1. Department of Neurosurgery, Louisiana State University Health Sciences Center, Shreveport, Louisiana
2. Department of Neurosurgery, New York-Presbyterian Hospital/Weill Cornell Medical Center, Cornell University, New York, New York
3. Department of Neurosurgery, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma
4. The Orthwein Brain and Spine Center at St. Luke's Hospital, Chesterfield, Missouri
5. Neurological and Spinal Surgery, San Luis Obispo, California
6. Neuroscience and Spine Institute, Kalispell, Montana
7. Neurological Surgery, PC, Commack, New York
8. NorthBay Center of Neuroscience, Fairfield, California
9. Department of Neurosurgery, Southern Illinois University School of Medicine, Springfield, Illinois
10. Department of Neurosurgery, University of Minnesota, Minneapolis, Minnesota
11. Department of Neurosurgery, Brown University, Providence, Rhode Island
12. Southeastern Neurosurgical and Spine Institute, Greenville, South Carolina