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