1. Department of Neurosurgery, University Hospital of Bern, Bern, Switzerland
2. Department of Neurosurgery, Medical Center—University of Freiburg, Freiburg, Germany
3. University Institute of Diagnostic and Interventional Neuroradiology, University Hospital of Bern, Bern, Switzerland
4. Department of Neurology, University Hospital of Bern, Bern, Switzerland