Mandible Fractures Flashcards
2.1 Description of mandible fracture
2.1 malocclusion with anterior open bite
2.2.1 On H&P, I would first pay attention to
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.
Following attention to the ABCs, I would look for
concomitant, potentially life-threatening injuries, as mandibular fractures can be repaired electively, within 14 days of injury
On exam I would palpate/manipulate for
step-offs and instability
After palpating and manipulating, I would assess mobility and occlusion
Mobility - ability to open and close the mouth, and deviation of the mandible on movement
Occlusion - evaluate based on wear facets of teeth
After assessing mobility and occlusion, I would assess dentition
Edentulous patients have decreased bone stock and require more aggressive procedures for bone fixation
On exam, I would perform a neurologic exam
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
In evaluation of mandibular fractures, I would assess for concomitant facial fractures because these may
alter occlusion
I would obtain a high-resolution maxillofacial CT
the gold standard for imaging
3D reconstruction may further assist in evaluating the injury
If CT is unavailable, I would obtain
a panorex - which allows visualization of the entire mandible and dentition
mandible series - AP, lateral, oblique, and open-mouth reverse Towne view
A panorex allows limited evaluation at
the symphysis and condyles
-additional Towne view improves visualization of subcondylar regions
In the ED, I would begin management with
- oral chlorhexidine rinse to decrease oral flora/bacterial count
- bridle wire placement to help with temporary stability of unstable fractures
I would perform definitive treatment within
2 weeks, as longer delay increases the risk for infection and need for osteotomies
If a mandible fracture is non-displaced and stable
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.
If a mandible fracture is non-displaced with mild instability
I would treat with maxillomandibular fixation (MMF)
What are the 2 types of maxillomandibular fixation (MMF):
Arch bars
Intermaxillary fixation (IMF) screws
-both require appropriate dentition
How long is MMF maintained for the different fracture patterns?
Subcondylar - 2 weeks with early return of motion using guiding elastics
Body/angle - 4 weeks
(Para)symphyseal - 6 weeks
If a mandible fracture is displaced, it requires
open reduction/internal fixation (ORIF)
Steps in ORIF of displaced mandible fractures:
- wide exposure of fractures
- establish occlusion with MMF
- plate fractures
- release MMF to confirm normal occlusion with condyles seated in the temporomandibular joint
- reestablish MMMF
Preferred approach for ORIF of comminuted mandible fractures
transfacial - allows for increased visualization and access to all mandibular surfaces
In plating a mandibular fracture
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
Mildly displaced subcondylar/ramus fractures are preferentially treated with
closed methods - MMF with early release and elastic guidance - as muscular forces and proprioception compensate for architectural deformities
Indications for ORIF of subcondylar/ramus fractures include:
- condylar head displacement into the middle cranial fossa
- foreign body lodged in TMJ
- bilateral subcondylar fractures, resulting in an anterior open bite
Preferred approaches for ORIF of subcondylar/ramus fractures:
retromandibular - allows for good fracture exposure and ease of plating
submandibular (Risdon)
Mandible angle fractures require
ORIF, with removal of 3rd molar if it interferes with reduction
Non-comminuted mandible angle fractures may be treated with
- 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
Comminuted mandible angle fractures are best treated with
a Risdon (submandibular) approach
Mandible body fractures require
ORIF
Most mandible body fractures may be approached with
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)
Comminuted mandible body fractures may be approached with
a Risdon approach as this allows for wide access
Mandible (para)symphyseal fractures require
ORIF given their inherent instability
Approach useful for most mandible para(symphyseal) fractures
intraoral approach - as it provides excellent exposure, permitting continuous visual assessment of occlusion, without external scars
Approach useful for comminuted mandible para(symphyseal) fractures
extraoral (submental) approach
Before completion of repair of a mandible para(symphyseal) fracture
the patient must be examined with MMF released, confirming normal occlusion with the condyles firmly seated in the TMJ fossa
If after mandible repair MMF released and normal occlusion with the condyles firmly seated in the TMJ fossa is not confirmed, then
the plates must be released and the fracture re-reduced
Endentulous mandibles are prone to
malunion due to limited bone stock
Endentulous mandibles with a height of < 10 mm are best treated with
ORIF with large plate and immediate bone grafting
Endentulous mandibles require
more aggressive treatment via an external approach and fixation with large reconstruction plates to provide long-term stability
An alternative to plate fixation in edentulous mandibles is
Gunning splint ot wiring in current dentures, but this provides less stability than an open approach
Complication: malocclusion
-best avoided by confirming adequate occlusion before completion of the procedure
Complication: malunion/nonunion
-may require debridement and bone grafting
Complication: infection
-avoid urge to remove plates until fracture is healed, as early removal will result in malocclusion
Complication: damage to inferior alveolar nerve
-best avoided by keeping hardware away from midportion of mandible where nerve courses
