Flow alteration strategies for complex basilar apex aneurysms: multicenter experience, systematic review, and insights from computational fluid dynamics

Complex basilar apex aneurysms (CBAAs) present a significant challenge due to their unfavorable natural history and difficulty with conventional treatments. This study aimed to provide insights into flow alteration strategies by combining a systematic review using PRISMA methodology with a multicenter experience from South Korea. We analyzed 57 cases, finding that flow preservation with aneurysm obliteration was performed in 12.7%, while mild, moderate, and maximum flow reduction were applied in 77.2%, 7.0%, and 3.5% respectively. Outcomes showed that 75.8% of patients with available imaging achieved satisfactory aneurysm obliteration. A good clinical outcome (mRS 0–2) was observed in 49.1% of cases. However, poor outcomes (mRS 4–6) were reported in 31.6%, with a mortality rate of 17.5%. Beyond simply reducing intra-aneurysmal flow, computational fluid dynamics (CFD) simulations revealed that alterations in flow balance and direction significantly influenced hemodynamic stress. Given the severe prognosis of CBAAs, flow alteration strategies can serve as viable alternatives when conventional treatments are not feasible. Furthermore, CFD simulations might hold promise in identifying optimal strategies that can maximize aneurysm control while minimizing procedural risks.