Odontoid Fractures: Evaluation and Management.

Fractures of the odontoid process are uncommon injuries. Fracture displacement, compromised blood supply, comminution, and iatrogenic distraction have all been implicated in the reported high rates of nonunion. Plain radiography, polytomography, and computed tomography are all useful in delineating the fracture pattern. Magnetic resonance imaging has been recommended for evaluating associated ligamentous injuries and may be helpful in detecting occult cervical spine fractures. Type I fractures are avulsion fractures of the tip of the odontoid process. These rare injuries require only external immobilization with an orthosis if there is no associated ligamentous injury. Type II fractures occur at the junction of the odontoid process and the body of the axis. These are the most common odontoid fractures and are associated with a high incidence of nonunion. Nondisplaced fractures should be treated with halo immobilization for 8 to 12 weeks, with careful clinical and radiographic monitoring. Displaced fractures should be considered for operative treatment, either with atlantoaxial arthrodesis or anterior screw fixation. Type III fractures, which extend into the body of the axis through cancellous bone, are treated with closed reduction and halo immobilization.