[1] Royal London Hosp, Dept Neurosurg, London, England
[2] Western Gen Hosp, Div Neurosurg, Dept Clin Neurosci, Edinburgh, Midlothian, Scotland
[3] Addenbrookes Hosp, Div Neurosurg, Dept Clin Neurosci, Cambridge CB2 0QQ, England
[4] Univ Cambridge, Cambridge CB2 0QQ, England
[5] Wessex Neurol Ctr, Dept Neurosurg, Southampton, Hants, England
[6] Univ Southampton, Southampton, Hants, England
[7] Royal Victoria Infirm, Dept Neurosurg, Newcastle Upon Tyne, Tyne & Wear, England
[8] John Radcliffe Hosp, Dept Neurosurg, Oxford, England
[9] Walton Ctr, Dept Neurosurg, Liverpool, Merseyside, England
[10] Cambridge Biomed Campus, Cambridge Clin Trials Unit, Surg Theme, Cambridge, England