Treatment outcomes of large and giant intracranial aneurysms according to various treatment modalities

Purpose This study aimed to compare the treatment outcomes of large (15-25 mm) and giant (> 25 mm) intracranial aneurysms (IAs), according to different treatment modalities. Methods In total, 112 patients with large and giant IAs treated with various treatment modalities between January 2009 and December 2018 were retrospectively reviewed. Clinical and radiological parameters were analyzed and correlated with the treatment modality. Results A total of 141 procedures were performed on 112 patients. We initially treated 47 cases with coil embolization, 39 with flow diverter (FD), 13 with direct clipping, and 13 with parent artery occlusion (PAO). Recurrence (46.8%) and retreatment (31.9%) rates were significantly higher in the coiling group (p< 0.001). Complete occlusion rate (36.3%) was significantly lower in the coiling group (p= 0.027). PAO could achieve a high complete occlusion rate (90.9%) with low complication rate (12.5%). The total complication rate was 17%. In the multivariate logistic regression analysis, FD (OR 3.406,p= 0.036) and direct clipping (OR 5.732,p= 0.017) showed a significantly higher complication rate than coiling. The overall mortality rate was 8% (8/139 procedures). At the last follow-up (mean 30.6 +/- 26.4 months), 70 of 96 patients (72.9%) showed complete or near-complete occlusion. Good functional outcome (mRS <= 2) was observed in 90 of 112 (80.3%) patients at the last follow-up (mean 33.2 +/- 30.5 months). Conclusions Good clinical and radiologic outcomes with acceptable complication and mortality rates can be achieved by various treatment modalities. The selection of appropriate modality should be individualized based on the angiographic findings and clinical symptoms.