1. Departments of Surgery and
2. Neurosurgery, Amsterdam University Medical Centers, location VUmc, Cancer Center Amsterdam;
3. Department of Neurosurgery, Elisabeth-Tweesteden Hospital, Tilburg;
4. Department of Neurosurgery, Erasmus University Medical Center, Rotterdam;
5. Department of Neurosurgery, Northwest Clinics, Alkmaar;
6. Department of Neurosurgery, Medical Center Slotervaart, Amsterdam;
7. Department of Neurosurgery, Isala, Zwolle;
8. Department of Neurosurgery, Maastricht University Medical Center, Maastricht;
9. Department of Neurosurgery, Haaglanden Medical Center, The Hague;
10. Department of Neurosurgery, Martini Hospital, Groningen;
11. Department of Neurosurgery, Radboud University Medical Center, Nijmegen;
12. Department of Neurosurgery, Leiden University Medical Center, Leiden;
13. Department of Neurology & Neurosurgery, University Medical Center Utrecht;
14. Department of Neurosurgery, Medical Spectrum Twente, Enschede;
15. Department of Neurosurgery, University Medical Center Groningen; and
16. Department of Clinical Epidemiology and Biostatistics, Amsterdam University Medical Centers, Amsterdam, The Netherlands