Surgical implications of the confluence patterns of the left intrahepatic bile ducts in right hepatectomy for perihilar cholangiocarcinoma.

BACKGROUND: Although the most important goal in surgery for perihilar cholangiocarcinoma (PHC) is to achieve tumor-free proximal ductal margins, little is known about the implications of confluence patterns of the left intrahepatic bile ducts for the proximal ductal margin status in right hepatectomy (RH) for PHC. METHODS: Of 203 patients who underwent surgical resection for PHC with curative intent, confluence patterns of the left intrahepatic bile duct were evaluated in 94 consecutive patients who underwent RH, and they were classified into the following two types: normal type: the bile duct of segment 4 (B4) drained into the common trunk of the bile ducts of segment 2 (B2) and segment 3 (B3) at the right side of the umbilical portion of the left portal vein to form the left hepatic duct; and hepatic confluence type: B2 entered the common trunk of B3 and B4 at the hepatic confluence or B4 entered the common trunk of B2 and B3 at the hepatic confluence. The proximal ductal margin status following RH was compared between the two types of confluence patterns. RESULTS: Of 94 consecutive patients, 69 (73%) were the normal type, and 25 (27%) were the hepatic confluence type. There were no significant differences in patients' characteristics, surgical characteristics, surgical outcomes, and histopathological features between the two groups. However, in patients with Bismuth-Corlette type II and IIIa PHC, the achievement rates of negative proximal ductal margins at the first dividing line were significantly higher in the hepatic confluence type group than in the normal type group (16/16 [100%] vs 34/52 [65%], respectively; P = .007). CONCLUSIONS: Confluence patterns of the left intrahepatic bile ducts might affect proximal ductal margin status in RH for PHC.