1. Department of Gastrointestinal and Hepato‐Biliary‐Pancreatic Surgery Faculty of Medicine University of Tsukuba Tsukuba Japan
2. Department of Gastroenterological and Pediatric Surgery Faculty of Medicine Oita University 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 Surgery Toho University Ohashi Medical Center Tokyo Japan
9. Department of Surgery and Oncology Graduate School of Medical Sciences Kyushu University 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 Sagamihara 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 Gastroenterological Surgery New Tokyo Hospital Matsudo 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 Sainokuni Higashiomiya Medical Center Saitama 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. Department of Surgery Division of Gastroenterological, General and Transplant Surgery Jichi 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 Suregery Kansai Rosai Hospital Amagasaki Japan
26. Department of Gastrointestinal and Hepato‐Biliary‐Pancreatic Surgery Nippon Medical School Tokyo Japan
27. Department of Surgery Saitama Medical CenterJichi Medical University Saitama Japan
28. Department of Surgery Institute of Gastroenterology Tokyo Women's Medical University Tokyo Japan
29. Department of Surgery The Jikei University School of Medicine Tokyo Japan
30. Department of Hepato‐Biliary‐Pancreatic Surgery Kobe University Graduate School of Medicine Kobe Japan
31. Department of Surgery Kobe Medical Center Kobe Japan
32. Division of Gastrointestinal Surgery Department of Surgery Kobe University Graduate School of Medicine Kobe Japan