What is the treatment for a broken mandible (lower jawbone)?

Treatment of Mandibular Fractures

Immediate Management Priority

Secure the airway first if compromised, particularly with bilateral body fractures or flail mandible, before proceeding with any definitive fracture management. 1

Diagnostic Imaging Requirements

• Obtain CT maxillofacial without contrast as the essential diagnostic modality, achieving nearly 100% sensitivity for detecting all fracture patterns including subtle condylar and subcondylar fractures 2, 3, 1
• CT provides multiplanar and 3-D reconstructions critical for identifying comminution and displacement—both findings that directly alter surgical management 2
• Always search for a second fracture after identifying the first, as 67% of mandibular fractures occur in pairs due to the U-shaped ring configuration of the mandible 1, 4
• Common dual fracture patterns include: mandibular angle/subcondylar fracture with contralateral parasymphyseal fracture, and flail mandible (bilateral subcondylar fractures with symphyseal fracture) 1, 4

Mandatory Associated Injury Screening

• Screen for intracranial injury in all patients, present in approximately 39% of mandibular fracture cases 1, 4
• Evaluate cervical spine injury, occurring in approximately 11% of patients 3, 1, 4
• Assess for inferior alveolar nerve damage when fractures extend through the mandibular canal, which can cause anesthesia of the ipsilateral lower lip, chin, anterior tongue, and mandibular teeth 2
• Approximately 20-40% of patients have additional injuries beyond the mandible 1, 4

Definitive Treatment Approach

Surgical (Open) Reduction and Internal Fixation

Open reduction with internal fixation using miniplates and screws is the primary treatment modality for most displaced mandibular fractures. 5, 6

• Use rigid internal fixation with plates and screws to achieve stable fracture reduction and allow early mobilization 5, 6
• The choice between one miniplate versus two miniplates shows no significant difference in post-operative infection rates (RR 1.32,95% CI 0.41 to 4.22), though evidence quality is limited 5
• Similarly, 3-dimensional (3D) miniplates versus standard 2D miniplates show no difference in infection rates (RR 1.26,95% CI 0.19 to 8.13) 5
• Biodegradable poly-L-lactide plates and screws provide a reliable alternative to titanium systems, with clinical union achieved by 8 weeks in most cases, though mucosal dehiscence occurs in approximately 9% of cases 7, 8

Closed (Non-Surgical) Reduction

• Intermaxillary fixation (IMF) alone may be appropriate for minimally displaced or favorable fractures where surgical access is contraindicated 5, 6
• This approach requires patient compliance and prolonged immobilization 6

External Fixation

• Reserve external fixation for cases with extensive comminution, bone or soft tissue loss, or active infection where open treatment is contraindicated 9
• External fixation can be used temporarily until definitive treatment is delivered 9
• Uniphasic or biphasic systems use surgically placed threaded pins and connectors that can be manipulated to optimize fracture reduction 9

Specific Anatomic Considerations

Condylar and Subcondylar Fractures

• These fractures commonly cause trismus (lockjaw) and require CT for accurate detection, as displacement can be subtle 2, 3
• Do not assume lockjaw is only muscular spasm—it frequently indicates condylar or subcondylar fracture requiring surgical evaluation 3

Angle Fractures

• May be managed with intraoral access alone or combined with transbuccal approach, though evidence comparing these approaches is insufficient 5

Wound Management and Prophylaxis

• Cefuroxime provides adequate coverage for facial wound contamination 3
• NSAIDs (such as mefenamic acid) are appropriate for pain control 3
• Anti-tetanus prophylaxis (ATS/TAT) is indicated for contaminated wounds 3

Critical Pitfalls to Avoid

• Never miss the second fracture—systematically examine the entire mandible on CT after identifying the first fracture 1, 4
• Do not proceed with definitive fracture management before securing the airway in bilateral body fractures or flail mandible 1
• Always screen for associated injuries, as nearly 40% have intracranial injuries and 11% have cervical spine injuries 1, 4
• Avoid relying on panoramic radiography (OPG) alone, as it misses condylar fractures, subcondylar fractures with anterior displacement, and nondisplaced anterior fractures despite 92% sensitivity for simple fractures 3, 4

Evidence Quality Limitations

• Current evidence consists primarily of small randomized trials at high or unclear risk of bias, with inadequate reporting of patient-oriented outcomes and post-operative pain scores 5
• Until higher quality evidence emerges, treatment decisions should be based on fracture pattern, displacement, comminution, and surgeon experience 5, 6
• The lack of definitive evidence supporting one fixation technique over another means that rigid internal fixation with miniplates remains the standard approach, with modifications based on individual fracture characteristics 5, 6