1. Department of General Surgery I, Zhangye Second People's Hospital, Zhangye, Gansu 734000, P.R. China
2. Department of General Surgery I, Zhangye Second People's Hospital, Zhangye, Gansu 734000, P.R. China
3. Department of Hepatobiliary Surgery, Xijing Hospital of Air Force Military Medical University, Xi'an, Shaanxi 710000, P.R. China
4. Department of Urology, Hexi University Affiliated Zhangye People's Hospital, Zhangye, Gansu 734000, P.R. China