1. Department of Neurosurgery, Sana Klinikum Offenbach, Offenbach am Main, Germany
2. Department of Neurosurgery, Mainz University Medical Centre, Mainz, Germany
3. Department of Neurosurgery, Helios Amper Clinic, Dachau, Germany, Germany
4. Department of Neurosurgery, Charing Cross Hospital, Imperial College Healthcare, London, United Kingdom
5. Department of Neurosurgery, Hamad General Hospital, Doha, QATAR
6. Department of Neurosurgery, Saarland University Medical Centre, Homburg, Germany