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 fol-low-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 record-ing (intra-procedural, peri-procedural and delayed) complications in order to deter-mine 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 imag-ing 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 aneur-ysms 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 aneu-rysm 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.