Evaluation of external sources of bladder injury following motor vehicle collisions

Abstract

Introduction/Objective Motor vehicle collisions (MVC) are the leading cause of bladder injury in the United States. The National Automotive Sampling System-Crashworthiness Data System (NASS-CDS), a national population based sample, was used to investigate sources of bladder injury following frontal impact and side impact MVC. Methods We queried the NASS-CDS database from 2000-2008. Possible predictors included primary direction of force, general area of damage, speed change at impact (delta v), seatbelt use, airbag deployment, sex, injury severity score, pelvic Abbreviated Injury Scale (AIS) and specific interior compartment sources. Backward stepwise logistic regression was utilized to assess important predictor variables as a cause of bladder injury following MVC. Final analyses accounted for sampling weights so that odd ratio estimates would be generalizable to the population. Age < 16, rollover MVCs, ejected passengers, and backseat occupants were excluded from analysis. Results After applying sampling weights, 39,721,871 occupants were available for analysis in NASS-CDS. Of these, 5,780 occupants had a bladder injury that allowed determination of frontal or side impact MVC. More injuries were due to front impact (3,155) than side impact (2,625). Following front impact MVC, pelvic AIS (OR 8.52, 95%CI 4.21,17.25) and the restraint system (OR 7.64, 95%CI 1.17,49.89) were significant predictor variables for bladder injury. Among left (driver) side MVCs, pelvic AIS (OR 5.40, 95%CI 3.84,7.59), ISS (1.06, 95%CI 1.04,1.08) and the restraint system (4.11, 95%CI 1.50,11.25) were the only variables that significantly predicted bladder injury. Among right side MVCs, the pelvic AIS (OR 8.72, 95%CI 5.98,12.70) was the only variable that statistically predicted a bladder injury. Conclusion Exploratory analysis reveals there to be significant differences in the internal design elements of automobiles that are associated with bladder injury after MVC. These sources of injury differ depending on front or side impact.