Author: Dr Andrew H. Murr University of California San Francisco 2008-08-14
Jaw Fractures: Fractures of the Mandible Fractures of the jaw or mandible are a fairly common occurrence in our society. Although jaw fractures very often occur because of interpersonal trauma or fights, motor vehicle accidents and sporting injuries or falls also can cause jaw fractures. Typically, jaw fractures require treatment, and surgery is often recommended. This Knol will discuss jaw fractures and describe different methods of promoting healing of the fracture.
Jaw Fractures: Fractures of the Mandible Fractures of the jaw or mandible are a fairly common occurrence in our society. Although jaw fractures very often occur because of interpersonal trauma or fights, motor vehicle accidents and sporting injuries or falls also can cause jaw fractures. Typically, jaw fractures require treatment, and surgery is often recommended. This Knol will discuss jaw fractures and describe different methods of promoting healing of the fracture.
INTRODUCTION
Fractures of the jaw or mandible are
a fairly common occurrence in our society. Although jaw fractures very
often occur because of interpersonal trauma or fights, motor vehicle
accidents and sporting injuries or falls also can cause jaw fractures.
Typically, jaw fractures require treatment, and surgery is often
recommended. This Knol will discuss jaw fractures and describe
different methods of promoting healing of the fracture.
BACKGROUND
The
jaw and chin occupy a prominent position in the facial skeleton. The
lower jaw is commonly known as the mandible. The primary function of the
mandible is to mesh with the upper jaw, or maxilla, and to chew or
grind food. The mandible also functions to permit normal speech
articulation. Finally, the mandible is an anchor for muscle attachments
to the tongue and other muscles involved with eating. These muscles
are referred to as the muscles of mastication. By providing for muscle
attachments, the mandible allows the airway to remain open and therefore
has a partial function in providing breathing. The mandible is where
the teeth reside. In fact, the upper surface of the mandible is
comprised of the alveolar bone, which supports the teeth and anchors
the teeth to the jaw. If teeth are not present, this alveolar bone
resorbs and the bone of the mandible becomes less bulky and in general
more weak or atrophic. The sensation to the jaw and lip is provided by a
branch of the trigeminal nerve which is the 5th cranial nerve. The
lower, or third division of this nerve, has a branch that runs right
through the center of the mandible and is called the inferior alveolar
nerve. This nerve exits the jaw at the mental foramen and then
innervates the lower lip. The fact that this inferior alveolar nerve
runs right through the center of the jaw is critical when planning
different surgical treatments to fix mandible fractures. An excellent
description of the anatomy of the human mandible may be found at:
http://education.yahoo.com/reference/gray/subjects/subject/44
For a single bone, the mandible is surprisingly well studied. In fact, the mandible is commonly broken down into different regions which are roughly based upon where fractures occur. The mandible regions include the following areas: the condyle, the ramus, the angle, the body, the parasymphysis and the symphysis.
The condyle is the most posterior portion of the mandible, that is, furthest from the chin, and is the jaw joint. The condyle articulates with the skull base in the glenoid fossa of the temporal bone, which is the bone that contains the ear. The jaw joint is a complex structure that can be responsible for temporal mandibular joint syndrome, an uncomfortable condition that occurs when the articulation of the jaw is under strain for one reason or another. It is sometimes said that condyle fractures are the most commonly encountered jaw fractures. This may or may not be true. The American Dental Society is a good source of information about the function of the jaw joint: http://www.ada.org/public/topics/tmd_tmj.asp
The ramus is the portion of the jaw that allows the vertical rise to the condyle. This is one of the least frequently fractured portions of the jaw, probably because there are a lot of muscle attachments for the muscles of mastication in this portion of the jaw. The muscles of mastication function to allow chewing and speaking.
The angle of the mandible is just behind the posterior teeth. This is also a commonly fractured area of the jaw and it has a relatively low surface area which makes repair in this area somewhat tricky.
The body of the jaw contains the teeth and also has the inferior alveolar nerve running right through it. This is thick bone, but because it contains the teeth, fracture repairs through this area must be lined up perfectly to ensure a good result when healed.
The parasymphysis is the forward area of the jaw, just in front of the body. The mental foramen is in this region, which allows passage of the sensory nerve. This commonly fractured area often directly involves the mental foramen, which is a weak point of the bone. Teeth are also present in this segment.
The symphysis is the front part of the jaw, or chin, and contains the anterior incisor teeth. It is unusual to have a fracture directly in the symphysis, but not impossible.
For a single bone, the mandible is surprisingly well studied. In fact, the mandible is commonly broken down into different regions which are roughly based upon where fractures occur. The mandible regions include the following areas: the condyle, the ramus, the angle, the body, the parasymphysis and the symphysis.
The condyle is the most posterior portion of the mandible, that is, furthest from the chin, and is the jaw joint. The condyle articulates with the skull base in the glenoid fossa of the temporal bone, which is the bone that contains the ear. The jaw joint is a complex structure that can be responsible for temporal mandibular joint syndrome, an uncomfortable condition that occurs when the articulation of the jaw is under strain for one reason or another. It is sometimes said that condyle fractures are the most commonly encountered jaw fractures. This may or may not be true. The American Dental Society is a good source of information about the function of the jaw joint: http://www.ada.org/public/topics/tmd_tmj.asp
The ramus is the portion of the jaw that allows the vertical rise to the condyle. This is one of the least frequently fractured portions of the jaw, probably because there are a lot of muscle attachments for the muscles of mastication in this portion of the jaw. The muscles of mastication function to allow chewing and speaking.
The angle of the mandible is just behind the posterior teeth. This is also a commonly fractured area of the jaw and it has a relatively low surface area which makes repair in this area somewhat tricky.
The body of the jaw contains the teeth and also has the inferior alveolar nerve running right through it. This is thick bone, but because it contains the teeth, fracture repairs through this area must be lined up perfectly to ensure a good result when healed.
The parasymphysis is the forward area of the jaw, just in front of the body. The mental foramen is in this region, which allows passage of the sensory nerve. This commonly fractured area often directly involves the mental foramen, which is a weak point of the bone. Teeth are also present in this segment.
The symphysis is the front part of the jaw, or chin, and contains the anterior incisor teeth. It is unusual to have a fracture directly in the symphysis, but not impossible.
How Fractures of the Jaw Occur
The
most common cause of jaw fractures is a fist fight. A fist will
usually produce two jaw fractures at once: usually a parasymphysis
fracture accompanied by an angle or condyle fracture on the opposite
side. This is a very common combination seen in emergency rooms
throughout the United States. Of course, the direction of the blow and
the presence or absence of teeth, and the strength of the bone are all
factors that influence the injury. A direct fall forward, which impacts
the front of the chin, is another somewhat frequent pattern. This also
can create two fractures, either through both condyles or through a
condyle and an angle. This type of fall is seen in children who are
running and trip, or sometimes in people who fall off a bicycle over the
handlebars. Steering wheels on cars could also produce this type of
injury, but now that airbags are in many cars, this cause seems to have
decreased. Sports injury from balls or kicks, or from sliding or
falling down during play, are also a common source of injury. Injuries
from a thrown elbow in sports like basketball can result in jaw
fractures as well. Use of mouth guard and helmets in contact sports may
help to reduce the incidence of dental injury and jaw fractures.
The main symptom of a mandible fracture is pain. Direct pain in the area of a recent blow would certainly raise the question of a fracture to the jaw. Another major symptom is malocclusion. This is a fancy word for when teeth don’t fit together correctly. The teeth usually fit together quite perfectly (or at least in a familiar way) when the jaw is clenched. A fracture through the jaw will disrupt this fit and usually the victim will be highly aware that something is wrong. Normally, the way teeth fit, or occlusion, is classified into three types. Type I occlusion is normal and is described to be present when the maxillary first molar cusp on the outside toward the cheek articulates with a groove in the mandibular first molar. If the jaw protrudes forward of this point, the occlusion is said to be Class III and if the jaw retrudes the occlusion is said to be Class II. Sometimes, when a fracture occurs, the teeth will contact prematurely and this is referred to as an anterior open bite as the jaw will not be able to fully close. Other times, the teeth do not fit properly cross wise and this is referred to as a cross bite. Numbness of the lip is another common symptom of a jaw fracture if the fracture goes through the nerve canal and stretches or severs the inferior alveolar sensory nerve. Of course, bleeding from the mouth can also accompany jaw fractures. A cracked tooth or missing teeth can be associated with jaw fractures. Although these symptoms all seem quite severe, it is common for patients who have sustained jaw fractures to delay seeking attention. Often, if a fight has lead to a fracture, substance abuse such with alcohol or illicit drugs, has played a part and patients will be too obtunded to recognize the seriousness of the injury right away. They may wait a few days before noticing something is wrong or seeking medical attention.
Symptoms of Jaw Fracture:
The main symptom of a mandible fracture is pain. Direct pain in the area of a recent blow would certainly raise the question of a fracture to the jaw. Another major symptom is malocclusion. This is a fancy word for when teeth don’t fit together correctly. The teeth usually fit together quite perfectly (or at least in a familiar way) when the jaw is clenched. A fracture through the jaw will disrupt this fit and usually the victim will be highly aware that something is wrong. Normally, the way teeth fit, or occlusion, is classified into three types. Type I occlusion is normal and is described to be present when the maxillary first molar cusp on the outside toward the cheek articulates with a groove in the mandibular first molar. If the jaw protrudes forward of this point, the occlusion is said to be Class III and if the jaw retrudes the occlusion is said to be Class II. Sometimes, when a fracture occurs, the teeth will contact prematurely and this is referred to as an anterior open bite as the jaw will not be able to fully close. Other times, the teeth do not fit properly cross wise and this is referred to as a cross bite. Numbness of the lip is another common symptom of a jaw fracture if the fracture goes through the nerve canal and stretches or severs the inferior alveolar sensory nerve. Of course, bleeding from the mouth can also accompany jaw fractures. A cracked tooth or missing teeth can be associated with jaw fractures. Although these symptoms all seem quite severe, it is common for patients who have sustained jaw fractures to delay seeking attention. Often, if a fight has lead to a fracture, substance abuse such with alcohol or illicit drugs, has played a part and patients will be too obtunded to recognize the seriousness of the injury right away. They may wait a few days before noticing something is wrong or seeking medical attention.
Initial Management of Jaw Fractures
Once
a jaw fracture is suspected, the injured person should seek the
services of an Emergency Department. Usually, the discomfort of a
mandible fracture is so great that immediate attention is preferred.
Also, other injuries may be present and it takes the full services of an
emergency department to look into the injury to make sure that the
injury is isolated. It is not unreasonable to dial 911 to travel by
ambulance, especially if the injured party has lost consciousness.
Otherwise, if the injured person is conscious and can walk, a ride to
the hospital without delay is the best advice. The American Academy of
Otolaryngology-Head and Neck Surgery has a Web site that gives some
basic information about initial management in the field for injured
patients: http://www.entnet.org/healthinfo/topics/sport_injuries.cfm
Emergency Room: in the emergency department, a stable ability to breathe will be the most immediate concern of the caregivers. Depending on the injury, many different types of evaluation will be ordered. Emergency departments will often assess for neck injury by obtaining x-rays designed to document the normal continuity of the cervical spine. Bleeding will be controlled. A complete physical examination will be accomplished and a special directed exam toward sites of suspected injury will be done. If injuries to other parts of the body are suspected, they will be assessed. Finally, x-rays of the jaw will be obtained and a computerized x-ray or CT scan of the facial bones may be ordered. CT scans are quite good at showing mandible injuries. Once the injury is documented, a number of different consultations may be requested. In general, plastic surgeons, otolaryngologist- head and neck surgeons, or oral and maxillofacial surgeons are the types of doctors and dentists that take care of jaw fractures. The facial trauma surgeon may be able to review the films that have been obtained remotely via a computer. If this is the case, they will be able to help to make a decision as to whether hospital admission is necessary to stabilize the injured person. Eventually, options for repair of the fracture will need to be discussed with the injured patient.
Emergency Room: in the emergency department, a stable ability to breathe will be the most immediate concern of the caregivers. Depending on the injury, many different types of evaluation will be ordered. Emergency departments will often assess for neck injury by obtaining x-rays designed to document the normal continuity of the cervical spine. Bleeding will be controlled. A complete physical examination will be accomplished and a special directed exam toward sites of suspected injury will be done. If injuries to other parts of the body are suspected, they will be assessed. Finally, x-rays of the jaw will be obtained and a computerized x-ray or CT scan of the facial bones may be ordered. CT scans are quite good at showing mandible injuries. Once the injury is documented, a number of different consultations may be requested. In general, plastic surgeons, otolaryngologist- head and neck surgeons, or oral and maxillofacial surgeons are the types of doctors and dentists that take care of jaw fractures. The facial trauma surgeon may be able to review the films that have been obtained remotely via a computer. If this is the case, they will be able to help to make a decision as to whether hospital admission is necessary to stabilize the injured person. Eventually, options for repair of the fracture will need to be discussed with the injured patient.
Hospital Admission
It
is not mandatory to admit patients with jaw fractures to the hospital,
but often they are admitted because of the discomfort of the fractures.
It hurts to chew and therefore eating diminishes. In the hospital
setting, fluids can be replaced via intravenous lines and pain control
can be maximized. Diet orders often emphasize soft and easy to chew
foods. Further imaging studies can be ordered if deemed necessary.
Plans for treating the fracture can be made.
Treatment Options
If
you break an arm, you can put your arm in a cast. If you break your
jaw this is not as obvious an option. The problem with fractures of the
jaw is that in order to stabilize the fracture properly, it would have
to be casted for about 4 to 6 weeks. This would make it hard to speak
and hard to chew. However, it can be done. In the United States
Intermaxillary Fixation (IMF) is accomplished using braces called Erich
Arch Bars, which are wired onto the teeth. There are several other
methods of wiring a jaw together such as the use of wire loops known as
Ivy loops or the use of special lugs that are glued onto teeth. These
arch bars have tabs or lugs that can be used to wire the jaws together.
By fitting the teeth together, effective splinting can occur which will
position the jaw fragments together so that they are immobilized. Once
the fragments are stable and immobilized, they can then heal, which
takes about 4 weeks. The problem is that it is very difficult to eat
and speak when the jaw is wired together, so patients generally don’t
like this treatment. A number of different types of IMF exist, including
using certain types of custom jaw screws that are designed to hold
wires. Sometimes, dentist can put on braces with composite material
that will work to keep the jaws wired shut. One of the key problems
with wiring the jaws shut is that if this is done for about a month, it
becomes harder for the jaw joint to work again. The joint can become
stiff and this can lead to difficulty with jaw function after the IMF
hardware is removed. This is called TMJ (temporomandibular joint)
ankylosis. If TMJ ankylosis occurs, a lot of physical therapy is
necessary to overcome the problem – a process that can take many months.
There is a special device called a TheraBite that can be used to
facilitate rehabilitation after jaw fractures:
http://www.atosmedical.com/Products/Mouth_Jaw.aspx
Other alternatives exist to allow earlier function of the jaw. The AO/ASIF is an international organization that is devoted to using surgical technology to provide stable fixation of mandible fractures designed to allow earlier function than that which can be achieved with IMF techniques. The AO/ASIF is an international organization and maintains a website: http://www.aofoundation.org
Other alternatives exist to allow earlier function of the jaw. The AO/ASIF is an international organization that is devoted to using surgical technology to provide stable fixation of mandible fractures designed to allow earlier function than that which can be achieved with IMF techniques. The AO/ASIF is an international organization and maintains a website: http://www.aofoundation.org
The principles of the AO/ASIF allow for the use of titanium bars that
are fixed to the jaw bone with screws. The idea is that implanted
titanium bars or plates can reconstruct the strength of the jaw and
allow the jaw to function much earlier, in many cases right after they
are surgically placed. Why titanium? It turns out that titanium is one
of the few substances that will not be rejected from the body. Back in
the late 1970s and early 1980s a Scandinavian scientist named
Per-Ingvar Brånemark discovered that titanium was highly compatible with
bone (http://www.branemark.com/ ) By designing plates and screws out of
titanium, jaw fractures could be managed so that the jaw could be
placed back into function right away. The bio-compatibility of titanium
is even more remarkable when you consider that the oral cavity, or
mouth, is an environment that is completely contaminated by many
different bacteria and therefore prone to infection. Yet, the titanium
plates, once placed, usually will stay in place and not become infected
or loose.
Nevertheless, in order to use these titanium plates to re-approximate the fractured ends of the bone, surgery must be performed. Incisions are made either inside the mouth or outside the jaw on the skin. Sensory nerves are preserved if possible, as are branches of the facial nerve which allow the lip to move. Then, the surgical principle is to clean out the fracture line, and approximate the fractured ends of the bone as perfectly as possible. Then, an optimal combination of plates and screws must be selected from a number of different engineered choices. The plates must be meticulously placed onto the bone and optimally positioned so as not to damage the teeth or the sensory nerve to the jaw. Although this is actually quite a complicated process, surgeons understand certain engineering principles so that the force of using the jaw can be overcome by placing the titanium plates and screws in the best possible configuration. If this is done as planned, after the wound is closed and the patient awakened from anesthesia, the jaw will usually be able to function either immediately or within a week or so. This technique is referred to as ORIF or Open Reduction and Internal Fixation.
Nevertheless, in order to use these titanium plates to re-approximate the fractured ends of the bone, surgery must be performed. Incisions are made either inside the mouth or outside the jaw on the skin. Sensory nerves are preserved if possible, as are branches of the facial nerve which allow the lip to move. Then, the surgical principle is to clean out the fracture line, and approximate the fractured ends of the bone as perfectly as possible. Then, an optimal combination of plates and screws must be selected from a number of different engineered choices. The plates must be meticulously placed onto the bone and optimally positioned so as not to damage the teeth or the sensory nerve to the jaw. Although this is actually quite a complicated process, surgeons understand certain engineering principles so that the force of using the jaw can be overcome by placing the titanium plates and screws in the best possible configuration. If this is done as planned, after the wound is closed and the patient awakened from anesthesia, the jaw will usually be able to function either immediately or within a week or so. This technique is referred to as ORIF or Open Reduction and Internal Fixation.
Very often antibiotics, anti-inflammatory medication, and pain medicine are needed to recover from surgery. Also, meticulous care of the wounds and close follow-up with the doctor help to produce the best results.
RECOVERY
During
the recovery period, which usually lasts about 4 to 6 weeks, patients
are encouraged to stay on a soft food oriented diet. High caloric
liquids such as milk shakes and fruit juices may be necessary to
maintain weight. Ensure is a liquid dietary supplement which may be
recommended. Blenderized foods are often encouraged. Difficult to chew
foods such as hard candy or steaks should be avoided at first.
Chlorhexidene antibiotic mouthwash or other mouthwash is often
prescribed as are antibiotics and pain medication. Use of a water pik
irrigation device may be encouraged to maintain dental health. Wax
designed for people with braces can be used to cover any sharp hardware
or wires which are left in place. Frequent follow-up with the surgeon
is necessary to gauge healing and recovery. Sometimes, a short period
of intermaxillary fixation or IMF (having the jaw wired shut) is
recommended as a supplemental fracture stabilization method depending on
the type of treatment that is chosen. If intermaxillary fixation (IMF)
alone is chosen, it is usually recommended for about 4 weeks or so.
Vigorous activity or sports are to be avoided during the recovery
period.
Complications of ORIF can involve complications from the surgery itself. Sensory nerves or nerves to the lip can be cut, stretched, or otherwise injured resulting in numbness or paralysis. Holes drilled for screws can injure teeth. This can cause loss of teeth. Just like IMF, if the plates and screws do not hold or are not placed optimally, local infection can occur which can lead to delayed healing, incomplete bone fusion, or even direct bone infection with osteomyelitis. Again, this can be a severe and life threatening problem which can result in loss of portions of the jaw bone. If the plates and screws are put on with the fracture in a sub-optimal position, the teeth may not fit together perfectly. This is called malocclusion and is another complication of the ORIF technique. Although some things can be done to improve malocclusion after plates and screws are put on, in general surgeons try to reduce the fractures as perfectly as possible at the time of the surgical correction of the fracture. Although these problems all sound daunting, in general patients will often choose ORIF approaches to jaw fractures because of the immediacy of function allowable after surgical fixation of the fractured jaw.
Jaw
fractures are serious injuries. Immediate medical attention is
preferred if a jaw fracture is suspected. Management of the fracture
depends on the location and severity of the fracture type. Options for
IMF or ORIF will be in the forefront of the discussion between the
doctor and patient to choose the method of care that will deliver the
best result. COMPLICATIONS
A number of complications can be associated with either IMF or ORIF. In IMF, no incisions are made and no plates and screws are used, but the wires and braces used to stabilize the teeth may damage the teeth either by cutting into the crowns or by causing severe gingivitis of the roots. It is often difficult for patients to clean around the arch bars. The wires used to wire the jaws together can dig into the cheeks and gums. If the IMF is not stable enough, movement at the fracture site may cause the fracture site to either not heal or to become infected. If infection occurs, the infection may spread to the center of the bone and cause a problem called osteomyelitis which is a severe and debilitating infection that may require many weeks of antibiotics and may even result in loss of parts of the mandible. Tooth injury or loss may also occur if this happens. When the jaws are wired shut and if vomiting occurs, aspiration, pneumonia, and even death may occur. One of the major downsides of the IMF approach is that after the jaws are wired shut for about 4 weeks, the temporal mandibular joints will be stiff and if will take a lot of effort on the patient’s part to re-obtain facile use of the jaw.Complications of ORIF can involve complications from the surgery itself. Sensory nerves or nerves to the lip can be cut, stretched, or otherwise injured resulting in numbness or paralysis. Holes drilled for screws can injure teeth. This can cause loss of teeth. Just like IMF, if the plates and screws do not hold or are not placed optimally, local infection can occur which can lead to delayed healing, incomplete bone fusion, or even direct bone infection with osteomyelitis. Again, this can be a severe and life threatening problem which can result in loss of portions of the jaw bone. If the plates and screws are put on with the fracture in a sub-optimal position, the teeth may not fit together perfectly. This is called malocclusion and is another complication of the ORIF technique. Although some things can be done to improve malocclusion after plates and screws are put on, in general surgeons try to reduce the fractures as perfectly as possible at the time of the surgical correction of the fracture. Although these problems all sound daunting, in general patients will often choose ORIF approaches to jaw fractures because of the immediacy of function allowable after surgical fixation of the fractured jaw.
CONCLUSION
REFERERNCES
Textbooks:Murr AH, “Maxillofacial Trauma” in Lalwani AK, ed., Current Diagnosis and Treatment in Otolaryngology-Head and Neck Surgery, Lange Medical Books/McGraw-Hill, New York, 2004, pp. 209-220.
Articles:
1. Ellis E 3rd, Miles BA. Fractures of the mandible: a technical perspective. Plast Reconstr Surg. 2007 Dec;120(7 Suppl 2):76S-89S. Review. PMID: 18090731
2. Fox AJ, Kellman RM. Mandibular angle fractures: two-miniplate fixation and complications. Arch Facial Plast Surg. 2003 Nov-Dec;5(6):464-9. PMID: 14623682
3. Biller JA, Pletcher SD, Goldberg AN, Murr AH. Complications and the time to repair of mandible fractures. Laryngoscope. 2005 May;115(5):769-72. PMID: 15867637
4. Murr AH. Mandibular angle fractures and noncompression plating techniques. Arch Otolaryngol Head Neck Surg. 2005 Feb;131(2):166-8. No abstract available. PMID: 15723951