Ch 118 USMI

Question 1

List the interacting mechanisms which are responsible for maintaining continence

physiologic control

Answer 1

Bitches have no true bladder neck sphincter, so continence is maintained by many interacting factors
* Urethral smooth muscle tone (most prevalent in the cranial 1/2 of the urethra)
* Striated muscle tone (caudal third of the urethra)
* Natural elasticity of the urethral wall
* Physical properties of the urethra (length and diamtere, pelvic diaphragm, engorgement of suburothelial venous plexus)
- bladder filling enhances urethral smooth muscle tone
- - Urethral closure further supported by reflex contraction of the external striated sphincter and pelvic diaphragm muscles

Question 2

The neuromuscular function

Answer 2

• storage phase
  sympathetic stimulation (hypogastric nerve) of alpha-1 receptors induces smooth muscle contraction at the bladder neck and proximal urethra
  sympathetic stimulation to beta receptors in the bladder results in detrusor muscle relaxation to allow bladder filling
  somatic (pudendal nerve) stimulates nicotinic cholinergic receptors in the external urethral sphincter, resulting in striated muscle contraction.
• bladder volume full
  parasympathetic stimulation (pelvic nerve) stimulates detrusor muscle contraction and inhibits sympathetic tone to the urethra.
• release of urine once voluntary urethral relaxation occurs.
• Urinary incontinence = intravesicular pressure involuntarily exceeds that exerted by the urethral sphincters

Question 3

UI in female dogs

Question 4

List potential causes of congenital USMI

Answer 4

Abnormally short or absent urethra (esp. cats)
Diverticula and dilatations in juvenile male dogs

Question 5

PATHOPHYSIOLOGY

Proposed mechanisms: 3

Answer 5

• The exact pathophysiology of USMI is unknown > multifactorial

Proposed mechanisms:
- hormonal (decreased estrogen levels altering urethral tone, increased gonadotropin levels, decreased local cyclooxygenase-2 expression)
- structural (altered collagen and smooth muscle, shortened urethra, intrapelvic bladder)
- functional (urethral tone)

Question 6

Urethral Tone and Length

Answer 6

• Urine leakage usually occurs when intraabdominal pressure rises, such as during recumbency or barking.
• Based on results of urethral pressure profilometry, bitches with USMI have lower maximal urethral closing pressure and shorter functional profiles than control dogs (Holt 1988)
• female dogs with USMI tend to have shorter urethras than continent animals
• Tail docking has also been shown to have a positive association with USMI

Question 7

Bladder Neck Position

Answer 7

• Good evidence to support that an intrapelvic bladder neck contributes significantly to incontinence from USMI
• caudal bladder neck positioning is thought to result in changes in conveyance of abdominal pressure to the urethra
• Caudal bladder position is also associated with a shorter total urethral length, which may be a contributing factor.
• (Holt 2000)
• pronounced shifting of the bladder caudally when they move from a standing to recumbent position, suggesting a deficiency of the supporting mechanisms in their lower urinary tract> status does not play a role in this mechanism.

Question 8

Body Size and Breed

Answer 8

• large and giant-breed dogs are seven times more likely to develop urinary incontinence
• Certain breeds may be at more risk (Pinschers, Sheepdogs, Weimaraners)
• Obesity believed to worsen the degree of urinary incontinence

Question 9

Gonadectomy

Answer 9

• Prevalence 5-20% in neutered females
• The risk for developing urinary incontinence is eight times higher in spayed dogs than intact females
• conflicting evidence for USMI development and neutering in relation to the time of the first heat.
• OHE < 3 mo of age in one study had greater incontinence compared with dogs undergoing the procedure after the first heat cycle
• Several studies found no association with USMI and timing of OHE
• A systematic review of 1853 records included only 3 articles on this topic and concluded no consistent or strong enough evidence to make recommendations on the effect of OHE or age at the time of OHE for the development of USMI
  Beauvais 2012.
• The canine female urethra is composed of approximately 75% collagen, in total volume, including elastic fibers. females have a higher collagen-to-muscle ratio
• Neutering results in significantly higher proportions of collagen However > no effect on collagen types I, III, and IV or smooth muscle α-actin of the urethra
• Gonadectomy results in decreased vaginal and vestibular dimensions >no relation to urinary incontinence

Question 10

Hormonal Status

Answer 10

• Hormonal changes during the estrous cycle have documented effects on the function and morphometry of the lower urinary tract in dogs.

Oestrogen
- receptors are prominent in the urethra and increase the sensitivity of a-receptors to catecholamines, which improves urethral tone.
- Alterations in urethral tone are observed both with normal estrus and iatrogenically induced alterations in estrogen levels
- intact female dogs plasma estrogen levels are similar to those in sterilized female dogs
- not all incontinent dogs improve with estrogen supplementation. >Therefore, unlikely that estrogen alone is the sole factor for USMI

gonadotrophins
- Increase in gonadotrophins has been postulated to be a contributing factor to USMI due to lack of negative feedback on the pituitary gland.
- (GnRH) agonists has been shown to temporarily restore continence in bitches with USMI.
- The effect of gonadotrophins may be via their regulation of expression of cyclooxygenases in the synthesis of prostaglandins,
- Gonadectomized dogs have lower expression of COX-2 > a definitive link to urinary incontinence has yet to be identified.

Question 11

Genital Conformation

Answer 11

• Vestibulovaginal stenosis (stricture or persistent perforate hymen) linked to urinary incontinence in that urine is thought to accumulate cranial to the stenosis during micturition
• no difference in the prevalence in continent and incontinent
• It may worsen signs of USMI and lead to vaginitis from urine pooling.
• Affected dogs should also be evaluated for recessed vulva > presents similar to USMI.
• Treatment of concurrent recessed vulva may or may not improve USMI (conflicting reports)

Question 12

Urethral Sphincter Mechanism Incompetence in Male Dogs

Answer 12

• Although rare, USMI in male congenital or acquired condition
• Prostatic or pelvic urethral abnormalities (urethral dilatation or prostatic diverticula) are the most common congenital causes.
• The acquired form is associated with neutering
• affected males dogs often have an intrapelvic bladder neck, supporting the importance of intraabdominal pressure in development of the condition

Question 13

What breeds are overrepresented with USMI?
How much more likely is USMI to occur in large/giant breeds?

Answer 13

Old English Sheepdog
Doberman
Rottweiler
Weimeraner
Irish Setters
Large- and giant-breed dogs are 7x more likely to develop USMI

Question 14

How is USMI diagnosed?

Answer 14

Mostly a diagnosis of exclusion. Need to rule out other causes of incontinence such as ectopic ureters or conformational abnormalities causing overflow (recessed vulva)

Question 15

Diagnostic Assessment

Answer 15

• animals with USMI are predominantly incontinent when recumbent.
• • Vulvar conformation should be assessed
• Baseline diagnostics > CBC, chemistry panel, urinalysis, urine culture, digital rectal examination, and vestibular examination
• Medical management of USMI may be attempted empirically before advanced diagnostics
• Advanced imaging, CT excretory urography or cystoscopy, should be considered in patients who have been incontinent since birth or are suspected of having other complicating conditions

Question 16

Urodynamics

Answer 16

• objective diagnostic tool available to diagnose USMI, but lack of availability and concern regarding the reliability of the results has limited its widespread use
• air technology compare favourably to water-based systems
• cystometrography and urethral pressure profiles enables both the bladder and urethral components > may identify patients likely to be refractory to standard treatments
• Diagnosis was then confirmed in all dogs by observation of a flat curve and a low maximal urethral closure pressure (MUCP) on the urethral pressure profiles (UPP).
• Urethral pressure profiles measuring pressure along the length of the urethra are required to document decreased urethral tone.36 There is wide interindividual variation, and the test is affected by sedation, movement, and muscle activity.
• Incontinent bitches had a higher mean percentage of negative peaks extending below the resting intravesical pressure than continent bitches

Question 17

ACVIM consensus UPP

Answer 17

Urodynamic studies are not considered necessary in dogs that initially present for voiding or storage disorders
but might provide further information regarding the cause of UI in refractory cases

All anesthetic agents will alter (usually decrease) the
maximum urethral closure pressure (MUCP) and the capability for the
dog to have a normal detrusor reflex during a CMG

Question 18

urethral sphincter pressure profile

Answer 18

level of the trigone. The catheter is slowly withdrawn at a standard rate (0.5-1mm/s) while warm sterile water is infused at 2ml/min
This generates a pressure curve that is visualized on the computer screen.
From this curve the following are recorded:
1. Maximal Urethral Pressure (MUP): the maximal pressure generated in the
urethra
2. Maximal Urethral Closure Pressure (MUCP): the difference between the
MUP and the perfused intravesicular pressure
3. Functional Profile Length (FPL): the portion of the UPP tracing during
which urethral pressure exceeds intravesical pressure
4. Functional Area (FA): the area under the FPL curve

normal urethral pressure;
146.5 ± 41.9 cm H2O (Fischer et al. 2003). According to this data, the minimum urethral pressure in normal, conscious, continent
dogs was 104.6 cm H2O

There is wide interindividual variation, and the test is affected by sedation, movement, and muscle activity

The LPP is thought to be the most accurate method
of predicting clinical response to colposuspension for the
treatment of urinary incontinence in female dogs > The minimum intravesical pressure necessary to
cause external leakage is recorded as the LPP.

Question 19

urinary incontinence is divided into two main categories: disorders of storage and disorders of voiding

Answer 19

disorders of urine storage:
- Functional causes = (USMI), sacral spinal cord injury affecting the pudendal or pelvic nerves, dysautonomia and detrusor instability
- Mechanical causes = ectopic ureters (EU), a short urethra (congenital/anatomical)

Disorders of urine voiding
- larger postvoiding residual volume +/- secondary overflow urinary incontinence
- Functional Disorders = Failure of the bladder to contract adequately (atonic bladder), Failure of the urethra to relax appropriately, Idiopathic functional outflow obstruction
- Mechanical Disorders = luminal, intramural, or extramural obstruction (neoplasia, phimosis, stricture, lith, trauma)

neurogenic disorders of voiding

Question 20

The Cystometrogram (CMG)
Indications for a CMG
Detrusor hyperreflexia

Answer 20

Pressures are measured as the bladder is being filled with
water indicating the degree of compliance of the bladder. The following values
are generally reported for a CMG:
1. Resting bladder pressure
2. Threshold pressure: the pressure at which the detrusor reflex occurs
3. Threshold volume: the volume at which the detrusor reflex occurs
4. Bladder compliance: calculated as the fluid infused (mL)/[bladder
pressure (cm H 0)–resting bladder pressure (cm H 0)]

Question 21

FOO

Answer 21

The recommended initial treatment in dogs with FOO is administration of an alpha-antagonist with or without a skeletal muscle relaxant

Dyssynergic
voiding patterns might be observed in which a relatively normal urine stream is initiated that rapidly becomes attenuated or tapered to
intermittent spurts and is accompanied by increased PVRV

Question 22

Treatment

Answer 22

• Most therapies for treatment of USMI will improve or even abate incontinence for some time.
• important for owners to understand, however, that it is unlikely that any one therapy alone will result in a permanent cure in many dogs.
• Current treatments available for the management of this condition include medical management, surgical options and minimally invasive procedures.

Question 23

List the main options for medical management.
What is the rate of single-therapy resulting in cure of incontinence?

Answer 23

• Phenylpropanolamine - alpha adrenergic agonist
• Oestrogens - Improve smooth muscle contractility and sensitivity to alpha-adrenergic stimulation
• GnRH analogues - decrease pituitary release of LH and FSH. Action suspected to be mainly on bladder function

50% of dogs will be cures with single therapy treatment

Question 24

Medical Management

Answer 24

• Theoretically, sympathomimetic or parasympatholytic agents should improve continence by increasing urethral tone or reducing intravesical pressure
• 10 to 20% of dogs are poorly responsive or become refractory to drug treatment and these dogs remain challenging to treat
  In approximately 50% of juvenile, intact female dogs, urinary incontinence will resolve after the first estrus
• If the owners do not want to delay treatment, phenylpropanolamine can be instituted until estrus occurs.
• Estrogens are contraindicated

Question 25

Phenylpropanolamine (PPA)

Answer 25

- α-adrenergic agonist acts on the smooth muscle of the urethral sphincter to increase tone = mainstay of medical treatment. - highly effective with 85∙7% dogs becoming continent after 28 days of treatment in a prospective, placebo controlled study (though admistered TID) Scott 2002 - side effects uncommon > hyperactivity, restlessness, hypertension and reflex bradycardia - Potential for the incontinence to become refractory to treatment when the medication is given long-term > Some hypothesise may be due to desensitisation or downregulation of receptors - clinical study, 1∙5 mg/kg PPA orally once daily was effective in producing long-term (up to 36months) continence in 8/9 dogs 89% efficacy (Claeys 2011) male dogs - PPA is still the drug of choice but is much less effective - positive effect only seven of 16 male dogs treated in one study

Question 26

Oestriol

Answer 26

- spayed female dogs may respond to treatment with estrogens such as estriol - may improve smooth muscle contractility and sensitivity to α-adrenergic stimulation - Used alone, efficacy to produce complete continence is reported to be 60%, 25% demonstrating a partial response - combined therapy with α-adrenergics and estrogens may reduce the total dose of each drug, as well as decreasing potential side effects (no current clinical trials) - Response to therapy will eventually wane in some dogs > may be a result of desensitization of estrogen receptors

Question 27

Androgen

Answer 27

- used in castrated male dogs but appears to be less effective with side effects including PH and aggression - recent study of methyltestosterone on spayed female dogs reported 9/10 excellent results

Question 28

Gonadotropin-releasing hormone (GnRH)

Answer 28

- LH and FSH have been linked to incontinence - GnRH analogues decrease pituitary release of LH and FSH over time - GnRH analogues have been investigated for treatment of USMI in dogs and have shown efficacy in 71% cases (Reichler 2006) - well-tolerated and are available in long-acting forms, which are favourable characteristics but the lesser efficacy compared to PPA results in infrequent clinical use - Long-term data on use of GnRH analogues is lacking.

Question 29

When are oestrogens contraindicated in the treatment of USMI?

Answer 29

Prior to the first oestrus - Approx 50% of dogs will have their incontinence resolve after the first oestrus - Contraindicated due to potential adverse feedback on the pituitary

Question 30

Surgical Management

Answer 30

- pursued after a dog has failed to respond or refractory to medical Surgical options for USMI: 1. **increase urethral resistance** (Bulking agents Transpelvic urethral sling Transobturator vaginal tape Artificial urethral sphincter) 2. **increase urethral length or relocate bladder neck** position (Colposuspension Urethropexy Cystourethropexy)

Question 31

List the main surgical options for USMI

Answer 31

Colposuspension Urethropexy Cystourethropexy Bulking agents (submucosal bovine cross-linked collagen) Transpelvic urethral sling Transobturator vaginal tape Artificial urethral sphincter

Question 32

What vessels need to be identified and avoided during colposuspenstion?

Answer 32

External pudendal vessels

Question 33

What is the prognosis after colposuspension?

Answer 33

53-55% complete continence Recurrence in approx 11%

Question 34

Colposuspension

Answer 34

- goal = **increase urethral length** by relocating the bladder neck to an intraabdominal position. - originally described in women by Birtch, adapted by Holt for the bitch. - Essentially the vagina on either side of the urethra is anchored with sutures to the prepubic tendon > increase in functional urethral length. - repositioning increases leak-point pressure by reestablishment of the normal intraabdominal pressures across the proximal urethra and bladder neck. - SURGERY: catheter is placed so the balloon rests within the trigone, facilitating identification of the urethra and bladder neck. A caudal midline celiotomy is performed, Each side of the vagina is then sutured to the prepubic tendon, approximately 1.0 to 1.5 cm away from midline using large-gauge, monofilament, nonabsorbable suture material Urethra is examined to make sure it is not being compressed to reduce post-op dysuria - differences when individual surgeons recreate the technique: suture position, number of sutures and degree of cranial traction may influence outcome.

Question 35

Outcome

Answer 35

- largest retrospective study in 150 bitches, reported that 53% dogs were cured by the procedure, 37% were significantly improved and 10% showed no response. Relapse possible in 11% (Holt 1990) - subsequent study concurred minimal complication rate but failed to replicate Holt’s results, with only three of 22 dogs (13%) remaining continent at 1 year postoperatively without the addition of medical management Rawlings 2001

Question 36

Complications

Answer 36

- 11% to 15% - Dysuria, increased frequency of urination, recurrent urinary tract infections, slight tenesmus, and defecation

Question 37

Urethropexy, Cystourethropexy

Answer 37

- **relocate the bladder neck** into a more cranial, intraabdominal position. - increase urethral resistance due to demonstrable kink in the urethra at the level of the urethropexy on postoperative vaginourethrogram - uses urethral rather than vaginal sutures to relocate the bladder neck (though associated with higher complications rate) - only study evaluating urethropexy as the sole procedure > 56% of bitches were cured, 17% failed or relapsed - Cystopexy alone is contraindicated as a treatment for USMI, because it may result in detrusor instability (believed to be a cause of functional urinary incontinence due to an overactive bladder ) **complications > 21%**, - relapse, increased frequency of urination, dysuria, and anuria recent retrospective study - combined urethropexy and colposuspension, 70% were completely continent at a median follow-up time of 39.5 months complication rate was 10% Martinoli 2014

Question 38

Bulking Agents

Answer 38

Increasing Urethral Resistance - Submucosal urethral injections are less invasive - endoscopic (urethrocystoscopic) injection of collagen in the proximal urethra immediately below the mucosa 1.5 to 2 cm caudal to the vesicourethral junction circumferentially - Originally Teflon ( granuloma formation) - Bovine cross-linked collagen >** clinical efficacy of 53%** after the initial injections Sumner 2012 **Advantages** - minimally invasive, continence rate similar to surgery, lack of aftercare and minimal complications **Disadvantage** - short duration of action (1-24months), require multiple procedures or the addition of medical therapy to maintain continence - Should be reserved for clients wishing to avoid a surgical solution, or for older bitches

Question 39

Autologous skeletal muscle progenitor cells

Answer 39

- urethral submucosal injection of skMPC, with or without adjuvant medication lead to improved continence in dogs that have failed medical management. - 14 of 15 dogs - 93% - achieved a continence score of 4 (mostly continent) or 5 (always continent) 3-12mo after injection - success rate that is equal or higher than other advanced treatments Vaden 2022

Question 40

Transpelvic Urethral Sling Transobturator Vaginal Tape

Answer 40

Transpelvic Urethral Sling - Two dogs developed fistulas 2 and 3 years after surgery from the polyester ribbon Transobturator Vaginal Tape - popular in women, minimally invasive and high success - goal of **supporting the midurethra** and having it remain closed during increased abdominal pressure - Clinically, complete continence was reported in 92% to 100% of female dogs in the short-term period with reasonable long-term results as well - Complications > dysuria in 33% and fistula Deschamps 2015 transobturator vaginal tape insideout technique - TVT-O alone was successful in long-term continence in 40% Hamon 2019

Question 41

What location is recommended for injection of bovine cross-linked collagen?

Answer 41

* Immediately below the mucosa, 1.5-2cm caudal to the vesicourethral junction * Repeated circumferentially until injection sites appose one another - most dogs need three injections

Question 42

What is the prognosis with a transpelvic urethral sling?

Answer 42

* complete continent in 92-100% in short term * Long term: 3/12 completely continent, 3/12 improved, 3/12 incontinent episodes 1+ times a month

Question 43

Where is the recommended location of an artificial urethral sphincter in female and male dogs?

Answer 43

Female: At least 2cm caudal to bladder neck to avoid impedence of the ureters Male: 1cm caudal to prostate

Question 44

How do you measure for sizing of a artifical urethral sphincter?

Answer 44

* Meaure the circumference of the urethra in surgery with suture or a penrose drain. * Appropriate sphincter size estimated to be 50% of the circumference * Most commonly used sized are 8,10,12mm (6-16mm available) with a cuff width of 14mm (available in 11 or 14mm)

Question 45

What % or dogs are expected to be continent without inflation of the artifical sphincter? What are the general rules of cuff inflation?

Answer 45

* 33-45% continent with uninflated cuff * Must wait 6 weeks prior to inflation to allow resolution of inflammation and revascularisation of dissected urethra * Inj 0.05-0.2ml sterile saline at weekly or monthly intervals

Question 46

Artificial Urethral Sphincter - Sx

Answer 46

- 2-cm section of urethra: 2 cm caudal to the bladder neck avoid ureters, in male > 1 cm caudal to the prostate - size based on luminal diameter of the closed cuff - urethral circumference is measured by using a strand of suture - slightly oversized to avoid obstruction of the urethra > estimated as being roughly 50% of the circumference - oriented so that the actuating tubing is directed cranially, 2-0 polypropylene to secure the cuff closed. - Subcutaneous port placed. - The cuff is temporarily inflated by saline injection > volume required to produce total urethral occlusion is measured and recorded for future reference - kept in hospital until they are observed to urinate without straining.

Question 47

AUS - Outcome

Answer 47

- Many completely continent with placement of the artificial urethral sphincter alone (33% to 45%) - remaining dogs require one or more saline infusions into the artificial urethral sphincter + continued medical management to maintain continence. - reported continence rates of 36∙4 to 90% - wide variation dt follow-up times, classification of “continence”, underlying aetiology (USMI versus EU), surgical technique, post-op (inflation protocols) and client expectations - In some, not possible to achieve a balance between continence and obstruction = limitation of the device Reeves 2013 - Retrospective of 20 dogs - Complete continence achieved in 90% in long term (min 1 yr) Gomes 2018:

Question 48

AUS - complications

Answer 48

- common in all studies, most are minor (seroma, UTI, slow urination). - Major requiring device removal in **5 to 16∙6%** (infection or urethral compression/stricture)

Question 49

Treatment in Male Dogs

Answer 49

- USMI in male dogs is less responsive to medical management than USMI in bitches. - Surgery appears less successful in males compared with females, although the reviewable population is smaller. - Relocation of an intrapelvic bladder neck via deferentopexy or prostatopexy to the prepubic tendon.49 - AUS placed on 19 male dogs - 8/15 remained completely continent in longterm > 53% Complications > 56%, major 31% Bohlen 2022:

Question 50

OUTCOME/Prognosis

Answer 50

- Comparison of options challenging due to varying preop factors, lack of objective outcome measures and variability in the definition of a success - medical treatment is successful in a high number of bitches = treatment of choice initially Following critical evaluation of the literature for the surgical options: - long-term outcome continues to be relatively poor - no strong evidence to enable recommendation of one technique over the others. - AUS > may offer a long-term advantage Gomes 2018 - new treatments for USMI in dogs is driven by the absence of a single successful treatment for this condition. Future developments: - should be lead by an improved understanding of the pathophysiology > Treatments to date have been adapted from human medicine >cell therapy to restore functional muscle within the urethra > improved by combining current treatments for USMI

Question 51

Kendall 2024 – ACVIM consensus on dx and management of urinary incontinence - surgery for medically unresponsive USMI with normal cystoscopy and -ve culture - surgery: urethral bulking to be considered for older dogs with acquired incontinence - initial success with x-linked collagen 80% → many recurrence within 1y artificial urethral sphincter for concurrent anatomicala anomalies, young dogs or ectopic ureters with ongoing incontinence - 82-92% improved continence over 2-3y - device removal required in 0-17%

Question 52

Artificial urethral sphincter in male dogs with urethral sphincter mechanism incompetence: 19 cases (2010–2017) M. Bohlen 2022

Answer 52

failed medical management 18/19, unknown in 1/19 - continence: short-term improvement 16/19 (84%); full continence 13/19 (68%) post-op long-term improvement 9/15 (60%); full continence 8/15 (53%) - 15/19 required at least one inflation (long-term ≥12 months) 8 cases complete continience for ~2000d - complications: overall 9/16 (56%) - minor: 4/16 (25%) - hematoma, stranguria/temporary dyssynergia, port inflam - major: 5/16 (31%) - stranguria/mechanical obstruction, persistent dyssynergia, port fistula, port rotation A high-complication rate is associated with this procedure.

Question 53

Treatment of urinary incontinence in a cat with genitourinary dysplasia using an urethral sphincter occluder A. Fournet 2021

Answer 53

urinary incontinence in a cat with genitourinary dysplasia using AUS Urethral pressure profilometry suggested urethral sphincter Inflation of the occluder under urethral pressure profilometry was subsequently performed and resolved the incontinence The maximal urethral pressure recorded was 2 cm H2O (RI: 25–35) (Joubert 2002), suggestive of USMI.

Question 54

The effect of neutering on the risk of urinary incontinence in bitches – a systematic review W. Beauvais 2012

Answer 54

The effect of neutering on UI: systematic review 3 studies >moderate risk of bias > weak evidence that neutering, particularly before the age of three months, increases the risk of urinary incontinence. However, overall the evidence is not consistent nor strong enough to make firm recommendations on the effect of neutering or age at neutering on the risk of urinary incontinence.

Question 55

Spaying and urinary incontinence in bitches under UK primary veterinary care: a case–control study C. Pegram 2019

Answer 55

427 incident cases and 1708 controls Prior spaying was associated with increased odds of urinary incontinence (odds ratio: 3.01; 95% CIs: 2.23 to 4.05). Increased odds of urinary incontinence were additionally associated with increasing age and increasing bodyweight. Age at spay was not associated with urinary incontinence. OR = 3 means the odds triple, but the probability does not necessarily triple. The effect on probability depends on the baseline risk in the control group.

Question 56

Canine urethral sphincter pressure profile under incremental inflation of an artificial cuff: a cadaver study E. J. Milodowski 2019

Answer 56

Canine urethral sphincter pressure profile under incremental inflation of an artificial cuff: a cadaver study profilometry in five cadavers following AUS placement - associated with an increase in urethral pressure, correlated with inflation volume. - The correlation was non-linear and demonstrated considerable individual variation. Rapid increases in urethral pressure over a small range of filling volumes (0.15 mL increments) > why some become suddenly dysuric > suggest smaller increments of filling (0.05 to 0.1 mL)

Question 57

Long-term outcome of the transobturator vaginal tape inside out for the treatment of urethral sphincter mechanism incompetence in female dogs Martin Hamon 2019

Answer 57

- outcome: 1y post-op: 7/12 (58%) complete continence long-term f/u (median 85m): 4/10 (40%) complete continence without medical tx Additional postoperative medical treatment was effective in restoring continence in another 40% of the dogs. - recurrence in 6/10 at median 2m (1-20) post-op → 4/6 continent, 2/6 improved with medical treatment - no post-op complications

Question 58

Gomes 2018 – AUS for USMI in 20 dogs - median continence improved post-op at all time points - complete continence without medication 80%; 10% additional with medication - complications: minor 13/20 (65%) - dysuria, bacterial cystitis, longer urination time, seroma, urinary retention, hematuria, pain on urination major 1/20 (5%) - AUS removal after 28m (persistent stranguria)