Early experience with Target Tetra coils for treatment of small and very small ruptured intracranial aneurysms

Background: Endovascular treatment of small (< 5 mm) and very small (≤ 3 mm) ruptured intracranial aneurysms remains technically challenging, historically carrying elevated procedural risks. Advances in coil technology, such as the Target Tetra Detachable Coil (TTDC), aim to improve embolization safety and efficacy. However, limited data exist on outcomes using TTDC coils specifically for ruptured aneurysms. Objective: To evaluate the safety, angiographic efficacy, and clinical outcomes of TTDC for small and very small ruptured intracranial aneurysms. Methods: We retrospectively analyzed 36 patients with ruptured intracranial aneurysms ≤5 mm treated using TTDC between 2023 and 2025 at a single center. Aneurysms were classified as small (n = 28) or very small (n = 8). Patient demographics, aneurysm characteristics, procedural details, angiographic outcomes, clinical outcomes, and complications were analyzed. Results: Median patient age was 57 years (IQR 43–73); 33.3% were male. The mean aneurysm dome height was 2.6 ± 0.9 mm, the mean neck diameter was 2.4 ± 0.7 mm, and the median dome-to-neck ratio was 1.0. Immediate complete occlusion (Raymond-Roy Class I) was achieved in 42.7% of aneurysms, and residual neck filling (Raymond-Roy Class II) in 25.0%. Follow-up imaging (mean 4.9 months) showed complete occlusion in 37.5% of aneurysms. Recanalization occurred in 29.2% of patients with repeat imaging and 6 (25%) requiring retreatment. Favorable clinical outcomes (mRS 0–2) occurred in 75.0%. Procedural complications occurred in 13.9% (five cases), including two intraprocedural perforations. No rebleeding occurred. Conclusion: Early experience with TTDC demonstrates safe, effective embolization for ruptured small and very small intracranial aneurysms, supporting the broader use of modern coils in these challenging lesions.