been determined in ex vivo or in vivostudies and refinement of these procedures may bemade based on these studies in the future. The authorsfollowed recommendation f or leak testing based onhuman LVSG procedures and in the two clinical casesthis was feasible and appears effective but burstingstrength pressure testing should be pursued in futurestudies. This initial study showed promising resultsregarding safety and further investigations are under-way to determine appropriate pre- and postoperativepatient management.In conclusion, laparoscopic vertical sleeve gastrec-tomy is feasible in a feline cadaver model and has beensuccessfully performed in two live feline patients. Nointra- or postoperative complications in the live cats wereencountered supporting ongoing research into this proce-dure for bariatric and endocrine disease management.AUTHOR CONTRIBUTIONSNicole J. Buote, DVM, DACVS-SA: Substantial contribu-tions to the conception of the work; the acquisition, anal-ysis, and interpretation of data for the work; drafting thework, revising it critically for important intellectual con-tent; final approval of the version to be published; agree-ment to be accountable for all aspects of the work inensuring that questions related to the accuracy or integ-rity of any part of the work are appropriately investigatedand resolved.Ian Porter, DVM, DACVR: Substantial contribution tothe conception of the work and acquisition. Revising itcritically for important intellectual content; finalapproval of the version to be published; agreement to beaccountable for all aspects of the work in ensuring thatquestions related to the accuracy or integrity of any partof the work are appropriately investigated and resolved.John Loftus, PhD, DVM, DACVIM: Substantial contribu-tion to the conception of the work and acquisition. Revis-ing it critically for important intellectual content; finalapproval of the version to be published; agreement to beaccountable for all aspects of the work in ensuring thatquestions related to the accuracy or integrity of any partof the work are appropriately investigated and resolved.Bethany Cummings, DVM, PhD: Substantial contributionto the conception of the work and acquisition. Revising itcritically for important intellectual content; finalapproval of the version to be published; agreement to beaccountable for all aspects of the work in ensuring thatquestions related to the accuracy or integrity of any partof the work are appropriately investigated and resolved.Gregory F. Dakin, MD, FACS: Substantial contribution tothe conception of the work, and interpretation of data forthe work; revising it critically for important intellectualcontent; final approval of the version to be published;agreement to be accountable for all aspects of the workin ensuring that questions related to the accuracy orintegrity of any part of the work are appropriately investi-gated and resolved.CONFLICT OF INTERESTThe authors declare no conflict of interest related to thisreport.ORCIDNicole J. Buote https://orcid.org/0000-0003-4623-3582

Answer 139

In four dogs, we report the clinical outcomes of coccygeal ver -tebral fractures managed with open reduction and internal fixa -tion (plates and screws). Complications were identified in two dogs (dogs 3 and 4) after surgery and were considered major and treated medically. All dogs had an excellent outcome at a mean follow- up time of 40 weeks with the normal function of the tail based on the client questionnaire. External coaptation was applied to prevent excessive movement of the tail following surgery and protect the repair and was considered an adjunctive part of the treatment. This was tolerated by three of four dogs.SSI remains a risk in all surgical procedures, with previously published rates in dogs and cats ranging from 0.8% to 18.1% (Nelson 2011 ). The incidence of SSI in clean orthopaedic proce -dures was reported between 3.3% and 7.1% and can precipitate serious complications with biofilm formation and associated bac -terial resistance (Holmberg 1985 , Whittem et al. 1999 , Craw -ford et al. 2016 ). SSI, as classified in a previous study by T urk et al. (2015 ), occurred in one dog (dog 3). Prophylactic periop -erative antibiotics were administered in all cases. We elected that for several reasons. First, we used implants for internal fixation, which is an area with a poor soft tissue envelope. The proxim -ity to the perineal area and relatively prolonged contact with the floor (while sitting or lying) may contribute to increased bacterial contamination. The protective role of postoperative antimicrobi -als over SSI in clean orthopaedic surgery remains a controversial topic and reports are contradictory (Holmberg 1985 , Whit -tem et al. 1999 , Weese 2008 ). A prospective study by Aiken et al. (2015 ) concluded no significant difference between SSI rates in dogs treated with or without postoperative antibiotics beyond the immediate postoperative period, however, further postoperative antimicrobial therapy was not continued in dog 3. Additional factors that may have contributed to the development of SSI might be damage to the local blood supply with electro -cautery or bandage- associated complication, although these were considered unlikely. The infection resolved after antimicrobial treatment and removal of the exposed suture without any radio -graphic evidence of osteomyelitis and implant- associated infec -tion. Fracture union was achieved at 31 weeks postoperatively.One dog (dog 4) experienced prolonged postoperative pain, subsequent implant loosening, and delayed union. We suspect several factors may have contributed to this. The more caudal the vertebrae, the less soft tissue coverage and blood supply and the smaller the vertebrae’s size (Evans et al. 2020 ). This required the use of a 1.0 mm plate and screws being limited by the verte -bral body size (10×3.7 mm). These are the smallest commercially available implants and are expected to be mechanically inferior due to reduced thickness and area moment of inertia, in com -parison to larger- size plates. Moreover, the caudal part of the tail is the most mobile and hence subject to the largest forces, which may require a longer period of external coaptation. In addition, the caudal coccygeal vertebrae in dog 4 radiographically appear to consist mainly of cortical bone with minimal cancellous bone and similarly to the distal radius in toy breeds (Welch et al. 1997 ) may be subject to reduced intraosseous vascularity, which may con -tribute to delayed and non- unions. Finally, imperfect apposition of the fracture fragments, suspected lower construct stiffness or technical error (insufficient screw tightening) may contribute to excessive interfragmentary micromotion and implant loosening.Our surgical technique slightly differed from the previously reported by Robertson and Miller ( 1986 ). We used a lateral FIG 7. Dorsoventral and mediolateral views 8 weeks (a,b) and 17 weeks (c,d) postoperativelyA CB D8 weeks post op 17 weeks post opFIG 6. Dorsoventral and mediolateral views 6 weeks (a, b) and 7 months postop (c, d)AB DC 17485827, 2023, 10, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jsap.13644 by Vetagro Sup Aef, Wiley Online Library on [19/10/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseI. A. Kalmukov et al.Journal of Small Animal Practice • Vol 64 • October 2023 • © 2023 British Small Animal Veterinary Association. 648approach and implant placement instead of a dorsolateral one. This was done to avoid or minimise damage to the largest arteries of the tail (medial caudal, dorsal lateral and ventral lateral arter -ies) and to take advantage of the relatively flat lateral surface of the caudal vertebrae. Lateral caudal arteries should be preserved as inadvertent damage can lead to skin necrosis, delayed and non- union and may increase the risk of infection. In all cases, no tour -niquet was used, and mild haemorrhage was observed only in one dog, but this was controlled with diathermy (dog 3). The same dog subsequently developed SSI but it is unclear whether this was a direct consequence of haemorrhage or the use of diathermy. Overall reported complications in the literature after caudectomy are minor in 20% of cases (Simons et al. 2014 ). These include cau -dal pain, infection, wound dehiscence, anal sphincter and rectal trauma (which would occur only in high tail amputations), with major complications described in up to 15% of cases (Simons et al. 2014 ) requiring revision surgery. Adapted to Cook et al., complications considered major in that study are in two of 20 patients (10%, both required revision surgery). This percentage may be higher if additional medical treatment has been prescribed but this information is not available. T wo patients (one dog and one cat) were treated with tail amputation due to fractures and did not develop complications, despite suspected pain in one. In our case series, two of four (50%) dogs suffered major complica -tions. These numbers are higher than those reported by Simons et al. (2014 ), however, due to the small number of dogs and differ -ent study designs, direct comparison and clear conclusions can -not be made. Further prospective studies with a larger number of cases would be more accurate in predicting expected complica -tion rates and would facilitate the comparison of outcomes.The overall prevalence of tail injuries is still considered low; however, specific breeds, including Pointer, Setter, Spaniels and sighthounds, were recognised to be at higher risk (Diesel et al. 2010 , Cameron et al. 2014 ). Despite this, based on our litera -ture search, the exact prevalence of caudal vertebral fractures is unknown, which can be a challenge in obtaining a larger number of cases.The tail is used in various ways and should be considered an important anatomical and physiological structure (Wans -brough 1996 , Bennett & Perini 2003 , Leaver & Reimchen 2008 ). Therefore, preservation of the tail is desirable and should be achieved if possible. In addition, preservation of the tail may reduce the risk of amputation neuroma, leading to chronic self- trauma, pain, alopecia, hyperpigmentation of the skin and dif -fuse thickening of the underlying connective tissue of the tail (Gross & Carr 1990 ).Limitations to this study include the small number of cases, its retrospective nature, and the subjective outcome measurement. The lack of a direct control group of dogs treated conservatively or with amputation can be another limitation which does not allow a direct comparison of outcomes and complications.Coccygeal fracture repair can be technically challenging due to the small size of fragments (case 4) and requires specific equip -ment (1.0 and 1.5 mm implant systems), moreover, in smaller patients or cats, the most caudal vertebrae may be too small and not suitable for internal fixation.In all our cases, the referrals were driven by the owners, who sought alternative treatments to amputation after a period of con -servative management that did not result in normal function or resolution of clinical symptoms. Owner motivation is an essential part of case selection but also the low frequency of these injuries, simplicity and good results with conservative management or tail amputation make it an injury where referral for alternative treat -ments is usually not sought.FIG 8. Necrosis of skin edges 5 days postop(a), tail tip dermatitis 14 days postop (b), wound dehiscence 16 days postop (c), granulation of wound 34, 49, 65 days postop (d,e,f). Partial epithelisation and suture exposure (black arrowheads) 70 days postop (g). Near full epithelisation of the surgical wound with small central scab 81 days postop (h)AE F GHB CD 17485827, 2023, 10, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jsap.13644 by Vetagro Sup Aef, Wiley Online Library on [19/10/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseCaudal vertebrae fracturesJournal of Small Animal Practice • Vol 64 • October 2023 • © 2023 British Small Animal Veterinary Association. 649 Good outcomes with excellent function were achieved in all our cases following fracture repair using internal fixation. Plate fixation is an adequate technique for coccygeal vertebral fractures and should be considered as a treatment option.AcknowledgementsThe authors would like to thank the staff at Fitzpatrick Referrals Orthopaedics and Neurology.Author contributionsI. A. Kalmukov: Writing – original draft (lead); writing – review and editing (equal). N. Schneider: Data curation (lead); inves -tigation (lead); resources (equal); writing – original draft (sup -porting). D. Miraldo: Methodology (equal); resources (equal); validation (supporting); writing – review and editing (equal). M. A. Solano: Data curation (lead); project administration (lead); validation (lead); writing – review and editing (equal).Conflict of interestNone of the authors of this article has a financial or personal relationship with other people or organisations that could inap -propriately influence or bias the content of the paper.

Answer 140

This is the first study to describe the clinical presentationand outcomes of dogs ≥15 kg with EHPSS. Median age ofthese dogs at the time of referral was just under 2 yearsTABLE 5 Continuation of medical management in 63 largedogs with extrahepatic portosystemic shunt (EHPSS) at ≥90 days.Medicalmanagement at≥90 days followingdischargeSurviving,attenuateddogs ( n=40)Nonattenuateddogs ( n=18)Antibiotics, diet,lactulose16/40 (40%) 11/18 (61.1%)Antibiotics, lactulose 0/40 (0%) 6/18 (33.3%)Diet, lactulose 3/40 (7.5%) 0/18 (0%)Diet 6/40 (15.0%) 0/18 (0%)None 15/40 (37.5%) 1/18 (5.6%)Note: Weaning of medical management in surviving dogs who receivedattenuation of their EHPSS versus those that were solely medicallymanaged.TABLE 6 Survival data in 63 large dogs with extrahepatic portosystemic shunt (EHPSS).Patient groupMedian survivaltimeSurvival rateat 1 yearSurvival rateat 2 yearsSurvival rateat 5 yearsAttenuated dogs ( n=45) ≥1842 days 89% 77% 77%Nonattenuated dogs ( n=18) 543 days 82% 49% 24%Note: Median survival times and survival rates associated with surviving dogs who received attenuation of their EHPSS versus those that did not receiveattenuation.SPIES ET AL . 283 1532950x, 2024, 2, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14040 by Cochrane France, Wiley Online Library on [14/02/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licenseof age, similar to reported demographics for typical smallbreed EHPSS dogs and large breed IHPSS dogs.8,14,19,23Golden retrievers appear to be over-represented inthis group; however, true incidence cannot be assessed asinstitution-specific frequency of this breed was notassessed. Previous cases of Golden retriever, Germanshepherds, and Great Pyrenees with EHPSS have beenreported.8Predilections between large breed dogs such asthe Golden retriever, Labrador retriever, and Irish Wolf-hound and a single, congenital IHPSS are well-established.1,9The most common clinical signs and laboratoryabnormalities were consistent with decreased hepaticmetabolic and synthetic function, which is expectedgiven the pathophysiology of this condition. Clinical his-tory, presenting complaints, and the nature of preopera-tive medical management in these dogs were comparableto typical small breed EHPSS dogs.3,6,8,19The nature ofclinical signs and chemistry panel changes were alsoreflective of what has previously been reported for typicallarge breed dogs with IHPSS.8,24Most common shunt types in typical small breed dogsinclude splenocaval, left gastrophrenic, left gastroazy-gous, and right gastric shunts.4Although splenocavalshunts were one of the most common shunt types in thisstudy and found in a quarter of dogs, another quarterwere simply described as portocaval shunts. Other morecommon shunts included splenonephric and splenoazy-gous, which are not typically seen in small breed EHPSSdogs.4The presence of atypical shunt configurations hasbeen associated with breeds that are not historically pre-disposed to congenital shunts, a finding that is potentiallysupported by these results given the rarity of reports ofcongenital splenonephric and splenoazygous shunts.9Further investigation into the presence of uncommonshunt configurations in unexpected breed-shunt combi-nations is warranted. Shunt anatomy was not describedin over 10% of the dogs and the breadth of imagingreports was variable, precluding commentary on the rela-tionship between specific shunt type and the likelihoodof intra- or postoperative short-term complications, orwith survival at follow-up.Unfortunately, we could not definitively comment onthe correlation between shunt and/or portal vein anat-omy and complications or survival given the low numberof dogs with complications and/or shunt-related deaths,as well as the lack of standardization of imaging proto-cols and reports. Repeated imaging was not performed inmany dogs to document if multiple acquired PSS devel-oped in response to portal hypertension. The frequencywith which postoperative portal hypertension occurredmay be underestimated; however, many dogs were ableto tolerate a reduction in their medical managementprotocols which supports the idea that portal blood flowwas improved. Post-attenuation histopathology (eitherfrom repeat liver biopsy or necropsy) was not performedor provided for any dog, and post-attenuation imagingreports were not provided. Future anatomic studies tocharacterize portal vein diameter in large breed EHPSSdogs may be of merit. It is important to note, however,that in the presence of a shunt blood flow will follow thepath of least resistance, resulting in under-filling ofthe portal vein. Ultimately, intraoperative assessment oftemporary shunt occlusion is critical in providing under-standing of how a dog may tolerate attenuation.Documented shunt-related mortality in nonattenu-ated and surgically managed large breed dogs withEHPSS were comparable, if not lower, than mortalityrates associated with the more commonly encounteredsmall breed dogs with EHPSS. Similarly, surgical treat-ment was associated with less shunt-associated mortality.In our study, the rate of documented, shunt-relateddeaths for surgically managed dogs was just under 7%.This is equivalent to, and in some cases, lower than, whathas been reported for small breed dogs with EHPSS man-aged surgically, with mortality rates ranging from 2% to27% in established literature3,9,12,13,14; however, thesestudies reflect larger case populations and variablefollow-up periods. Slightly less than a quarter of the non-attenuated dogs in the present study experienced docu-mented shunt-related deaths. This is equivalent to ratesreported in literature for small breed dogs with EHPSS,albeit with different follow-up periods.3,25Current recom-mendations for surgical treatment of EHPSS in smallbreed dogs may be extended to large breed dogs withEHPSS.Limitations of this study included lack of standardiza-tion of diagnostic imaging, intraoperative assessment,and laboratory tests. The minimum weight cutoff of15 kg at time of initial work-up, which was selected basedon expected minimum average weights of typical largebreed IHPSS dogs,8,9may have led to exclusion ofdogs who gained weight following their referral visit(i.e., dogs who went on to be medically or surgically man-aged and subsequently gained weight but were under-weight at the time of referral). Power was limited in thisstudy, especially in the nonattenuated group, which con-sisted of 18 total dogs. The relatively lower number ofdogs reduced the ability to detect significant differencesbetween nonattenuated and attenuated dogs. Anexpanded retrospective study including longer-term life-long follow-up would be helpful in commenting on theability to wean from medical management as well as sur-vival; the majority of dogs in this study were maintainedon some degree of medical management and still alive atthe time of data collection.284 SPIES ET AL . 1532950x, 2024, 2, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14040 by Cochrane France, Wiley Online Library on [14/02/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseThe method of case selection may have resulted in alimiting understanding of overall prognosis and treat-ment success, as EHPSS dogs managed medically withprimary care veterinarians (and not referred) would havebeen missed. The dogs that were solely managed medi-cally in our study population appeared to be less affectedinitially. However, surgically managed dogs tended to dobetter in terms of eventual weaning from medical man-agement. Criteria dictating the weaning of medical man-agement was not standardized and not exclusivelydescribed for the majority of these dogs, which affectsour ability to correlate weaning with clinical improve-ment. Additionally, records did not clarify whether lackof weaning was associated with owner noncompliance ordue to continued clinical need.In conclusion, surgically managed dogs in this grouphad similar clinical outcomes as typical small breedEHPSS dogs, supporting pursuit of attenuation in thesedogs. Shunt configurations, though not uniformlydescribed, did not differ markedly from the typical smallbreed EHPSS dogs, though a small portion of this popula-tion had shunt configurations that are rare in small breeddogs (splenoazygos, splenonephric).1,8,9Surgical attenua-tion resulted in minimal short-term complications andreduction of medical management for the majority ofoperated dogs, and less deaths associated with shuntcomplications. Attenuation is a valid treatment option forlarger dogs with EHPSS. Similarities found in this studyto typical smaller EHPSS dogs may help to guide caseselection for surgical intervention as well as to betterinform client expectations.AUTHOR CONTRIBUTIONSSpies K, DVM, Ogden J, DVM, DACVS-SA andSterman A, DVM, DACVS-SA: Conception of the study,study design, data collection, data analysis and interpre-tation, and drafting, revision and approval of the submit-ted manuscript. Davidson J, DVM, MS, DACVS,DACVSMR, Scharf V, DVM, MS, DACVS-SA, Reyes B,DVM, Luther JK, DVM, MS, DACVS-SA, Martin L,Kudej R, PhD, DVM, DACVS-SA, Stockman T, DVM,Maloof-Jones Gallaher H, DVM, MS, DACVS-SA, BuoteNJ, DVM, DACVS-SA, Smith M, Ciepluch B, DVM,DACVS-SA, Amore R, DVM, Sherman AH, DVM, andWallace ML, DVM, MS, DACVS-SA: Medical record col-lection, case follow-up as needed, data gathering, organi-zation, and case submission, revision and approval of thesubmitted manuscript.ACKNOWLEDGMENTSThe authors thank George E. Moore for his contributionto data organization and statistical analysis. We alsothank Jennifer Kelsey for her case contribution fromVCA West Los Angeles Animal Hospital in Los Angeles,CA. We are especially grateful for the support of the Soci-ety of Veterinary Soft Tissue Surgery.CONFLICT OF INTEREST STATEMENTThe authors declare no conflict of interest related to thisreport. This includes financial conflict of interest.ORCIDValery Scharfhttps://orcid.org/0000-0002-5011-9005Nicole J. Buote https://orcid.org/0000-0003-4623-3582Mandy L. Wallace https://orcid.org/0000-0002-5286-4287

Answer 141

The objective of the current study was to establish param-eters that describe GER events in nonbrachycephalic,hospitalized dogs with no known history of gastrointesti-nal disease, using prolonged esophageal pH monitoringfollowing short total intravenous anesthesia. Based onthe results, occasional, brief, spontaneous GER events area normal feature of hospitalized, nonbrachycephalic dogswithout known gastrointestinal disease. Accordingly,transitory exposure of the esophagus to gastric acid isexpected for dogs in the hospital setting. The resultsexpand on the findings of three previous studies usingesophageal pH monitoring in smaller cohorts of dogs thatwere restricted to certain breeds or weights or by sex ofdogs, under experimental conditions.3–5In the current study, two key parameters were gener-ated that described gastroesophageal reflux in nonbrachy-cephalic dogs, in a hospital setting. Cumulative esophagealacid exposure reflects the duration that esophagus wasexposed to luminal contents with a pH less than 4 duringa set period of time and was a function of the numberand duration of GER events. Two previous studies usingpH monitoring in unsedated dogs reported cumulativeesophageal acid exposure, at a location equivalent to thedistal sensor in this study (Table4). McMahon3andKook4reported a median cumulative esophageal acidexposure of 0.1% and 0.3%, respectively. The studies byMcMahon3and Kook4were both performed under exper-imental conditions. The results of the current study simi-larly show that low cumulative esophageal acid exposurecan be expected for dogs without overt gastrointestinaldisease undergoing esophageal pH monitoring in a hospi-tal setting (Table4). In people, a distal cumulative esoph-ageal acid exposure of less than 4% reflects physiologicacid exposure, whereas >6% indicates pathologic refluxburden.9,10Previous studies have shown a significantassociation between duration of esophageal acid exposureand the surface area of esophageal metaplasia (Barrett'smucosa).11In the current cohort of dogs without overtgastrointestinal disease, the upper reference limit forcumulative distal esophageal acid exposure is 2.3%.Future prospective studies that include gross and histo-logic assessment of the esophagus would allow the occur-rence of reflux to be associated with esophagealpathology in dogs.The current study is the first to use prolongedesophageal pH monitoring with a dual sensor in unse-dated, nonbrachycephalic dogs. Esophageal pH monitor-ing with a dual sensor allowed more completeassessment of the pattern of GER during the monitor-ing period. Of the 31 dogs that had a dual sensorplaced, 12 recorded proximal GER. Each proximal GERevent represents a risk of fluid entering the oropharynxwith potential for aspiration. No expelled, productiveregurgitation was noted in any dog during the study soit is unknown whether the refluxate subsequentlyentered the oropharynx and was swallowed or wascleared via initiation of a secondary peristaltic wave.12A previous study by Appelgrein and Hosgood1pre-sented data from a cohort of 43 brachycephalic dogsundergoing esophageal pH monitoring with dual sen-soring. In that study, the median number of proximalGER events per hour was 1.9 (range 0.2 –6.8), and themedian longest proximal GER event was 9 min (range0–60 min).1In comparison, the nonbrachycephalic cohortin the current study had infrequent proximal GER events(median 0 per hour, range 0 –1), which were brief(median longest event 1 min, range 0.1 –3 min). BothTABLE 4 Median (range) cumulative distal esophageal acidexposure (%) reported by the current study and two previousstudies using esophageal pH monitoring in unsedated dogs.Paper (yearpublished)Numberof dogsCumulative esophageal acid(pH <4) exposure (%)McMahon321 0.1 (0 –3.59%)Kook47 0.3 (0 –3.1%)Current study 35 0.2 (0 –3.9%)50 NASH ET AL . 1532950x, 2024, 1, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14020 by Cochrane France, Wiley Online Library on [05/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensecohorts were monitored in the same hospital setting. Thedisparity in frequency and duration of proximal GERmay explain why expelled, productive regurgitation isseen in brachycephalic dogs.13It may also explain whyaspiration with subsequent pneumonia is frequently diag-nosed in brachycephalic dogs.2In the current study, upper reference limits for twokey parameters (number of GER events per hour andcumulative esophageal acid exposure) were generatedbased on 35 healthy dogs without gastrointestinal disease.The upper reference limits for the number of distal andproximal GER events per hour was 2.4 and 0.4, respec-tively. In the cohort of 43 brachycephalic dogs presentedby Appelgrein and Hosgood,1the median number of dis-tal and proximal GER events per hour was 3.8 (range0.9–49.4) and 1.9 (range 0.2 –6.8), respectively. Applyingthe upper reference limits generated in the current studyto the brachycephalic cohort,1the median number ofGER events per hour was above the upper referencelimit. The median cumulative distal and proximal esoph-ageal acid exposures were 6.4% (range 2.5 –36.1%) and2.8% (range 0.1 –14%), respectively, which indicates thatall 43 dogs in that study would be probable outliers com-pared to the referent population, and thereby consideredabnormal. The study by Appelgrein and Hosgood1high-lights the clinical application of esophageal pH measure-ment, used as both a diagnostic and a monitoring tool.Use of esophageal pH measurement should be encour-aged to augment clinical practice; the upper referencelimits generated in the current study can be used toobjectively identify dogs with excessive GER.The transnasal technique for probe placement hasbeen used in a previous study by Favarato5although,in that study, dogs were conscious during probe inser-tion. Favarato5reported nasal mucosal bleeding in 6/10dogs, in addition to frequent sneezing, choking andhead movements. In the current study, dogs wereplaced under a light plane of anesthesia, and the onlyadverse event recorded was minor, intermittent sneez-ing associated with the probe in situ on recovery. Inpeople, a limitation of catheter-based esophageal moni-toring systems is interference with normal daily activi-ties, such as eating;14this was not noted in the currentstudy. McMahon3used the same probe as was used inthe current study; however, the probe was placed per-cutaneously through the left lateral neck. McMahon3reported that two dogs died following iatrogenic esoph-ageal perforation and three developed a seroma at thesurgical site. Percutaneous placement is unnecessarilyinvasive, and the protocol described in the currentstudy offers veterinarians a technique for esophagealpH monitoring that is clinically applicable and lessmorbid. People are conscious while the probe isplaced.15While conscious placement would eliminateany morbidity associated with anesthesia, this wouldlikely not be well tolerated by dogs and could create astressful environment.One limitation of the current study is the possibleinclusion of some dogs with gastrointestinal disease,despite a preadmission screening protocol. The owner ofeach dog was provided a questionnaire outlining previ-ous medical history and medi cations administered. Asingle author (TN) discussed clinical signs (such asvomiting and diarrhea) that are easily observed byowners, which would indicate underlying disease. Com-prehensive exclusion of dogs with gastrointestinal dis-ease would necessitate blood and fecal testing,abdominal ultrasound, endoscopy, and possibly gastro-intestinal biopsies, which was not feasible in the currentstudy.The duration of fasting was estimated to range from12 to 18 h (median 15.5 h), assuming all dogs hadaccess to food until 10:00 p.m. the evening prior toadmission; however, the true duration of fasting foreach dog was unknown. There has recently been a shifttoward shorter periods of preanesthetic fasting prior toelective surgery in human and veterinary medicine.16Aprevious study showed the frequency of GER was sig-nificantly higher in dogs fasted for 18 h, in comparisonwith dogs fasted for 3 h, as measured using esophagealpH monitoring in dogs under general anesthesia forelective orthopedic surgery.16The period of fasting inthe current study may have affected the frequency ofGER and further examination is warranted; it is an eas-ily controlled variable should its effect on GER beverified.All dogs were fed boiled chicken, or commercial wetor dry food (Hills Pet Nutrition). In dogs, there is cur-rently no evidence to suggest that variation in macronu-trient composition influences the frequency and orduration of GER. A prospective, crossover study of 12 peo-ple undergoing esophageal pH monitoring showed thatthe mean total number of GER events was significantlylower when subjects received a low-carbohydrate (84.8 g)meal compared to a high-carbohydrate (178.8 g) meal(7.1 ± 2.3 compared to 12.7 ± 2.1) ( p=.026).17Byextrapolating data from people, it is possible that dogs feda low-carbohydrate meal (such as chicken) would haverecorded fewer GER events than those fed commercialdog food (dry matter approximately 50% carbohydrate).Based on limited, inconsistent information available fromnutritional studies in people, it is unclear how the con-tent of fat and protein would influence the frequency andduration of GER in dogs.18–20Regardless, it is likely thatmacronutrient composition would be confounded bymeal size and caloric density, as both would affect gastricNASH ET AL . 51 1532950x, 2024, 1, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/vsu.14020 by Cochrane France, Wiley Online Library on [05/01/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensedistension. Further studies that control for the potentialconfounding effect for diet may provide more informationon the potential association of diet and frequency of GER.Finally, GER events in the current study were definedas a reduction in esophageal pH to below 4. In people,concurrent impedance and pH monitoring is used tosubcategorize GER as strongly acidic GER (pH <4),superimposed acid reflux (reflux while pH < 4 during anacid-clearing interval), weakly acidic (pH nadir is 4 –7),and weakly alkaline reflux (pH >7).21In dogs, all previ-ous studies using pH monitoring have used the same def-inition of GER as the current study.1,3–5The cut off of pH4 would be consistent with strongly acidic reflux if thesame categories used in people were applied. It isunknown whether the subcategories described in peopleare relevant for dogs, as the subcategories are symptom-based in people.5|CONCLUSIONEsophageal pH monitoring offers a minimally invasive,objective means to identify the frequency and duration ofGER events. Based on the results of the current study,occasional, brief, spontaneous GER events are a normalfeature of nonbrachycephalic dogs without overt gastro-intestinal disease following short, total intravenous anes-thesia in the hospital setting. The current study providesupper reference limits for number of distal and proximalGER events per hour and distal and proximal cumulativeesophageal acid exposure, based on 35 reference subjects.Dogs undergoing esophageal pH monitoring in a similarsetting, with parameters above these upper referencelimits, have excessive GER.ACKNOWLEDGMENTSAuthor Contributions: Nash TR, BVSc (Hons), Grad-DipEd, MVetSurg: Study conception and design, acquisi-tion, analysis and interpretation of data, manuscriptpreparation and review. Hosgood GL, BVSc, MS, PhD,FACVSc, Dipl. ECVS&ACVS: Study conception anddesign, analysis and interpretation of data, manuscriptpreparation and review. Appelgrein CA, BVSc, MANCVS,GradDipEd, MVetClinStud, MVetSurg, DipECVS: Studyconception and design, manuscript review. All authorsprovided a critical review of the manuscript and endorsethe final version. All authors are aware of their respectivecontributions and have confidence in the integrity of allcontributions. Open access publishing facilitated by Mur-doch University, as part of the Wiley - Murdoch Univer-sity agreement via the Council of Australian UniversityLibrarians.CONFLICT OF INTEREST STATEMENTThe authors declare no conflict of interest.

Answer 142

FVAA is an uncommon malignancy with a limited number of cases reported in the literature. A common feature in the described cases is their clinical presenta -tion of an ill-defined caudal abdominal wall mass with or without ecchymosis, serosanguinous discharge and oedema. Leading differential diagnoses for a solitary ventral abdominal wall mass include inflammatory (eg, cellulitis, eosinophilic granuloma complex, mastitis, panniculitis and steatitis), infectious (eg, mycobacte-rium species, nocardia species or actinomyces species), trauma and other neoplastic conditions (eg, mammary gland adenocarcinoma, cutaneous lymphoma).10 Within our small number of cases, the distribution between HSA (55%) and LAS (45%) phenotypes arising from the ventral abdominal wall was similar and distinguish-ing between the two on clinical presentation alone was not possible. A definitive diagnosis of AS is usually achieved with histopathology, as was the case for all the patients in our study. Conversely, FNA cytology was only supportive of sarcoma in 1/2 of our cases, which reflects the typical behaviour of sarcomas being poorly exfoliative when minimally invasive diagnostics are attempted.5In the present cases, no pathognomonic clinicopatho -logical abnormalities were detected on routine blood sam-pling. The most common haematological abnormality, documented in 44% of cases, was a neutrophilia. Possible causes for this include tumour-associated inflammation, a paraneoplastic syndrome or in response to second-ary opportunistic infections. Paraneoplastic immune- mediated haemolytic anaemia has previously been reported in two cases of feline LAS, one of which was FVAA; however, this was not observed in any of our cases.9,11Tumour staging in our study revealed no detection of regional metastasis and a low detection of distant metas -tasis (12.5%) at presentation. Given the lack of regional lymph node sampling or subsequent extirpation, the true incidence of regional metastasis may have been under -represented. In addition, in the one case (HSA pheno-type) in which pulmonary metastases were suspected, these were not confirmed cytologically or histologically. Comparatively, the metastatic rate of previously reported feline cutaneous/subcutaneous HSA appears low and the most frequent location is the lungs.20 In a study by McAbee et al,21 no regional or distant metastasis was detected in 18 cats with cutaneous/subcutaneous HSA for which 11 underwent both thoracic radiographs and abdominal ultrasound at initial presentation. Four of these cases were described as arising from the ventral abdominal wall. Pulmonary metastasis was reported by Johannes et al20 in 3/13 cats with HSA that were known to have complete tumour staging, with two of these cases arising from cutaneous or subcutaneous tissue of an unspecified location. For the previously reported cases of FVAA with a favoured LAS phenotype, metastasis was documented in three cats, one to the inguinal lymph nodes and two had distant metastasis (pleural and peri -cardial in one and cardiac, pericardial and mediastinal in the other).10–12 Appendix 1 in the supplementary material summarises the previously reported FVAA cases in which an LAS phenotype has been assigned in the literature.In our study, with histopathology alone, four cases were diagnosed as AS, while in five cases, an LAS pheno -type was assigned. The use of IHC in our cohort was an important tool for confirmation of the tumours being of endothelial cell origin but also allowed differentiation between LAS and HSA phenotypes. In particular, two cases of LAS were reclassified as HSA, suggesting that based on histopathology alone, differentiation between phenotypes is not definitive. Based on this, it is possible that some of the previous cases of FVAA that had been assigned an LAS phenotype may be reclassified as HSA, with the addition of lymphatic specific IHC markers. Figure 4 Lymphangiosarcoma phenotype (case 4). (a) Photomicrograph with haematoxylin and eosin stain (×200 magnification). Spindle-shaped neoplastic cells formed vascular channels with the absence of intraluminal erythrocytes. (b) Neoplastic cells demonstrated moderate positive cytoplasmic staining for factor VIII (×400 magnification) confirming endothelial cell origin. (c) Nuclei of neoplastic cells were diffusely and strongly positive for PROX-1 (×400 magnification) consistent with an LAS phenotype6 Journal of Feline Medicine and Surgery Table 1 Characteristics of the study populationCase Signalment Description of primary lesionMetastasis Histological diagnosis Immunohistochemistry Phenotype after IHCTreatment(s) OutcomeFactor VIII PROX-11 9 yo FS DSH Non-ulcerated mass (5 × 3 cm) with ecchymosisN AS + – HSA S(CE) and adjuvant treatment with doxorubicin (1 mg/kg IV q3wks) and cyclophosphamide (50 mg total dose PO q3wks) for 5 cyclesDFI >580 days with routine restaging performed2 5 yo MN DSH Ulcerated mass (10 × 5 cm) discharging serosanguinous-like fluidN AS + – HSA S(IE) DFI >329 days. Remained clinically well with no evidence of local recurrence3 7 yo MN DSH Non-ulcerated mass (4.1 × 3.6 × 8.4 cm); inguinal and right hindlimb oedemaNA AS + + LAS IB; meloxicam (0.1 mg/kg PO q24h)Euthanased at 208 days owing to advanced local disease4 10 yo FS DSH Ulcerated mass (4.5 cm) with ecchymosis; discharging serosanguinous-like fluidN AS – LAS + + LAS IB NA5 10 yo FS DSH Ulcerated mass (2.0 cm); discharging serosanguinous-like fluidN AS – LAS + + LAS S(IE) with inguinal fold advancement flap; adjuvant doxorubicin (1 mg/kg IV q3wks) for 1 doseLocal recurrence at 67 days; euthanased at 97 days owing to progressive local disease and wound dehiscence6 12 yo FS DSH Ulcerated mass (7.0 × 2.3 × 3.0 cm) with ecchymosis; discharging serosanguinous-like fluidN AS – LAS – + LAS S(IE); adjuvant toceranib phosphate (2.6 mg/kg PO q24h on a Monday–Wednesday–Friday schedule)Herniation of abdominal viscera postoperatively requiring revisional surgery; local recurrence at 120 days; arrested under anaesthesia at 197 days at the time of assessing progressive local disease7 10 yo FS DSH Non-ulcerated mass (2.5 × 2.0 cm) with ecchymosisN AS – LAS + – HSA S(IE) and adjuvant doxorubicin (1 mg/kg IV q3wks) for 5 dosesLocal recurrence of a mass at 311 days; euthanased at 381 days owing to progressive local disease8 14 yo MN DLH Ulcerated mass (2.0 × 3.0 × 1.5 cm) with ecchymosis; discharging serosanguinous-like fluidY AS – LAS + – HSA IB; chlorambucil (4 mg/m2/day) and meloxicam (0.1 mg/kg PO q24h)Stable disease; PFI of 71 days; euthanased at 137 days owing to progressive local disease9 16 yo FS DSH Non-ulcerated mass (2.0 × 3.0 cm); inguinal oedemaN AS + – HSA IB; prednisolone (0.5 mg/kg PO q24h) and carboplatin (240 mg/m2 IV q3–4wks) for 3 dosesPartial response; PFI of 105 days; euthanased at 166 days owing to progressive local disease+ = positive; – = negative; AS = angiosarcoma; DFI = disease-free interval; DLH = domestic longhair; DSH = domestic shorthair; FS = female spayed; HSA = haemangiosarcoma; IB = incisional biopsy; IHC = immunohistochemistry; IV = intravenous; LAS = lymphangiosarcoma; MN = male neutered; N = no; NA = not available; PFI = progression-free interval; PO = per os; S(CE) = surgery with complete excision; S(IE) = surgery with incomplete excision; Y = yes; yo = years oldBellamy et al 7Of particular interest was that one of our cases of LAS had negative expression for factor VIII-related antigen but positive expression of PROX-1. Negative factor VIII expression has not been previously described in cases of FVAA with an LAS phenotype (see Appendix 1 in the supplementary material); however, in human literature, this has been previously reported for AS believed to have at least partial lymphatic differentiation.22The predominant challenge in the management of sar -comas in cats is local tumour control and surgical resec -tion with wide margins, where possible, is considered the mainstay treatment.5 This challenge was also apparent in our study where a high rate of incomplete excision (75%) and subsequent local tumour recurrence (60%) was observed. This is likely secondary to the type of surgery performed in most cases (ie, excisional biopsy), infil -trative behaviour of sarcomas, challenging anatomical location, primary tumour size and commonly ill-defined gross appearance of the mass. Therefore, before surgery, incisional biopsies would be recommended for improved treatment planning. Similar to our study, reported cases of feline subcutaneous HSA were also associated with high rates of incomplete excision (50–94%) and local recurrence (50–80%),19–21,24 and in one study, the median time for local recurrence was 208 days.19 However, for a subset of cases treated with aggressive surgical excision (with or without adjuvant therapies), median survival time ranged from 9 months to 4 years.21,24 Interestingly, two cases of HSA in our study experienced prolonged survival but this was not observed in any cats with an LAS phenotype. This may suggest that a subset of cats with FVAA with the HSA phenotype may have improved outcomes when treated with surgery; however, larger studies are required. Of note, for one of our cases with a HSA phenotype in which excision was incomplete and no adjuvant treatment was pursued, a good survival outcome was still observed (DFI > 329 days). Possible explanations may include challenges to accurately assess histological margins due to tissue shrinkage after excision and/or because of formalin fixation vs the destruction of residual tumour cells owing to the inflammatory response in the surgical wound or the subsequent development of tumour dormancy.25 For FVAA with an LAS pheno-type, local tumour control also posed the most significant challenge in our study with both cases, where excisional surgery was performed experiencing local recurrence at 67 and 120 days. This was also evident in 50% of cases previously reported in the literature undergoing surgical excision and with follow-up available (see Appendix 1 in the supplementary material).Regarding surgical complications, six of our cases experienced delays in wound healing; however, the majority were considered minor, with the exception of the two patients that developed visceral herniation and incomplete wound healing. Possible causes of delayed wound healing include incomplete excision and thus the possible effects of the ongoing tumour microenvironment and/or secondary infection (as detected in two cases).In humans, AS makes up less than 2% of all soft tissue sarcoma and principally affects adults (median age 60–71 years).26 Cutaneous lesions represent approximately 60% of cases and are often located on the head and neck.3 Reported rates of advanced or metastatic disease on pres-entation are in the range of 16–44% and the OST is 6–16 months.27 Radical surgery followed by adjuvant radio-therapy is currently the best treatment to achieve local control.26 The status of surgical margins and its associa -tion with outcome remains to be fully defined; however, overall clear margins tend to improve patient survival.27 The subclassification of AS based on phenotypes had pre-viously been abandoned, as most studies had concluded that AS frequently showed mixed lymphatic and blood vascular endothelial differentiation, although a subset of tumours can undergo at least partial differentiation along the lymphatic endothelial lineage.2 Furthermore, there was questionable clinical relevance as, previously, there were no specific therapies directed to tumours with blood vessel or lymphatic differentiation.2 More recently, tyrosine kinase inhibitors, such as sorafenib and pazo-panib, have been found to be beneficial in the treatment of AS in humans with LAS phenotype through inhibition of VEGF/VEGFR and/or platelet-derived growth fac-tor receptor signalling pathways.28,29 Comparatively, in cats, the role of systemic treatments for both HSA and LAS is yet to be fully defined. Adjuvant anthracycline-based treatments have significantly improved survival of canine patients with HSA; however, systematic evalu -ations are lacking in cats.30 In addition, further studies are required to assess whether LAS phenotypes would warrant alternative medical therapies to HSA. Recently, toceranib phosphate (Palladia; Zoetis) was used in a Figure 5 Kaplan–Meier plot of overall survival time for cats with haemangiosarcoma and lymphangiosarcoma phenotypes. Marks indicate time of censoring8 Journal of Feline Medicine and Surgery recurrent LAS at the level of the caudal mammary gland in a 5-year-old female neutered Boxer, which resulted in a partial response lasting beyond 3 months.31 Only one of our patients received toceranib phosphate but the cat died as a consequence of local disease progression before the efficacy of this treatment could be assessed.The limitations of this study are primarily due to its retrospective nature and limited case numbers, which is partially reflective of the rarity of this condition. In addi -tion, there was heterogeneity in treatment and patient management, which was clinician-dependent and likely acts as a confounding bias. Finally, the treatment land-scape would have differed over the 15-year period in which cases were retrieved; for example, the introduction of small molecule inhibitors such as toceranib phosphate (Palladia; Zoetis).ConclusionsThe aim of this retrospective study was to describe the clinical characteristics, treatments and outcome of cases of FVAA. This is a rare, locally aggressive neoplasm associated with a guarded prognosis in most cases. The main challenge is local disease control with a high risk for incomplete excision, local tumour recurrence and post-operative complications. Histopathology is a cornerstone in achieving a definitive diagnosis; however, IHC may be used to differentiate between HSA and LAS phenotypes. It remains to be defined whether confirming this differ -entiation in feline AS is prognostic alongside whether dif-ferent treatment modalities may be pursued in the future, depending on the phenotype.Author note These findings were presented at the British Small Animal Veterinary Association 2023 Annual Congress clinical abstract stream as a 12-minute oral presentation.Supplementary material The following file is available as supplementary material:Appendix 1: Characteristics of previously published cases of FVAA (LAS phenotype assigned).

Answer 143

The results of this study demonstrate that each biomaterialproduced highly accurate replicas, with mean post-steriliza-tion dimensional changes for all materials and sterilizationmethods less than or equal to 0.05 mm. Despite these accu-rate results, signi ﬁcant differences were noted; therefore,part of the null hypothesis was rejected.Some dimensional errors due to fabrication were noted.Indeed, pre-sterilization measurements revealed that per-centage change was smaller for linear measurements(maximum of 0.2% change vs. a maximum of 1% for thethickness measurements). However, this still re ﬂects high-ly accurate replicas across resin types. Interestingly, theB Wr e s i nf a i l e do ns e v e r a ls a m p l e st oa c c u r a t e l yp r i n tnegative features, one of the measures of accuracy.32Allother materials printed legible labels. While this wouldnot have a clinical effect, it suggests that the BW resin maybe a less desirable choice for surgeons considering theobjective results of dimensional analysis for this material.Additionally, the majority of resins trended toward sizeover-estimation of printed replicas, which is different fromother desktop printers and non-biocompatible resins.6Other post-sterilization dimensional studies do not direct-ly report on under or over-estimation of measurements,which would be useful information for guide and instru-ment design. Indeed, while the magnitude of such changesis not likely to be a clinically relevant ﬁnding, it could be animportant consideration when selecting tolerances in pa-tient-speci ﬁc guides.Overall, the BA was subjectively assessed as being themost consistent resin. Out of nine measurements, the BAmaterial produced replicas which over-estimated ﬁve, un-der-estimated one and was an exact match for three of these,.both before and after sterilization. Conversely, the BW resinwas most affected by sterilization. Indeed, before steriliza-tion this resin produced replicas with two over-estimatedmeasurements, six under-estimated and one exact match.Following sterilization, these became two, one and six re-spectively. Furthermore, all tube and thickness dimensionsshowed an increase in size, which should be consideredwhen designing guides and models. Given these results,one could suggest that the BA resin would be most suitablefor institutions using a variety of sterilization protocols.Importantly, the largest absolute difference noted in a singlesample for any material or sterilization method was0.17 mm. This is notably smaller than an earlier report wherethe largest recorded absolute variation was 1 mm usingdesktop printers.6This may be, in part, due to the differencein model pro ﬁle between studies. In the current investiga-tion, measurements were comprised of simple geometricshapes, whereas the previous report evaluated a humeralreplica with complex geometry. Printer accuracy may beimproved with less intricate parts. Additionally, since thematerials evaluated in the current study were not directlycompared with the resin used in a previous study,6thepossibility of differences in material accuracy cannot beexcluded.When comparing steam and hydrogen peroxide gasmethods, there was no difference in accuracy. However,ethylene oxide overall showed the largest dimensionalchanges for some materials. Therefore, the second part ofour null hypothesis was partially accepted. Of the biocom-patible materials evaluated, the only two unaffected bysterilization method were the BA and BB resins. Consideringthe pre-sterilization observations regarding the high accu-racy and consistency of BA replicas, this ﬁnding furthersupports the use of BA for creating patient guides in clinicalcases. Additionally, given the concerns of ethylene toxici-ty,18ﬁndings of this study may support the use of eithersteam or peroxide gas to sterilize printed guides or instru-mentation. Indeed, previous apprehensions of using steamsterilization for moisture-sensitive materials15do not seemto be an issue for the biocompatible materials printed withthe Form 3B desktop printer. Finally, from a clinical stand-point, these ﬁndings are relevant when considering 3Dprinted guide use because the two most accurate methodsof sterilization (steam and peroxide gas) are also thequickest (20 and 49 minutes respectively). Additionally,steam is inexpensive and more accessible for many hospi-tals.12This means that surgeons could theoretically create apatient-speci ﬁc guide from a CT scan, print and sterilize itfor surgery the same or following day, which may beparticularly useful for fracture ﬁxation applications. Theuse of patient-speci ﬁc instrumentation in joint replacementsurgery could also become more mainstream, given thecombined accuracy results from the biocompatible resinsreported here and condylar accuracy results from a previ-ous study.6While not directly related to accuracy, printing times andresin volumes should be a consideration in pre-operativeplanning. Indeed, printing times will affect the rapidity withwhich guides can be created or surgical planning can beperformed. Ultimately, this will determine when a case canbe taken to surgery. Less concerning is the volume of resinrequired to complete the print. However, this becomesimportant when establishing a charging protocol for clinicalcases. Variation in costs between resins is dependent on theadditives for each material ’s composition, research anddevelopment costs, certi ﬁcations and the supply chain (pri-vate communication with Formlabs). Since the results of thisstudy indicate the BA resin to be overall the most accurateand unaffected by sterilization, in addition to most afford-able, one may suggest this would be the resin of choice whencreating patient guides.Numerous factors have been shown to affect 3D printaccuracy including model size, printer and material type,support materials and model orientation on the platform(additional factors such as imaging acquisition were notapplicable in this study).27,33 –36When considering customguide function, its interface with the surface of the patientshould ﬁt as accurately as possible to prevent deleteriousmovement during surgery. Accordingly, surgeons shouldorient this surface away from the build platform (andthereby supports) to minimize inaccuracies.27While theideal orientation angle has not been reported, the authortypically places parts anywhere from a 25 to 60 degreeangle relative to the build platform (depending on thepart) to maximize print success and minimize warping,particularly with lengthy specimens. Indeed, van Dal notedparts placed at 0 degrees had more deformations thanthose placed at 90 degrees.27Causes of warping or failedprints vary based on printer type, but for stereolithogra-phy machines these are typically the result of ‘cupping ’inhollow regions that act as a suction cup and trap air whileprinting.Some study limitations should be acknowledged. First,specimen blinding was not possible given the study design,and human error is possible. Second, this study evaluatedbiocompatible resins from one company using one desktopprinter. Consequently, these results should not be extrapo-lated to other materials or printers. Finally, we used a simplemethod to obtain measurements which is similar to otherpublished reports.6,35 –37Other methods have been de-scribed38and future evaluations could consider use of thesein their analysis.This study demonstrated that mock surgical guides 3Dprinted in biocompatible materials using the Formlabs 3Bdesktop printer were highly accurate, with mean dimension-al change following sterilization less than or equal to0.05 mm. Furthermore, this study reports on two newlyreleased biomaterials, the BW and BB resins and comparessterilization methods across numerous materials. Addition-ally, these results indicate that the BA and BB materialsretained their dimensions post-sterilization. This suggeststhat surgeons should feel con ﬁdent using such materials tocreate patient-speci ﬁc instrumentation for use in clinicalpatients..

Answer 144

The use of rigid endoscopy in the management of acute OSI in dogs was evaluated in 46 dogs. This produced an excellent long- term outcome in 95.0% of cases and there was a low rate of cervical abscessation. This indicates that rigid endoscopy can be used successfully to manage acute OSI in dogs.Previous studies recommended ventral cervical surgical explo -ration as the treatment of choice in acute OSIs (Baker 1972 , White & Lane 1988 , Griffiths et al. 2000 , Doran et al. 2008 , Nicholson et al. 2008 ). However, in the authors’ study, rigid endoscopy functioned as both a diagnostic and therapeutic tech -nique. Case selection is important as patients with very shallow OSI injuries, oesophageal tears requiring primary repair, OSI tracts where the caudal extent cannot be reached by endoscopy, and patients with extension of injuries into the thorax may not be suitable for endoscopic treatment alone. However, even in the four cases that required open surgery, rigid endoscopy was useful as a diagnostic tool and was used together with surgery to remove foreign material and to lavage OSI tracts. In one of the two dogs that developed cervical abscessation after initial endoscopy, it was possible to identify retained foreign material using repeat endos -copy and to achieve resolution without open surgery.Use of rigid endoscopy requires an open tract, which lim -its its use to acute OSIs rather than chronic OSIs (Robinson et al. 2014 ). In the present study, 23.9% of dogs were presented between 3 and 7 days after trauma and a patent tract allowing endoscopy was still present. The length of the tract can limit the utility of rigid endoscopy in the treatment of acute OSI if it is longer than the working length of the endoscope, although it is still valuable as a diagnostic tool. For example, in one patient in the current study a stick had penetrated the oropharynx and tracked dorsal to the oesophagus, terminating subcutaneously over the right shoulder. Endoscopy provided information about the location of the injury and the presence of foreign material, even though surgical removal of the stick fragment was required.When comparing lesion location, Doran et al. (2008 ) reported an oropharyngeal injury in 27 out of 41 dogs (65.9%) and an oesophageal injury in the remaining 14 out of 41 dogs (34.1%), whereas Robinson et al. (2014 ) and Griffiths et al. (2000 ) reported exclusively oropharyngeal injuries. In the present study, 42 out of 46 dogs (91.3%) had an oropharyngeal injury and the remaining 4 (8.7%) had oesophageal injuries. Case selection for rigid endoscopy may have biased the study cohort towards oro -pharyngeal injuries in Robinson et al. (2014 ) and the present study because rigid endoscopy is likely to be more useful in these cases. Interestingly, only one out of the four dogs in the present study that had oesophageal injury required open surgery. This may reflect a tendency towards the use of oesophageal bypass for cranial oesophageal tears rather than open surgery, or simply dif -ferences in the study groups. If oesophageal injury is suspected, flexible endoscopy or sigmoidoscopy (for more cranial injuries) should be used to evaluate any lesions and thus decide whether oesophageal bypass or open surgery is required.The rate of cervical emphysema in this study (65.8% of dogs that had pre- endoscopy radiographs and/or CT scan) is lower than that of Doran et al. (2008 ), in which 34 of 41 dogs (82.9%) with acute OSI had cervical emphysema, but similar to that of Robinson et al. (2014 ) in which 3 out of 5 dogs (60.0%) that had pre- endoscopy imaging had cervical emphysema. Robinson et al. (2014 ) summarise the limitations of the recommendation by Doran et al. (2008 ) to perform exploratory surgery based on the presence of cervical emphysema: only 11 out of 32 dogs (34.4%) had a piece of wood retrieved during open surgery despite all these dogs having cervical emphysema on radiographs, and one patient with negative radiographic findings had a wooden foreign body retrieved 3 months after initial presentation. Compared to the false negatives seen with radiography alone, endoscopy of OSI tracts appears to be an accurate indicator of the presence or absence of foreign material, with only two out of 46 dogs (4.3%) in the current study having retained foreign material after endoscopy. The use of endoscopy in patients with negative radio - 17485827, 2023, 10, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jsap.13642 by Vetagro Sup Aef, Wiley Online Library on [19/10/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseA. Kilduff- T aylor and S. J. BainesJournal of Small Animal Practice • Vol 64 • October 2023 • © 2023 British Small Animal Veterinary Association. 640graphic findings may help to minimise progression to chronic abscessation by preventing inappropriate conservative manage -ment (Robinson et al. 2014 ).While the focus of this study was on acute OSIs managed with rigid endoscopy, the entire surveyed population encompassed both acute and chronic cases. Within this population, the pro -portion of acute OSIs was (66/86, 76.7%). This was higher than previous studies which reported nine of 50 (18.0%) (Griffiths et al. 2000 ) and 15 of 65 (23.1%) (White & Lane 1988 ) acute cases. This shift could represent an increase in early referral of cases during the acute phase due to better primary care veteri -nary surgeon education and an increased proportion of witnessed or recognised incidents. Both these previous reports describe patients with acute OSI with inadequate initial management, leading to chronic abscessation (White & Lane 1988 , Griffiths et al. 2000 ). Griffiths et al. (2000 ) describe clinical resolution in only 62.1% of chronic cases compared to 100.0% in acute cases. White & Lane ( 1988 ) report clinical resolution in 88.0% of chronic cases compared to 73.3% in acute cases. Again, this dis -parity could be explained by the difference in the proportion of acute and chronic cases presented in the 1980s, with acute cases only being referred if the clinical signs were severe, compared to more recently. In fact, acute cases were reported to be much more severe than the chronic cases in White & Lane ( 1988 ) and the follow- up period was not defined. These studies suggest that OSIs should be managed appropriately as soon after the trauma as possible. Patients with chronic OSIs generally require ventral cervical surgical exploration which may result in increased mor -bidity.CT has been increasingly used in the study cohort. From 2010 to 2015 only four of 18 (22.2%) dogs had a CT scan whereas from 2016 to 2020 CT was performed in 17 of 28 (60.7%) dogs. This may be due to the increased awareness and motiva -tion to use this modality to provide information that may show that surgery is indicated ( e.g. presence of foreign material in the neck) or that surgery may not be needed ( e.g. absence of foreign material). In this study, CT was able to detect the presence of a stick foreign body in six of nine (66.7%) dogs that had for -eign material removed at endoscopy. Therefore, the sensitivity of CT in detecting stick foreign material is not sufficient to rely on it alone. Endoscopy is recommended to examine the site of injury and to remove small pieces of foreign material that cannot be detected on CT. The size of stick fragments not detected by CT scan was 5 mm or less in this group. There was also one dog where a stick fragment 15 mm in length was missed by both CT and endoscopy. This was thought to be due to gas accumulation and lack of contrast enhancement of the area during the acute phase of the OSI.The majority of complications during hospitalisation were gastrointestinal signs such as regurgitation or vomiting. These signs are common as sequelae to general anaesthesia and use of opioid drugs (Torrente et al. 2017 ) as well as injury and swell -ing of the pharynx and neck. All these signs were temporary and resolved with supportive treatment. Major complications before discharge were related to incomplete removal of foreign mate -rial in one out of three cases. The case that was euthanased was severely affected and involved penetration of the thoracic cavity as well as excessive pharyngeal swelling.Complications after discharge all occurred within 20 days of the discharge date. Clinical signs after discharge such as change in voice, and coughing and choking when drinking were similar to those reported by Doran et al. (2008 ). The coughing or chok -ing is likely to be due to alteration of the normal anatomy or function of the oropharynx. The dog with major complications post discharge had typical signs of onset of chronic OSI and for -eign material was found to still be present.The use of rigid endoscopy in the management of acute OSIs is a safe technique that allows direct visualisation of OSI tracts and can be the sole means by which acute OSIs are treated for most patients. Therefore, the use of rigid endoscopy in the diag -nostic and treatment plan for acute OSIs is recommended. The main concern about the use of endoscopy is that endoscopic lavage has the potential to drive particles of foreign material and bacteria into adjacent tissues (Robinson et al. 2014 ). However low- pressure gravity- fed lavage was used in all cases in this study and the low rate of subsequent cervical abscessation suggests that this is not a major concern.The use of rigid endoscopy to treat acute OSI is less invasive than open surgery and is likely to result in shorter times to dis -charge (Robinson et al. 2014 ). Future research could be directed at evaluating the combined usage of various imaging modalities with rigid endoscopy, including radiography, ultrasonography, CT and MRI.A limitation of the study is the lack of consistency in pre- endoscopy imaging techniques used due to its retrospective nature. However, it is still recommended to perform initial survey radio -graphs of the cervical and thoracic regions during initial investiga -tion of known or presumed acute OSI. Other limitations of this retrospective study were its dependence on the accuracy and com -pleteness of medical records and the small study cohort. Record -ing of complications post discharge and long- term follow- up were dependent on the accuracy of referring vets’ medical records and owners’ recollections, creating the potential for underestimation of complications. However, it is possible to use the absence of cervical abscessation on the clinical history as evidence that pro -gression to chronic OSI is unlikely to have occurred.Endoscopy was carried out by several different surgeons and thus decision- making regarding case management was subject to individual surgeon variability. Another limitation includes the cost of the equipment and technical expertise required to use it. The study cohort comprised only referred patients, so there may be bias towards more severely affected animals as less severely affected patients may have been managed at the primary care level. Conversely, the selection of patients that had rigid endoscopy of an OSI wound may have biased the study cohort towards patients with less severe injury as some patients requiring oesophageal endoscopy or open surgery may have been more severely affected.Long- term outcomes in dogs with acute OSI treated with rigid endoscopy are excellent. In the small number of cases where open surgery is still performed, rigid endoscopy can be useful as a diagnostic tool. Progression of endoscopically treated acute OSIs to chronic OSIs is rare. The presence of cervical emphysema on 17485827, 2023, 10, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/jsap.13642 by Vetagro Sup Aef, Wiley Online Library on [19/10/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons LicenseEndoscopy of acute oropharyngeal stick injuriesJournal of Small Animal Practice • Vol 64 • October 2023 • © 2023 British Small Animal Veterinary Association. 641 radiographs should not be used alone as an indicator for open sur -gery and all acute OSIs should have rigid endoscopy performed.Conflict of interestNone of the authors of this article has a financial or personal relationship with other people or organisations that could inap -propriately influence or bias the content of the paper.Author contributionsA Kilduff - Taylor: Conceptualization (equal); data curation (equal); formal analysis (equal); investigation (equal); method -ology (equal); project administration (equal); resources (equal); supervision (supporting); validation (equal); visualization (equal); writing – original draft (equal); writing – review and editing (equal). Stephen J. Baines: Conceptualization (equal); data cura -tion (equal); formal analysis (equal); investigation (equal); meth -odology (equal); project administration (equal); resources (equal); supervision (lead); validation (equal); visualization (equal); writ -ing – original draft (equal); writing – review and editing (equal).

Answer 145

The current study demonstrates that measurements of ALOand version angle using 3D models based on CT data arerepeatable and offer a practic al approa ch to quantifying theorientation of the acetabulum. The morphological data maybe helpful in better de ﬁning optimal acetabular cup orienta-tion, which is crucial in preventing postoperative luxation.4While the optimal cup position has been de ﬁned by Bio-Medtrix (Whippany, New Jersey, United S tates) as an ALO of45 degrees and version angle between 15 and25 degrees,10,11this is a rather subjective assessment andin some dogs these angles may be imprecise and contributeto hip luxation. Therefore, objective, patient-speci ﬁcm e a -surement of native acetabular geometry may allow thesurgeon to improve cup positioning and reduce the overallrisk for luxation.In this study, the measurements of acetabular geometryon 3D models showed good repeatability with a low intra-and inter-observer variability, and this allowed us to acceptourﬁrst hypothesis. Similar ﬁndings were noted by Leasureand colleagues18who con ﬁrmed the low variability in meas-urements of ALO and version angle when CT images wereused to measure acetabular cup position in dogs. Anotherhuman study, by Park and colleagues, demonstrated that 3Dmeasurements are reliable for evaluating acetabular orien-tation and more consistent measurements were obtainedusing 3D bone models.19Similarly, Sariali and colleaguesreported that the use of CT scans for THR preoperativeplanning results in greater accu racy than two-dimensionalpreoperative planning,20aﬁnding that has since been alsosupported by results from other published studies.21–24The results for ALO and version angle were similar to theseobtained in a focused study of 13 Labrador Retrievers by Wu andFig. 2 Acetabular geometry was de ﬁned by marking triangles on the lunate surface of the acetabulum (A), de ﬁning a best- ﬁt sphere (B) and thencalculating the centre of the sphere (C)..colleagues.25Additionally, measurements of left and rightacetabula were not signi ﬁcantly different in our study, whichcorroborates the ﬁndings from Wu ’s study. In the current studythe mean ALO was 42.6 degrees for the left acetabulum and43.1 degrees for the right acetabulum, compared with meanALO of 40.5 degrees in the earlier publication. Our mean versionangles for the right and left acetabula were 27.51 and26.85 degrees respectively, which was similar to the27.7 degrees reported by Wu and colleagues.25However,the recommended angles for the position of acetabular cupin commercial THR system are slightly different –higher forALO and lower for version angle.10,26Therefore, our secondhypothesis was also supported. It has been reported thattoo high an ALO increases the risk of hip luxation, so it isrecommended to insert an a cetabular compo nent at lowerangle, since it may prevent luxation.4Some acetabula in ourstudy, however, demonstrated more than 10 degrees differ-ence between the angles measured using this work ﬂowFig. 3 Acetabular orientation was assessed by ﬁrst marking triangles along the cranial and caudal aspects of the ventral acetabulum (A) and thenestablishing a best- ﬁt plane to these voxels (B). The acetabular orientation plane was de ﬁned as a plane that was perpendicular to both the ventralacetabular plane and the dorsal pelvic plane, and that passed through the centre point of the acetabulum (C)..(ALO and version angle) and those recommended by man-ufacturers. These ﬁndings highlight the potential for angu-lar mismatch between the native acetabulum in dogs andthe manufacturer ’s recommendations for acetabular cupplacement. This discrepancy needs to be considered whenpositioning the acetabular component.Different values between manufacturer ’s recommenda-tion and those reported from the current study may re ﬂectour previous reliance on radiography rather than CT formeasurement of acetabular geometry and cup positioning.When using CT data and 3D reconstructed pelvic models formeasurement of acetabular cup position, pelvic rotation andtilt are controlled by the operator,27while radiography doesnot account for the pelvic tilt and rotation. This may increasevariability between measurements.28For this reason, idealpositioning of the patient for radiographs is critical to beingable to obtain accurate angles and to avoid discrepancies inmeasurements.Our study population consisted of 27 dogs of 18 differentbreeds, as compared with the study of 13 dogs from a singlebreed (Labrador Retrievers) by Wu and colleagues.25Thebreed variability corresponds better with the real-life situa-tion in which a variety of pure- and cross-bred dogs arepresented for THR. Although this larger and more heteroge-nous sample of breeds improves the clinical relevance of thedata, a much larger study is needed to make de ﬁnitiverecommendations regarding the true extent of variation inALO and version angles in dogs. Notwithstanding the limita-tion of sample size, this study demonstrates that althoughthe mean values for acetabular alignment were generallyconsistent with clinical THR guidelines, some dogs in thisstudy had more extreme values, and there was a wide rangeof angles across different breeds. Using a standard set ofrecommended angles across all breeds of dogs may lead toincorrect cup placement and an increased risk of postopera-tive complications such as luxation.The measurements reported in this study were based onthe use of just four anatomical landmarks –the cranial dorsaliliac spines and the ischial tuberosities, bilaterally. Weselected these speci ﬁc landmarks because they are widelydistributed across the four corners of the ‘pelvic box ’and arepalpable through the skin intraoperatively, providing a real-istic option for intraoperative surgical navigation. Similarobservations were made by Leasure and colleagues.18Studies from human medicine suggest that there are somedifferences in hip morphometry between ethnic groups.29Ina veterinary setting, breed-related differences have also beendescribed among large-breed dogs. For example, St. Bernardsand Bernese Mountain dogs have relatively deep acetabula ascompared with Labrador Retrievers and Boxers. In contrast,Labrador Retrievers and Boxers had shallow and relativelyopen acetabula.30A similar comparison between two small-breed dogs, the Shih Tzu and the Maltese, showed that theShih Tzu acetabulum was deeper and wider than that of theMaltese.31Such variety in acetabular morphometry betweenbreeds may have an impact on acetabular measurements andsurgical planning for THR, so further investigations areneeded to verify it.In humans, differences have been demonstrated betweenmale and female hip joints. It has been reported that femaleshave relatively greater acetabular depth, increased acetabu-lar version and smaller femoral heads,32,33while femoraloffset is greater in males.33Interestingly, despite theseanatomical differences, the same THR implant systems areused successfully in both sexes.34Less is known about sex-related difference in acetabular geometry in dogs. In small-breed dogs, sex was identi ﬁed as a variable that impactedacetabular width and depth, but acetabular index measure-ments were similar in the two sexes, suggesting that theiracetabula are shaped similarly.31Currently, it is unclearwhether sex-related variation in canine acetabular mor-phometry is suf ﬁcient to impact recommendations for opti-mum component positioning in THR.The primary limitation of this study is that all the dogsincluded in this study had normal hip joints without visiblesigns of pathology. Therefore, the results may vary in dogswith dysplastic hip joints. We used visual (subjective) esti-mates of anatomical landmarks, the identi ﬁcation of whichFig. 4 The version angle was measured between the acetabularorientation plane and the transverse plane (A). The angle of lateralopening was calculated by measuring the angle formed between thebest ﬁt plane to the ventral acetabulum and the median plane (B),then subtracting this from 90 degrees..will undoubtedly be subject to some intrinsic error. Never-theless, based on our results, the method of de ﬁning planesand angles measurement appears feasible and repeatable.Further work is needed to compare the outcome of acetabu-lar component placement in dogs with normal hips and dogswith hip disease. A much larger sample size will be needed toestablish reliable reference ranges and to allow for breed-to-breed comparisons of these measurements.ConclusionsMeasurements of the ALO and version angle on 3D in-silicomodels of the canine pelvis are feasible and repeatable. Thesedata may be used to better de ﬁne the optimal placement ofthe acetabular component in THR surgery, leading to areduced risk of postoperative complications such as hipluxation. Patient-speci ﬁc morphometric data and the abilityto obtain accurate and reproducible measurements alsoestablish the possibility of combining in-silico planningwith intra-operative surgical navigation, further improvingthe surgeon ’s ability to ensure correct placement of theacetabular components in dogs undergoing THR surgery.

Answer 146

Screw loosening was observed in 3/20 of our cases atradiographic follow-up, representing a higher incidencethan the previously reported rate of 0 to 8% in feline iliacfracture repair with locking construct,10,14but lower thanthat in nonlocking lateral plating of feline ilial fractures.4,7Previously, it has been suggested that the narrow width ofthe feline ilium results in insuf ﬁcient screw purchase andconsequently will predispose to screw loosening when alateral plating technique is used.4It is recommended that when using SOP plates, three to fourscrews and ﬁve to six cortices should be engaged on each sideof the fracture.22Ideally, three bicortical screws on either sideof the fracture should be placed.22While adding monocorticalscrews to the construct will greatly enhance the fatigue life of alocking construct, the use of bicortical screws is consideredessential for the ilium.8Failure to adhere to the recommen-dations for SOP application probably contributed to screw andconstruct loosening in these three cases.Cantilever forces are the most relevant forces acting onimplants applied to the lateral aspect of the pelvis.8Screwloosening, other than screw breakage, is the most commonmechanism of failure in this anatomical area.27Anex vivostudy28demonstrated that the SOP system has similar resis-tance to cantilever forces when compared with other lockingsystems, although cyclic loading was not tested in this publi-cation. Screw insertion torque does not seem to affect thescrew pullout resistance. However, the use of cortical screws(as used with SOP plates) that have a wider thread pitchcompared with locking screws might reduce the screw pulloutresistance in a thin bone cortex.29Cyclic cantilever forcesexperienced during weight bearing might exceed the screwthread/bone friction forces, leading to screw loosening.30.Screw breakage was seen in one case and can be explained bycyclical loading on the base of the screw shaft due to thedifference in stiffness between the screw and the plate.30As described in the “surgical technique, ”adjunct ﬁxationwas used in 9 of 20 cases, while the SOP plate alone was usedin 11 of 20 cases. This was a limitation of our study as itintroduced a variation in our osteosynthesis construct. Inmost cases, the adjunctive ﬁxation was used to aid initialreduction of the fracture, when possible, depending on thefracture con ﬁguration. The small number of cases did notallow statistical assessment of the impact of adjunctiveﬁxation on the incidence of screw loosening.Assessment of the fracture reduction can be challengingwith pelvic fractures due to the complex three- dimensionalshape of this structure. The use of sacral index was chosen toobtain a more objective measurement of the fracture reduc-tion and the stability of the ﬁxation at follow-up radiographs.Pelvic canal narrowing was identi ﬁed by follow-up radio-graphs in 80% of the cases. A 4.2% reduction in the sacralindex was noticed at follow-up radiographs in all assessedpatients, similar to previously published data.10Only onecase in our study developed implant failure; however, nomajor loss of reduction was noticed in that patient. There-fore, correlation between implant failure and changes in thesacral index cannot be statistically analyzed in our study. Ourstudy has signi ﬁcant limitations in the assessment of thesacral index due to the lack of standardization in the radio-graphic positioning. Several follow-up radiographs wereperformed by referring veterinary surgeons and did notperfectly match the patient position evident in the postop-erative images. We speculate that even minimal rotation ofthe pelvis during the ventrodorsal radiographic assessmentwould lead to changes in the sacral index due to the differentradiographic appearance of both sacral width and pelviccanal. The retrospective nature of the study did not allowfor standardization of this parameter. For the same reason,assessment of possible plate bending was not possible.Pelvic fractures usually result from high-energy trauma,which very often leads to multiple injuries. In our study, theincidence of 95% concurrent pelvic injuries was similar to aprevious study that reported multiple pelvic fractures in allthe patients.14There was no correlation between otherpelvic injuries and the frequency of screw loosening at thetime of postoperative radiographic evaluation in our study.Sacroiliac reduction was lost in four cases, of which two casesexperienced screw loosening. Both cases had monocorticalscrews placed: one (case 19) had no repair of the sacroiliacluxation, while the second (case 18) had a repair with screwsshorter than the minimum length required of 60% of thesacral body width.31This was likely responsible for thesacroiliac screw loosening. However, the displacement ofthe sacroiliac repair was minimal. Any in ﬂuence of contra-lateral sacroiliac instability on loosening of the SOP screwscan only be speculated.Complications related to the trochanteric osteotomy per-formed were evident in six of our cases, with a good overalloutcome. This is similar to what has previously beenreported.32One patient developed signs of pelvic limb paresthesia onthe operated limb. Explantation of the SOP plate resolved theclinical signs. We speculate that this patient might havedeveloped sciatic neuritis as a result of the presence of thebulky metal implants ventromedially to the sciatic nerve inthe ischiatic region.All our patients achieved excellent functional outcomeswith very low pain scores postoperatively. These results aresimilar or superior to previously reported outcomes4,5al-though the different scoring method and follow-ups make adirect comparison less accurate.Considering the implant failure by screw pullout in cases 8(►Fig. 3 ) and 18, which were treated with a short (six-hole)plate, a decision was made to apply a longer SOP plate forsubsequent caudal ilial fractures to reduce the risk of screwpullout. No screw loosening was seen in these cases.Fig. 3 From left to right: Initial fracture repair, failure of the repair two d ays postoperatively and revision surgery showing the SOP applied to theischium to increase screw purc hase in the caudal fragment..Our work has several limitations, in particular the smallnumber of cases and the retrospective nature of the study.Considering the retrospective nature of the study, the applica-tion of the plate was at the surgeons ’discretion. All measure-ments and radiographic assessments were taken by a singleobserver, potentially leading to bias. Malpositioning wouldalso have affected the calculation of the sacral indices. Also, theradiographs in this study were not calibrated.This study shows that the SOP system is a suitable optionfor the repair of pelvic fractures in the cat, although screwloosening was higher than what is published for the otherlocking systems.14Despite this, postoperative pelvic canalnarrowing was only mild, and clinical outcomes were good.

Answer 147

This study was the first to report the long-term outcomes associated with performing the modified closed anal sacculectomy technique for anal sac neoplasia. Before this, only 1 study9 had reported outcomes associated with the procedure, but clini -cal follow-up was a minimum of 30 days, which limits its utility for predicting long-term outcomes associated with the modified procedure. The afore -mentioned study highlighted several short-term advantages to performing the procedure, including controlled manipulation of tissue during dissection, minimal manipulation of adjacent soft tissue, and full excision of the gland and its associated duct.9 This study found no long-term advantage to per -forming the modified technique as opposed to the traditional technique, with respect to complication rate or local recurrence.AGASACA commonly occurs in middle-aged to older dogs with a median age of 9 to 11.5 years of age (range, 5 to 15 years).2,3,9,14 The median age of this study population (10.2 years) is consistent with previ -ously reported age ranges. While early studies sug -gested an increased proportion of neutered female dogs affected with AGASACA, sex and neuter status are no longer considered risk factors for the incidence of AGASACA.2,3,14–16 Neutered males were largely overrepresented (80%) in the current study popula -tion. A prior study15 documented that neutered males are more commonly affected than intact males, sug -gesting that the loss of hormones is associated with an increased incidence of neoplastic disease. A larger cohort of dogs with AGASACA needs to be examined to see whether this sexual dimorphism exists.A closed anal sacculectomy technique is the rec -ommended standard of surgical care because dogs are 13.76 times more likely to develop long-term complications following open anal sacculectomy.8 A prior study9 presented a modified technique for the closed anal sacculectomy and concluded that the pro -cedure was well tolerated in dogs. In this study, the traditional and modified techniques were compared to determine whether one method provided lower complication rates compared to the other. Previously, intra- and postoperative complication rates for the traditional closed anal sacculectomy procedure have been reported as low as 1.8% and as high as 20%.3,4,8,17 In this study, intraoperative and postoperative com -plications were reported in 12.7% and 21.8% of dogs that underwent the traditional approach. The intra -operative and postoperative complication rates were similarly moderate in dogs that underwent the modi -fied approach (8.6% and 14.3%). No significant differ -ence in complication rates between the 2 groups was found. With either technique, the anal sacculectomy procedure is considered a contaminated one due to the incision’s proximity to the rectum. The radial inci -sion required for the modified approach is generally closer to the rectum than the circumferential inac -tion used when performing the traditional approach. Despite this increased risk of infection, the modified group did not have higher surgical dehiscence or in -fection rates than the traditional group. A theoretical complication associated with performing the modi -fied technique is increased external anal sphincter in -cision size secondary to duct removal. This ultimately was not the case in this group of dogs, as none of them were reported to experience postoperative fe -cal incontinence. Several dogs in this study suffered adverse events secondary to either anesthesia, a previously diagnosed comorbidity, or an additional surgical procedure performed during the same an -esthetic event. A prospective study is warranted to reassess measurable outcomes (ie, surgery time and intraoperative and postoperative complication inci -dence) when anal sacculectomy is the only surgical procedure performed.The goal of anal sacculectomy for a neoplastic disease is to provide local control of the disease.3,17–19 Brought to you by Vetagro Sup Campus Vet De Lyon Biblotheque | Unauthenticated | Downloaded 11/03/23 06:54 AM UTC6 In this study, there was no advantage concerning lo -cal recurrence, metastasis, or survival with the modi -fied closed anal sacculectomy technique. Prior studies have shown recurrence rates of 5% to 21% with the tra -ditional closed anal sacculectomy procedure.9,19,20 As the modified and traditional closed anal sacculectomy procedures are both marginal excision procedures, the lack of difference in local recurrence between the 2 groups is not surprising. This study would support the idea that leaving a portion of the duct behind when performing the traditional approach does not lead to an increased recurrence rate. Complete removal of the duct did not increase survival time despite achieving larger surgical margins.In this study, the assessment of the effect of ad -juvant treatment on survival outcomes was limited due to the variations in disease burden and manage -ment and the difference in the standard of care be -tween the 2 participating institutions. Three dogs in the traditional closed group had documented meta -static disease distant to regional nodes at diagnosis but were included in the analysis. Not all dogs in this study had owners that pursued adjuvant therapy. Additionally, not all dogs that had evidence of pro -gressive metastatic disease pursued additional treat -ment. These factors could alter the metastasis rates and median survival time between study participants and should be strongly considered when interpret -ing differences in long-term outcomes between the 2 treatment groups.Aside from variations in disease burden and management among dogs, other limitations existed within the current study. Only 90 dogs were identified for enrollment. A study with a larger cohort of dogs with increased statistical power could potentially identify a smaller statistical significance between the groups. The lack of longer-term formal veterinary follow-up for every dog in this study could have in -fluenced recurrence and metastasis rates. About half of the dogs in this study population lacked clinical follow-up at the institution where surgery was per -formed, and a follow-up call to the owner or refer -ring veterinarian was needed. Because the pursual of diagnostic testing and return doctor follow-up is at the discretion of the owner, local recurrence or me -tastasis could have gone undetected in some dogs. We attempted to lessen the impact of this limitation by separating local recurrence and metastasis cases into confirmed and suspected cases. Additionally, because of the study’s retrospective nature, intraop -erative and postoperative complications could not be attributed to the anal sacculectomy procedure alone, potentially falsely increasing complication rates due to anesthetic or other concurrent surgical procedure complications.In conclusion, the traditional and modified closed anal sacculectomy techniques resulted in moderate rates of recurrence of AGASACA. No long-term ben -efits were identified when performing the modified closed approach as opposed to the traditional closed anal sacculectomy technique. The results support sur -geon preference in choosing a technique for anal sacc -ulectomy for neoplastic disease. A clinical evaluation is warranted to assess whether the modified technique decreases contamination of surrounding tissue and the potential of postoperative infection when the pro -cedure is performed for other anal sac diseases, such as chronic anal sacculitis, recurrent impaction, and anal sac abscess.AcknowledgmentsNone reported.DisclosuresPresented in part at the Veterinary Cancer Society and Veterinary Society of Surgical Oncology 2023 Collaborative Conference, April 20, 2023.No AI-assisted technologies were used in the generation of this manuscriptFundingThe authors have nothing to disclose.

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