A Retrospective Comparative Study of Leo Baby and Atlas Stents for the Treatment of Intracranial Aneurysms: Embolization Outcomes and Complications.

Intracranial aneurysms (IAs) are increasingly managed with endovascular techniques, with stent-assisted coiling offering superior outcomes for complex morphologies. The Neuroform Atlas (laser‑cut, open‑cell) and Leo Baby (braided, closed‑cell) are low‑profile stents deployable through small microcatheters, improving navigability in tortuous vasculature. However, direct comparative data on their relative efficacy and safety remains scarce. This retrospective study compares embolization outcomes and procedure‑related complications between the two devices. A total of 96 patients with IAs treated with stent-assisted coiling between January 2022 and December 2023 were enrolled: 46 received Atlas and 50 received Leo Baby. Baseline demographic and aneurysm characteristics were comparable between groups. Immediate post‑procedural angiography demonstrated similar complete occlusion rates (Atlas 89.1% vs. Leo Baby 88.0%; P = 0.3281), and no significant difference was found in Raymond grade distribution at 6‑month follow‑up (P = 0.5067). Favorable outcomes (modified Rankin Scale score 0-2) at 1 year were achieved in >90% of patients in both cohorts (P = 0.1528). Peri-procedural complications showed no statistically significant difference between the two groups (28.2% vs. 12.0%; P = 0.0857); however, post-hoc power analysis revealed that the current sample size provided only 42% power to detect this observed difference, indicating a high risk of Type II error. In conclusion, these findings suggested that both Atlas and Leo Baby stents afford similar angiographic and clinical efficacy for IA embolization; however, the numerically higher complication rate observed with the Atlas stent should be interpreted with caution due to insufficient statistical power, and our results should be considered hypothesis-generating rather than confirmatory. Further largescale, prospective multicenter studies are warranted to confirm these observations and refine device selection in clinical practice.