Occipito-atlantal dislocation: an uncommon case of cervical spine injury.

Occipito-atlantal dislocation (OAD) is a rare but often lethal type of spinal injury that can be found in up to 35% of traffic fatalities. Improved pre-hospital care, diagnosis, and immobilization of these patients have led to an increase in reported cases of survivors. Significant ligamentous disruption in OAD results in craniocervical instability. While the vast majority of patients will not survive, those who do present with a wide variety of neurological findings ranging from no deficit to quadriparesis with cranial nerve palsies. When the appropriate landmarks can be identified OAD can be identified on plain lateral cervical spine radiographs by using the basion-axial interval and basion-dental interval (or BAI-BDI) method. When this measurement is normal, but prevertebral soft tissue swelling is present, additional imaging such as magnetic resonance imaging and computerized tomography are useful to aid in making the diagnosis. Once this is established, immobilization followed by occipitocervical fusion is recommended. We present a case of a patient who survived for a brief period of time after being hit by a vehicle and who was found to have OAD. We discuss the pathophysiology, imaging, clinical findings, and treatment for this type of spinal injury.