1. Department of Colorectal Surgery, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, Guangzhou, Guangdong, P. R. China
2. Department of Gastrointestinal Surgery, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, P. R. China
3. Department of General Surgery, Dongguan Kanghua Hospital, Dongguan, Guangdong, P. R. China
4. Department of Gastrointestinal Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, P. R. China
5. Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, P. R. China
6. Department of General Surgery, Beijing Friendship Hospital, Beijing, P. R. China
7. Department of Colorectal Surgery, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, P. R. China
8. Department of General Surgery, Peking University Third Hospital, Beijing, P. R. China
9. Department of Gastrointestinal Surgery, Daping Hospital, Third Military Medical University, Chongqing, P. R. China
10. Department of Gastrointestinal Surgery, Peking University People’s Hospital, Beijing, P. R. China
11. Department of General Surgery, Chongqing Three Gorges Center Hospital, Chongqing, P. R. China