1. Department of Surgery, College of Medicine, University of Baghdad, Baghdad, Iraq
2. Department of Neurosurgery, Neurosurgery Teaching Hospital, Baghdad, Iraq
3. Department of Surgery, College of Medicine, The University of Babylon, Hillah, Iraq,
4. College of Medicine, Gulf Medical University, Ajman, United Arab Emirates,
5. Department of Neurosurgery, University of Cincinnati, Cincinnati, United States.