Comparison of flow diversion alone or combined with coiling for treatment of intracranial very large and giant aneurysms.

Objective: To compare the clinical and angiographic outcomes of flow diverter (FD) combined with coiling versus FD alone for intracranial very large (>2 cm) and giant aneurysms.

Methods: A retrospective analysis was conducted on 76 patients with intracranial very large/giant aneurysms treated at a single institution (April 2015-June 2024). Patients were divided into two groups: FD combined with coiling (FD + coiling group, n = 55) and FD alone (FD alone group, n = 21). Immediate occlusion rates, perioperative complications, and follow-up outcomes were compared. Aneurysm occlusion was determined using the O'Kelly-Marotta (OKM) grading system.

Results: The FD + coiling group demonstrated significantly higher complete or subtotal immediate postoperative occlusion (36.4 % [20/55] vs. 4.8 % [1/21], P = 0.006) and lower overall perioperative complications (12.7 % [7/55] vs. 38.1 % [8/21], P = 0.031), particularly hemorrhagic complications (1.8 % [1/55] vs. 19.0 % [4/21], P = 0.028) with comparable mortality (3.6 % vs. 4.8 %) and disability rates (3.6 % vs. 4.8 %). At median 188-day follow-up (IQR 156-209), the FD + coiling group maintained higher complete or subtotal occlusion rates (92.1 % [35/38] vs. 46.7 % [7/15], P = 0.001). All 53 patients achieved favorable outcomes (modified Rankin Scale score ≤ 2).

Conclusion: For very large/giant intracranial aneurysms, FD combined with coiling demonstrates higher immediate occlusion rates, fewer perioperative complications, and improved early-to-mid-term occlusion occlusion compared to FD alone.