1. Department of Surgery Shiga University of Medical Science Shiga Japan
2. Department of General and Gastroenterological Surgery Osaka Medical College Osaka Japan
3. Second Department of Surgery Wakayama Medical University Wakayama Japan
4. Department of Gastroenterological Surgery Graduate School of Medicine Osaka University Osaka Japan
5. Department of Hepato‐Biliary‐Pancreatic Surgery Osaka City University Graduate School of Medicine Osaka Japan
6. Department of Surgery Nara Medical University Nara Japan
7. Department of Surgery Faculty of Medicine Kinki University Osaka Japan
8. Department of Surgery Kansai Medical University Osaka Japan