1. Duke University, School of Medicine, Durham, North Carolina, USA.
2. Campbell University School of Osteopathic Medicine, Lillington, North Carolina, USA.
3. Kentucky Spinal Cord Injury Research Center, Louisville, Kentucky, USA.
4. Department of Neurosurgery, School of Medicine, University of Louisville, Louisville, Kentucky, USA.
5. Thomas Jefferson University Hospital, Philadelphia, Pennsylvania, USA.
6. Neuroscience Institute. The Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
7. Department of Orthopedic Surgery, Premier Health, Centerville Ohio, USA.
8. Department of Neurosurgery, Duke University, Durham, North Carolina, USA.
9. Division of Neurosurgery and Spine Program, Department of Surgery, University of Toronto, Toronto, Ontario, Canada.
10. Department of Neurosurgery, University of Maryland School of Medicine, Maryland, USA.
11. Division of Neurosurgery, Walter Reed National Military Medical Center, Bethesda, Maryland, USA.
12. Neurological Surgery and The Miami Project to Cure Paralysis, University of Miami, Miami, Florida, USA.