Background and purpose Multiple aneurysms have a high reported incidence, but the optimal treatment strategy is not clear. The aim of this study was to evaluate the safety and effectiveness of single-stage endovascular treatment of multiple aneurysms with a combination of various endovascular techniques.

Materials and methods Fifty-three consecutive patients with multiple intracranial aneurysms who underwent single-stage endovascular treatment for ≥2 aneurysms from June 2011 to May 2016 were included in the study. Patient and aneurysm characteristics, treatment technique, complications, clinical and angiographic outcomes were retrospectively evaluated.

Results 125 of 128 aneurysms (97.6%) were treated by the following endovascular techniques: simple coiling in 19, balloon-assisted coiling in 27, stent-assisted coiling in 33, flow diverters in 43, intrasaccular flow modifiers in 2, and a neck-bridging device in 1. Overall mortality and mortality directly related to the single-stage treatment was 15% (8/53) and 3.7% (2/53), respectively. Clinical and angiographic follow-up was available in 44 (83%) patients for 104 (83.2%) aneurysms for a mean duration of 16.2 months (range 3–51 months). According to the last angiographic follow-up, overall occlusion rates were complete in 85 (81.7%), near complete in 8 (7.6%), and incomplete in 11 (10.5%) aneurysms.

Conclusions Single-stage endovascular treatment of multiple aneurysms with combined endovascular techniques is technically feasible and increases the treatment possibility of all detected aneurysms. However, the safety of the procedure is controversial due to relatively high complication rates. In particular, in patients with bilateral internal carotid artery aneurysms, staged therapy may be used instead of simultaneous treatment with flow diverters to avoid thromboembolic events.