1. Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland;
2. Department of Neurosurgery, University of Tennessee Health Science Center, Memphis, Tennessee;
3. Department of Neurosurgery, Tufts Medical Center, Boston, Massachusetts;
4. Department of Neurosurgery, UT Southwestern Medical Center, Dallas, Texas;
5. Department of Neurosurgery, University of Southern California, Los Angeles, California;
6. Department of Neurosurgery, Vanderbilt University, Nashville, Tennessee;
7. Department of Neurosurgery, Baylor College of Medicine, Houston, Texas;
8. Department of Neurological Surgery, Oregon Health & Science University, Portland, Oregon; and
9. Department of Neurological Surgery, Wake Forest University, Winston-Salem, North Carolina