Supergiant anterior circulation aneurysms.

Six cases of very large anterior circulation intracranial aneurysms are presented. Aneurysms of 53-84 mm in three female and two male adults and a 40 mm lesion in a seven week infant were successfully excised. Three patients tolerated trial intraluminal balloon occlusion preoperatively and underwent subsequent parent artery ligation and aneurysmectomy with gratifying outcome. Three patients failed to tolerate trial occlusion and underwent prophylactic saphenous vein bypass grafts from the common carotid artery to the middle cerebral (MCA) prior to aneurysmectomy. In two of these (a 72 mm MCA and a 84 mm petrous carotid aneurysm), severe brain swelling after successful bypass procedures necessitated emergency craniotomy for aneurysmectomy and decompression. One of these never recovered and died one month later. In both cases in which malignant brain swelling followed bypass, preoperative CT and MR revealed significant hemispheric oedema and shift. Both patients had presented with signs of increased intracranial pressure and global mentational difficulties. Supergiant intracranial aneurysms pose major therapeutic risks, alternative therapeutic avenues must be addressed.