Intrahepatic segmental bile duct patterns in hepatolithiasis: A comparative cholangiographic study between Taiwan and Japan

Background/Purpose. We analyzed confluence patterns of intrahepatic segmental bile ducts, seeking to relate hepatolithiasis to anatomic variation. The comparative study was completed patients with hepatolithiasis in Taiwan and Japan. Methods. Direct cholangiography was performed in 103 hepatolithiasis patients in Taiwan and 77 in Japan. Segmental ducts patterns were classified as type I, normal configuration; type II, "triad" confluence; type III, posterior segmental duct joining left hepatic duct; or type IV, distal confluence of the right posterior segmental duct. Results. Taiwanese patients had only calcium bilirubinate or black stones, and were mostly female. As overall analysis, types I, II, III, and IV were found in 61, 26, 13, and 3 patients, respectively. In Japanese, types I, II, III, and IV were found in 52, 10, 13, and 2, respectively. There was no difference between the two institutes. Since no patients in Taiwan had cholesterol calculi, Japanese patients were reanalyzed including only 58 patients with calcium bilirubinate or black stones. Differences in those populations remained insignificant. Conclusion. Anatomic variations in segmental ducts apparently do not contribute to pathogenesis of hepatolithiasis.