1. Department of Neurosurgery, İstanbul Training and Research Hospital, Istanbul, Turkey
2. Department of Neurosurgery, Yeditepe University School of Medicine, Istanbul, Turkey
3. Department of Neurosurgery, Dr. Lütfi Kırdar Kartal Training and Research Hospital, Istanbul, Turkey
4. Department of Neurosurgery, Ereğli State Hospital, Zonguldak, Turkey