1. Department of Gastroenterological Surgery, Graduate School of Social and Cultural Sciences; Kumamoto University; Kumamoto Japan
2. Hepatobiliary and Pancreatic Surgery Division; National Cancer Center Hospital; Tokyo Japan
3. Hepato-Biliary-Pancreatic Surgery Division, Department of Surgery, Graduate School of Medicine; University of Tokyo; Tokyo Japan
4. Department of Surgery; Tokyo Metropolitan Komagome Hospital; Tokyo Japan
5. Department of Gastroenterological Surgery; Yokohama City University Graduate School of Medicine; Yokohama Japan
6. Department of Surgery, Institute of Gastroenterology; Tokyo Women's Medical University; 8-1 Kawadacho, Shinjyukuku Tokyo 162-8666 Japan
7. Department of Surgery; Iwate Medical University School of Medicine; Iwate Japan
8. Department of General Surgery; Chiba University Graduate School of Medicine; Chiba Japan
9. Department of Surgery, Graduate School of Medicine; Kyoto University; Kyoto Japan
10. Second Department of Surgery; Wakayama Medical University, School of Medicine; Wakayama Japan
11. Department of Gastroenterological Surgery, Graduate School of Medicine; Kanazawa University; Kanazawa Japan
12. Medical Quality Management Center, Graduate School of Social and Cultural Sciences; Kumamoto University; Kumamoto Japan
13. Japanese Society of Hepato-Biliary-Pancreatic Surgery, Department of Surgery; Teikyo University School of Medicine; Tokyo Japan