1. Department of Spine Surgery, Baoji Central Hospital, Baoji, Shaanxi 721008, P.R. China
2. Department of Orthopaedics, Baoji Central Hospital, Baoji, Shaanxi 721008, P.R. China
3. Department of Rehabilitation and Pain, The Second Affiliated Hospital of Shaanxi University of Traditional Chinese Medicine, Xianyang, Shaanxi 712000, P.R. China
4. Department of Orthopaedics, The Third Hospital of Xi'an City, Xi'an, Shaanxi 710018, P.R. China