1. Department of Orthopedics, The Third Hospital of Shijiazhuang Hebei Province, Shijiazhuang, Hebei 050051, P.R. China
2. Department of Spinal Surgery, The Third Hospital of Hebei Medical University, Key Biomechanical Laboratory of Orthopedics, Shijiazhuang, Hebei 050051, P.R. China
3. Department of Orthopedics, The 251st Hospital of PLA, Zhangjiakou, Hebei 075000, P.R. China
4. Department of Orthopedics, Gaocheng People's Hospital, Shijiazhuang, Hebei 050000, P.R. China