Temporary sphincter-preserving covered biliary stent with a frontal umbrella-shaped occlusive mechanism for common bile duct stone removal.

Currently, endoscopic retrograde cholangiopancreatography (ERCP) has been established as standard treatment for common bile duct (CBD) stones. However, this procedure requires endoscopic sphincterotomy (EST), which compromises function of the sphincter of Oddi and may lead to adverse events (AEs) such as bleeding, perforation, biliary reflux of intestinal contents, and stone recurrence. It is particularly unsuitable for patients requiring long-term anticoagulation therapy. In light of this, several researchers, including our team, have attempted to place a self-expandable metal stent (SEMS) in the distal CBD prior to stones clearance as an alternative to EST. Nevertheless, widespread adoption of this strategy has been limited by the issue of stone impaction between the stent and CBD wall. To address this, our team developed a temporary sphincter-preserving covered biliary stent (TSP-CBS) device equipped with a frontal umbrella-shaped occlusive mechanism. The open/close operation of this umbrella component effectively prevents stone impaction as described above. This study first validated safety of TSP-CBS in four porcine models, with no intraoperative or postoperative AEs observed. Subsequently, we performed two clinical cases of EST-free ERCP using TSP-CBS for CBD stone removal. Both procedures successfully cleared the stones. One patient developed postoperative hyperamylasemia, which resolved with conservative management, and no other intraoperative or postoperative AEs occurred. In summary, this preliminary study demonstrates the safety and feasibility of TSP-CBS for performing EST-free ERCP in patients with CBD stones. Further validation in larger clinical cohorts is warranted.