1. Department of Neurosurgery, University Hospital Rheinisch-Westfäl Technische Hochschule Aachen, Aachen University, Aachen, Germany
2. Department of Neurosurgery, University Hospital Rheinisch-Westfäl Technische Hochschule Aachen, Aachen University, Aachen, Germany, and Neuro Clinic, Roser Klinik, Stuttgart, Germany
3. Department of Neurosurgery, University Hospital Rheinisch-Westfäl Technische Hochschule Aachen, Aachen University, Aachen, Germany, and Department of Neurosurgery, University Hospital Georg-August-University, Goettingen, Germany