There are many children who, because of misdiagnosis, wait until the common bile duct cyst is found to be perforated, at which time the bile in the bile duct flows into the abdominal cavity and the whole abdominal cavity is extremely inflamed, at which time the child faces the danger of severe infection, electrolyte disorders, etc., and is very weak, and at which time the surgical bleeding will be very high, and most importantly, the abdominal adhesions are serious, making the surgery difficult. At this time, you can choose to perform external biliary drainage to drain the bile from the bile duct out of the body, so that the child can gradually recover, drain for 1-3 months, and then perform radical choledochal cystectomy. The external biliary drainage is now explained. 1.Distal bile duct, protein embolus (stone) in the bile duct blocking the bile outlet, resulting in bile stagnation in the common bile duct, increased tension, perforation and rupture of the common bile duct, and bile into the abdominal cavity. 2, External biliary drainage: the bile produced by the liver is continuously drained out of the body. 3, the intra-abdominal omentum begins to wrap the drainage tube and gradually fibrosis, forming another fistula outside the T-tube. If the T-tube is inadvertently dislodged at this time, a hose can be promptly implanted along the opening of the abdominal wall drainage, and the drainage can be continued (of course, it is better to protect the tube well). The bile drained from the drainage tube is sometimes cloudy and sometimes clear, sometimes yellow and sometimes green, sometimes very large and sometimes small, sometimes very thick and sometimes thin. These are all normal and are also related to the food you usually eat. As long as the drainage tube is protected and continuous drainage can be ensured, you will be able to recover soon.