1 Department of Neurosurgery, Banner University Medical Center, PO Box 245070, 1501 North Campbell Avenue, Room 4303, Tucson, AZ 85724-5070, USA. Electronic address: rjhurlbert@email.arizona.edu.
2 Department of Neurological Surgery, University of Miami Miller School of Medicine, Lois Pope Life Center, 1095 Northwest 14th Terrace, Suite 2-24, Miami, FL 33136, USA.
3 Division of Neurosurgery, Department of Surgery, University of Toronto, Division of Neurosurgery, Toronto Western Hospital, University Health Network, Toronto, ON, Canada.