In-Service Exam
Maxillo - Facial - 2003





A 38-year-old man sustains panfacial fractures in a motor vehicle collision. On physical examination, the midface is unstable. Radiographs show bilateral displaced fractures of the condylar neck. Which of the following of the most appropriate management?

(A) Open reduction and internal fixation of the midface fractures followed by a soft diet for four weeks
(B) Open reduction and internal fixation of the midface fractures followed by placement of a mandibular external fixator
(C) Open reduction and internal fixation of the midface fractures followed by intermaxillary fixation of the mandible
(D) Open reduction and internal fixation of the condylar neck fractures followed by open reduction and internal fixation of the midface fractures
(E) Open reduction and internal fixation of the midface fractures followed by open reduction and internal fixation of the condylar neck fractures

The correct response is Option D.

In this patient who has fractures of the midface and condylar neck, the most appropriate management is open reduction and internal fixation of the condylar fractures, followed by open reduction and internal fixation of the midface fractures. Reducing the mandible first is the only method for reestablishing the appropriate height of the posterior face; the midface can then be repaired using the mandible as a reference.

Conservative measures, such as initiation of a soft diet without fixation of the mandible, are not appropriate in patients with fractures of the condylar neck. External fixators are typically applied in patients who have comminuted fractures of the mandible, or when early open reduction and internal fixation are not possible, such as in patients who are medically unstable and cannot undergo surgical procedures.

References
1. Larson PE. Traumatic injuries of the condyle. In: Peterson LJ, ed. Oral and Maxillofacial Surgery. Philadelphia, Pa: JB Lippincott Co: 1992;1:435-469.
2. Wolfe SA, Baker S. Facial Fractures. New York, NY: Thieme Medical Publishers, Inc; 1993:41-61.

A 24-year-old woman undergoes Le Fort I osteotomy with maxillary impaction and bilateral sagittal split osteotomy with mandibular advancement. Following release of intermaxillary fixation six weeks later, the patient has an anterior open bite. Which of the following is the most likely cause of this finding?

(A) Improper intraoperative seating of the condyles in the glenoid fossae
(B) Improper presurgical orthodontic treatment
(C) Loosening of all plates of the rigid internal fixation
(D) Parafunctional habits, such as tongue thrusting
(E) Progressive resorption of the condyles

The correct response is Option A.

This patient's anterior open bite, seen six weeks after surgery, is most likely a result of improper intraoperative seating of the condyles in the glenoid fossae. Once the osteotomy has been completed, it is important to release the patient from intemaxillary fixation in order to ensure that the condyles are properly seated within the fossae. The occlusion and path of the opening of the mandible are examined at this time.

Improper presurgical orthodontic treatment would result in a late recurrence of malocclusion. It is unlikely that all of the plates of the rigid internal fixation would loosen over the six-week fixation period. Parafunctional habits, such as tongue thrusting, are a late cause of anterior open bite. Progressive condylar resorption, which manifests as condylar shortening, decreased height of the posterior face, and clockwise rotation of the mandible, is a late cause of open bite occurring primarily in young women. The cause of this condition is unknown.

References
1. Mason ME, Schendel SA. Revision orthognathic surgery. In: Booth PW, Schendel SA, Hausamen JE, eds. Maxillofacial Surgery. London, England: Churchill Livingstone, Inc; 1999;2:1321-1334.
2. McCarthy JG, Kawamoto HK, Grayson BH, et al. Surgery of the jaws. In: McCarthy JG, ed. Plastic Surgery. Philadelphia, Pa: WB Saunders Co; 1990;2:1188-1474.

PHOTO

The photograph and CT scan shown above are from a 25-year-old man who sustained maxillofacial injuries in a motor vehicle collision. Physical examination shows telecanthus and impaction of the bridge of the nose. Which of the following is the most appropriate management?

(A) Observation
(B) Closed reduction and external fixation
(C) Open reduction and internal fixation with delayed bone grafting
(D) Open reduction and internal fixation with immediate bone grafting
(E) Delayed reconstruction three months after injury
The correct response is Option D.

In this patient who has a naso-orbitoethmoid fracture, the most appropriate management is open reduction and internal fixation of the fracture with immediate bone grafting. Naso-orbitoethmoid injuries typically include fractures of the nasal bones and frontal processes of the maxilla; the medial canthal attachments and lacrimal system can also be damaged. Associated findings include telecanthus (ie, widening of the intercanthal distance), impaction of the nasal bridge with shortening of the nose, and hematomas of the eyelids. In patients with involvement of the medial canthi, there may be asymmetry of the canthi, blunting of the canthal angle, and movement of the canthus when the eyelid is pulled laterally.

Because these fractures are highly complex and often comminuted, open reduction and internal fixation with immediate bone grafting are advocated. Bone grafting will maintain the soft-tissue expansion of the nasal tip, resulting in a more normal appearance of the tip.

Observation is not acceptable in a patient who has impaction of the nasal bridge and marked comminution of the nasal bones on CT scan. If the fracture is not reduced immediately, the patient will have deformities of the nose and midface following resolution of the swelling.

Closed reduction and fixation using lead plates and transnasal wires as an external splint may be difficult in patients with naso-orbitoethmoid fractures. The comminuted fracture fragments are difficult to incorporate within the transnasal wiring in such a way that the elevation of the fragments will be maintained. In addition, medial canthal injuries are usually not corrected adequately with closed reduction.

Performing bone grafting as a delayed procedure will most likely result in increased complications during surgery because the soft-tissue envelope may contract and may not be amenable to expansion with insertion of the graft. As a result, the graft may perforate the skin. Immediate bone grafting will allow for definitive one-stage repair; in addition, postoperative traumatic deformities may be difficult to correct at a later date.

References
1. Ayliffe P, Booth PW. Nasoethmoid fractures. In: Booth PW, Schendel SA, Hausamen JE, eds. Maxillofacial Surgery. London, England: Churchill Livingstone, Inc; 1999;1:141-159.
2. Crawley WA, Vasconez HO. Midface, upper face, and panfacial fractures. In: Ferraro JW, ed. Fundamentals in Maxillofacial Surgery. New York, NY: Springer-Verlag; 1997:203-214.
3. Lettieri S. Facial trauma. In: Achauer BM, Erikson E, Guyuron B, et al, eds. Plastic Surgery: Indications, Operations, and Outcomes. Saint Louis, Mo: Mosby Ð Year Book, Inc; 2000;2:923-940.
4. Manson PN. Facial fractures. In: Aston SJ, Beasley RW, Thorne CH, eds. Grabb & Smith's Plastic Surgery. 5th ed. Philadelphia, Pa: Lippincott-Raven; 1997:383-412.

A 24-year-old man is brought to the emergency department after being struck in the face. CT scan of the face shows an orbital blow-out fracture. Which of the following findings is an indication for operative intervention?

(A) Blood in the maxillary sinus
(B) Diplopia on primary gaze
(C) Hypesthesia in the infraorbital nerve distribution
(D) Orbital floor defect greater than 2 cm
(E) Subconjunctival hematoma

The correct response is Option D.

In a patient who has sustained an orbital blow-out fracture, indications for surgical exploration include an orbital floor defect of greater than 2 cm, abnormally low vertical height of the globe, and the presence of other fractures. Operative exploration should be performed in patients who have symptomatic diplopia in association with positive findings on forced duction testing. Patients who have symptoms of extraocular muscle entrapment that do not resolve in one week or indications of muscle entrapment on radiographs obtained one week after surgery should undergo additional exploration.

Diplopia on primary gaze typically improves within the first two weeks after surgery. The presence of blood in the maxillary sinus and hypesthesia in the distribution of the infraorbital nerve is common in patients with minor orbital fractures, and surgical intervention is not required. Likewise, subconjunctival hematoma is not an indication for operative intervention.References
1. Grossman MD, Roberts DM, Barr CC. Ophthalmic aspects of orbital injury: a comprehensive diagnostic and management approach. Clin Plast Surg. 1992;19:71.
2. Manson PN. Facial fractures. In: Aston SJ, Beasley RW, Thorne CH, eds. Grabb & Smith's Plastic Surgery. 5th ed. Philadelphia, Pa: Lippincott-Raven; 1997:383-412.
3. Manson PN, Ilif N. Management of blow out fractures of the orbital floor. Surg Ophthalmol. 1991;35:280-292.

An 18-year-old man has a displaced fracture of the anterior table of the frontal sinus. Which of the following statements is most accurate regarding glue fixation of this fracture using butyl-2-cyanoacrylate?

(A) Facial bone healing will be partially impeded
(B) Glue fixation is more time consuming than plate and screw fixation
(C) Glue fixation will provide compressive forces comparable to either resorbable or titanium plate and screw fixation
(D) The glue will not adhere to a moist bone surface
(E) Inflammation resulting from breakdown products of butyl-2-cyanoacrylate will lead to scarring and possible brain damage

The correct response is Option C.

According to the results of in vitro studies, plate and screw fixation devices have been shown to tolerate higher distraction forces than glue fixation. Plates and screws also provide greater biomechanical stability than butyl-2-cyanoacrylate in bones, such as the mandible, that absorb large forces. However, in the thin bone fragments of the anterior table of the frontal sinus, which are affected by small compressive forces, butyl-2-cyanoacrylate has been shown to provide fixation stability that is comparable to either resorbable or titanium plate and screw fixation. In addition, fixation of the thin bone fragments of this region is limited by the pull-out strength of the screws to the applied bone segments, which is not significantly greater than the adhesive strength of cyanoacrylate to bone.

Facial bone healing is not impeded by cyanoacrylates; instead, according to the results of some studies, healing is believed to be augmented.

Use of tissue adhesives requires less operative time than fixation with plates and screws. Cyanoacrylates set within seconds, and the need to contour plates accurately is eliminated.

Bone surfaces are often moist intraoperatively, and cyanoacrylates will adhere to these moist surfaces.

Inflammation is rare in the tissues adjacent to those exposed to butyl-2-cyanoacrylate or its breakdown products; harmful side effects are minimal. Damage to the underlying brain was not shown to occur in animal studies in which cyanoacrylate was used for cranial fixation.

References
1. Gosain AK, Lyon VB. Use of tissue glue: current status. Perspectives in Plastic Surgery. 2001;15:129-145.
2. Gosain AK, Song L, Corrao MA, et al. Biomechanical evaluation of titanium, biodegradable plate and screw, and cyanoacrylate glue fixation systems in craniofacial surgery. Plast Reconstr Surg. 1998;101:582-591.
3. Shermak MA, Wong L, Inoue N, et al. Butyl-2-cyanoacrylate fixation of mandibular osteotomies. Plast Reconstr Surg. 1998;102:319-324.

In a patient who has sustained a fracture of the zygomaticomaxillary complex, which of the following anatomic structures is most useful for reduction of the fracture components?

(A) Inferior orbital rim
(B) Lateral orbital wall
(C) Orbital floor
(D) Zygomatic arch
(E) Zygomaticomaxillary plane

The correct response is Option B.

In a patient who has sustained a fracture of the zygomaticomaxillary complex, the lateral orbital wall and the sphenoid wing can be used as landmarks to obtain the most accurate reduction. Visualization of these structures from inside the orbit will allow for visualization of the relatively flat plane of the orbital portion of the zygoma and the relatively flat portion of the sphenoid wing. An appropriate anatomic reduction is attained when these two areas are smoothly aligned.

Although the inferior orbital rim, orbital floor, zygomatic arch, and zygomaticomaxillary plane can be useful landmarks for individual alignment, use of any of these sites for reduction of the zygomaticomaxillary complex will result in significant rotational malalignment at the other fracture sites.

References
1. Kelly KJ. Pediatric facial trauma. In: Vander Kolk CA, ed. Plastic Surgery: Indications, Operations, and Outcomes. Saint Louis, Mo: Mosby Ð Year Book, Inc; 2000;2:941-969.
2. Manson PN. Facial injuries. In: McCarthy JG, ed. Plastic Surgery. Philadelphia, Pa: WB Saunders Co; 1990;2:867-1141.

Which of the following structures is incised when a preseptal transconjunctival incision is performed in patients with fractures of the orbital floor?

(A) Capsulopalpebral fascia
(B) Levator palpebrum
(C) Orbicularis oculi muscle
(D) Orbital septum
(E) Tarsus

The correct response is Option A.

The preseptal transconjunctival incision has been used with increasing frequency in recent years because any associated scars are better concealed and the risk for eyelid retraction is lower than with transcutaneous approaches. With this technique, the incision is made through the conjunctiva below the tarsus of the lower eyelid. The capsulopalpebral fascia (retractors of the lower eyelid) is incised and the plane between the orbicularis oculi muscle and the septum is entered. The periosteum of the orbital rim is then incised to expose the fracture.

The levator palpebrum, an elevator of the upper eyelid, is not involved in repair of orbital floor fractures.
References
1. Silkiss RZ, Carroll RP. Transconjunctival surgery. Ophthalmic Surg. 1992;23:288-291.
2. Westfall CT, Shore JW, Nunery WR, et al. Operative complications of the transconjunctival inferior fornix approach. Ophthalmology. 1991;98:1525-1528.

A patient has dilation of the right pupil immediately after undergoing open reduction and internal fixation of an orbitozygomatic fracture on the right. On examination, the right pupil is unresponsive to direct light stimulation, and there is no consensual response to light.

These findings are best explained by injury to which of the following structures?

(A) Globe
(B) Optic nerve
(C) Ocular parasympathetic nerves
(D) Ocular sympathetic nerves
(E) Trochlear nerve

The correct response is Option C.

Complete inability to constrict the right pupil associated with absence of direct and consensual responses to light is most likely caused by compromised function of the ocular parasympathetic innervation. Because the parasympathetic fibers travel with the oculomotor nerve and inferior oblique muscle, they can be injured during reduction or fixation of fractures in the region of the orbit and zygoma, especially with manipulation of the muscle. Use of topical mydriatic agents, such as epinephrine, can also result in these findings.

Fixed dilation of the pupil would not occur in a patient who sustained injury to the globe. Trauma to the optic nerve would result in a relative afferent pupillary defect, in which the affected eye cannot perceive light. In patients with this finding, known as a Marcus-Gunn pupil, direct response to light is impaired, but consensual response is preserved. Injury to the ocular sympathetic nerves would disrupt the dilatory reflex of the pupil, while injury to the trochlear (IV) nerve would affect the actions of the superior oblique muscle.

References
1. Bodker FS, Cytryn AS, Putterman AM, et al. Postoperative mydriasis after repair of orbital floor fracture. Am J Ophthalmology. 1993;115:372-375.
2. Stromberg BV, Knibbe M. Anisocoria following reduction of bilateral orbital floor fractures. Ann Plast Surg. 1988;21:486-488.

Patients with displaced zygomatic fractures are most likely to have which of the following findings at the palpebral fissure?

(A) Anterior displacement
(B) Downward cant
(C) Posterior displacement
(D) Rounding
(E) Upward tilt

The correct response is Option B.

Fractures of the orbitozygomatic complex most commonly have break lines through the midinfraorbital rim that extend into the orbital floor and lateral orbital wall along the zygomaticosphenoid suture and end toward the zygomaticofrontal suture. Complete fractures have break lines that extend from the infraorbital rim through the zygomaticomaxillary buttress inferiorly and zygomatic arch laterally. Fractures of the orbitozygomatic complex can be displaced en bloc or rotationally; most displaced zygomatic fractures are depressed and rotated laterally. In patients with displaced, laterally rotated fractures of the orbitozygomatic complex, the lateral canthus attached to Whitnall's tubercle pulls the palpebral fissure into a downward cant. This finding is also seen in patients with medially rotated fractures because the unopposed pull of the attached masseter muscle contributes to downward movement of the zygoma. Lateral displacement of the lateral canthal ligament is also associated with this downward movement, leading to an increase in the width of the fissure.

There is no substantial anterior or posterior displacement of the palpebral fissures with fractures of the orbitozygomatic complex.

Rounding of the palpebral fissure can occur with the less common en bloc type of medial displacement but is more frequent with detachment of the lateral canthal ligament or with a severely comminuted fracture of the frontal process of the zygoma.

The fracture patterns associated with orbitozygomatic complex fractures would not result in upward displacement of Whitnall's tubercle.

References
1. Antonyshyn O. Principles in management of facial injuries. In: Georgiade GS, Riefkohl R, Levin LS, eds. Textbook of Plastic, Maxillofacial and Reconstructive Surgery. 3rd ed. Baltimore, Md: Williams & Wilkins; 1997:339-350.
2. Lettieri S. Facial trauma. In: Achauer BM, Erikson E, Guyuron B, et al, eds. Plastic Surgery: Indications, Operations, and Outcomes. Saint Louis, Mo: Mosby Ð Year Book, Inc; 2000;2:923-940.
3. Manson P. Facial fractures. In: Aston SJ, Beasley RW, Thorne CH, eds. Grabb & Smith's Plastic Surgery. 5th ed. Philadelphia, Pa: Lippincott-Raven; 1997:383-412.
4. Manson PN. The management of midfacial and frontal bone fractures. In: Georgiade GS, Riefkohl R, Levin LS, eds. Textbook of Plastic, Maxillofacial and Reconstructive Surgery. 3rd ed. Baltimore, Md: Williams & Wilkins; 1997:351-376.