Intracranial bypass grafts for vertebral-basilar ischemia.

Fourteen operations in which an occipital branch of the external carotid artery was anastomosed to the posterior inferior cerebellar artery were performed for occlusions or inaccessible stenotic lesions of the vertebral arteries proximal to the site of origin of the posterior inferior cerebellar artery. Eight patients (group 1) had no major focal reurologic deficit but were considered to be at high risk for a posterior circulation infarct; six patients (group 2) had been severely or moderately disabled before the operation. Postoperative angiography revealed that 13 of the 14 grafts were patent. In 9 of the 13 patent grafts, the bypass graft served as the sole or major blood supply of the vertebral-basilar system; in 4, flow was limited to the distribution of the posterior inferior cerebellar artery. Five of the eight patients in group 1 have returned to full employment or normal retired life. Two of the six patients in group 2 have resumed normal activities with only minimal neurologic dysfunction. This procedure may have a role in the management of highly selected patients suffering from vertebral-basilar ischemia, and it may be useful in the management of selected aneurysms in the vertebral-basilar system.