Endovascular coil embolization of very small intracranial aneurysms

Objective: We aimed to evaluate the results of endovascular coil embolization for very small aneurysms (≤ 3 mm). Materials and Methods: Between March 2005 and December 2008, a total of 31 very small aneurysms in 30 patients were treated by coil embolization. Of the 31 aneurysms, five (16%) were ruptured, as opposed to 26 (84%) that were not. We assessed the procedural complications, immediate angiographic outcome after coiling, clinical outcome, and follow-up MR angiography (MRA). Results: Two thromboembolic complications occurred during the procedure, but did not lead to any persistent neurologic deficit. No procedural aneurismal rupture was observed and procedure-related morbidity and mortality were both 0%. Occlusion was adequate in 25 aneurysms (81%) and incomplete in six aneurysms (19%). The clinical outcomes of five patients with ruptured aneurysms were good (Glasgow outcome scale ≥ 4), with no bleeding of the treated aneurysms during a mean follow-up period of 13.3 months. On 27 follow-up MRA, there was no recurrence, and the five incompletely occluded aneurysms showed a spontaneous amelioration resulting in an adequate occlusion. Conclusion: Coil embolization of very small aneurysms is technically feasible with good results. The long-term efficacy and the potential as a standard treatment strategy remain to be determined by randomized large trials.