1. Department of Neurosurgery, Neurosurgery Teaching Hospital, Baghdad, Iraq
2. Department of Surgery, College of Medicine, Alnahrain University, Baghdad, Iraq
3. Department of Neurosurgery, College of Medicine, University of Baghdad, Baghdad, Iraq,
4. Department of Neurosurgery, College of Medicine, Prince Sattam bin Abdulaziz University, Riyadh, Saudi Arabia,
5. Department of Neurosurgery, University of Cincinnati, Ohio, United States.