Which of the following is the most likely diagnosis?

(A) Mandibular deficiency
(B) Mandibular excess
(C) Vertical maxillary deficiency
(D) Vertical maxillary excess

The correct response is Option D.

The findings in this patient are consistent with vertical maxillary excess, or long-face syndrome. Patients with vertical maxillary excess have increased height of the lower third of the face. This condition is characterized by labial incompetence with the lips in repose, excessive incisal show, and a lip-to-tooth relationship greater than 3 mm. Mentalis muscle strain occurs as the patient attempts to obtain labial competence. In addition, the nose and alar bases are narrowed and the nasolabial angle is obtuse. The chin is retruded and vertically long. The mandible is retrognathic, which may occur secondary to true retrognathia or backward autorotation. Occlusion is Angle class II.

Mandibular deficiency is associated with true retrognathia. Although the physical findings, such as Angle class II malocclusion and lip incompetence, are similar to vertical maxillary excess, the SNB angle is decreased in patients with mandibular deficiency.

Mandibular excess, or prognathism, is characterized by a wide lower third of the face and a full, prominent lower lip below the vermillion border. Intraoral examination shows an anterior crossbite and Angle class III malocclusion. Excessive closure of the jaws results in decreased vertical facial height. Cephalometric analysis shows an increased SNB angle.

Patients with vertical maxillary deficiency, or short-face syndrome, have decreased facial height vertically, absence of maxillary incisor show with an edentulous look, an upper lip that appears short and flat, a deep bite with an excessively protruding chin, wide alar bases, and an acute mandibular plane angle. This is Angle class III malocclusion. The SNB angle is normal or larger than normal on cephalometric analysis.

References
1. Ferraro JW. Mandibular excess and deficiency. In: Ferraro JW, ed. Fundamentals in Maxillofacial Surgery. New York, NY: Springer-Verlag; 1997:270-283.
2. Schendel SA. Vertical maxillary deformities. In: Ferraro JW, ed. Fundamentals in Maxillofacial Surgery. New York, NY: Springer-Verlag; 1997:284-286.
3. Wolford LM, Fields RT. Surgical planning. In: Booth PW, Schendel SA, Hausamen JE, eds. Maxillofacial Surgery. London, England: Churchill Livingstone, Inc; 1999;2:1205-1257.

Which of the following is the most common indication for performing distraction osteogenesis of the mandible in a 6-month-old infant?

(A) Malocclusion
(B) Mandibular hypoplasia with tongue-based airway obstruction
(C) Mandibular hypoplasia with tracheomalacia
(D) Unilateral craniofacial microsomia

The correct response is Option B.

In patients younger than age 2 years, mandibular distraction osteogenesis should only be performed when there is tongue-based airway compromise secondary to mandibular hypoplasia. In these patients, pulling the mandible forward will also pull the base of the tongue forward, relieving the airway obstruction.

Children younger than age 2 years with congenital hypoplasia or aplasia of select portions of the mandible but without airway compromise should not undergo distraction osteogenesis of the mandible because of the risk for permanent dental injury. In addition, mandibular procedures are associated with the potential for injury to the inferior alveolar nerve. Similarly, any procedures to correct malocclusion should only be performed after the permanent dentition has been established. Because children younger than age 1 year have either no dentition or rudimentary dentition and because the tooth buds are difficult to identify, operative correction of malocclusion is inappropriate.

Advancing the mandible and the base of the tongue will not relieve airway obstruction secondary to other causes, such as tracheomalacia or laryngomalacia. In neonates with these conditions, tracheotomy may be required for airway control.

Although distraction osteogenesis is typically performed in patients who have hemifacial microsomia (which can involve absence of the ramus, condyle, and/or glenoid fossa), it is only initiated in patients older than 1 year.

References
1. Cruz MJ, Kerschner JE, Beste DJ, et al. Pierre Robin sequence: secondary respiratory difficulties and intrinsic feeding abnormalities. Laryngoscope. 1999;109:1632-1636.
2. Gosain AK. Distraction osteogenesis of the craniofacial skeleton. Plast Reconstr Surg. 2001;107:278-280.
3. McCarthy JG, Stelnicki EJ, Mehrara BJ, et al. Distraction osteogenesis of the craniofacial skeleton. Plast Reconstr Surg. 2001;107:1812-1827.

A 35-year-old man comes to the emergency department because he has been unable to close his mouth since hearing a popping sound in his jaw during a wide yawn. Which of the following is the most appropriate initial management?

(A) Injection of a corticosteroid
(B) Attempted closed reduction in the emergency department under sedation
(C) Disk plication
(D) Eminectomy

The correct response is Option B.

This 35-year-old man who is unable to close his mouth has an acute open lock deformity. This condition occurs when the condyle slips into a position anterior to the articular eminence and subsequently cannot return to the normal position. The most appropriate initial step in management of this patient is attempted manual reduction, which can be performed in the emergency department. Intravenous sedation is recommended to alleviate some of the muscle spasm. If reduction in the emergency department is unsuccessful, administration of succinylcholine in the operating room is the most appropriate next step, as reduction is almost always possible with patient sedation. If this problem persists, an MRI can be obtained to help in planning osseous reduction of the articular eminence. By reducing the slope of the eminence, the condyle returns to the articular fossa more easily, relieving the open lock deformity.

Intraarticular injection of a corticosteroid will not help to reduce the articular disk into its normal position and is administered only rarely in patients with inflammation resulting from an acute open lock deformity.

Disk plication involves plication or resection of the retrodiskal tissue to shorten the tissue and position the disk posteriorly over the condyle. It is not commonly used for treatment of open lock of the mandible.

Eminectomy is not an option in patients with acute open lock deformity of the mandible.

Reference
1. Bessette RW, Jacobs JS. Temporomandibular joint dysfunction. In: Aston SJ, Beasley RW, Thorne CH, eds. Grabb & Smith’s Plastic Surgery. 5th ed. Philadelphia, Pa: Lippincott-Raven; 1997:345.

A 16-year-old girl with a history of rheumatoid arthritis has mandibular retrusion and an anterior open bite. Skeletal maturity is complete. Which of the following is most appropriate for correction of the deformity?

(A) Use of orthodontic functional appliances
(B) Advancement sagittal split osteotomy and advancement genioplasty
(C) Maxillary impaction and advancement genioplasty
(D) Maxillary impaction, advancement sagittal split osteotomy, and genioplasty

The correct response is Option C.

Because episodes of juvenile rheumatoid arthritis can be triggered by increased loading on the temporomandibular joint, orthognathic procedures should be limited to those that minimize condylar load. Therefore, the most appropriate procedure for correction of this child's deformity is maxillary impaction, which will allow closure of the open bite without creating condylar load. The resultant mandibular autorotation of the mandible will increase the SNB (sella-nasion-point B) angle, thereby correcting the mandibular deficiency. Any subsequent sagittal deficiency of the mandible can be improved with advancement genioplasty.

Orthodontic functional appliances are not effective in a 16-year-old patient and are relatively contraindicated in patients with juvenile rheumatoid arthritis because of the forces exerted on the temporomandibular joint. Mandibular advancement will result in increased condylar load, leading to degenerative remodeling.

Advancement sagittal split osteotomy is less acceptable than maxillary impaction and advancement genioplasty because it will increase condylar load.

References
1. Moore KE, Gooris PJ, Stoelinga PJ. The contributing role of condylar resorption to skeletal relapse following mandibular advancement surgery: report of five cases. J Oral Maxillofac Surg. 1991;49:448-460.
2. Proffit WR. Treatment planning: the search for wisdom. In: Proffit WR, White RP, eds. Surgical Orthodontic Treatment. Saint Louis, Mo: Mosby - Year Book; 1991:158-161.

Le Fort I osteotomy is performed through which of the following structures?

(A) Lateral orbital wall
(B) Maxillary sinus
(C) Medial orbital walls
(D) Nasofrontal junction
(E) Orbital floor

The Le Fort I osteotomy sections the maxilla transversely at a level between the roots of the teeth (note that the root of the cuspid may extend as high as the piriform rim) and the infraorbital foramen. After the lower portion of the maxilla is mobilized, movement in a number of directions is possible. A: Lengthening of the maxilla with an interpositional bone graft (not the use of miniplates for fixation). B: Shortening of the maxilla after resection of bone above the osteotomy line. C: Advancement of the maxilla. D: Segmentalization of the maxilla after down-fracture and extraction of teeth. E: Setback of the maxilla.

Reproduced with permission of Aston SJ, Beasley RW, Thorne CH, eds. Grabb & Smith’s Plastic Surgery. 5th ed. Philadelphia, Pa: Lippincott-Raven; 1997:325.

The correct response is Option B.

The Le Fort classification is used to identify the pattern of midface fractures. Identification of the lines of fracture is useful in planning osteotomies for patients requiring midface advancement.

Le Fort I midface advancement involves placement of the osteotomy at a level above the apices of the teeth. The entire alveolar processes of the maxilla, vault of the palate, and pterygoid processes are included in a single block. The osteotomy extends transversely across the base of the maxillary sinus and the floor of the piriform aperture.

The Le Fort II osteotomy begins above the level of the apices of the teeth laterally and extends through the pterygoid plates in a manner similar to the Le Fort I osteotomy, leaving a central maxillary segment undisturbed. The osteotomy procedure includes portions of the medial orbital walls, orbital floor, and nasofrontal junction. Patients undergoing Le Fort II midface advancement are at increased risk for injury to the ethmoid area and the lacrimal system. The lateral orbital wall is unaffected.

Le Fort III osteotomy extends through the zygomaticofrontal suture and the nasofrontal suture and across the orbital floor. The entire midface is completely detached from the base of the skull.

References
1. Bartlett SP, Mackay GJ. Craniosynostosis syndromes. In: Aston SJ, Beasley RW, Thorne CH, eds. Grabb & Smith’s Plastic Surgery. 5th ed. Philadelphia, Pa: Lippincott-Raven; 1997:295, 325.
2. Jackson IT, Munro IR, Salyer KE, et al. Orthognathic surgery. In: Atlas of Craniomaxillofacial Surgery. Saint Louis, Mo: CV Mosby Co; 1982:83.
3. Manson PN. Facial injuries. In: McCarthy JG, ed. Plastic Surgery. Philadelphia, Pa: WB Saunders Co; 1990;2:935-937.
4. McCarthy JG, Epstein FS, Wood-Smith D. Craniosynostosis. In: McCarthy JG, ed. Plastic Surgery. Philadelphia, Pa: WB Saunders Co; 1990; 3038.

Which of the following is the most common complication of sagittal split osteotomy?

(A) Avascular necrosis of the proximal segment
(B) Injury to the mandibular molars
(C) Loss of lower lip sensibility
(D) Nonunion of the osteotomy site
(E) Relapse from incorrect positioning of the condyles at surgery

The correct response is Option C.

The most common complication of sagittal split osteotomy is loss of lower lip sensibility. Studies have shown a significant incidence of both temporary and permanent disruption of sensibility in the lower lip following this procedure.

Sagittal split osteotomy involves only minimal muscle stripping on the lateral aspect of the mandible. The blood supply to the proximal bony segment is adequate, and the incidence of avascular necrosis is minimal.

Because the roots of the mandibular molars are closer to the lingual cortex than to the buccal cortex, they are not typically injured during osteotomy.

Nonunion is an extremely rare complication of sagittal split osteotomy.

During the osteotomy procedure, the proximal segment and condyle are seated gently into the fossa, and the surgeon takes great care to avoid displacing the condyle anteriorly and downward on the temporal bone. As a result, relapse from incorrect positioning occurs only rarely.

References
1. McCarthy JG, Kawamoto HK, Grayson BH, et al. Surgery of the jaws. In: McCarthy JG, ed. Plastic Surgery. Philadelphia, Pa: WB Saunders Co; 1990;2:1187.
2. Wolfe SA, Spiro SA, Wider TM. Surgery of the jaws. In: Aston SJ, Beasley RW, Thorne CH, eds. Grabb & Smith’s Plastic Surgery. 5th ed. Philadelphia, Pa: Lippincott-Raven; 1997:321-333.

In a patient undergoing LeFort I maxillary osteotomy and downfracture, what is the maximum bone defect (in mm) that will NOT require bone grafting?

(A) 1 mm
(B) 3 mm
(C) 5 mm
(D) 10 mm
(E) 15 mm

The correct response is Option C.

Most surgeons believe that grafting should be performed for any bone defect of the craniofacial skeleton that is larger than 5 mm. In orthognathic surgery, any movement of the Le Fort I segment in excess of 5 mm without bone graft for support is likely to result in relapse.

References
1. Gruss J, Forrest C. Acute facial fractures and secondary facial deformity. In: Bell W, ed. Modern Practice in Orthognathic and Reconstructive Surgery. Philadelphia, Pa: WB Saunders Co; 1992:1012-1055.
2. Stoelinga P. Orthognathic surgery: maxilla, Le Fort I, II, and III. In: Langdon J, Patel M, eds. Operative Maxillary Facial Surgery. New York, NY: Chapman and Hall Medical; 1998:447-461.