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Neuroradiology Case of the Week

Case 287

Ashwani K. Sharma, MD and P-L Westesson, MD, PhD, DDS

Clinical Presentation: Patient is a 28-year-old male who presented with pain with distortion of the jaw following assault.

Imaging Findings: Plain radiographs can help define the fractures of the mandible. In a patient with an isolated jaw injury, a panorex is the ideal radiograph to visualize the fracture and condition of the teeth. In the multisystem injured patient a computerized tomographic scan with three dimensional reconstruction provides good visualization of the fractures.

Diagnosis: Mandibular fractures

Discussion: Fractures of the mandibular body may be classified by anatomic location, condition, and position of teeth relative to the fracture, favorableness, or type. Fractures can be open, that is, exposed to air inside the mouth or outside the facial skin or closed, that is, completely covered by soft tissue . Fractures can further be characterized as complete (the bone is broken completely into two or more pieces) or incomplete (the bone behaves like a green stick, fracturing only partway through and bending on the opposite side). Finally if the fracture is composed of many pieces it is termed "comminuted". Mandible fractures are also described by the relationship between the direction of the fracture line and the effect of muscle distraction on fracture fragments. Mandible fractures are favorable when muscles tend to draw bony fragments together and unfavorable when bony fragments are displaced by muscle forces. Vertically unfavorable fractures allow distraction of fracture segments in a horizontal direction. These fractures tend to occur in the body or symphysis-parasymphysis area. Horizontally unfavorable fractures allow displacement of segments in the vertical plane. Angle fractures are often unfavorable because of the actions of the masseter, temporalis, and medial pterygoid muscles, which distract the proximal segment superomedially.

Frequency: In general, incidences of fractures of the mandibular body, condyle, and angle are relatively similar, while fractures of the ramus and coronoid process are rare. The literature suggests the following mean frequency percentages based on location:

• Body - 29%
• Condyle - 26%
• Angle - 25%
• Symphysis - 17%
• Ramus - 4%
• Coronoid process - 1%

Etiology: Vehicular accidents and assaults are the primary causes of mandibular fractures throughout the world. Data from industrialized nations suggest that mandible fractures have various causes as follows:

• Vehicular accidents - 43%
• Assaults - 34%
• Work-related causes - 7%
• Falls - 7%
• Sporting accidents - 4%
• Miscellaneous causes - 5%
  

Assault most often causes mandible angle fractures.

Treatment: Reduction and stabilization of the mandible fracture is the key to successful treatment. The method of management may vary based on the severity, location of the fracture and presence or absence of teeth. Mandible fractures are usually treated by closed reduction with wiring of the teeth or open reduction with internal rigid fixation using plates

References:

1. Al-Assaf DA, Maki MH. Multiple and comminuted mandibular fractures: treatment outlines in adverse medical conditions in Iraq. J Craniofac Surg. 2007 May;18(3):606-12. [Medline]
2. Subhashraj K, Nandakumar N, Ravindran C. Review of maxillofacial injuries in Chennai, India: A study of 2748 cases. Br J Oral Maxillofac Surg. 2007 May 22. [Medline]