1. 8th Department of Orthopaedics, Foshan Hospital of Traditional Chinese Medicine, Foshan 528000, P. R. China
2. Key Laboratory of Polymer Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022, P. R. China
3. School of Applied Chemistry and Engineering, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, P. R. China
4. Department of Spine Surgery, China-Japan Union Hospital of Jilin University, N. 126 Xiantai Street, Changchun 130033, Jilin, P. R. China