Outcomes of a novel biliary hybrid metal stent composed of an inner-covered and an outer-uncovered stent for unresectable distal malignant biliary obstruction

Aims Uncovered self-expandable metal stents (SEMS) are prone to tumor ingrowth, whereas covered SEMS carry the risk of migration. We evaluated the feasibility of a newly developed biliary hybrid SEMS, designed to prevent both issues, for patients with unresectable distal malignant biliary obstruction (MBO). Methods Eighty patients with unresectable distal MBO underwent endoscopic placement of the hybrid SEMS (Two-in-One stent; Taewoong Corp., Goyang, Korea). This stent consists of an inner silicone-covered SEMS and an outer-uncovered SEMS. In cases of inner-covered SEMS dysfunction, it can be endoscopically removed while leaving the uncovered SEMS in place. Results Stent placement was successful in all patients (80/80), with clinical success in 98.8% (79/80). Inner-covered stent dysfunction occurred in 28.9% (22/76), primarily due to biliary sludge (90.9%, 20/22). No stent migration or bile duct kinking occurred. Mean cumulative patency of the inner-covered and the Two-in-One stents were 537.5 days (95% confidence interval (CI), 433.8–641.2) and 778.7 days (95% CI, 709.6–847.8), respectively. The 6-, 12-month, and lifetime patency rates of the Two-in-One stent were 94.0%, 86.4%, and 78.9%, respectively. Early and late adverse events were observed in six patients (four with pancreatitis and two with cholecystitis) and 27 patients (22 with recurrent biliary obstruction [RBO] and five with non-RBO) patients, respectively [ 1 ] [ 2 ] [ 3 ] [ 4 ] [ 5 ] [ 6 ] [ 7 ] [ 8 ] [ 9 ] [ 10 ] [ 11 ] [ 12 ] [ 13 ] [ 14 ] [ 15 ] [ 16 ] [ 17 ] [ 18 ]. Conclusions The Two-in-One stent demonstrates a high lifetime patency rate in patients with unresectable distal MBO, initially functioning as a non-migrating, partially covered SEMS and later transforming into an uncovered SEMS after removal of the clogged inner-covered SEMS. Publication History Article published online: 05 June 2026 © 2026. European Society of Gastrointestinal Endoscopy. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany