Long-term clinical and radiologic results of small cerebral aneurysms embolized with 1 or 2 detachable coils

BACKGROUND: Small cerebral aneurysms embolized with only 1 or 2 detachable coils often seem unstable and unsatisfactory. We tried to assess the long-term results of such embolized aneurysms. METHODS: Among 231 intracranial saccular aneurysms embolized at the Asan Medical Center between July 1995 and July 2004, 27 small aneurysms were occluded with only 1 (n = 12) or 2 (n = 15) detachable coils. Clinical and radiologic results were evaluated retrospectively for the involved patients. RESULTS: For the 1- and 2-coiled aneurysms, respectively, the mean dome sizes were 3.0 and 4.6 mm and the mean neck sizes were 1.9 and 2.7 mm. Most of the aneurysms were in the posterior circulation (19/27, 70%) and were found after bleeding (17/27, 63%). At the end of the embolization, complete occlusion in 19 aneurysms, residual neck in 1 aneurysm, and residual aneurysm in 7 aneurysms were attained angiographically. The mean packing ratios were 17.9% and 20.7% for the 1- and 2-coiled aneurysms, respectively. The mean clinical follow-up period of the patients was 41 months. No patient showed evidence of rebleeding; in addition, 1 patient with 1 coil and 2 patients with 2 coils were not followed up after discharge. Among the 10 follow-up DSAs or MRAs acquired after more than 8 months, radiologic major recurrences were detected in 2 patients after 10 and 15 months and second embolizations were done. CONCLUSIONS: Although the 1- and 2-coiled small aneurysms with a relatively low packing ratio seemed unstable, they showed a relatively low incidence of rebleeding and recurrence.