^*Iowa Spine & Brain Institute, University of Iowa, Waterloo/Iowa City, Iowa

^‡Division of Neurological Surgery and

^**Division of Neurological Surgery, Children’s Hospital of Alabama, University of Alabama at Birmingham, Birmingham, Alabama

^§Department of Neurosurgery and

^‖Department of Orthopaedics, University of Maryland, Baltimore, Maryland

^¶Department of Neurosurgery, Emory University, Atlanta, Georgia

^#Department of Clinical Neurosciences, University of Calgary Spine Program, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada

^‡‡Division of Neurological Surgery, Barrow Neurological Institute, Phoenix, Arizona

^§§Department of Neurosciences, Inova Health System, Falls Church, Virginia

Correspondence: Mark N. Hadley, MD, FACS, UAB Division of Neurological Surgery, 510 – 20th St S, FOT 1030, Birmingham, AL 35294-3410. E-mail: [email protected]