Fracture of the Mandible in Dogs
Dr. David Diamond
Motor vehicle trauma is a frequent cause of mandibular fractures in dogs, as well as falling from a height (such as out a window) and landing on the face. Dogs of both sexes and of any age are susceptible to this type of trauma if not kept properly restrained.
Dogs can also develop non-traumatic fractures of the mandible when certain disease conditions exist. These fractures, also known as "pathologic fractures," can occur if the dog has severe dental disease leading to destruction of the bone supporting the teeth, is malnourished, has a systemic illness such as kidney disease, has an endocrine disorder such as hyperparathyroidism, has a bone infection (osteomyelitis) or has cancer of the bone.
Symptoms caused by fracture of the mandible may be relatively subtle, with reluctance to play or chew on toys or food, or more obvious, with inability to close the mouth, bloody saliva dripping from the mouth, or inability to eat at all.
The mandible is one of the hardest bones in the body and a great deal of force is necessary to break the bone. Frequently the two halves of the mandible split at the midline (mandibular symphysis fracture). Also instead of a true fracture, the temporo-mandibular joints may dislocate (luxate) making the jaw non-functional.
When the bone does break, the fracture can occur on one or both sides, can be "simple," if the bone breaks into two pieces, or "comminuted," if there are multiple pieces, and can occur anywhere along the length of the bone. Because there is relatively little soft tissue covering the mandibles in the mouth, these fractures are usually "open" (bone exposed). Open fractures have a greater chance of getting infected and may have more complications than closed fractures.
Each case of mandibular fracture needs to be evaluated in its entirety (age of animal, severity of the fracture, experience of the surgeon, and financial concerns of the owner) to determine the most appropriate and best form of treatment.
Inappropriate case management, inadequate surgical stabilization or poor aftercare can lead to complications such as non-unions (fractures that will not heal), malunions (fractures that heal in an abnormal direction or orientation resulting in malocclusion of the teeth and difficulty chewing), or osteomyelitis (bone infection).