title: Surgical anatomy of hepatic hilum with special reference of the plate system and extrahepatic duct.
abstract: BACKGROUND
  When 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.
  
  
  METHODS
  Twenty-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.
  
  
  RESULTS
  The 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.
  
  
  CONCLUSIONS
  The 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.
authors.affiliation: Second Department of Surgery, Yokohama City University School of Medicine, 3-9 Fukuura Kanazawa, Yokohama City, Kanagawa 236-0004, Japan. hmasunari@miyakotoku.com
authors.forename: Hideki
authors.initials: H
authors.lastname: Masunari
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Shimada
authors.forename: Itaru
authors.initials: I
authors.lastname: Endo
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Fujii
authors.forename: Kuniya
authors.initials: K
authors.lastname: Tanaka
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Sekido
authors.forename: Shinji
authors.initials: S
authors.lastname: Togo
mesh_terms: D000328:Adult; D017734:Bile Ducts, Extrahepatic / Q000033:anatomy & histology* / Q000601:surgery; D002102:Cadaver; D002763:Cholecystectomy; D006498:Hepatectomy; D006801:Humans; D008099:Liver / Q000033:anatomy & histology* / Q000601:surgery