Cooperative study of ruptured vertebrobasilar artery aneurysms in the Tohoku district in Japan

A multicenter study investigated the clinical characteristics and overall outcome of 342 cases of ruptured vertebrobasilar artery aneurysms among 6783 ruptured intracranial berry aneurysms in 73 hospitals across the Tohoku district in Japan between 1992 and 1996. The incidence of ruptured vertebrobasilar artery aneurysms was less frequent than previously reported. The incidence was 5% among all intracranial berry aneurysms. One hundred eleven patients had aneurysms of the basilar artery bifurcation, 98 had vertebral-posterior inferior cerebellar artery aneurysms, 44 had basilar-superior cerebellar artery aneurysms, and 28 had distal posterior inferior cerebellar artery aneurysms. Aneurysm clipping was performed in 238 cases (70%), intravascular treatment in 22 (6%), drainage in 22 (6%), and conservative treatment in 60 (18%). Approximately 50% of patients were in good condition at admission. At 3-month follow up, 46% had good recovery, 14% had moderate disability, 10% had severe disability, 4% were vegetative state, and 27% died. Vertebral artery aneurysms showed favorable outcomes compared to basilar artery bifurcation aneurysms. Surgical results in the 238 operated cases were good recovery in 60%, moderate disability in 18%, severe disability in 10%, vegetative state in 2%, and death in 11% of cases. Worse postoperative outcomes were observed in patients with high preoperative Hunt and Kosnik grades or aneurysms larger than 10 mm, and in patients over 70 years of age.