1. From the Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, The Jikei University School of Medicine, Tokyo, Japan (Haruki, Furukawa, Taniai, Yanagaki, Igarashi, Tsunematsu, Shirai, Ikegami)
2. Division of Hepatobiliary and Pancreatic Surgery, Department of General Surgery, Graduate School of Medicine, Gunma University, Maebashi, Japan (Harimoto, Shirabe).