1. Department of Gastroenterological Surgery Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Okayama Japan
2. Center for Innovative Clinical Medicine Okayama University Hospital Okayama Japan
3. Department of Surgery Okayama Saiseikai General Hospital Okayama Japan
4. Department of Surgery Hiroshima Citizens Hospital Hiroshima Japan
5. Department of Surgery Kochi Health Sciences Center Kochi Japan
6. Department of Surgery Himeji Red Cross Hospital Himeji Japan
7. Department of Surgery National Hospital Organization Fukuyama Medical Center Fukuyama Japan
8. Department of Surgery Tottori Municipal Hospital Tottori Japan