Carotid and vertebral artery injury in survivors of atlanto-occipital dislocation: case reports and literature review.

Atlanto-occipital dislocation (AOD) usually results in immediate death from transection of the upper cervical spinal cord near the spinomedullary junction. However, over the last several decades increasing numbers of AOD survivors have been identified. Although many of these patients initially demonstrate profound neurologic deficits, a number who survive have regained most or all neurologic functions, indicating that they did not suffer mechanical disruption of the spinal cord at the time of AOD. In the survivors, a growing body of evidence indicates that many of the initial neurologic deficits are related to vascular injury to the carotid or vertebral arteries and their branches. We recently encountered three AOD survivors with no evidence of mechanical injury to the spinal cord in which angiography demonstrated vascular injury to the internal carotid artery in the form of vasospasm in one case and to the vertebral arteries in the forms of focal stenosis at the site of dural penetration, focal stenosis and distal vasospasm, and focal stenosis with distal intimal flap and dissection in one case each. Autopsy after one of the three died after cardiac arrest demonstrated diffuse infarction of the cerebrum, cerebellum, midbrain, brainstem, and upper cervical spinal cord without evidence of mechanical laceration or transection of the spinal cord. Recovery of neurologic function in two cases following prompt immobilization and angiography suggests that neurologic deficits secondary to vascular injury are potentially reversible.