Object:​ Spine fractures are a significant cause of morbidity and mortality after motor vehicle crashes (MVCs). Public health interventions, such as the National Highway Traffic Safety Administration's Federal Motor Vehicle Safety Standards, have led to an increase in automobiles with air bags and the increased use of seat belts to lessen injuries sustained from MVCs. The purpose of this study was to evaluate secular trends in the occurrence of spine fractures associated with MVCs and evaluate the association between air bag and seat belt use with spine fractures.

Methods:​ Using the Crash Outcome Data Evaluation System, a database of the police reports of all MVCs in Wisconsin linked to hospital records, the authors studied the occurrence of spine fractures and seat belt and air bag use from 1994 to 2002. Demographic information and crash characteristics were obtained from the police reports. Injury characteristics were determined using International Classification of Disease, 9th Revision, Clinical Modification (ICD-9-CM) hospital discharge codes.

Results:​ From 1994 to 2002, there were 29,860 hospital admissions associated with automobile or truck crashes. There were 20,276 drivers or front-seat passengers 16 years of age and older who were not missing ICD-9-CM discharge codes, seat belt or air bag data, and who had not been ejected from the vehicle. Of these, 2530 (12.5%) sustained a spine fracture. The occurrence of spine fractures increased over the study period, and the use of a seat belt plus air bag, and of air bags alone also increased during this period. However, the occurrence of severe spine fractures (Abbreviated Injury Scale Score ≥3) did not significantly increase over the study period. The use of both seat belt and air bag was associated with decreased odds of a spine fracture. Use of an air bag alone was associated with increased odds of a severe thoracic, but not cervical spine fracture.

Conclusions:​ Among drivers and front-seat passengers admitted to the hospital after MVCs, the occurrence of spine fractures increased from 1994 to 2002 despite concomitant increases in seat belt and air bag use. However, the occurrence of severe spine fractures did not increase over the study period. The use of both seat belt and air bag is protective against spine fractures. Although the overall increased occurrence of spine fractures may appear contrary to the increased use of seat belts and air bags in general, it is possible that improved imaging technology may be associated with an increase in the diagnosis of relatively minor fractures. However, given the significant protective effects of both seat belt and air bag use against spine fractures, resources should continue to be dedicated toward increasing their use to mitigate the effects of MVCs.