1. Department of Spine Surgery, The Central Hospital of Yongzhou, Yongzhou, Hunan 425000, P.R. China
2. Department of Orthopedic Surgery, The Sixth Medical Centre of PLA General Hospital, Beijing 100053, P.R. China
3. Department of Orthopedic Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China