Executive Editor: Marcelo Figari, Gregorio Sánchez Aniceto General Editor: Daniel Buchbinder

Authors: Ricardo Cienfuegos, Carl-Peter Cornelius, Edward Ellis III, George Kushner

Mandible - Special considerations

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Glossary

1 Diagnosis top

Infected fractures with or without bone loss enlarge

Definition

Open fractures can generally be regarded as contaminated. Since fractures in the dentate area have communication with the oral cavity, these are considered open fractures.
Infections with clinical relevance show swelling, pain, fever, reddening, and secretion of pus. In the case of acute infection radiographic signs can be absent. Chronic cases exhibit the typical signs of osteomyelitis.

Special conditions influencing adequate internal fixation
Instability produces and maintains the infectious process.

Osteosynthesis of an acutely infected fracture or pseudarthrosis must be a safe procedure. Under these conditions, high rigidity (absolute immobility) is mandatory. Therefore the locking reconstruction system 2.4 is recommended. It is important not to place any screws into the infected bone area which must be spared from screw insertion. The reconstruction plate functions as a bridging device. Large areas of infected or necrotic bone require curettage and either immediate or delayed cancellous bone grafting. Antibiotic therapy alone does not eliminate the infection as long as the fracture is unstable.

Clinical findings
Fractures in the dentate area are regarded as open fractures because the gingiva is usually lacerated. These fractures are contaminated. An acute infection is not reflected in the x-ray examination. In chronic cases the bone becomes infected exhibiting the typical clinical and radiographic signs of osteomyelitis.

In addition there will be inflammatory signs such as swelling, pain, fever, reddening, and secretion of pus.

Clinical photograph showing an infected fracture between the first and second molar. The pericoronal gingiva of the second molar contains pus and the swelling fills the vestibular sulcus.


Infected fractures with or without bone loss enlarge

Imaging

OPG confirming the clinical diagnosis of an infected fracture site in the posterior mandibular body with radiolucency around the second molar and an extended fracture zone containing several bone sequestra.


Infected fractures with or without bone loss enlarge

PA view of the same case.


Infected fractures with or without bone loss enlarge

CT scans of the same patient detailing the condition of the fracture zone.


Additional considerations

Patients with infected fractures often present a constellation of problems:

  • Noncompliance
  • Alcohol addiction
  • Drug abuse
  • Self-neglect and social deprivation
  • Imprisonment
  • Dementia

Medical risk factors:

  • Chronic corticoid medication
  • Immune deficiency
  • Diabetes mellitus
  • Osteopathy

2 Principles top

Infected fractures with or without bone loss enlarge

Formal pathogenesis

A predilection zone for infected fractures is the posterior mandibular body or the angle region. Contributing factors in this area are due to the occurrence of impacted or partially impacted wisdom teeth. The chronic infection leads to osteomyelitis with inflammatory resorption and sequestration of the bone in the proximity of the fracture line.


Infected fractures with or without bone loss enlarge

The current concept is that the infection and osteomyelitis are propagated by the instability and mobility of the fracture fragments.


Infected fractures with or without bone loss enlarge

When dealing with osteomyelitis, the infected fracture will be debrided and leave the patient with a defect fracture situation.


Infected fractures with or without bone loss enlarge

If the bony defect extends throughout the entire fracture, grafting will be necessary.


Choice of implant

Since the rigidity of large plates is defined by the number and diameter of the inserted screws, it is recommended to use reconstruction plates compatible with large diameter screws only, ie, 2.4 or 3.0 mm screws.

The span of the plate has to cover such a length that at least three screws on either side of the defect can be inserted into intact bone. Very often, with large span defects, it is advisable to have four or more screws on either side of the defect.

3 Sequestrectomy and debridement top

Infected fractures with or without bone loss enlarge

Clearing of the infected area

After wide exposure of the outer bony surface the infected area must be cleared of any granulation tissue.
The extent of the exposure must anticipate the application of a large reconstruction plate allowing for the placement of at least three screws on either side away from the defect.


Infected fractures with or without bone loss enlarge

Sequestrectomy

Remove the dead bone (sequestra) and decorticate the bony surfaces of the fractured ends.


Infected fractures with or without bone loss enlarge

Smoothing bony edges

Sharp bony edges should be burred away. The remaining bone surfaces should have bleeding patches to make sure that the vascularization is maintained.
This will define the size of the eventual defect.

The mandibular nerve should be preserved, if not irreversibly damaged by the chronic infectious process.


Infected fractures with or without bone loss enlarge

Tooth and sequestra removed.

4 Load-bearing osteosynthesis top

Infected fractures with or without bone loss enlarge

MMF and preliminary fragment fixation

The tooth bearing distal part of the fracture is secured via MMF. The condyle bearing part is positioned arbitrarily by pushing the condyle into the fossa and a small (adaptation) plate is applied onto the superior border of the defect in order to maintain the position of the fragments while the reconstruction plate is adapted and secured.


Infected fractures with or without bone loss enlarge

Contouring the plate

The load-bearing bridging plate is contoured to the lower border with the help of a malleable template.


Infected fractures with or without bone loss enlarge

The contour of the plate must match the template in all three dimensions.


Infected fractures with or without bone loss enlarge

Click here for a detailed description of the bending procedure.


Infected fractures with or without bone loss enlarge

Plate fixation

The bridging plate is firmly applied to the bone with plate forceps and the screws are inserted in the usual manner, starting with the screws closest to the defect zone.

Click here for a detailed description of screw insertion into locking plates.


Infected fractures with or without bone loss enlarge

Option: remove adaptation plate
After all screws are inserted, optionally, remove the adaptation plate at the superior border of the mandible.


Occlusion check

Load-bearing osteosynthesis is stable and cannot be influenced postoperatively using elastic tractions. Therefore, the occlusion must be checked after applying the plate. If it does not fit it must be decided whether the occlusion can be corrected by minimally grinding the teeth or repositioning of the bone and plate. The revision of the osteosynthesis may be difficult because of reduced quality of the bone and reduced bony buttressing.

Removal of arch bars
Usually, this type of fracture occurs in compromised or noncompliant patients. Therefore, one might consider removal of all MMF appliances prior to intraoral wound closure (at the tooth extraction site). This can facilitate oral hygiene.

5 Intraoral plastic soft-tissue coverage top

Infected fractures with or without bone loss enlarge

The intraoral mucoperiosteum is closed using the envelope technique with a flap derived from the lateral vestibule.
This is done prior to any bone grafting in order to separate the defect from the oral cavity.

6 Same stage bone grafting top

Infected fractures with or without bone loss enlarge

Bone harvesting

If immediate bone grafting is desired, bone is harvested from the anterior iliac crest or the tibial head according to preference and the amount of bone graft needed.

In this case a corticocancellous piece and cancellous chips were taken from the inner table of the iliac crest.


Infected fractures with or without bone loss enlarge

The corticocancellous piece was shaped approximately to the size of the defect. Holes were drilled to increase the bony surface in order to enhance revascularization.


Infected fractures with or without bone loss enlarge

Cancellous chips were harvested to augment and fill in the defect.


Infected fractures with or without bone loss enlarge

Applying the bone graft

All bone grafts are inserted through the external approach.
The shape of the corticocancellous bone graft is checked and introduced into the defect.


Infected fractures with or without bone loss enlarge

The remaining dead space is filled with cancellous chips which are further used to augment the area.

7 Extraoral wound closure top

Infected fractures with or without bone loss enlarge

The use of suction drain is at the discretion of the surgeon. The external wound is closed in layers.

8 Completed osteosynthesis top

Infected fractures with or without bone loss enlarge

Panoramic x-ray showing the plate osteosynthesis bridging the defect zone in the left posterior mandibular body.

Note: there are three screws on each side of the defect and these are placed away from the fracture. The defect zone appears opaque because of the bone graft.

A nasogastric tube is used to feed the patient to enhance intraoral hygiene.

9 Aftercare top

If arch bars or MMF screws are used, they may be removed at the conclusion of surgery or may be maintained for several weeks at the discretion of the surgeon.
Postoperative x-rays are taken within the first days after surgery. In an uneventful course, follow-up x-rays are taken at the 4–6 week interval.
It will be necessary to see the patient after approximately 1 week to assess the stability of the occlusion. In an infected mandibular fracture, the aftercare has to include the observation of a number of factors including the special wound situation, the general health condition (nutritional status, diabetes, and particular medication), psychosocial status, economical situation and specific local regimens. The surgeon must also evaluate patient response to the current antibiotic regimens and check for systemic parameters (for example, CRP, white cell blood count, erythrocyte sedimentation rate). Patients will have to be re-examined periodically to rule out recurring signs of infection. At each visit, the surgeon must evaluate patient ability to perform adequate oral hygiene and wound care. It may be necessary to provide additional instruction to assure appropriate hygiene and wound care.

If a malocclusion is detected, the surgeon must ascertain the etiology of it (using the appropriate imaging technique). If the malocclusion is secondary to surgical edema or muscle splinting, training elastics may be beneficial. The lightest elastics possible are used for guidance, because active motion of the mandible is desirable. Patients should be shown how to place and remove the elastics using a hand mirror.

If the malocclusion is secondary to a bony problem due to inadequate reduction or hardware failure or displacement, elastic training will be of no benefit. The patient must return to the operating room for revision surgery.
Follow-up appointments are at the discretion of the surgeon, and will also depend on the stability of the occlusion noted on the first visit. If a malocclusion is noted and treatable by using training elastics, at weekly appointments to determine the progression are recommended.

Postoperatively, patients will have to follow three basic instructions:

1. Diet
Depending upon the stability of the internal fixation, the diet can vary between liquid and semi-liquid to “as tolerated”, at the discretion of the surgeon. Any elastics are removed during eating.

2. Oral hygiene
Patients having only extraoral approaches are not compromised in their routine oral hygiene measures and should continue with their daily schedule.
Patients with intraoral wounds must be instructed in appropriate oral hygiene procedures. The presence of the arch-bars and any elastics makes this a more difficult procedure than normal. A soft toothbrush (dipping in warm water makes it softer) should be used to clean the surfaces of the teeth and arch-bars. Any elastics are removed for oral hygiene procedures. Chlorhexidine oral rinses should be prescribed and used at least three times each day to help sanitize the mouth. For larger debris, a 1:1 mixture of hydrogen peroxide/chlorhexidine can be used. The bubbling action of the hydrogen peroxide helps remove debris. A Waterpik® is a very useful tool to help remove debris from the wires. If a Waterpik is used, care should be taken not to direct the jet stream directly over intraoral incisions as this may lead to wound dehiscence.

3. Physiotherapy
Physiotherapy can be prescribed at the first visit and opening and excursive exercises begun as soon as possible. Goals should be set, and, typically, 40 mm of maximum interincisal jaw opening should be attained by 4 weeks postoperatively. If the patient cannot fully open his mouth, additional passive physical therapy may be required such as Therabite or tongue-blade training.

v1.0 2008-12-01