1. Department of Neurosurgery, University Medical Center Freiburg, Freiburg, Germany
2. Department of Neurosurgery, University Hospital Essen, Essen, Germany
3. Department of Neurology, University Medical Center Freiburg, Freiburg, Germany
4. Institute for Medical Biometry and Medical Informatics, University Medical Center Freiburg, Freiburg, Germany
5. Department of Neuroradiology, University Medical Center Freiburg, Freiburg, Germany