1. Department of Neurosurgery , Ankara Yıldırım Beyazıt University , School of Medicine , Ankara , Turkey
2. Department of Neurosurgery , Ankara City Hospital , Ankara , Turkey
3. Department of Neurosurgery , Ankara Hacettepei, University , School of Medicine , Ankara , Turkey
4. Department of Pathology , Ankara Yıldırım Beyazıt University , School of Medicine , Ankara , Turkey