Surgical Treatment of Giant Basilar Tip Aneurysms with Unilateral Internal Carotid Artery Occlusion

Abstract

We report 4 cases of giant aneurysms in the basilar tip region, comprising 1 large and 3 giant aneurysms located in the basilar tip (2 cases), basilar-SCA (1 case), and PCA (1 case). One of the 4 was ruptured (basilar tip aneurysm). The symptoms were headache (3 cases) and oculomotor palsy (1 case; basilar-SCA). All aneurysms had unilateral internal carotid artery occlusion. In all cases the aneurysms were clipped following EC-RA-M2 bypass to prevent ischemia at the area of the occluded internal carotid artery and to reduce hemodynamic stress within the aneurysm. The clinical courses of 2 basilar tip aneurysms were good but 1 basilar-SCA aneurysm re-grew and ruptured 4 years later after incomplete clipping of the aneurysm. In 1 PCA aneurysm a new basilar tip aneurysm occurred that grew progressively. We consider that the cause of these aneurysms was hemodynamic stress due to internal carotid artery occlusion. It is suggested that the internal carotid artery should not be occluded without an EC-RA-M2 bypass.