穿通枝梗塞で発症した右中大脳動脈M1部紡錘状動脈瘤の治療  [in Japanese] Treatment of a Fusiform Middle Cerebral Artery Aneurysm at M1 Part Which Cause Cerebral Infarction at Its Perforating Area : A Case Report  [in Japanese]

We report the case of a fusiform middle cerebral artery aneurysm at the M1 segment, which was successfully treated with proximal occlusion after a bypass surgery. A 48-year-old-male was admitted with a chief complaint of repeated left hemiparesis. Cerebral angiography showed a fusiform aneurysm at the M1 segment on the right side, corresponding to the ischemic symptom. We performed the occlusion of M1 at its most proximal segment after the high flow bypass from external carotid artery to M2 with a radial artery graft. The post-operative course was uneventful, and the patient was discharged 10 days after operation. Follow-up imaging studies showed the prominent thrombus formation inside the aneurysm keeping the blood flow from the aneurysmal wall to the M1 perforators intact. This surgical result supports the hypothesis that the spontaneous fusiform MCA aneurysm might be caused by dissection and the reversing of blood flow inside the dissected artery might make the dissection subside.