1Division of Neurological Surgery, Barrow Neurological Institute and St. Joseph’s Hospital and Medical Center, Phoenix, Arizona; 2Keck School of Medicine, University of Southern California, Los Angeles, California; 3Department of Neurosurgery, Mayo Clinic, Rochester, Minnesota; 4Department of Neurosurgery, University of California, San Francisco, California; and 5Goodman Campbell Brain and Spine, and Department of Neurosurgery, Indiana University, Indiana University Simon Cancer Center, Indianapolis, Indiana