2026 Volume 40 Issue 1 Pages 57-68
Covered self-expandable metallic stents (CSEMSs) were developed to overcome tumor ingrowth, a major limitation of uncovered stents in malignant biliary obstruction. The 30-year technological competition between Korean companies M.I.Tech and Taewoong Medical has driven innovations including the Hook-and-cross structure, which optimizes axial force properties. While CSEMSs significantly reduce tumor ingrowth compared to uncovered stents, they introduce new challenges including stent migration, sludge occlusion, and tumor overgrowth.
Various countermeasures have been implemented, including braided-type structures for enhanced flexibility, optimized flare designs to prevent migration, and anti-reflux mechanisms to reduce sludge formation. Recent meta-analyses demonstrate that partially covered stents may offer superior patency compared to fully covered designs by balancing ingrowth prevention with migration resistance.
Next-generation technologies are emerging, including drug-eluting stents for active tumor suppression, biodegradable stents for benign strictures, and 3D-printed patient-specific designs guided by computational fluid dynamics. These innovations represent a paradigm shift from passive bile drainage devices to active therapeutic platforms. The field of biliary stenting stands at a transformative juncture, moving toward personalized, functionally optimized interventions that promise improved patient outcomes.
