Fractures with dentoalveolar involvement are considered open fractures as—even in nondisplaced fractures—there is communication between the oral cavity and mandibular marrow space through the periodontal pockets around the affected teeth. This is especially true of fractures of the mandibular angle: here the fracture line typically travels through the periodontal pocket of the distal root of the last molar, continuing through the socket of the frequently unerupted wisdom tooth. In edentulous portions of the mandible, there are often also lacerations of the mucosa firmly attached to the bone (attached gingiva). Management of these fractures must therefore occur expeditiously, in order to minimize the risk of infection in the fracture gap.

Fractures of the mandible including the angle and ramus of mandible to the height of the mandibular foramen are managed using osteosynthesis techniques. The technique of choice is the placement of miniplates, which are fixed using monocortical screws to prevent injury to the roots of the teeth and inferior alveolar nerve. In isolated instances, compression plating (for infected fractures) is used. Fixation is with bicortical screws placed so as to avoid damaging the roots of the teeth or inferior alveolar nerve.

An intraoral approach is used to access the fracture. Correct occlusion must be established for surgery. To do so, the upper and lower jaws are splinted and intermaxillary immobilization is placed during the operation. Teeth in the line of fracture can impede fragment realignment or even render it impossible, and they can cause infection at the fracture gap. The indication for retaining teeth in the line of fracture is thus very narrowly assessed.

Simple mandibular fractures can be managed with the patient under local anesthesia. Treatment under intubation anesthesia is generally the preferred method. For restoration of occlusion, endonasal or submandibular intubation is necessary.

As a general rule, an intraoral approach is used for surgical access to the mandibular body and ramus to the height of the semilunar notch. After injection of a vasoconstrictor for intraoperative hemostasis (local anesthesia with epinephrine 1:100 000), the oral vestibule is opened using suitable retractors.

Fig. 21.1 Conservative management of a slightly displaced atypical comminuted mandibular fracture with splinting and intermaxillary immobilization.

a Clinical picture after splinting and intermaxillary immobilization.

b Orthopantomogram prior to treatment.

c After splinting and intermaxillary immobilization.

Fractures involving the symphyseal region are stabilized using two four-hole or six-hole miniplates. One miniplate is placed just caudal to the root tips of the frontal incisors or canines, and the other further to caudal 5 mm cranial to the mandibular margin. Selecting the correct screw length (7 mm) can ensure that damage to the roots of the teeth is avoided.

Fig. 21.3 Placement of four-hole miniplates for osteosynthesis in an oblique mandibular fracture in the right canine tooth region.

a Clinical picture.

b Orthopantomogram.

Fig. 21.2 Vestibular incision (modified from Kellman and Marentette 1995).

a Incision slightly towards buccal from the vestibule. Alternatively, a gingival margin incision can be used.

b Subperiosteal dissection of the mandible.

c Exposure and preservation of both mental nerves. Incising the periosteum over the nerve makes exposure easier.

Fig. 21.4 Fracture of the right mandibular angle.

a Proper fragment position after placing a six-hole miniplate.

b Properly healed fracture after removing osteosynthesis materials.

Fig. 21.5 Plate osteosynthesis of an infected fracture of the right mandibular angle using a compression plate on the basal margin of the mandible and a miniplate on the temporal crest (tension banding).

Injury to the mental nerve;

Injury to the inferior alveolar nerve in the bony canal;

Hemorrhage in the floor of the mouth from vascular injury;

Injury to the roots of the teeth;

Unstable osteosynthesis;

Soft tissue trauma from hook traction;

Hematomas from insufficient drainage increase the risk of wound infection.

Nondisplaced fractures of the mandibular ramus can be treated conservatively with splinting of the upper and lower jaws and intermaxillary fixation for a period of 4– 6 weeks.

Surgical management of displaced mandibular ramus fractures has advantages, as it offers the only means of correct fragment positioning.

Access is intraoral. The mucosal incision is placed over the anterior margin of the mandibular ramus and is carried from there into the oral vestibule. The fracture can be exposed after freeing the periosteum from the mandible.

The upper and lower jaws are splinted and intermaxillary immobilization is established. After exposing the fracture, it is reduced and stabilized using miniplates with the jaws in proper occlusion and fragments correctly positioned. Wound drainage is with a Redon drain. The wound is closed using suture materials that are impermeable to oral fluids.

Inadequate drainage can result in postoperative hematomas or infections.

Fracture reduction is difficult because the narrow surgical approach often fails to provide depth perception in the fracture gap region.

Dentition and, in particular, secured occlusion, have an important stabilizing influence on fragments in the healing of mandibular fractures. The edentulous mandible is frequently atrophied and occasionally no thicker than a pencil. Cancellous bone is lacking and the bone is sclerotic and poorly vascularized. Surface contact areas are small in the fracture region. Protracted fracture healing and an increased rate of complications (osteitis of the fracture gap, pseudarthrosis) are therefore to be expected.

Without exception, fractures of the edentulous or inadequately dentate jaw must thus be managed with miniplates or compression plates. In the extremely atrophied jaw, compression plating is the superior technique, despite low bone mass. An extraoral approach is preferred in such situations.

Fig. 21.6 Osteosynthesis in a mandibular fracture of an atrophied jaw.

a Fracture in the left molar region (arrows).

b Stabilization with a four-hole compression plate from extraoral—correct fragment position.

c Twelve months post trauma and after removing osteosynthesis materials—normal knitting together of bones at the fracture gap.

In mandibular defect fractures (missile wound), one must consider whether:

primary reconstruction of the mandible should be with autogenous, possibly microvascular pedicled bone transfer, bone/muscle, or bone/muscle/skin grafting (fibula, scapula, iliac crest) or;

whether the mandibular stumps should be stabilized initially using a reconstruction plate for bridging mandibular defects so as to avoid irreversible warping and atrophy of soft tissues caused by scarring.

Fig. 21.7 Mandibular defect fractures.

a Mandibular defect fracture after osteomyelitis at the fracture gap.

b Fracture management with splinting, intermaxillary immobilization, autogenous cancellous bone grafting from the iliac crest, and compression plating.

An infected, untreated fracture should be viewed as a defect fracture and stabilized using a rigid plate (compression plate). In some situations, immediate bone grafting is indicated. It is imperative that the screws fixing the plates are inserted into healthy bone and not in tissue with inflammatory changes. Compression plating is in such circumstances preferable to miniplating.

Fig. 21.8 Pediatric mandibular fracture.

a Osteosynthesis of a mandibular fracture in a child. The four-hole miniplate was placed with short screws (5 mm) on the basilar arch to avoid damage to the tooth germs with certainty.

b Splinting of upper and lower jaws in conservative management of a pediatric mandibular body fracture.

All fractures of the mandibular neck or condyle require management. The goal of treatment is undisturbed joint functioning and healing of bones in proper fragment position. Posttraumatic displacement caused by muscular pulling forces or mouth opening movements should be prevented. Immobilization of the mandible and the temporomandibular joint in particular, eases pain and accelerates subsidence of swelling. Treatment can be conservative, surgical, or functional. Often, a combination of treatment approaches is advisable. If various courses of treatment are possible, the patient must be thoroughly informed of the advantages and disadvantages of each procedure.

If the patient rejects or cannot tolerate intermaxillary immobilization, and if pure functional treatment appears inadequate, surgical management should be considered for the treatment of nondisplaced fractures of the condylar process. It can occasionally be considered for edentulous patients as well. For concomitant fractures of the facial skeleton, surgery allows early mobilization of the mandible.

Operative management of fractures of the condylar process is, as a general rule, performed under intubation anesthesia. Endonasal or submandibular intubation is necessary, as osteosynthesis plating with the jaws in proper occlusion is generally performed with securely wired dental arches. Tracheotomy is not necessary.

Fig. 21.9 Conservative management of a (bilateral) nondisplaced condylar process fracture with splinting and intermaxillary immobilization. Radiographs in two planes (A, B).

The mucosal incision is placed at the temporal crest and is carried from there into the oral vestibule. The mucosa and periosteum are incised. After exposing the mandible to the temporomandibular joint, freeing the masseter muscle, identifying the semilunar notch, and freeing the temporalis muscle attachment from the coronoid process, the fracture of the condylar process is exposed. The periosteum should be stripped from the bone about 1– 2 cm proximal to the fracture for placing the plates. Care must be taken to avoid displacement of the fracture during dissection.

Surgical Technique