1. Department of Surgery Kyoto University Graduate School of Medicine Kyoto Japan
2. Department of Healthcare Quality Assessment Tokyo University Graduate School of Medicine Tokyo Japan
3. Project Management Subcommittee The Japanese Society of Gastroenterological Surgery Tokyo Japan
4. The Japanese Society of Gastroenterological Surgery Tokyo Japan
5. Database Committee The Japanese Society of Gastroenterological Surgery Tokyo Japan
6. Department of Surgery Osaka Red Cross Hospital Osaka Japan