Motor vehicle restraint system use and risk of spine injury.
OBJECTIVE
Motor vehicle collision (MVC)-related spinal injury is a severe and often permanently disabling injury. In addition, strain injuries have been reported as a common outcome of MVCs. Although advances in automobile crashworthiness have reduced both fatalities and severe injuries, the impact of varying occupant restraint systems (seatbelts and airbags) on thoracolumbar spine injuries is unknown. This study examined the relationship between the occurrence of mild to severe cervical and thoracolumbar spine injury and occupant restraint systems among front seat occupants involved in frontal MVCs.


METHODS
A retrospective cohort study was conducted among subjects obtained from the 1995-2004 National Automotive Sampling System. Cases were identified based on having sustained a spine injury of >/=1 on the Abbreviated Injury Scale (AIS), 1990 Revision. Risk risks (RRs) and 95% confidence intervals (CIs) were computed comparing occupant restraint systems with unrestrained occupants.


RESULTS
We found an overall incidence of AIS1 cervical (11.8%) and thoracolumbar (3.7%) spinal injury. Seatbelt only restraints were associated with increased cervical AIS1 injury (RR = 1.40, 95% CI 1.04-1.88). However, seatbelt only restraints showed the greatest risk reduction for AIS2 spinal injuries. Airbag only restraints reduced thoracolumbar AIS1 injuries (RR = 0.29, 95% CI 0.08-1.04). Seatbelt combined with airbag use was protective for cervical AIS3+ injury overall (RR = 0.29, 95% CI 0.14-0.58), cervical neurological injury (RR = 0.19, 95% CI 0.05-0.81), and thoracolumbar AIS3+ injury overall (RR = 0.20, 95% CI 0.05-0.70).


CONCLUSIONS
The results of this study suggest that seatbelts alone or in combination with an airbag increased the incidence of AIS1 spinal injuries, but provide protection against more severe injury to all regions of the spine. Airbag deployment without seatbelt use did not show increased protection relative to unrestrained occupants.
Reed
Mark A
MA
Center for Injury Sciences, University of Alabama at Birmingham, Birmingham, Alabama, USA.
Naftel
Robert P
RP
Carter
Susanna
S
MacLennan
Paul A
PA
McGwin
Gerald
G
Rue
Loring W
LW
D015998:Abbreviated Injury Scale; D000063:Accidents, Traffic; D017278:Air Bags / Q000009:adverse effects; D015331:Cohort Studies; D006801:Humans; D012189:Retrospective Studies; D012306:Risk; D012622:Seat Belts / Q000009:adverse effects; D013119:Spinal Cord Injuries / Q000453:epidemiology / Q000209:etiology* / Q000517:prevention & control*; D014481:United States / Q000453:epidemiology