1. Department of Neurosurgery, Duke University School of Medicine, Durham, North Carolina, USA.
2. Kentucky Spinal Cord Injury Research Center, Louisville, Kentucky, USA.
3. Department of Neurosurgery, Houston Methodist Hospital, Houston TX, USA.
4. The Miami Project to Cure Paralysis, University of Miami, Miami, Florida, USA.
5. Department of Neurosurgery, The Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
6. University of Maryland School of Medicine, Baltimore, Maryland, USA.
7. Department of Neurosurgery, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
8. Department of Orthopedics, Miami Valley Hospital, Centerville, Ohio, USA.
9. Division of Neurosurgery and Spine Program, Department of Surgery, University of Toronto, Toronto, Ontario, Canada.
10. Division of Neurosurgery, Walter Reed National Military Medical Center, Bethesda, Maryland, USA.
11. Department of Neurosurgery, Massachusetts General Hospital, Boston, Massachusetts, USA.
12. Harvard Medical School, Boston, Massachusetts, USA.