1. School of Medicine, Spine Center, University of California San Francisco, San Francisco, California, USA.
2. Department of Neurological Surgery, Spine Center, University of California San Francisco, San Francisco, California, USA.
3. Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital, San Francisco, California, USA.
4. Department of Orthopaedic Surgery, Spine Center, University of California San Francisco, San Francisco, California, USA.
5. Orthopedic Trauma Institute, Zuckerberg San Francisco General Hospital, San Francisco, California, USA.
6. Weill Institutes for Neurosciences, San Francisco, California, USA.
7. Department of Neurological Surgery, UCSF-Fresno, Fresno, California, USA.
8. Institute for Neurodegenerative Diseases, Spine Center, University of California San Francisco, San Francisco, California, USA.
9. San Francisco Veterans Affairs Healthcare System, San Francisco, California, USA.