Background: The objective was to assess the surgical results in complex middle cerebral artery (MCA) aneurysms.
Methods: 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.
Findings: 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.
Conclusions: 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.