1. Department of Surgery; Kansai Medical University; Hirakata Osaka Japan
2. Department of General Surgery; Chiba University Graduate School of Medicine; Chiba Japan
3. Department of Surgery; Tohoku University Graduate School of Medicine; Sendai Miyagi Japan
4. Second Department of Surgery; School of Medicine; Wakayama Medical University; Wakayama Japan
5. Department of Surgery and Science; Graduate School of Medicine and Pharmaceutical Sciences for Research; University of Toyama; Toyama Japan
6. Department of Surgery; Teikyo University School of Medicine; Tokyo Japan
7. Division of Gastroenterological Surgery; Chiba Cancer Center Hospital; Chiba Japan
8. Department of Surgery; Nara Medical University; Kashihara Nara Japan
9. Department of Surgery; Kindai University; Faculty of Medicine; Higashiosaka Osaka Japan
10. Department of Gastroenterological Surgery II; Hokkaido University Graduate School of Medicine; Sapporo Hokkaido Japan