1. From the Department of Neurosurgery (M.S., W.S., D.I.S., M.F.O.), University Clinics of Giessen and Marburg GmbH, Giessen, Germany; the Institute of Quality Assurance Hesse (B.M.), Eschborn, Germany; and the Department of Neurology (G.F.H.), Dr Horst Schmidt Kliniken GmbH, Wiesbaden, Germany.