Treatment of middle cerebral artery aneurysms with flow diverter stents: A single-center experience

Objective: This thesis aims to evaluate the single-center experience of treating middle cerebral artery (MCA) aneurysms using flow diverter (FD) stents. Due to the bifurcation anatomy, perforator-rich segments, and frequent wide-neck morphology, FD application in the MCA is technically demanding. The study focuses on assessing the feasibility, safety, and angiographic outcomes of FD treatment in this vascular territory. Scope: A total of 59 patients treated with FD between 2013 and 2025 were included. Demographic characteristics, aneurysm morphology, treatment strategies, device specifications, and angiographic follow-up results were comprehensively analyzed. Methods: Data were retrospectively collected from patient files and the PACS archive. Aneurysm characteristics (segment, size, morphology, rupture status), stent type/diameter/length, branch coverage, periprocedural complications, and follow-up angiographic evaluations using the Modified Cekirge–Saatci Classification were recorded. Post-procedural stagnation patterns were assessed using the 4A–4B system and analyzed for their association with aneurysm occlusion. Results: The mean age of the patients was 57.6 years, and the majority of the aneurysms were minor and unruptured. The predominant location of aneurysms was the M1 segment (69.5%), and they exhibited a wide-necked morphology (91.5%). Pipeline Shield was the predominant FD device, utilized by 40% of users. The periprocedural complication rate was documented at 28.8% (n=17), although the overall mortality rate was 1.7% (n=1). Functional independence (mRS 0–2) was maintained in 14 of 15 patients (93.3%) who experienced problems and were monitored long-term, with mortality occurring in only one patient (6.7%) due to acute cerebral hemorrhage. No significant neurological abnormalities were observed in this cohort of live patients; nevertheless, modest neurological symptoms persisted in two individuals (13.3%), and total radiological blockage was accomplished in 60.0% of cases. During the initial control period, the total stent patency was 97.8%, whereas the branch patency was 62.2%. In patients assessed during the final follow-up, stent patency was 82.6%, while branch patency was 62.2%. No statistically significant correlation was identified between the stagnation pattern and the eventual occlusion. Conclusion: This study illustrates that flow-diverting stents represent a feasible and secure therapeutic alternative for MCA aneurysms in some instances. Despite elevated rates of neurological complications in the early postoperative phase, long-term assessments indicate that this procedure does not result in lasting morbidity, and functional independence is preserved. In the majority of patients, the continuity of flow in the parent vessel and side branches was maintained, and it was seen that occlusive processes progressed gradually over time. The restricted patient sample and absence of long-term follow-up constrain the generalizability of the findings. Further prospective trials with bigger patient cohorts are required. Keywords: Flow Diverter Stent, Aneurysm Occlusion, Modified Cekirge–Saatci Classification, Endovascular Treatment, MCA Aneurysm, Branch Patency.