Endoscopic retrograde cholangiopancreatography (ERCP) combined with endoscopic papillary sphinctomy (EST) is the preferred clinical treatment for common bile duct stones, and this minimally invasive treatment technique has been widely used in clinical practice for decades. However, even after successful stone removal by EST combined with various methods, the incidence of postoperative recurrent bile duct stones can still be as high as 9.8%\~30% . The emergence of these long-term complications after EST surgery is currently thought to be related to the loss of Oddi sphincter function. In clinical practice, the investigators tried a new method to repair the Oddi sphincter, that is, after ERCP+EST stone removal, a metal clip was inserted into the endoscopic clamp through the duodenoscopy, and clamp precisely on both lateral edges of the nipple after incision. This procedure is called endoscopic nipple clipping (ECPP). Initial explorations in animal and human trials showed good results, with 3 weeks after clipping of the incised nipple not only showing scar repair of the nipple shape and structure, but also confirmed the recovery of sphincter function by Oddi sphincter manometry, the Oddi's sphincter basal pressure, contraction frequency and contraction amplitude were able to return to the pre-EST level. In summary, the investigators designed a single-center randomized controlled trial to explore and verify the clinical effect of ECPP on the prevention of recurrent bile duct stones within one year by comparing the incidence of recurrent bile duct stones within one year after EST surgery. By observing the changes of intestinal biliary reflux, biliary bacterial colonization, biliary microecology and bile metabolism after EST surgery, the pathogenesis of long-term complications such as recurrent bile duct stones after EST surgery was further sought.
Inclusion Criteria: * Imaging confirms the presence of common bile duct stones. * Common bile duct stones ≥ 1.0 cm in length. * Common bile duct inner diameter≥1.2cm. * The patient agrees to participate in the trial and signs the informed consent form. Exclusion Criteria: * Combined with coagulation dysfunction. * heart, lung, kidney or other serious organic diseases. * Patients with severe psychiatric illness. * Previous papillary sphincterotomy. * Patients who cannot cooperate with the completion of this study. * Those with a life expectancy of less than 1 year and may not be able to complete follow-up.