Maxillofacial

Question 1

A 50-year-old man comes to the office for revision of a bony defect in the skull 1 year after undergoing cranioplasty. Physical examination shows a 4 × 4-cm depression in the skull. Reconstruction with methyl methacrylate is planned. Which of the following properties is the primary advantage of the use of methyl methacrylate over other biomaterials?
A) Bony ingrowth
B) Easy prefabrication
C) Endothermic
D) High strength
E) Resistance to infection

Answer 1

D) High strength

Methyl methacrylate has a high compression strength.This biomaterial has been used extensively for reconstruction of traumatic skull defects. The material is formed by mixing powdered polymer with liquid monomer. The reaction is highly exothermic. Advantages to its use include low cost, increased strength (relative to surrounding bone), and ready availability. Methyl methacrylate does not demonstrate bony incorporation or ingrowth. This property makes it susceptible to infection throughout the duration of the reconstruction. Although it is an appropriate choice for reconstruction of defects in adults, the product is inert and fixed; therefore, it does not adapt with growth in children. Methyl methacrylate can be prefabricated, but it requires complex planning.

Question 2

Strength of methyl methacrylate

Answer 2

High compression strength

Question 3

Reconstruction with methyl methacrylate

Answer 3

Powdered polymer is mixed with liquid monomer, creating a highly exothermic reaction.

Question 4

Why is methyl methacrylate susceptible to infection?

Answer 4

It does not demonstrate bony incorporation nor ingrowth

Question 5

Pros / cons of methyl methacrylate

Answer 5

Pros: Low cost, increased strength (relative to surrounding bone), and ready availability.

Cons: Does not demonstrate bony ingrowth (susceptible to infection), inert/fixed (does not adapt to growth in children), exothermic reaction

Question 6

A 72-year-old man is brought to the emergency department after he sustained injuries in a high-speed motor vehicle collision as an unrestrained backseat passenger. He has chronic obstructive pulmonary disease and a 40-pack-year history of smoking. The following measurements are obtained:

Heart rate 88 bpm
Respirations 18/min
Blood pressure 115/70 mmHg
Oxygen saturation 98% on 6 L by face mask

Physical examination shows severe swelling in the face. He is coughing blood and mucus from his mouth and nose. Gross malocclusion is noted, but full dentition is present with no dental caries. CT scan shows a naso-orbital-ethmoid fracture, Le Fort III fracture, palatal fracture, and comminuted mandibular body and angle fractures. Which of the following is the most appropriate method of airway management during surgical repair of this patient’s fractures?
A) Cricothyroidotomy
B) Nasotracheal intubation
C) Placement of an orotracheal tube
D) Tracheostomy
E) Use of a laryngeal mask airway

Answer 6

D) Tracheostomy

The patient described has complex facial fractures involving both the midface and the lower face. He also has a significant history of smoking. This particular patient is likely to have continued respiratory issues postoperatively, making pulmonary management challenging. The placement of a tracheostomy at the time of surgery will allow the surgical team full access to all of the patient’s facial fractures and will facilitate the patient’s pulmonary care postoperatively.

Nasotracheal intubation is contraindicated in a patient with a naso-orbital-ethmoid fracture because the presence of a tube can complicate fracture reduction.Generally, placement of an orotracheal tube is feasible and successful in most facial fracture patients. However, given the complex nature of fractures in the scenario described, the patient will need to be placed into mandibular-maxillary fixation during surgery to obtain normal occlusion and possibly for an indefinite period of time after surgery.

Question 7

Indication for cricothyroidectomy

Answer 7

Cricothyroidotomy is indicated occasionally as an emergency procedure when there is concern for acute control of the patient’s airway.

Question 8

A 22-year-old man is brought to the emergency department after sustaining injuries during an all-terrain vehicle collision. Clinical examination shows telecanthus and periorbital ecchymosis. A fracture dislocation involving which of the following structures is most likely contributing to the telecanthus?
A) Inferior rectus muscle tendon
B) Lateral canthal tendon
C) Lateral rectus muscle tendon
D) Medial canthal tendon
E) Medial rectus muscle tendon

Answer 8

D) Medial canthal tendon

Question 9

The medial canthal tendon attaches to:

Answer 9

The medial canthal tendon is a fibrous band attached to the medial orbital wall (frontal bone and lacrimal crest).

Question 10

A 42-year-old woman is brought to the emergency department after sustaining traumatic fractures of the right orbit and zygoma in a motor vehicle collision. Physical examination shows localized edema. Which of the following indications is most likely for immediate ophthalmologic consultation?
A) Corneal abrasion
B ) Diplopia 
C) Eyelid ptosis
D) Hyphema
E) Subconjunctival hemorrhage

Answer 10

D) Hyphema

Hyphema is defined as blood within the anterior chamber of the eye. It is caused by tearing of the vessels within the iris as a result of trauma.

Neither diplopia nor traumatic ptosis warrantsemergent consultation.

Question 11

Hyphema

Answer 11

Hyphema is defined as blood within the anterior chamber of the eye. It is caused by tearing of the vessels within the iris as a result of trauma.

Blood within the eye is worrisome because clotting can interfere with fluid egress from the anterior chamber, leading to the development of glaucoma. Immediate ophthalmology consultation, urgent intraocular pressure measurement, andslit-lamp examination should be performed to determine the extent of hemorrhage.

Question 12

Subconjunctival hemorrhage

Answer 12

Subconjunctival hemorrhage, on the other hand, stains the bulbar conjunctiva with blood from the site of a nearby fracture.

Question 13

A 24-year-old man comes to the office for follow-up examination 2 weeks after undergoing open reduction and internal fixation of a fracture of the right zygomaticomaxillary complex. The procedure was performed with intraoral and subtarsal eyelid incisions. Physical examination shows ectropion of the right lower eyelid. Ophthalmologic examination shows no vision abnormalities; the cornea is intact. Which of the following is the most appropriate management of the ectropion?
A) Coverage with a tarsoconjunctival flap
B) Lateral canthoplasty
C) Placement of an allograft to the middle lamella
D) Skin grafting to the external lamella
E) Observation with massage

Answer 13

E) Observation with massage

Conservative therapy is recommended and includes tarsorrhaphy, massage, and application of ophthalmic steroid ointment or drops.

Question 14

What percent of patients will require operative revision for globe or eyelid malposition after orbital fracture reconstruction?

Answer 14

Complications related to the eyelid are common following orbital fracture reconstruction. Approximately 10 to 20% of patients will require some operative revision for globe or eyelid malposition. This is because of the edema and swelling present at the initial operation. As a result, the incidence of scleral show and ectropionis also high because of eyelid retraction.

Conservative therapy is recommended and includes tarsorrhaphy, massage, and application of ophthalmic steroid ointment or drops.

Question 15

A 20-year-old man comes to the office with severe malocclusion 8 weeks after sustaining injuries during a motor vehicle collision. Physical examination shows healing lacerations, loss of sensation in the infraorbital nerve distribution on the affected side, and no orbital rim step-off deformity. CT scan shows a unilateral orbital blowout fracture with a mid face fracture. No mandibular fracture is identified. Which of the following is the most appropriate initial step in management?
A) Le Fort I osteotomy with fixation
B) Maxillomandibular fixation
C) Open reduction and internal fixation of the ZMC fracture
D) Open reduction and reconstruction of the orbital floor fracture

Answer 15

A) Le Fort I osteotomy with fixation

Because the patient is 8 weeks out from the injury, the fracturelines are immobile and a Le Fort I osteotomy and maxillomandibular fixation would be required to correct the malocclusion.

Question 16

A 27-year-old man is brought to the emergency department 1 hour after sustaining a knife wound to the left cheek. Physical examination shows a wound just anterior to the left ear that extends intraorally. A photograph is shown. He is able to elevate the brow, close the eyes, smile, and evert the lower lip. The laceration is irrigated thoroughly. Which of the following is the most appropriate next step in management?
A) Application of wet-to-dry dressings
B) Cannulation of Stensen duct
C) Closure of the facial wound and administration of sialogogues
D) Starch-iodine test
E) Testing of the distal branches of the facial nerve with a stimulator

Answer 16

B) Cannulation of Stensen duct

After ruling out facial nerve injury, the next priority in management of a cheek laceration is to rule out injury to the parotid (Stensen) duct. Failure to repair a parotid duct laceration can result in a salivary fistula or sialocele.

is not necessary to explore the facial nerve when the patient has clinically intact facial motor function. Such exploration risks inadvertent injury to the nerve.

Question 17

Failure to repair a parotid duct laceration can result in:

Answer 17

Failure to repair a parotid duct laceration can result in a salivary fistula or sialocele.

Question 18

How is injury to the parotid duct ruled out?

Answer 18

A small amount of methylene blue dye injected via an intravenous catheter, introduced through the ductal papilla in the mouth opposite the maxillary second molar, may be effective in identifying lacerations.

Question 19

Name of the parotid duct

Answer 19

Stensen duct

Question 20

How is injury to the parotid duct repaired?

Answer 20

Whenever possible, it is best to repair lacerations primarily using fine suture (eg, 8-0 nylon) over a stent.
If the duct cannot be repaired because of extensive damage, ligation of the duct can be considered

Question 21

Salivation vs a parotid/parotid duct injury

Answer 21

Anticholinergic medications, such as glycopyrrolate, can be administered to limit salivary secretion during healing and to help prevent salivary fistula or sialocele formation from an unrecognized ductal injury or glandular laceration.

Question 22

Starch-iodine test

Answer 22

The starch-iodine test is used to assess gustatory sweating thought to occur because of inappropriate sympathetic reinnervation of the facial sweat glands after parotid surgery.

Question 23

Avulsions occur most commonly at which of the following layers of the scalp?
A) Aponeurotic layer
B) Loose areolar layer
C) Pericranium
D) Skin
E) Subcutaneous layer

Answer 23

B) Loose areolar layer

Question 24

Layers of the scalp

Answer 24

The layers of the scalp can be remembered by the mnemonic SCALP: skin, subcutaneous tissue, aponeurotic layer (also called the galea), loose areolartissue, and pericranium.

Question 25

Associations of layers of the scalp

Answer 25

The skin, subcutaneous tissue, and galea are intimately fused and move as a unit. These layers are separated from the pericranium by a layer of areolar tissue. This layer allows easy movement of the scalp and provides a space for fluid accumulation.

Question 26

Avulsions occur most commonly at which of the layers of the scalp?

Answer 26

Loose areolar layer The other layers of the scalp are separated from the pericranium by a layer of areolar tissue. This layer allows easy movement of the scalp and provides a space for fluid accumulation. It is through this layer that separation most easily occurs in the setting of trauma to or surgical reflection of the scalp.

Question 27

What crosses the loose areolar layer of the scalp / clinical significance?

Answer 27

Emissary veins cross the loose areolar space as they drain the scalp into the intracranial venous sinuses. Because of the potential for accumulation of fluid in the loose areolar tissue, an infection or abscess in this layer may lead to meningitis or septic venous sinus thrombosis. However, the incidence of such events is low.

Question 28

What is considered the strength layer of the scalp?

Answer 28

The galeal aponeurosis is considered the strength layer of the scalp

Question 29

What is the galeal aponeurosis continuous with?

Answer 29

The galeal aponeurosis is considered the strength layer of the scalp and is contiguous with the frontalis and occipitalis muscles and the temporoparietal fascia laterally.

Question 30

Blood supply to the pericranium

Answer 30

The pericranium is tightly adherent to the skull. It derives its blood supply from the diploic circulation via a multitude of perforating blood vessels and can serve as a vascularized bed for accepting skin grafts.

Question 31

A 22-year-old man is brought to the emergency department after sustaining injuries to the head during a high-speed motor vehicle collision. Examination shows fluid draining from the nostrils. Beta-2 transferrin test on the fluid is positive. CT scan shows a frontal sinus fracture. The anterior and posterior tables are nondisplaced. Which of the following is the most appropriate next step? A) Cranialization of the frontal sinus B) Dural repair C) Obliteration of the frontal sinus D) Reduction and fixation of the anterior-table frontal sinus E) Observation

Answer 31

E) Observation A positive beta-2 transferrin test result indicates a cerebrospinal fluid (CSF) rhinorrhea. The first priority is to seal the leak. The patient should be observed before proceeding. The head of the bed should be elevated, and consideration should be given to placement of a lumbar CSF drain. If the leak does not resolve, surgical intervention should be planned.Once the CSF rhinorrhea has resolved, operative repair of the facial fractures can begin. After the premorbid occlusion is established, the mandible fractures are plated sequentially. Cranialization is reserved for displaced posterior table frontal sinus fractures. Dural repair is not needed at this stage as the CSF leak will probably seal on its own. Obliteration of the frontal sinus may be required if the CSF rhinorrhea fails to respond to conservative treatmen

Question 32

Beta-2 transferin test

Answer 32

A positive beta-2 transferrin test result indicates a cerebrospinal fluid (CSF) rhinorrhea.

Question 33

Indication for cranialization of the frontal sinus

Answer 33

Cranialization is reserved for displaced posterior table frontal sinus fractures.

Question 34

A 25-year-old man comes to the office for a follow-up examination because he has had intraoral drainage and pain and swelling over the right mandible for the past 24 hours. Ten days ago, he underwent maxillomandibular fixation followed by rigid internal fixation. CT scan of the head shows a soft-tissue collection along the right mandibular body; there is no evidence of osteomyelitis, and the rigid fixation is stable. Which of the following is the most appropriate management? A) Incision and drainage B) Incision and drainage, removal of hardware, andexternal fixation C) Incision and drainage, removal of hardware, and maxillomandibular fixation D) Incision and drainage, removal of hardware, and vascularization of fibula flap transfer E) No additional intervention is needed

Answer 34

A) Incision and drainage Management of these infections requires adequate incision and drainage as well as intravenous antibiotics and mouth care. If the source of infection is an exposed infected tooth root, it should be removed. It is important that rigid internal fixation be maintained until the bone fracture segments have ossified because nonrigid fixation, such as external fixation ormaxillomandibular fixation, can lead to worsening of infection.Removal of the internal hardware is rarely necessary unless the hardware is actively infected and loosened because of bone involvement (osteomyelitis).Repair with vascularized fibula flap transfer is also not indicated because there is no evidence for osteomyelitis or extensive bone loss.

Question 35

What is the most common complication after mandibular fracture repair?

Answer 35

Postoperative infections are the most common complication after mandibular fracture repair, with an incidence ranging from 0.4 to 32%.

Question 36

Management of infection after mandibular repair

Answer 36

Management of these infections requires adequate incision and drainage as well as intravenous antibiotics and mouth care. If the source of infection is an exposed infected tooth root, it should be removed. It is important that rigid internal fixation be maintained until the bone fracture segments have ossified because nonrigid fixation, such as external fixation ormaxillomandibular fixation, can lead to worsening of infection. Removal of the internal hardware is rarely necessary unless the hardware is actively infected and loosened because of bone involvement (osteomyelitis)

Question 37

``` An 83-year-old man undergoes radiation therapy and surgical resection and coverage with a cranial bone graft to treat meningioma. The graft becomes infected and is removed 6 weeks after the procedure. One year later, the patient is scheduled to undergo reconstruction of the resulting 23-cm2 defect in the skull. Which of the following is a relative contraindication for the subsequent use of hydroxyapatite in this patient? A ) Age of patient B ) History of infection C ) History of radiation D ) Location of defect E ) Size of defect ```

Answer 37

C ) History of radiation Hydroxyapatite cement is widely used in cranioplasty. In one study, the complication rate of the use of hydroxyapatite in patients who have received irradiation to the scalp was 100%. Therefore, its use is not recommended in this population.

Question 38

Hydroxyapatite and skull infection

Answer 38

Reduction in theincidence of infection has been shown when a period of 1 year has elapsed between the initial injury or infection and the reconstruction with hydroxyapatite. Use of hydroxyapatite in frontal areas causes twice the incidence of infection than in its use in all other areas.

Question 39

Maximum defect size for Hydroxyapatite skull repair

Answer 39

Hydroxyapatite is approved by the FDA for reconstruction of bony defects up to 25 cm2 in size.

Question 40

Contraindications to hydroxyapetite skull repair

Answer 40

History of radiation Large full thickness defects in pediatric patients < 1 year after infection > 25 cm^2 defect

Question 41

``` When reattaching the medial canthal ligaments during a transnasal canthal wiring procedure, which of the following is the most appropriate placement of the drill holes with respect to the lacrimal fossa? A ) Anterior and inferior B ) Anterior and posterior C ) Posterior and inferior D ) Posterior and superior ```

Answer 41

D ) Posterior and superior When treating congenital and traumatic deformities of the naso-orbital-ethmoid region, reconstruction and reattachment of the medial canthal tendons are often necessary. Overcorrection with this procedure is essentially impossible, and every effort should be made to prevent relapse and recurrent telecanthus. To this end, the transnasal wires containing the medial canthus should be placed through drill holes positioned posterior and superiorto the posterior crest of the bony lacrimal fossa.

Question 42

Drill hole placement when reattaching the medial canthal ligaments during a transnasal canthal wiring procedure

Answer 42

Posterior and superior. | Overcorrection is virtually impossible.

Question 43

A 17-year-old girl is brought to the emergency department after she was hit in the left eye with a batted softball. Physical examination shows increased intraorbital pressure and decreasing visual acuity. Review of the CT scan confirms fracture of the orbital floor. Which of the following is the most appropriate immediate management? A ) Administration of mannitol followed by exploration of the orbital floor B ) Anticoagulation C ) Exploration of the orbital floor and repair with a bone graft D ) Exploration of the orbital floor and repair with synthetic material E ) Lateral canthotomy and cantholysis

Answer 43

E ) Lateral canthotomy and cantholysis Immediate lateral canthotomy and cantholysis are the most appropriate management of the condition described. Retrobulbar hematoma or orbital hemorrhage can follow either a direct injury to the orbital contents or a fracture that involves surrounding bones. Symptoms and signs include pain, reducing visual acuity, history of trauma, periorbital/lid hematoma, chemosis, proptosis, raised intraocular pressure, and ophthalmoplegia. A delayed repair of the orbital fracture, generally within one week of the trauma, is performed if necessary.Medical treatment of raised intraorbital pressure with mannitol or dexamethasone should be regarded as an adjunct to surgery. The first line of treatment is surgical, and lateral canthotomy at the bedside is the most effective immediate treatment for increased intraorbital pressure

Question 44

Therapeutic window before permanent damage from retrobulbar hematoma

Answer 44

There is a narrow therapeutic interval of 90 minutes before permanent damage to vision may occur.

Question 45

A 33-year-old man is brought to the emergency department after sustaining injuries to the face during a snowmobile collision. (Axial CT scan is shown: A comminuted fracture of the frontal sinus is shown in the CT scan, with significant displacement of fragments involving both the anterior and posterior frontal sinus walls and the region of the nasofrontal duct.) Which of the following is the most appropriate management? A ) Ablation of the frontal sinus B ) Cranialization and reconstruction of the anterior frontal sinus wall C ) Obliteration of the frontal sinus D ) Observation with x-ray studies monthly E ) Reconstruction of the nasofrontal duct and anterior and posterior frontal sinus walls

Answer 45

B ) Cranialization and reconstruction of the anterior frontal sinus wall A comminuted fracture of the frontal sinus is shown in the CT scan, with significant displacement of fragments involving both the anterior and posterior frontal sinus walls and the region of the nasofrontal duct. The most appropriate treatment is cranialization and reconstruction of the anterior wall to restore normal forehead contour and protect the brain. Reconstruction involves preserving sinus mucosa and reducing fractures of the nasofrontal duct and sinus walls. There are currently no data to support this technique, and in the patient described it could to lead to mucocele development as the nasofrontal duct became scarred and obstructed postoperatively

Question 46

Procedure for cranialization of the frontal sinus

Answer 46

Cranialization involves removing the posterior frontal sinus wall to make the sinus part of the intracranial space and blocking the nasofrontal duct, typically with bone or a pericranial flap so that sinus mucosa is excluded from the intracranial space. The anterior frontal sinus wall is also reconstructed as part of this procedure to restore normal forehead contour and to protect the brain.

Question 47

Procedure for ablation of the frontal sinus

Answer 47

Ablation (or exenteration) involves removing the anterior frontal sinus wall and allowing the skin to collapse in on the posterior wall, if it is intact, or on the dura if the posterior wall requires removal as well (as it would in this scenario). Ablation is appropriate only in extreme cases of acute infection that require open drainage and removal of infected bone.

Question 48

Procedure for obliteration of the frontal sinus

Answer 48

Obliteration of the frontal sinus involves removing the sinus mucosa and burring the bony walls to remove mucosal invaginations, plugging the nasofrontal duct, and filling the sinus cavity with fat, muscle, bone, or alloplasts.

Question 49

When is observation appropriate for frontal sinus fracture?

Answer 49

Observation is appropriate for minimally or nondisplaced fractures of the frontal sinus that do not involve the nasofrontal duct or do not acutely obstruct the nasofrontal duct. Regular plain x-ray studies should be obtained for several months afterward to monitor for development of a frontal sinus mucocele, which requires surgical treatment.

Question 50

A 41-year-old man was punched in the eye two days ago and now has numbness in his cheek and double vision. Physical examination shows paresthesias in the V2 distribution, edema of the eyelids, and proptosis. Diplopia occurs at 40 degrees of upward gaze, but there are no definite signs of entrapment. A coronal CT is shown (~75% of the floor). Which of the following is the absolute indication for repair of the orbital floor fracture in this patient? A ) Diplopia on upward gaze B ) Extent of orbital floor loss C ) Medial maxillary sinus wall fracture D ) Medial orbital wall fracture E ) Paresthesia between the lower eyelid and upper lip

Answer 50

B ) Extent of orbital floor loss The absolute indication for repair of the orbital floor fracture in the patient described is the CT finding of loss of greater than 50% of the orbital floor. Without repair, this patient is prone to enophthalmos and long-term diplopia.

Question 51

When is diplopia / extra ocular eye movement disturbance an indication for orbital floor fracture repair

Answer 51

Diplopia, without evidence of entrapment, is not an absolute indication for operative repairof orbital floor fractures, especially when not within 20 to 30 degrees of primary gaze. Diplopia in extreme gazes is not particularly dysfunctional; therefore, it is only a relative indication for surgery. Definite entrapment noted on examination would be an indication for surgery.

Question 52

Operative repair should be performed when an orbital floor fracture is at what %?

Answer 52

>50%

Question 53

Injury of the infraorbital nerve in orbital floor fractures

Answer 53

Numbness between the lower eyelid and upper lip indicates injury to the infraorbital nerve, which is present in nearly all orbital floor fractures. It is usually a neurapraxic injury, which improves to some degree with time.

Question 54

``` A 20-year-old man is undergoing open reduction and internal fixation of a nasoorbital-ethmoid fracture. Reconstruction of the medial canthal attachments using a transnasal approach is required. Which of the following best describes the correct placement of drill holes with respect to the posterior lacrimal crest during transnasal wiring? A ) Anteroinferior B ) Anterosuperior C ) Posteroinferior D )Posterosuperior ```

Answer 54

D )Posterosuperior

Question 55

Why overcorrect when performing transversal wiring of the medial cants after an NOE fracture?

Answer 55

The drill holes for the transnasal wires attached to the medial canthal ligaments are placed 1 to 2 mm above and behind the lacrimal fossa or posterior and superior to the posterior lacrimal crest. Clinical confirmation of slight overcorrection is warranted because relapse is common, and telecanthus is a likely postoperative occurrence despite attempts at overcorrection.

Question 56

``` A 42-year-old man comes to the office for consultation regarding the appearance of the right eye 10 months after sustaining a fracture of the right orbitozygomatic complex and multiple lacerations in a motor vehicle collision. He was unable to undergo treatment of the fractures because of other injuries. A photograph is shown. Which of the following is the most likely cause of the enophthalmos? A ) Atrophy of globe fat B ) Cicatrix of adnexal tissue C ) Eyelid lacerations D ) Increased orbital volume ```

Answer 56

D ) Increased orbital volume

Question 57

Posttraumatic enophthalmos is primarily the result of:

Answer 57

Posttraumatic enophthalmos is primarily the result of increased bony orbital volume. Atrophy of globe fat and cicatrix of adnexal tissue may also contribute to enophthalmos, but minimally. Posttraumatic enophthalmos results from displaced zygoma fractures, medial wall or floor blow-out fractures, and nasoorbito-ethmoidal fractures with disruption of the medial wall resulting in increased orbital volume.

Question 58

Enophthalmos is best assessed via:

Answer 58

Enophthalmos is best assessed on submental view to evaluate globe projection.

Question 59

A 43-year-old woman has periodic drainage of clear fluid from the nose three months after she sustained severe trauma to the face during a motor vehicle collision. She is concerned that the drainage may be cerebrospinal fluid. Which of the following tests of nasal secretions in this patient is most specific for leakage of cerebrospinal fluid? A ) Determination of protein content B ) Double halo sign C ) Glucose dipstick D ) Measurement of beta-2 transferrin level E ) Measurement of potassium level

Answer 59

D ) Measurement of beta-2 transferrin level Although decreased protein and potassium levels are associated with CSF leakage, these tests are not as specific for CSF. The test for double halo sign (fluid placement on a gauze pad or filter paper and observation for double halo formation) has a sensitivity of 78% but a false positive rate of 75%. Glucose dipstick testing was the first technique used to detect CSF. It is based on the principle that the glucose content of CSF exceeds that of mucus or blood.

Question 60

A 24-year-old woman is brought to the emergency department after being involved in a motor vehicle collision. Physical examination shows multiple minor abrasions of the face. Clear rhinorrhea is noted. CT of the head shows a nondisplaced fracture of the posterior table of the frontal sinus. No other serious injuries are noted. Thepatient is admitted to the hospital, and antibiotic therapy is initiated. Which of the following is the most appropriate next step in management? (A)Bed rest, head elevation, and observation (B)Cranialization of the frontal sinus (C)Craniotomy and repair of the dural tear (D)Lumbar puncture and drainage of spinal fluid (E)Obliteration of the frontal sinus

Answer 60

(A)Bed rest, head elevation, and observation The patient described has a nondisplaced fracture of the posterior table of the frontal sinus with a cerebrospinal fluid (CSF) leak and should be treated with antibiotic coverage and maneuvers to facilitate spontaneous resolution of the leak. These include bed rest and head elevation greater than 30 degrees. If the CSF leak persists for more than four days, spinal drainage is recommended. Prolonged CSF leakage for longer than seven to 10 days requires craniotomy, repair of the dural laceration, and either obliteration of the sinus or cranialization.

Question 61

Initial management for frontal sinus fracture with CSF leak

Answer 61

A nondisplaced fracture of the posterior table of the frontal sinus with a cerebrospinal fluid (CSF) leak should be treated with antibiotic coverage and maneuvers to facilitate spontaneous resolution of the leak. These include bed rest and head elevation greater than 30 degrees.

Question 62

If the CSF leak persists for more than ________, spinal drainage is recommended.

Answer 62

If the CSF leak persists for more than four days, spinal drainage is recommended.

Question 63

CSF leakage for __________ requires craniotomy, repair of the dural laceration, and either obliteration of the sinus or cranialization.

Answer 63

CSF leakage for longer than seven to 10 days requires craniotomy, repair of the dural laceration, and either obliteration of the sinus or cranialization.

Question 64

Treatment of isolated anterior frontal sinus fracture w/o depression

Answer 64

No required surgical treatment

Question 65

Treatment of isolated depressed anterior frontal sinus fracture

Answer 65

Surgical correction to restore aesthetic contour

Question 66

Treatment of isolated anterior frontal sinus fracture with frontonasal duct injury

Answer 66

Removal of sinus mucosa with obliteration of the sinus.

Question 67

Treatment of posterior frontal sinus fracture w/o displacement, CSF leakage or frontonasal duct involvement

Answer 67

Antibiotic treatment only

Question 68

Treatment of posterior frontal sinus fracture w/o displacement, but with CSF leakage

Answer 68

Initially treat conservatively with antibiotics only. Should the leakage persist for longer than 10 days despite measures to resolve spontaneously, a craniotomy with dural repair is required. This procedure is usually done in conjunction with neurosurgical colleagues.

Question 69

Treatment of posterior frontal sinus fracture w/ displacement,

Answer 69

Displaced posterior wall fractures require exploration with repair of any dural tears and either sinus obliteration or cranialization. Cranialization involves removal of the entire posterior table, plugging of the frontonasal duct, repair of any dural lacerations, and separation of the intracranial cavity from the aerodigestive tract. The frontal lobe is then expected to fall into and fill the previous sinus cavity.

Question 70

``` A 12-year-old boy is brought to the emergency department because of double vision six hours after sustaining a blow to the eye with an elbow while jumping on a trampoline. He has had pain since the incident but has not had loss of consciousness. He had one episode of nausea and vomiting before arrival. Pulse rate is 45 bpm, respirations are 18/min, and blood pressure is 110/80 mmHg. Examination shows photophobia, periorbital ecchymosis, and restriction of extraocular motion. CT of the head shows a fracture of the orbital floor. Which of the following is the most appropriate time for surgical repair of the fracture? (A)Emergently (B)1 to 3 Days (C)4 to 7 Days (D)8 to 14 Day ```

Answer 70

(A)Emergently Observation alone is not indicated for entrapment with nausea, vomiting, and oculocardiac reflex. Recent publications in the ophthalmologic literature emphasize the importance of urgent surgical intervention to prevent ocular muscle damage, improve postoperative function, and decrease the need for additional surgery.

Question 71

``` A 42-year-old man is brought to the emergency department 30 minutes after sustaining trauma to the face in a motor vehicle collision. Physical examination shows periorbital ecchymoses on the right, malar flattening, and enophthalmos. Neurologic examination shows numbness on the upper right lip. Radiographs show a displaced zygomaticomaxillary complex fracture. Anatomic reduction of each of the following is required in this patient EXCEPT (A)greater wing of the sphenoid (B)inferior orbital rim (C)nasomaxillary buttress (D)zygomaticofrontal suture (E)zygomaticomaxillary buttress ```

Answer 71

(C)nasomaxillary buttress Reduction of the nasomaxillary buttress is not typically involved inthis type of fracture pattern.

Question 72

Approximately ______% of patients with orbital fractures develop enophthalmos because of increased bony intraorbital volume. This is most frequently associated with __________________.

Answer 72

Approximately 15% to 22% of patients with orbital fractures develop enophthalmos because of increased bony intraorbital volume. This is most frequently associated with a zygomaticomaxillary complex fracture that has not been reduced adequately.

Question 73

Reduction of which fractures is important in fixing a ZMC fracture

Answer 73

- Appropriate reduction of the ZMC complex - Appropriate anatomic reduction of the greater wing of the sphenoid and lateral wall of the orbit is obtained after reduction the ZMC - - Correct reduction of the inferior orbital rim, zygomaticofrontal suture, and zygomaticomaxillary buttress is also important

Question 74

``` Which of the following fractures of the facial bones is most common during childhood? (A)Frontal sinus (B)Le Fort (C)Nasal (D)Orbital ```

Answer 74

(C)Nasal

Question 75

Most common facial fractures in pediatric patients

Answer 75

``` Mandible fractures (32-65%) Nasal fractures (12-45%) Orbital fractures (14-16%) Le Fort fractures (2-8%) Frontal sinus fractures - rare, except in teenage years when pneumatization of the sinus is approaching its completion. ```

Question 76

A 12-year-old girl is brought to the emergency department after she sustained injuries in a motor vehicle collision. Physical examination shows extensive lacerations of the right medial orbit and forehead (shown) with complete transection of the medial canthal tendon (MCT). For effective reattachment of the MCT with transnasal wiring, which of the following is the most appropriate direction of resuspension of the tendon in relation to the anterior lacrimal crest? (A)Anterior and inferior (B)Anterior and superior (C)Directly horizontal (D)Posterior and inferior (E)Posteriorand superior

Answer 76

(E)Posteriorand superior

Question 77

Anatomy of the medial canthal tendon

Answer 77

The medial canthal tendon (MCT) consists of three limbs: 1) a prominent anterior limb that inserts medially on the anterior lacrimal crest 2) a thinner posterior limb that attaches to the posterior lacrimal crest 3) a vertical limb of fascia that inserts on the medial orbital rim inferior to the nasal frontal suture.

Question 78

A 70-year-old woman is brought to the emergency department after a fall. Examination shows periocular ecchymosis, epistaxis, and a bluish bulge of the septal mucosa. No other serious injuries are noted. CT shows fracture of the nasal septum. Which of the following is the most appropriate next step in management? (A)Administration of intranasal oxymetazoline (Afrin) (B)Drainage of hematomas and resection of septal cartilage (C)Evacuation of hematomas through a direct incision (D)Nasal packing only (E)Needle aspiration of hematomas

Answer 78

(C)Evacuation of hematomas through a direct incision

Question 79

Treatment of septal hematoma after trauma

Answer 79

Evacuation through a direct incision

Question 80

Procedure for evacuation of a septal hematoma

Answer 80

Septal hematomas should be treated promptly with an L-shaped incision over the hematoma with thorough evacuation using suction and irrigation. This can be followed by loose repair of the incision to allow drainage and quilting sutures to prevent reaccumulation. It should be followed by internal nasal packing, systemic antibiotic coverage, and close follow-up to ensure absence of reaccumulation. Generally, although septal hematomas tend to be bilateral, they should not be incised on both sides because through-and-through septal perforation may occur. If the entire hematoma cannot be evacuated with a unilateral approach, the incisions on each side should be made at different levels.

Question 81

Why not resect septal cartilage at time of drainage of septal hematoma?

Answer 81

Resection of septal cartilage at the time of drainage should be avoided because septal perforation may occur.

Question 82

``` A 30-year-old woman sustains a nasoethmoid fracture in a motor vehicle collision. Radiographs of the fracture site show extensive fracture comminution that extends into the point of insertion of the medial canthal tendon. Transnasal medial canthopexies are to be performed for fracture fixation. The classification of this fracture is Markowitz and Manson type 3. Which of the following is the most appropriate management? (A)External nasal splint fixation (B)Kirschner wire fixation (C)Rigid plate fixation (D)Transnasal wiring ```

Answer 82

(D)Transnasal wiring

Question 83

The Markowitz and Manson system

Answer 83

Used to classify nasoethmoid fractures according to the status of the bone fragment into which the medial canthal tendon inserts

Question 84

The Markowitz and Manson system : Type 1 fracture

Answer 84

NOE Fracture: In a type 1 fracture, there is a large central fragment. The fragment can be reduced and a plate can be applied to stabilize the nasoethmoid region.

Question 85

The Markowitz and Manson system : Type 2 fracture

Answer 85

Type 2 fractures exhibit comminution of the central fragment, but the point of insertion of the medial canthal tendon remains intact.

Question 86

The Markowitz and Manson system : Type 3 fracture

Answer 86

Patients with type 3 fractures have extensive comminution of the segmentthat extends into the point of tendon insertion. Because stabilization with a plate is not possible due to the lack of bone, transnasal canthopexy is typically required to stabilize the medial canthal tendon.

Question 87

``` A 24-year-old man is brought to the emergency department one hour after he sustained injuries to the face and head in a motor vehicle collision. Physical examination shows a 5 × 1.5-cm laceration of the forehead, ecchymosis over the glabellar region, and watery nasal discharge. CT of the head shows a fracture of the frontal sinus. Which of the following findings on analysis of the nasal discharge confirms cerebrospinal rhinorrhea? (A)Alpha fetoprotein (B)Beta-2 transferrin (C)Glucose (D)Halo sign (E)Potassium ```

Answer 87

(B)Beta-2 transferrin

Question 88

A 37-year-old woman is brought to the emergency department two hours after she sustained injuries to the face in a motor vehicle collision. Radiographs show an orbital zygomatic fracture on the left side. On ophthalmologic examination, the left pupil fails to constrict when direct light is shined in the eye; consensual pupillary constriction is normal. Color perception is diminished in the left eye. Findings in the right eye are normal. Which of the following is the most likely cause of these findings? (A)Detachment of the retina (B)Extension of the fracture through the optic canal (C)Impingement of bone fragments on the optic (II) nerve (D)Shear force injury to theoptic (II) nerve (E)Thrombosis of the retinal artery

Answer 88

(D)Shear force injury to theoptic (II) nerve

Question 89

Percent of patients w/ optic neuropathy after severe facial trauma

Answer 89

The finding of traumatic optic neuropathy has been reported in 2% to 5% of patients with severe facial trauma.

Question 90

Where does shear force to the optic nerve happen

Answer 90

The dural sheath is firmly attached to the optic nerve at its entrance into the optic foramen. Rapid deceleration injuries of the head can generate forces that are concentrated at the optic foramen.

Question 91

A 38-year-old man sustains panfacial fractures in a motor vehicle collision. During surgical reduction, which of the following structures is most appropriate to restore the transverse dimension of the facial skeleton? (A)Condyle and posterior mandibular ramus (B)Mandibular arch (C)Nasomaxillary buttress (D)Pterygomaxillary buttress (E)Zygomaticomaxillary buttress

Answer 91

(B)Mandibular arch

Question 92

Vertical buttresses

Answer 92

Nasomaxillary Zygomaticomaxillary Pterygomaxillary The condyle and posterior mandibular ramus make up yet another buttress establishing posterior facial height.

Question 93

Horizontal buttresses

Answer 93

Frontal Zygomatic Maxillary Mandibular

Question 94

What is the mandibular buttress composed of?

Answer 94

The mandibular arch

Question 95

``` A 25-year-old man is brought to the emergency department 30 minutes after sustaining severe trauma to the head and face during a motor vehicle collision. Examination shows clear-fluid rhinorrhea, indicating leakage of cerebrospinal fluid. This patient has most likely sustained an injury to which ofthe following structures? (A)Anterior ethmoidal air cells (B)Cribriform plate (C)Frontonasal duct (D)Orbital portion of frontal bone (E)Superior nasal concha ```

Answer 95

(B)Cribriform plate

Question 96

What is the cribriform plate comprised of?

Answer 96

The horizontal component of the ethmoid bone

Question 97

Lateral masses of the ethmoid bone

Answer 97

he lateral masses of the ethmoid bone extend from the periphery of the cribriform plate, contain the anterior ethmoid air cells, and articulate with the orbital portion of the frontal bone

Question 98

Crista galli

Answer 98

The crista galli is a midline prominence that serves as a point of attachment for intracranial soft tissue and that centers the cribriform plate.

Question 99

``` A 20-year-old man who sustained a naso-orbital-ethmoid fracture undergoes transnasal wire canthopexy. Which of the following vectors, relative to the position of the insertion of the medial canthal tendon, is most appropriate for placement of the primary wire? (A)Anterior and inferior (B)Anterior and superior (C)Posterior and inferior (D)Posterior and superior ```

Answer 99

(D)Posterior and superior

Question 100

The bony intercanthal distance should be:

Answer 100

The bony intercanthal distance should be between 16 and 23 mm

Question 101

``` The 27-year-old woman shown above comes to the office for evaluation because she has had diplopia for the past 18 months. Physical examination shows orbital dystopia, enophthalmos, and malar flattening on the right. On the basis of the current findings, this patient’s prior injury was most likely which of the following fractures? (A)Le Fort II fracture (B)Le Fort III fracture (C)Orbital floor blow-out fracture (D)Orbital roof fracture (E)Orbitozygomatic complex fracture ```

Answer 101

(E)Orbitozygomatic complex fracture Orbital floor or roof fractures would not result in malar flattening. Le Fort II and III fractures would cause a malocclusion, which is not present in this patient.

Question 102

Clinical features typical for orbitozygomatic fractures

Answer 102

The clinical findings of orbital dystopia, enophthalmos, and malar flattening on the patient’s right side are typical for orbitozygomatic fractures. With the downward pull of the muscles, the zygoma rotates and the orbital volume is increased. This results in enophthalmos and possible dystopia, depending on the degree of displacement.

Question 103

A 7-year-old boy is brought to the emergency department after sustaining trauma to the face. He has nausea and vomiting but is alert and oriented to time and place. Pulse rate is 48/min. Physical examination shows right periorbital ecchymosis, diplopia, and limited vertical gaze. Visual acuity is within normal limits. Which of the following is the most likely finding on CT scan of the head and craniofacial skeleton? (A)Compression of the optic nerve (B)Displaced fracture of the zygoma (C)Large (greater than 3 cm) displaced fracture of the orbital floor (D)Minimally displaced fracture of the orbital floor

Answer 103

(D)Minimally displaced fracture of the orbital floor Based on the patient’s age, signs, and symptoms, a CT scan is most likely to show a minimally displaced fracture of the orbital floor, suggesting a trapdoor fracture of the orbital floor. A CT scan is not likely to show compression of the optic nerve because the patient does not have a relative afferent pupillary defect. A CT scan also is unlikely to show a displaced fracture of the zygoma because this type of fracture usually occurs in older patients. This study should not disclose a large displaced fracture of the orbital floor because this type of fracture does not typically cause oculocardiac reflex. Because the patient’s mental status is intact, a CT scan is not likely to show a subarachnoid hemorrhage.

Question 104

Trapdoor orbital floor fracture on DT

Answer 104

A CT scan is most likely to show a minimally displaced fracture of the orbital floor. This type of fracture allows herniation of the orbital contents, which are then entrapped.

Question 105

In which patient population do trapdoor fractures most often occur?

Answer 105

These most commonly occur in children, possibly because of the relative elasticity of their bones, which allows them to snap back into position after tissue herniates through the fracture.

Question 106

Oculocardiac reflex

Answer 106

A trapdoor fracture of the orbital floor can cause an oculocardiac reflex, which produces bradycardia, nausea, and syncope.

Question 107

``` A 25-year-old man comes to the office because he has numbness of the tip of the nose six weeks after he sustained a naso-orbital-ethmoid fracture during a motor vehicle collision. The most likely cause of the numbness is damage to which of the following nerves? (A)Anterior ethmoidal (B)Infraorbital (C)Infratrochlear (D)Nasopalatine (E)Pterygopalatine ```

Answer 107

(A)Anterior ethmoidal

Question 108

What nerve innervates the nasal tip?

Answer 108

The anterior ethmoidal nerve

Question 109

What nerve supplies the upper and middle turbinates?

Answer 109

The lateral branch of the pterygopalatine nerve

Question 110

What nerve innervates the septum?

Answer 110

The medial branch of the pterygopalatine nerve

Question 111

What does the nasopalatine nerve innervate?

Answer 111

The nasopalatine nerve, which is the terminal branch of the pterygopalatine nerve, innervates the maxillary incisor teeth, gingiva, and palate

Question 112

What is the terminal branch of the pterygopalatine nerve?

Answer 112

The nasopalatine nerve

Question 113

``` In a patient with fracture of the frontal sinus, laboratory analysis of which of the following is most reliable to confirm cerebrospinal rhinorrhea? (A)Albumin (B)Beta-2 transferrin (C)Glucose (D)Glutamine (E)Lactic acid ```

Answer 113

(B)Beta-2 transferrin

Question 114

Sensitivity / specificity of beta-2 transferrin

Answer 114

Sensitivity near 100% and a specificity near 95%

Question 115

Cranialization is indicated for patients with which of the following conditions of the frontal sinus? (A)Fracture of the anterior sinus wall (B)Fracture of the nasofrontal duct (C)Fracture of the posterior sinus wall (D)Fracture of the sinus floor into orbital roof (E)Post-traumatic frontal sinus mucocele

Answer 115

(C)Fracture of the posterior sinus wall Although cranialization is indicated for fractures of the posterior sinus wall, not all frontal sinus fractures involving the posterior wall require cranialization. Exceptions would be noted in cases of undisplaced fracture in which the dura is deemed intact by clinical observation and confirmatory testing. Even in patients with leakage of cerebrospinal fluid (CSF), many surgeons will allow up to 10 days for the CSF leak to resolve on its own before resorting to cranialization, as long as all fractures are undisplaced and the nasofrontal duct is patent. In addition, cases of posterior wallfracture with obstructed nasofrontal ducts can be addressed with sinus obliteration and not cranialization, as long as there is no brain injury and little or no comminution of the posterior wall.

Question 116

What posterior frontal sinus fractures don't require cranialization?

Answer 116

Undisplaced fracture where the dura is deemed intact by clinical observation and confirmatory testing. Even in patients with leakage of cerebrospinal fluid (CSF), many surgeons will allow up to 10 days for the CSF leak to resolve on its own before resorting to cranialization, as long as all fractures are undisplaced and the nasofrontal duct is patent.

Question 117

Posterior wall frontal sinus fracture (no comminution) with obstructed nasofrontal ducts - treatment

Answer 117

Cases of posterior wall fracture with obstructed nasofrontal ducts can be addressed with sinus obliteration and not cranialization, as long as there is no brain injury and little or no comminution of the posterior wall.

Question 118

How to determine source of CSF leak if it is not completely obvious

Answer 118

If there are other potential sources of a CSF leak, sortingout the cause can be done preoperatively with a metrizamide CT scan.

Question 119

Management of an anterior table fracture with an intact posterior table and an intact frontonasal duct

Answer 119

Management of an anterior table fracture with an intact posterior table and an intact frontonasal duct should be addressed by plating the anterior table to restore forehead contour.

Question 120

Frontal sinus fracture with obstruction of the nasofrontal duct: treatment

Answer 120

If the nasofrontal duct is obstructed, then obliteration of the frontal sinus is indicated.

Question 121

Frontal sinus floor fracture medial to the supraorbital foramen

Answer 121

When the sinus floor is fractured medial to the supraorbital foramen, there is a good chance that the nasofrontal duct is injured, in which case sinus obliteration is indicated. If it is not injured, then plating is indicated to restore the orbital roof if fracture lines are displaced.

Question 122

Management of post-traumatic frontal sinus mucocele

Answer 122

Post-traumatic mucoceles of the frontal sinus are managed by sinus obliteration. The exception is,however, that cranialization could be indicated in a few instances where the mucocele has become extremely expanded and destructive on the posterior table.

Question 123

``` A 7-year-old boy is being evaluated after sustaining facial injuries when he fell while climbing playground equipment. Radiographs show a fracture of the orbit. Which of the following additional findings best supports urgent surgical repair in this patient? (A) Acute enophthalmos (B) Corneal abrasion (C) Diplopia on upward gaze (D) Entrapment of the rectus muscle (E) Hyphema ```

Answer 123

(D) Entrapment of the rectus muscle

Question 124

Timing for repair of an orbital fracture

Answer 124

Most orbital fractures can be safely and effectively repaired. within two weeks. This allows periorbital edema to resolve and makes the dissection easier. In the pediatric population, there is a subset of orbital fractures which require emergent repair: A trapdoor fracture refers to an orbital floor fracture that, because of the elastic recoil of cartilaginous bone, traps orbital contents and the inferior rectus muscle within the maxillary sinus.

Question 125

Indication for repair of orbital floor fractures that are non-emergent

Answer 125

Indications for repairing orbital fractures include persistent diplopia in central gaze, early enophthalmos or vertical dystopia, and large fracture size, which may predispose later development of enophthalmos. Such fractures are repaired with some urgency within two weeks of the injury.

Question 126

CT scan of trapdoor orbital fracture

Answer 126

Often, the recoiled floor appears uninjured. CT scan, however, will demonstrate the incarcerated muscle.

Question 127

Ocular injury vs orbital fracture

Answer 127

Ocular injury is a contraindication to early surgical intervention. Orbital manipulation increases the risksof secondary bleed into the anterior chamber and the development of acute closed-angle glaucoma.

Question 128

``` A 1-month-old infant is brought to the office by her parents for evaluation of a skull deformity. The CT scan demonstrates an infant with a narrowed forehead and decreased bitemporal distance. There is also evidence of orbital hypotelorism and an obliterated or fused metopic suture. Which of the following cranial dysmorphologies is the most likely diagnosis? (A) Dolichocephaly (B) Plagiocephaly (C) Scaphocephaly (D) Trigonocephaly (E) Turricephaly ```

Answer 128

(D) Trigonocephaly

Question 129

Trigonocephaly

Answer 129

Premature fusion of the metopic suture leading to a triangular shaped forehead: narrowed forehead and decreased bitemporal distance. There is also evidence of orbital hypotelorism.

Question 130

Metopic suture

Answer 130

Divides the two halves of the frontal bone.

Question 131

Premature fusion of the metopic suture results in:

Answer 131

Trigonocephaly

Question 132

Trigonocephaly result from

Answer 132

Premature fusion of the metopic suture

Question 133

Scaphocephaly

Answer 133

Scaphocephaly is a cranial shape excessive in the anterior-posterior dimension and narrow in the bitemporal dimension. This results in a long and narrow (boat-like) shape of the head. This results from premature fusion of the sagittal suture.

Question 134

Premature fusion of the sagittal suture results in

Answer 134

Scaphocephaly

Question 135

Dolichocephaly

Answer 135

Scaphocephaly

Question 136

Another name for scaphocephaly

Answer 136

Dolichocephaly

Question 137

Plagiocephaly

Answer 137

Plagiocephaly or “twisted head” is used to describe anterior or posterior deformities. Plagiocephaly is classified as anterior or posterior as well as synostotic and nonsynostotic or deformational.

Question 138

Anterior synostotic plagiocephaly

Answer 138

Coronal craniosynostosis

Question 139

Posterior synostotic plagiocephaly

Answer 139

Lambdoid craniosynostosis

Question 140

Coronal craniosynostosis

Answer 140

Anterior synostotic plagiocephaly

Question 141

Lambdoid craniosynostosis

Answer 141

Posterior synostotic plagiocephaly

Question 142

Nonsynostotic plagiocephaly

Answer 142

Anterior or posterior nonsynostotic plagiocephaly refers to deformational plagiocephaly or skull molding from a persistent sleep position.

Question 143

Turricephaly or oxycephaly

Answer 143

Turricephaly or oxycephaly is used to describe vertically tall head shapes that are usually associated with the brachycephaly (short in the anterior-posterior dimension) of bicoronal syndromic craniosynostosis.

Question 144

Brachycephaly

Answer 144

Short in the anterior-posterior dimension, associated with bicoronal syndromic craniosynostosis.

Question 145

A 36-year-old man has fever and headache six months after sustaining a frontal sinus fracture involving the frontonasal duct in a motor vehicle collision. At the time of injury, he underwent open reduction and internal fixation of the anterior wall of the sinus using microplates and obliteration of the sinus with fat grafts. Current CT scan shows a mucocele. Which of the following is the most likely cause of this finding? (A) Fat necrosis (B) Hardware failure (C) Osteomyelitis (D) Retained sinus mucosa (E) Undiagnosed fracture of the posterior wall

Answer 145

(D) Retained sinus mucosa

Question 146

When do mucoceles of the frontal sinus typically occur?

Answer 146

They typically occur in patients with untreated fractures of the frontal sinus. Mucoceles can also develop if all of the mucosal lining is not removed during obliteration of the sinus.

Question 147

Mucocele vs mucopyocele

Answer 147

A mucocele is generally sterile and filled with secretions; if it becomes infected by bacteria, it is referred to as a mucopyocele.

Question 148

Preferred fill materials for sinus obliteration

Answer 148

Cancellous bone and vascularized soft-tissue flaps are the preferred fill materials for sinus obliteration procedures. Free fat and muscle grafts are associated with necrosis and potential resorption. Use of hydroxyapatite cement has produced results inferior to cancellous bone.

Question 149

``` A 31-year-old man undergoes open reduction and internal fixation of a naso-orbital-ethmoid fracture. During the procedure, avulsion of the right medial canthal tendon is noted. Which of the following is the most appropriate management? (A) No intervention is needed (B) Application of a long nasal splint (C) Transnasal canthopexy (D) Placement of a lacrimal stent (E) Dacryocystorhinostomy ```

Answer 149

(C) Transnasal canthopexy If the canthal tendon is partially detached, simple observation is likely to lead to complete detachment and telecanthus, which is difficult to treat postoperatively. Therefore, the most appropriate management of partial detachment of the medial canthal tendon is transnasal canthopexy with or without totally detaching the medial canthal tendon. Application of a long nasal splint is unlikely to keep the tendon adherent tothe frontal process of the maxilla. Lacrimal stenting or dacryocystorhinostomy may be indicated for other reasons such as lacrimal obstruction; however, this is not necessary for the management of a detached medial canthal tendon.

Question 150

Management of partial detachment of the medial canthal tendon

Answer 150

If the canthal tendon is partially detached, simple observation is likely to lead to complete detachment and telecanthus, which is difficult to treat postoperatively. Therefore, the most appropriate management of partial detachment of the medial canthal tendon is transnasal canthopexy with or without totally detaching the medial canthal tendon.

Question 151

Management of a NOE fracture with intact medial canthal tendon

Answer 151

If the bone fragment is free but the canthal tendon is intact, the bone fragment can be fixed using transnasal fixation such as a transnasal wire.

Question 152

What is the lateral orbital wall made up of?

Answer 152

The lateral orbital wall is made up of the ethmoid and palatine bones.

Question 153

Maxillary bone anatomy

Answer 153

The maxillary bone makes up the buttresses and walls of the maxillary sinus, a portion of the orbital floor, and the medial aspect of the inferior orbital rim.

Question 154

``` A 48-year-old man is brought to the emergency department one hour after he sustained injuries to the face in a motor vehicle collision. Radiographs show an orbital zygomatic fracture. Which of the following is the single most important landmark for proper alignment of this fracture? (A) Infraorbital rim (B) Zygomaticofrontal buttress (C) Zygomaticomaxillary buttress (D) Zygomaticosphenoid articulation (E) Zygomaticotemporal buttress ```

Answer 154

(D) Zygomaticosphenoid articulation

Question 155

Bones that comprise the orbit

Answer 155

``` Ethmoid Frontal Lacrimal Maxilla Palatine Greater and lesser wings of the sphenoid ```

Question 156

The sphenoid portion of the lateral orbit is separated from the roof of the orbit by _____________ and from the floor by _____________

Answer 156

The sphenoid portion of the lateral orbit is separated from the roof of the orbit by the superior orbital fissure and from the floor by the inferior orbital fissure

Question 157

A classic orbital zygomatic fracture requires a fracture through:

Answer 157

A classic orbital zygomatic fracture requires a fracture through the lateral orbital wall, which represents articulation of the zygoma with the greater wing of the sphenoid.

Question 158

``` A 40-year-old man has swelling of the face and bleeding from the nose after he was kicked by a horse. Physical examination shows fracture of the frontal sinus. CT scan of the head shows pneumocephalus and displacement of the anterior and posterior walls of the frontal sinus secondary to comminuted fractures of both sinuses. Which of the following is the most appropriate management? (A) Ablation of the frontal sinus (B) Cranialization of the frontal sinus (C) Enlargement of the frontonasal duct (D) Exenteration of the frontal sinus (E) Obliteration of the frontal sinus ```

Answer 158

(B) Cranialization of the frontal sinus

Question 159

When is cranialization of the frontal sinus appropriate?

Answer 159

Cranialization of the frontal sinus is the most appropriate management of a patient with significant displacement of both the anterior and posterior tables of the sinus. This procedure allows close inspection of the dura for possible tear as well as dealing with possible injury of the nasofrontal duct.

Question 160

A 12-year-old boy has significant malocclusion after sustaining facial injuries in a motor vehicle collision. A three-dimension CT scan shows a fracture of the condyle on the left and a displaced symphyseal fracture. Which of the following is the most appropriate management? (A) Maxillomandibular fixation for four weeks (B) Maxillomandibular fixation for 10 to 14 days (C) Open reduction and fixation of both fractures (D) Open reduction and fixation of the symphyseal fracture followed by maxillomandibular fixation for two weeks (E) Rest and initiation of a soft diet

Answer 160

(D) Open reduction and fixation of the symphyseal fracture followed by maxillomandibular fixation for two weeks In this child who has significant malocclusion resulting from fractures of the condyle and symphysis, the most appropriate management is open reduction and internal fixation of the symphyseal fracture, followed by a short course (10 to 14 days) of maxillomandibular fixation. Open reduction is the treatment of choice for symphyseal fractures. However, rigid fixation with metallic plates and screws remains controversial in children, and some surgeons advocate the removal of these plates and screws after the fracture has healed. Others recommend absorbable plates and screws combined with a short course of maxillomandibular fixation. When the maxillomandibular fixation is removed, active physical therapy should be initiated because children are at increased risk for development of ankylosis of the temporomandibular joint. Rest and initiation of a soft diet are inappropriate because of the risk for significant malocclusion. Instead, this course of treatment, combined with physical therapy, is recommended for children who have facial fractures not associated with malocclusion. Maxillomandibular fixation is not indicated for more than 10 to 14 days because of the speed of healing in young children and the risk for ankylosis occurring with prolonged immobilization, as mentioned above.

Question 161

Treatment of symphyseal fracture

Answer 161

Open reduction is the treatment of choice for symphyseal fractures

Question 162

Mixed dentition

Answer 162

The presence of both deciduous (primary) and permanent (secondary) teeth within the oral cavity simultaneously; it typically occurs between ages 8 and 10 years.

Question 163

Mandibular condyle in children

Answer 163

In children, the mandibular condyle is immature, highly vascular, and covered with a thin sheath of periosteum. It is commonly described as a “vascular sponge.” As a result, open reduction of pediatric condylar fractures is discouraged.

Question 164

Duration of Maxillomandibular fixation in children

Answer 164

Maxillomandibular fixation is not indicated for more than 10 to 14 days because of the speed of healing in young children and the risk for ankylosis occurring with prolonged immobilization.

Question 165

``` A 22-year-old woman comes to the office two months after sustaining injuries to the face during a motor vehicle collision. Because of other injuries, repair of the facial injuries was delayed. Physical examination shows enophthalmos and increased width of the midface. This patient most likely has which of the following facial fractures? (A) Le Fort I (B) Le Fort II (C) Le Fort III (D) Mandibular subcondylar (E) Zygomatic complex ```

Answer 165

(E) Zygomatic complex

Question 166

Main contributor to the width of the midface

Answer 166

Zygomatic arch

Question 167

What typically happens to facial dimensions when the zygoma is inadequately reduced?

Answer 167

If the zygoma is inadequately reduced, projection of the malar eminence typically decreases and facial width typically increases secondary to lateral displacement of the zygomatic arch.

Question 168

A 23-year-old man has ectropion and shortening of the lower lid of the left eye two months after undergoing repair of an isolated orbital floor blowout fracture with a cranial bone graft via a subtarsal approach. Physical examination shows 2 mm of scleral show and 1 mm of lagophthalmos. Examination of the eyes shows normal Bell phenomenon. Which of the following is the most appropriate initial management? (A) Kuhnt-Szymanowski procedure (B) Lateral canthoplasty (C) Massage of the lower lid (D) Nasal septal cartilage grafting (E) Release of scar tissue and application of a Frost traction suture

Answer 168

(C) Massage of the lower lid The initial management of ectropion and lower eyelid shortening is massage. This patient has minimal scleral show, lagophthalmos, and normal Bell phenomenon,which suggest minimal risk to the cornea. In many cases, scleral show and lagophthalmos improve spontaneously with maturation of scar tissue. Six months of conservative management should be allowed before surgical intervention is undertaken. If ectropion and lid shortening persist for more than six months after the original surgical procedure or if the cornea is at risk for desiccation and injury, surgical correction should be performed. Corrective options include Kuhnt-Szymanowski procedure (horizontal shortening of the lower lid), lateral canthoplasty, release of scar tissue and application of a Frost traction suture, and nasal septal cartilage grafting to support the posterior lamella.

Question 169

Lagophthalmos

Answer 169

Lagophthalmos is defined as the inability to close the eyelids completely

Question 170

Bell's phenomenon

Answer 170

Bell's phenomenon: upward and outward movement of the eye, when an attempt is made to close the eyes. Present in about 75% of the population

Question 171

Duration of conservative management for ectropion and lower lid shortening (postoperative or post traumatic)

Answer 171

Six months of conservative management should be allowed before surgical intervention is undertaken.

Question 172

Kuhnt-Szymanowski procedure

Answer 172

Horizontal shortening of the lower lid

Question 173

``` The firstborn child of a Caucasian couple with no abnormalities has bilateral cleft lip and palate. Which of the following percentages best represents the possibility that this couple's next child will have cleft lip, with or without cleft palate? (A) 2% (B) 4% (C) 8% (D) 16% (E) 32% ```

Answer 173

(C) 8%

Question 174

Risk of familial recurrence for cleft lip with or without cleft palate: 1 affected parent

Answer 174

3-5

Question 175

Risk of familial recurrence for cleft lip with or without cleft palate: 1 affected child

Answer 175

4

Question 176

Risk of familial recurrence for cleft lip with or without cleft palate: 2 affected children

Answer 176

9

Question 177

Risk of familial recurrence for cleft lip with or without cleft palate: affected parent and affected child

Answer 177

17

Question 178

Risk of familial recurrence for cleft lip with or without cleft palate: monozygotic twins

Answer 178

40-50

Question 179

Risk of familial recurrence for cleft lip with or without cleft palate: dizygotic twins

Answer 179

5

Question 180

A 26-year-old woman comes to the office for consultation one year after undergoing open reduction and internal fixation of a fracture of the left zygomaticomaxillary complex. During that procedure, a titanium plate was placed for reconstruction of the orbital floor defect. Examination shows enophthalmos and malar asymmetry. Which of the following is the most likely cause of enophthalmos in this patient? (A) Atrophy of the intraorbital fat contents (B) Fibrosis of the extra ocular muscles (C) Herniation of the orbital contents into the maxillary sinus (D) Inadequate reduction of the fracture (E) Inadequate resuspensionof the soft tissue of the cheek

Answer 180

(D) Inadequate reduction of the fracture The major cause of persistent enophthalmos after surgery is inadequate reduction of the fracture fragments. Atrophy of intraorbital fat, fibrosis of the extraocular muscles, and herniation of the orbital contents can also cause a mismatch between the volume of the orbit and its contents. However, these options do not account for the malar asymmetry. Fibrosis of the extraocular muscles can be ruled out by the forward traction and forced duction tests, which also rule out entrapment of the extraocular muscles.

Question 181

The major cause of persistent enophthalmos after surgery:

Answer 181

The major cause of persistent enophthalmos after surgery is inadequate reduction of the fracture fragments.

Question 182

Key to the reduction of a zygomaticomaxillary complex fracture:

Answer 182

The key to the reduction of a zygomaticomaxillary complex fracture is accurate reduction of the interface between the zygomatic and sphenoid bones.

Question 183

An 18-year-old woman sustains an isolated depressed fracture of the zygomatic arch when she is struck on the left cheek with a baseball. Fracture reduction is planned using the temporal (Gillies) approach. During this procedure, an elevating device should be inserted into which of the following tissue planes? (A) Between the skin and the superficial temporal fascia (B) Between the superficial temporal fascia and the deep temporal fascia (C) Between the deep temporal fascia and the temporalis muscle (D) Between the temporalis and lateral pterygoid muscles (E) Deep to the masseter muscle

Answer 183

(C) Between the deep temporal The temporal (Gillies) approach to reduction of a zygomatic arch fractureinvolves creating an incision in the temporal region and inserting an elevating device between the deep temporal fascia and the temporalis muscle. The strong layer of fascia attached to the upper border of the zygomatic arch guides the instrument into a position immediately beneath the malar eminence, allowing the surgeon to reposition the depressed fracture fragments both laterally and outward. If the elevating device is passed through the subcutaneous plane (between the skin and the superficial temporalfascia) or the plane between the superficial and deep temporal fascia, it will not descend to its desired position beneath the malar eminence and will instead be placed superficial to the zygomatic arch.The plane deep to the temporalis muscle leads intothe infratemporal fossa, which contains the lateral and medial pterygoid muscles, the maxillary artery, the pterygoid venous plexus, the mandibular branch of the trigeminal nerve (V3) and its derivatives, the chorda tympani, and the otic ganglion. The masseter muscle arises from the lower border and medial surface of the zygomatic arch and extends inferiorly to attach to the lateral aspect of the mandibular ramus. This muscle is not accessible through the temporal scalp.

Question 184

The temporal (Gillies) approach to reduction of a zygomatic arch fracture

Answer 184

The temporal (Gillies) approach to reduction of a zygomatic arch fracture involves creating an incision in the temporal region and inserting an elevating device between the deep temporal fascia and the temporalis muscle. The strong layer of fascia attached to the upper border of the zygomatic arch guides the instrument into a position immediately beneath the malar eminence, allowing the surgeon to reposition the depressed fracture fragments both laterally and outward.

Question 185

The plane deep to the temporalis muscle

Answer 185

The plane deep to the temporalis muscle leads into the infratemporal fossa, which contains the lateral and medial pterygoid muscles, the maxillary artery, the pterygoid venous plexus, the mandibular branch of the trigeminal nerve (V3) and its derivatives, the chorda tympani, and the otic ganglion.

Question 186

Anatomy of the masseter muscle

Answer 186

The masseter muscle arises from the lower border and medial surface of the zygomatic arch and extends inferiorly to attach to the lateral aspect of the mandibular ramus.

Question 187

``` A 28-year-old man is brought to the emergency department one hour after he sustained injuries to the face when he fell down a flight of stairs. Which of the following physical findings indicates that this patient does NOT have an isolated naso-orbital-ethmoid fracture? (A) Deep nasofrontal angle (B) Epiphora (C) Mobility of the maxilla (D) Telecanthus (E) Upturning of the nasal tip ```

Answer 187

(C) Mobility of the maxilla In a naso-orbital-ethmoid fracture, which involves the superiornose, canthal-bearing segments, and ethmoid sinuses, the maxilla remains stable because most of it is inferior to the fracture. A naso-orbital-ethmoid fracture has various physical findings. The depressed nasal segment creates a deep nasofrontal angle. Regional edema can temporarily occlude the puncta, leading to epiphora (tearing). The medial canthi, with or without the small canthal-bearing segments, can be detached, creating telecanthus (an increased distance between the medial canthi). Fracture of thesuperior half of the nose leads to upturning of the nasal tip

Question 188

Management of a 22-year-old woman who sustains a comminuted fracture of the posterior table of the frontal sinus

Answer 188

Cranialization of the frontal sinus

Question 189

Management of a 17-year-old boy who sustained a nondisplaced fracture of the frontal sinus has a cerebrospinal fluid leak

Answer 189

Observation for one week

Question 190

Management of a 43 yo man who, five years after sustaining a displaced fracture of the anterior table of the frontal sinus that was not treated operatively, has a mucocele

Answer 190

Obliteration of the frontal sinus

Question 191

When is cranialization of the frontal sinus indicated?

Answer 191

In patients who have comminuted fractures of the posterior table of the frontal sinus, rigid fixation cannot be achieved, and management involves cranialization, whereby the sinus is eliminated and thus converted to a portion of the intracranial cavity. This procedure requires neurosurgical exposure.

Question 192

Appropriate management for non displaced fracture of the posterior wall of the frontal sinus without CSF leak

Answer 192

No operative intervention is required for nondisplaced fractures of the posterior wall of the frontal sinus as long as there is no evidence of cerebrospinal fluid leak.

Question 193

Indication for obliteration of the frontal sinus

Answer 193

Mucocele is a rare, late complication of untreated frontal sinus injury. Symptoms include headache and frontal sinus and orbital pain. Because mucoceles can erode the bony boundaries of the frontal sinus, appropriate management involves exenteration of the mucosa and obliteration of the sinus and nasofrontal ducts

Question 194

Symptoms of frontal sinus mucocele

Answer 194

Mucocele is a rare, late complication of untreated frontal sinus injury. Symptoms include headache and frontal sinus and orbital pain.

Question 195

``` A 21-year-old man is brought to the emergency department one hour after sustaining a fracture of the nose during a fistfight. Which of the following physical findings in this patient is most indicative of a concomitant fracture of the septum? (A) Crepitation (B) Depression of the nose (C) Deviation of the nose (D) Epistaxis (E) Tearing of the mucosa ```

Answer 195

(E) Tearing of the mucosa

Question 196

Most predictive findings of nasal septal fractures

Answer 196

Tearing of the septal mucosa is the most indicative finding, followed by septal deviation, then crepitation. Depression of the nose, deviation of the nose, epistaxis, open nasal wounds, and ecchymosis produced low confidence intervals. Thin-section CT scans were not definitive in many cases.

Question 197

Most common fracture of the face

Answer 197

Nasal bone fracture

Question 198

Incidence of secondary deformity after nasal bone fracture

Answer 198

10-50% Many result from a septal fracture that was unrecognized and untreated at the time of injury.

Question 199

A septal fracture vs the rest of the nose:

Answer 199

A septal fracture destabilizes alignment of the nasal bones during healing and increases breathing difficulties.

Question 200

Management of a nasal septum with a fracture and displacement

Answer 200

A nasal septum with a fracture and displacement must be relocated into the vomerine groove. The fracture should be directly visualized, if possible, and limited septal repositioning or reconstruction should be performed. Internal stitches and splints may be used to help stabilize the reduction.

Question 201

A 35-year-old man has swelling and tenderness of the nose and deviation of the nose to the left after being accidentally struck in the face while playing squash. Intranasal examination shows a localized purple mass on the left side of the septum. A CT scan is shown on page 4. Which of the following is the most appropriate initial management? (A) Immediate closed reduction and placement of an external splint (B) Immediate open reduction of the nasal fractures (C) Immediate incision and drainage of the septal mass (D) Immediate submucous resection of the septal fracture

Answer 201

(C) Immediate incision and drainage of the septal mass

Question 202

If left untreated, septal hematomas cause:

Answer 202

If left untreated, septal hematomas cause fibrosis and narrowing of the nasal passages, distortion of the septum, and/or formation of an abscess. They can also cause pressure necrosis of the septum, leading to septal perforation and eventually to complete necrosis with formation of a saddle-nose deformity. Fracture management is undertaken after the hematoma has been evacuated

Question 203

Nasal fracture management after treatment of septal hematoma: timing

Answer 203

In patients who have significant swelling obscuring the nasal structure, fracture reduction is delayed until the swelling resolves, typically within five to 10 days. If swelling is minimal, then reduction can be performed immediately after evacuation

Question 204

Nasal fracture management timing w/ significant edema

Answer 204

Reduction after swelling resolves, usually in 5-10 days

Question 205

``` A 25-year-old woman sustains a frontal sinus fracture in a motor vehicle collision. On physical examination, there is cerebrospinal fluid rhinorrhea. A CT scan of the head shows displacement of both the anterior and posterior walls and fracture lines extending through the nasofrontal ducts. Which of the following is the most appropriate management? (A) Ablation (B) Cranialization (C) Exenteration (D) Nasalization (E) Obliteration ```

Answer 205

(B) Cranialization Cranialization of the frontal sinus is the most appropriate management of this patient who has a fracture of the posterior table of the frontal sinus with a concomitant cerebrospinal fluid leak. This procedure is often recommended for patients with severe comminution of the posterior table to resolve any cerebrospinal fluid leakage. Bifrontal craniotomy is performed first to repair the dura, and the posterior table of the frontal sinus and associated mucosa are removed. The nasofrontal duct is occluded with a pericranial flap, disrupting the communication of the duct with the frontal sinus. Following surgery, the brain gradually expands to fill the space previously occupied by the frontal sinus.

Question 206

Extentoration of the frontal sinus

Answer 206

Exenteration involves removal of the anterior table of the frontal sinus only. Although it results in a cosmetic deformity, it may be considered in patients who have severe damage to the anterior table resulting from infection and who cannot undergo immediate reconstruction.

Question 207

Nasalization of the frontal sinus

Answer 207

Nasalization is a techniquein which the nasofrontal duct is either stented or enlarged to ensure adequate drainage of the frontal sinus. This procedure is typically used in patients with frontal basilar fractures involving the nasofrontal duct or floor of the sinus.

Question 208

``` A 32-year-old man sustains a fracture of the mandible in a motor vehicle collision. The likelihood of concomitant cervical spine injury in this patient is closest to (A) 10% (B) 20% (C) 30% (D) 40% (E) 50% ```

Answer 208

(A) 10%

Question 209

In patients who sustain facial fractures in motor vehicle collisions, the incidence of cervical spine injury has been shown to range from:

Answer 209

In patients who sustain facial fractures in motor vehicle collisions, the incidence of cervical spine injury has been shown to range from 5% to 15%, according to the results of multiple studies.

Question 210

A 27-year-old man has malocclusion and tenderness around the orbits and bridge of the nose after sustaining facial injuries in a motor vehicle collision. A photograph and CT scan are shown above: Left NOE fracture.. The patient is to undergo open reduction and internal fixation of the fractures. Which of the following is the most appropriate management of the lacrimal system (A) Observation (B) Exploration of the lacrimal duct (C) Placement of a silicone stent (D) Immediate dacryocystorhinostomy (E) Primary repair followed by dacryocystorhinostomy in three months

Answer 210

(A) Observation In this patient who has sustained a naso-orbitoethmoid fracture, the most appropriate management of the lacrimal system is observation. The incidence of injury to the nasolacrimal duct in patients who undergo open reduction and internal fixation of naso-orbitoethmoid fractures but have no overlying lacerations is fairly low. Although swelling or fracture may contribute to blockage of the duct at the time of the initial injury, approximately 90% of patients will experience improvement of symptoms with resolution of the swelling and reduction of the fracture. Exploration and/or manipulation of the duct are not recommended if there is no obvious injury to the duct.

Question 211

Role for exploration and/or manipulation of the nasolacrimal duct if there is no obvious injury

Answer 211

Exploration and/or manipulation of the duct are not recommended if there is no obvious injury to the duct. These procedures may only result in further damage because of the edema and friability of the tissues.

Question 212

A CT scan demonstrates a ZMC fracture in a 25-year-old man who sustained facial injuries in a motor vehicle collision. In this patient, rigid fixation at which of the following points is most likely to result in stable reduction of the fractures? (A) Nasomaxillary buttress, inferior orbital rim, and zygomaticomaxillary buttress (B) Zygomatic arch, central fragment, and nasomaxillary buttress (C) Zygomatic arch, inferior orbital rim, and zygomaticomaxillary buttress (D) Zygomaticofrontal suture, inferior orbital rim, and zygomaticomaxillary buttress (E) Zygomaticofrontal suture, orbital floor, and zygomaticomaxillary buttress

Answer 212

(D) Zygomaticofrontal suture, inferior orbital rim, and zygomaticomaxillary buttress This patient has sustained a fracture of the zygomaticomaxillary complex, also known as a zygoma fracture. To ensure stable reduction of the fracture, rigid fixation is applied at the zygomaticofrontal suture, inferior orbital rim, and zygomaticomaxillary buttress. Partial relapse may occur without this three-point rigid fixation. The orbital floor is often involved in zygomaticomaxillary complex fractures but not in simple fractures of the zygoma. Therefore, open reduction and internal fixation of the orbital floor may not be necessary to ensure correction of the zygomaticomaxillary fracture.

Question 213

To ensure stable reduction of a ZMC fracture, what should be fixed?

Answer 213

To ensure stable reduction of the fracture, rigid fixation is applied at the zygomaticofrontal suture, inferior orbital rim, and zygomaticomaxillary buttress. Partial relapse may occur without this three-point rigid fixation.

Question 214

Facial fractures: Central fragments

Answer 214

Central fragments are associated with naso-orbitoethmoid fractures, not zygomaticomaxillary complex fractures. This fragment is comprised of the ascending frontal process of the maxilla and the descending internal angular process of the frontal bone. It provides the bony support for the medial canthus

Question 215

``` A 25-year-old man has diplopia two days after sustaining an orbital fracture in a motor vehicle collision. On physical examination, he does not have enophthalmos; review of CT scans obtained immediately after injury shows no bony displacement or entrapment of the orbital contents within the fracture.Which of the following is the most appropriate next step in management? (A) Observation (B) Administration of a corticosteroid (C) Administration of a diuretic (D) MRI (E) Immediate operative exploration ```

Answer 215

(A) Observation Conservative management is recommended in this patient who has diplopia after sustaining an undisplaced, stable orbital fracture without entrapment or enophthalmos. Diplopia often occurs following orbital trauma and may be caused by edema, neurovascular or muscle injury, or entrapment of surrounding structures within the fracture.If entrapment is the cause, surgical release should be performed within the first 24 to 48 hours after injury to prevent permanent muscle damage. However, if there is no entrapment, as in this patient, observation for 10 to 14 days is most appropriate. This will allow for resolution of any edema or temporary palsy. Repeat evaluation can then be performed at this time.CT scan, not MRI, is most appropriate for evaluating the condition of the fracture site.

Question 216

A 16-year-old basketball player is undergoing evaluation 12 hours after sustaining a nasal fracture in a basketball game. Physical examination of the fracture site shows marked edema. The radix is stable. A single fracture fragment is displaced from the bony nasal pyramid. Intranasal examination shows septal hematomas bilaterally. Which of the following is the most appropriate management? (A) Drainage of the septal hematomas followed by closed reduction and splinting in three days (B) Immediate operative drainage of the septal hematomas, followed by closed reduction and splinting (C) Drainage of the septal hematomas and intraoral open reduction and internal fixation of the nasomaxillary suture line in three days (D) Closed reduction of the nasal fracture in three days, followed by submucosal resection and inferior turbinate infracture in six months (E) CT scan of the face to rule out a naso-orbitoethmoid fracture, followed by open reduction and internal fixation of the fractures and septoplasty

Answer 216

(A) Drainage of the septal hematomas followed by closed reduction and splinting in three days In this patient who has sustained a nasal fracture with displacement of one fragment, intranasal examination shows septal hematomas bilaterally. Therefore, the most appropriate management is drainage of the hematomas, followed by closed reduction and splinting in three days. It is imperative to drain the hematomas immediately to prevent the development of complications, including thickening of the septum (ie, “cauliflower” deformity) or dissolution and collapse of the septum, which will ultimately result in a saddle-nose deformity. Because this patient has significant swelling, closed reduction should be delayed. After the swelling has decreased (typically at three to five days after injury), the septum and nasal pyramid should be reduced, and the nasal pyramid should then be splinted. Immediate closed reduction is difficult in any patient with significant edema

Question 217

A 23-year-old man is undergoing evaluation one week after sustaining a nasal fracture. Each of the following is appropriate management of this patient’s injuries EXCEPT (A) closed realignment of the nasal fracture with forceps (B) drainage of septal hematomas (C) intranasal packing (D) osteotomy and realignment of the nasal fracture (E) use of a dorsal nasal splint

Answer 217

(D) osteotomy and realignment of the nasal fracture Appropriate management includes incision along the base or most inferior portion of a hematoma (if present), which will allow for drainage and prevent blood from refilling the cavity. In addition, closed reduction is appropriate for septal fractures and deviated nasal bones. Intranasal packing and dorsal nasal splints are typically used to aid in maintaining the reduction. Osteotomy should not be performed in patients with acute fractures because nasal collapse may result. This procedure should be delayed until the fracture has healed significantly.

Question 218

Why is bleeding common with fracture of the nasal bones?

Answer 218

Bleeding is common with nasal trauma because of the rich blood supply of the mucoperichondrium.

Question 219

Why does nasal septal hematoma often occur bilaterally?

Answer 219

Fracture of the nasal septum can lead to hematoma, which frequently occurs bilaterally, as septal fractures communicate between both sides of the nose.

Question 220

Osteotomy and acute nasal fractures

Answer 220

Osteotomy should not be performed in patients with acute fractures because nasal collapse may result. This procedure should be delayed until the fracture has healed significantly

Question 221

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 mid face fractures (E) Open reduction and internal fixation of the midface fractures followed by open reduction and internal fixation of the condylar neck fractures

Answer 221

(D) Open reduction and internal fixation of the condylar neck fractures followed by open reduction and internal fixation of the mid face fractures 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.

Question 222

External fixtures and mandible fractures

Answer 222

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

Question 223

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 week 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

Answer 223

(A) Improper intraoperative seating of the condyles in the glenoid fossae 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 withinthe 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 fixationwould 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.

Question 224

Progressive condylar shortening

Answer 224

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.

Question 225

A 25-year-old man sustains 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

Answer 225

(D) Open reduction and internal fixation with immediate bone grafting 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. 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

Question 226

Clinical findings associated with NOE fractures

Answer 226

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.

Question 227

Bone grafting with NOE fractures

Answer 227

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

Question 228

Immediate vs delayed bone grafting for comminuted NOE fractures

Answer 228

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.

Question 229

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

Answer 229

(D) Orbital floor defect greater than 2 cm 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.

Question 230

Indications for surgical exploration of orbital blow out fracture

Answer 230

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.

Question 231

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

Answer 231

(C) Glue fixation will provide compressive forces comparable to either resorbable or titanium plate and screw fixation 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.

Question 232

Butyl-2-cyanoacrylate

Answer 232

Glue fixation for facial fractures

Question 233

Butyl-2-cyanoacrylate vs plate/screw distraction forces

Answer 233

According to the results of in vitro studies, plate and screw fixation devices have been shown to tolerate higher distraction forces than glue fixation.

Question 234

Butyl-2-cyanoacrylate vs plate/screw for fracture fixation

Answer 234

Plates and screws also provide greater biomechanical stability than butyl-2-cyanoacrylate in bones that absorb large forces, such as the mandible. 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.

Question 235

What limits places/screws in thin bone fragments?

Answer 235

Fixation of thin bone fragments w/ plates/screws is limited by the pull-out strength of the screws to the applied bone segments.

Question 236

``` 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 ```

Answer 236

(B) Lateral orbital wall 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.

Question 237

In a patient who has sustained a fracture of the zygomaticomaxillary complex, the _______________ can be used as landmarks to obtain the most accurate reduction.

Answer 237

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.

Question 238

``` 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 ```

Answer 238

(A) Capsulopalpebral fascia 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.

Question 239

Why has the preseptal transconjunctival incision been used with increasing frequency in recent years?

Answer 239

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.

Question 240

Procedure for a preseptal transconjunctival incision

Answer 240

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.

Question 241

``` 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 ```

Answer 241

(C) Ocular parasympathetic nerves 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.

Question 242

How can ocular parasympathetic fibers be injured during surgery?

Answer 242

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.

Question 243

Clinical findings consistent with compromised ocular parasympathetic nerve function

Answer 243

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.

Question 244

Marcus-Gunn pupil

Answer 244

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.

Question 245

``` 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 ```

Answer 245

(B) Downward cant

Question 246

Most likely directional displacement of ZMC fractures

Answer 246

Fractures of the orbitozygomatic complex can be displaced en bloc or rotationally; most displaced zygomatic fractures are depressed and rotated laterally.

Question 247

A 35-year-old man has persistent enophthalmos 18 months after undergoing open reduction of a fracture of the orbital floor and zygoma. Forced duction testing shows no restriction of eye motion. Which of the following is the most likely cause of this patient's enophthalmos? (A) Fat atrophy (B) Fibrosis of the extra ocular muscles (C) Herniated contents of the orbit within the maxillary sinus (D) Inadequate fracture reduction (E) Scar contracture

Answer 247

(D) Inadequate fracture reduction

Question 248

A 25-year-old man sustains a fracture of the frontal sinus in a motor vehicle collision. A CT scan of the frontal sinus shows a comminuted fracture of the anterior table and a linear nondisplaced fracture of the posterior table. There is no evidence of cerebrospinal fluid leak. Following removal of the anterior table fragments during surgical exploration, methylene blue is instilled into the sinus and passes into the nasal cavity. Which of the following is the most appropriate management? (A) Fixation of the anterior table bone fragments only (B) Enlargement of the nasofrontal duct (C) Ablation of the frontal sinus (D) Cranialization of the frontal sinus (E) Obliteration of the frontal sinus

Answer 248

(A) Fixation of the anterior table bone fragments only

Question 249

A 25-year-old woman is brought to the emergency department after sustaining injuries in a motor vehicle collision. The patient is alert on initial evaluation and has a Glasgow Coma Scale score of 15. On physical examination, there is periorbital ecchymosis onthe right, loss of sensation in the area of the left forehead, ptosis of the right upper eyelid, right-sided ophthalmoplegia, and a fixed, dilated pupil. Consensual light reflex is intact.These findings are most consistent with which of the following? (A) Dehiscence of the levator palpebrae superioris muscle (B) Entrapment of the inferior rectus muscle (C) Orbital apex syndrome (D) Retrobulbar hematoma (E) Superior orbital fissure syndrome

Answer 249

(E) Superior orbital fissure syndrome This patient has findings most consistent with superior orbital fissure syndrome, a high-velocity injury caused by extension of an orbital fracture into the superior orbital fissure. The oculomotor (III), trochlear (IV), and abducens (VI) nerves, and the ophthalmic division of the trigeminal nerve (V1) pass through the superior orbital fissure, which is formed from the greater and lesser wings of the sphenoid bone. Affected patients typically have paralysis of the extraocular muscles and the levator palpebrae superioris muscle resulting from injury to multiple nerves. If the ophthalmic division of the trigeminal nerve is involved, the patient will have anesthesia of the forehead, eyebrow, and upper eyelid.

Question 250

Ophthalmoplegia

Answer 250

Ophthalmoplegia refers to weakness (-paresis) or paralysis (-plegia) of one or more extraocular muscles

Question 251

Superior orbital fissure syndrom occurs when:

Answer 251

A high-velocity injury caused by extension of an orbital fracture into the superior orbital fissure

Question 252

What passes through the superior orbital fissure

Answer 252

The oculomotor (III), trochlear (IV), and abducens (VI) nerves, and the ophthalmic division of the trigeminal nerve (V1) pass through the superior orbital fissure,

Question 253

What forms the superior orbital fissure

Answer 253

The greater and lesser wings of the sphenoid bone

Question 254

Findings of superior orbital fissure syndrome

Answer 254

This most often occurs after a high velocity injury, causing extension of an orbital fracture into the superior orbital fissure. Affected patients typically have paralysis of the extraocular muscles and the levator palpebrae superioris muscle resulting from injury to multiple nerves. If the ophthalmic division of the trigeminal nerve is involved, the patient will have anesthesia of the forehead, eyebrow, and upper eyelid.

Question 255

Orbital apex syndrome

Answer 255

Orbital apex syndrome is characterized by the findings associated with superior orbital fissure syndrome as well as blindness resulting from involvement of the optic nerve.

Question 256

``` During the application of rigid fixation in a 9-year-old child who has sustained a Le Fort I fracture, which of the following permanent tooth buds is at greatestrisk for injury? (A) Canine (B) Central incisor (C) First molar (D) First premolar (E) Lateral incisor ```

Answer 256

(A) Canine

Question 257

The permanent canine teeth, or cuspids, erupt at what age?

Answer 257

The permanent canine teeth, or cuspids, erupt between ages 10 and 11 years.

Question 258

The central and lateral incisors erupt at what age?

Answer 258

The central and lateral incisors erupt between ages 6 and 8 years.

Question 259

The permanent first molars erupt erupt at what age?

Answer 259

The permanent first molars erupt between ages 6 and 7 years,

Question 260

The first premolars erupt erupt at what age?

Answer 260

The first premolars erupt between ages 8 and 9 years.

Question 261

Sequence of permanent tooth eruption

Answer 261

``` Central and lateral incisors (6-8 yo) First molars (6-7 yo) First premolars (8-9 yo) Canines / cuspids (10-11 yo) Second molars (20 yo) ```

Question 262

``` A 24-year-old man sustains a Le Fort I fracture on the left and a Le Fort III fracture on the right in a motor vehicle collision. In this patient, which of the following bones is most likely to be fractured on both sides of the face? (A) Ethmoid (B) Orbital floor (C) Palate (D) Pterygoid plate (E) Zygoma ```

Answer 262

(D) Pterygoid plate

Question 263

Le Fort 1 Fractures

Answer 263

The ethmoid, orbital floor, palate, and zygoma are each involved in some but not all types of Le Fort I fractures. In patients with Le Fort I fractures, the pterygoid plate is most likely to be affected, regardless of the type of fracture, because it lies posterior and thus forms the most posterior aspect of the fracture.

Question 264

``` Which of the following is a late complication following frontal sinus fracture? (A) Cerebrospinal fluid leak (B) Epistaxis (C) Meningitis (D) Mucocele (E) Sinusitis ```

Answer 264

(D) Mucocele

Question 265

Acute complications after frontal sinus fracture

Answer 265

Acute complications within the first few hours after injury can include epistaxis, cerebrospinal fluid leak, meningitis, and intracranial injury.

Question 266

Subacute complications after frontal sinus fracture

Answer 266

The most common subacute complications occurring within the first few weeks following fracture are frontal sinusitis, mucocele, and meningitis.

Question 267

Longterm complications after frontal sinus fracture

Answer 267

Long-term complications, such as osteomyelitis, mucocele, and chronic intracranial or orbital abscesses, can occur as late as several years after injury. Cosmetic deformities may also be seen late.

Question 268

Most complications after frontal sinus fracture occur in which type of fracture?

Answer 268

Because most complications occur in patients with fractures of the posterior table, appropriate reduction of all posterior fragments and repair of all dural tears are recommended.

Question 269

``` In a 32-year-old man who sustained a panfacial fracture in a high-speed motor vehicle collision, what is the approximate risk for concomitant cervical spine injury? (A) 5% (B) 10% (C) 15% (D) 20% (E) 25% ```

Answer 269

(B) 10%

Question 270

``` In a patient who has sustained a fracture of the zygomaticomaxillary complex (tripod fracture), accurate reduction of the fracture components is most likely to be accomplished with the use of which of the following anatomic structures? (A) Inferior orbital rim (B) Lateral orbital wall (C) Orbital floor (D) Zygomatic arch (E) Zygomaticomaxillary plane ```

Answer 270

(B) Lateral orbital wall

Question 271

How to obtain the most accurate reduction after ZMC fracture

Answer 271

In order to obtain the most accurate reduction, the lateral orbital wall and sphenoid wing should be visualized from inside the orbit. This 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; accurate reduction is obtained when these two areas are aligned completely.

Question 272

``` Which of the following fixation materials causes the LEAST amount of scatter on CT scan? (A) Polylactic acid (B) Stainless steel (C) Tantalum (D) Titanium (E) Vitallium ```

Answer 272

(A) Polylactic acid Polylactic acid is not visible on plain radiographs nor on CT scans. Among metals used in fixation, stainless steel alloy (comprised of chromium, nickel, and molybdenum) exhibitsthe most scatter, while titanium and Vitallium (cobalt-chromium alloy) produce the least scatter. Tantalum is not currently used for craniomaxillofacial fixation because it exhibits inadequate mechanical properties

Question 273

Polylactic acid and L-glycolic acid (Lactasorb) and craniomaxillofacial fixation

Answer 273

The copolymer of polylactic acid and L-glycolic acid (Lactasorb) is a nonmetallic substance that is currently used in craniomaxillofacial fixation, is not visible on plain radiographs and/or CT scans, and is completely resorbed within one year following implantation

Question 274

Tantalum and craniomaxillofacial fixation

Answer 274

Inadequate mechanical properties

Question 275

``` Which of the following is the most common cause of posttraumatic enophthalmos? (A) Fat atrophy (B) Increased volume of the bony orbit (C) Ligament disruption (D) Orbital roof defect (E) Soft-tissue contracture ```

Answer 275

(B) Increased volume of the bony orbit

Question 276

In a patient undergoing surgical management of a Le Fort I fracture, rigid fixation is applied using metal plates and screws. When maxillomandibular fixation is removed to confirm the occlusal relationship, a unilateral posterior open bite is noted. Which of the following is the most appropriate next step in management? (A) Fixation with elastic banding on the side of the open bite for four weeks (B) Re-establishment of maxillomandibular fixation for six weeks (C) Removal of all rigid fixation and disimpaction of the maxillary fracture (D) Removal of all rigid fixation followed by wire fixation of the fracture sites (E) Replacement of the metal plates with absorbable (Lactasorb) plates on the side of the open bite

Answer 276

(C) Removal of all rigid fixation and disimpaction of the maxillary fracture If the maxilla has been impacted into the pterygoid plates, the occlusion will be angled superiorly toward the side of impaction. Therefore, if rigid fixation is applied before the fracture site is disimpacted, the patient will have an open bite on removal of maxillomandibular fixation. In order to prevent this, the impacted segments should be mobilized prior to the application of rigid maxillomandibular fixation, and an even plane should be established to correct the open bite.

Question 277

Le Fort I: When the maxilla has been impacted into the pterygoid plates

Answer 277

If the maxilla has been impacted into the pterygoid plates, the occlusion will be angled superiorly toward the side of impaction. Therefore, if rigid fixation is applied before the fracture site is disimpacted, the patient will have an open bite on removal of maxillomandibular fixation. In order to prevent this, the impacted segments should be mobilized prior to the application of rigid maxillomandibular fixation, and an even plane should be established to correct the open bite.

Question 278

A 27-year-old woman has numbness of the left cheek after being hit in the eye with a tennis ball. Radiographs show an orbital blowout fracture. Which of the following is the most likely cause of the numbness? (A) Edema of the skin over the cheek (B) Entrapment of the infraorbital nerve distal to the foramen (C) Fracture of the body of the zygoma (D) Fracture ofthe infraorbital rim (E) Injury of the infraorbital nerve within the orbital floor

Answer 278

(E) Injury of the infraorbital nerve within the orbital floor Patients with pure orbital blowout fractures rarely have involvement or fracture of the infraorbital rim or body of the zygoma. The fracture fragments from the orbital floor and medial orbital wall are typically displaced into the sinus. Edema usually occurs in the periorbital region and not the soft tissues of the cheek.

Question 279

Infraorbital nerve and blowout fracture

Answer 279

A patient who experiences paresthesias of the cheek skin after sustaining a pure blowout fracture of the orbital floor usually has an injury of the infraorbital nerve

Question 280

Course of the infraorbital nerve in the orbital floor

Answer 280

This nerve, which is a branch of the maxillary division of the trigeminal nerve (V2), courses within the inferior orbital canal along the floor of the orbit and exits the body of the zygoma through the infraorbital foramen.

Question 281

``` A30-year-old man sustains an injury to the left side of the face in a fistfight. Radiographs show an isolated fracture of the zygomatic arch; surgical reduction of the fracture is planned. Following incision in the temporal region, the instrument should bepassed immediately beneath which of the following layers of the scalp? (A) Hair follicles (B) Subcutaneous fat of the scalp (C) Superficial temporal fascia (D) Deep temporal fascia (E) Temporalis muscle ```

Answer 281

(D) Deep temporal fascia Because the hair follicles, subcutaneous fat, and superficial temporal fascia are all positioned superficial to the zygomatic arch, passing the elevating device beneath any of these structures will not allow for elevation of the zygoma and may instead result in damage to the frontal branch of the facial nerve.

Question 282

``` In a 29-year-old woman who sustained trauma to the face during a rugby game four weeks ago, intranasal inspection with a nasal speculum shows a perforation of the nasal septum. A physical examination and radiographs obtained in the emergency department at the time of initial injury showed findings consistent with a displaced nasal fracture. Which of the following is the most likely cause of the septal deformity? (A) Foreign body perforation (B) Nasal bone puncture (C) Septal hemangioma (D) Septal hematoma (E) Turbinate bone perforation ```

Answer 282

(D) Septal hematoma

Question 283

``` A 24-year-old man has moderate ectropion three weeks after undergoing open reduction and internal fixation of a malar complex fracture through subciliary and intraoral incisions. Operative exploration of the orbital floor was performed to confirm fracture reduction. Which of the following anatomic sites is the most likely origin of this patient's ectropion? (A) Lateral canthal ligament (B) Orbicularis oculi (C) Orbital septum (D) Skin (E) Tarsus ```

Answer 283

(C) Orbital septum This patient has ectropion that has most likely been caused by edema and scar contracture of the orbital septum.

Question 284

``` A 35-year-old woman sustains blunt trauma to the preauricular region during a field hockey game. Radiographs show a fracture of the condylar neck with medial displacement of the proximal fracture fragment. Which of the following muscles most likely contributes to the fracture displacement? (A) Buccinator (B) Lateral pterygoid (C) Masseter (D) Medial pterygoid (E) Temporalis ```

Answer 284

(B) Lateral pterygoid In this patient who has a fracture of the condylar neck, displacement of the proximal fracture fragment is most likely caused by the action of the lateral pterygoid muscle. This muscle, which has two heads, is the only muscle that inserts directly on the mandibular condyle, on its anterior portion.

Question 285

What is the only muscle that inserts onto the mandibular condyle?

Answer 285

The lateral pterygoid

Question 286

Anatomy of the lateral pterygoid

Answer 286

The inferior head of the lateral pterygoid muscle arises from the lateral pterygoid plate and inserts into the anterior surface of the neck of the condyle; it acts to open the mandible. The superior head arises from the infratemporal crest, infratemporal surface of the greater wing of the sphenoid bone, and a portion of the squamous part of the temporal bone and inserts into the capsule and articular disk of the TMJ; it contributes to the motion of the articular disk.

Question 287

In patients with condylar fractures, the __________ muscle pulls the condylar head __________

Answer 287

In patients with condylar fractures, the unopposed force of the lateral pterygoid muscle pulls the condylar head medially.

Question 288

Anatomy of the medial pterygoid muscle

Answer 288

The medial pterygoid muscle arises within the pterygoid fossa and inserts into the medial surface of the mandibular angle and ramus

Question 289

``` A 45-year-old man sustains an isolated fracture of the body of the zygoma that is displaced inferiorly and posteriorly. The accurate alignment of which of the following anatomic structures provides the most useful guide for surgical reduction of the fracture? (A) Anterior maxillary wall (B) Frontozygomatic suture (C) Inferior orbital rim (D) Lateral orbital wall (E) Zygomatic arch ```

Answer 289

(D) Lateral orbital wall

Question 290

Zygomatic osteotomies for increased anterior projection of the cheek bone will be most beneficial for which of the following patients? (A) A 15-year-old boy who has Treacher Collins syndrome (B) A 23-year-old woman who desires primary cheek augmentation (C) A 32-year-old man who has facial flattening after sustaining panfacial fractures (D) A 45-year-old woman who is undergoing rhytidectomy and bicoronal forehead lifting (E) A 50-year-old man who has loss of malar projection one week after sustaining a zygomatico-orbital fracture

Answer 290

(C) A 32-year-old man who has facial flattening after sustaining panfacial fractures The 32-year-old man with panfacial fractures is the sole candidate of those listed above who should undergo zygomatic osteotomies, which are typically indicated to provide increased malar projection in patients who have scarring or inadequate vascularization of the soft tissues. Panfacial fractures are frequently caused by high velocity injury to the facial skeleton, often resulting in an equal distribution of force to all of the tissues of the face. Scarring and disturbance of soft-tissue vascularization are frequent. Although zygomatic osteotomies are never indicated in patients who have acute injuries, they can be considered if facial deformities persist following fracture repair. In contrast, alloplastic augmentation is the procedure of choice in all other patients who require increased projection; this technique is easier to perform and is associated with fewer complications. The implants are easier to form and mold for the individual face. In the 50-year-old man with inadequate malar projection following zygomatico-orbital fracture, open reduction and internal fixation are most appropriate.

Question 291

Indication for zygomatic osteotomies

Answer 291

Zygomatic osteotomies are typically indicated to provide increased malar projection in patients who have scarring or inadequate vascularization of the soft tissues. Panfacial fractures are frequently caused by high velocity injury to the facial skeleton, often resulting in an equal distribution of force to all of the tissues of the face. Scarring and disturbance of soft-tissue vascularization are frequent. Although zygomatic osteotomies are never indicated in patients who have acute injuries, they can be considered if facial deformities persist following fracture repair. Otherwise, use alloplastic augmentation!

Question 292

Zygomatic osteotomies vs alloplastic augmentation

Answer 292

Zygomatic osteotomies are typically indicated to provide increased malar projection in patients who have scarring or inadequate vascularization of the soft tissues. Alloplastic augmentation is the procedure of choice in all other patients who require increased projection; this technique is easier to perform and is associated with fewer complications. The implants are easier to form and mold for the individual face.

Question 293

In patients without loss of posterior vertical height, which of the following is the most appropriate duration of maxillomandibular fixation (MMF) for treatment of minimally displaced bilateral subcondylar fractures of the mandible? A) 1 week B) 4 weeks C) 8 weeks D) None; stabilize mandible with gunning splint for 8 weeks E) None; treat patient with soft diet

Answer 293

B) 4 weeks Closed reduction has historically been the standard treatment for subcondylar fractures of the mandible. Its widespread use is attributed to the idea that closed reduction results in fewer complications with similar functional and aesthetic outcomes compared with open reduction and internal fixation (ORIF). For instance, complications such as facial nerve damage and excessive scarring are significantly decreased because of the noninvasive nature of this approach. However, as highlighted by ongoing debate, a consensus regarding outcomes between open and closed reduction is not evident in the literature. In short, some studies conclude that both approaches produce roughly similar results, while other studies have associated an array of unfavorable outcomes with closed reduction. These outcomes include facial asymmetry, deviation upon mouth opening, skeletal malocclusion, and chronic pain of the temporomandibular joint (TMJ). The fact that many of these parameters lack standardization in the duration of the treatment further obscures the debate. Larger studies with consistent parameters are needed to reassess outcomes with the surgical techniques and technology present today. However, it is unlikely that a large enough trial will deliver granular evidence to conclusively quell this debate. Another controversial point regarding closed reduction is the length of time a patient should spend in maxillomandibular fixation (MMF). Many surgeons choose to apply fixation for a very short period (i.e., 2 weeks) to avoid ankylosis of the TMJ secondary to forced immobilization during MMF. While the etiology of ankylosis is not completely understood, it is hypothesized that trauma leading to intracapsular hematoma results in fibrosis and excessive bone formation, ultimately causing hypomobility of the affected side. Given the current hypothesis, ankylosis of the TMJ is most likely a manifestation of direct injury within the joint capsule or condylar head itself. It is imperative to point out that as a result, there should be a lower risk of ankylosis in subcondylar fractures compared with fractures of the condylar head. Therefore, the position of the fracture line relative to the joint capsule should be closely examined, and a longer period of MMF should be employed if there is no involvement of the condylar head, disc, or capsule. A longer period of MMF commonly results in better union of the fractured segments with no increase in the incidence of ankylosis. In a nondisplaced fracture or minimally displaced fracture with a functional occlusion, 4 to 6 weeks of MMF is recommended, followed by 2 to 3 weeks of guiding elastics. The same treatment applies in the case of a nondisplaced bilateral fracture. However, this scenario is less common because the force parameters to cause the bilateral fracture are often greater and tend to displace the fracture fragments significantly, necessitating ORIF. The patient will most likely develop shortening of the masseter muscle and stiffness with prolonged immobilization during 8 to 10 weeks. With bilateral instability, the fracture pattern is unstable and soft diet alone would likely lead to malocclusion. A gunning splint is often used in edentulous mandible only and is not functional MMF.

Question 294

Which of the following concomitant fractures is most likely to affect the perceived reduction when performing open reduction and internal fixation of a zygomaticomaxillary complex fracture? A) Anterior maxillary wall comminution with loss of bone B) Articular tubercle of the zygomatic arch C) Le Fort I fracture D) Naso-orbito-ethmoid fracture E) Orbital floor blowout fracture

Answer 294

D) Naso-orbito-ethmoid fracture When surgically reducing a zygomaticomaxillary complex (ZMC) fracture (tripod fracture), the surgeon uses multiple landmarks to confirm adequate reduction. The lateral orbital sidewall is the most reliable landmark as it is a three-dimensional landmark (junction of frontal bone, sphenoid, and zygoma). Other landmarks include the zygomaticofrontal suture, the zygomaticomaxillary lateral buttress, the orbital rim, and the zygomatic arch. Because the orbital rim is easily visualized, surgeons may rely heavily on this landmark for alignment. Sometimes due to orbital swelling or poor visualization, the lateral orbital wall is not easy to assess for adequate reduction of the fracture. If the orbital rim appears to be reduced (well aligned) but the ZMC fracture is not well reduced, then an ipsilateral unreduced naso-orbito-ethmoid (NOE) fracture is the most likely reason. It is important to reduce the NOE fracture before aligning the orbital rim for the ZMC fracture reduction. Postoperative deformity will ensue if the NOE fracture is not reduced and the ZMC is plated in position based on the orbital rim alignment. The deformity will lead to enlarged orbital volume and facial widening, loss of malar projection, and enophthalmos. Proper reduction and initial management are important, as secondary corrections are more difficult and have more morbidity.

Question 295

``` Isolated orbital fractures most commonly occur in which of the following bones? A) Ethmoid B) Frontal C) Lacrimal D) Maxillary E) Zygomatic ```

Answer 295

D) Maxillary quite thin behind the infraorbital rim, and is perforated by the infraorbital nerve passing in a canal below it. Most pure blowout fractures involve the orbital floor. Long-term epidemiologic data regarding the natural history of orbital bone fractures are important for the evaluation of existing preventive measures and for the development of new methods of injury prevention and treatment.

Question 296

A 24-year-old man is brought to the emergency department after being ejected from a vehicle at high speed. Physical examination shows massive oronasal bleeding and an unstable maxilla. He is hemodynamically unstable, and other sources of marked bleeding have been excluded. Endotracheal intubation is performed. Which of the following is the most appropriate next step in management? A) Establishment of mandibulo-maxillary fixation B) Nasendoscopy with bipolar coagulation C) Operative ligation of the external carotid arteries D) Placement of anterior and posterior nasal packing E) Transcatheter embolization

Answer 296

D) Placement of anterior and posterior nasal packing After establishing an airway, the best first step to controlling massive oronasal hemorrhage is nasal packing. This can be quickly accomplished by inflating Foley catheters in the posterior choanae, followed by anterior packing with either a nasal tampon or ribbon gauze. Nasal packing has been shown to control bleeding in 29% of such patients and decrease it in another 44% of patients. Establishment of mandibulo-maxillary fixation (MMF) may also control oronasal hemorrhage. However, achieving MMF in the emergency department is often limited by the availability of fixation devices and is complicated by the presence of an endotracheal tube. Emergent transcatheter arterial embolization, when available, is highly effective in identifying and controlling oronasal hemorrhage when packing has failed to do so. The internal maxillary and superficial temporal arteries are most often responsible for such bleeding. Operative ligation of the external carotid arteries is rarely effective to control oronasal hemorrhage due to rich collateral blood flow in the head and neck. The utility of nasendoscopy is limited in the presence of marked bleeding as visualization is poor and the bleeding vessel may not be readily visible.

Question 297

``` A 38-year-old truck driver is examined in the emergency department following a motor vehicle collision. He is sedated and intubated on a spine board. On examination, ecchymoses over the cheeks, swelling over the left jaw, and pulsation of the left globe are noted. Which of the following is the potential fracture of most concern? A) Mandibular body B) Medial maxillary buttress C) Nasal bone D) Orbital roof E) Zygomatic-malar complex ```

Answer 297

D) Orbital roof Fractures of the orbital roof that enter the middle cranial fossa may allow communication between the cavernous sinus and the carotid artery. Other findings include associated bruit and ipsilateral blindness, which would not be appreciated in the obtunded patient. The remaining fractures are important but are not as critical as a carotid-cavernous fistula.

Question 298

Proper reduction of an isolated zygoma fracture requires reduction and realignment of which of the following? A) Zygomaticofrontal suture, zygomaticomaxillary buttress, and infraorbital rim B) Zygomaticofrontal suture, zygomaticomaxillary buttress, and orbital floor C) Zygomaticofrontal suture, zygomaticonasal suture, and infraorbital rim D) Zygomaticomaxillary buttress, infraorbital rim, and nasomaxillary buttress E) Zygomaticomaxillary buttress, orbital floor, and alveolus

Answer 298

A) Zygomaticofrontal suture, zygomaticomaxillary buttress, and infraorbital rim A zygoma fracture involves displacement of the zygoma that articulates with the frontal bone, maxilla, and sphenoid. In order to stabilize the fracture after adequate reduction, the zygomaticofrontal, zygomaticomaxillary buttress, and infraorbital rim need to be stabilized. If there is a large (>2 cm2) defect in the orbital floor after reduction, reconstruction of the orbital floor is also necessary to prevent enophthalmos. Although the nasomaxillary buttress is one of the vertical buttresses of the face, the zygoma does not articulate with the nasal bones.

Question 299

``` A 23-year-old man sustains multiple fractures to the middle and upper face during a motor vehicle collision. The patient reports disturbances of smell immediately afterwards. Injury to which of the following bones is the most likely reason for this patient’s anosmia? A) Ethmoid B) Frontal C) Nasal D) Sphenoid E) Vomer ```

Answer 299

A) Ethmoid The cribriform plate is the horizontal component of the ethmoid bone which supports the olfactory bulb and creates a passageway for the olfactory nerves. The cribriform plates (right and left) have many foramina that act as passageways for olfactory nerves and are in intimate contact with the meninges. In addition to anosmia (loss of smell), injury to the cribriform plate may cause tearing of the meninges with cerebrospinal fluid leakage. The crista galli is a midline prominence of the ethmoid, immediately above the cribriform plates, which serves as a point of attachment for intracranial soft tissue. Other components of the ethmoid bone are the vertical portion and the lateral masses. The vertical portion is called the perpendicular plate, which forms part of the nasal septum. The lateral masses of the ethmoid bone contain a plate of bone called the lamina papyracea, which forms part of the medial orbital wall and the ethmoid air cells. While anosmia and taste abnormalities can occur following a variety of facial fracture patterns, including frontal bone, naso-orbital-ethmoid, nasal, Le Fort, and zygoma, the close anatomic relationship of the ethmoid cribriform plate to the olfactory nerve makes it most likely.

Question 300

``` A 21-year-old woman comes to the emergency department because she has had ocular pain and decreased vision since she was struck in the face with a bottle 2 hours ago. On examination in a dark room, both pupils constrict when a light is shone in the right or left sides directly. When the light is shifted from the right to the left, the pupils dilate. Which of the following is the most likely pathologic condition in this patient? A) Central retinal artery occlusion B) Oculomotor (III) nerve injury C) Preexisting cataract D) Symmetrical acute glaucoma E) Vitreous hemorrhage ```

Answer 300

A) Central retinal artery occlusion A Marcus Gunn pupil is a relative afferent pupillary defect caused by a lesion of the optic nerve (between the retina and the optic chiasm) or severe retinal disease. It is observed during the swinging-flashlight test whereupon the patient's pupils constrict less (therefore appearing to dilate) when a bright light is swung in front of the unaffected eye to the affected eye. The affected eye still senses the light and produces pupillary sphincter constriction to some degree, albeit reduced. Conditions that do not cause a Marcus Gunn pupil include cataracts, vitreous hemorrhage, injury to the oculomotor nerve (cranial nerve III), or symmetrical acute glaucoma.

Question 301

``` A 23-year-old man is brought to the emergency department unconscious after a head-on motor vehicle collision. Physical examination shows left periorbital bruising. When a light is shined into the left eye, no pupillary constriction is noted, and thereafter, the light is shined into the right eye, and both pupils constrict. When the light is subsequently shined again into the left eye, the right pupil constricts and the left pupil dilates. Which of the following best explains this finding? A) Extraocular muscle entrapment B) Hyphema C) Inadequate brain perfusion D) Optic nerve injury E) Tentorial herniation ```

Answer 301

D) Optic nerve injury The vignette illustrates findings consistent with a Marcus Gunn pupil. A lesion at the level of the posterior globe (retina) and optic nerve anterior to the chiasm alters the afferent response normally expected from shining a light in the eye. The test is done by shining a light in the pupil of the affected side first, and this will cause little or no constriction on that side, yet there will be a consensual response on the normal side. Then, the light is shined in the normal pupil, resulting in constriction of both pupils (normal ipsilateral and consensual response). The third step is to swing the light back to the injured side, and this typically will cause paradoxical dilatation of the affected pupil. A fracture in the posterior orbit may cause pressure on the optic nerve directly by impingement of a fracture fragment or from hematoma. Extraocular muscles control the directionality of the globe for the purpose of binocular vision. There is no direct distal anatomical connection to the pupillary sphincter muscle (parasympathetic) or the iris dilator (sympathetic), both of which control pupillary size. However, there is a proximal commonality in that some extraocular muscles (superior/medial/inferior recti, inferior oblique) and the pupillary muscles are supplied by the oculomotor nerve. Most commonly, it is the inferior oblique with or without the inferior rectus muscle that is entrapped in an orbital floor fracture, and thus has no direct bearing on pupillary size. Therefore, pupils should react normally in an isolated orbital floor fracture with muscle entrapment. Hyphema is the presence of blood in the anterior chamber. It does not cause a Marcus Gunn pupil, or any other abnormal pupillary reaction. The pupils in a patient with inadequate brain perfusion are usually dilated and fixed, or react sluggishly to light, but always symmetrical. In tentorial herniation, due to a laterally expanding intracranial hematoma, the oculomotor nerve is susceptible to compression as it exits the mid brain. The pupillary examination will show one ipsilateral dilated pupil that is fixed or sluggish, and the globe will be laterally displaced due to the unopposed tone generated by cranial nerve VI on the lateral rectus muscle over a paralyzed medial rectus muscle. Normal pupillary constriction as a reaction to light begins with a light stimulus on the retina that triggers a signal via afferent fibers in the optic (II) nerve. These fibers connect to the pretectal nucleus and both Edinger-Westphal nuclei. A response is generated from there through parasympathetic fibers via the oculomotor (III) nerve, which supplies the sphincter pupillae.

Question 302

``` A 35-year-old man is evaluated because of pain in one of the right lower molar teeth 6 months after he underwent open reduction and internal fixation of a right mandibular angle fracture. Examination shows grayish discoloration and tenderness to axial percussion in the mandibular second molar. A panoramic x-ray study (Panorex) shows an intact mandibular second molar with 1.5-cm radiolucency at its apex. Which of the following is the most likely cause of these findings? A) Dentigerous cystnsufficiency B) Mucous retention cyst C) Odontogenic keratocyst D) Periapical cyst E) Traumatic bone cyst ```

Answer 302

D) Periapical cyst The periapical cyst is the most common odontogenic cyst. The usual etiology is a nonviable tooth that becomes infected, leading to necrosis of the pulp. Toxins exit the apex of the tooth, leading to periapical inflammation leading to a radiolucency seen on x-ray study. The dentigerous cyst is the second most common odontogenic cyst which develops within the normal dental follicle surrounding an unerupted tooth such as a mandibular or maxillary third molar or maxillary canine. Most are asymptomatic and found incidentally on x-ray study. The odontogenic keratocyst or OKC is the third most common odontogenic cyst. It is a great mimic and can have a wide variety of clinical presentations. These cysts are rapid growing and aggressive and can be difficult to remove; recurrence rates are high. They are also a component of the basal cell nevus syndrome. Mucous retention cyst, or mucocele, is a pseudocyst that arises from trauma to the minor salivary glands in the lips. Traumatic bone cyst is a self-limiting radiolucent lesion of uncertain etiology that forms an empty or fluid-filled cavity most commonly within the mandible but also elsewhere in the body.

Question 303

``` A 25-year-old man comes to the office for evaluation of unilateral proptosis, visual impairment, and limitation of ocular movements. History includes basilar skull fractures and repair of panfacial fractures 4 weeks ago. On physical examination, the left eye appears to be pulsating. Which of the following is the most appropriate next step? A) Beta-2 transferrin assay B) Carotid duplex C) Cerebral angiography D) Craniotomy E) Noncontrast CT scan ```

Answer 303

C) Cerebral angiography This case described represents the classic presentation of a posttraumatic carotid-cavernous fistula (CCF). Symptoms include pulsatile proptosis, ocular and orbital erythema, chemosis, diplopia, headaches, and visual loss. This pathology occurs through abnormal connections between the internal carotid artery and the cavernous sinus, and, on rare occasions, may appear between the internal carotid or branches of the external carotid artery and the venous plexus of the skull. Traumatic CCF can lead to blindness as the disorder progresses and, in rare cases, can result in paralysis, unconsciousness, and even death. It is important that clinicians operating on the craniofacial region, and especially those who manage craniofacial trauma, have a thorough understanding of this potentially lethal entity. Although CCF occurs rarely after craniofacial trauma, this disorder is thought to occur relatively frequently in patients with basilar skull fractures. Once there is a suspicion, a prompt evaluation of the arterial vasculature around the cavernous sinus is required. Most commonly, a cerebral angiogram is used to make the diagnosis and, using related techniques, a variety of curative measures (e.g., embolization) can then be enacted. A craniotomy-type modality would be relegated to only the most refractory of cases and would be for cure and not diagnosis. A noncontrasted CT scan would only show posttraumatic bony derangements. Beta-2 transferrin assay could be used if there is an accompaniment of clear rhinorrhea to rule out a craniospinal fluid leak. CCF can be mistaken for other pathologies such as an orbital apex syndrome or even stroke. The latter suspicion may lead to the ordering of a carotid duplex, which would be expected to be normal.

Question 304

An 18-month-old girl is brought to the office because of a soft spot with pulsations on the right parietal region of her skull. At age 6 months, the patient sustained a linear skull fracture due to head trauma, which was managed nonoperatively. CT scan shows a growing skull fracture. Which of the following is the most likely cause of this patient's growing fracture? A) Dural injury at the time of the fracture B) Genetic bone healing disorder C) Isolated right unicoronal craniosynostosis D) Patent anterior fontanelle E) Trauma-related infection

Answer 304

A) Dural injury at the time of the fracture Growing skull fractures occur in children. If a child sustains a fracture that appears linear but has an underlying dural injury, then the fracture may fail to heal. As the skull continues to grow, so does the cranial defect. Trauma alone, open fontanelles, genetic bone disorders, and craniosynostosis are not associated with growing skull fractures. Children under 2 years of age have a tremendous ability to regenerate bone and heal fractures or even large defects. Having normal, healthy dura is very important to bone healing.

Question 305

``` A 14-year-old boy is brought to the emergency department after a fall. Physical examination shows ocular entrapment. A CT scan is shown. Surgical correction is planned. Which of the following is the most appropriate location for incision in this patient? A) Bicoronal B) Lateral brow C) Orbital rim D) Subciliary E) Transcaruncular ```

Answer 305

E) Transcaruncular The CT scan shows an isolated medial wall fracture with entrapment of the medial rectus muscle. The transcaruncular approach can be used for isolated medial wall surgery or combined with a retroseptal transconjunctival approach to the orbital floor (with or without a lateral canthotomy). Although a bicoronal incision will give the necessary exposure to reduce the entrapment and repair the fracture, it has a higher morbidity associated with it, primarily in regards to blood loss and scarring. In this case, it would be excessive in regards to what is needed to expose and treat an isolated medial wall fracture. The bicoronal incision is more appropriate in complex cases where multiple fractures are involved or if access to a naso-orbital-ethmoid or frontal sinus fracture is needed. In this case, subciliary, orbital rim, or lateral brow incisions would not give adequate exposure to reduce the entrapped muscle and repair the fracture.

Question 306

``` A 27-year-old man is brought to the emergency department after he sustained a small-caliber gunshot wound through the cheek, obliterating the intraoral orifice of the parotid duct. Which of the following is the most appropriate management? A) Ligation B) Primary repair C) Secondary intention healing D) Stenting E) Superficial parotidectomy ```

Answer 306

D) Stenting It is recommended that injury to the orifice of the parotid duct be managed with a stent or a drain to maintain patency during healing and guide the flow of saliva into the mouth. Allowing the ductal injury to heal secondarily will likely result in blockage of the orifice with scar tissue, which could lead to a sialocele or cutaneous fistula. Ligation of the proximal duct is recommended for extensive injuries of the glandular/duct system in which neither end of the duct is amenable to repair. This will result in eventual atrophy and loss of function of the parotid gland. Primary repair alone would not be recommended given the degree of soft-tissue loss and contusion with this mechanism of injury. Superficial parotidectomy would be considered for management of chronic glandular/duct system fistulas.

Question 307

A 33-year-old man is brought to the emergency department after he is struck in the forehead with a baseball bat. The patient is awake and alert. Examination shows an obvious deformity in the frontal region. Emergency CT scan shows a displaced and comminuted fracture of the anterior wall of the frontal sinus and a nondisplaced fracture of the posterior wall. The frontonasal duct is patent. Which of the following is the most appropriate treatment? A) Cranialization of the sinus B) Craniotomy C) Obliteration of the sinus and fat grafting D) Observation and intravenous administration of antibiotics E) Open reduction and internal fixation of the anterior wall of the frontal sinus

Answer 307

E) Open reduction and internal fixation of the anterior wall of the frontal sinus Frontal sinus fractures can be assessed by patency of the nasofrontal duct and by whether the fracture involves the anterior wall of the sinus, the posterior wall, or both. In this case, CT scanning shows significant damage to the anterior wall and a minimal fracture in the posterior wall. The normal nasofrontal duct would allow salvage of the sinus with minimal risk of a mucocele or an infection. The underlying brain is uninvolved, so craniotomy is unnecessary. The obvious deformity indicates open reduction and fixation, and because the posterior wall is minimally involved, repair of the anterior wall without craniotomy could be performed.

Question 308

``` A 25-year-old man comes to the office 12 hours after sustaining a maxillofacial injury during a bicycle collision. Physical examination shows that the injured tooth is stable but sensitive to cold liquids, hot liquids, and air. No other abnormalities are noted. The patient?s pain suggests a fracture extending into which of the following? A ) Alveolar bone B ) Cementum C ) Dentin D ) Enamel E ) Pulp ```

Answer 308

C ) Dentin Dental trauma can result from a variety of mechanisms. Significant trauma should be evaluated completely in the emergency department, but injury that is isolated to the teeth can be managed in an outpatient setting. Tooth fractures can be minor, involving only the outer enamel layer, or more significant. Beneath the enamel is the dentin. This yellowish substance overlays and protects the inner tooth pulp. The visible and exposed one third of the tooth is the crown; it consists of outer enamel, inner dentin, and a small amount of the pulp. The two thirds of the tooth in the alveolar bone is called the root and consists of outer cementum, inner dentin, and the pulp chamber. X-ray studies are useful to diagnose the extent of a dental facture. The sensitivity to cold and air that the patient is experiencing suggests a deeper fracture extending into the dentin. Prolonged exposure of the dentin is not only painful but also risks infection that can progress into the pulp and destroy the tooth. The tooth should be capped soon, and follow-up x-ray studies should be performed in 3 to 4 months to make sure that the pulp has not died. Treatment of an injury to the pulp itself would require extracting the dying tooth and replacing it with a prosthetic. Alternatively, a root canal — removing all the dying pulp and filling the tooth — can be performed to avoid extraction. Fractures of the alveolar bone cause the teeth to be very unstable. An arch wire is applied while the bone heals. The tooth is then assessed with x-ray study to make sure it is viable. A root canal may be required in the future.

Question 309

A 5-year-old boy is evaluated because of downward and lateral displacement of the left globe and diplopia that has increased steadily for the past 18 months. History includes open reduction and internal fixation of a frontal bone fracture at 2 years of age. An image is shown. This deformity was most likely caused by which of the following at the time of repair? A ) Failure to obliterate the frontal sinus B ) Failure to recognize dural injury and insufficiency C ) Failure to repair periorbital lacerations D ) Poorly aligned bony fixation E ) Use of absorbable plates

Answer 309

B ) Failure to recognize dural injury and insufficiency Head injuries in infants and young children accompanied with skull fracture often contain dural laceration. Although rare in occurrence, when these dural tears are not recognized (especially when extensive), a growing skull fracture (GSF) can occur. Repair of these dural tears acutely prevents the development of GSF and the potential for secondary cortical injury. The frontal sinus, unlike the maxillary and ethmoid sinuses, is not present at birth and only starts to develop at age 2 years, which, in this case, was when the original repair was performed. Thus, obliteration of the sinus was not warranted. Lacerations of the periorbita, poor bone fixation, and the use of absorbable plates are not linked to GSF.

Question 310

A 23-year-old male pitcher is struck in the face with a baseball during practice and sustains an isolated blowout fracture of the medial orbital wall. A transcaruncular approach is chosen for exposure. After incising the medical conjunctiva, dissection is best carried out between which of the following two structures to reach the posterior lacrimal crest? A ) Inferior rectus muscle and capsulopalpebral fascia B ) Lockwood ligament and inferior oblique muscle C ) Medial canthal ligament and lacrimal duct D ) Medial orbital septum and Horner muscle E ) Whitnall ligament and medial rectus muscle

Answer 310

D ) Medial orbital septum and Horner muscle The appropriate plane of dissection is between the medial orbital septum and Horner muscle to expose the periosteum immediately posterior to the posterior lacrimal crest. This approach attempts to minimize injury to the Lockwood ligament which is more inferior and the lacrimal sac which is more anterior. Preservation of the septum will minimize spillage of fat into the surgical field.

Question 311

``` A 45-year-old woman is evaluated because of enophthalmos caused by trauma to the left orbit sustained 6 months ago. Which of the following is the minimum increase of orbital volume that can result in post-traumatic enophthalmos? A ) 1% B ) 5% C ) 10% D ) 25% E ) 50% ```

Answer 311

B ) 5% If the anatomical volume of the bony orbit is increased as a result of fracture displacement following trauma or inadequate restoration of the normal anatomy, patients may develop enophthalmos. This may be seen with an increase in volume in excess of 5% and may be commonly encountered following fracture of the orbital floor or the medial wall of the orbit.

Question 312

``` A 28-year-old man comes to the office for consultation regarding correction of a residual deformity of the right infraorbital region 2 years after undergoing open reduction and internal fixation and repair of lacerations for an open orbitozygomatic fracture. Examination shows infraorbital soft-tissue atrophy. No enophthalmos or bony stepoff is noted. Examination of the eyes shows no abnormalities. CT scan shows healed fractures with good bony alignment. Which of the following is the most appropriate surgical intervention for correction of this deformity? A ) Alloplastic prosthesis B ) Fat grafting C ) Rhytidectomy D ) Rib grafting E ) Scapular flap coverage ```

Answer 312

B ) Fat grafting The patient has a small area of soft-tissue atrophy, which in the context of his history is likely due to fat atrophy. His bony structure is adequate and symmetrical, but he lacks subcutaneous fat. For this reason, restoration of the defect is best approached by replacing missing soft tissues, rather than enhancing the support framework. The localized nature of the defect makes it ideal for an injectable soft-tissue filler. When harvested and transferred correctly, fat grafting has shown to have high percentage rates in permanency, serving well as a soft-tissue filler. Other fillers that are based with collagen, hyaluronic acid, calcium hydroxyapatite, and poly-L lactic acid have the drawback of being temporary, but could also be considered in the absence of donor areas for fat graft. Alloplastic prostheses are more suited for framework deficiencies. Besides, the unique configuration of the contour deficiency in the scenario described makes it less likely that a pre-shaped prosthesis is going to provide symmetry. A prosthesis in this case would be very palpable, due to the thin soft-tissue covering. Alloplastic prostheses are more likely to cause infection and seroma compared with autologous tissue. A rhytidectomy would not be indicated in this case because it is a procedure that is designed to reposition and/or suspend displaced soft tissues. The contour defect would most likely persist following rhytidectomy. Rib grafts have been used for the correction of late deformities following inadequate treatment of depressed orbitozygomatic fractures. The aim is to reestablish facial projection as determined by the degree of depression of the skeletal framework. Rib grafts are not indicated as a soft-tissue filler. Free scapular flaps are too bulky for the limited size defect of this patient’s face. However, for a larger defect, such as in Romberg disease, it provides suitable correction.