1. Department of Neurosurgery, Recep Tayyip Erdogan University, Medical Faculty, Rize, Turkey
2. Department of Neurosurgery, Ataturk University, Medical Faculty, Erzurum, Turkey
3. Department of Neurosurgery, Sisli Etfal Research and Education Hospital, Istanbul Turkey
4. Department of Neurosurgery, Kanuni Research and Training Hospital, Trabzon, Turkey
5. Department of Neurosurgery, Karadeniz Technical University, Medical Faculty, Trabzon, Turkey
6. Department of Pathology, Ataturk University, Medical Faculty, Erzurum, Turkey