1. From the Departments of Neurosurgery (O.P.M.T., S.M.A.A.E., G.B.) and Neurology (J.L.), University Hospital Maastricht; Departments of Neurosurgery (O.P.M.T.) and Neurology (C.L.F.), Atrium Medical Center Heerlen; and Departments of Health Organization Policy and Economics (S.M.A.A.E.) and Epidemiology (P.L.), University of Maastricht, the Netherlands.