DEVELOPMENT OF A DISSECTING ANEURYSM ON THE VERTEBRAL ARTERY IMMEDIATELY AFTER OCCLUSION OF THE CONTRALATERAL VERTEBRAL ARTERY - A CASE-REPORT

A 49 year old female presented with subarachnoid hemorrhage due to a r uptured dissecting aneurysm on the left vertebral artery (VA). Followi ng an occlusion test, we per formed proximal occlusion of the left VA with detachable balloons. However, a dissecting aneurysm on the right VA developed three weeks later. After an occlusion test had showed no change in cerebral blood flow auditory brain stem response, or neurolo gical status, proximal occlusion of the right VA was performed. The pa tient has returned to normal life without neurological deficits. Bilat eral dissecting aneurysms of the VA are quite common, but de novo VA d issecting aneurysms or enlargement of such aneurysms after occlusion o f contralateral VA are rare. This case suggests that hemodynamic stres s may be a causal factor in the development of VA dissecting aneurysms . Careful pre- and post-operative neuroradiological examination of the contralateral VA are required in patients undergoing VA occlusion for dissecting aneurysms.