Treatment of Unclippable Giant Posterior Cerebral Artery Aneurysms with Detachable Balloons —Report of the Three Cases—

Three patients presented with rare giant posterior cerebral artery aneurysms, clinically manifesting as cerebral ischemia, mass effect, and subarachnoid hemorrhage. All aneurysms were partially throm bosed, originated at the P₂segment, and possessed broad necks. Surgical neck clipping was difficult but proximal occlusion of the parent artery was feasible. Aneurysm occlusion sparing the parent artery was attempted in all cases, but failed because the detachable balloon did not successfully block the aneurysmal neck. All patients tolerated test occlusion at the P₂ segment, so the parent ar tery was occluded proximally with detachable balloons, leaving the important perforating arteries unaffected. Twotransient ischemic attacks were associated with the procedure. Where surgical treat ment is unusually difficult, and proximal ligation or trapping just feasible, embolization with detach able balloons is an acceptable substitute.