Radiology in survivors of traumatic atlanto-occipital dislocation.

Traumatic atlanto-occipital dislocation is fatal, but survivals are reported. Six cases of survival after atlanto-occipital dislocation are presented. Lateral cervical spine radiographs demonstrated retropharyngeal swelling in all patients, and Powers' ratio was abnormal in five of six patients. Reformatted computed tomography (CT) images or three-dimensional CT were useful in confirming the diagnosis. Initial treatment consisted of immobilization with halo or collar, and, in one patient, Crutchfield tongs. Reduction of the dislocation was associated with decreasing Powers' ratio in five long-term survivors. Residual neurologic deficits, however, were seen in these patients. Atlanto-occipital dislocation should be suspected in trauma patients with findings of brain stem injury--especially agonal respirations, irregular heart rate, lower cranial nerve abnormality, and asymmetrical motor deficits.