Vasospasm of the Vertebrobasilar System in Cases of Ruptured Intracranial Aneurysm

The reported incidence of vasospasm in cases of ruptured vertebrobasilar (VB) aneurysm varies considerably. The classification into local and diffuse spasm may partially explain the discrepancy. In the present small series, we found that local spasm is more common than diffuse spasm, which is rare in cases of ruptured VB aneurysm when compared with ruptured supratentorial aneurysm. It is hoped that further work may help to explain this apparent difference between the anterior and the posterior circulation and may contribute to the understanding of vasospasm.