1. Department of Gastrointestinal Surgery, Department of General Surgery, Guangdong Provincial People’s Hospital, Guangdong Academy of Medical Sciences, Southern Medical University , Guangzhou, Guangdong, P. R. China
2. Shantou University Medical College , Shantou, Guangdong, P. R. China
3. Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan, Hubei, P. R. China
4. Department of General Surgery, Zhujiang Hospital of Southern Medical University , Guangzhou, Guangdong, P. R. China
5. Department of Gastrointestinal Surgery, Huizhou Municipal Central Hospital , Huizhou, Guangdong, P. R. China
6. Department of Gastrointestinal Surgery, Guangdong Second Provincial General Hospital , Guangzhou, Guangdong, P. R. China
7. Department of Gastrointestinal Surgery, The Second Xiangya Hospital of Central South University , Changsha, Hunan, P. R. China
8. Department of Surgical Treatment of Gastrointestinal Hernia and Fistula, The People’s Hospital of Guangxi Zhuang Autonomous Region, Guangxi Academy of Medical Sciences , Nanning, Guangxi, P. R. China
9. Department of General Surgery, The Third Affiliated Hospital of Southern Medical University , Guangzhou, Guangdong, P. R. China
10. Department of Gastrointestinal Surgery, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangdong Provincial Hospital of Traditional Chinese Medicine , Guangzhou, Guangdong, P. R. China
11. Department of Gastrointestinal Surgery, Guangzhou First People’s Hospital , Guangzhou, Guangdong, P. R. China
12. Department of Gastrointestinal Surgery, Meizhou People’s Hospital , Meizhou, Guangdong, P. R. China
13. lnformation and Statistics Center, Guangdong Provincial People’s Hospital, Guangdong Academy of Medical Sciences, Southern Medical University , Guangzhou, Guangdong, P. R. China