1. Harborview Injury Prevention and Research Center,
2. Departments of Epidemiology,
3. Health Services, and
4. Departments of Pediatrics,
5. Anesthesiology and Pain Medicine,
6. Neurological Surgery, and
7. Biostatistics, School of Public Health, and
8. Rehabilitation Medicine, School of Medicine, University of Washington, Seattle, Washington; and
9. Center for Injury Research and Prevention, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania