1 Spine Truth Studying Group, Department of Orthopaedics, Baoji Municipal Central Hospital, Baoji, Shaanxi Province, China.
2 Spine Truth Studying Group, Department of Orthopedics, Ankang Hospital of Traditional Chinese Medicine, Shaanxi Province, China.
3 Spine Truth Studying Group, Department of Orthopedics, Chinese PLA No. 451 Hospital, Xi'an, Shaanxi Province, China.
4 Spine Truth Studying Group, Department of Orthopaedics, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province, China; Department of Orthopaedics, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi Province, China. Electronic address: hqwang@fmmu.edu.cn.