1. From Health Services Research Unit (J.L., B.C.R., J.H.v.d.M., J.P.B.), Department of Public Health and Policy, London School of Hygiene & Tropical Medicine, London, UK; Clinical Trials and Evaluation Unit (B.C.R.), Clinical Science South Bristol, University of Bristol, UK; Department of Neurosurgery (K.W.L.), Southern General Hospital, Glasgow, UK; Clinical Effectiveness Unit, Royal College of Surgeons of England (J.v.d.M., L.C., J.P.B.), UK; Department of Neurosurgery (P.J.K.), University of...