Laboratory Studies
No lab studies are needed to evaluate these fractures; however, they may be indicated in the evaluation of associated injuries.
Imaging Studies
See the list below:
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Computed tomography (CT) scans have become the criterion standard for evaluating the mandible for fractures.
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In patients with multiple traumas, many emergency departments obtain near whole-body CT scans, which may provide useful information.
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The panoramic dental radiograph is an excellent tool for imaging the traumatized mandible. When the needed equipment is not available or the patient cannot be placed in the apparatus, plain radiographs of the mandible may be sufficient.
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Three-dimensional reconstructions of CT scans can be useful to evaluate complex mandibular fractures. The ultimate imaging tool is the stereolithographic model, which some centers are able to make from CT scan images. These are life-size models of the facial bones made of a plastic resin that can be handheld. They can be useful in planning treatment and may be used as templates for contouring rigid hardware or constructing splints and other adjunctive appliances.
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Evaluation of the entire mandible is important because multiple fractures are common. If the blow was directed at the anterior arch of the mandible, excluding fractures of the subcondylar areas is mandatory.
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The broad red line indicates the symphyseal area. The pink area between the cuspid teeth, excepting the symphysis, indicates the parasymphyseal area.
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The model on the left shows comminuted fractures. The model on the right has been repaired to facilitate preoperative contouring of a reconstruction plate.
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Opposing lag screws have been used to treat a symphyseal fracture. This procedure requires precise technique and is not for the occasional operator.
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Two miniplates are required for the symphysis/parasymphysis region because it is subjected to torsional forces, which would be poorly resisted by one miniplate.
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Tension banding is required to prevent splaying of the fracture line at the superior surface of the mandible when using a dynamic compression plate. A mandibular arch bar can accomplish this. In this example, a miniplate is used.
