Biliary Merging Patterns of the Caudate Lobe: A Review Report

Concerning the previous anatomical knowledge and requirements of current hepato-pancreato-biliary practice it was our aim to enhance the anatomy knowledge of the caudate lobe biliary drainage. Using the injection-corrosion method we made 27 acrylic porto-biliary casts of proper quality from 30 post-mortem, adult human liver specimens. During the observation under a magnifying glass a portal vascular segmentation was determined along with intrahepatic merging patterns of biliary ducts. In segment 1, the biliary drainage appeared as a confluence of segmental ducts from two distinct portions, left and right. According to their merging patterns we found a separate confluence of both portions in 16/27 casts, their common confluence in 7/27 casts, and a combined confluence in 4/27 casts. The total number of ducts, based on their ending manner of confluence, was 1 in 11 cases, 2 in 9 cases, and 3 in 4 cases. The confluence of both portion ducts was most frequently into the same collecting duct (11/27), then into different collecting ducts (9/27), and rarely it was a combined confluence (3/27), on contrary to the confluence only from one portion, left or right (4/27). Drainage into ducts of different order was also observed: the first (left and right hepatic duct), the second (posterior and anterior right sectoral ducts, left lateral sectoral duct), and the third order (segment 2 duct). These anatomical data addressing the key elements in the liver hilum are important when performing caudate lobectomies or when performing it in combination with major liver resection.