Endovascular and Microsurgical Treatment for Middle Cerebral Artery Bifurcation Aneurysms: Experience From 10 High-Volume United States Cerebrovascular Centers

BACKGROUND AND OBJECTIVES: Middle cerebral artery bifurcation (MCAb) aneurysms have primarily been managed through microsurgical clipping (MC). However, the effectiveness and safety of evolving neurointerventional methods warrant a comprehensive examination and comparison with MC. We investigated patient and MCAb aneurysm characteristics and compared imaging outcomes for MC, simple coiling (SC), stent-assisted coiling (SAC), flow-diverting stent placement (FD), and endosaccular flow disruption. METHODS: A retrospective review of MCAb aneurysm databases from 10 US centers was conducted to identify patients treated between January 2008 and January 2023. Primary analyses compared data across all 5 treatment modalities individually and for MC vs endovascular modalities. Secondary analyses consisted of pairwise comparisons between these modalities for saccular MCAb aneurysms. RESULTS: We analyzed data for 1060 patients with 1060 MCAb aneurysms (MC = 722, SC = 134, SAC = 106, FD = 34, and endosaccular flow disruption = 64). The treatment groups differed significantly in mean patient age (P < .001), sex distribution (P = .044), and baseline mRS score (P < .001). No treatment preference was noted for recurrent aneurysms. Ruptured aneurysms were most common in SC and least common in FD (P < .001). Wide-necked aneurysms were most frequent in FD (P < .001). Intraoperative complications were similar, although SAC had more vasospasm (P = .006) and device-related complications (P = .010), and FD had more thromboembolic events (P = .047). Postoperative complications varied (P = .007): MC had more vasospasm (P = .043). Follow-up durations varied significantly (P < .001). Follow-up complications differed (P = .012): FD had more transient ischemic attacks (P = .042) and ischemic strokes (P < .001); SC had more aneurysmal rehemorrhage (P = .027). Immediate and final aneurysmal occlusion was considerably better with MC (P < .001), followed closely by SAC. CONCLUSION: MC remained the preferred modality for treating both unruptured and ruptured MCAb aneurysms, demonstrating superior immediate and final angiographic occlusion rates with minimal intraoperative and postoperative complications. SAC showed similar safety but was technically more challenging, FD had higher ischemic event rates, and SC had more delayed reruptures.