1. Department of Neurosurgery, Recep Tayyip Erdogan University Medical Faculty, Rize, Turkey.
2. Department of Neurosurgery, Karadeniz Technical University Medical Faculty, Trabzon, Turkey.
3. Department of Anestesiology, Sar Hospital, Rize, Turkey.
4. Department of Neurosurgery, Samsun Education and Research Hospital, Samsun, Turkey.