1. Department of Neurosurgery, Mayo Clinic, Rochester, MN 55905, USA
2. Kentucky College of Osteopathic Medicine, University of Pikeville, Pikeville, KY 41501, USA
3. School of Medicine, St. George’s University, West Indies, Grenada
4. College of Osteopathic Medicine, Kansas City University, Kansas City, MO 64106, USA
5. Department of Neurosurgery, Weill Cornell Medical Center/New York Presbyterian Hospital, New York, NY 10065, USA