Efficacy and complications of endovascular embolization for very small (3 mm or smaller) ruptured cerebral aneurysms

Objective: Endovascular embolization of very small aneurysms (under 3 mm in maximum diameter) is considered to be high risk for aneurysm perforation. Methods: We compared initial angiographic results of ruptured aneurysms between under 3 mm in diameter (21 cases, small group) and over 3 mm in diameter (85 cases, non-small group), the results of short-term follow-up angiography in the small group were also demonstrated. In the small group, extremely soft coils were mainly used for aneurysmal filing. Results: The technical success rates in the small and in the non-small groups were 95.2% and 100%, respectively. Initial angiographic results showed that complete occlusion was obtained in 65.0% of the small group and 52.9% of the non-small group. The mean packing densities in the small and non-small groups were 47.1±11.4% and 26.4±9.5%, respectively, showing the packing density in the small group was significantly higher than those in the non-small group (p