Flow diverter devices in the treatment of complex middle cerebral artery aneurysms when surgical and endovascular treatments are challenging

Objective: In this study, the authors retrospectively evaluated the effectiveness and the safety of non-surgical middle cerebral artery (MCA) aneurysms treated via the implantation of a flow diverter device (FDD). Methods: Clinical, procedural and follow-up data were analyzed in order to evaluate the safety and effectiveness of the treatment with the FDD in complex MCA aneurysms. Safety was assessed recording (intra-procedural, peri-procedural and delayed) complications in order to determine the morbidity and mortality rates. Functional outcome was evaluated with modified Rankin Scale (mRS) prior and after the endovascular procedure. To assess the efficacy, midterm and long-term clinical, angiographic and cross-sectional imaging follow-ups were recorded. Results: 47 patients (21 males; 26 females) with MCA aneurysms were treated with FDD. 7 were ruptured. 21 aneurysms were saccular, 19 dissecting, 3 fusiform, 2 blood blister-like and 2 were pseudo-aneurysms. 14 aneurysms were small, 23 large and 10 giant, with a mean size of 15.3 mm. 8 aneurysms were recurrent (Raymond-Roy class III): 2 patients had an aneurysmal sac recanalization after being treated with simple coiling and 6 after being treated with microsurgical clipping. In 4 cases (8.5%), more than one FDD was telescopically positioned in order to treat the aneurysm, for a total of 54 FDDs used. The overall mortality rate was 2.1% (1/47) and the overall morbidity rate was 8.6% (4/47). Midterm neuroimaging follow-ups showed the complete occlusion of the aneurysm in 63% cases, which became 91% at the end of the follow-up. Conclusions: FDD is a safe and effective tool that can be used in the treatment of complex MCA aneurysms, where conventional neurosurgical treatments can be challenging or ineffective.