1. Department of General Surgery, Jinling Clinical Medical College, The Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210002, P.R. China
2. Department of General Surgery, The Affiliated Jiangyin Hospital of Southeast University Medical College, Jiangyin, Jiangsu 210002, P.R. China
3. Department of Gastrointestinal Surgery, People's Hospital of Tongling City, Tongling, Anhui 244005, P.R. China