1. Department of Colorectal Anal Surgery, Zigong Fourth People’s Hospital, Zigong, Sichuan Province, China
2. Department of Gastrointestinal Oncology, The First Affiliated Hospital of Hainan Medical University, Haikou, Hainan Province, China
3. Department of General Surgery, Sichuan Mianyang 404 Hospital, Mianyang, Sichuan Province, China
4. Division of Gastrointestinal Surgery, Department of General Surgery, West China Hospital, Sichuan Province, China.