Seatbelt use has increased from 58% in 1994 to a high of 85% last year. We know that seatbelt use saves lives, but trauma professionals are also aware that they can create their own injuries as well. This is a positive trade-off, because belt use prevents injuries that are difficult to treat (e.g. severe brain injury) and produces a higher number of intra-abdominal injuries that are easy to treat.
The spectrum of injuries attributed to seat belt use was finally appreciated in a journal article published 20 years ago this month. The authors wanted to catalog the various injuries seen in belted and unbelted motor vehicle occupants. They reviewed data from the North Carolina Trauma Registry, one of the most sophisticated state registries at the time. Although there were over 21,000 records in the database, only 3,901 involved motor vehicle crashes and had complete data on seatbelt use.
This study found the following:
- Mortality was higher in those not wearing their seat belts (7% vs 3.2%)
- Unbelted had a much higher incidence of severe head injury (50% vs 33%)
- Overall incidence of any abdominal injury was the same for both (14%)
- GI tract injuries were more common in the belted group (3.4% vs 1.8%)
- Solid organ injury was the same
Bottom line: This study sparked the recognition that seatbelts reduce severe head injury but increase the incidence of some hollow viscus injuries. About 514 severe head injuries were prevented in exchange for 21 additional abdominal injuries that were generally easily repaired. Good tradeoff!
Reference: The spectrum of abdominal injuries associates with the use of seat belts. J Trauma 31(6):821-826, 1991.