What is the mandible?
The mandible is the bone of the lower jaw of the cat. It is split into the right and left mandible. The teeth on the lower jaw all insert into the mandible. The two sides of the lower jaw are joined at the front at the mandibular symphysis.
How could mandibular fracture happen?
The most common cause of mandibular fracture is due to trauma such as in a road traffic collision.
What are the signs?
In general the signs are: swelling in the area, a loss of symmetry of the lower jaw and potentially the loss of teeth in the affected region. The lower jaw may also droop on the affected side. A mandibular fracture will also be painful.
How is it diagnosed?
Most of the time a physical examination performed by the veterinary surgeon will be sufficient to diagnose a mandibular fracture, but further imaging via x-rays or a CT scanner will be necessary to confirm the extent of the fracture. In order to properly examine the extent of the fracture your cat may have to be anaesthetised in order to conduct a full assessment.
Treatment of mandibular fractures depends on the fracture that has occurred and the location of the fracture in the mandible.
Mandibular symphysis fractures
This is the most common type of mandibular fracture in cats. Fractures of the mandibular symphysis can be treated with the use of a cerclage wire which is placed around the two side of the lower jaw to align the bones.
Fractures of the body of the mandible
The main part of the mandible is the body. These fractures can be aligned by using a tape muzzle which is non-surgical treatment. However, this is difficult to apply to a cat and oftentimes surgery is required. These treatments include:
- External skeletal fixation
- Pins are placed into the bone, through the skin and are held in place by a a connecting bar or block of acrylic on the outside
- Interdental wiring and acrylic splinting
- A wire is placed in between the teeth and a splint made from acrylic is placed along the fracture line. This is done to hold the areas of broken bone in place.
- Internal Fixation
- Bone plates and screws can be used to hold the bone ends together. Some cats are too small and this treatment is not appropriate. However, the use of mini-plates has been reported in cats.
Fractures of the vertical portion of the mandible
- External Skeletal fixation can be used if the fracture is displaced enough
- Use of a BEARD (Bi-gnathic Encircling and Retaining Device) can be used to treat these
- This is a device that is relatively easy to apply and helps to fix the cats jaw in place to allow the fracture to heal.
Postoperative care for animals with jaw fractures will include a soft food/liquid diet for a significant period of time whilst the fracture is healing. In some cases, a food tube is placed into the oesophagus to assist feeding. Daily rinsing of the mouth may also be needed to ensure the mouth is kept clean.