1. Department of Surgery Shiga University of Medical Science Otsu Japan
2. Department of Surgery Meiwa Hospital Nishinomiya Japan
3. Hepato‐Biliary‐Pancreatic Surgery Division Department of Surgery Graduate School of Medicine The University of Tokyo Tokyo Japan
4. Department of Gastroenterological Surgery Graduate School of Medicine Osaka University Osaka Japan
5. Department of Hepato‐Biliary‐Pancreatic Surgery Tokyo Medical and Dental University Tokyo Japan
6. Department of Surgery Institute of Gastroenterology Tokyo Women’s Medical University Tokyo Japan
7. Second Department of Surgery Wakayama Medical University Wakayama Japan