1. Department of Orthopedic Surgery, China Medical University Hospital, Taichung 404327, Taiwan
2. Spine Center, China Medical University Hospital, No. 2, Xueshi Rd., North Dist., Taichung 404327, Taiwan
3. Department of Orthopedic Surgery, China Medical University Beigang Hospital, Yunlin 651012, Taiwan
4. Graduate Institute of Precision Engineering, National Chung Hsing University, Taichung 402204, Taiwan