Results of Endovascular Coil Embolization Treatment for Small (≤ 5 mm) Unruptured Intracranial Aneurysms

Abstract

OBJECTIVE Researchers and clinicians have been unable to fully elucidate the natural course of and proper treatment for unruptured intracranial aneurysms (UIAs) smaller than or equal to 5 mm, particularly with regard to whether close observation or surgery is more appropriate. In this retrospective study, we evaluated the safety and efficacy of endovascular coil embolization of small (≤ 5 mm) asymptomatic UIAs by analyzing outcomes and complications associated with the procedure. MATERIALS AND METHODS We analyzed data from 150 patients with small asymptomatic UIAs (≤ 5 mm) treated with coil embolization between January 2011 and December 2015. Three-dimensional angiography was used to measure aneurysm size. We evaluated procedure-related morbidity and mortality, immediate post-operative angiographic results, brain computed thomography follow-up results on post-operative day one, and clinical progress. RESULTS UIAs occurred primarily in the anterior circulation area (142 cases, 94.67%), though eight patients exhibited UIAs of the posterior circulation. Following coil embolization, aneurysms with complete occlusion were observed in 137 cases (91.3%). Partial occlusion occurred in five cases (3.33%), while the procedure had failed in eight cases (5.33%). Procedure-related morbidity and mortality were five cases (3.33%) and zero cases, respectively. CONCLUSION The endovascular treatment of small asymptomatic UIAs is associated with good short-term outcomes without permanent neurologic complications as well as low overall complication and morbidity rates. Thus, the procedure should be considered for patients with smaller asymptomatic UIAs.