Innovation of EUS-guided transmural gallbladder drainage using a novel self-expanding metal stent

Endoscopic ultrasonography (EUS)-guided transmural drainage has been accepted as a modality of choice in peripancreatic fluid collection and acute cholecystitis. Each type of stent, including double-pigtail plastic stents, tubular self-expandable metal stents (SEMS), and lumen-apposing metal stents, for these procedure has its own advantages and disadvantages. To overcome their disadvantages, this animal study evaluated the feasibility of a newly designed twisted fully covered SEMS with spiral coiled ends. We performed the EUS-guided cholecystogastrostomy with a newly developed metal stent in eight mini pigs with surgically induced gallbladder distension. This novel stent is a twisted fully covered SEMS with spiral coiled ends, a diameter of 8 mm, and a length of 6 cm. The stent has been maintained for four to seven weeks after EUS-guided cholecystogastrostomy. The primary outcome was the technical success rate, and the secondary outcomes were adverse events, stent dysfunction, stent removability, and fistula formation. The stent was placed successfully between the gallbladder and the stomach in all cases without any adverse event. We observed neither stent migration nor dysfunction during the study period, and all the stents were removed easily as scheduled. We confirmed successful cholecysto-gastric fistula formation at endoscopic and histologic level in all cases. EUS-guided transmural drainage and fistula formation using a new twisted fully covered metal stent with spiral coiled ends was technically feasible without any adverse event in this animal study. Further clinical studies are needed to evaluate its efficacy and safety in real practice.