A novel gallbladder umbrella stent (the Shai™ Stent) for prevention of stone migration and impaction: results on feasibility and short-term safety in a porcine model

Background and aims: Cholelithiasis is the most common biliary tract disorder. Surgery is the treatment of choice for symptomatic gallstones. Aims of this study were to investigate the feasibility and short-term safety of a new endoscopic procedure with a specially designed Nitinol gallbladder stent for blockage of gallstone migration, the Shai™ Stent. The Shai stent is designed to enable free bile flow, which will be supposed to prevent recurrent attacks. Methods: The Shai™ Stent was inserted into the gallbladder during a standard ERCP procedure using a conventional metal stent delivery system. The aim of the present study was to investigate the feasibility and safety of insertion and deployment and removal of the stent into the gallbladder of pigs. In addition, the short-term safety of the stent was evaluated. Results: Fifteen stents were placed in the gallbladder of 15 pigs. Mean procedure time was 25 min (15–37). The maximum follow-up before sacrifice was 42 days. The stent in 1 pig had migrated at the 42 days follow-up but there were no macroscopic changes in its gallbladder or other organs. The stent remained in place in the remaining 12 pigs at autopsy, and the gallbladder and bile ducts were macroscopically normal. Stent removal was easily done in two pigs immediately after placement. Conclusions: Correct placement and removal of the Shai™ Stent in the gallbladder is safe and feasible in pigs. Further clinical trials are warranted to confirm these results and to effectively evaluate the capability of this stent as an innovative biotechnology to block gallstones from migration and impaction.