1. Neurosurgery Department, School of Medicine, Mengücek Gazi Training and Research Hospital, Erzincan University, 24000 Erzincan, Turkey
2. Neurosurgery Department, American Hospital, 34365 Istanbul, Turkey
3. Neurosurgery Department, School of Medicine, Koc University, Rumelifeneri Yolu Sarıyer, 34450 Istanbul, Turkey