1. Department of Neurosurgery, Universitätsmedizin Berlin–Charité, Berlin, Germany
2. Department of Neurosurgery, Unfallkrankenhaus, Berlin, Germany
3. Department of Paediatric Neurosurgery, Asklepios Children Hospital Sankt Augustin, Bonn, Germany
4. Department of Neurosurgery, Bogenhausen Hospital, München, Germany
5. Department of Neurosurgery, Merheim Hospital, Köln, Germany
6. Department of Neurosurgery, University of Münster, Münster, Germany
7. Department of Neurosurgery, University of Göttingen, Göttingen, Germany
8. Department of Neurosurgery, Kassel Hospital, Kassel, Germany
9. Department of Neurosurgery, Clemens Hospital, Münster, Germany
10. Department of Neurosurgery, Medical School Hannover, Hannover, Germany