Functionalized bioresorbable biliary stents: materials design, coating engineering, and clinical translation

Biliary strictures remain a major therapeutic challenge because conventional plastic and self-expandable metal stents are limited by occlusion, repeat intervention, migration, and tumor ingrowth. Bioresorbable biliary stents offer temporary mechanical scaffolding and, when functionalized, can also provide local therapeutic delivery without permanent foreign-body retention. This review focuses on the engineering decisions that determine whether these devices can move beyond descriptive promise toward indication-specific translation. We compare polymeric and emerging metallic biodegradable platforms, distinguish in vitro, preclinical in vivo, and expected real-bile degradation behavior, and critically evaluate the trade-offs among radial force retention, flexibility, fatigue resistance, radiopacity, drug release, biofilm resistance, manufacturability, and clinical readiness. Current evidence suggests that polydioxanone (PDO)- and copolymer-based designs may be more suitable for benign or post-surgical indications requiring temporary support, whereas malignant obstruction may require longer patency, stronger radial force, and carefully controlled antiproliferative or chemotherapeutic release. However, available human data include selected cohorts and registries but remain limited in comparative strength, so claims regarding long-term efficacy, quality of life, and cost-effectiveness should remain cautious until larger comparative trials are available.