Tailored Surgical Approach for Moyamoya in Very Young Children: A Single-Center Retrospective Analysis and Algorithm Proposal.

Background and Objectives MoyaMoya Disease (MMD) is a progressive cerebrovascular disorder characterized by stenosis of the arteries of the circle of Willis with development of collateral vessels. When associated with other conditions, it is termed MoyaMoya syndrome (MMS). Recommendations for surgical interventions in pediatric cases remain limited. Early onset, especially in children younger than 3 years, is linked to poorer outcomes. Drawing from our institutional experience, we propose a treatment algorithm to optimize revascularization strategies in children, with particular focus on this high-risk subgroup. Methods A retrospective analysis was conducted on patients with MMD or MMS who underwent surgical revascularization before the age of 3 at our institution between January 2015 and July 2023. Data included demographics, clinical presentation, surgical techniques, complications, and outcomes. Results Sixteen patients underwent surgery. Transient ischemic attacks and seizures were the most frequent onset symptoms (45.7% each), followed by intellectual disability (25%). Magnetic Resonance Imaging (MRI) revealed ischemic lesions in 75% of cases and posterior circulation involvement in 5 patients. The mean surgical age was 2.1 ± 0.9 years. Indirect revascularization was the primary surgical approach, with two patients receiving a combined direct and indirect bypass. At follow-up (5.6 ± 1.8 years old), 50% remained asymptomatic. MRI showed improved perfusion in 66% of patients, and progression was observed in two. Conclusion Children under 3 with MMD/MMS present an aggressive clinical, "unstable" disease course, with higher rates of preoperative infarction, posterior cerebral artery (PCA) involvement, and recurrent strokes. These features correlate with poor outcomes, particularly when surgery is delayed, especially when surgery is delayed, likely due to the metabolic vulnerability of the immature brain. Given the lack of standardized surgical guidelines, our study supports early surgical intervention, using indirect or combined revascularization techniques. We propose a tailor algorithm on affacted vascular territories, incorporating direct bypass procedures, when feasible.