Efficacy of intraductal placement of nonflared fully-covered metal stent for refractory perihilar benign biliary strictures: A multicenter prospective study with long-term observation

Background: Endoscopic fully-covered self-expandable metal stents (FCSEMSs) are used to treat benign biliary strictures (BBSs); however, treatment for perihilar BBSs is technically challenging. The aim of this study was to evaluate the usefulness of an unflared FCSEMS designed for intraductal placement in patients with refractory perihilar BBS. Methods: Twenty-two consecutive patients with perihilar BBS unresolved by endoscopic plastic stent placement at 13 tertiary medical centers were prospectively enrolled. The FCSEMS was placed above the papilla and removed after 4 months. The primary outcome was stricture resolution at 4 months, and the secondary outcomes were technical success, stent removal, adverse events, and recurrence. Results: The technical success rate of intraductal FCSEMS placement was 100%, and plastic stent placement at contralateral or side branch was performed in 86% of patients. The rate of successful stent removal at 4 months was 100%, and stricture resolution was observed in 91% of patients. Stent migration or stent-induced de novo stricture did not occur in any patient. The stricture recurrence rate was 16%, and the median (interquartile range) follow-up duration was 2.8 (1.6-3.3) years. Conclusions: Intraductal placement of unflared FCSEMS is effective treatment for refractory perihilar BBS.