Xiangbai Wu1, Yayuan Wei2, DongDong Wang1. 1. Department of Colorectal Surgery, China Three Gorges University Colorectal Disease Research Institute, The Second Hospital of Yichang, No 21 XiLing First Street, Yichang City, 443000, China. 2. Department of Colorectal Surgery, China Three Gorges University Colorectal Disease Research Institute, The Second Hospital of Yichang, No 21 XiLing First Street, Yichang City, 443000, China. wdd_yc@163.com.