I. What is transoral lithotripsy? Simply put, it is the removal of bile duct stones through a mirror under the mouth. Retrograde cholangiopancreatography (ERCP) is first performed by inserting a fiberoptic duodenoscope through the mouth to the papilla where the pancreaticobiliary ducts of the duodenum converge, inserting a catheter to the papillary opening, and injecting a contrast agent followed by x-ray radiography to show the bile ducts. Endoscopic papillary sphincterotomy (EST) was performed under the scope, and then a special mesh basket was inserted into the bile duct to snare the gallstone and remove it from the mouth. Choledochal stones <1 cm in diameter can be removed by EST; stones >1 cm in diameter can be removed after lithotripsy if necessary. The duodenoscopic technique does not require incision, is minimally painful, does not require anesthesia or intravenous analgesia, and removes choledocholithiasis through the mouth, and is reproducible and can be removed in multiple passes. It can also be applied for the treatment of a dozen diseases such as acute severe cholangitis, biliary pancreatitis, papillary sphincter stenosis and dysfunction. The procedure is similar to gastroscopy, and the patient is not in significant pain. Generally speaking, the patient can be discharged from the hospital about 3 days after the operation. Second, which patients are suitable for transoral stone extraction? 1.Patients with primary bile duct stones. 2.Patients with secondary common bile duct stones after cholecystectomy. 3.Patients with common bile duct stones who are older and have relatively poor systemic cardiopulmonary function cannot tolerate anesthesia, open or lumpectomy surgery, etc. 4.Patients with common bile duct stones who have undergone open upper abdominal surgery or multiple abdominal surgeries and are expected to have difficulty in performing open or laparoscopic surgery again. Who are not suitable for transoral stone extraction? 1.Patients who have upper gastrointestinal stenosis or obstruction, and it is estimated that it is impossible to reach the descending duodenum. 2. Those who have severe cardiopulmonary insufficiency and other contraindications to endoscopy. 3.Non-stone embedded acute pancreatitis or acute attack of chronic pancreatitis. 4.Patients with bile duct stricture or obstruction and cannot be placed for bile duct drainage. 5.For those with severe iodine allergy, non-ionic contrast agent can be used instead, but intraoperative and postoperative emergency preparations should be made. 6.Stone diameter >2cm 7.Non-preferred method for younger patients. 8, Gallbladder stones or intrahepatic stones cannot be used by this method. 9.After gastrointestinal diversion surgery.