Ruptured intracranial aneurysm associated with spontaneous occlusion of internal carotid artery. Experience with 5 cases.

Out of 921 patients diagnosed and treated for intracranial aneurysm in 5 cases (0.5%) the co-existence of ruptured aneurysm and occlusion of the internal carotid artery was found. 4 patients were treated surgically--aneurysm clipping--without serious post-operative complications and 6 months follow-up showed satisfactory results. In 4 of 5 cases the aneurysm was located on the anterior communicating artery (ACA); this fact may support the hypothesis concerning a possible role of enhanced blood flow in aneurysm formation and rupture. In cases with good collateral blood flow extra-/intracranial bypass before aneurysm occlusion seems not to be necessary. The risk of operation in those patients is not as high, as might be expected.