1. Department of Surgery Toho University Ohashi Medical Center Tokyo Japan
2. Department of Gastroenterological and Pediatric Surgery Oita University Faculty of Medicine Oita Japan
3. Biostatistics Center Kurume University Fukuoka Japan
4. Department of Gastroenterological Surgery Yokohama City University Graduate School of Medicine Kanagawa Japan
5. Department of Pediatric Surgery and Transplantation Kumamoto University Graduate School of Medical Sciences Kumamoto Japan
6. Minimally Invasive Surgery Center Yotsuya Medical Cube Tokyo Japan
7. Department of Surgery Fujinomiya City General Hospital Shizuoka Japan
8. Department of Gastrointestinal and Hepato‐Biliary‐Pancreatic Surgery Faculty of Medicine University of Tsukuba Ibaraki Japan
9. Department of Surgery 1 School of Medicine University of Occupational and Environmental Health Fukuoka Japan
10. Department of Digestive Surgery Kawasaki Medical School Okayama Japan
11. Department of General, Pediatric and Hepatobiliary‐Pancreatic Surgery Kitasato University School of Medicine Kanagawa Japan
12. Hepato‐Biliary‐Pancreatic Surgery Division Department of Gastroenterological Surgery Toranomon Hospital Tokyo Japan
13. Department of Hemodialysis and Surgery International University of Health and Welfare Ichikawa Hospital Chiba Japan
14. Department of Surgery Institute of Gastroenterology Tokyo Women's Medical University Tokyo Japan
15. Department of Surgery Teikyo University School of Medicine Tokyo Japan
16. Department of Surgery Keio University School of Medicine Tokyo Japan
17. Department of Gastrointestinal and Pediatric Surgery Tokyo Medical University Tokyo Japan
18. Department of Surgery Tsudanuma Central General Hospital Chiba Japan
19. Department of Surgery Tajimi City Hospital Gifu Japan
20. Department of Surgery Japanese Red Cross Nagoya Daini Hospital Aichi Japan
21. Department of Surgery Tohoku Rosai Hospital Miyagi Japan
22. Division of Gastroenterological, General and Transplant Surgery Department of Surgery Jicji Medical University Tochigi Japan
23. Department of Surgery Nakagami Hospital Okinawa Japan
24. Department of Gastroenterological Surgery Fujita Health University Bantane Hospital Aichi Japan
25. Department of Surgery Kansai Rosai Hospital Osaka Japan
26. Department of Gastrointestinal and Hepato‐Biliary‐Pancreatic Surgery Nippon Medical School Tokyo Japan
27. Department of Surgery Saitama Medical Center Jichi Medical University Saitama Japan
28. Department of Surgery The Jikei University School of Medicine Tokyo Japan
29. Department of Gastroenterological Surgery Shizuoka General Hospital Shizuoka Japan
30. Department of Surgery Shimada Municipal Hospital Shizuoka Japan
31. Department of Surgery and Oncology Graduate School of Medical Sciences Kyushu University Fukuoka Japan
32. Department of Hepato‐Biliary‐Pancreatic Surgery Sakai City Medical Center Osaka Japan
33. Department of Gastroenterological Surgery Osaka Police Hospital Osaka Japan
34. Department of Hepato‐Biliary‐Pancreatic Surgery Juntendo University School of Medicine Tokyo Japan
35. Department of Gastroenterological Surgery Ibaraki Seinan Medical Center Hospital Ibaraki Japan
36. Department of Surgery The Jikei University Kashiwa Hospital Chiba Japan
37. Department of Surgery Obihiro Kosei Hospital Hokkaido Japan
38. Department of Digestive Surgery KKR Tachikawa Hospital Tokyo Japan
39. Department of Gastroenterological Surgery Saga‐ken Medical Center Koseikan Saga Japan
40. Department of Surgery National Hospital Organization Tokyo Medical Center Tokyo Japan
41. Department of Hepato‐Biliary‐Pancreatic Surgery Tokyo Metropolitan Komagome Hospital Tokyo Japan
42. Department of Surgery Tohoku University School of Medicine Miyagi Japan
43. Department of Gastroenterological Surgery Nippon Medical School Chibahokusoh Hospital Chiba Japan
44. Department of Gastroenterological Surgery Kyoto Prefectural University of Medicine Kyoto Japan
45. Department of Surgery Sainokuni Higashiomiya Medical Center Saitama Japan