1. Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania;
2. Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania;
3. Neurological Surgery, Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, Pennsylvania;
4. Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota;
5. Department of Neurosurgery, University of Utah, Salt Lake City, Utah;
6. Department of Neurosurgery, Columbia University Irving Medical Center, New York, New York;
7. Department of Neurological Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin;
8. Department of Neurosurgery, University of California, San Francisco, San Francisco, California;
9. Department of Neurosurgery, University of California, Los Angeles, Los Angeles, California;
10. Department of Neurological Surgery, University of Miami, Miami, Florida;
11. Atlanta Brain and Spine Care, Atlanta, Georgia;
12. Atlantic Neurosurgical Specialists, Morristown, New Jersey;
13. Department of Neurosurgery, Duke University, Durham, North Carolina;
14. Department of Neurological Surgery, Weill Cornell Medical Center, New York, New York;
15. Norton Leatherman Spine Center, Louisville, Kentucky;
16. Department of Neurosurgery, University of Virginia, Charlottesville, Virginia;
17. Department of Neurosurgery, Semmes Murphey Clinic, University of Tennessee, Memphis, Tennessee;
18. Department of Neurosurgery, Washington University School of Medicine in St. Louis, St. Louis, Missouri;
19. Neuroscience Institute, Carolina Neurosurgery & Spine Associates, Carolinas Healthcare System, Charlotte, North Carolina;
20. Geisinger Health, Danville, Pennsylvania;
21. Department of Neurosurgery, University of North Carolina, Chapel Hill, North Carolina;
22. Department of Neurological Surgery, Goodman Campbell Brain and Spine, Indianapolis, Indiana; and
23. Department of Neurosurgery, Barrow Neurological Institute, Phoenix, Arizona