Percutaneous Approach to Mandibular Angle Fractures
Michael A. Carron
INTRODUCTION
Facial trauma is responsible for a substantial portion of injuries seen in the emergency room. The most common cause of injury is physical assault. However, falls, bicycle accidents, industrial accidents, motor vehicle accidents, and sporting injuries are also contributing elements. It is not unusual for victims of facial trauma to have a fracture of the mandible, and about 25% will occur at the mandibular angle. This injury is believed to occur due to the turning of the head upon attack, thereby exposing the angle of the mandible to the brute force. It is further susceptible to fracture because third molars occupy osseous space, thereby weakening the bone stock. Moreover, unique forces can act on the angle because it is a transition zone from the body to the ascending ramus of the mandible.
The region of the mandibular angle is very important as it plays a central role in the functional integrity of the jaw as well as facial aesthetics. Failure to properly reconstruct the mandibular angle may result in malunion or nonunion with resultant malocclusion, chronic pain, facial asymmetry, and impaired mastication. The treatment of these injuries requires expertise and becomes even more difficult and complex when patients have poor dentition, have poor oral hygiene, and are prone to miss appointments for follow-up care.
The repair of fractures of the mandibular angle can be performed through an external submandibular approach or percutaneously through an intraoral incision combined with a transbuccal trocar and screwdriver. The percutaneous approach reduces potential injury to the facial nerve and minimizes external incisions and scarring. However, when drilling holes and placing screws, the technique may be difficult in certain hard-to-reach areas of the mandibular angle.
HISTORY
Patients with a fracture of the mandible usually present to the emergency room with a complex history of trauma. The standard tenants of evaluating the trauma patient (airway, breathing, circulation, Glasgow Coma Scale, IV access) take priority over general patient history. Since the mandible is located in continuity to the floor of the mouth, edema or frank hematoma can displace the tongue posteriorly. Such a patient may present with difficulty breathing and harbor a significant potential for airway obstruction.
Once the trauma evaluation is complete and the patient is stabilized, attention is directed toward the events of the trauma, signs and symptoms related to these injuries, and the patient history. Questions regarding the current event, past surgical interventions, previous trauma, current medications, allergies, family history, and substance use are reviewed and recorded. The patient’s general health history is also obtained at this time and includes cardiac, pulmonary, hepatic, and renal systems. Depending upon the patient’s level of consciousness, the history may need to be obtained by family or accompanying others. Additional surgical specialists and social services are consulted as necessary.
PHYSICAL EXAMINATION
The physical examination is critical in assessing the fractured mandible. Examination allows the surgeon to determine the location and severity of the injuries. In addition to the standardized “top-down” head and neck examination, particular attention is drawn to the lower third of the face, teeth, lips, tongue, and gingiva. The surgeon should note the presence or absence of swelling over the fracture site, tenderness, and intraoral or external lacerations and possibly exposed bony fragments.
The teeth may be loose, chipped, or avulsed. All teeth and/or dentures need to be accounted for as they may be lodged in the patient’s airway. The patient should be questioned as to whether they detect any damage to the teeth or whether their occlusion is abnormal. Teeth create additional stability when repairing mandible fractures, and technical attention is needed in evaluation. Teeth that appear to be carious or devitalized from the injury should be considered for dental extraction to prevent complications. A dental or oral surgical colleague may need to evaluate the patient’s teeth if there is a question about their status.
Complaints of loss of sensation of the face, lips, or cheeks may be due to injury of the inferior alveolar nerve, which courses through the body of the mandible or the mental nerve as it exits the mandible between the first and second premolars. Gentle rocking of the mandible will allow the surgeon to evaluate for and document the location of any mobile segments of the mandible. Occasionally, the fracture is “open” with a laceration of the gingiva at the site of injury with bleeding from the marrow space of the bone. Angle fractures often will occur with opposite condylar or parasymphyseal fractures. The examining physician should keep in mind that multiple fractures are often a rule and not the exception.
INDICATIONS
Prompt care of this injury is important as unrepaired mandibular fractures are painful and may also result in malocclusion, open bite deformity, as well as impaired speech, chewing, or swallowing. The goal of internal fixation is to reestablish bony union, prevent nonunion or malunion, and initiate early mobilization of the condyle to avoid ankylosis. For a simple favorable linear fracture of the mandibular angle, the percutaneous approach applying a Champy miniplate should be considered. For unfavorable fractures or fractures complicated by absent teeth, compression, noncompression, or a locking plate would be indicated. The particular plate and screws selected need to ensure neutralization of the functional forces on the angle of the mandible to allow stable bone healing (Fig. 49.1). The percutaneous approach provides minimal morbidity and minimal
soft tissue dissection and avoids potential damage to neurovascular and glandular structures of the cheek. Additionally, the intraoral incision used with the percutaneous approach may be advantageous when the surgeon needs to remove a molar tooth from the fracture site.
soft tissue dissection and avoids potential damage to neurovascular and glandular structures of the cheek. Additionally, the intraoral incision used with the percutaneous approach may be advantageous when the surgeon needs to remove a molar tooth from the fracture site.
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