Mandible Fractures

Question 1

2.1 Description of mandible fracture

Answer 1

2.1 malocclusion with anterior open bite

Question 2

2.2.1 On H&P, I would first pay attention to

Answer 2

The ABCs - airway, breathing, and circulation.
Given multiple mandible fractures I would pay attention to stability of the airway. Intubation may be required if the patient is unable to protect the airway.

Question 3

Following attention to the ABCs, I would look for

Answer 3

concomitant, potentially life-threatening injuries, as mandibular fractures can be repaired electively, within 14 days of injury

Question 4

On exam I would palpate/manipulate for

Answer 4

step-offs and instability

Question 5

After palpating and manipulating, I would assess mobility and occlusion

Answer 5

Mobility - ability to open and close the mouth, and deviation of the mandible on movement
Occlusion - evaluate based on wear facets of teeth

Question 6

After assessing mobility and occlusion, I would assess dentition

Answer 6

Edentulous patients have decreased bone stock and require more aggressive procedures for bone fixation

Question 7

On exam, I would perform a neurologic exam

Answer 7

Blunt trauma can result in neurapraxic injury of the mental/inferior alveolar nerve, which provides sensation to the lower lip
Marginal mandibular branch of the facial nerve, which innervates the depressors of the lower lip, is rarely injured

Question 8

In evaluation of mandibular fractures, I would assess for concomitant facial fractures because these may

Answer 8

alter occlusion

Question 9

I would obtain a high-resolution maxillofacial CT

Answer 9

the gold standard for imaging

3D reconstruction may further assist in evaluating the injury

Question 10

If CT is unavailable, I would obtain

Answer 10

a panorex - which allows visualization of the entire mandible and dentition
mandible series - AP, lateral, oblique, and open-mouth reverse Towne view

Question 11

A panorex allows limited evaluation at

Answer 11

the symphysis and condyles

-additional Towne view improves visualization of subcondylar regions

Question 12

In the ED, I would begin management with

Answer 12

• oral chlorhexidine rinse to decrease oral flora/bacterial count
• bridle wire placement to help with temporary stability of unstable fractures

Question 13

I would perform definitive treatment within

Answer 13

2 weeks, as longer delay increases the risk for infection and need for osteotomies

Question 14

If a mandible fracture is non-displaced and stable

Answer 14

I would first treat with non-operative management with a soft, non-chew diet for 4 weeks. If there is subsequent instability, I would proceed with operative treatment.

Question 15

If a mandible fracture is non-displaced with mild instability

Answer 15

I would treat with maxillomandibular fixation (MMF)

Question 16

What are the 2 types of maxillomandibular fixation (MMF):

Answer 16

Arch bars
Intermaxillary fixation (IMF) screws
-both require appropriate dentition

Question 17

How long is MMF maintained for the different fracture patterns?

Answer 17

Subcondylar - 2 weeks with early return of motion using guiding elastics
Body/angle - 4 weeks
(Para)symphyseal - 6 weeks

Question 18

If a mandible fracture is displaced, it requires

Answer 18

open reduction/internal fixation (ORIF)

Question 19

Steps in ORIF of displaced mandible fractures:

Answer 19

1. wide exposure of fractures
2. establish occlusion with MMF
3. plate fractures
4. release MMF to confirm normal occlusion with condyles seated in the temporomandibular joint
5. reestablish MMMF

Question 20

Preferred approach for ORIF of comminuted mandible fractures

Answer 20

transfacial - allows for increased visualization and access to all mandibular surfaces

Question 21

In plating a mandibular fracture

Answer 21

stronger plates - are necessary to establish rigid fixation of the inferior border of the mandible
tension bands - in the form of a miniplate just below hte tooth roots or an arch bar anchored to the dentition - are placed superiorly to avoid splaying of the fracture line

Question 22

Mildly displaced subcondylar/ramus fractures are preferentially treated with

Answer 22

closed methods - MMF with early release and elastic guidance - as muscular forces and proprioception compensate for architectural deformities

Question 23

Indications for ORIF of subcondylar/ramus fractures include:

Answer 23

• condylar head displacement into the middle cranial fossa
• foreign body lodged in TMJ
• bilateral subcondylar fractures, resulting in an anterior open bite

Question 24

Preferred approaches for ORIF of subcondylar/ramus fractures:

Answer 24

retromandibular - allows for good fracture exposure and ease of plating
submandibular (Risdon)

Question 25

Mandible angle fractures require

Answer 25

ORIF, with removal of 3rd molar if it interferes with reduction

Question 26

Non-comminuted mandible angle fractures may be treated with

Answer 26

• an intraoral approach w/ percutaneous access for plating along the inferior border
• champy technique with placement of a tension band at the external oblique ridge w/o use of an inferior border plate

Question 27

Comminuted mandible angle fractures are best treated with

Answer 27

a Risdon (submandibular) approach

Question 28

Mandible body fractures require

Answer 28

ORIF

Question 29

Most mandible body fractures may be approached with

Answer 29

an intraoral (vestibular) approach - as this allows excellent visualization of and access to the mandibular body, no external scars, and little risk to vital structures (i.e., marginal mandibular nerve)

Question 30

Comminuted mandible body fractures may be approached with

Answer 30

a Risdon approach as this allows for wide access

Question 31

Mandible (para)symphyseal fractures require

Answer 31

ORIF given their inherent instability

Question 32

Approach useful for most mandible para(symphyseal) fractures

Answer 32

intraoral approach - as it provides excellent exposure, permitting continuous visual assessment of occlusion, without external scars

Question 33

Approach useful for comminuted mandible para(symphyseal) fractures

Answer 33

extraoral (submental) approach

Question 34

Before completion of repair of a mandible para(symphyseal) fracture

Answer 34

the patient must be examined with MMF released, confirming normal occlusion with the condyles firmly seated in the TMJ fossa

Question 35

If after mandible repair MMF released and normal occlusion with the condyles firmly seated in the TMJ fossa is not confirmed, then

Answer 35

the plates must be released and the fracture re-reduced

Question 36

Endentulous mandibles are prone to

Answer 36

malunion due to limited bone stock

Question 37

Endentulous mandibles with a height of < 10 mm are best treated with

Answer 37

ORIF with large plate and immediate bone grafting

Question 38

Endentulous mandibles require

Answer 38

more aggressive treatment via an external approach and fixation with large reconstruction plates to provide long-term stability

Question 39

An alternative to plate fixation in edentulous mandibles is

Answer 39

Gunning splint ot wiring in current dentures, but this provides less stability than an open approach

Question 40

Complication: malocclusion

Answer 40

-best avoided by confirming adequate occlusion before completion of the procedure

Question 41

Complication: malunion/nonunion

Answer 41

-may require debridement and bone grafting

Question 42

Complication: infection

Answer 42

-avoid urge to remove plates until fracture is healed, as early removal will result in malocclusion

Question 43

Complication: damage to inferior alveolar nerve

Answer 43

-best avoided by keeping hardware away from midportion of mandible where nerve courses