1. Department of Neurosurgery, Stanford University, Palo Alto, California, United States
2. Department of Neurosurgery, King Saud University, Riyadh, Saudi Arabia
3. College of Medicine, King Saud University, Riyadh, Saudi Arabia
4. College of Medicine, University of Dammam, Dammam, Saudi Arabia
5. Department of Medicine, Stanford University, Palo Alto, California, United States