1. Department of Neurosurgery, Klinikum rechts der Isar, Technical University of Munich;
2. Department of Neurosurgery, University Clinic Johannes Gutenberg–University Mainz;
3. Department of Neurosurgery, University Medical Center Hamburg-Eppendorf;
4. Department of Neurosurgery, University of Geneva Medical Center, Geneva, Switzerland; and
5. Department of Neurosurgery, Medical University Innsbruck, Austria
6. Department of Neurosurgery, Helios Clinic, Krefeld, Germany;
7. Department of Neuroradiology, Klinikum rechts der Isar, Technical University of Munich;
8. Institute for Medical Statistics and Epidemiology, Technical University of Munich;
9. Department of Neurosurgery, Charité University, Berlin;