Right/left symmetry of the intrahepatic distribution and terminology of the hepatic artery proper and the intrahepatic bile duct system: proposals to revise the Terminologia Anatomica

Right hepatic artery crossing the common hepatic artery: an unusual blood supply to the liver

To perform hepatic surgery a precise preoperative and intraoperative study of liver vascular supply is mandatory. Detecting vascular variations may have great importance on surgical strategy and outcome, and details of anatomy do not concern only academical knowledge but become deeply involved in practice. We present a case of unusual blood supply to the liver, the common hepatic artery was directed to the right liver and a right hepatic artery originating from the superior mesenteric artery was directed to the left liver. The right hepatic artery crossed the common hepatic artery in the proximal part of the hepatic pedicle, anterior to the portal vein. To our knowledge this type of anatomical variation has not been described before and it represents a rare finding that has to be kept in mind, especially in case of major hepatectomies and more demanding splitting liver procedures such as A.L.P.P.S., in situ split, ex situ split and living donor liver transplantation.

Bile duct confluence: anatomic variations and its classification

Accurate knowledge of the anatomy of the bile ducts is critical for successfully hepato-biliary surgery. We describe the anatomical variations of the confluence of the bile ducts, their branches patterns, frequency and classification. From 1996 to 2011, we have collected data of the bile duct confluence. 2,032 and 1,014 anatomical variations of right and left bile ducts, respectively, were reviewed and classified according to the branching pattern. The frequencies of each type of the right hepatic duct (RHD) were as follows: Type A1-1,247 (61.3%); Type A2-296 (14.5%); Type A3-272 (13.3%); Type A4-124 (6.1%); Type A5-21 (1%) and others-72 (3.5%) and, for the left hepatic duct (LHD) was as follows: Type B1-773 (76.2%); Type B2-153 (15%); Type B3-38 (3.7%); Type B4-9 (0.8%); Type B5-29 (2.8%) and others-12 (1.1%). Atypical branching patterns of both the right and left hepatic ducts were found in 14 and 8%, respectively. The two most common variations of the RHD were right anterior and posterior hepatic ducts join together to form the RHD and trifurcation where the RHD is absent and right anterior and posterior hepatic ducts join directly to the confluence with the LHD to form the common hepatic duct. The two most common variations in the LHD were segment IV drainage to the left and right hepatic ducts.