1. Department of Neurological Surgery, Clinical Neurosciences Center, University of Utah, Salt Lake City, Utah;
2. Department of Neurosurgery, Mayo Clinic, Rochester, Minnesota;
3. Department of Neurosurgery, University of California, San Francisco, California;
4. Norton Leatherman Spine Center, Louisville, Kentucky;
5. Department of Neurosurgery, University of Tennessee, Memphis, Tennessee;
6. Department of Neurosurgery, Indiana University; Goodman Campbell Brain and Spine, Indianapolis, Indiana;
7. Department of Neurosurgery, University of Virginia Health System, Charlottesville, Virginia;
8. Department of Neurosurgery, Carolina Neurosurgery and Spine Associates and Neuroscience Institute, Carolinas HealthCare System, Charlotte, North Carolina;
9. Atlantic Neurosurgical Specialists, Morristown, New Jersey;
10. Department of Neurosurgery, University of Michigan, Ann Arbor, Michigan;
11. Department of Neurosurgery, University of Miami, Miami, Florida;
12. Department of Neurosurgery, Weill Cornell Medical College, New York, New York;
13. Geisinger Health, Danville, Pennsylvania; and
14. Department of Neurosurgery, Duke University, Durham, North Carolina