1. Department of Neurosurgery and Spine Surgery University Hospital Essen Essen Germany
2. Institute for Medical Informatics Biometry and Epidemiology University Hospital of Essen Essen Germany
3. Department of Neurology, Division of Epilepsy University Hospital Essen Essen Germany
4. Department of Diagnostic and Interventional Radiology and Neuroradiology University Hospital Essen Essen Germany