Enhanced biocompatibility and efficacy of a newly developed plastic biliary stent: a porcine model study

Plastic stents are widely used in endoscopic biliary drainage. However, limitations such as poor conformability, migration, biofilm-induced obstruction, and limited radiographic visibility remain unresolved. This study aimed to evaluate the efficacy and safety of the newly designed stent using in vitro mechanical tests and an in vivo porcine biliary stricture model. All stents were classified into four groups: Group 1, commercial double pigtail; Group 2, new double pigtail; Group 3, proximal half-bend with distal pigtail stent; and Group 4, double half-bend stent. The drainage performance and mechanical properties were assessed using in vitro evaluations. A mini-pig biliary stricture model was used for i n vivo validation. Stents were endoscopically inserted and maintained for 4 weeks. Outcomes included radiographic migration, biochemical parameters, biofilm/sludge assessment, luminal patency, and histological analysis of bile duct tissue. Groups 3 and 4 showed favorable exploratory findings in tissue reactivity, luminal patency, and positional stability compared with Group 1. Stent migration occurred in 1/4 animals in Group 1 and in 0/4 animals in Groups 2–4. Because multiple structural modifications were introduced simultaneously, the observed findings could not be attributed to an individual design component. Radiopaque markers enhanced visibility under fluoroscopic guidance, facilitating real-time confirmation of the stent position. In this exploratory preclinical study, the newly developed stents showed favorable mechanical, histological, and luminal-patency findings. These results require confirmation in larger preclinical studies and prospective clinical investigations.