The paradigm evolution of biliary stents: from passive drainage to intelligent diagnostic-therapeutic platforms.

The clinical management of biliary obstruction has long relied on mechanical drainage provided by stents, yet the inherent risks of re-occlusion, infection, and migration underscore the fundamental limitations of this passive support paradigm. This review proposes a four-stage paradigm evolution framework for biliary stent technology, demonstrating a shift from "passive physical support" to an "active therapeutic platform." The first stage, represented by plastic and self-expandable metallic stents, established anatomical drainage but is limited by biofilm deposition, tumor ingrowth, and migration. The first paradigm shift introduced functionalized stents incorporating drug-eluting, radionuclide, or photothermal/photodynamic coatings, transforming stents into active therapeutic carriers. The second paradigm shift emphasizes bio-adaptation through fully biodegradable stents achieving "temporary support followed by disappearance," alongside cell/matrix coatings to promote tissue regeneration. A third paradigm shift is emerging, focusing on intelligent responsiveness and personalization through closed-loop systems integrating biosensors, wireless communication, and artificial intelligence for real-time monitoring and on-demand therapy, combined with 3D/4D printing for patient-specific adaptation. Through critical assessment of each stage, this review dissects translational challenges including evaluation standards, long-term safety, cost-effectiveness, and regulatory complexities. Ultimately, we present a clinical decision-oriented technological spectrum delineating stent positioning across benign and malignant biliary diseases, envisioning future dynamic platforms integrating diagnosis, treatment, and monitoring to advance biliary intervention into an era of data-driven precision therapy. STATEMENT OF SIGNIFICANCE: This review establishes, for the first time, a four-stage paradigm evolution framework for biliary stent technology-from passive mechanical support to active functionalized intervention, bio-adaptive scaffolds, and ultimately intelligent diagnostic-therapeutic platforms. By systematically dissecting the irreconcilable contradictions inherent to each paradigm, this framework provides a design-philosophy navigational map that transcends conventional chronological classifications. The integration of materials science mechanisms, cross-technology quantitative comparisons, and evidence-based clinical decision pathways offers both clinicians and biomaterials researchers a comprehensive reference for understanding the past trajectory and future direction of biliary stenting.