1. Department of General Surgery, The Fourth Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230000, P.R. China
2. Department of Critical Care Medicine, Northern Jiangsu People's Hospital Affiliated to Yangzhou University, Yangzhou, Jiangsu 225001, P.R. China
3. Department of General Surgery, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230000, P.R. China
4. Department of Hepatobiliary and Pancreatic Surgery, Northern Jiangsu People's Hospital Affiliated to Yangzhou University, Yangzhou, Jiangsu 225001, P.R. China