1. 1Cleveland Clinic Lerner College of Medicine;
2. 2Cleveland Clinic Center for Spine Health;
3. 3Department of Neurological Surgery, Cleveland Clinic;
4. 4Department of Neurosurgery, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania
5. 5Department of Neurosciences, MetroHealth Medical Center;
6. 6Department of Neurological Surgery, Case Western Reserve University School of Medicine, Cleveland, Ohio; and