1. Department of Surgery and Oncology, Graduate School of Medical Sciences, Kyushu University , Fukuoka , Japan
2. Department of Inflammatory Bowel Disease Surgery, Hyogo College of Medicine , Nishinomiya , Japan
3. Department of Surgery, Fukuoka University Chikushi Hospital , Chikushino , Japan
4. Department of Coloproctology, Tokyo Yamate Medical Centre , Tokyo , Japan
5. Department of Gastroenterological Surgery, Graduate School of Medicine, Osaka University , Osaka , Japan
6. Department of Surgery, Graduate School of Medicine, Osaka City University , Osaka , Japan
7. Department of Surgery, Graduate School of Medicine, Tohoku University , Sendai , Japan
8. Department of Surgery, Keio University , Tokyo , Japan
9. Department of Surgery, Coloproctology Centre, Takano Hospital , Kumamoto , Japan
10. Department of Infectious Diseases, Hiroshima University Hospital , Hiroshima , Japan
11. Department of Endoscopy, Hiroshima University Hospital , Hiroshima , Japan
12. Department of Gastrointestinal and Paediatric Surgery, Institute of Life Sciences, Graduate School of Medicine, Mie University , Tsu , Japan
13. Department of Surgery, Toho University Sakura Medical Centre , Chiba , Japan
14. Department of Surgery, National Defence Medical College , Tokorozawa , Japan
15. Advanced Surgery Centre, Sapporo Higashi Tokushukai Hospital , Sapporo , Japan
16. Department of Surgery, Division of Inflammatory Bowel Disease Surgery, Tokyo Women’s Medical University , Tokyo , Japan
17. Inflammatory Bowel Disease Centre, Yokohama City University Medical Centre , Yokohama , Japan
18. Department of Surgery, Kyoto University Hospital , Kyoto , Japan
19. Department of Gastrointestinal Surgery, Tokyo Medical and Dental University , Tokyo , Japan
20. Department of Colorectal Surgery, Tohoku Rosai Hospital , Sendai , Japan
21. Department of Surgery, Nara Medical University , Kashihara , Japan
22. Department of Surgery, School of Medicine, Fujita Health University , Toyoake , Japan
23. Department of Gastroenterological Surgery, Osaka City General Hospital , Osaka , Japan
24. Kurume Coloproctology Centre , Kurume , Japan
25. Division of Digestive and General Surgery, Graduate School of Medical and Dental Sciences, Niigata University , Niigata , Japan
26. Inflammatory Bowel Disease Centre, Yokkaichi Hazu Medical Centre , Yokkaichi , Japan
27. Centre for Gastroenterology, Department of Surgery, Urasoe General Hospital , Urasoe , Japan
28. Department of Surgery, School of Medicine, Teikyo University , Tokyo , Japan
29. Department of General and Gastroenterological Surgery, Osaka Medical College , Takatsuki , Japan
30. Department of Surgery, Kyorin University , Tokyo , Japan
31. Department of Surgery, Kurume University Hospital , Kurume , Japan
32. Department of Surgery, Tokyo Medical University Hospital , Tokyo , Japan
33. Department of Gastroenterological Surgery, Nagoya University Hospital , Nagoya , Japan
34. Department of Digestive Surgery, Nippon Medical School , Tokyo , Japan
35. Department of Coloproctological Surgery, Japanese Red Cross Medical Centre , Tokyo , Japan
36. Department of Surgical Oncology, University of Tokyo , Tokyo , Japan
37. Department of Pathology, Niigata University , Niigata , Japan
38. Tokyo Medical and Dental University , Tokyo , Japan