Facial Trauma Flashcards Preview

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Flashcards in Facial Trauma Deck (209):
1

What is the craniofacial ratio in adulthood

0.0840277777777778

2

What is the craniofacial ratio at birth

0.334027777777778

3

How many deciduous teeth are there

20

4

In an adult, what # is the right 3rd molar of the mandible

32

5

What is the appropriate tetanus prophylaxis for a patient with a tetanus-prone wound, who has not been previously immunized

0.5 ml absorbed toxoid and 250 units of human tetanus immune globulin.

6

What is the proper tetanus prophylaxis for a patient with a tetanus-prone wound, who last received a booster 7 years ago'

0.5 ml absorbed toxoid.

7

What do "microplates" refer to

1.0 mm screw applications.

8

In what % of the population is the nasofrontal duct a true duct

15% (in 85% it exists as a foramen draining directly into the nasal cavity).

9

How long should immobilization typically be maintained in children

2 - 3 weeks.

10

Where is this located in relation to the lateral canthus

2 em inferior.

11

What do "miniplates" refer to

2.0 mm, 1.5 mm, or 1.3 mm screw applications.

12

What % of mandible fractures are associated with cervical spine injury

2.6%.

13

What post-orbital fracture visual acuity scores are associated with a return to normal acuity after treatment

20/400 or better.

14

Where are the anterior and posterior ethmoid arteries and optic canal in relation to the anterior lacrimal crest

24 - 12 - 6 rule: anterior ethmoid artery is approximately 24 mm posterior to the lacrimal crest; the posterior ethmoid artery is 12 mm posterior to the anterior ethmoid artery; the optic canal is 6 mm posterior to the posterior ethmoid artery.

15

What is the typical long-term interincisal opening after surgical correction of TMJ ankylosis

25 - 28 mm.

16

What % of patients with ZMC fractures have other associated facial injuries

25%.

17

What % of thoracic perforations will be missed with water-soluble contrast agents

25%.

18

What is the incidence of permanent scleral show with the subciliary approach

28%.

19

What is the normal intercanthal width

30 - 35 mm in Caucasians or roughly the width of the alar base.

20

How far posterior should dissection proceed when placing a Medpor implant for defects of the posterior convex orbital floor

4 em.

21

What % of mandible fractures are associated with other injuries

40 - 60%.

22

What is the average depth of the orbit

40 -50 mm.

23

What is normal interincisal opening

40 -50 mm.

24

What % of cervical perforations will be missed with water-soluble contrast agents

50%.

25

What are the indications for endoscopic optic nerve decompression after facial trauma

66% reduction in amplitude of the visual-evoked response, loss of red color vision, bony impingement on the optic canal, afferent papillary defect.

26

What is the incidence of persistent diplopia after orbital reconstruction

7%.

27

What is the incidence of infection after mandible fracture

7%.

28

Cerebral perfusion-directed therapy attempts to maintain CPP at or above what

70 mm Hg.

29

What is the sensitivity of barium in detecting perforations

80- 90%.

30

How much force is required to fracture the frontal sinus

800 - 2200 lbs.

31

How are they numbered

A to T.

32

What is the best way to treat mandible fractures in infants

Acrylic splints x 2 - 3 weeks.

33

What is the "bowstring sign"

An obvious give that occurs with lateral tension on the lower lid, indicating disruption of the medial canthal tendon.

34

What is the most likely mechanism of injury for bilateral condylar fractures

Anterior blow to the chin.

35

What are the 3 limbs of the medial canthal tendon

Anterior, superior and posterior limbs.

36

What are the contraindications to primary closure of bites

Any human bite; animal bites seen after 5 hours of injury; all avulsion injuries from any animal bite.

37

What are the weakest areas of the mandible

Area around the 3rd molar, socket of the canine tooth, and the condyle.

38

What is the strongest predictor of negative outcome in trauma patients

Arterial hypotension

39

Where are inferiorly positioned plates placed

At the inferior border of the mandible to avoid the neurovascular bundle.

40

What is the treatment for a nondisplaced posterior table fracture with a CSF leak

Bed rest with head elevation +/lumbar drain; cranialization considered if not resolved after 5 - 7 days.

41

What is the general approach for repair of panfacial fractures

Begin laterally, work medially, and correct NOE and nasal septal fractures last; frontal fractures should be repaired before midface fractures.

42

What is the general approach to repair of LeFort III fractures

Begin stabilization at the cranium then work caudally.

43

What are the relative indications for open reduction of a condylar fracture

Bilateral condylar fractures in an edentulous patient when M MF is impossible, condylar fractures when MMF is not recommended for medical reasons, bilateral condylar fractures associated with midface fractures.

44

Anterior open bite suggests which type of fracture

Bilateral condylar fractures.

45

What is the most serious complication after orbital reconstruction

Blindness.

46

What can be done for trismus that does not respond to brisement force

C oronoidectomies.

47

Which tooth has the longest root

Canine.

48

What is a type I I NOE fracture as described by Markovitz et al

Comminuted, but identifiable, central fragment.

49

What is a type C ZMC fracture

Complex fracture with comminution of the zygomatic bone.

50

Which mandible fractures require ORI F with bicortical screws

Complex open fractures that are displaced, comminuted, or infected.

51

Rigid fixation is based on what two means of stabilization

Compression and splinting.

52

Why should compression plates be over-contoured by 3° - 5°

Compression at the buccal surface tends to produce spreading on the lingual side; over-contouring will overcome this.

53

Which parts of the mandible are most commonly fractured

Condyle (36°/o), body (21°/o), and angle (20%).

54

Which part of the mandible is most commonly fractured in children

Condyle.

55

What are the typical physical findings of a unilateral condylar neck fracture

Contralateral open bite and ipsilateral chin deviation.

56

What is the "workhorse" for exposure of the nasoethmoidal region

Coronal approach.

57

What is the indication for surgical treatment of isolated anterior table fractures

Cosmetic deformity.

58

What is the definition of cerebral perfusion pressure (CPP)

CPP = mean arterial pressure (MAP) - intracranial pressure (ICP).

59

What are the potential complications of endoscopic optic nerve decompression

CSF leak, carotid artery injury, transection of the ophthalmic artery, orbital fat herniation.

60

What is a potential complication of this approach

Damage to the temporal fat pad, resulting in temporal wasting.

61

Which teeth can be used in children between the ages of 5 and 8 for immobilization

Deciduous molars.

62

What are the most common injuries associated with facial trauma in children

Dental injuries.

63

What are the 3 approaches to zygomatic arch fractures

Direct percutaneous, temporal (Gillies), and hemicoronal approaches.

64

What is the treatment of choice for an edentulous 40-year-old epileptic man who sustains a LeFort I fracture during a seizure

Direct wiring of the zygomaticomaxillary buttresses.

65

When is cranialization required for treatment of frontal sinus fractures

Displaced posterior table fractures with a CSF leak or significantly comminuted posterior table fractures.

66

What are the indications for frontal sinus obliteration in the presence of a fracture

Displaced posterior table fractures with involvement of the nasofrontal duct.

67

What are the absolute indications for open reduction of a condylar fracture

Displacement of the fractured fragments into the middle cranial fossa, inadequate reduction with MMF, lateral extracapsular displacement of the condyle, foreign body (ie, bullet) embedded in the joint.

68

What is the most likely cause of cyclovertical diplopia following repair of a NOE fracture

Disruption of the trochlea.

69

When approaching the frontozygomatic buttress through the hemicoronal incision, how is the temporal branch of the facial nerve avoided

Dissection begins just superficial to the superficial layer of the deep temporal fascia; 2 em above the zygomatic arch, the dissection is carried deep to the superficial layer of the deep temporal fascia.

70

What is the plane of dissection with the Gillies approach

Dissection is carried out between the temporalis muscle and its overlying fascia.

71

What are the only plates that can bear the stress of mastication during healing

Eccentric dynamic compression plates.

72

What is the most common complication after orbital reconstruction

Enophthalmos.

73

What is the most helpful test for evaluation of aerodigestive injuries caused by transcervical gunshot wounds

Esophagram with water-soluble contrast agent followed by barium.

74

T/F: Patients with titanium implants cannot undergo MRI

False.

75

What materials can be used to obliterate the frontal sinus

Fat, muscle, fascia, or cancellous bone; can also allow spontaneous osteogenesis after burring the inner cortices.

76

Your patient has a fracture of the mandibular body and a comminuted midface fracture. How do you approach reconstruction

First MMF, then ORlF the mandible, then ORlF the midface.

77

Your patient has a fracture of the condylar head and mandibular body and a comminuted midface fracture. How do you approach reconstruction

First ORIF the midface, then place the patient into MMF, then ORIF the mandibular body fracture.

78

When should lag screws be used to reduce a fracture

For an oblique fracture with an intact inner fragment where the length of the fracture is at least twice the thickness of the bone.

79

When are serial explorations indicated after penetrating injuries to the face

For high-energy gunshot or rifle (> 1200 ft/s) injuries, shotgun injuries, and high-energy avulsion injuries.

80

What test is performed to evaluate for entrapment of the extraocular muscles

Forced duction test.

81

What is brisement force

Forced jaw opening under anesthesia; usually successful for treatment of trismus that does not respond to physiotherapy.

82

What is a class I mandible fracture

Fracture between two teeth.

83

What is a class Ill mandible fracture

Fracture in an edentulous area.

84

What are the absolute indications for surgical repair of frontal sinus fractures

Fractures involving the nasofrontal duct and significantly displaced posterior table fractures with or without dural tear and CSF leak.

85

What are favorable fractures

Fractures where the muscles tend to draw the fragments together.

86

What material is used for grafting

Fresh autogenous particulate marrow.

87

At what ages are deciduous teeth present

From 20 months unti I age 5 - 6.

88

What are the horizontal buttresses of the midface

Frontal bar and cranial base, zygomatic arch and temporal process of the zygoma, maxillary palate and alveolus, and the greater wing and pterygoid plates of the sphenoid.

89

Reduction of which buttresses is essential to restore upper facial width

Frontozygomatic buttresses.

90

Transcatheter arterial embolization is most useful in the management of what type of neck injury

Gunshot wound (GSW) to zone III of the neck.

91

What are the advantages of using cranial bone as an autogenous graft compared to other bone grafts for orbital reconstruction

Harvested from the same surgical field~ little postoperative pain; donor site complications are rare; large amounts can be harvested: less likely to resorb than endochondral grafts.

92

What are the 3 approaches to the frontozygomatic buttress

Hemicoronal, lateral brow, and the upper blepharoplasty incisions.

93

Due to these differences, which facial fractures are more common in children than in adults

High facial fractures (orbital roof, temporal bone fractures).

94

In an adult, what # is the left 3rd molar of the mandible

I 7.

95

A supraclavicular stab wound is in which neck zone

I.

96

When is diplopia likely to persist after orbital reconstruction

If diplopia occurs within 30 degrees of the primary position.

97

What is the optimal treatment for a nondisplaced condylar fracture

If occlusion is normal, soft diet and close observation; bilateral fractures or unilateral fractures with malocclusion should be treated with M M F for 3 weeks, then elastics for 2 weeks.

98

What is the normal inclination of the orbital floor

Inclines superiorly at a 30-degree angle from anterior to posterior and at a 45-degree angle from lateral to medial.

99

What is the most common cause of loss of vision after reduction of facial fractures

Increased intraorbital pressure, usually secondary to venous congestion.

100

What are the sequelae of untreated lateral zygomatic arch fractures

Increased midfacial width and malar flattening.

101

What are the disadvantages of the retroseptal approach

Increased risk of injury to the inferior oblique muscle and prolapse of orbital fat into the surgical field.

102

What are the most common causes of delayed healing and non-union

Infection and noncompliance.

103

The "zone of compression" refers to which area of the mandible

Inferior border of the mandible.

104

What are the contraindications to orbital exploration after orbital trauma

Injury to an only-seeing eye; presence of hyphema, globe injury, or retinal tear; and medical instability.

105

What is a type B ZMC fracture

Injury to each of the 4 supporting structures.

106

What are the treatment options for children between 2 and 5 years of age

Interdental eyelet wiring, arch bars, cap splints, or soft diet.

107

What are the 3 types of condylar fractures

Intracapsular crush fractures of the condylar head, high condylar fractures through the neck above the sigmoid notch, and low subcondylar fractures.

108

Among children, which mandible fractures result in the highest incidence of dentofacial abnormalities

Intracapsular crush fractures of the condyle.

109

What is a type A ZMC fracture

Isolated to one component of the tetrapod structure (zygomatic arch, lateral orbital wall, or inferior orbital rim).

110

Why is the midface inherently prone to deficient projection

It lacks good sagittal buttresses.

111

What is an open bite

Lack of anterior incisal contact when the posterior teeth are in occlusion.

112

What sort of plates should be used in the severely atrophic mandible

Large reconstruction plates.

113

What sort of plates should be used with comminuted mandible fractures

Large reconstruction plates.

114

In cases of panfacial fractures, when should NOE fractures be repaired

Last.

115

What can be done to improve exposure with the transconjunctival approach

Lateral canthotomy with cantholysis.

116

What is the best anatomic guide to reconstruction of the length and medial position of the zygomatic arch

Lateral orbital alignment.

117

On physical exam, the nose and the maxillary alveolar process are found to be free-floating. What type of fracture has occurred

LeFort 11.

118

Which of the LeFort fractures involves the infraorbital rim

LeFort II.

119

What is the major advantage of immediate aggressive reconstruction after a high-energy GSW to the face

Less soft tissue scarring and contracture.

120

What are miniplates

Lightweight, compression-neutral plates designed to be used with self-tapping screws.

121

Which of these is most common

Low subcondylar fracture (often incomplete or "greenstick" injury).

122

What is the most prominent portion of the ZMC

Malar eminence.

123

What are the potential complications from untreated nasofrontal duct fractures

Meningitis. mucopyocele, intracranial abscess.

124

What are the sequelae of untreated maxillary fractures

Midface retrusion, facial elongation, and anterior open bite deformity.

125

What type of screws are used to secure superiorly positioned plates

Monocortical to prevent damage to tooth roots.

126

What are the advantages of the subciliary approach

More direct, requires less understanding of orbital anatomy, and provides more exposure than the transconjunctival approach.

127

What factors lead to infection of mandible fractures

Moving fragments, foreign bodies, dead bone.

128

What are the 3 paired vertical buttresses of the midface

Nasomaxillary, zygomaticomaxillary, and pterygomaxillary.

129

Compared to adults, children are at a higher risk for what type of injury after penetrating injuries to the face and neck

Neurological injury.

130

What are the advantages of using mesh implants for repair of orbital floor fractures

No need for a bone or fascial barrier between the orbital contents and the mesh; posterior orbital shape can be simulated more easily than with bone grafts; well tolerated when exposed to open paranasal sinuses; may facilitate survival of bone grafts in the anterior orbit.

131

What are the advantages of the Gillies approach

No visible scar, protects the temporal branch of the facial nerve, and allows bimanual reduction.

132

What sort of neurologic sequelae usually result from isolated unilateral vertebral artery injury

None.

133

4 weeks after ORIF of a mandibular body fracture, your patients presents with an exposed plate and purulent drainage. The reduction is grossly intact. What do you do

Open wound, remove involved tooth if applicable, remove hardware, and assess union; if nonunion is present, most patients will heal with MMF; other option is plate and bone graft (external approach).

134

10 days after ORIF of a mandibular body fracture, your patient presents with an exposed plate and purulent drainage. The reduction is grossly intact. What do you do

Open wound, remove involved tooth if applicable; if hardware is loose, replace it with a new plate; if hardware is rigid, continue drainage, wound care.

135

What is the weakest part of the entire ZMC complex

Orbital floor.

136

What would be the optimal treatment for a 25-year-old man with a LeFort I fracture, bilateral dislocated subcondylar fractures, and a comminuted left parasymphyseal fracture

ORIF of the parasymphyseal fracture, ORIF of one subcondylar fracture, and MMF for 3 weeks.

137

What is the preferred donor site for bone grafting in the repair of NOE fractures

Outer or inner table of the parietal skull.

138

What is the difference between overbite and overjet

Overbite occurs in the vertical plane whereas overjet occurs in the horizontal plane.

139

What problem may arise in the edentulous, denture-wearing patient after mandible fracture with mental nerve disruption

Patients who wear a complete mandibular denture require gingival sensation; in the presence of bilateral mental nerve paresthesia, it may be impossible for the patient to tolerate a mandibular denture.

140

In patients with mandible fractures, what mechanisms of injury are most predictive of an associated cervical spine injury

Penetrating high-velocity gunshot injury; high-velocity MV A.

141

What makes up the superior portion of the bony nasal septum

Perpendicular plate of the ethmoid.

142

What is the most effective treatment for entropion that fails to resolve with massage

Placement of a spreader graft (ie, palatal mucosal graft) in the posterior lamella.

143

What is the most common cause of infection after ORlF

Poor plating technique.

144

Where should the point of attachment of the medial canthal tendons be directed

Posterior and superior to the lacrimal fossa to avoid telecanthus and blunting of the medial canthal area.

145

Which table of the frontal sinus is thinner

Posterior.

146

What is the appropriate management for a deep puncture wound from a dog or cat bite

Post-exposure rabies prophylaxis should be considered for all bites. If the animal is healthy, it should be quarantined for I 0 days to exclude rabies. If the animal is unavailable or suspected rabid, immediate vaccination and immunoglobulin therapy should be administered. In addition, antibiotic coverage to include Pasteurella multocida, should be initiated.

147

What are the 2 transconjunctival approaches

Preseptal and retroseptal.

148

Which teeth can be used in children between the ages of 7 and 1 1 for immobilization

Primary molars and incisors.

149

What are the advantages to the preseptal approach

Protection of the inferior oblique muscle and periorbita.

150

What is the most sensitive test to detect optic nerve injury after facial trauma

Pupillary reaction to light.

151

How is stabilization by splinting performed

Reconstruction plates with bicortical screws.

152

What is the treatment for infected extraoral mandibular ORI F

Removal of the tooth and the failed plate, debridement of dead bone, placement of a large reconstruction plate, and primary grafting if inadequate bone contact exists.

153

How can one repair a floating palate when the anterior and lateral walls of the maxilla are severely comminuted

Replace the comminuted bone with a bone graft fixed to the alveolar ridge and infraorbital rim.

154

Which of these involves an incision in the fornix directly into the orbital fat

Retroseptal.

155

What are the advantages of using Medpor over other alloplastic materials for orbital reconstruction

Semi-rigid; porous allowing fibrous, vascular, and bony ingrowth; minimal inflammatory reaction; infection and extrusion are rare.

156

What is a type Ill NOE fracture as described by Markovitz et al

Severely comminuted fracture with disruption of the medial canthal tendon or too small of a central fragment to be repaired directly.

157

What is a type I NOE fracture as described by Markovitz et al

Single, noncomminuted central segment fracture.

158

What is the primary disadvantage to the preseptal approach

Slightly higher risk of lower-lid entropion.

159

What is the usual treatment of condylar fractures in children

Soft diet.

160

In a child, what is the treatment for an incomplete monocortical crack of the mandibular body with normal occlusion and movement

Soft diet.

161

Why are fractures of all 4 segments called "tripod" and not "tetrapod" fractures

Some consider the medial attachment to the maxilla and the deep attachment to the sphenoid bone as a single unit.

162

What are the approaches to ORIF of condylar fractures

Submandibular or retromandibular (most common); intraoral; preauricular face lift • • • InCISIOn.

163

Which radiographic view is best for visualizing the zygomatic arches

Submental vertex.

164

What are the 4 bony attachments to the skull radiating from the malar eminence

Superior attachment to the frontal bone (frontozygomatic suture); medial attachment to the maxilla (zygomaticomaxillary suture); lateral attachment to the temporal bone (zygomaticotemporal suture); and a deep attachment to the greater wing of the sphenoid (zygomaticosphenoidal suture).

165

The "zone of tension" refers to which area of the mandible

Superior border of the mandible.

166

Which of these covers the lacrimal fossa

Superior limb.

167

What are the horizontal buttresses of the nasoethmoidal region

Superiorly, the frontal bone and bilateral superior orbital rims; inferiorly, the bilateral inferior orbital rims.

168

A patient presents to you with TMJ ankylosis after repair of a condylar fracture. What should be done

Surgical correction ( interpositional arthroplasty, costochondral grafting, total joint prosthesis) followed by vigorous physical therapy.

169

What is a class II mandible fracture

Teeth are present on only one side of the fracture.

170

What are the indications for extraction of teeth in mandibular fracture lines

Teeth that are grossly mobile, have fractured roots, have advanced dental caries and periapical pathology, have soft-tissue pathology, or that hinder fracture reduction.

171

What determines the projection of the upper face

The frontal bar (supraorbital rims and frontal sinuses).

172

Which part of the lacrimal system is most vulnerable to injury

The inferior canaliculus near the medial canthal tendon.

173

What is an anterior crossbite

The maxillary incisors are lingual to the mandibular incisors.

174

What is a posterior crossbite

The maxillary or mandibular posterior teeth are either buccal or lingual to normal.

175

What is class III occlusion

The mesiobuccal cusp of the 1st maxillary molar lies posterior to the mesiobuccal groove of the mandibular 1st molar.

176

What is class II occlusion

The mesiobuccal cusp of the maxillary 1st molar lies anterior to the mesiobuccal groove of the mandibular I st molar.

177

What is class I occlusion

The mesiobuccal cusp of the maxillary I st molar articulates with the mesiobuccal groove of the mandibular I st molar.

178

What is the significance of the canals of Breschet

The mucosa lining these canals can be a potential origin for mucocele formation.

179

What does survival of a free fat graft in the frontal sinus depend on

The number of transferred pre-adipocytes.

180

What are the vertical buttresses of the nasoethmoidal region

The paired.. central fragments" arising from the frontal process of the maxilla and internal angular process of the frontal bone.

181

After MMF for a condylar fracture, your patient complains of deviation of his jaw on opening. What should be done

The patient should look in the mirror while opening the jaw and practice forcing himself to open without deviation. The deviation can be overcome with these • exerctses.

182

How is closed reduction achieved in edentulous patients

The patient's dentures are wired to his or her jaws using circummandibular and circumzygomatic wires or screws. Gunning splints are used if dentures are not available.

183

What is the difference in tooth viability when comparing plates versus wires for fixation of mandible fractures

There is a significant increase in the nonviability of teeth in the line and adjacent to fractures of the mandible treated by plates compared to those treated with • wtres.

184

Which plating material has been shown to have significantly less streak artifacts on CT scans

Titanium (as compared to stainless steel and vitallium).

185

Which approach to the inferior orbital rim involves cutting the capsulopalpebral fascia

Transcon j unctival.

186

What are the 3 approaches to the inferior orbital rim/orbital floor

Transconjunctival, subciliary, and rim incisions.

187

What is the most common cranial nerve injury after low-velocity GSW to the paranasal sinuses

Trigeminal nerve.

188

What is the indication for reduction of coronoid process fractures

Trismus secondary to impingement of the fractured fragment on the zygoma.

189

T/F: The medial pterygoid muscle elevates the jaw

True.

190

T/F: After mental nerve injury, sensation usually returns even without repair

True.

191

T/F: A mandible fracture in a child is much more likely to be associated with other injuries than in an adult

True.

192

What does "dynamic compression" refer to

Two-plate system (compression and tension plates).

193

Which of these is least common

Type A.

194

How does Markovitz's classification assist with management

Type I fractures usually can be repaired with microplates; type II fractures usually require transnasal wires in addition to plate fixation; type III fractures usually require at least 2 sets of transnasal wires and may require bone grafting.

195

On physical examination, digital pressure on the nasal tip causes prolapse of the distal nose into the pyriform aperture. Which type of NOE fracture is this according to Gruss' classification of NOE injuries

Type II

196

What is the most appropriate approach for exposure of the inferior maxillary buttresses

Upper labial buccal sulcus incision.

197

What is the significance of the presence of a CSF leak when assessing a patient with a frontal sinus fracture

Usually associated with a displaced posterior table fracture and a dural tear.

198

Where is the opening of the nasofrontal duct in the frontal sinus

Usually in the posteromedial floor of the sinus.

199

What are the indications for surgical exploration after ZMC injury

Visual compromise, EOM entrapment, globe displacement, significant orbital floor disruption, displaced or comminuted fractures.

200

After carotid artery injury, when is it too late to attempt revascularization

When coma has occurred beyond 3 hours, if an anemic infarction has occurred, or if no vascular back flow is present.

201

When is stabilization by splinting performed

When compression is impossible ( eg, inadequate fracture surface area, atrophic edentulous fractures, comminuted fractures, and defect fractures).

202

When are bone grafts used in the repair of anterior table fractures

When gaps > 4 - 5 mm are present.

203

After high-energy avulsion injuries to the face, when is reconstruction of missing bone and soft tissue initiated

When no further necrosis is seen at reexploration of the wound.

204

When can bicortical plates be used in children

When permanent dentition is present.

205

What are the indications for open reduction of condylar fractures in children

When the fractured condyle directly interferes with jaw movement; when the fracture reduces the height of the ramus and results in an open-bite deformity; when the condyle is dislocated into the middle cranial fossa.

206

What are the advantages of using miniplates over wires in reducing fractures of the ZMC

Wires only stabilize in the x plane whereas miniplates add stabilization in all 3 spatial planes (x, y, z); wires are difticult to place in free-floating pieces of bone; wires require exposure of the deep surface of the bone.

207

What is the difference in the mechanism of healing between fractures repaired with MMF and fractures repaired with ORIF

With MMF, a callus, formed via micromovement of the fractured ends, bridges the fractured ends together; with ORIF, no callus is formed, and the fracture heals via direct bone growth.

208

Which of these is strongest

Zygomaticofrontal buttress.

209

Reduction of which buttresses is essential to restore the midfacial length

Zygomaticomaxillary and nasomaxillary buttresses.