Various techniques of stent-assisted coil embolization of wide-necked or fusiform artherosclerotic and dissecting unruptured vertebrobasilar artery aneurysms for reducing recanalization: mid-term results

Background Coil embolization of wide-necked or fusiform vertebrobasilar aneurysms is challenging and tends to involve frequent recanalization. Purpose The aim of our study was to evaluate complications and mid-term outcomes of complex vertebrobasilar artery aneurysms after stent-assisted coiling with various techniques. Methods We retrospectively evaluated 28 cases of unruptured vertebrobasilar aneurysm treated by stent-assisted coiling. Results Forty-four of the 45 stents placed in 28 patients were deployed at the desired location (97.8 %). Single stent-assisted coiling was performed in 14 aneurysms, a stent-within-a-stent (SWS) technique was used in 12 aneurysms, and Y-stent-assisted coiling was employed in four basilar tip aneurysms. Two basilar tip aneurysms treated by single stent-assisted coiling recurred and were retreated by SWS and Y-stent-assisted coiling. Complete embolization was achieved in 19 aneurysms (67.8 %), and remnant neck persisted in eight aneurysms (28.6 %) and remnant aneurysm was noted in one aneurysm (3.6 %). Permanent neurologic deficit (Modified Rankin Scale 1 and 4) was noted in two patients (7.1 %). Angiographic follow-up (mean follow-up period: 20.8 months) was performed in 20 patients. Major recanalization occurred in two basilar tip aneurysms (10 %) and minor compaction was noted in one superior cerebellar artery aneurysm. The remaining 17 aneurysms were stable or improved (85 %). Conclusions Complex vertebrobasilar aneurysm embolization with stent-assisted techniques was effective and feasible as a method for reducing recanalization during midterm angiographic follow-up. Large and wide-necked basilar tip aneurysms showed frequent major recanalization, and compact packing with single or Y-stent-assisted coiling is needed to prevent recanalization even if coiling will be done without stenting.