Impact of WEB Device Height Sizing on Outcomes in Intracranial Aneurysm Treatment

Introduction: The Woven EndoBridge (WEB) system is used to treat wide-necked intracranial bifurcation aneurysms. Long-term occlusion depends on appropriately oversizing the WEB relative to aneurysm width. The impact of WEB height relative to aneurysm height has not been studied, but adequate flow disruption near the neck may suffice for closure. Using a shorter WEB device is often easier to deploy, likely safer, and could reduce the current portfolio of 37 device sizes for aneurysms between 3 and 10 mm wide.

Methods: To evaluate the impact of WEB height sizing on outcomes, we retrospectively analyzed the World-Wide-Web registry. Final WEB height was estimated by adding the difference between the WEB and aneurysm widths to the WEB height, accounting for elongation due to radial forces. Patients were categorized into two groups: complete fill (WEB height within 2 mm of aneurysm height) and partial fill (WEB height at least 2 mm shorter than aneurysm height, indicating residual dome NOT filled). Univariate and multivariate analyses assessed outcome measures.

Results: Of 443 patients, 293 treated with an appropriately oversized WEB device (width at least 0.5 mm larger than aneurysm width) were included. Mean age was 60.3 years; 24% male; 57% smokers; 62% anterior circulation aneurysms; 22% ruptured; mean aneurysm height 6.37 mm; width 5.46 mm. No differences between partial and complete fill groups were observed in fluoroscopy time (36.95, 30.66min, p=0.47), complications (8.7%, 8.4%, p=1.0), occlusion rates where 3 is complete, 2 partial and 1 inadequate (2.53, 2.48, p=0.51), or retreatment (10.5%, 7.6%, p=0.47). Multivariate analysis confirmed no significant differences.

Conclusion : No significant differences were observed in outcomes between groups. This suggests that if the WEB is appropriately oversized relative to width, undersizing the height does not result in poorer outcomes. This could allow for a reduced portfolio of device sizes, potentially improved safety profile, and may be applicable to other intra-saccular devices under investigation (e.g., Contour and Seal devices).