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

Abstract Objective Middle cerebral artery aneurysms (MCAas) with rupture and unruptured IAs are considered good candidates for microsurgery. The objective of the present study was to evaluate the risk of complications and the risk factors for microsurgical treatment of MCAas to better define the indications for microsurgery. Methods We conducted a retrospective cohort study based on data provided from three French tertiary neurosurgical units from January 1, 2013 to May 31, 2020. We first collected data on all the patients who required microsurgical treatment for MCAas. We evaluated the frequency of complications and finally 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 (re)bleeding of the treated aneurysm and symptomatic surgical site hematoma. We then compared patients with and without complications using univariate and multivariate analyses. Results Between January 2013 and May 2020, 292 MCAas in 284 patients were treated. A total of 29 (9.9%) MCAas had a complication. The complications were as follows: symptomatic cerebral ischemia: 4.8%, aneurysm rebleeding: 0.3%, surgical site hematoma: 1.0%, impossible exclusion: 0.3%, and incomplete exclusion: 4.1%. However, severe complications, defined as death or a modified Rankin score (mRs) score ≥4 at 3 months, were infrequent and occurred in 7/292 patients (2.4%). In the multivariate analysis, independent risk factors for complications were the following: a ruptured aneurysm, a larger maximum IA size, a larger neck size, and arterial branches passing less than <1 mm from the IA neck or dome. Conclusions MCAa surgery is a safe procedure with a low rate of serious procedure-related complications and an excellent rate of occlusion. The risk factors for complications are a ruptured aneurysm, a larger IA, a larger neck size, and the presence of an “en passage” arterial branch less than 1 mm from the IA. In these cases, at least for factors that do not present a significant difficulty for EVT, such as the presence of an “en passage” artery or ruptured IA, EVT has to be more thoroughly discussed.