1. Department of Spine Surgery, The Affiliated Yuebei People's Hospital of Shantou University Medical College, Shaoguan, Guangdong 512025, P.R. China
2. Department of Orthopedics, Zhujiang Hospital, The Second School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong 510280, P.R. China
3. Department of Oral and Maxillofacial Surgery, Stomatological Hospital of Southern Medical University, Guangzhou, Guangdong 510250, P.R. China