Mandibular fracture

A mandibular fracture ( fracture of the mandible lat, fracture of the mandible ossis, Mandibularfraktur or fracture of the mandible, Eng. Mandibular fracture ) is a fracture of the mandible. The mandibular fracture has typical curves of the fracture lines that run along weaknesses of the mandible. The fracture can occur inside or outside the row of teeth. The classification of mandibular fractures is carried out on the basis of the relevant anatomical structures.

  • 5.1 examination and clinical diagnosis
  • 5.2 X-ray examination
  • 5.3 Differential Diagnosis
  • 7.1 Initial treatment
  • 7.2 operation
  • 7.3 reduction
  • 7.4 Technology of operative fixation
  • 7.5 intermaxillary fixation

Anatomical bases

The lower jaw ( mandible ) is a horseshoe-shaped bone ( mandibular ) with both sides ascending ramus ( ramus ), which results from the muscle attachment of the temporalis muscle ( coronoid process ) and the articular process ( condylar process ) with the mandibular condyle ( head of the mandible ) composed. The tooth-bearing part of the mandible ( alveolar ) interacts with the upper row of teeth, which he has influenced the occlusion and therefore also affect the position of the mandible.

The Unterkieferwulst forms in the 4th to 5th week of embryonic development from the first pharyngeal arch. The Merkel - cartilage - one belonging to the first pharyngeal arch cartilage clasp - also known as mandibular arch and forms except for two small portions ( incus and malleus ) in the dorsal region completely back. From the mesenchyme of Unterkieferwulstes most of the later, definitive mandibular bone develops by intramembranous ossification. Only a small share in the fusion zone of both cartilages ossified enchondral.

Causes of mandibular fracture

Mandibular fractures often result from blunt force, which acts with high energy on the lower jaw. Typical causes of these traumas are traffic accidents ( car, motorcycle, bicycle), sports accidents slashed disputes (very common punches ), fall from height and falls. Are rarer in Germany mandibular fractures due to gunshot wound.

Frequency

Of the approximately 70% of facial fractures are fractures of the mandible, with the numbers and the distribution of frequencies may vary ( trauma surgery clinic, dental clinic or oral and maxillofacial surgery clinic ) widely depending on the source of the survey.

Classification

The mandibular fracture is one of the fractures of the face and is based senior anatomical structures divided into:

  • Condylar fractures (25-30 %)
  • Mandibular angle fractures (20-25 %)
  • Fractures in the symphysis (15-20 %)
  • Fractures of the alveolar ridge (20-30%) Fractures in the canine area (5-10%)
  • Fractures in the premolars (approx. 10%)
  • Fractures in the molars (7-9 %)

In the clinic, a classification has been established on the basis of therapeutic point of view.

Review the classification of mandibular fracture classification

In today's clinical practice found no classification that combines both anatomic, clinical and therapeutic aspects.

  • Simple fracture with closed soft tissue coverage
  • Complicated fracture with Weichteilperforation
  • Incomplete fracture
  • Subperiosteal fracture ( " greenstick fracture " )
  • Complete fracture
  • Multiple fracture
  • Debris or defect fracture
  • Alveolar ( alveolar process )
  • Median and paramedian pine body
  • Canine and posterior teeth

Outside the row of teeth

  • In the field or behind the tooth socket of the last tooth
  • Angle of the jaw
  • Ascending ramus
  • Articular process ( condylar process )
  • Edentulous mandible

Diagnosis

Examination and clinical diagnosis

One differentiates clinical and radiological signs of fracture in the fracture characters. The detection of mandibular fracture in a purely cosmetic consideration is the facial soft tissue, bruises, abrasions, extensive bleeding and bruising complicated by postoperative occurring massive swelling (edema ) ( hematoma).

Possible symptoms of mandibular fracture are abnormal mobility of the mandible with missing mouth closure, dislocation of the bone fragment, bone crunching ( crepitus ) during movement of the bone fragment, hematoma, swelling, sensory disturbances ( particularly mental nerve ) compression pain, bleeding, occlusion.

Clinically, the diagnosis is made by the control to safe and unsafe signs of fracture.

  • Dislocation of the bone fragments
  • Crepitation
  • Pathological mobility
  • Visible bone fragments in open fractures or bone gradations
  • Pain
  • Swelling
  • Hematoma
  • Disabilities
  • Sensory disturbances inferior alveolar nerve / mental nerve

X-ray

As the primary diagnostic investigation means simple radiographs are indicated. These include the orthopantomography (OPG ) and the lower jaw radiograph after Clementschitsch. To get a clear idea of ​​the three-dimensional anatomy and extent of the fracture, the radiographs of the various projections have to be compared.

With the computed tomography ( CT), the possibilities for imaging diagnosis of mandibular fractures have improved significantly. The CT often provides the fracture path is accurate and helps in surgical planning. The higher radiation exposure should be taken into account over a simple, conventional X-ray diagnostic.

Differential Diagnosis

The differential diagnosis is to think in the area of the temporomandibular joint always subluxations of teeth, contusions of the temporomandibular joint, dentitio difficiles, hematoma and edema.

Associated injuries

Mandibular fractures occur in both heavy and for light traumas. That is why getting the search for further damage obligatory. Acute life-threatening possible relocation of the respiratory tract may be, for example, by the falling back of the tongue base with double-sided paramedian mandibular fractures. Also, the outer ear canal should be inspected as a traumatic injury of the latter is possible due to the close proximity of the temporomandibular joint and the external auditory canal. A possible indicator of a blood flow from the outer ear canal.

Furthermore, loss of function ( = uncertain fracture character) may serve as clues for the location of the fracture - for example, sensory disturbances in the lower lip, lack of thermal vitality of the mandibular teeth.

Therapy

The treatment of mandibular fracture occurs by reduction, fixation, retention and immobilization. In this case a conservative and surgical therapy is possible. Surgical treatment is performed by an oral and maxillo - facial surgeons or orthopedic surgeons.

Here, the displaced fragment is reduced and fixed by mini-plate osteosynthesis (osteosynthesis ). In the area of the mandibular condyle may be made by interosseäre screws with a stabilization of the fragments. Before the advent of plate osteosynthesis fixation was performed by wire osteosynthesis.

Initial treatment

The accident care must ensure the vital functions first. If the airway can not be exposed, the dislocated mandible fragment must be repositioned emergency basis and a renewed decline of the tongue can be prevented. If this is not possible, perhaps a tracheotomy or cricothyrotomy for airway management must be carried out.

Mandibular fractures are often caused by traumatic events (such as brutality, traffic accidents ) caused and may be accompanied by other, potentially life-threatening injuries. The diagnosis of mandibular fracture is then available during the initial phase of treatment is not in the foreground.

Operation

In the surgical treatment is tried to eliminate the defects, to restore the continuity of the lower jaw bone and to achieve an aesthetic reconstruction of the face. Here we fixed the unstable bone fragments to the stable parts of the mandible. An important goal of therapy is to restore a normal dental occlusion, mastication and speech function.

Since intraoperative occlusion must be checked, is an oral intubation through the mouth of the question. Instead, resorting to nasal intubation or use any existing tracheostomy for intraoperative ventilation.

Reduction

Fragment shifts by muscle pull, which often occur in fractures in the extremities range are also observed for mandibular fractures. It comes through the muscles attached to the mandible to a displacement of the fragments, such as coronoid process with the muscle attachment of the temporalis muscle. This fragment shifts caused by muscle pull can make it difficult to reposition. Furthermore, often occurs a fragment displacement on by the great violence during fracture and the fracture edges can a reduction often stand in the way, as they be strong serrated and may have a complicated three-dimensional course.

Technology of operative fixation

In the surgical treatment, a distinction between a functionally stable and exercise steady supply. For surgical treatment osteosynthesis plates, Miniosteosyntheseplatten, wire suspension and tension screws can be used.

Surgical approach:

  • For paramedian / median mandibular fracture: oral vestibule ( vestibule )
  • For fractures in the tooth-bearing molar region: oral vestibule ( vestibule ), submandibular
  • For fractures in the region of the ascending ramus: oral vestibule ( vestibule ), submandibular, preauricular / retroauricular
  • For fractures of the temporomandibular joint: oral vestibule ( vestibule ), pre-auricular / retroauricular

The aim is mainly an exercise stable splinting ( plate fixation ) of the fragment and the rigid immobilization of the fracture. An exception in this case represent fractures in the area of the temporomandibular joint, where to avoid ankylosis early mobilization is aimed at and the fixation of very small fragments is not always possible.

The best cosmetic results in terms of the scars are obtained by two-layer suture closure to reduce the train on the skin and thus to achieve a smaller scar. The intra-oral sutures are removed after about 10 days, while the extra-oral sutures after about 5-7 days.

Intermaxillary fixation

The intermaxillary fixation (IMF ) of the teeth of the mandible and maxilla may be necessary in the treatment of mandibular fracture. This fixation is performed both preoperatively ( as an emergency measure ) and intraoperatively after reduction and fixation of the fragments.

For the period in which the intermaxillary fixation is carried ( 4-8 weeks ), the normal diet is restricted. On the high-fat and alcoholic foods should be avoided, since vomiting by the IMF carries an increased risk of aspiration of vomit. Initially, the diet of a transnasal feeding tube is secure, if necessary.

Complications

Complications after mandibular fractures may remain permanent deformities.

Despite outright healing " on the radiograph " it can be used for training of nonunions, sensory disturbances in the lower lip and teeth - the mental nerve, lingual nerve, inferior alveolar nerve - come. There is also the risk of infections, which are favored by extended Weichgewebsdefekte, hematoma, open fractures and comminuted fractures.

The best chance of good functional and aesthetic results are given at an early surgical intervention.

Osteotomies

In osteotomies for the conversion of occlusion in mandibular facial deformities, for example after malpositioned healed fractures, or mandibular growth disturbances ( orthognathic surgery ), the transection of the mandible along the external oblique line in the area of ​​second molars and lingual performed above the mandibular foramen. Here there running the mandibular nerve ( inferior alveolar nerve ) is preserved and the anterior drawer -shaped lower jaw fragment moves forward or backward and fixed by means of osteosynthesis plates in the new position. This current practice of surgical method is surgery Obwegeser modified after Dal Pont.

Occlusion (dentistry)
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