1. Department of Orthopedic Surgery, Chang Gung Memorial Hospital, Keelung Branch, Bone and Joint Research Center, Chang Gung University, F7, No 222 Mai-King Road, Keelung 20401, Taiwan
2. Mayo Clinic Neuro-Informatics Laboratory, Mayo Clinic, Rochester, MN 55902, USA
3. Department of Neurological Surgery, Mayo Clinic, Rochester, MN 55902, USA