1. Department of Gastroenterological Surgery; Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences; Okayama Japan
2. Center for Innovative Clinical Medicine; Okayama University Hospital; Okayama Japan
3. Department of Surgery; Hiroshima City Hiroshima Citizens Hospital; Hiroshima Japan
4. Department of Surgery; Fukuyama Medical Center; Fukuyama Japan
5. Department of Surgery; Mihara Red Cross Hospital; Mihara Japan
6. Department of Surgery; Kagawa Prefectural Center Hospital; Takamatsu Japan
7. Department of Surgery; Kagawa Rosai Hospital; Marugame Japan
8. Department of Surgery; Shikoku Cancer Center; Matsuyama Japan
9. Department of Surgery; Okayama Saiseikai General Hospital; Okayama Japan
10. Department of Surgery; Iwakuni Clinical Center; Iwakuni Japan
11. Minimally Invasive Therapy Center; Okayama University Hospital; Okayama Japan
12. Department of Surgery; Matsuda Hospital; Kurashiki Japan