1. Department of Osteology, The Lanzhou University Second Hospital, Lanzhou, Gansu 730030, P.R. China
2. Department of Osteology, The First Hospital of Lanzhou University, Lanzhou, Gansu 730030, P.R. China
3. Department of General Surgery, The First Hospital of Lanzhou University, Lanzhou, Gansu 730030, P.R. China