1. Department of Gastroenterological and Transplant Surgery, Graduate School of Biomedical and Health Sciences, Hiroshima University , Hiroshima , Japan
2. Department of Gastrointestinal Surgery and Surgical Oncology, Ehime University Graduate School of Medicine , Ehime , Japan
3. Department of Surgery, Hiroshima City North Medical Centre Asa Citizens Hospital , Hiroshima , Japan
4. Department of Gastroenterological Surgery, Hiroshima Prefectural Hospital , Hiroshima , Japan
5. Department of Surgery, Onomichi General Hospital , Onomichi , Japan
6. Department of Surgery, Chugoku Rosai Hospital , Kure , Japan
7. Department of Surgery, National Hospital Organization Higashihiroshima Medical Centre , Higashihiroshima , Japan
8. Department of Surgery, Hiroshima City Hiroshima Citizens Hospital , Hiroshima , Japan
9. School of Medicine, Center for Medical Education, Hiroshima University, Hiroshima, Japan