Orthognathic/Cleft/OSA Flashcards
When performing a floor-of-the-mouth lowering procedure, it is necessary to:
A. perform a subperiosteal dissection
B. cover the denuded region with a soft tissue graft
C. avoid altering muscle attachments in patients diagnosed with retrolingual sleep apnea
D. detach all muscle attachments at the genial tubercle
Answer: C
Rationale:
Patients with suspected or diagnosed obstructive sleep apnea should not have muscle attachments altered in floor-of -mouth lowering procedures because this may worsen or create obstruction. Supraperiosteal dissections are performed and the incision margin is sutured to the periosteum at the depth of the vestibule. It is not necessary to place a soft tissue graft over
the denuded periosteum as this may be allowed to secondarily epithelialize. The genioglossus muscle attachments at the genial tubercle may be partially removed to increase the lingual sulcus, but approximately ½ oproper tongue function.
Reference:
Fonseca RJ Oral and Maxillofacial Surgery Vol. 7 p. 49WB Saunders2000
While under general anesthesia for a maxillo-mandibular advancement procedure, an obstructive sleep apnea patient is exhibiting significant hypotension. Pre-operatively, the patient’s baseline blood pressure was 170/90. On pre-operative physical examination, the patient had jugular venous distention and a para-sternal PMI. In this circumstance what is the most appropriate management for hypotension? A. Intravenous fluid bolus B. Trendelenberg positioning C. Intravenousalpha-1blockade D. Intravenous vasopressor agent
Answer: D
Rationale:
This OSA patient has physical signs of pulmonary hypertension. The most appropriate manner to treat anesthetic induced hypotension without exacerbating right heart failure is an IV vasopressor agent (e.g. phenylephrine). Fluid bolus may exacerbate right heart failure and positioning has little effect on anesthesia induced hypotension. Alpha blockade may prevent the physiologic responses during efforts to correct the hypotension.
Reference:
Ronderos, J and Boyd, G: Anesthetic Considerations for Obstructive Sleep Apnea. Oral and Maxillofacial Clinics of North America: Vol. 7, No. 2 1995,
Hess, ML and Sibbald, WS: Applied Cardiovascular Physiology in the Critically Ill. Textbook of Critical Care, 4th Edition 2000, Chapter 89: 1001
In a patient who undergoes mandibular advancement, the ratio of soft tissue changes to hard tissue changes at pogonion would most likely be which of the following? A. 1:1 B. 1:2 C. 2:3 D. 1:4
Answer: A
Rationale:
During mandibular orthognathic surgery, the overlying soft tissues follow osseous changes closely. Generally, the soft tissues follow bony movements in a 1:1 ratio. The exception is the lower lip which relies heavily on the position of the incisor teeth and can also be affected by the position of the upper lip.
Reference:
Betts NJ, Dowd KF. Soft tissue changes associated with orthognathic surgery. Atlas Oral Maxillofac Surg Clin North Am 8: 13-38, 2000.
In a distraction osteogenesis procedure, the consolidation phase of treatment extends until which of the following stages of bone healing? A. Hematoma formation and inflammation B. Soft callus formation C. Hard callus formation D. Bony maturation
Answer: C
Rationale:
Bony healing after a fracture or osteotomy consists of four histologically distinct stages: an inflammatory phase, soft callus formation, hard callus formation, and bony maturation/remodeling. During soft callus formation, fibrovascular structures bridge the osteotomized bone segments and there is recruitment of fibroblasts and mesenchymal stem cells within the fracture zone. It is this flexible soft callus which is lengthened via gradual traction during the subsequent distraction phase. Once the desired bony lengthening has been achieved, the distraction appliance is left in place and serves as a stabilizing device while the regenerate bone (soft callus) matures and calcifies forming a hard callus. Most distraction protocols recommend a consolidation/healing phase of at least 6 to 8 weeks.
Reference:
Crago C.A., Proffit W.R., and Ruiz R.L. Maxillofacial Distraction Osteogenesis. Pp. 357- 393. In: Proffit W.R., White R.P., and Sarver D.M. (Eds) Contemporary Treatment of Dentofacial Deformity. Philadelphia. Mosby. 2003.
A patient with an underlying diagnosis of Hemifacial Microsomia presents with severe unilateral hypoplasia of the ascending ramus, condyle, and glenoid fossa. There is little to no translational movement of the affected condyle. This mandibular-TMJ deformity is consistent with which skeletal type hemifacial microsomia? A. Type I B. Type IIa C. Type IIb D. Type III
Answer: C
Rationale:
Patients with Hemifacial Microsomia (oculoauriculovertebral spectrum) will present with varying degrees of mandibular and temporomandibular joint hypoplasia as a primary finding in the condition. Kaban has refined a classification system useful in defining the degree of mandibular deformity in these patients. The specific type of mandibular/TMJ deformity present is a critical factor in deciding upon the specific reconstructive techniques that will be employed. The following is a brief synopsis of each Kaban type:
Type I: All skeletal components (glenoid fossa, condyle, ascending ramus) are present with a mild degree of hypoplasia. Normal function is present.
Type IIa: All of the skeletal components demonstrate a moderate degree of hypoplasia. While present, the condyle may appear to be malpositioned so that it is anterior and medial to the contralateral (normal) side. Function is affected, but remains satisfactory.
� Type IIb: There is moderate to severe hypoplasia of the glenoid fossa and the condyle- ramus complex. Despite an abnormal and severely hypoplastic condyle, many patients will still have a working joint and an actual “stop” where the condylar segment seats against the skull base. Most patients will demonstrate function that is limited to simple rotation of the condyle without any translational movements.
� Type III: This is the most severe form of mandibular hypoplasia with complete absence of the condyle-ramus complex and the glenoid fossa. The affected side of the mandible has no working articulation against the skull base.
Reference:
Kaban LB, Moses MH, Mulliken JB. Correction of hemifacial microsomia in the growing child: A follow-up study. Cleft Palate J 23 (Suppl 1) 50, 1986.
Kaban LB. Congenital Abnormalities of the Temporomandibular Joint. In: Kaban LB and Troulis MJ (Eds). Pediatric Oral and Maxillofacial Surgery. Pp. 302-339. Elsevier, Philadelphia, 2004.
During sagittal split osteotomy, the possibility of direct injury to the inferior alveolar neurovascular bundle can be minimized when the vertical component of the osteotomy is made over which of the following regions? A. Lateral to the first molar B. Lateral to the second molar C. Lateral to the third molar D. Lateral to the retromolar region
Answer: B
Rationale:
The position of the inferior alveolar neurovascular bundle is an important determinant in the design of the sagittal split osteotomy. The neurovascular bundle travels just under the facial cortical plate of the mandible. Whether the osteotomy is made with rotary instruments or a reciprocating saw, the vertical cut must be carried just through the cortical plate (i.e. monocortical). The thickness of the bone over the neurovascular bundle is greatest in the area of the second molar. The vertical osteotomy should be placed lateral to the second molar unless circumstances dictate otherwise.
In a distraction osteogenesis procedure, the latency phase of treatment corresponds to which of the following stages of bone healing? A. Hematoma formation and inflamation B. Soft callus formation C. Hard callus formation D. Bony maturation
Answer: B
Rationale:
Bony healing after a fracture or osteotomy consists of four histologically distinct stages: an inflammatory phase, soft callus formation, hard callus formation, and bony maturation/remodeling. During soft callus formation, fibrovascular structures bridge the osteotomized bone segments and there is recruitment of fibroblasts and mesenchymal stem cells within the fracture zone. It is this flexible soft callus which is lengthened via gradual traction during the subsequent distraction phase.
An 8-month-old female infant undergoes early mandibular advancement with distraction osteogenesis in order to alleviate airway obstruction related to severe mandibular hypoplasia. Bilateral mandibular osteotomies are completed and internal distractors are placed and confirmed. Surgery is followed by a 9 day latency phase. Upon activation of the right distractor, heavy resistance is encountered and the bone segments appear immobile. Which of the following is the most likely cause of this complication?
A. Excessive soft tissue resistance
B. Incomplete osteotomy at the time of surgery
C. Malfunction of the distractor
D. Early consolidation of the osteotomy
Answer: D
Rationale:
In most patients, a latency phase of 5 to 7 days allows for adequate formation of a soft callus before active distraction is initiated. If activation of the distractors is initiated too early, decreased bone formation results. If the latency period is too long, conversion to a hard callus begins and early healing of the osteotomy will prevent mandibular lengthening. In young children, bone healing occurs much faster and little or no latency phase is required.
The “Holdaway Ratio” is most useful in planning which of the following procedures? A. Maxillary osteotomy B. Mandibular osteotomy C. Bimaxillary osteotomies D. Genioplasty
Answer: D
Rationale:
The Steiner analysis is a cephalometric approach utilized to directly evaluate the protrusion of the upper and lower incisors. The position of the maxillary and mandibular incisors is related to Nasion-A point (N-A) and Nasion-B point (N-B) lines using both angular and linear measurements. Within this analysis, the “Holdaway Ratio” is used to evaluate the prominence of the mandibular incisors and bony chin. The ratio is calculated by comparing the distance of the lower incisor edge and pogonion to the N-B line. Ideally, the Holdaway Ratio should be approximately 1.0 in males and 0.5 to 1.0 in females. This relationship is useful in planning for genioplasty.
A 17 year old female patient presents for correction of her Class III dentoskeletal deformity consistent with a diagnosis of mandibular hyperplasia. A 4 mm of reverse overjet is noted. A submentovertex radiograph obtained during the initial evaluation reveals a “V” shaped mandible with divergent rami. Which surgical procedure for mandibular setback would result in the greatest alteration in intercondylar width in this patient?
A. Bilateral sagittal split osteotomies with lag screw fixation
B. Transoral vertical ramus osteotomies with lag screw fixation
C. Bilateral Inverted “L” osteotomies with miniplate fixation
D. Bilateral “C” osteotomies with miniplate fixation
Answer: A
Rationale:
One of the technical considerations that must be considered when choosing a specific procedure for mandibular setback surgery is the actual shape of the mandibular arch form and rami. In patients with a “U” shaped mandible, either bilateral sagittal split osteotomies (BSSO) or a transoral vertical ramus osteotomy may be utilized for mandibular setback in Class III patients. When the mandible is “V” shaped with flared rami, then the procedure that results in the least condylar width change is the transoral vertical ramus osteotomy. If a patient with a “V” shaped mandible undergoes BSSO, a gap is created posteriorly between the cortical plates of the proximal and distal segments. If lag screws are used for rigid fixation, the gap is closed and there is narrowing of the intercondylar width.
Which of the following is a special consideration when performing sagittal split osteotomy for mandibular advancement in children?
A. The lingula and inferior alveolar foramina are located in a more superior and posterior position in the ramus of children than in adults.
B. The sagittal bone cuts should be positioned as far medially as possible.
C. The propensity for “greenstick” fracture of the inferior border of the mandible is lower in children
than in adults.
D. Simultaneous removal of partially developed third molar teeth is not possible in children.
Answer: A
Rationale:
The lingula and inferior alveolar foramina are located in a more superior and posterior position in this age group. This has technical implications in determining the vertical placement of the medial osteotomy of the ramus. If the medial bone cut is positioned high on the ramus, then injury to the nerve is avoided , but the risk of unfavorable split (i.e. buccal plate fracture) increases. In children, the sagittal component of the osteotomy design should be placed as far laterally as possible in order to avoid injury to the developing teeth. Children will have a higher propensity for “greenstick” fracture along the inferior border of the mandible. Their bone is more cancellous in nature and this often results in a longer area of fracture along the inferior border of the mandible. Developing third molars can be removed after the mandibular ramus has been split. In cases where the third molar teeth are only partially developed, they can still be enucleated while the proximal and distal segments are separated
Which of the following is a contraindication for the use of a total mandibular subapical osteotomy?
A. Condylar hypoplasia
B. Relapse after sagittal split osteotomy
C. Skeletal apertognathia
D. Mandibular vertical alveolar deficiency
Answer: C
Rationale:
Skeletal anterior open bite (i.e. apertognathia) is the result of a maxillary growth problem and is frequently associated with a concomitant transverse maxillary discrepancy. The use of a total mandibular subapical osteotomy for correction of an anterior open bite requires counterclockwise movement of the dentoalveolar segment, does not address the maxillary deformity, and is associated with a high rate of skeletal relapse. Appropriate management of apertognathia requires correction of the maxillary problem usually consisting of segmental Le Fort I level surgery.
The use of the total mandibular subapical osteotomy is limited to correction of malocclusions that can be addressed by repositioning the mandibular alveolar process only. The subapical osteotomy does not change the anatomical position of the mandibular body or symphysis. As a result, application of the total mandibular subapical osteotomy is limited to situations where there is retrusion of the dentoalveolar process with an otherwise normal facial morphology.
A 16-year-old female patient undergoes a Le Fort I osteotomy for maxillary impaction. Two days after surgery, guiding elastics are removed and assessment of the patient’s occlusion reveals an anterior open bite. What is the most likely cause of this complication?
A. Severe condylar resorption associated with fixation
B. Failure of maxillary hardware
C. Incomplete seating of the condyles during surgery
D. Incomplete downfracture of the maxilla during surgery
Answer: C
Rationale:
Le Fort I level osteotomy may be complicated by intraoperative malpositioning of the maxillomandibular complex after the jaws have been wired together. Pressure applied to the chin may bring the maxillary osteotomy together while unintentionally displacing the mandibular condyles. This is often caused when bony interferences along the posterior maxilla exist.
A 23-year-old female undergoes maxillary superior positioning with a midline splitting of the maxilla to widen the transverse dimension 9 mm. Following an uneventful early post-operative course, she returns one year later with an anterior open bite. Which of the following would most likely explain the open bite?
A. Poor positioning of the mandibular condyles intra-operatively
B. Relapse of the transverse widening of the maxilla
C. Idiopathic condylar resorption
D. Failure of the hardware placed in the anterior maxilla
Answer: B
Rationale:
Transverse expansion of the maxillary arch is often complicated by lack of long term stability. This is especially true when large movements are undertaken. As transverse relapse occurs, the lingual cusps of the maxillary posterior teeth move along the lingual inclines of the lingual mandibular cusps and the anterior open bite deformity is recreated.
A patient arrives at the emergency department 2 weeks following a LeFort I osteotomy with advancement and impaction of the maxilla by another surgeon. The parents describe and uneventful course to date until profuse epistaxis lead them to call 911. On your arrival, the patient is stable with the exception of borderline hypotension and the bleeding has stopped without intervention. Which of the following would be the most prudent next step?
A. Place bilateral anterior nasal packs for 24 hours.
B. Return to the operating room for exploration of the surgical site.
C. Fluid resuscitation and referral back to the operating surgeon.
D. Arrange interventional angiography.
Answer: D
Rationale:
Bleeding during Le Fort I osteotomy and downfracture is usually the result of injury to the terminal branches of the internal maxillary artery including the descending palatine and sphenopalatine arteries. Even after the Le Fort I downfracture, intraoperative injury to the descending palatine vessels may occur as a result of significant maxillary advancement or impaction. Postoperative hemorrhage following maxillary surgery typically presents as epistaxis with bleeding into the anterior and/or posterior nasal cavity. This may occur at any point during the first month after the surgical procedure and may be the result of breakdown of previous clot or necrosis of arterial vessels which were stretched by the surgical movement. An initial “sentinel” episode of brisk bleeding may stop spontaneously giving the false impression that the problem has resolved. Angiography and interventional radiology techniques provide detailed visualization and localization of the source of bleeding. The bleeding vessel may be stopped by embolization without the need to reopen the wound, remove rigid fixation devices, and dismantle skeletal segments. Angiography also allows detailed visualization of the arterial system and detection and management of pseudoaneurysm involving the internal maxillary artery or its terminal branches.
Which of the following is the most common source of venous bleeding during maxillary osteotomy at the LeFort I level?
A. Facial vein
B. Pterygoid venous plexus
C. Laceration of the pterygoid musculature
D. Descending palatine veins
Answer: B
Rationale:
The pterygoid plexus of veins is located directly posterior and medial to the maxilla. Its location makes it vulnerable to injury during creation of the osteotomy and use of an osteotome for pterygomaxillary disjunction. It is the most common source of intraoperative venous hemorrhage in patients undergoing LeFort I osteotomy. Management of venous hemorrhage from the pterygoid plexus requires packing and application of topical hemostatic agents.
Aside from serial cephalometric radiographs, which of the following is considered the next most reliable method of estimating the facial skeletal maturity?
A. Evaluation of the C-spine
B. Hand-wrist films
C. Panoramic evaluation of dental development
D. Tanner’s developmental stages
Answer: A
Rationale:
Radiographic assessment of the hand-wrist anatomy has been utilized to estimate a patient’s skeletal age when early orthodontic or surgical treatment is contemplated. The theoretical basis is that the chronology of ossification in the bones of the hand and wrist can be related to the rest of the skeleton. The relationship between the bony development of the hand-wrist complex and the facial skeleton is not well correlated. Recently, the radiographic assessment of the cervical spine vertebrae for estimating skeletal development has been proposes. Although not perfect, the use of cervical spine development as an indicator of skeletal age is better correlated with the facial skeleton and the adolescent growth spurt. This technique has the additional advantage that no additional radiographs are required since the cervical vertebrae are visible on a cephalometric radiograph.
The most unstable skeletal movement in orthognathic surgery procedures is: A. genioplasty – any direction. B. maxillary inferior repositioning. C. mandibular setback. D. segmental maxillary expansion.
Answer: D
Rationale:
Segmental surgery for transverse maxillary expansion is associated with the highest rate of relapse following orthognathic surgery. Palatal soft tissue resistance and dental compensations often add to this instability.
A 16-year-old patient with a skeletal Class III malocclusion is beginning orthodontic treatment in preparation for eventual LeFort I osteotomy and bilateral sagittal split osteotomies. The patient has significant crowding in both maxillary and mandibular arches and dental compensations are present. If extraction of maxillary and mandibular premolars is indicated, which of the following combinations is most appropriate given the patient’s clinical findings and eventual surgical plan?
A. Extraction of maxillary first and mandibular second premolars
B. Extraction of maxillary second and mandibular first premolars
C. Extraction of maxillary and mandibular first premolars
D. Extraction of maxillary and mandibular second premolars
Answer: A
Rationale:
Extraction of maxillary first premolars in this clinical situation allows for adequate space for alignment of crowded maxillary incisors. The space created allows for correction of inclination for teeth that have drifted forward during development of dental compensations. As the maxillary first premolar spaces are closed, the anterior teeth are retracted maximizing the degree of maxillary skeletal advancement.
In Class III patients undergoing presurgical orthodontic treatment, extraction of mandibular first premolars is rarely indicated. This is because closure of the extraction spaces will require retraction of the anterior teeth resulting in less favorable tooth-lip balance. Extraction of the second mandibular premolars provides the necessary space for alleviation of crowding while avoiding retraction of the incisors.
Which of the following statements regarding Passavant’s Ridge is correct?
A. It is observed only as part of the cleft palate malformation.
B. It does not facilitate velopharyngeal closure.
C. It forms along the palatopharyngeus muscle.
D. It forms along the superior constrictor muscle.
Answer: D
Rationale:
Passavant’s ridge is a soft tissue prominence which extends into the pharynx. The structure is usually described in association with cleft palate, but has been described in many normal subjects. The soft tissue structure also frequently contributes positively to velopharyngeal closure. The ridge usually forms along the superior border of the superior pharyngeal constrictor muscle, but its exact position on the posterior pharyngeal wall may vary.
When performing Le Fort I osteotomy in an ungrafted bilateral cleft lip and palate patient, which of the following surgical techniques should be avoided?
A. Autogenous bone grafting and rigid fixation
B. Osteotome separation of the pre-maxilla from the nasal septum and vomer
C. Advancement of lateral segments for closure of cleft-dental gap
D. Circumvestibular incision and maxillary downfracture
Answer: D
Rationale:
Preservation of an anterior buccal mucosal pedicle is critical to preserving blood circulation to the premaxilla in patients that have not undergone previous bone graft reconstruction of bilateral cleft defects. A circumvestibular incision in the ungrafted bilateral cleft lip and palate patient would lead to aspectic necrosis of the premaxillary segment. Maxillary advancement in these patients is carried out through separate right and left vestibular incisions with limited tunneling anteriorly. A small vertical incision within the midline may be utilized for separation of the nasal septum and mobilization of the premaxillary segment.
A child born with an isolated cleft palate presents with severe myopia early in life. The most likely diagnosis is which of the following syndromes? A. Pierre Robin Sequence B. Stickler Syndrome C. Van der Woude Syndrome D. Velocardiofacial Syndrome
Answer: B
Rationale:
Isolated cleft palate is associated with an underlying syndrome more frequently (as much as 50%) than cleft lip and palate. Stickler syndrome has been identified as the most common diagnosis causing both cleft palate and Robin sequence. Patients with Stickler syndrome demonstrate a collagen metabolism disorder. Relevant clinical findings include early myopia and an increased risk of retinal detachment which may go un-noticed early in life. It is recommended that infants with an isolated cleft of the secondary palate undergo formal ophthalmologic evaluation at some point during their first year of life.
van der Woude syndrome can be caused by deletions in chromosome band 1q32, and linkage analysis has confirmed this chromosomal locus as the disease gene site. van der Woude syndrome is an autosomal dominant syndrome typically consisting of a cleft lip or cleft palate and distinctive pits of the lower lips. The degree to which individuals carrying the gene are affected is widely variable, even within families. These variable manifestations include lip pits alone, absent teeth, or isolated cleft lip and palate of varying degrees of severity. Other associated anomalies have also been described. About 1-2% of patients with cleft lip or palate have van der Woude syndrome.
Velocardiofacial syndrome (VCFS) is a genetic condition characterized by structural or functional palatal abnormalities, cardiac defects, unique facial characteristics, hypernasal speech, hypotonia, developmental delay, and learning disabilities. As many as 15-20% of patients have Robin sequence.
Which of the following surgical techniques for cleft palate repair retains an anterior soft tissue pedicle for improved flap perfusion? A. von Langenbeck technique B. Furlow Z-plasty technique C. Bardach (2-flap) technique D. Pushback procedure
Answer: A
Rationale:
The von Langenbeck palate repair technique involves the creation of two full thickness mucoperiosteal flaps with care taken to preserve anterior soft tissue pedicles. The theoretical advantage of the anterior soft tissue attachments is additional blood supply for the elevated flaps. During the Bardach (2-flap) and pushback procedures, similar soft tissue flaps are elevated, but no anterior pedicle is maintained. The Furlow procedure involves the use of double opposing Z-plasties with the musculature elevated with the posteriorly based flaps on the nasal and oral sides.
In the unrepaired cleft palate, the levator veli palatini muscle inserts abnormally into: A. the medial pterygoid plate. B. the lateral pterygoid plate. C. the posterior hard palate. D. Passavant’s ridge.
Answer: C
Rationale:
The goals of cleft palate repair are twofold; first, water tight closure of the oral-nasal communication, and second, the creation of a dynamic soft palate for normal speech production. The most important muscular component of the soft palate is the levator veli palatini muscle which functions to elevate the velum and allow for appropriate speech production. In patients with an unrepaired cleft palate, the levator musculature is clefted and has abnormal insertions along the posterior edge of the hard palate.
In an infant born with a unilateral complete cleft lip and palate, primary repair of the cleft lip should be carried out when the child is:
A. 1 week of age and weighs 5 lbs (2.2kg).
B. 10 weeks of age and weighs 10 lbs (4.5 kg).
C. 10 months of age and weighs 10 lbs (4.5 kg).
D. 10 months of age and weighs 20 lbs (9.1 kg).
Answer B
Rationale:
Generally, cleft lip repair is carried out when the child is 10 to 12 weeks of age. General guidelines were developed for reduction of anesthetic risk and suggested that the surgery be undertaken when the child is approximately 10 weeks of age, weighs at least 10 lbs, and has a serum hemoglobin of at least 10 mg/dl. This has often been referred to as the “rule of 10’s” for the timing of cleft lip repair.
During primary repair of the cleft palate, utilizing Bardach’s (two-flap) technique, the palatal mucoperiosteal flaps are based upon which artery? A. Ascending pharyngeal artery B. Facial artery C. Greater palatine artery D. Sphenopalatine artery
Answer: C
Rationale:
Two-flap palatoplasty techniques involve the elevation of full-thickness mucoperiosteal flaps on each side of the cleft defect for oral side closure. After the nasal mucosa is closed, these soft tissue flaps are sutured together in the midline for closure of the cleft defect. During the initial dissection and elevation of the flaps, the greater palatine neurovascular bundles are identified and protected. The result is that the axial soft tissue flaps are raised based upon the blood supply of the greater palatine arteries bilaterally. If the greater palatine artery is injured or cauterized, then the axial pattern soft tissue flap becomes a random pattern flap (i.e. not based on one specific arterial supply) with perfusion from the palatal soft tissue attachments.
Secondary bone graft reconstruction of the cleft maxilla and alveolus is undertaken:
A. at the time of the palate repair during infancy.
B. when the maxillary central incisor is 2/3rds formed.
C. when the maxillary canine is 1⁄4 to 2/3 developed.
D. after partial eruption of the maxillary canine.
Answer: C
Rationale:
By definition, secondary bone graft reconstruction is carried out after the initial closure of the hard and soft palate. Generally, bone grafting is performed between 6 and 10 years of age, but the specific timing is based upon the child’s dental development instead of chronological age. Bone graft reconstruction of the cleft maxilla is undertaken based on the development of the permanent maxillary canine tooth. If partial eruption of the canine is allowed prior to bone graft placement, unfavorable periodontal outcome results.
The surgical technique for creation of a superiorly based pharyngeal flap requires elevation of which muscle from the posterior pharyngeal wall? A. Palatopharyngeus muscle B. Palatoglossus muscle C. Superior constrictor muscle D. Levator Veli Palatini
Answer: C
Rationale:
A superiorly based pharyngeal flap is commonly used for the management of velopharyngeal insufficiency related to cleft palate. A soft tissue flap is developed from the posterior pharyngeal wall. This is done by elevating the posterior pharyngeal wall soft tissues including the superior constrictor muscle off of the prevertebral fascia. This flap is then inset within the soft palate nasal side closure.
In the United States, the incidence of cleft lip or cleft lip with cleft palate is: A. equal among all races. B. greatest among Caucasians. C. greatest among African-Americans. D. greatest among Asian-Americans.
Answer: D
Rationale:
Cleft lip with or without cleft palate is a common congenital malformation with an incidence of approximately 1 in 700 live births, but significant variation is encountered when different ethnic/racial populations are examined. African Americans have an incidence which is significantly lower than the general population while Asians have the highest rate of birth prevalence. By contrast, isolated cleft palate has a lower overall incidence of approximately 1 in 2,000 live births with similar distribution among the different racial and ethnic populations.
The successful creation of velopharyngeal competence after superior pharyngeal flap surgery requires:
A. adequate lateral pharyngeal wall mobility.
B. palatal elongation at the time of surgery.
C. the presence of Passavant’s ridge.
D. glottic closure.
Answer: A
Rationale:
The superiorly based pharyngeal flap remains the standard approach for surgical management of patients with velopharyngeal insufficiency after cleft palate repair. The procedure involves the creation of a soft tissue flap from the posterior pharyngeal wall which is subsequently inset within the soft palate. The result is that the size of the nasopharyngeal cavity is decreased. The larger nasopharyngeal opening which could not be completely closed by the patient is instead converted into two (right and left) smaller lateral pharyngeal ports. Closure of these ports is easier for the patient to accomplish as long as adequate lateral pharyngeal wall motion is present.
Dynamic sphincter pharyngoplasty is performed by elevating myomucosal flaps which include which muscle? A. Superior constrictor muscle B. Palatopharyngeus muscle C. Palatoglossus muscle D. Tensor Veli Palatini
Answer: B
Rationale:
The dynamic sphincter pharyngoplasty procedure involves the use of two superiorly based myomucosal flaps created within each posterior tonsillar pillar. Each flap is elevated with care taken to include as much of the palatopharyngeous muscle as possible. The flaps are then attached to each other and inset within a horizontal incision on the posterior pharyngeal wall. The goal of this procedure is to create a single nasopharyngeal port that has a contractile ridge posteriorly in order to improve velopharyngeal closure.
Isolated cleft palate occurs most commonly: A. in males. B. on the right side. C. in females. D. on the left side.
Answer: C
Rationale:
In contrast to cleft lip and palate, there is a female predominance of cleft palate. The ratio is approximately 3:2.
The age at which the initial repair of a cleft palate is performed is based primarily on:
A. the anticipated development of speech.
B. the child’s ability to eat.
C. concerns for airway patency.
D. the anticipated need for bone grafting.
Answer: A
Rationale:
Ideally, one balances the need for an intact palate for normal speech production with the least interference of maxillary growth. Typically, children will begin to make purposeful speech at approximately 9 to 12 months of age. Most cleft palate centers recommend cleft palate repair between the ages of 9 and 18 months with the exact timing based upon the child’s language development as opposed to chronologic age. In a child who reaches an articulation age that requires an intact palate, failure to close the cleft leaves them vulnerable to the development of maladaptive speech patterns which are then difficult to break.
Which of the following is most appropriate in the feeding of an infant with an unrepaired cleft palate?
A. Using a squeezable bottle with a one-way valve
B. Using a reclined feeding position
C. Frequent burping of the infant
D. Fabrication of a custom feeding appliance or obturator
Answer: A
Rationale:
The presence of an unrepaired cleft palate causes difficulty with feeding due to the inability to form an adequate seal between the tongue and palate. The cleft defect prevents the infant from creating negative pressure needed to suck fluid from a bottle. Specialized feeding devices typically combine oversized nipples with reservoir spaces and large openings, a squeezable bottle to push fluid into the nipple assembly, and a one-way valve that allows the bolus of fluid to pass from the bottle to the nipple in order to minimize the amount of work the child must perform to feed. Infants should be positioned upright during feeding in order to facilitate management of the fluid bolus and secretions. Obturators for feeding have been used as feeding aids, but their value is not established. Their use has no effect on the infant’s ability to generate suction. The parent still must provide assisted feeds, and in infants with retrognathia and posteriorly positioned tongues, they create the risk of airway occlusion. Additionally, they must be monitored and adjusted frequently, making them both expensive and time consuming.
In addition to the classically described maxillomandibular anomalies, the most consistent finding associated with hemifacial microsomia is:
A. cataracts.
B. a tortuous internal carotid artery displaced toward the midline.
C. microtia.
D. a single central incisor.
Answer: C
Rationale:
Hemifacial microsomia is associated with several soft tissue anomalies in addition to the common skeletal manifestations. These include, but are not limited to, microtia, facial nerve palsy, skin tags, soft tissue and muscular hypoplasia, microphthalmos, and macrostomia.
Which of the following statements is correct regarding distraction osteogenesis of the maxilla in patients with clefts?
A. Long-term stability is greater when compared with traditional orthognathic surgery.
B. There is less likelihood of postoperative velopharyngeal insufficiency when compared with
traditional orthognathic techniques.
C. Less orthodontic finishing is required when compared with traditional orthognathic surgery.
D. Appliances are usually required to be retained for several months prior to removal.
Answer: D
Rationale:
Distraction osteogenesis has not been proven to provide significant advantages when one looks at post- operative stability or velopharyngeal insufficiency. Similar results have been seen when compared with studies done after traditional orthognathic surgery. There is no difference in orthodontic finishing requirements, and additional compensation may be required when compared with traditional techniques. During the consolidation phase, appliances (either internal or external) are kept in place for several months.
