1. Department of Neurosurgery, Pamukkale University School of Medicine, Denizli;
2. Department of Neurosurgery, Health Sciences University Diskapi Yildirim Beyazit Training and Research Hospital, Ankara;
3. Department of Neurosurgery, Şişli Hamidiye Etfal Training and Research Hospital, Istanbul; and
4. Department of Neurosurgery, Ankara University School of Medicine, Ibni Sina Hospital, Ankara, Turkey