1. Department of Orthopedic Trauma and Hand Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, P. R. China
2. Department of Orthopedics, The Affiliated Zhongshan Hospital of Dalian University, Dalian, Liaoning, P. R. China
3. Department of Spinal Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, P. R. China