1. Department of Spine Surgery, Section II, Center for Orthopedic Surgery, The Third Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong 510610, P.R. China
2. Division of Orthopedics and Traumatology, Department of Orthopedics, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
3. Department of Orthopedics, Orthopaedic Hospital of Guangdong Province, Guangzhou, Guangdong 510610, P.R. China
4. Department of Orthopedics, Linzhi People's Hospital, Linzhi, Tibet 860000, P.R. China