Dissecting aneurysm of the radiculomedullary artery originating from extracranial vertebral artery dissection in a patient with rheumatoid cervical spine disease: an unusual cause of subarachnoid hemorrhage. Case report.

The authors report the case of a 65-year-old woman with atlantoaxial subluxation caused by rheumatoid arthritis. The patient had been hospitalized because of an infection after a total-knee replacement, when she suddenly lost consciousness and became apneic after an episode of intractable neck pain. Cranial computed tomography scanning demonstrated subarachnoid hemorrhage (SAH), and angiography revealed a dissecting aneurysm of the radiculomedullary artery that had originated from an extracranial vertebral artery dissection at the level of the atlantoaxial joint. Although coil embolization for the parent artery, including the dissecting aneurysm, was performed successfully, the patient died of worsening infection. The authors believe that the SAH occurred because of a ruptured dissecting aneurysm in the intradural portion of the radiculomedullary artery.