Air Bags, Seat Belts Important In Preventing Spine Fractures

An article and accompanying editorial published in the Journal of Neurosurgery: Spine provide compelling evidence that the combination of air bags and seat belts affords the best protection against spine fractures sustained in motor vehicle crashes. This research examined the records of more than 20,000 crash victims age 16 and older admitted to Wisconsin hospitals after car or truck crashes from 1994 to 2002. 

Article authors are Marjorie C. Wang, MD, MPH, Frank Pintar, PhD, Narayan Yoganandan, PhD, and Dennis J. Maiman, MD, PhD, Department of Neurosurgery, Medical College of Wisconsin, Milwaukee. The editorial was written by Charles H. Tator, MD, PHD, Division of Neurosurgery, Toronto Western Hospital and University of Toronto.

In 2007, there were over 6 million motor vehicle accidents in the United States. Nearly 2.5 million of those accident victims were injured and more than 41,000 lost their lives. “Motor vehicle accidents are the leading cause of spinal cord injury (SCI) in the United States for people age 65 and younger – and spine fractures – are a significant cause of morbidity and mortality,” said Dr. Wang. A spine fracture is a break in one or more of the bones of the spine (vertebrae in the back or neck). Spine fractures can lead to a complete SCI, which may result in some degree of paralysis or even death. Of the 2,530 patients with spine factures analyzed in this study, 64 died in the hospital.

“I commend Dr. Wang and her group for performing this extensive, labor-intensive epidemiological study of motor vehicle crash victims. This research offers an invaluable assessment of air bags and seat belts – two safety measures that when used together – show evidence of decreasing the risk of these traumatic and often devastating injuries,” stated Dr. Tator.

Dr. Wang and her team analyzed the data and correlated the incidence of spine fractures with air bag and seat belt usage. Of the 29,860 motor vehicle crash hospital admissions, a data group of 20,276 drivers and front seat passengers was analyzed. This group met the following criteria: drivers or front seat passengers age 16 or older with complete ICD-9-CM and air bag/seat belt data who were not ejected from the vehicle.

Key research findings include:

• Use of a seat belt and an air bag together was associated with a decreased risk of a spine fracture, including more severe fractures.
• Only 14 percent of the drivers and front seat occupants involved in Wisconsin motor vehicle crashes between 1994 and 2002 were protected by the combination of air bags and seat belts, although this number increased from 1994 to 2002.
• An alarming 38 percent of these crash victims were not wearing seat belts.
• There were 2,530 spine fractures (12.5 percent) identified among the 20,276 hospital admissions: 1,067 cervical fractures, 565 thoracic fractures, and 1,034 lumbosacral fractures. Eighty-two patients (8 percent) with a cervical fracture also had a thoracic and/or a lumbosacral fracture. Fifty-four patients with a thoracic fracture, (10 percent) also had a lumbosacral fracture. Eight percent of these were classified as severe.
• Use of an air bag alone was associated with an increased risk of a severe thoracic spine fracture.

The Wisconsin Department of Transportation has acknowledged that speeding and alcohol are two principal crash factors, as has the National Highway Traffic Safety Administration (NHTSA). “An important step would be to build a national coalition which advocates for reduced speed limits, mandatory installation of air bags, enforcement/use of seat belts, and deployment of electronic data record systems (EDRs) in all cars and trucks,” remarked Dr. Tator.

“It is possible that improved imaging techniques contributed to an increase in the diagnosis of minor spine fractures,” stated Dr. Wang. “However, in our study, patients with spine fractures had longer hospital stays and higher Injury Severity Scores, suggesting that patients with motor vehicle-related spine fractures are more severely injured. Additional research including improved classification of spine fractures will help further clarify the overall public health impact of these injuries. In conclusion, state and national resources should be dedicated towards increasing the use of both air bags and seat belts,” concluded Dr. Wang.

Unrestricted research support was provided by EBI Medical, Inc., and Abbott Spine. Dr. Wang receives unrelated research support from the Robert Wood Johnson Foundation.