EST is an operation using the Erbao electric knife and Three-cavity incision knife to make a large incision to the duodenal nipples，and the incision scope is the nipple mouth uplift length of 4/5. It has been used since 1974. The technique is intuitive and intact. However, EST cut too small to achieve the purpose of treatment and will affect the next step, and if the incision is too large it may be easier to occur gastrointestinal perforation and bleeding.The EST will also damage the anatomy of the Oddi sphincter structure,which causes bacterial reflux to the bile duct, the recurrence of CBD.Some surgeons prefer it because it's postoperative pancreatitis rate is lower and it may be easier to find the lesion position if bleeding or perforation occurs.

EPBD is an operation using the Columnar expansion balloon to expand duodenal to achieve the purpose of using the basket and other instruments to take stone out. Balloon expansion may retain part of the sphincter not destroyed, and basically retain the normal physiological function of the nipple sphincter.Thus it may reduce the risk of recurrence of stones and bacterial reflux. However,the postoperative pancreatitis rate is high(4.8% -19.5% ), and nipple sphincter tear is uncontrollable in EPBD.If the digestive tract perforation or bleeding occur after EPBD,it is hard to accurately find the lesion position.Some surgeons prefer it for it's lower bleeding and perforation rate.

sEST+EPBD is an operation combining EST and EPBD. Investigators use the Erbao electric knife and Three-cavity incision knife to make a small incision to the duodenal nipples, and the incision length is less than 5mm while the incision scope is less than the nipple mouth uplift length of 1/2. Then, Investigators match the appropriate Columnar expansion balloon according to the diameter of the common bile duct and gradually expand the duodenal nipples.This method allows the nipple sphincter to be cut in a small range, then the balloon can guide the direction of the nipple sphincter tearing after the expansion , so that the digestive tract bleeding, perforation may be smaller and more controllable. Besides,it may reduce postoperative pancreatitis rate and the recurrence rate of stones.

Erbao electric knife is used to cut the Duodenal sphincter

Investigators comprehensively assess whether the hemorrhage, perforation, pancreatitis and other complications of retrograde cholangiopancreatography (ERCP) happen or not by clinical sympton and blood index 1 day after the ERCP. The blood index includes CRP, amylase,lipase,leukocyte,red blood cell,hemoglobin.Besides,CT will be done if necessary.Finally investigators use statistical method to analyse the incidence of composite events of infection, hemorrhage, perforation, pancreatitis.

One year after the ERCP,the participants will have a CT scan to find out whether the bile duct stones recur again.