The goal of bicortical fixation of mandibular fractures is to provide for undisturbed healing and immobility of fragments to facilitate primary bony union. This type of fixation should provide sufficient rigidity for fracture segments to resist any movement along the fracture line during normal function of the mandible. The decision of which technique to use for fixation of a particular mandible fracture depends on multiple factors, such as fracture location, favorability of fracture vectors, anatomic location of fractures, systemic health of the patient, timing of surgery, experience of the surgeon, age of the patient, and patient compliance. In this chapter, the authors discuss the indications and techniques of bicortical fixation of mandible fractures.
The goal of bicortical fixation of mandibular fractures is to provide for undisturbed healing and immobility of fragments to facilitate primary bony union. This type of fixation should provide sufficient rigidity for fracture segments to resist any movement along the fracture line during normal function of the mandible. The decision of which technique to use for fixation of a particular mandible fracture depends on multiple factors, such as fracture location, favorability of fracture vectors, anatomic location of fractures, systemic health of the patient, timing of surgery, experience of the surgeon, age of the patient, and patient compliance. In this article, the authors discuss the indications and techniques of bicortical fixation of mandible fractures.
Patient assessment
Age and gender are important factors in evaluation and treatment selection for patients with mandible fractures. Younger patients have improved postoperative healing compared with older patients. Many elderly patients have decreased osseous density because of age-related osteopenia or various disease processes. Young men generate greater biting forces than women or elderly patients. Patients with chronic medical conditions, such as epilepsy, psychiatric disorders, and alcoholism, may not tolerate maxillomandibular fixation and may require open reduction with rigid fixation for fracture treatment.
Indications for open reduction and internal fixation of mandibular fractures
Fractures that may require open reduction and internal fixation (ORIF) include open fractures, displaced fractures, severely comminuted fractures, multiple fractures (mandibular fractures in combination with condylar/subcondylar fractures), infected fractures, fractures in medically compromised patients, atrophic mandible fractures in edentulous patients, and patients for whom maxillomandibular fixation is contraindicated. The type of fracture and its location play a primary role in selecting the surgical approach and type of fixation required for proper reduction and stabilization of the fracture. Restoration of proper occlusion should be the primary goal; application of maxillomandibular fixation should be achieved as a first step. In edentulous patients, existing dental prostheses or fabricated splints should be used for proper alignment of the maxilla relative to the mandible. They can be used as an intraoperative guide for rigid fixation or be held in place during the entire bone-healing period.
Fractures located along the ascending ramus and posterior to the second molar are considered mandibular angle fractures. In many cases, these fractures traverse through partially or completely impacted third molars. These types of angle fractures pose several challenges for surgeons. If a third molar is partially impacted or comes into contact with the second molar, the fracture is considered to be an open fracture. Removal of an impacted third molar may displace fracture segments, which could potentially hamper adequate reduction and increase potential for inferior alveolar nerve injury. Angle fractures that require bicortical fixation are significantly displaced and occur in combination with other mandible fractures. Types of approaches and hardware used for fixation of these fractures are dictated by the location, displacement of fracture segments, comminution of fracture segments, position of third molar, and experience of the surgeon. A severely displaced left mandibular angle fracture is demonstrated in Figs. 1 and 2 .
If the fracture line transverses the capsule of the temporomandibular joint, the fracture is considered intracapsular. Intracapsular fractures are treated with short periods of immobilization followed by physical therapy. Fractures below the capsule are condylar neck fractures, which are situated inferior to the capsule. Condylar neck fractures are further subdivided into low and high fractures based on proximity to the capsule. Condylar fractures generally do not require fixation and can be treated conservatively with full liquid diet or short-term maxillomandibular fixation. Subcondylar fractures originate from the area of the sigmoid notch and extend posteriorly. Treatment of subcondylar fractures depends on severity and vector of dislocation, patient dentition, and systemic medical condition. It is important to point out the potential risk of necrosis of the proximal segment caused by loss of vascular supply during dissection in open reduction treatment. Intra- and extraoral approaches have been described for the treatment of subcondylar fractures; however, both approaches may be required to allow for adequate visualization, reduction, and fixation for the fractures.
Fractures located between the mandibular canine teeth are designated as symphyseal (mandibular midline) fractures and parasymphyseal (lateral to the mandibular midline) fractures. In most cases, these types of fractures are considered open because of involvement of the mandibular alveolus and teeth. The treatment challenge in these types of fractures is to avoid a lingual gap and splaying during reduction and fixation, which would inevitably lead to malocclusion. Widening of facial projection can occur when angle fractures are present. Other important factors to consider when treating these types of fractures are the vectors of compressive, tensile, and torsion forces present at the symphyseal region of mandible. These forces must be taken into account when planning reduction and fixation of fracture segments.
Fractures located between the mandibular canine and second molar are considered mandibular body fractures. If the fracture travels through the alveolus in the dentate patient, it is considered an open fracture. Special consideration should be given to treatment planning, surgical approach, and options for fixation of these types of fractures. Specifically, attention must be given to the location of the inferior alveolar and mental nerves. During the intraoral approach the mental nerve should be dissected and protected at all times. With the extraoral approach, attention must be given to the protection of the facial nerve during dissection and the location of the inferior alveolar nerve during fixation of fractures when using bicortical screws. Plate placement at the inferior border of the mandible via an extraoral approach can be done to avoid the path of the inferior alveolar nerve.
Indications for open reduction and internal fixation of mandibular fractures
Fractures that may require open reduction and internal fixation (ORIF) include open fractures, displaced fractures, severely comminuted fractures, multiple fractures (mandibular fractures in combination with condylar/subcondylar fractures), infected fractures, fractures in medically compromised patients, atrophic mandible fractures in edentulous patients, and patients for whom maxillomandibular fixation is contraindicated. The type of fracture and its location play a primary role in selecting the surgical approach and type of fixation required for proper reduction and stabilization of the fracture. Restoration of proper occlusion should be the primary goal; application of maxillomandibular fixation should be achieved as a first step. In edentulous patients, existing dental prostheses or fabricated splints should be used for proper alignment of the maxilla relative to the mandible. They can be used as an intraoperative guide for rigid fixation or be held in place during the entire bone-healing period.
Fractures located along the ascending ramus and posterior to the second molar are considered mandibular angle fractures. In many cases, these fractures traverse through partially or completely impacted third molars. These types of angle fractures pose several challenges for surgeons. If a third molar is partially impacted or comes into contact with the second molar, the fracture is considered to be an open fracture. Removal of an impacted third molar may displace fracture segments, which could potentially hamper adequate reduction and increase potential for inferior alveolar nerve injury. Angle fractures that require bicortical fixation are significantly displaced and occur in combination with other mandible fractures. Types of approaches and hardware used for fixation of these fractures are dictated by the location, displacement of fracture segments, comminution of fracture segments, position of third molar, and experience of the surgeon. A severely displaced left mandibular angle fracture is demonstrated in Figs. 1 and 2 .
