1 *Department of Neurosurgery, Thomas Jefferson University Hospital, Philadelphia, PA †Division of Neurosurgery, Walter Reed National Military Medical Center, Bethesda, MD ‡Department of Neurological Surgery, Weill Cornell Medicine, Weill Cornell Brain and Spine Center, New York-Presbyterian Hospital, New York, NY §Department of Orthopedic and Trauma Surgery, Infanta Elena Hospital, Madrid, Spain.