Incidence of Fish-mouthing and Wall Malapposition of Different Flow Diverters in the Treatment of Cerebral Aneurysms: Device-specific Findings in a Retrospective Single-center Analysis

PURPOSE: Flow diverter (FD) braid stability is crucial for optimal wall apposition, thereby reducing the risk of device-related complications following intracranial aneurysm treatment. We compared wall apposition characteristics across different FD designs to evaluate inter-device differences. METHODS: Retrospective single-center analysis of 104 patients with 127 aneurysms treated with 121 FD (35 Derivo Embolization Devices (DED; Acandis, Pforzheim, Germany), 50 p64 (Phenox Wallaby, Bochum, Germany), 24 p48 (Phenox), 11 Silk (Balt, Montmorency, France), and 1 Pipeline (Medtronic, Dublin, Ireland)) between February 2013 and June 2023. The analysis focused on fish-mouthing-like deformities (≥ 10% focal diameter reduction at device ends) and the need for mechanical wall apposition maneuvers, as well as aneurysm occlusion, thrombus-associated events, and neurological outcomes. RESULTS: Fish-mouthing-like deformities occurred more frequently with DED (50.0%) than with other FD-types (27.2%; p = 0.021), mainly due to "pre"-fish-mouthing (31.3% vs. 14.8%; p = 0.047). Mechanical wall apposition maneuvers were more often required in DED cases (60.0% vs. 25.6%; p < 0.001), particularly for proximal malapposition. Aneurysm occlusion rates were comparable at final FU (84.2% vs. 88.6%; p = 0.563). Thrombus-associated events occurred more frequently with DED (29.4% vs. 11.3%; p = 0.008), though neurological outcomes did not differ significantly (6.0% vs. 2.6%; p = 0.148). Mean FU time was 26.0 ± 21.0 months. CONCLUSION: DED required more frequent intraprocedural wall apposition maneuvers and showed higher rates of fish-mouthing-like deformities compared with other FD-types. However, long-term aneurysm occlusion and neurological outcomes were comparable. These findings suggest that while DED deployment may require greater technical expertise, its safety and efficacy should be further evaluated in larger, multicenter studies.