title: Absence of bifurcation of the portal vein.
abstract: BACKGROUND
  Absence of the horizontal segment of the left portal vein (PV) or absence of bifurcation of the portal vein (ABPV) is extremely rare anomaly. The aim of this study was to study the extra-hepatic PV demonstrating the importance of its careful assessment for the purpose of split-liver transplantation.
  
  
  METHODS
  Human cadaver livers (n = 60) were obtained from routine autopsies. The cutting plane of the liver consisted of a longitudinal section made immediately on the left of the supra-hepatic inferior vena cava through the gallbladder bed preserving the arterial, portal and biliary branches in order to obtain two viable grafts (right lobe-segments V, VI, VII, and VIII and left lobe-segments II, III, and IV) as defined by the main portal scissure. The PV was dissected out and recorded for application of the liver splitting.
  
  
  RESULTS
  The PV trunk has been divided into right and left branch in 50 (83.3%) cases. A trifurcation of the PV was found in 9 (15.2%) cases, 3 (5%) was a right anterior segmental PV arising from the left PV and 6 (10%) a right posterior segmental PV arising from the main PV. ABPV occurred in 1 (1.6%) case.
  
  
  CONCLUSIONS
  Absence of bifurcation of the portal vein is a rare anatomic variation, the surgeon must be cautious and aware of the existence of this exceptional PV anomaly either pre or intra-operatively for the purpose of hepatectomies or even split-liver transplantation.
authors.affiliation: Department of Gastroenterology, Liver and Transplantation Surgery Unit, University of São Paulo School of Medicine, São Paulo, Brazil. eleazarchaib@yahoo.co.uk
authors.forename: Eleazar
authors.initials: E
authors.lastname: Chaib
mesh_terms: D006801:Humans; D016031:Liver Transplantation; D011169:Portal Vein / Q000033:anatomy & histology*; D012016:Reference Values
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