1. Department of Pancreatic Surgery, West China Hospital of Sichuan University, Chengdu 610041, Sichuan Province, China
2. Department of General Surgery, The First Affiliated Hospital of Xinxiang Medical College, Weihui 453100, Henan Province, China
3. Department of Gastrointestinal Surgery, West China Hospital of Sichuan University, Chengdu 610041, Sichuan Province, China
4. Department of Hepatobiliary Surgery, The People's Hospital of Deyang, Deyang 618000, Sichuan Province, China