1. Department of Minimally Invasive Spine Surgery, Tianjin Hospital, Tianjin 300211, P.R. China
2. P.R. ChinaDepartment of General Practice, Xiamen Branch, Zhongshan Hospital, Fudan University, Xiamen, Fujian 361015, P.R. China
3. Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China