1. 1Department of Neurological Surgery, University of California, San Francisco, California;
2. 2Alan and Jacqueline Stuart Spine Research Center, Department of Neurosurgery, Lahey Hospital and Medical Center, Burlington, Massachusetts;
3. 3Wallace Trials Center, Greenwich Hospital, Greenwich, Connecticut;
4. 6Carolina Neurosurgery & Spine, Charlotte, North Carolina;
5. 5Department of Neurosurgery, University of Virginia, Charlottesville, Virginia;
6. 7Rutgers New Jersey Medical School, Newark, New Jersey;
7. 8Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, Tennessee;
8. 9Department of Clinical Neurosciences, University of Calgary Spine Program, Calgary, Alberta, Canada;
9. 4Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania;
10. 10Department of Neurosurgery, Columbia University, New York, New York;
11. 11Department of Neurosurgery, Yale University School of Medicine, New Haven, Connecticut; and
12. 12Department of Neurological Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin