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MANDIBLE FRACTURES

Overview
As the second most common facial fracture behind nasal bone fractures, the basics of the workup and management of mandible fractures must be understood by the junior otolaryngology resident early in training. Mandible fractures are commonly classified according to their anatomic location: condyle/subcondyle, coronoid, ramus, angle, body, parasymphysis, symphysis, and alveolus. Appropriate management reduces long-term morbidity from these injuries, which can include malocclusion, trismus, infection, nerve injuries, TMJ ankylosis, malunion/nonunion, and dental injuries. Initial exam should focus on airway status as, while relatively rare, bilateral body fractures or other concomitant injuries can lead to acute airway obstruction. The overlying soft tissue should be examined closely for associated injuries and crepitus with documentation of patient reported occlusion and inferior alveolar nerve anesthesia if present. Detailed intraoral exam is crucial including dental health, missing or fractured teeth, occlusion class, and any intraoral lacerations. Non-contrast maxillofacial CT is used in most centers for diagnosis due to availability, high sensitivity, and ability to detect additional facial injuries though panoramic films can be helpful at times for increased visualization of dental fractures, root health, and alveolar ridge details. The favorability of fractures may also be used to classify the fracture and influence the treatment approach. This guide is meant to aid in the initial evaluation of these patients, the AO surgical reference available online (https://surgeryreference.aofoundation.org/cmf/trauma) provides an excellent review of management techniques according to particular subsites of the mandible.

Determining Favorability of a Fracture
Discussions about favorability are largely related to angle and body fractures. Favorability is evaluated in both the horizontal and vertical dimensions. When a fracture is considered favorable, the muscles attached to the mandible are holding the fracture into anatomic reduction (often contracting perpendicular to the fracture line). Generally speaking, the origin and attachment of the musculature on the mandible pull the anterior fragments inferior and posterior (digastrics, genioglossus, geniohyoid, mylohoid), while posterior mandibular fragments are pulled superior and medial (masseter, medial pterygoid, temporalis). A quick method of remembering favorable vs unfavorable fracture patterns is: when viewed in a sagittal or axial plane unfavorable fractures “stink” – that is they point toward the nose.

Occlusion and Dental Numbering
Determining the occlusive status is crucial both in the initial exam as well as during management.  This begins with careful examination of the cuspal interdigitation as well as the location and contact of the wear facets. Normally the maxillary arch of dentition is outside of the mandibular arch. The anterior sextant of maxillary dentition is also wider than the mandibular dentition. Angle’s classification divides occlusive relationship of the maxillary and mandibular teeth into three categories based on the 1st molar relationship. Angle Class I (normal occlusion) indicates that the mesiobuccal cusp (anterior/lateral cusp) of the maxillary 1st molar interdigitates with buccal groove of first mandibular molar. Even with Class I occlusion, malposed teeth or other discrepancies may still exist. In class II malocclusion (or retrognathism), the maxillary 1st molar mesiobuccal cusp is more mesial (anterior) to the buccal groove. Class III malocclusion (prognathism) the cusp is more distal (posterior).  In additional to the class of occlusion, evaluate for premature contact, open bite, cross bite (maxillary buccal cusps fall lingual to the mandibular) and chin deviation.  Subcondylar fractures tend to cause shortening of the mandible with early contact of molars leaving an anterior open bite. Fractured or dislocated teeth or alveolar ridge fractures may also lead to early contact and open bite. During the examination, it is beneficial to ask patient how their occlusion feels as subjective reporting is usually accurate. The universal dental numbering system begins with the right maxillary third molar as tooth #1, tooth 16 is the left maxillary 3rd molar, it then drops to left mandibular 3rd molar for tooth 17 and finishes with right mandibular 3rd molar as tooth 32.

Unique Patient Considerations

  • Pediatric Patients

    • Unerupted teeth lead to areas of weakness in the pediatric mandible and along with future mandibular growth complicate screw and plate placement if open reduction is to be attempted. Fortunately, most pediatric fractures can be managed with soft diet and observation or closed reduction with orthodontic brackets with guiding elastics for MMF. If severe comminution or displacement is present, open fixation or rigid closed reduction may be necessary. When open reduction is required, inferiorly placed monocortical screws and absorbable plates are frequently used. Early mobilization remains paramount for all pediatric patients to prevent TMJ ankylosis and resultant facial height asymmetry  

  • Edentulous Patients

    • Edentulous patients present a unique challenge due to inability to set occlusion and mandibular atrophy that is commonly present. If the patient has dentures, they may aid in judging the occlusion and proper reduction and may be used as a splint to attempt management with closed reduction. Open reduction internal fixation after anatomic reduction is most commonly used to repair mandible fractures in edentulous patients    

Key Supplies for Mandible Fracture Consultation

  • Appropriate PPE including masks, eye protection, gloves, gown

  • Headlight

  • Tongue Depressors

  • Flexible Endoscope

  • Antifog solution (Fred)

Management

  • Ensure no acute airway concerns

  • Full history with attention to mechanism of injury, past medical history, surgical history, personal or family history of problems with anesthesia, and timing of last meal (if planning for OR same day)

  • Detailed head and neck physical exam always starting with ABC’s, cranial nerve exam with documentation of inferior alveolar nerve anesthesia, low threshold for nasopharyngeal endoscopic airway exam, intraoral exam including state of dentition and occlusion, inspect for floor of mouth hematoma

  • Recommend basic labs including CBC, CMP, consider coagulation panel if planning for surgery

  • Imaging

    • Non-contrast maxillofacial CT is preferred in most cases, highly sensitive and allows for 3D recons (helpful if severely displaced or comminuted, may need to call radiology to ask for 3D formatting), preferred in ED setting especially if concerns of additional facial or intracranial injuries

    • Panoramic Films have advantage over CT of improved alveolar ridge and dental details but less sensitivity for fracture identification and do not show condylar malposition as well as CT

    • Mandibular series plain films with Townes view are of historical relevance and may be encountered internationally but are rarely used in U.S

    • For patients with missing teeth that lost consciousness consider chest X-ray to rule out aspiration

  • Surgical timing whether ORIF or closed reduction is generally non-emergent and can be delayed and completed in the morning or within a few days as an outpatient. Delaying increases patient discomfort and there appears to be a gradual trend toward increased infection if delayed beyond a few days.  If a delay in treatment is anticipated, temporary stabilization of a fracture with Ivy loops or circumdental wires is an easy step to reduce fracture bleeding and improve patient comfort

  • Antibiotics to cover oral flora in select cases, in adults most commonly amoxicillin-clavulanate, ampicillin-sulbactam or clindamycin for penicillin allergic patients

  • Start antibiotics with continuation through surgery for open fractures (fracture through tooth bearing mandible is considered open in most cases even if no laceration through skin or mucosa)

  • Intraoperative antibiotics are routine in all cases

  • Postoperative antibiotics typically reserved for cases with severe comminution, contamination or “dirty” mechanism of injury such as gun shot

  • Consider tetanus prophylaxis for contaminated wounds

  • Keep patient NPO if surgery is planned for same day

  • Admission if plan for immediate surgery, if pain is uncontrollable, or if any airway concerns, otherwise may discharge to home

  • If discharging with plan for surgery in following days: start no chew diet, chlorhexidine oral rinse after each meal, ice to jaw 20min/hr while awake, and analgesics

 

General Management Strategies by Subsites
For More Detailed Information, Visit AO: https://surgeryreference.aofoundation.org/cmf/trauma

  •  The first step in ensuring appropriate reduction for any approach is establishing at least temporary rigid fixation of normal occlusion using maxillomandibular fixation (Erich arch bars, IMF screws or hybrid systems) or interdental fixation

  • Parasymphysis/symphysis: ORIF with intraoral approach, two mini plates or two lag screws (consider submental approach)

  • Alveolar ridge: stabilize segment with arch bars or interdental wiring and follow up with endodontist

  • Body: intraoral approach, often with percutaneous screw placement, options include rigid fixation with two miniplates, inferior bicortical plate and superior border monocortical tension-band plate

  • Angle: rigid MMF for 6 weeks or ORIF with transoral placement of a Champy plate (may still need MMF), single mini-plate along superior border, two mini-plates or strut/ladder plate, For displaced or trigone fractures with bone loss, consider external approach with inferior border recon plate

  • Ramus: MMF for 6 weeks, if open is required external approach or intraoral with trocar

  • Subcondylar/Condylar: “closed reduction” with short duration (around 2 weeks) of rigid MMF transitioning to elastics and early mobilization. Absolute indications for ORIF  (Kent and Zide) are:  (1) condyle displaced into the external auditory canal or the middle cranial fossa, (2) foreign body or open temporomandibular joint, (3) inability to obtain occlusion/MMF (4) lateral extracapsular displacement of the condyle. Relative indications include ability to achieve reduction, bilateral fractures, other contraindications for MMF.  ORIF usually requires pre-auricular, submandibular or combined approaches with trans-parotid dissection (consider nerve monitoring) vs endoscopic trans-oral approach with percutaneous access

  • Coronoid: observation, soft diet

 
General Management of Involved Dentition

  • Avulsed tooth

    • Place in milk- replace in socket as soon as possible (unlikely to survive if out > 2 hours) and splint in place with buddy wire or resin acrylic

    • Follow up with dentist or endodontists within 2 weeks usually for root canal

  • Displaced or mobile tooth

    • Document mobility with the Miller Classification: class 1 <1mm horizontal mobility, class II >1mm horizontal mobility, class III >1mm horizontal movement and vertical mobility

    • Reposition and splint with acrylic resin or buddy wire

  • Indications for dental extraction

    • Tooth preventing mandibular fracture reduction

    • Infected tooth within fracture line

    • Tooth fracture with exposed pulp (though some fractured teeth with exposed pulp may be viable in young patients, consider dental evaluation prior to extraction if possible)

    • Tooth within fracture line interfering with occlusion

  • Follow up with dentist for all dental injuries

  • See the Guidelines for the Management of Traumatic Dental Injuries by the AAPD referenced below for more comprehensive management

References:

  1.  Cienfuegos, R., et al. “Mandible”. AO Foundation Surgery Reference, https://surgeryreference.aofoundation.org/cmf/trauma/mandible

  2. DiAngelis AJ, Andreasen JO, Ebeleseder KA. Guidelines for the Management of Traumatic Dental Injuries: 1. Fractures and Luxations of Permanent Teeth. Dent Traumatol 2012;28:2-12.

  3. Miles, B.A., Smith, J.E. (2013). Mandibular Fractures. In J.J. Johnson, C.A. Rosen. (Eds.), Bailey’s Head and Neck Surgery-Otolaryngology 5e (pp. 1195-1208). Baltimore, MD: Lippincott Williams & Wilkins.

  4. Kellman, R.M. (2020). Maxillofacial Trauma. In Flint, P.W., et al (Eds.), Cummings Otolaryngology Head and Neck Surgery 7e (pp. 286-310). Philadelphia, PA: Elsevier.