1. Department of Gastroenterological Surgery; Saitama Medical University International Medical Center; Hidaka Japan
2. Community Health Science Center; Saitama Medical University; Moroyama Japan
3. Department of General and Gastroenterological Surgery; Osaka Medical College; Takatsuki Japan
4. Department of Colorectal Surgery; Fujita Health University; Toyoake Japan
5. Department of Surgery; Iwate Medical University; Morioka Japan
6. Department of Surgery; National Hospital Organization Yokohama Medical Center; Yokohama Japan
7. Department of Surgery; Yokohama Shin-Midori General Hospital; Yokohama Japan
8. Department of Surgery; Kitasato University Hospital; Sagamihara Japan
9. Department of Surgery; Tokyo Medical and Dental University Hospital; Tokyo Japan