1. Department of Colorectal and Anus Surgery, Shanxi Provincial People's Hospital, Taiyuan, Shanxi 030001, P.R. China
2. Department of Gastroenterology, Jinhua People's Hospital, Jinhua, Zhejiang 321000, P.R. China
3. Department of General Surgery, Jinhua People's Hospital, Jinhua, Zhejiang 321000, P.R. China