Corequest
Orth - 2004

A 45-year-old woman with myofascial pain dysfunction has had pain in the preauricular region for the past six months. Plain radiographs of the temporomandibular joint are most likely to show which of the following?

(A) Anterior displacement of the disk
(B) Erosion of the anterior condyle
(C) Narrowing of the joint space
(D) Osteophytes of the condylar head
(E) No abnormalities

The correct response is Option E.

In myofascial pain dysfunction, radiographs show no abnormalities because the disorder does not usually produce discernible anatomic abnormalities in the temporomandibular joint (TMJ). Myofascial pain dysfunction is associated with preauricular pain, occasional joint clicking, restricted jaw opening, and tenderness of the masticatory muscles. Its causes are multifactorial and include bruxism, anxiety, and occlusal abnormalities. Anterior displacement of the disk of the TMJ cannot be identified on plain radiographs because the disk is composed of fibrous tissue, which can be seen only on radiographs with contrast.

References:
1. Bessette RW. TMJ dysfunction. In: Achauer BM, Eriksson E, Vander Kolk C, et al, eds. Plastic Surgery: Indications, Operations, and Outcomes. Vol 2. St Louis, MO: Mosby; 2000:903.
2. Smith JW, Aston SJ, eds. Grabb and Smith’s Plastic Surgery. 4th ed. Boston, MA: Little Brown & Co; 1991:335.






A 23-year-old woman undergoes Le Fort I osteotomy with impaction of the maxilla because of vertical maxillary excess. The final vertical position of the maxilla is most accurately determined using which of the following studies?

(A) Assessment of maxillary lip-tooth relationship
(B) Cephalometric analysis of the ANB angle
(C) Cephalometric analysis of the SNA angle
(D) Dental model surgery
(E) Panorex radiography

The correct response is Option A.

Assessment of the maxillary lip-tooth relationship is the most accurate study in determining the final vertical position of the maxilla. This assessment can be made on a cephalometric radiograph by performing a soft-tissue and skeletal analysis and prediction tracing. Intraoperative assessment of the amount of tooth show is also important in determining the final vertical position of the maxilla. Normally, the lip-tooth relationship is 2 to 3 mm of tooth show.

Cephalometric analysis of the ANB and SNA angles are skeletal measurements. The ANB angle relates the maxilla to the mandible in the horizontal plane. The SNA angle relates the maxilla to the base of the cranium in the horizontal plane. Neither measurement assesses the vertical position of the maxilla or the soft-tissue envelope.

References:
1. Ferraro JW. Cephalometry and cephalometric analysis. In: Ferraro JW, ed. Fundamentals of Maxillofacial Surgery. New York: Springer-Verlag; 1997:233-245.
2. Wolford LM, Fields RT. Surgical planning. In: Booth PW, Hausamen JE, Schendel SA, eds. Maxillofacial Surgery. Vol 2. London: Churchill Livingstone; 1999:1205-1257.
3. Schendel SA. Vertical maxillary deformities. In: Ferraro JW, ed. Fundamentals of Maxillofacial Surgery. New York: Springer-Verlag; 1997:284-286.




Three weeks after undergoing bilateral maxillary advancement, a 28-year-old man has exposure of two of the four maxillary plates in the oral cavity. The maxilla appears stable. Which of the following is the most appropriate next step in management?

(A) Instruction in oral hygiene and observation
(B) Irrigation and debridement of the wound followed by replacement of the two exposed plates
(C) Maxillomandibular fixation with heavy elastic for two weeks
(D) Removal of all plates followed by intermaxillary fixation for six weeks
(E) Removal of the two exposed plates only

The correct response is Option A.

In this patient who has exposure of the internal hardware, the most appropriate management is maintenance of optimum oral hygiene. As long as oral hygiene is maintained, the oral mucosa is likely to granulate over the maxillary plates. After satisfactory bone healing has been achieved, any exposed plates can be removed.

Removal of the hardware is not indicated in a patient who underwent surgery only three weeks earlier because there is an increased risk of bony malunion. The maxilla is stable, and maxillomandibular fixation is unnecessary. The patient can continue nutrition with a soft diet without adverse sequelae.

References:
1. Gruss JS. Complications of internal fixation of the mandible. In: Yaremchuk MJ, Gruss JS, Manson PN, eds. Rigid Fixation of the Craniomaxillofacial Skeleton. Boston, MA: Butterworth Heinemann; 1992:228-229.
2. Wolfe A, Spiro S, Wider T. Surgery of the jaws. In: Aston SJ, Beasley RW, Thorne CH, eds. Grabb & Smith=s Plastic Surgery. 5th ed. Philadelphia: Lippincott Williams & Wilkins;1997:330.




The percentage of patients who have numbness in the distribution of the mental nerve one year after undergoing sagittal split osteotomy is closest to

(A) 0%
(B) 10%
(C) 30%
(D) 60%
(E) 80%

The correct response is Option B.

According to the results of several studies, the risk for permanent damage to the inferior alveolar nerve during sagittal split osteotomy is 5% to 10%. The inferior alveolar nerve exits from the mental foramen to become the mental nerve, and the incidence of permanent sensory disturbance in the distribution of the mental nerve is similar to the incidence in the inferior alveolar nerve.

References:
1. Raveh J, Vuillemin T, Ladrach K, et al. New techniques for reproduction of the condyle relation and reduction of complications after sagittal ramus split osteotomy of the mandible. J Oral Maxillofac Surg. 1988;46:751.
2. Wolfe A, Spiro S, Wider T. Surgery of the jaws. In: Aston SJ, Beasley RW, Thorne CH, eds. Grabb & Smith’s Plastic Surgery. 5th ed. Philadelphia: Lippincott Williams & Wilkins; 1997:330.




A 27-year-old man has articulation of the mesiobuccal cusp of the first upper molar with the distobuccal groove of the lower first molar. Cephalometric analysis shows increased SNB angle and negative ANB angle. Which of the following interventions are the most appropriate management of this patient’s facial deformity?

(A) Fronto-orbital advancement and Le Fort I advancement
(B) Le Fort I setback and jumping genioplasty
(C) Le Fort III advancement and mandibular advancement
(D) Maxillary impaction and vertical reduction advancement genioplasty
(E) Sagittal split osteotomy and maxillary advancement


The correct response is Option E.


This patient has mandibular prognathism, which is treated with sagittal split osteotomy (mandibular setback) and maxillary advancement. Physical examination shows Angle class III malocclusion, and cephalometric analysis shows excessive protrusion of the mandible in relation to the maxilla and base of the cranium. Although mandibular setback alone may seem to be the most logical treatment, most patients with mandibular prognathism require treatment with a combination of mandibular setback and maxillary advancement. This corrects the projecting mandible and fills the soft-tissue envelope, creating a better aesthetic result.


In a patient with mandibular prognathism, fronto-orbital advancement and Le Fort I advancement would not treat the mandibular protrusion. Le Fort I setback and jumping genioplasty also would not correct the mandibular protrusion because they do not address the mandible as a whole. Le Fort III advancement and mandibular advancement would worsen the prognathic mandible. Maxillary impaction and vertical reduction advancement genioplasty do not treat the malocclusion or mandibular skeletal abnormality.


References:
1. Wolfe SA, Bucky L. Facial osteotomies. In: Georgiade GS, Riefkohl RR, Levin LS, eds. Georgiade Plastic, Maxillofacial and Reconstructive Surgery. 3rd ed. Baltimore: Williams & Wilkins; 1997:297-337.
2. Schendel SA. Orthognathic surgery. In: Achauer BM, Eriksson E, Guyuron B, et al, eds. Plastic Surgery Indications, Operations, and Outcomes. Vol. 2. St. Louis, MO: Mosby; 2000:871-895.




A 20-year-old woman with juvenile rheumatoid arthritis has worsening occlusion two years after undergoing sagittal split osteotomy with mandibular advancement. On examination, there is a loss of posterior facial height bilaterally and an anterior open bite. She has Angle class II malocclusion. Serial cephalometric analysis shows progressive posterior movement of the B point. Which of the following is the most likely cause of the worsening occlusion?

(A) Continued growth of the maxilla
(B) Improper intraoperative seating of the condyles in the glenoid fossae
(C) Improper preoperative and postoperative orthodontic treatment
(D) Loosening of all of the plates of the rigid internal fixation
(E) Progressive condylar resorption

The correct response is Option E.

Progressive condylar resorption is a late cause of open bite that occurs mainly in young women. It is associated with condylar shortening, a decrease in posterior facial height, clockwise rotation of the mandible, and Angle class II malocclusion. Slow progressive posterior movement of the point B on serial cephalometric analysis is a classic finding. The exact cause of the problem is unknown.

Poor orthodontic treatment can result in a recurrence of malocclusion in the postoperative period. However, the patient described above exhibits many of the classic findings of progressive condylar resorption, making that a more likely diagnosis.

The most likely cause of immediate postoperative open bite is improper seating of the condyles in the glenoid fossae during surgery. It is important to take the patient out of intermaxillary fixation after fixation of the osteotomies is completed to ensure that the condyles are properly seated. During this process, the occlusion and path of the opening of the mandible are checked. In a skeletally mature female, continued growth of the maxilla would be unusual. Lastly, it would be unusual for all of the plates of the rigid internal fixation to loosen.

References:
1. Mason ME, Schendel SA. Revision orthognathic surgery. In: Booth PW, Schendel SA, Hausamen JE, eds. Maxillofacial Surgery. Vol. 2. London: Churchill Livingstone; 1999;1321-1334.
2. Sinn DP, Ghali GE. The long-term unfavorable results in orthognathic surgery. In: Kaban LB, et al., eds. Complications in Oral and Maxillofacial Surgery. Philadelphia: WB Saunders; 1997:255-264.





A 28-year-old woman who underwent Le Fort I osteotomy six weeks ago comes to the office for follow-up evaluation. She says her nose is now wider than it was before the procedure. Addition of which of the following interventions to the osteotomy procedure would have effectively minimized this adverse result?

(A) External splinting of the nose
(B) Placement of an alar cinch suture
(C) Modified Weir excision
(D) Reduction of the amount of piriform rim exposure
(E) V-Y advancement closure of the lip

The correct response is Option B.

Placement of an alar cinch suture helps decrease the degree of widening of the alar base that occurs after exposure of the anterior maxilla for orthognathic surgery or trauma management. This suture is placed in the base of the ala bilaterally and then is tightened until the desired effect is achieved.

External splinting of the nose has no effect on dimensional changes of the nasal ala. Although a modified Weir excision is designed to treat alar flare, it does not address the increased width of the alar base seen after Le Fort I osteotomy. Reduction of piriform rim exposure is not appropriate for this patient. During Le Fort I osteotomy, complete exposure of the piriform rim is essential because the rim serves as a landmark from which to measure movement in the maxilla. Also, the bone in the piriform rim and the malar buttress provides a stable platform for rigid fixation.

V-Y advancement is used during oral mucosal closure, especially after Le Fort I osteotomy, which tends to flatten the upper lip. This suture technique advances the tissue anteriorly to add fullness to the upper lip, but has no effect on nasal width.

References:
1. Betts NJ. Techniques to control nasal features. Atlas Oral Maxillofac Surg Clin Am. 2000;8:53-69.





Which of the following orthognathic movements is the most unstable and prone to relapse?

(A) Mandibular advancement
(B) Mandibular narrowing
(C) Maxillary advancement
(D) Maxillary widening
(E) Sliding genioplasty


The correct response is Option D.


Transverse widening of the maxilla is the most unstable orthognathic movement. With this procedure, a patient may lose as much as 50% of the movement at one year after surgery. Maxillary downgrafts and mandibular setbacks are also relatively unstable procedures. Mandibular advancement, mandibular narrowing, maxillary advancement, and sliding genioplasty are all considered stable movements.


References:
1. Philips C, Medland WH, Fields HW, et al. Stability of surgical maxillary expansion. Int J Adult Orthop Orthogn Surg. 1992;7:139-146.
2. Proffit WR, Phillips C. Physiologic responses to treatment and postsurgical stability. In: Proffit WR, White RP, Sarver DM, eds. Contemporary Treatment of Dentofacial Deformities. St. Louis, MO: Mosby; 2003:646-676.




In patients with vertical maxillary excess undergoing Le Fort osteotomy with maxillary impaction, which of the following findings is most likely postoperatively?

(A) Increased mentalis strain
(B) Increased upper incisal show
(C) More obtuse nasolabial angle
(D) Retrogenia
(E) Widened alar base

The correct response is Option E.

Patients with vertical maxillary excess, or long-face syndrome, have a narrow alar base, an obtuse nasolabial angle, and an anterior open bite. Mentalis muscle strain and labial incompetence are increased, and there is excess gingival show and exposure of the upper incisors.

Appropriate management is Le Fort I osteotomy with maxillary impaction; osseous genioplasty is also performed in some patients. These procedures will correct many of the findings associated with this condition, including decreasing the mentalis muscle strain and incisal show and creating a more acute nasolabial angle. The alar base will be widened. Le Fort I osteotomy also rotates the mandible forward and upward, resolving the retrogenia associated with long-face syndrome. Postoperative lateral cephalograms will show forward autorotation of the mandible with counterclockwise rotation.

References:
1. McCarthy JG, Kawamoto HK, Grayson BH, et al. Surgery of the jaws. In: McCarthy JG, ed. Plastic Surgery. Vol. 2. Philadelphia: WB Saunders; 1990;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: Lippincott-Raven; 1997:321-333.





In patients with Treacher Collins syndrome, which of the following is a characteristic skeletal finding?

(A) Brachycephaly
(B) Hypertelorism
(C) Macrogenia
(D) Malar hypoplasia
(E) Preaxial polysyndactyly

The correct response is Option D.
The characteristic skeletal finding in patients with Treacher Collins syndrome is hypoplasia of the malar bones, which often occurs in conjunction with clefting through the zygomatic arches. Patients also have hypoplasia of the maxilla and mandible and antegonial notching of the angle of the mandible. Occlusion is Angle class II; there is an anterior open bite and clockwise rotation of the occlusal plane. Effects on the temporomandibular joint are varied.

Brachycephaly, macrogenia, preaxial polysyndactyly, and hypertelorism do not occur in patients with Treacher Collins syndrome.


References:
1. Marsh JL, Celin SE, Vannier MW, et al. The skeletal anatomy of mandibulofacial dysostosis (Treacher Collins syndrome). Plast Reconstr Surg. 1986;78:460.
2. Posnik JC. Treacher Collins syndrome. In: Aston SJ, Beasley RW, Thorne CH, eds. Grabb & Smith’s Plastic Surgery. 5th ed. Philadelphia: Lippincott Williams & Wilkins; 1997:313.