1. Department of Neurosurgery, University of Cincinnati Neuroscience Institute, University of Cincinnati College of Medicine, and Mayfield Clinic, Cincinnati, Ohio
2. Department of Neurosurgery, University of Puerto Rico Medical Sciences Campus, San Juan, Puerto Rico
3. Department of Neurosurgery, Thomas Jefferson University, Philadelphia, Pennsylvania
4. Department of Neurosurgery, University at Buffalo, The State University of New York, Buffalo, New York
5. Department of Neurosurgery, Vanderbilt University, Nashville, Tennessee
6. Department of Neurosurgery, Rush University Medical Center, Chicago, Illinois
7. Department of Neurosurgery, Illinois Neurological Institute, University of Illinois College of Medicine at Peoria, Peoria, Illinois
8. Department of Neurosurgery, University at Albany, The State University of New York, Albany, New York