Surgical anatomy of the hepatic hilar area

It is important to understand the main variations of the biliary and vascular elements inside the plate system for hilar bile duct carcinoma because all variations of these elements occur in this plate system. The plate system consists of the hilar plate, cystic plate, and umbilical plate which cover the extrahepatic vascular system and are fused with the hepatoduodenal ligament. The bile duct and vascular system that penetrate the plate system form Glisson's capsule in the liver, but the caudate branch and the medial segmental branch are exceptions. The bile duct and hepatic artery accompanying the plate system can be exfoliated from the portal vein with numerous lymph ducts and nerves. The bile ducts in the right hepatic lobe are classified into 4 types, and the standard type is present in 53-72% of cases. In the left bile duct, the medial segmental bile duct is connected in the vicinity of the hilar area in 35.5% of cases, and these cases should be treated the same as the caudate lobe in hilar bile duct carcinoma. Generally, there is little main variation of the portal vein (16-26%), but more variation in the hepatic artery (31-33%). During surgery for hilar bile duct carcinoma, it is important to observe the plate system and the many variations of the bile duct and vascular system.