1. Department of Neurosurgery, Louisiana State University Health Sciences Center-New Orleans, New Orleans, Louisiana.
2. Department of Neurosurgery, University of Louisville, Louisville, Kentucky.
3. Baptist Health Center for Advanced Neurosurgery, Louisville, Kentucky.
4. Department of Biostatistics and Bioinformatics, University of Louisville, School of Public Health and Information Sciences, Louisville, Kentucky.
5. Robley Rex Veterans Affairs Medical Center, Louisville, Kentucky.
6. University of Louisville Physicians, Louisville, Kentucky.