In this multicenter, randomized trial, patients with cholelithiasis with concomitant choledocholithiasis based on inclusion and exclusion criteria will be randomly assigned to receive rectal indomethacin alone or the combination of indomethacin plus a prophylactic pancreatic stent after endoscopic transpapillary gallbladder-preserving cholecystolithotomy.Clinical data and patient-reported outcomes are regularly collected at baseline and during follow-up periods. The study aims to analyze the impact of pancreatic duct stent implantation on the incidence of post-ERCP pancreatitis in gallstone patients treated with ERCP-GPC by comparing the efficacy differences between the experimental and control groups. Additionally, the study investigate the effects of pancreatic duct stent placement post-ERCP on other postoperative complications, conduct a comparative analysis of the economic benefits of placing versus not placing pancreatic duct stents after ERCP, and develop effective clinical strategies for preventing pancreatitis after gallbladder-preserving stone extraction in gallstone patients.

Inclusion Criteria:

1. Patients aged 18 years or older;
2. Patients with gallbladder stones and common bile duct (CBD) stones confirmed by ultrasound and/or MRCP or other imaging modalities (CT/MRI);
3. Patients with every gallbladder stone ≤1 cm in diameter or sludge-like stones;
4. Patients without a history of gastrointestinal reconstruction surgery,cholecystectomy or previous biliary surgery, includes ERCP;
5. The morphology and size of the gallbladder are essentially normal and the thickness of the gallbladder wall is ≤3 mm;
6. Patients with at least one of the following high-risk factors for post-ERCP pancreatitis (PEP): suspected sphincter of Oddi dysfunction (SOD), female sex, history of pancreatitis, difficult cannulation (defined as ≥5 cannulation attempts or ≥5 minutes of cannulation time), pancreatic duct contrast injection, age <35 years, non-dilated extrahepatic bile duct, no history of chronic pancreatitis, normal serum bilirubin, precut sphincterotomy, biliary balloon dilation, incomplete bile duct stone clearance, or intraductal ultrasound ;
7. Patients who voluntarily provide signed informed consent.

Exclusion Criteria:

1. Patients with any of the following diagnoses: chronic atrophic cholecystitis, porcelain gallbladder, suspected gallbladder malignancy, or Mirizzi syndrome;
2. Patients with ectopic duodenal papilla or congenital pancreaticobiliary malformations;
3. Patients unfit for ERCP endoscopic treatment due to severe systemic diseases;
4. Patients with severe coagulation dysfunction (defined as an International Normalized Ratio [INR] >1.5) or significant thrombocytopenia (platelet count <50×10⁹/L);
5. Pregnant women;
6. Patients with guidewire entry into the pancreatic duct ≥3 times during the procedure;
7. Patients with allergies to aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs);
8. Patients with congenital or acquired absence of the rectum;
9. Patients with severe acute pancreatitis