1. Gastroenterological and Pediatric Surgery Oita University of Faculty of Medicine Yufu Oita Japan
2. Department of Healthcare Quality Assessment Graduate School of Medicine The University of Tokyo Tokyo Japan
3. Department of Surgery Kyorin University School of Medicine Tokyo Japan
4. First Department of Surgery Dokkyo Medical University Tochigi Japan
5. Department of Gastroenterological Surgery Toranomon Hospital Tokyo Japan
6. Department of Surgery Graduate School of Medicine Kyoto University Kyoto Japan
7. Department of Surgery NTT Medical Center Tokyo Japan
8. Department of Surgery Toho University Ohashi Medical Center Tokyo Japan
9. Department of Surgery Tokai University School of Medicine Kanagawa Japan
10. Department of Surgery Tokyo Dental College Ichikawa General Hospital Chiba Japan
11. Department of Surgery National Defense Medical College Saitama Japan
12. Division of Gastrointestinal Surgery Department of Surgery Kobe University Graduate School of Medicine Kobe Japan
13. Department of Surgery Keio University School of Medicine Tokyo Japan
14. Department of Surgery Kitasato University Kitasato Institute Hospital Tokyo Japan