1. Department of Gastrointestinal and Pancreatic Surgery, The First Affiliated Hospital of Sun Yat-Sen University, 58 2nd Zhongshan Road, Guangzhou, Guangdong 510080, China
2. Department of Surgery, Jinling Hospital, Medical School of Nanjing University, 305 East Zhongshan Road, Nanjing, Jiangsu 210002, China