1. Department of Hepatobiliary Surgery, First Affiliated Hospital Medical College of Xi'an Jiaotong University, Xi'an, Shaanxi, China
2. Department of Thoracic Surgery, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
3. Department of General Surgery, First Affiliated Hospital Medical College of Xi'an Jiaotong University, Xi'an, Shaanxi, China