title: Six rare biliary tract anatomic variations: implications for liver surgery.
abstract: OBJECTIVE
  The variations in the anatomy of the biliary tract need to be recognized in modern liver surgery. The purpose of this clinical and anatomical study is to describe several novel biliary tract variations and to outline their practical importance for liver resections and transplantations.
  
  
  METHODS
  Over the previous 10 years, the anatomic variations of the bile ducts were examined during 600 intraoperative cholangiographies, 104 segmentectomies and 54 hemihepatectomies in patients with liver diseases. The intraoperative anatomies of the right and left hepatic ducts and the common hepatic duct confluence were analyzed.
  
  
  RESULTS
  Twenty-two variations occurred in 59.5% of the patients. Six variations were described for the first time: an accessory right hepatic duct in which a cystic duct drained; a tetrafurcation from the right anterior hepatic duct, right posterior hepatic duct and bile ducts for Segments 2 and 3 with aberrant bile drainage from Segment 4 into the bile duct for Segment 8; an aberrant bile drainage from Segments 6 and 7 into the common hepatic duct; an accessory bile duct for Segment 6 that drained into the bile duct for Segment 3; a tetrafurcation from the right anterior hepatic duct and the bile ducts for Segments 6, 3 and 2 with bile from Segment 7 draining into the bile duct for Segment 2; and an accessory bile duct for the left hemiliver that drained bile from the Type 4 small accessory hepatic lobe (according to Caygill & Gatenby) into the common hepatic duct.
  
  
  CONCLUSIONS
  These newly described biliary tract variations should be recognized by liver surgeons to avoid unwanted postoperative complications.
authors.affiliation: Department of Surgery, Naval Hospital of Varna, Varna, Bulgaria.
authors.forename: Daniel V
authors.initials: DV
authors.lastname: Kostov
authors.affiliation: Division of Surgery, Marko Markov Interregional Dispensary and Hospital of Oncological Diseases of Varna, Varna, Bulgaria.
authors.forename: Georgi L
authors.initials: GL
authors.lastname: Kobakov
keywords: Bile ducts; Biliary tract variations; Cholangiography; Hepatectomy; Liver segments