A pilot study of Spring Stopper Stents: Novel partially covered self-expandable metallic stents with anti-migration properties for EUS-guided hepaticogastrostomy

Background and Objectives: EUS-guided hepaticogastrostomy (EUS-HGS) is an effective salvage procedure when conventional endoscopic transpapillary biliary drainage is difficult or fails. However, the risk of stent migration into the abdominal cavity has not been resolved completely. In this study, we evaluated a newly developed partially covered self-expandable metallic stent (PC-SEMS) that has a spring-like anchoring function on the gastric side. Methods: This retrospective pilot study took place at four referral centers in Japan between October 2019 and November 2020. We enrolled 37 cases consecutively who underwent EUS-HGS for unresectable malignant biliary obstruction. Results: The rates of technical and clinical success were 97.3% and 89.2%, respectively. Technical failures included one case in which the stent was dislocated during the removal of the delivery system, requiring additional EUS-HGS on another branch. Early adverse events (AEs) were observed in four patients (10.8%): two with mild peritonitis (5.4%) and one each (2.7%) with fever and bleeding. No late AEs were observed during the mean follow-up period of 5.1 months. All recurrent biliary obstructions (RBOs) were stent occlusions (29.7%). The median cumulative time to RBO was 7.1 months (95% confidence interval, 4.3 to not available). Although stent migration in which the stopper was in contact with the gastric wall on follow-up computed tomography was observed in six patients (16.2%), no migration was observed. Conclusions: The newly developed PC-SEMS is feasible and safe for the EUS-HGS procedure. The spring-like anchoring function on the gastric side is an effective anchor preventing migration.