1. Division of Neurosurgery, Dalhousie University, Halifax, Nova Scotia, Canada;
2. Division of Neurosurgery, McMaster University, Hamilton, Ontario, Canada;
3. Department of Clinical Neurological Sciences, Western University, London, Ontario, Canada;
4. Université de Laval, CHU de Québec Hôpital-Enfant-Jésus, Laval, Québec, Canada;
5. Division of Neurosurgery, University of British Columbia, Vancouver, British Columbia, Canada;
6. Division of Neurosurgery, University of Calgary, Calgary, Alberta, Canada;
7. Division of Neurosurgery, University of Alberta, Edmonton, Alberta, Canada; and
8. Division of Neurosurgery, Université de Sherbrooke, Sherbrooke, Québec, Canada