1 Department of Neurosurgery, Medical Faculty, Recep Tayyip Erdogan University, Rize, Turkey. Electronic address: ayhankanat@yahoo.com.
2 Department of Neurosurgery, Aydın Adnan Menderes University Faculty of Medicine, Efeler, Aydın, Turkey.
3 Department of Neurosciences, Division of Neurosurgery, Reproductive and Odontostomatological Sciences, Università degli Studi di Napoli "Federico II", Naples, Italy.