1. Department of Neurosurgery, Medical University of South Carolina, Charleston, South Carolina;
2. College of Medicine, Medical University of South Carolina, Charleston, South Carolina;
3. Department of Neurosurgery, MedStar Georgetown University Hospital, Washington, DC;
4. Department of Surgery, University of Texas Rio Grande Valley School of Medicine, Harlingen, Texas; and
5. Department of Neuroscience, Valley Baptist Medical Center, Harlingen, Texas