Targeting the sac or the feeders? An anatomy-driven review of contemporary embolization strategies of type II endoleaks.

Endovascular aortic repair (EVAR) has become the primary treatment for abdominal aortic aneurysms; however, type II endoleaks (T2ELs) remain the most frequent post-procedural complication, with variable clinical significance and management strategies. This review synthesizes current evidence on the natural history, diagnostic evaluation, and treatment of T2EL, with a focus on the comparative roles of aneurysm sac and feeder embolization. Available data indicate that T2ELs represent a heterogeneous condition that often follows a benign course with a substantial rate of spontaneous resolution, whereas a clinically significant subset is associated with aneurysm sac enlargement requiring intervention. Across studies, treatment outcomes appear to be driven primarily by anatomical complexity and flow patterns rather than by the choice of embolization technique alone. Transarterial embolization remains the most commonly used first-line approach, whereas direct sac puncture has demonstrated higher technical and clinical success rates in selected complex cases. However, direct comparison between strategies is limited by heterogeneity in outcome definitions, study design, and follow-up protocols. Nevertheless, we present an anatomy-driven decision algorithm for selecting the embolization method based on the T2EL complexity. These findings support a shift from technique-centered to anatomy-driven therapeutic decision-making. In selected cases with limited inflow, feeder embolization may be sufficient, whereas complex endoleaks with multiple collateral pathways often require direct or indirect sac embolization to achieve durable exclusion. An individualized, anatomy-based treatment strategy appears to provide the most rational framework for optimizing outcomes in patients with T2EL.