1. Neurological Surgery and the Miami Project to Cure Paralysis, University of Miami, Miami, Florida, USA.
2. Department of Neurosurgery, Duke University, Durham, North Carolina, USA.
3. Massachusetts General Neurosurgery, Harvard University, Boston, Massachusetts, USA.
4. Department of Neurosurgery, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
5. Division of Neurosurgery, Walter Reed National Military Medical Center, Bethesda, Maryland, USA.
6. Division of Neurosurgery and Spine Program, Department of Surgery, University of Toronto, Toronto, Ontario, Canada.