1. Department of Neurosurgery, University of Baghdad, College of Medicine, Baghdad, Iraq
2. Department of Neurosurgery, University of Mustansiriyah, College of Medicine, Baghdad, Iraq,
3. Department of Neurosurgery, Hannover Medical School, Hannover, Germany,
4. Department of Neurosurgery, Neurosurgery Teaching Hospital, Baghdad, Iraq,
5. Department of Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States.