1. The Rothman Institute at Thomas Jefferson University, Philadelphia, Pennsylvania;
2. The Swedish Neuroscience Institute;
3. University of Washington, Seattle, Washington;
4. University Medical Center, Utrecht, The Netherlands;
5. Medical University Innsbruck, Department of Orthopaedic Surgery, Innsbruck, Austria;
6. University of British Columbia, Vancouver, British Columbia;
7. University of Maryland School of Medicine, Baltimore, Maryland;
8. Catholic University, Curitiba, Brazil;
9. University of Toronto, Ontario, Canada;
10. Ganga Hospital, Coimbatore, India,
11. Centerfor Spinal Surgery and Neurotraumatology, BG Unfallklinik Frankfurt; and
12. Schön Klinik Nürnberg Fürth, Center for Spinal Surgery, Fürth, Germany