Anatomy of the hepatic hilar area: the plate system

Abstract

To surgically manage hilar bile duct carcinoma successfully, it is important to be familiar with the principal anatomical variations of the biliary and vascular components of the plate system in the hepatic hilar area, because all the variations in the bile ducts and vessels occur in the plate system. The plate system consists of bile ducts and blood vessels surrounded by a sheath. There are three plates in the hilar area: the hilar plate, the cystic plate, and the umbilical plate. The bile duct and blood vessel branches penetrate the plate system and form Glisson's capsule in all segments of the liver, except for the medial segment. The right hepatic duct is usually (in 53%-72% of individuals) formed by the union of the anterior segmental duct and the posterior segmental duct in the hilar area. However, three other variations have been found in which these segmental ducts do not form the right hepatic duct. Few anatomical variations have been identified in the left hepatic duct, but confusion arises because of the variations in the medial segment ducts (B4) which join the left hepatic duct at different sites. In 35.5% of individuals they join the hepatic duct in the vicinity of the hilar confluence (type I B4 anatomy), and in 64.5% of individuals they join the left hepatic duct some distance away from the confluence (type II B4 anatomy). Because B4 is very close to the hilar confluence in type I, hilar bile duct carcinoma can easily invade B4 and, for that reason, for curative resection of hilar bile duct carcinoma, resection of S4a (the inferior part of the medial segment) should be considered along with the resection of extrahepatic bile duct and caudate lobe. Variations in the portal vein and hepatic artery are found in 16%-26% and 31%-33% of individuals, respectively. Because a considerable number of anatomical variations in the bile ducts and vessels persist in the hilar area, and the reported proportions of the different variations vary, it is necessary to have a good knowledge of the plate system and the variations in the bile ducts and blood vessels in the hilar area to perform safe and curative surgery for hilar bile duct carcinoma.

Six Rare Biliary Tract Anatomic Variations: Implications for Liver Surgery

“…Intrahepatically, all of the bile ducts except for Sg4 are covered by Glisson's capsule [23]. Sg4 was often solitary and drained centrally into the LHD.…”

First results of radical and conditionally radical resections for Klatskin tumors

“…В настоящее время резекция 1-го сегмента является обязательной составляющей резекци-онных вмешательств при II-IV типах опухоли по классификации Bismuth-Corlette, что обо-сновано необходимостью удаления коллектора лимфогенного метастазирования опухоли по системе протоков воротной пластинки [11]. Резекция 1-го сегмента была выполнена у 44% из оперированных нами больных.…”

Spatial Anatomical Variation of Segmental Hepatic Vasculature and Bile Duct Assessed by Integrated 3D CT Images for Right Lateral Sector Graft Liver Transplantation

“…We defined the right lateral bile duct/artery which run dorsally and superiorly to RMPV as a 'north-turning' duct/artery and the bile duct/artery which run ventrally and inferiorly to the right portal vein and RMPV was defined as a 'south-turning' duct/artery 12) (Fig 6). In 49 patients with single RLD, 44 had the 'northturning' duct and 5 had the 'south-turning' duct.…”