[1] Univ Hlth Network, Toronto Western Hosp, Div Rheumatol, Toronto, ON M5T 2A8, Canada
[2] Univ Hlth Network, Toronto Western Hosp, Div Neurosurg, Toronto, ON M5T 2A8, Canada
[3] Univ Toronto, Dept Med, Toronto, ON, Canada
[4] Univ Toronto, Dept Surg, Toronto, ON, Canada