Treatment results for complex middle cerebral artery aneurysms. A prospective single-center series

The objective was to assess the surgical results in complex middle cerebral artery (MCA) aneurysms.

From 1999 to 2009 the data of 330 patients with ruptured and unruptured MCA aneurysms were included into a prospective database. Degree of aneurysm occlusion and clinical outcomes were analysed after 271 surgical and 59 endovascular treatments assigned in an interdisciplinary approach. Aneurysms of large size and/or broad base, calcifications, and incorporation of M1 or M2 segments into the aneurysm base were defined as complex.

At least one of the criteria for complexity mentioned above was met in 97.8% of the MCA aneurysms that were treated surgically and in 76.3% that were treated endovascularly. In MCA aneurysms treated surgically, complete occlusion was achieved in 264 of the 271 (97.4%) aneurysms. Aneurysms with remnants after surgical treatment were significantly larger in size (17 ± 3 mm vs 7 ± 5 mm), and exhibited significantly more often parent vessel involvement (M1: 86% vs 27%; M2: 100% vs 67%) compared with the group of aneurysms that could be treated without remnant. Compared with our institutional data (52.5% complete occlusion rate) and data of the literature (up to 46.1% complete occlusion rate), the occlusion rates of endovascularly treated MCA aneurysms were significantly lower compared with MCA aneurysms treated surgically.

Surgical treatment of ruptured and unruptured MCA aneurysms results in a significantly higher rate of complete aneurysm occlusion compared with endovascular treatment, despite a high rate of complex aneuryms in the surgically treated group.