1. Department of Digestive and General Surgery Graduate School of Medicine University of the Ryukyus Okinawa Japan
2. Department of Surgery Nagasaki University Graduate School of Biomedical Sciences Nagasaki Japan
3. Department of Surgery Institute of Gastroenterology Tokyo Women's Medical University Tokyo Japan
4. Second Department of Surgery Wakayama Medical University Wakayama Japan
5. Department of Hepato‐Biliary‐Pancreatic and Breast Surgery Ehime University Graduate School of Medicine Toon Japan