Microsurgical Clipping of Middle Cerebral Artery Aneurysms: Complications and Risk Factors for Complications

Middle cerebral artery aneurysms (MCAAs) have been considered good candidates for microsurgery. Our objective was to evaluate the risk of complications and the risk factors for complications with microsurgical treatment of MCAAs to better define the indications for microsurgery. We conducted a retrospective cohort study from 3 tertiary neurosurgical units from January 2013 to May 2020. We evaluated the frequency of complications and searched for the risk factors for complications after microsurgery. Complications were defined as a composite criterion with the presence of one of the following: procedural-related death, symptomatic cerebral ischemia, impossible exclusion, incomplete exclusion, or rebleeding of the treated aneurysm and symptomatic surgical site hematoma. A total of 292 MCAAs were treated, with 29 complications (9.9%), including symptomatic cerebral ischemia (4.8%), aneurysm rebleeding (0.3%), surgical site hematoma (1.0%), impossible exclusion (0.3%), and incomplete exclusion (4.1%). Severe complications, defined as death or a modified Rankin scale score of ≥4 at 3 months, were infrequent, occurring in 7 of the 292 patients (2.4%). On multivariate analysis, the risk factors were a ruptured aneurysm, a larger maximum aneurysm size, a larger neck size, and arterial branches passing <1 mm from the aneurysm neck or dome. Microsurgical management of MCAAs can be performed with very low morbidity rates. In some cases, at least for factors that do not result in significant difficulty for endovascular therapy, such as the presence of an en passage artery or ruptured aneurysm, endovascular therapy can be considered to be as safe and effective as clipping.