Fracture of the Mandible in Dogs
Dr. David Diamond
Examination of the oral cavity. This may be suggestive of a mandibular fracture. Commonly found abnormal findings include broken teeth, disruption and hemorrhage from the gum line, jaw instability, crepitation (abnormal "crunchy" feeling with motion), swelling, and pain along the body of the mandible, or malocclusion (misalignment of the upper and lower teeth).
Thorough physical examination is very important to make sure your pet is not showing signs of hypovolemic shock secondary to the trauma or blood loss. It is also important to make certain that there are no other injuries present. Additional tests include:
Thoracic radiographs (chest X-rays). Chest trauma, in the form of pulmonary contusions (bruising) or pneumothorax (collapsed lung lobes secondary to free air within the chest cavity), must be ruled-out with chest radiographs prior to anesthesia to repair the jaw.
Complete orthopedic examination. A complete orthopedic examination must be performed to look for other possible injuries in other bones or joints caused by the trauma. Examination involves palpation of all of the bones and joints of each leg for signs of pain or abnormal motion within a bone or joint as well as an assessment of the neurological status of each leg. The thorough orthopedic examination is especially important for an animal that is unable or unwilling to get up and move.
A complete neurological examination. This is extremely important for an animal that has suffered trauma to the head. Damage to the brain and other important nerves in the head may result in temporary or permanent deficits that may need to be treated quickly and must be considered when planning a course of treatment for other injuries, such as a mandibular fracture.
Radiographs of the jaw. Several radiographic views of the animal's jaw are used to confirm the diagnosis of mandibular fracture and may show luxation of the temporo-mandibular joints if present. Because most mandibular fractures are painful and most animals will not allow the jaw to be X-rayed while they are awake, anesthesia is usually necessary. Based on the location and severity of the fracture, a more informed discussion with the owner can occur regarding potential treatments, prognosis and costs.
No laboratory tests are required to make the diagnosis.
Emergency care for concurrent problems is the first part of treatment. Shock is a frequent result of major trauma and must be treated quickly. Treatment for shock involves intravenous fluid administration to maintain blood pressure and adequate oxygen delivery to the body. Injury to the lungs and chest cavity are also commonly seen after major trauma and may require supplemental oxygenation or removal of free air (pneumothorax) from around the lungs. After emergency treatment has begun, additional treatments include:
Soft-tissue injuries must be addressed in order to minimize the chance for the development of wound infections. Lacerations and other open wounds or open fractures must be cleaned of debris and covered or closed to minimize infections.
In the interim between treating the emergency patient and surgical repair of the mandibular fracture, all of the orthopedic injuries that have been found should be addressed with splints and/or pain medications to keep the animal comfortable until they can be properly addressed.
Depending on the specific fracture type, location, and age of the animal, mandibular fractures may be repaired in many different ways. Some fractures, especially those in a younger animal with a long nose that have not caused misalignment of the bone fragments or teeth may be managed with a "tape muzzle." Symphyseal fractures are usually repaired with a single wire placed around the two halves of the jaw.
Methods for surgical stabilization of other mandibular fractures include wires placed around the teeth, wires placed in the bone, bone plates and screws, and external fixators (pins holding the bone fragments stable through holes in the skin, like a scaffolding). Each of these methods may be used separately or in combinations to provide stability to the bone fragments while they heal. In some cases, the upper and lower jaws may be wired together or the upper and lower canine teeth may be temporarily cemented together to hold the fragments in position while the bones heal. These dogs may require the use of a feeding tube placed directly into the esophagus or stomach to allow nutrition and hydration without the need for chewing and swallowing.
Mandibular fractures, as well as any other traumatic injuries that the animal might have, are painful and the animal will be given analgesics before and after surgery.
Open fractures of the mandible are susceptible to infection from bacteria and other debris in the animal's mouth and antibiotic therapy may be given while the animal is in the hospital and continued at home to prevent systemic infection.