Patterns of injury in belted and unbelted individuals presenting to a trauma center after motor vehicle crash: seat belt syndrome revisited

STUDY OBJECTIVE: Investigators have described a "seat belt syndrome" consisting variously of injuries to the lumbar or cervical spine, abdominal contents, or all 3. In this study we sought to identify these and any other patterns of injury associated with seat belt use in patients who presented to a trauma center after a motor vehicle crash. METHODS: The charts of all patients involved in motor vehicle crashes who presented as trauma alerts to the study institution between January 1, 1991, and December 31, 1993, were retrospectively reviewed for data regarding belt use and 35 specific injuries in 7 body regions. We calculated the positive likelihood ratio of injury between belted and unbelted patients, along with 95% confidence intervals. RESULTS: We identified 1,124 patients involved in motor vehicle crashes. Of these subjects, 376 were belted and 544 unbelted; in 204 belt status was unknown. Belted patients were more likely to have sustained sternal fracture than were unbelted patients (4% versus .7%; positive likelihood ratio, 1.97; 95% confidence interval, 1.09 to 3.29) but were less likely to have sustained head injury (30.6% versus 46.0%; positive likelihood ratio, .67; 95% confidence interval, .53 to .83). We noted no statistically significant differences in the rates of other specific injuries, including cervical and lumbar fractures and the need for abdominal surgery. CONCLUSION: Severe injuries of all types occur in both belted and unbelted individuals involved in motor vehicle crashes who present to a typical trauma center. With the exception of sternal fractures, injuries previously associated with the seat belt syndrome occurred in similar proportions of belted and unbelted patients. Head injuries were less frequent. Seat belt use cannot serve as a discriminator for specific injury. A diligent search of all body regions is indicated in both belted and unbelted patients.