1. Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, United States
2. Department of Neurosurgery, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States
3. Department of Neurosurgery, Thomas Jefferson University, Philadelphia, Pennsylvania, United States
4. Department of Neurosurgery, University of California, Los Angeles, Los Angeles, California, United States
5. Department of Neurosurgery, New York University, New York, New York, United States
6. Department of Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States
7. Department of Neurosurgery, Stanford University, Palo Alto, California, United States
8. Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California, United States
9. Department of Neurosurgery, University of Utah, Salt Lake City, Utah, United States
10. Department of Neurosurgery, Washington University School of Medicine, St. Louis, Missouri, United States
11. Department of Neurosurgery, Cleveland Clinic Foundation, Cleveland, Ohio, United States
12. Department of Neurosurgery, University of Missouri, Columbia, Missouri, United States