1. Department of surgery Tohoku University Graduate School of Medicine Sendai Japan
2. Department of Surgery Seoul National University College of Medicine Seoul Korea
3. Department of Surgery Yonsei University College of Medicine Seoul Korea
4. Department of Surgery Iwate Medical University Morioka Japan
5. Department of Surgery CHA University Pocheon Korea
6. Department of Gastroenterological Surgery II Hokkaido University Faculty of Medicine Sapporo Japan
7. Department of Surgery Chonbuk National University Medical School Jeonju Korea
8. Institute of Gastroenterology Tokyo Women's Medical University Tokyo Japan