Isolated posterior spinal artery aneurysm causing intracranial acute subarachnoidal hemorrhage.

A case of an isolated posterior spinal artery aneurysm of the upper cervical spinal cord is presented. Spinal artery aneurysms that are not associated with other entities are extremely rare. Four cases have been reported in the literature to date. The patient developed symptoms and signs of intracranial subarachnoid hemorrhage. The aneurysm was successfully clipped. No other vascular abnormalities were seen.