Angiographic features, surgical management and outcomes of proximal middle cerebral artery aneurysms

Objective: Understanding the microanatomy of the proximal middle cerebral artery (M1) and its early branches is very important for aneurysm surgery in this region. However, few articles provide detailed descriptions of such aneurysms. We report the angiographic characteristics of a series of M1 aneurysms and our experience with M1 aneurysm surgery. Materials and methods: Twenty-three patients with 25 (combined) M1 aneurysms presented to our institution from January 2001 to December 2006. We examined the general characteristics and angiographic features of the M1 aneurysms, such as site, size, direction, and their association with early branches. Results: Of the 23 patients with M1 aneurysms, 13 were women and 10 were men. Nineteen of the aneurysms had ruptured prior to presentation. Multiple aneurysms were observed in 10 of the patients. Angiography showed that 14 of the aneurysms were less than 5 mm in size, and most of the aneurysmal projections were superior. Eighteen of the aneurysms involved early frontal branches and three involved the lenticulostriate arteries. Postoperative infarction was seen in eight patients. Five of the eight patients showed either no or slight neurological deficits at the follow-up visit. One patient, however, suffered from hemiparesis and aphasia that corresponded to the vascular territory of the early frontal branches and lenticulostriate arteries. Two patients had a total MCA infarction and a posterior fossa infarction, respectively. Conclusions: This study highlights the need for the critical management of M1 aneurysms, taking into consideration the size and number of aneurysms. By performing careful angiographic investigation of the aneurysm and related early arterial branches of M1, postoperative complications may be minimized.