1. Department of Spine Surgery, Affiliated Hospital of Chengde Medical University, Shuangqiao District, Chengde, Hebei Province, China
2. Department of Orthopedic, The Affiliated Hospital of Qingdao University, Shinan District, Qingdao, Shandong Province, China
3. Department of Radiotherapy, The Third Affiliated Hospital of Kunming Medical University, Chenggong District, Kunming, Yunnan Province, China
4. School of Public Health, Jilin University, Chaoyang District, Changchun, Jilin Province, China