1. Department of Neurosurgery, University Hospital Jena, Jena, Germany
2. Department of Neurosurgery, University Hospital Frankfurt, Frankfurt am Main, Germany
3. Department of Neurosurgery, University of Erlangen-Nürnberg, Erlangen, Germany
4. Department of Neurosurgery, Vivantes Hospital Berlin Neukölln, Berlin, Germany
5. Department of Neurosurgery, University Hospital Carl Gustav Carus, Dresden, Germany