1. Department of Orthopedics, Beijing Friendship Hospital, Capital Medical University, No. 95, Yong An Rd, Beijing 100050, China
2. Department of Spinal Surgery, Peking University People’s Hospital, 11th Xizhimen South Ave., Beijing 100044, China
3. Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing 100083, China