Treatment of Ruptured and Unruptured Intracranial Aneurysms with WEB 17 Versus WEB 21 Systems : Comparison of Indications and Early Angiographic Outcomes.

BACKGROUND The concept of intrasaccular flow diversion using the Woven EndoBridge (WEB) device changed the traditional endovascular concept for wide-necked bifurcation aneurysms. The latest technical advancement resulted in the WEB 17 system, a softer device composed of fewer wires which enables treatment of smaller more distally located aneurysms by using smaller microcatheters as compared to the WEB 21 system. OBJECTIVE This retrospective observational study aimed to evaluate and compare the angiographic and clinical results achieved with WEB 21 and WEB 17 in aneurysm morphologies eligible for both systems (maximum width 3-6 mm). METHODS Between August 2014 and August 2019 a total of 63 and 130 aneurysms with a maximum width of 3-6 mm were treated with either WEB 21 and WEB 17, respectively, at 2 neurovascular centers. Cases were analyzed based on a comparison regarding aneurysm size, location and rupture status. RESULTS The technical success, the periprocedural complication rate and the rate of additional devices used showed no relevant differences between the two groups. Aneurysms treated with the WEB 17 system were smaller and more frequently distally located. The overall complete occlusion rate at 3 months was higher in the WEB 17 group (65.5% versus 55.1%). The superiority of complete aneurysm occlusion achieved with WEB 17 was statistically significant in the subgroup of unruptured middle cerebral artery aneurysms. CONCLUSION The use of WEB 17 expands the treatment indications for intrasaccular flow-diversion towards smaller and more distally located aneurysms with a safety profile comparable with that of the WEB 21.