In medical terms, a jaw fracture is called a “mandibular fracture” as it is a fracture of the mandible or jaw bone. It is a common fracture in both car accidents and in altercations as the mandible is prominent and gets hit before other bones.
What is a Jaw Fracture?
A jaw fracture or mandibular fracture involves a fracture of the bone that causes the mouth to open and close. Fractures of the mandible are often multiple and involve the mucosa of the mouth so that infections are likely. It also results in the teeth being out of place until the fracture is fixed.
The mandible is a thick bone that takes a great deal of pressure and force to break. Whenever someone sustains a mandibular fracture, the doctor must also rule out other major injuries, such as a cerebral spine injury and a head injury with internal bleeding. The bone is an irregularly shaped bone that forms a U-shape in the middle with a portion that goes up on either side in order to form the condyle, which is the part of the bone that fits in the socket in front of the ear and acts as a hinge to open and close the mouth. When the bone is fractured in any part of the bone, the bite is abnormal.
Causes of a Jaw Fracture
There are no medical reasons for getting a jaw fracture. All reasons behind a fracture of the mandible are related to physical trauma unless a person has some kind of bony tumor causing a weak bone. Several causes of a fracture of the jaw include the following:
- An accidental fall in children while playing
- A fracture of the mandible after an adult faints and falls forward
- A motorcycle accident where the rider flies over the handlebars
- A motor vehicle accident in which the person hits the dashboard with their chin
- An injury sustained in a sporting event
- A fall from a bicycle
- A violent act in which the person is punched in the jaw
The jaw tends to jut out over many of the other bones of the face, making it the obvious bone to be struck first in an injury.
Risk Factors for a Jaw Fracture
Those at greatest risk for a fracture of the jaw are those people who engage in risky behaviors like riding a bicycle or motorcycle without a helmet, work or play in high places, engage in rough sports and engage in fights with other people. Research has shown that the prevalence of jaw fractures is much higher in males and Caucasians and is highest in the third decade of life. The most common site of fracture is the mandibular condyle, followed by the body of the mandible.
Symptoms of a Jaw Fracture
Most people who experience a jaw fracture have considerable pain, bruising, and swelling at the site of the fracture or fractures. Because of the shape of the bone, it is often fractured in more than one place. The jaw may not open at all or it may slide from side to side when an attempt is made to open it.
Many fractures of the jaw go into the alveolar bony area that houses the teeth. Whenever there is a jaw fracture and the mouth is bleeding, the bleeding site usually represents the site of an open fracture where the mouth bacteria communicate with the fractured bone. This is where infection can get into the fracture site and cause a bony infection.
Often, there is a crunching sound on attempting to open and close the jaw, especially if the condyle (the joint that connects with the side of the face) is fractured. The crunching is quite loud to the person with the fracture as it is occurring just in front of the ear.
Teeth can be dislodged in a jaw fracture, especially at the site of the fracture and if the fracture is out of place. The teeth can often not be placed back in the mouth until the fracture is put into its proper place and even then the tooth may have to be wired into the jaw until it can heal.
Diagnosis of Jaw Fractures
The doctor can be suspicious of a fracture of the mandible when the person has an uneven bite or is unable to open the mouth at the temporomandibular joint. There will be pain and swelling on palpation of one or more areas of the jaw itself and there will likely be bleeding from areas in the mouth.
A plain film x-ray used to be the only way to diagnose a fracture of the jaw and it is still used in some cases to screen the patient for fractures. Both anterior and lateral plain films can show defects in the cortex of the bone consistent with fracture.
A CT scan of the jaw bone is a good way to identify all the possible bony fractures in the jaw bone. A CT scan will show cross-sectional views of all the bones of the skull to the cervical spine and gives the added advantage of showing fractures in any of these areas with great detail. The doctor can use the information gleaned from the CT scan to identify areas where the mandible needs to be repaired.
There is a newer technology that isn’t available at all hospitals is called a Panorex. It takes a three dimensional picture from one side of the mandible to the other and is often used by dentists to take a picture of the entire mouth at once. When used for trauma, it best picks up fractures of the body of the mandible and shows any fractures of teeth.
When the diagnosis has been made by the different technologies available, the doctor can enlist the services of an oral surgeon or a maxillofacial surgeon to repair the fractures.
Treatment of a Jaw Fracture
If there is any chance whatsoever that one or more of the fractures of the mandible are open, such as a finding of lacerations and bleeding inside the mouth, preoperative antibiotics are given to protect the fracture from becoming infected. Antibiotics after the repair are usually unnecessary unless the wound was particularly dirty.
The surgery to repair the jaw fracture can be open or closed. In both cases, however, the patient’s jaw is wired shut. Metal bars for both the maxillary teeth and the mandibular teeth are attached to the teeth and wires or rubber bands are used to put the bite into its proper position. Any teeth that are fractured are removed as are any teeth with a fair amount of periodontal damage (because the tooth will likely not make it anyway). These bars used to put the bite in place are called Erich arch bars.
In a closed reduction, the teeth are pulled tightly into alignment, which pulls the bony segments into proper alignment. The person must have their jaw wired shut for a period of time so that the bones heal in the proper place. This particular technique cannot be done if the patient has no teeth or has teeth that are in poor condition. In addition, if the fracture is comminuted and unstable, this wiring technique cannot be done.
Sometimes a technique using a bridle wire is done to stabilize the fracture for a period of time and to reduce pain. Two opposing teeth are looped together and tightened by rotating the wire in a clockwise fashion. Such a procedure can be done under local anesthesia. The doctor pushes the bony segments back into place manually. It also can’t be done in cases of an unstable fracture.
If the individual has only some teeth, an existing partial denture can be used to put the maxillary part of the fracture into position. If there is no partial denture, an acrylic block is fashioned with an arch bar to put the teeth into proper position. If the patient has no teeth at all, the mouth bite can be secured using wires or screws.
Dentures can be made that are screwed in to hold the bony fragments in place. Pins can also be used in patients who have no teeth.
Open reduction of jaw fractures is rarely used because there are so many good techniques for wiring or screwing the jaw in a closed reduction. Sometimes open reduction is a good idea when attempting to align the fracture fragments before going on to do a rigid fixation. A straight wire is used to fix the segments of bone in some cases and a figure of eight wire is used in other cases.
If surgery and internal fixation is required of a jaw fracture, there can be several approaches. In one, an incision is made inside the mouth. It is a faster way of repairing the fracture and it leaves no external scar. There is also less risk to the facial nerve using an intraoral approach and there is no increase in complication rate when compared to doing an external approach. There are several incision sites available within the mouth so just about any mandibular fracture can be repaired that way.
Another approach makes the incision externally in the inferior aspect of the mandible. The approach is called the Risdon Approach because of a Dr. Risdon who first described it in 1934. The bony mandible is exposed and a rigid internal plate is affixed to both halves of the fracture. This will stay in place and will be a permanent part of the person’s anatomy for the rest of their lives.
There is also a retromandibular approach, first used in 1958 by a Dr. Hinds. The incision is made just under the earlobe. It carries a risk of damage to the facial nerve if not done in capable hands. The preauricular approach puts the incision just in front of the ear. This is probably the best approach for fractures involving the temporomandibular joint. This approach, too, carries risk to the facial nerve as well as the parotid gland.
When repairing jaw fractures, injuries to the teeth and inside of the mouth must be treated at the same time. Many doctors wire the teeth to the right occlusion first and then fix the aspect of the bone that is unstable or not in the right position using internal surgical approaches. After the jaw is properly wired shut and the bone is fixed with plates and screws, the teeth can be loosened somewhat by using rubber bands instead of wires to allow for some opening and closing of the jaw.
There is some controversy about what to do with teeth that are in line with the mandibular fracture. A recent study showed that it didn’t matter whether the teeth in line with the fracture were removed or were kept in, in the hope that they survive. If the tooth is highly mobile, has root exposure, a tooth fracture or severe dental caries, it should naturally be removed at the time of the surgical repair. In total, the complication rate for teeth in the line of fractures is between 13 and 16 percent.
Antibiotics need to be used in order to reduce the risk of infection in the fracture area. Impacted molars, like wisdom teeth, should be left in place to make for the best healing. Teeth that get in the way of the fracture being reduced should obviously be removed. Teeth that have exposed roots tend to develop periodontal infections so these should be removed at the time of the repair.
Complications of a Jaw Fracture
There are many types of complications that can happen with jaw fractures. There can be a delay in the union of the fracture or a nonunion, which happens three percent of the time. Nonunion shows up as ongoing pain and abnormal movement of the jaw. It is often secondary to an infection in the system. Decreased blood supply can also lead to a nonunion.
Infection is a common complication of mandibular fractures and can develop in more than half of all fractures, especially if antibiotics are not used. If the person is alcoholic or immunosuppressed, infections are even more likely. If the fracture is comminuted, if teeth are broken or if the reduction and fixation did not go well, infections can occur. Doctors must start antibiotics and debride infected areas in order to heal the infection.
Malunion is always a possibility. This can happen whenever there has been improper alignment of the bony fragments. Generally they are fixed because they are associated with malocclusion of the teeth and increased pain.
Ankylosis is an injury that occurs following jaw fractures in children. It is believed to occur because of bleeding into the joint that turns into fibrous tissue and the jaw joint becomes fixed. It can result in underdevelopment of the side of the injury as the child grows.
Nerves can be injured in a jaw bone fracture. The most commonly injured nerves are the inferior alveolar nerve and the branches of the nerve. It can lead to numbness or tingling in the chin and lower lip. Damage to the facial nerve is fortunately uncommon except in cases of fracture of the condyle, ramus, and the angle of the mandible.
Fortunately, if there are motor or sensory deficits caused by a jaw fracture, the nerves heal over time and the symptoms are gone.
If you or a loved one has suffered a jaw fracture as a result of someone else's negligence and would like to discuss your legal options with an experienced Sacramento Personal Injury Attorney, contact us online or call us at 916.921.6400 to set up a FREE consultation.