1. 1Department of Neurological Surgery, University of Southern California, Keck School of Medicine, Los Angeles, California;
2. 2Harvard–M.I.T. Division of Health Sciences and Technology, Harvard Medical School, Boston, Massachusetts;
3. 3Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, Chicago, Illinois;
4. 4Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland; and
5. 5Department of Neurosurgery, Mayfield Clinic and Spine Institute, University of Cincinnati, Ohio