1. 5 Azar Hospital, Golestan University of Medical Sciences, Gorgan, Iran
2. Department of Neurosurgery, Golestan University of Medical Sciences, Gorgan, Iran
3. Department of Epidemiology, Mazandaran University of Medical Sciences, Sari, Iran
4. Gorgan Congenital Malformations Research Center, Golestan University of Medical Sciences, Gorgan, Iran
5. Gorgan Congenital Malformations Research Center, Department of Anatomical Sciences, Golestan University of Medical Sciences, Gorgan, Iran