Mandibular fracture, also known as fracture of the jaw, is a

break Break or Breaks or The Break may refer to: Time off from duties * Recess (break), time in which a group of people is temporarily dismissed from its duties * Break (work), time off during a shift/recess ** Coffee break, a short mid-morning rest ...

through the

mandibular bone In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...

. In about 60% of cases the break occurs in two places. It may result in a decreased ability to fully open the mouth. Often the teeth will not feel properly aligned or there may be bleeding of the gums. Mandibular fractures occur most commonly among males in their 30s. Mandibular fractures are typically the result of

trauma Trauma most often refers to: * Major trauma, in physical medicine, severe physical injury caused by an external source * Psychological trauma, a type of damage to the psyche that occurs as a result of a severely distressing event *Traumatic i ...

. This can include a fall onto the chin or a hit from the side. Rarely they may be due to

osteonecrosis Avascular necrosis (AVN), also called osteonecrosis or bone infarction, is death of bone tissue due to interruption of the blood supply. Early on, there may be no symptoms. Gradually joint pain may develop which may limit the ability to move. Co ...

tumors A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

in the bone. The most common area of fracture is at the

condyle A condyle (;Entry "condyle"
in
plain X-ray Projectional radiography, also known as conventional radiography, is a form of radiography and medical imaging that produces two-dimensional images by X-ray, x-ray radiation. The image acquisition is generally performed by radiographers, and the i ...

, modern

CT scan A computed tomography scan (CT scan; formerly called computed axial tomography scan or CAT scan) is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers ...

s are more accurate. Immediate surgery is not necessarily required. Occasionally people may go home and follow up for surgery in the next few days. A number of surgical techniques may be used including maxillomandibular fixation and

open reduction internal fixation Internal fixation is an operation in orthopedics that involves the surgical implementation of implants for the purpose of repairing a bone, a concept that dates to the mid-nineteenth century and was made applicable for routine treatment in the m ...

(ORIF). People are often put on

antibiotics An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention o ...

such as

penicillin Penicillins (P, PCN or PEN) are a group of β-lactam antibiotics originally obtained from ''Penicillium'' moulds, principally '' P. chrysogenum'' and '' P. rubens''. Most penicillins in clinical use are synthesised by P. chrysogenum using ...

for a brief period of time. The evidence to support this practice; however, is poor.

Signs and symptoms

General

By far, the two most common symptoms described are pain and the feeling that teeth no longer correctly meet (traumatic malocclusion, or disocclusion). The teeth are very sensitive to pressure (

proprioception Proprioception ( ), also referred to as kinaesthesia (or kinesthesia), is the sense of self-movement, force, and body position. It is sometimes described as the "sixth sense". Proprioception is mediated by proprioceptors, mechanosensory neurons ...

), so even a small change in the location of the teeth will generate this sensation. People will also be very sensitive to touching the area of the jaw that is broken, or in the case of

condylar A condyle (;Entry "condyle"
in
tragus of the

ear An ear is the organ that enables hearing and, in mammals, body balance using the vestibular system. In mammals, the ear is usually described as having three parts—the outer ear, the middle ear and the inner ear. The outer ear consists of ...

. Other symptoms may include loose teeth (teeth on either side of the fracture will feel loose because the fracture is mobile), numbness (because the

inferior alveolar nerve The inferior alveolar nerve (IAN) (also the inferior dental nerve) is a branch of the mandibular nerve, which is itself the third branch of the trigeminal nerve. The inferior alveolar nerves supply sensation to the lower teeth. Structure The in ...

runs along the jaw and can be compressed by a fracture) and

trismus Trismus, commonly called ''lockjaw'' as associated with tetanus, is a condition of limited jaw mobility. It may be caused by spasm of the muscles of mastication or a variety of other causes. Temporary trismus occurs much more frequently than perma ...

(difficulty opening the mouth). Outside the mouth, signs of swelling, bruising and deformity can all be seen. Condylar fractures are deep, so it is rare to see significant swelling although, the trauma can cause fracture of the bone on the anterior aspect of the

external auditory meatus The ear canal (external acoustic meatus, external auditory meatus, EAM) is a pathway running from the outer ear to the middle ear. The adult human ear canal extends from the pinna to the eardrum and is about in length and in diameter. Struc ...

so bruising or bleeding can sometimes be seen in the ear canal. Mouth opening can be diminished (less than 3 cm). There can be numbness or altered sensation (

anesthesia Anesthesia is a state of controlled, temporary loss of sensation or awareness that is induced for medical or veterinary purposes. It may include some or all of analgesia (relief from or prevention of pain), paralysis (muscle relaxation), ...

paraesthesia Paresthesia is an abnormal sensation of the skin (tingling, pricking, chilling, burning, numbness) with no apparent physical cause. Paresthesia may be transient or chronic, and may have any of dozens of possible underlying causes. Paresthesias ar ...

in the chin and lower lip (the distribution of the

mental nerve The mental nerve is a sensory nerve of the face. It is a branch of the posterior trunk of the inferior alveolar nerve, itself a branch of the mandibular nerve (CN V3), itself a branch of the trigeminal nerve (CN V). It provides sensation to the ...

). Intraorally, if the fracture occurs in the tooth bearing area, a step may seen between the teeth on either side of the fracture or a space can be seen (often mistaken for a lost tooth) and bleeding from the gingiva in the area. There can be an

open bite Open bite is a type of orthodontic malocclusion which has been estimated to occur in 0.6% of the people in the United States. This type of malocclusion has no vertical overlap or contact between the anterior incisors. The term "open bite" was coine ...

where the lower teeth, no longer meet the upper teeth. In the case of a

unilateral __NOTOC__ Unilateralism is any doctrine or agenda that supports one-sided action. Such action may be in disregard for other parties, or as an expression of a commitment toward a direction which other parties may find disagreeable. As a word, ''un ...

condylar fracture the back teeth on the side of the fracture will meet and the open bite will get progressively greater towards the other side of the mouth. Sometimes bruising will develop in the floor of the mouth (sublingual

eccymosis A bruise, also known as a contusion, is a type of hematoma of tissue, the most common cause being capillaries damaged by trauma, causing localized bleeding that extravasates into the surrounding interstitial tissues. Most bruises occur close e ...

) and the fracture can be moved by moving either side of the fracture segment up and down. For fractures that occur in the non-tooth bearing area (condyle, ramus, and sometimes the angle) an open bite is an important clinical feature since little else, other than swelling, may be apparent.

Condylar

This type of fractured mandible can involve one condyle (unilateral) or both (bilateral). Unilateral condylar fracture may cause restricted and painful jaw movement. There may be swelling over the temporomandibular joint region and bleeding from the ear because of lacerations to the external auditory meatus. The hematoma may spread downwards and backwards behind the ear, which may be confused with

Battle's sign Battle's sign, also known as mastoid ecchymosis, is an indication of fracture of middle cranial fossa of the skull. These fractures may be associated with underlying brain trauma. Battle's sign consists of bruising over the mastoid process as a re ...

(a sign of a base of

skull fracture A skull fracture is a break in one or more of the eight bones that form the cranial portion of the human skull, skull, usually occurring as a result of blunt force trauma. If the force of the impact is excessive, the bone may fracture at or near ...

), although this is an uncommon finding so if present, intra-cranial injury must be ruled out. If the bones fracture and overlie each other there may be shortening of the height of the ramus. This results in gagging of the teeth on the fractured side (the teeth meet too soon on the fractured side, and not on the non fractured side, i.e. "open bite" that becomes progressively worse to the unaffected side). When the mouth is opened, there may be deviation of the mandible towards the fractured side. Bilateral condylar fractures may cause the above signs and symptoms, but on both sides. Malocclusion and restricted jaw movement are usually more severe. Bilateral body or parasymphysis fractures are sometimes termed "flail mandible", and can cause involuntary posterior movement of the tongue with subsequent obstruction of the upper airway. Displacement of the condyle through the roof of the

glenoid fossa The glenoid fossa of the scapula or the glenoid cavity is a bone part of the shoulder. The word ''glenoid'' is pronounced or (both are common) and is from el, gléne, "socket", reflecting the shoulder joint's ball-and-socket form. It is a sha ...

and into the

middle cranial fossa The middle cranial fossa, deeper than the anterior cranial fossa, is narrow medially and widens laterally to the sides of the skull. It is separated from the posterior fossa by the clivus and the petrous crest. It is bounded in front by the pos ...

is rare. Other rare complications of mandibular trauma include

internal carotid artery The internal carotid artery (Latin: arteria carotis interna) is an artery in the neck which supplies the anterior circulation of the brain. In human anatomy, the internal and external carotids arise from the common carotid arteries, where these b ...

injury, and obliteration of the ear canal due to posterior condylar dislocation. Bilateral condylar fractures combined with a symphyseal fracture is sometimes termed a guardsman's fracture. The name comes from this injury occurring in soldiers who faint on parade grounds and strike the floor with their chin.

Diagnosis

Plain film radiography

Traditionally, plain films of the mandible would be exposed but had lower sensitivity and specificity owing to overlap of structures. Views included AP (for parasymphsis), lateral oblique (body, ramus, angle, coronoid process) and Towne's (condyle) views. Condylar fractures can be especially difficult to identify, depending on the direction of condylar displacement or dislocation so multiple views of it are usually examined with two views at perpendicular angles.

Panoramic radiography

Panoramic radiograph A panoramic radiograph is a panoramic scanning dental X-ray of the upper and lower jaw. It shows a two-dimensional view of a half-circle from ear to ear. Panoramic radiography is a form of focal plane tomography; thus, images of multiple pl ...

s are tomograms where the mandible is in the focal trough and show a flat image of the mandible. Because the curve of the mandible appears in a 2-dimensional image, fractures are easier to spot leading to an accuracy similar to CT except in the condyle region. In addition, broken, missing or malaligned teeth can often be appreciated on a panoramic image which is frequently lost in plain films. Medial/lateral displacement of the fracture segments and especially the condyle are difficult to gauge so the view is sometimes augmented with plain film radiography or

computed tomography A computed tomography scan (CT scan; formerly called computed axial tomography scan or CAT scan) is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers ...

for more complex mandible fractures.

Computed tomography

Computed tomography A computed tomography scan (CT scan; formerly called computed axial tomography scan or CAT scan) is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers ...

is the most sensitive and specific of the imaging techniques. The facial bones can be visualized as slices through the skeletal in either the axial, coronal or

sagittal The sagittal plane (; also known as the longitudinal plane) is an anatomical plane that divides the body into right and left sections. It is perpendicular to the transverse and coronal planes. The plane may be in the center of the body and divid ...

planes. Images can be reconstructed into a 3-dimensional view, to give a better sense of the displacement of various fragments. 3D reconstruction, however, can mask smaller fractures owing to volume averaging, scatter artifact and surrounding structures simply blocking the view of underlying areas. Research has shown that panoramic radiography is similar to computed tomography in its diagnostic accuracy for mandible fractures and both are more accurate than plain film radiograph. The indications to use CT for mandible fracture vary by region, but it does not seem to add to diagnosis or treatment planning except for comminuted or avulsive type fractures, although, there is better clinician agreement on the location and absence of fractures with CT compared to panoramic radiography. File:Simple mandible fracture.jpg, Panoramic radiograph of a simple mandible fracture of the right mandibular body, minimally displaced. Note that the teeth to the left of the fracture do not touch Image:Fracturef mandible.PNG, lateral oblique image demonstrating a fractured mandible. File:Townes view bilateral condyle fracture.jpg, Towne's view of a bilateral condyle fracture. White arrow is a fracture on the neck of the condyle. Black arrow shows the condyle pulled to the medial. The same injury can be seen on the opposite side File:3D CT mandible fracture.jpg, 3D CT reconstruction of mandible fracture, white arrow marks fracture, red arrow marks moderate displacement and open bite File:Occlusal view symphsis fracture.jpg, occlusal radiograph of a mandibular parasymphysis fracture

Classification

There are various classification systems of mandibular fractures in use.

Location

$Mandbular fractures$ This is the most useful classification, because both the signs and symptoms, and also the treatment are dependent upon the location of the fracture. The mandible is usually divided into the following zones for the purpose of describing the location of a fracture (see diagram): condylar, coronoid process, ramus, angle of mandible, body (molar and premolar areas), parasymphysis and symphysis.

=Alveolar

= This type of fracture involves the

alveolus Alveolus (; pl. alveoli, adj. alveolar) is a general anatomical term for a concave cavity or pit. Uses in anatomy and zoology * Pulmonary alveolus, an air sac in the lungs ** Alveolar cell or pneumocyte ** Alveolar duct ** Alveolar macrophage * Mam ...

, also termed the alveolar process of the mandible.

=Condylar

= Condylar fractures are classified by location compared to the capsule of ligaments that hold the

temporomandibular joint In anatomy, the temporomandibular joints (TMJ) are the two joints connecting the jawbone to the skull. It is a bilateral synovial articulation between the temporal bone of the skull above and the mandible below; it is from these bones that it ...

( intracapsular or extracapsular), dislocation (whether or not the condylar head has come out of the socket (glenoid fossa) as the muscles ( lateral pterygoid) tend to pull the condyle

anterior Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

and medial) and neck of the condyle fractures. E.g. extracapsular, non-displaced, neck fracture. Pediatric condylar fractures have special protocols for management.

=Coronoid

= Because the

coronoid process of the mandible In human anatomy, the mandible's coronoid process (from Greek ''korōnē'', denoting something hooked) is a thin, triangular eminence, which is flattened from side to side and varies in shape and size. Its anterior border is convex and is continuou ...

lies deep to many structures, including the zygomatic complex (ZMC), it is rare to be broken in isolation. It usually occurs with other mandibular fractures or with fracture of the zygomatic complex or

arch An arch is a vertical curved structure that spans an elevated space and may or may not support the weight above it, or in case of a horizontal arch like an arch dam, the hydrostatic pressure against it. Arches may be synonymous with vaul ...

. Isolated fractures of the coronoid process should be viewed with suspicion and fracture of the ZMC should be ruled out.

=Ramus

= Ramus fractures are said to involve a region inferiorly bounded by an oblique line extending from the lower

third molar A third molar, commonly called wisdom tooth, is one of the three molars per quadrant of the human dentition. It is the most posterior of the three. The age at which wisdom teeth come through ( erupt) is variable, but this generally occurs betwe ...

(wisdom tooth) region to the posteroinferior attachment of the masseter muscle, and which could not be better classified as either condylar or coronoid fractures.

=Angle

= The angle of the mandible refers to the angle created by the arrangement of the body of the mandible and the ramus. Angle fractures are defined as those that involve a triangular region bounded by the anterior border of

masseter muscle In human anatomy, the masseter is one of the muscles of mastication. Found only in mammals, it is particularly powerful in herbivores to facilitate chewing of plant matter. The most obvious muscle of mastication is the masseter muscle, since it ...

and an oblique line extending from the lower

(wisdom tooth) region to the posteroinferior attachment of the masseter muscle.

=Body

= Fractures of the mandibular body are defined as those that involve a region bounded anteriorly by the parasymphysis (defined as a vertical line just distal to the

canine tooth In mammalian oral anatomy, the canine teeth, also called cuspids, dog teeth, or (in the context of the upper jaw) fangs, eye teeth, vampire teeth, or vampire fangs, are the relatively long, pointed teeth. They can appear more flattened however ...

) and posteriorly by the anterior border of the masseter muscle.

=Parasymphysis

= Parasymphyseal fractures are defined as mandibular fractures that involve a region bounded bilaterally by vertical lines just distal to the canine tooth.

=Symphysis

= Symphyseal fractures are a linear fractures that run in the midline of the mandible (the symphysis).

Fracture type

Mandibular fractures are also classified according to categories that describe the condition of the bone fragments at the fracture site and also the presence of communication with the external environment.

=Greenstick

Greenstick fracture A greenstick fracture is a fracture in a young, soft bone in which the bone bends and breaks. Greenstick fractures occur most often during infancy and childhood when bones are soft. The name is by analogy with green (i.e., fresh) wood which simil ...

s are incomplete fractures of flexible bone, and for this reason typically occur only in children. This type of fracture generally has limited mobility.

=Simple

= A simple fracture describes a complete transection of the bone with minimal fragmentation at the fracture site.

=Comminuted

= The opposite of a simple fracture is a comminuted fracture, where the bone has been shattered into fragments, or there are secondary fractures along the main fracture lines. High velocity injuries (e.g. those caused by bullets,

improvised explosive devices An improvised explosive device (IED) is a bomb constructed and deployed in ways other than in conventional military action. It may be constructed of conventional military explosives, such as an artillery shell, attached to a detonating mechan ...

, etc...) will frequently cause comminuted fractures.

=Compound

= A compound fracture is one that communicates with the external environment. In the case of mandibular fractures, communication may occur through the skin of the face or with the oral cavity. Mandibular fractures that involve the tooth-bearing portion of the jaw are by definition compound fractures, because there is at least a communication via the periodontal ligament with the oral cavity and with more displaced fractures there may be frank tearing of the gingival and

alveolar mucosa The oral mucosa is the mucous membrane lining the inside of the mouth. It comprises stratified squamous epithelium, termed "oral epithelium", and an underlying connective tissue termed ''lamina propria''. The oral cavity has sometimes been describ ...

Involvement of teeth

When a fracture occurs in the

tooth A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ...

bearing portion of the mandible, whether or not it is dentate or edentulous will affect treatment. Wiring of the teeth helps stabilize the fracture (either during placement of

osteosynthesis Internal fixation is an operation in orthopedics that involves the surgical implementation of implants for the purpose of repairing a bone, a concept that dates to the mid-nineteenth century and was made applicable for routine treatment in the m ...

or as a treatment by itself), so the lack of teeth will guide treatment. When an edentulous mandible (no teeth) is less than 1 cm in height (as measured on

panoramic radiograph A panoramic radiograph is a panoramic scanning dental X-ray of the upper and lower jaw. It shows a two-dimensional view of a half-circle from ear to ear. Panoramic radiography is a form of focal plane tomography; thus, images of multiple pl ...

) additional risks apply because the blood flow from the marrow (endosseous) is minimal and the healing bone must rely on blood supply from the

periosteum The periosteum is a membrane that covers the outer surface of all bones, except at the articular surfaces (i.e. the parts within a joint space) of long bones. Endosteum lines the inner surface of the medullary cavity of all long bones. Structure ...

surrounding the bone. If a fracture occurs in a child with mixed dentition different treatment protocols are needed. Other fractures of the body, are classified as open or closed. Because fractures that involve the teeth, by definition, communicate with the mouth this distinction is largely lost in mandible fractures. Condylar, ramus, and coronoid process fractures are generally closed whereas angle, body and parasymphsis fractures are generally open. $Multiple mandible fractures$

Displacement

The degree to which the segments are separated. The larger the separation, the more difficult it is to bring them back together (approximate the segments)

Favourability

For angle and posterior body fractures, when the angle of the fracture line is angled back (more posterior at the top of the jaw and more

at the bottom of the jaw) the muscles tend to bring the fracture segments together. This is called favorable. When the angle of the fractures is pointing to the front, it is unfavorable.

Age of the fracture

While mandible fractures have similar complication rates whether treated immediately or days later, older fractures are believed to have higher non-union and infection rates although the data on this makes it difficult to draw firm conclusions.

Treatment

Like all fractures, consideration has to be given to other illnesses that might jeopardize the patient, then to reduction and fixation of the fracture itself. Except in avulsive type injuries, or those where there might be airway compromise, a several day delay in the treatment of mandible fractures seems to have little impact on the outcome or complication rates.

General considerations

Since mandible fractures are usually the result of blunt force trauma to the head and face, other injuries need to be considered before the mandible fracture. First and foremost is compromise of the airway. While rare, bilateral mandible fractures that are unstable can cause the tongue to fall back and block the airway. Fractures such as a symphyseal or bilateral parasymphyseal may lead to mobility of the central portion of the mandible where

genioglossus The genioglossus is one of the paired extrinsic muscles of the tongue. The genioglossus is the major muscle responsible for protruding (or sticking out) the tongue. Structure Genioglossus is the fan-shaped extrinsic tongue muscle that forms the ma ...

attaches, and allow the tongue to fall backwards and block the airway. In larger fractures, or those from high velocity injuries, soft tissue swelling can block the airway. In addition to the potential for airway compromise, the force delivered to break the jaw can be great enough to either fracture the

cervical spine In tetrapods, cervical vertebrae (singular: vertebra) are the vertebrae of the neck, immediately below the skull. Truncal vertebrae (divided into thoracic and lumbar vertebrae in mammals) lie caudal (toward the tail) of cervical vertebrae. In sau ...

or cause intra-cranial injury (

head injury A head injury is any injury that results in trauma to the skull or brain. The terms ''traumatic brain injury'' and ''head injury'' are often used interchangeably in the medical literature. Because head injuries cover such a broad scope of inju ...

). It is common for both to be assessed with facial fractures. Finally, vascular injury can result (with particular attention to the

internal carotid The internal carotid artery (Latin: arteria carotis interna) is an artery in the neck which supplies the anterior circulation of the brain. In human anatomy, the internal and external carotids arise from the common carotid arteries, where these b ...

and jugular) from high velocity injuries or severely displaced mandible fractures. Loss of consciousness combined with aspiration of tooth fragments, blood and possibly

denture Dentures (also known as false teeth) are prosthetic devices constructed to replace missing teeth, and are supported by the surrounding soft and hard tissues of the oral cavity. Conventional dentures are removable (removable partial denture or ...

s mean that the airway may be threatened.

Reduction

Reduction refers to approximating the ends of the bones edges that are broken. This is done with either an open technique, where an incision is made, the fracture is found and is physically manipulated into place, or closed technique where no incision is made. The mouth is unique, in that the teeth are well secured to the bone ends but come through epithelium (mucosa). A leg or wrist, for instance, has no such structure to help with a closed reduction. In addition, when the fracture happens to be in a tooth bearing area of the jaws, aligning the teeth well usually results in alignment of the fracture segments. To align the teeth, circumdental wiring is often used where wire strands (typically 24 gauge or 26 gauge) are wrapped around each tooth then attached to a stainless steel arch bar. When the maxillary (top) and mandibular (bottom) teeth are aligned together, this brings the fracture segments into place. Higher tech solutions are also available, to help reduce the segments with arch bars using bonding technology.

Fixation

Simple fractures are usually treated with closed reduction and indirect skeletal fixation, more commonly referred to as maxillo-mandibular fixation (MMF). The closed reduction is explained above. The indirect skeletal fixation is accomplished by placing an arch bar, secured to the teeth on the maxillary and mandibular dentition, then securing the top and bottom arch bars with wire loops. Many alternatives exist to secure the maxillary and mandibular dentition including resin bonded arch bars, Ivy loops (small eyelets of wires), orthodontic bands and MMF bone screws where titanium screws with holes in the head of them are screwed into the basal bone of the jaws then secured with wire. Closed reduction with direct skeletal fixation follows the same premise as MMF except that wires are passed through the skin and around the bottom jaw in the mandibule and through the piriform rim or zygomatic buttresses of the maxilla then joined to secure the jaws. The option is sometimes used when a patient is edentulous (has no teeth) and rigid internal fixation cannot be used. Open reduction with direct skeletal fixation allows the bones to be directly mandibulated through an incision so that the fractured ends meet, then they can be secured together either rigidly (with screws or plates and screws) or non-rigidly (with transosseous wires). There are a multitude of various plate and screw combinations including compression plates, non-compression plates, lag-screws, mini-plates and biodegradable plates. External fixation, which can be used with either open or closed reduction uses a pin system, where long screws are passed through the skin and into either side of a fracture segment (typically 2 pins per side) then secured in place using an external fixator. This is a more common approach when the bone is heavily comminuted (shattered into small pieces, for instance in a bullet wound) and when the bone is infected (

osteomyelitis Osteomyelitis (OM) is an infection of bone. Symptoms may include pain in a specific bone with overlying redness, fever, and weakness. The long bones of the arms and legs are most commonly involved in children e.g. the femur and humerus, while the ...

). Regardless of the method of fixation, the bone need to remain relatively stable for a period of 3–6 weeks. On average, the bone gains 80% of its strength by 3 weeks and 90% of it by 4 weeks. There is great variation depending on the severity of injury, health of the wound, and age of the patient.
File:Maxillomandibularfixation.jpg, Maxillomandibular fixation with circumdental wires, archbars and elastics for a condyle fracture File:Rigid Internal fixation mandible.jpg, Rigid internal fixation of parasymphysis fracture of the mandible. White arrow marks fracture, black arrow marks arch bar on lower teeth File:Rigid Internal fixation mandible condyle.jpg, Rigid internal fixation of right condyle fracture with mini-plate on the neck of the condyle. Black arrow marks right earlobe, white arrow marks head of the condyle File:External fixation mandible.jpg, External fixation of left mandible fracture

Current clinical evidence

A 2013

Cochrane review Cochrane (previously known as the Cochrane Collaboration) is a British international charitable organisation formed to organise medical research findings to facilitate evidence-based choices about health interventions involving health professi ...

assessed clinical studies on surgical (open reduction) and non-surgical (closed reduction) management of mandible fractures that do not involve the condyle. The review found insufficient evidence to recommend the effectiveness of any single intervention.

Special considerations

Condyle

The best treatment for condylar fractures is controversial. There are two main options, namely closed reduction or open reduction and fixation. Closed reduction may involve intermaxillary fixation, where the jaws are splinted together in the correct position for a period of weeks. Open reduction involves surgical exposure of the fracture site, which can be carried out via incisions within the mouth or incisions outside the mouth over the area of the condyle. Open reduction is sometimes combined with use of an

endoscope An endoscope is an inspection instrument composed of image sensor, optical lens, light source and mechanical device, which is used to look deep into the body by way of openings such as the mouth or anus. A typical endoscope applies several modern t ...

to aid visualization of fracture site. Although closed reduction carries a risk of the bone healing out of position, with consequent alteration of the bite or the creation of facial asymmetry, it does not risk temporary damage to the

facial nerve The facial nerve, also known as the seventh cranial nerve, cranial nerve VII, or simply CN VII, is a cranial nerve that emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of tas ...

or result in any facial scar that accompanies open reduction. A

systematic review A systematic review is a Literature review, scholarly synthesis of the evidence on a clearly presented topic using critical methods to identify, define and assess research on the topic. A systematic review extracts and interprets data from publ ...

was unable to find sufficient evidence of the superiority of one method over another in the management of condylar fractures. Paediatric condylar fractures are especially problematic, owing to the remaining growth potential and possibility of ankylosis of the joint. Early mobilization is often recommended as in the Walker protocol.

Edentulous mandible

A broken jaw that has no teeth in it faces two additional issues. First, the lack of teeth makes reduction and fixation using MMF difficult. Instead of placing circumdental wires around the teeth, existing dentures can be left in (or Gunning splints, a type of temporary denture) and the mandible fixated to the maxilla using skeletal fixation (circummandibular and circumzygomatic wires) or using MMF bone screws. More commonly, open reduction and rigid internal fixation is placed. When the width of the mandible is less than 1 cm, the jaw loses its

endosteal The endosteum (plural endostea) is a thin vascular membrane of connective tissue that lines the inner surface of the bony tissue that forms the medullary cavity of long bones. This endosteal surface is usually resorbed during long periods of ma ...

blood supply. Instead, the blood supply comes largely from the

. Open reduction (which normally strips the periosteum during the dissection) can lead to

avascular necrosis Avascular necrosis (AVN), also called osteonecrosis or bone infarction, is death of bone tissue due to interruption of the blood supply. Early on, there may be no symptoms. Gradually joint pain may develop which may limit the ability to move. Co ...

. In these cases, oral surgeons sometimes opt for external fixation, closed reduction, supraperiosteal dissection or other techniques to maintain the periosteal blood flow.

High velocity injuries

In high velocity injuries, the soft tissue can be severely damaged far from the bullet wound itself due to

hydrostatic shock Hydrostatic shock is the controversial concept that a penetrating projectile (such as a bullet) can produce a pressure wave that causes "remote neural damage", "subtle damage in neural tissues" and/or "rapid incapacitating effects" in living ta ...

. Because of this the airway must be carefully managed and vessels well examined. Because the jaw can be highly comminuted, MMF and rigid internal fixation can be difficult. Instead,

external fixation External fixation is a surgical treatment wherein rods are screwed into bone and exit the body to be attached to a stabilizing structure on the outside of the body. It is an alternative to internal fixation, where the components used to provide st ...

is often used^,.

Pathologic fracture

Fractures where large

cysts A cyst is a closed sac, having a distinct envelope and division compared with the nearby tissue. Hence, it is a cluster of cells that have grouped together to form a sac (like the manner in which water molecules group together to form a bubble) ...

tumours A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

are in the area (and weaken the jaw), where there is an area of

or where

exist cause special challenges to fixation and healing. Cysts and tumours can limit effective bone to bone contact and osteomyelitis or osteonecrosis compromise blood supply to the bone. In all of the situations, healing will be delayed and sometimes, resection is the only alternative to treatment.

Prognosis

The healing time for a routine mandible fractures is 4–6 weeks whether MMF or rigid internal fixation (RIF) is used. For comparable fractures, patients who received MMF will lose more weight and take longer to regain mouth opening, whereas, those who receive RIF have higher

infection An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable dise ...

rates. The most common long-term complications are loss of sensation in the

mandibular nerve In neuroanatomy, the mandibular nerve (V) is the largest of the three divisions of the trigeminal nerve, the fifth cranial nerve (CN V). Unlike the other divisions of the trigeminal nerve (ophthalmic nerve, maxillary nerve) which contain only aff ...

, malocclusion and loss of teeth in the line of fracture. The more complicated the fracture (infection, comminution, displacement) the higher the risk of fracture. Condylar fractures have higher rates of malocclusion which in turn are dependent on the degree of displacement and/or dislocation. When the fracture is intracapsular there is a higher rate of late-term osteoarthritis and the potential for ankylosis although the later is a rare complication as long as mobilization is early. Pediatric condylar fractures have higher rates of ankylosis and the potential for growth disturbance.^, Rarely, mandibular fracture can lead to Frey's syndrome.

Epidemiology

Mandible fracture causes vary by the time period and the region studied. In North America, blunt force trauma (a punch) is the leading cause of mandible fracture whereas in India, motor vehicle collisions are now a leading cause. On battle grounds, it is more likely to be high velocity injuries (bullets and shrapnel). Prior to the routine use of seat belts, airbags and modern safety measures, motor vehicle collisions were a leading cause of facial trauma. The relationship to blunt force trauma explains why 80% of all mandible fractures occur in males. Mandibular fracture is a rare complication of third molar removal, and may occur during the procedure or afterwards. With respect to trauma patients, roughly 10% have some sort of facial fracture, the majority of which come from motor vehicle collisions. When the person is unrestrained in a car, the risk of fracture rises 50% and when an unhelmeted motorcyclist the risk rises 4-fold.

History

Management of mandible fractures has been mentioned as early as 1700 B.C. in the

Edwin Smith Papyrus The Edwin Smith Papyrus is an ancient Egyptian medical text, named after Edwin Smith who bought it in 1862, and the oldest known surgical treatise on trauma. From a cited quotation in another text, it may have been known to ancient surgeons as t ...

and later by

Hippocrates Hippocrates of Kos (; grc-gre, Ἱπποκράτης ὁ Κῷος, Hippokrátēs ho Kôios; ), also known as Hippocrates II, was a Greek physician of the classical period who is considered one of the most outstanding figures in the history of ...

in 460 B.C., "Displaced but incomplete fractures of the mandible where continuity of the bone is preserved should be reduced by pressing the lingual surface with the fingers...". Open reduction was described as early as 1869. Since the late 19th century, modern techniques including MMF (see above) have been described with titanium based rigid internal fixation becoming commonplace since the 1970s and biodegradable plates and screws being available since the 1980s.

References

External links

{{Fractures Bone fractures Jaw disorders Wikipedia medicine articles ready to translate Wikipedia emergency medicine articles ready to translate