1 Division of Neurosurgery, McMaster University Faculty of Health Sciences and Hamilton Health Sciences Corporation, 237 Barton Street East, Hamilton, ON, L8L 2X2, Canada. kaspere@mcmaster.ca.
2 Department of Neurosurgery, Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark.
3 Institute of Clinical Medicine, University of Copenhagen, 2300, Copenhagen, Denmark.
4 Department of Clinical Neuroscience, Karolinska Institutet, 171 76, Stockholm, Sweden.
5 Department of Neurosurgery, Western General Hospital, Edinburgh, UK.