Hepatoprotective therapy: Preoperative assessment of liver function and hepatoprotective therapy is important in patients with longer-term, severe jaundice, especially in patients who may undergo extensive hepatic, biliary, or pancreatic resection. Some lesions with localized conditions that are still resectable are overwhelmed by the inadequate reserve state of the liver and the opportunity for surgery is lost. Patients with adequate preoperative preparation, some with complex, long and extensive surgeries, can still pass through the perioperative period smoothly. Preoperative preparation is a prerequisite to ensure the safety of surgical performance and to reduce complications and morbidity and mortality rates. The following conditions indicate poor liver function and contraindication to combined liver surgery, especially contraindication to hepatic or pancreatic resection of more than half of the liver: A. Total serum bilirubin above 256 μmol/L; B. Human albumin below 35 g/L; C. Prothrombin activity below 60%, time prolongation greater than 6s, and difficult to correct after 1 week of vitamin K injection. ④ Indocyanine green contour test (indigocyanogreentest) was abnormal. Preoperative CT was applied to measure the volume of the whole liver and the volume of the liver to be resected, and calculate the volume of the preserved liver, which can help to assess liver function in the proposed radical resection of enlarged hilar cholangiocarcinoma. In addition, glucose tolerance test and prealbumin (preprotein) measurement are helpful for estimation of liver function of patients. Preoperative hepatoprotective therapy is necessary, but if biliary obstruction cannot be released, relying on pharmacological hepatoprotective therapy alone is not effective. Currently, commonly used drugs aim to lower transaminases, replenish energy, and increase nutrition. Hypertonic glucose, human albumin, branched-chain amino acids, glucuronolactone (glucuronide), pantodecalinone (coenzyme Q10), vitamin K, and high-dose vitamin C are commonly used. Pre-operative hepatoprotective treatment should also pay attention to avoid the use of drugs that are damaging to the liver. Surgical methods: The surgical methods of bile duct cancer resection are generally based on the location and staging of the tumor. Type IV tumor invades widely and is difficult to resect, so total hepatectomy and liver transplantation can be considered. The caudate lobe is located behind the first hepatic hilar and its hepatic duct is short and close to the confluence of the hilar bile ducts. The distant metastasis of cholangiocarcinoma in the hilar region occurs later, but infiltration and spread along the bile duct and peri-bile duct tissues are very common. All bile duct cancers invading above the confluent hepatic duct are likely to invade the caudate lobe hepatic duct and liver tissue, with one group reporting 97% of cases. Therefore, caudate lobectomy should be the main component of radical resection for cholangiocarcinoma in the hilar region. Cholangiocarcinoma cells can either infiltrate directly or metastasize into the intra- and extra-hepatic bile ducts and connective tissue of hepatoduodenal ligament through blood vessels and lymphatic vessels or through the perineural space. Therefore, careful dissection and removal of nerve fibers and nerve plexus in the hilar region, sometimes even including the right abdominal ganglion, during surgical resection of cholangiocarcinoma should be one of the basic requirements for radical resection of cholangiocarcinoma. At the same time, the connective tissue in the hepatoduodenal ligament should be removed as thoroughly as possible together with the fatty lymphoid tissue to realize the “skeletonization” of the vessels in the hilar region. In recent years, the surgical resection rate of cholangiocarcinoma of the hilar region has been significantly improved, and the resection rate has increased from 10% in the past to about 50%.