1. Department of General Surgery, The First Affiliated Hospital, Jinan University, Guangzhou, Guangdong 510630, P.R. China
2. Department of General Surgery, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, Guangdong 510180, P.R. China
3. Department of General Surgery, Shenzhen Hospital, Southern Medical University, Shenzhen, Guangdong 518101, P.R. China