Surgical Anatomy of Hepatic Hilum with Special Reference of the Plate System and Extrahepatic Duct

Abstract

BackgroundWhen resecting hilar cholangiocarcinoma, the surgeon cannot visualize the hilar vessels through thick connective tissue known as the plate system. Little has been reported regarding the anatomical relationship between the plate system and the extrahepatic bile duct. MethodsTwenty-five formalin-fixed cadaveric livers were dissected carefully and 7 were sectioned sagittally. The extent, composition, and distribution of the extrahepatic bile ducts within the system were investigated. The length between the confluence of the hepatic duct and the branch point of the segmental duct (level I) and the length between the branch point of the segmental duct and the segmental Glisson’s pedicle (level II) were measured. ResultsThe plate system—composed of the hilar, cystic, Arantian, and umbilical regions—was easily separated from the hepatic parenchyma. Histologically, dense connective tissue with abundant capillaries, lymphatic vessels, and neural fibers were noted. Level I of B1pcp and B4a measured 13.0 and 14.7 mm, respectively. Level II measured 8.6 and 17.3 mm, respectively. ConclusionsThe bile ducts in the plate system correspond to the extrahepatic bile ducts and their lengths are variable for every segment. Knowing the lengths of the resectable extrahepatic bile ducts is useful for deciding which segment should be resected according to the cancerous invasion.