1. Second Department of Surgery Wakayama Medical University Wakayama Japan
2. Department of Surgery Shiga University of Medical Science Otsu Japan
3. Department of Surgery Kansai Medical University Hirakata Hospital Hirakata Japan
4. Department of General and Gastroenterological Surgery Osaka Medical College Takatsuki Japan
5. Department of Hepato‐Biliary‐Pancreatic Surgery Osaka City University Graduate School of Medicine Osaka City Japan
6. Department of Gastroenterological Surgery Graduate School of Medicine Osaka University Suita Japan
7. Division of Digestive Surgery Department of Surgery Kyoto Prefectural University of Medicine Kyoto Japan
8. Department of Surgery Nara Medical University Kashihara Japan