Microsurgical clipping of middle cerebral artery aneurysms: complications and risk factors for complications

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.

Feasibility and safety of partial resection of the anterior insular cortex for microsurgical treatment of middle cerebral artery aneurysms located in the limen recess: patient series

BACKGROUND When performing clip ligation of superior projecting aneurysms of the proximal (M1) segment of the middle cerebral artery (MCA), meticulous sylvian fissure dissection alone may be inadequate for safe clip application, especially in cases in which the aneurysm is buried in the limen recess, since the limen insulae may be positioned lateral to the aneurysm. In the present patient series, the authors present their surgical technique for clip ligation of aneurysms located in the limen recess, with partial resection of the limen insulae. OBSERVATIONS A retrospective analysis of patients who had undergone clip ligation of MCA aneurysms located at the limen recess at a single institute was performed. Patients with angiographic and clinical follow-up data were considered eligible. A total of 11 aneurysms (4 ruptured and 7 unruptured aneurysms) in 11 patients were evaluated. Postoperative ischemic lesions were observed on images obtained within 1 week after surgery in 5 (45.5%) patients who had undergone partial resection of the limen insulae, although none of them presented with neurological deterioration. LESSONS Partial resection of limen insulae may be feasible to avoid severe ischemic complications following clip ligation of M1 aneurysms embedded in the limen recess.

Pipeline embolization of proximal middle cerebral artery aneurysms: A multicenter cohort study

Background and purpose Flow diversion of aneurysms located in the M1 segment and middle cerebral artery bifurcation with Pipeline embolization device is sometimes performed, but further study is needed to support its regular use in aneurysm treatment. Here, we report measures of safety and efficacy for Pipeline embolization in the proximal middle cerebral artery in a multi-center cohort. Materials and methods Clinical and angiographic data of eligible patients were retrospectively obtained from participating centers and assessed for key clinical and angiographic outcomes. Additional details were extracted for patients with complications. Results In our multi-center cohort, complete aneurysm occlusion was achieved in 71% (17/24) of treated aneurysms. There were no deaths or disabling strokes, but non-disabling ischemic strokes occurred in 8% (2/24) of patients. For aneurysms in the M1 segment, complete aneurysm occlusion was observed in 75% (12/16) of aneurysms, aneurysm volume reduction was observed in 100% (16/16) of aneurysms, and non-disabling ischemic strokes occurred in 13% (2/16) of patients. For aneurysms at the middle cerebral artery bifurcation, complete aneurysm occlusion was observed in 63% (5/8) of aneurysms, aneurysm volume reduction occurred in 88% (7/8) of aneurysms, and ischemic or hemorrhagic complications occurred in 0% (0/8) of patients. Conclusion Pipeline embolization of cerebral aneurysms in the M1 segment and middle cerebral artery bifurcation demonstrated a 71% rate of complete aneurysm occlusion. There were no deaths or disabling strokes, but there was an 8% rate of non-disabling ischemic strokes.