Abstract
Background: Although endovascular therapy for large unruptured basilar tip aneurysms (BTAs) has been applied by using various techniques, still the condition is difficult to treat completely because of its high recurrence and retreatment rate. We compared different endovascular techniques for the treatment of large unruptured BTAs.
Methods: A retrospective study was conducted in 18 patients (12 women; mean age, 63.5 years) with large BTAs treated by using endovascular techniques between 2005 and 2014. We categorized the endovascular techniques into 3 groups as follows: 1) coil-only group, without any stent; 2) S-stent group, with a stent from the unilateral posterior cerebral artery (PCA) to the basilar artery (BA); and 3) Y-stent group, with 2 stents from the bilateral PCAs to the BA placed in a Y-shaped configuration. The bifurcation angle between the bilateral PCAs was also measured. We evaluated the initial embolization and radiological follow-up results.
Results: The mean aneurysm size and dome-to-neck ratio were 11.7 mm (10-15 mm) and 1.9 (1.5-2.5). The overall initial embolization results showed complete occlusion in 27.8% of the patients, neck remnant (NR) in 44.4%, and body filling in 27.8%. The overall radiological follow-up results showed unchanged status in 27.8% of the patients, improved status in 5.6%, minor recurrence in 16.7%, and major recurrence in 55.6%. The mean bifurcation angles in the S- (189.6° [156°-228°]) and Y-stent groups (198.8° [172°-224°]) were greater than that in the coil-only group (160.4° [135°-189°]). The mean post-treatment radiological follow-up period was 21 months (1-52 months) in the coil-only group, 12 months (8-15 months) in S-stent group, and 22 months (12-43 months) in the Y-stent group. Although the initial embolization results did not significantly differ between the technical groups, the recurrence rate was significantly lower in the Y-stent group than in the other two groups (p = 0.02). Additional treatments were performed, four in the coil-only group and one in the S-stent group. Three patients in the Y-stent group showed a change in bifurcation angle after treatment. Two procedural complications were observed, namely intraoperative hemorrhage in the coil-only group and asymptomatic thromboembolic stroke in the Y-stent group. Two patients in the coil-only group had aneurysmal hemorrhage after treatment.
Conclusion: Y-configuration stenting is one of the most important treatment techniques for large unruptured BTAs because it is safe and may improve the anatomical outcome in the medium and short terms.
