The main hepatic anatomic variations for the purpose of split-liver transplantation.

BACKGROUND/AIMS: Variant hepatic anatomy must be recognized and appropriately managed during split-liver transplantation to ensure complete vascular and biliary supply to both grafts. The aim of this study was to demonstrate the importance of an assessment of the hepatic anatomical structures for the purpose of split-liver transplantation.

MATERIAL AND METHODS: Human cadaveric livers (n = 60) were obtained during routine autopsies. The cadavers and the livers had to comply with the following requirements: (1) minimum age 18 years, (2) no liver pathology expected from medical history, and (3) no liver pathology noted at autopsy. Resections were carried out en bloc with liver, celiac trunk, left gastric artery, lesser omentum, superior mesenteric artery, and head of the pancreas. The main anatomical structures of the liver as hepatic artery, portal vein, biliary tree, and hepatic veins were dissected and correlated hepatic segments for the application of liver splitting.

RESULTS: The right the median, and the left hepatic veins were unique, with in 59 (98.3%), 53 (88.3%) and 46 (76.3%) cases, respectively. The portal vein trunk divided into right and left branches in 59 (98.3%) cases. A median branch appeared in 9 (15.2%) cases and no bifurcation of the portal vein occurred in 1 (1.6%) case. The right and left hepatic ducts were multiple in 47 (78.3%) and 57 (95%) cases, respectively, however, the median, hepatic duct was unique in 16 (26.6%) cases. Examining the intrahepatic distribution of the right hepatic duct, we found 4 branches in 28 (59%) cases (segments V, VI, VII, and VIII) 2 branches in 11 (23%) cases, (segments V and VI) and 2 branches in 8 (17%) cases (segments VII and VIII). Fifty-seven cadavers had multiple left hepatic ducts. The intrahepatic dissection showed that the distribution of the major branches were toward hepatic segments II and III. Three separate branches of the left hepatic duct were found in 11 (19%) cases (segments II, III, and IV). Two intrahepatic ducts coming from hepatic segments V and VI drained separately into the left intrahepatic biliary tree in 1 (2%) case. The arterial supply of the liver was by right and left hepatic artery with only 9 (15%) cases there being median hepatic artery. The right hepatic artery, coming from the superior mesenteric artery, was present in 15 (25%) cases and a left hepatic artery originating from the left gastric artery in only 2 (3.3%) cases. The left hepatic artery had 2 exceptional origins, in 1 (1.6%) case coming directly from the abdominal aorta and in the other from the superior mesenteric artery. The right and left hepatic artery was accessory, in 11 (18.3%) and 2 (3.3%) cases, respectively. The right hepatic artery was dominant in 4 (6.6%) cases. The median hepatic artery was directed to segment IV in 6 (10%) cases and to segment II and III in 3 (4.9%) cases.

CONCLUSION: The study showed that the technique of controlled liver splitting for transplantation in 2 recipients is an acceptable method to increase the number of liver allografts. The anatomical and technical details of the splitting procedure are critical for the success of this technique. Good graft function and avoidance of complications depend on each graft having an intact arterial and portal blood supply as well as biliary and venous drainage from all retained liver segments. The absence of a bifurcation of the portal vein is a rare anomaly and would certainly contraindicate a partition.