eMedicine Specialties > Otolaryngology and Facial Plastic Surgery > Trauma

Mandibular Angle Fractures: Treatment

Author: Jose E Barrera, MD, Clinical Faculty, Department of Otolaryngology-Head and Neck Surgery, Wilford Hall Medical Center
Coauthor(s): Stephen G Batuello, MD, Consulting Staff, Colorado ENT Specialists
Contributor Information and Disclosures

Updated: Nov 10, 2008

Treatment

Medical Therapy

Patients with isolated nondisplaced or minimally displaced condylar fractures may be treated with analgesics, soft diet, and close observation. Patients with coronoid process fractures may be similarly treated. Additionally, these patients may require mandibular exercises to prevent trismus. If the fractured coronoid restricts mandible movement, medical therapy is contraindicated. Administer prophylactic antibiotics for compound fractures. Penicillin remains the antibiotic of choice.

The techniques for closed reduction and fixation of the dentulous mandible vary. Placement of Ivy loops using 24-gauge wire between 2 stable teeth, with use of a smaller-gauge wire to provide maxillomandibular fixation (MMF) between Ivy loops, has been successful. Arch bars with 24- and 26-gauge wires are versatile and frequently are used. In an edentulous mandible, dentures can be wired to the jaw with circummandibular wires. The maxillary denture can be screwed to the palate. (Any screw from the maxillofacial set can be used as a lag screw.) Arch bars can be placed and intermaxillary fixation (IMF) achieved. Gunning splints have also been used in this scenario because they provide fixation and yet permit food intake. In cases of comminuted fractures, a mandibular reconstruction plate may be required to restore anatomic position and function.

Surgical Therapy

Multiple approaches for open reduction and internal fixation (ORIF) exist. Consider fracture location, nerve position, and skin-crease lines when choosing the appropriate approach.

Intraoral approach

The intraoral approach is usually used in fractures that are nondisplaced or only slightly displaced. The mandible base may require additional stab incisions to place screws for plate fixation. Intraoral lacerations may be used for access in fixation of mandible fractures. Local anesthesia may be sufficient for simple or nondislocated fractures when 1-plate fixation is required.

The minimally invasive fixation of angle fractures has been described.¹ Using a trocar penetration of the masseter at the focus of interest greatly facilitates plate fixation while obviating the need for an additional facial incision. Cole et al reported that trocar excursion within local subcutaneous tissue routinely yields more than 1-2 cm movements.

However, when engaged within the masseteric sling, trocar mobility typically falls to less than 4 mm. By maneuvering the percutaneous trocar within the subcutaneous tissue, rather than within the mesenteric sling as usual, much greater instrument range-of-motion is achieved. Upon review of their 5-year experience with minimally invasive mandible angle repair, this simple refinement significantly decreased operative challenge, improved instrument range-of-motion, and eased the steep learning curve of minimally invasive repair of mandible angle fractures while optimizing aesthetic outcome.¹

External incisions are usually necessary with fractures that have a high degree of dislocation or with comminuted fractures, since placing longer and stronger plates is difficult via the intraoral approach. Although not impossible, reducing and securing angle and ramus fractures are difficult; therefore, these fractures usually require an extraoral approach. General anesthesia is indicated in the extraoral approach. Give careful attention to the marginal mandibular branch of the facial nerve.

Transverse fracture line without displacement

Semirigid fixation using miniplates and monocortical screws may be used in a transverse fracture line with limited exposure.

Although 1-plate fixation is possible using a 2.0 miniplate, the forces that occur during function are usually too great to be neutralized by a single plate.

This fracture is better managed using two 2.0 miniplates (4-6 holes, 2-3 screws on each side), the first in the area of the oblique line and the second at the inferior border (see Image 1). Fixation is also possible using a single lag screw in the anteroposterior-oblique approach in nonosteoporotic bones.

Transverse fracture line with displacement

With dislocation, the medial pterygoid and masseter muscles cause vertically and horizontally unfavorable vector forces, which make reduction more difficult. For a minimally displaced fracture, achieve reduction by fixing a 2.0 miniplate of suitable length to the proximal fragment on the medial aspect of the anterior border of the ramus using 2-3 screws. Reduce the fracture using the plate as a handle to complete IMF. Bend the free end of the plate to conform to the distal oblique ridge and fix with monocortical screws.

A widely displaced fracture may require stabilization by using a reconstruction plate. Following IMF, widely displaced or comminuted angle fractures can be reduced with clamps and stabilized by splinting with a reconstruction plate (ie, 2.4 low-contact dynamic compression plate [LCDCP] at the inferior border, well anchored with 3 screws on each side of the fracture). A 2.0 miniplate may be placed at the oblique line.

No difference in short-term complication rates can be found when comparing 2.0 mm locking plates with 2.0 mm monocortical plates. In a prospective randomized clinical study at Harborview Medical Center, 90 patients with 122 fractures were stratified to 64 treatment sites that received locking plates and 58 sites that received standard plates.² No statistically significant difference was found between the plates used.

Angular fractures with basal triangle

As with displaced fractures, use an angulated 2.4 reconstruction plate with 6-8 holes at the base of the mandible after IMF. The triangle can be fixed to the plate, or lag screws (2.0, 2.4) can be placed. Use a 2.0 miniplate along the oblique line.

Comminuted angular fractures

These often occur in association with other mandibular and maxillary fractures. After temporary IMF, reduction and fixation of fragments within simpler fractures can be accomplished using 1.5 or 2.0 miniplates and lag screws and then bridging with a 2.4 reconstruction plate (see Image 3). Miniplates are often used to reduce large fragments of a comminuted angular fracture. However, miniplates may not be strong enough to bridge severely comminuted fractures.

Comminuted fractures of the ascending mandibular ramus

In the case of concurrent fractures of the ascending ramus, a combined submandibular and preauricular approach may be warranted.

Simplify the fracture using 2.0 miniplates and subsequent bridging and then stabilize it with a 2.4 universal fracture plate or reconstruction plate (see Image 4).

Preoperative Details

Approach mandibular fractures methodically. Patients rarely die solely from mandibular fractures. Diagnose and treat in an efficient manner. As with all trauma patients, strictly adhere to advanced trauma life support (ATLS) protocols. Particular attention to the airway is of critical importance to any patient with craniofacial trauma.

Use prophylactic antibiotics for compound fractures. Penicillin remains the antibiotic of choice. Evaluate nutritional needs.

Intraoperative Details

The goal of treatment is to reestablish occlusion. Function is compromised with malunion. Most mandibular fractures can be treated by closed reduction. Nondisplaced favorable fractures can be managed with closed reduction and IMF alone. Arch bars or Ernst ligatures may be placed and supplemented with an autopolymerizing resin.

The 3 separate techniques for rigid fixation of the mandible that have been developed are (1) the bicortical Luhr system, using vitallium plates, (2) the Arbeitsgemeinschaft für Osteosynthesefragen/Association for the Study of Internal Fixation (AO/ASIF) system of stainless steel compression or reconstruction plates with bicortical screws, and (3) the Champy miniplate technique placed along the line of ideal osteosynthesis, using monocortical screws.

A prospective randomized clinical trial comparing 2.0-mm locking plates to 2.0-mm standard plates in the treatment of mandible fractures found no statistically significant difference between the plates. In addition, mandible fractures treated with 2.0-mm locking plates and 2.0-mm standard plates present similar short-term complication rates.

With multiple facial fractures, usually treat mandibular fractures first, since the mandible is the foundation on which other facial bones may be repaired to restore form and function. Perform intraoral surgery prior to an extraoral approach. IMF time varies according to type, location, number, and severity of fracture(s). Generally, 6 weeks of IMF are prescribed, although this is only an empiric approximation.

Treat dental injuries concurrently with the fracture. Fractured teeth may become infected or jeopardize bone union and should be removed in consultation with a dentist. Mandibular cuspids help determine occlusion and should be preserved if possible.

Respect the third molar in angle fractures. Removal of the third molar is associated with conversion of a closed fracture to an open fracture, loss of the bony buttress on the tension side, and loss of the possibility for a tension band plate. Extract the third molar only when the apex is open to the fracture line, the root is fractured, or the molar is partially erupted.

Postoperative Details

Administer analgesic medications in the postoperative period. Administer antibiotic therapy covering gram-positive organisms to patients with open fractures. Keep wire cutters at the bedside in case of emesis. Reevaluate nutritional needs.

Follow-up

Maintain IMF for 4-6 weeks. Tighten wires every 2 weeks. After wires are removed, a Panorex radiograph is usually taken to ensure complete fracture union.

Complications

Complications following repair of a mandibular fracture are rare.

The most common complication is infection or osteomyelitis. Malunion and nonunion of the mandible occur because of failure to observe treatment goals as previously outlined. Malunion is described as delayed, incomplete, or faulty union following a fracture. More specifically, delayed union is characterized as no clinical evidence of bone union after 8 weeks.

Several factors contribute to malunion, including infection (the greatest factor), injury severity, inadequate reduction, lack of fracture stability, lack of compliance, alcoholism, and metabolic and nutritional deficiencies.

Nonunion describes improperly healed fractures. Nonunion may be due to delay in treatment, inadequate immobilization, and osteomyelitis of the fracture before and after surgery.

Contributing factors include oral sepsis, teeth in the fracture line, alcohol abuse and chronic disease, prolonged time prior to treatment, poor patient compliance, and displacement of fracture fragments.

In addition, plate fracture has been identified as a complication. Material analysis of AO plates used in mandible fractures revealed titanium plate fracture in 4 out of 110 mandibular reconstructions. The plate fracture was most common in angle-type plates due to constriction on the internal side of the plate.

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