Progressive Occlusion and Recanalization After Endovascular Treatment for 287 Unruptured Small Aneurysms (<5mm): A Single-Center 6-Year Experience

ObjectiveWe aimed to investigate the effect of coiling for small unruptured intracranial aneurysms (UIAs) (<5 mm) on progressive occlusion and recanalization, and the dubious factors related to progressive occlusion and recanalization among UIAs without complete occlusion.MethodsA total of 264 patients with 287 small UIAs were coiled in our institution between June 2009 and December 2014. All UIAs were divided into small (3-5 mm) and very small (<3 mm) groups, and UIAs without initial complete occlusion were divided into progressive, stable, and recanalization groups. Baseline characteristics, procedure-related complications, angiographic follow-up results, and clinical outcomes were statistically analyzed.ResultsAmong 287 aneurysms, 211 aneurysms (73.5%) were completely coiled, 3 (1.2%) had intraoperative ruptures, and 12 (4.2%) had perioperative thromboembolic events. Angiographic follow-up was available for 174 patients (65.9%), and the incidence of recanalization was 5.7%. Among 56 aneurysms without complete occlusion, 43 (76.8%) had progressive occlusion and 6 (10.7%) had recanalization. Anatomic results of initial and follow-up between the small and very small groups were similar. On logistic regression analysis, smaller size (<3 mm) without complete occlusion related to recanalization (odds ratio, 8.0, 95% confidence interval 1.3-50.0; P = 0.026).ConclusionsOur study suggested that coil embolization of small UIAs can achieve a high rate of progressive occlusion and a low rate of recanalization during follow-up. Anatomic results of initial and follow-up between small (3-5 mm) and very small (<3 mm) groups were similar. Smaller size (<3 mm), without complete occlusion, may relate to recanalization.