1. Department of Pancreatic Surgery, Sichuan University West China Hospital, Chengdu 610041, China
2. Department of Hepatobiliary Surgery, Southwest Hospital, Army Medical University, Chongqing 400038, China
3. Department of Hepatobiliary Surgery, First Affiliated Hospital of Kunming Medical University, Kunming 650032, China
4. Department of Hepatobiliary Surgery, Second Affiliated Hospital of Kunming Medical University, Kunming 650106, China
5. Department of Pancreatic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China