1. Department of Digestive Surgery; Kawasaki Medical School; Kurashiki Japan
2. Department of Surgery and Oncology, Graduate School of Medical Sciences; Kyushu University; Fukuoka Japan
3. Department of Surgery; Iwate Medical University School of Medicine; Morioka Japan
4. Division of Hepato-Biliary-Pancreatic Surgery, Department of Surgery; Tohoku University Graduate School of Medicine; Sendai Japan
5. Department of Surgery; Kitasato University School of Medicine; Sagamihara Japan
6. Department of Surgery; Kansai Medical University; Hirakata Japan
7. Department of Surgery, Division of Hepato-Biliary-Pancreatic Surgery; Kobe University Graduate School of Medicine; Kobe Japan
8. Department of General Surgery, Graduate School of Medicine; Chiba University; Chiba Japan
9. Hepatobiliary and Pancreatic Surgery Division; National Cancer Center Hospital; Tokyo Japan
10. First Department of Surgery; Shinshu University School of Medicine; Matsumoto Japan
11. The Jikei University School of Medicine; Tokyo Japan
12. Department of Gastroenterological Surgery (Surgery II); Nagoya University Graduate School of Medicine; Nagoya Japan
13. Department of Hepatology and Pancreatology; Kawasaki Medical School; Kurashiki Japan
14. Department of Healthcare Quality Assessment, Graduate School of Medicine; The University of Tokyo; Tokyo Japan
15. Department of Gastroenterological Surgery, Graduate School of Life Sciences; Kumamoto University; Kumamoto Japan
16. Second Department of Surgery, School of Medicine; Wakayama Medical University; Wakayama Japan
17. Department of Surgery; Teikyo University School of Medicine; Tokyo Japan