1. Spinal Cord Injury Service, Veteran Affairs Palo Alto Health Care System, Palo Alto, California.
2. Department of Neurosurgery, Stanford University, Stanford, California.
3. Department of Population Health Sciences, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin.
4. Department of Biostatistics and Medical Informatics, School of Pharmacy, University of Wisconsin, Madison, Wisconsin.
5. Department of Sonderegger Research Center, School of Pharmacy, University of Wisconsin, Madison, Wisconsin.
6. Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin.