1. Department of General Surgery, The Second Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, P.R. China
2. Department of General Surgery, The Fourth Affiliated Hospital of Nantong University, Yancheng, Jiangsu 224006, P.R. China
3. Department of Gastroenterology, Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, P.R. China
4. Medical College of Nantong University, Nantong, Jiangsu 226001, P.R. China