Relationship Between Restraint System Use and Brachial Plexus Injuries in Motor Vehicle Accidents: A Case-Control Study from the National Trauma Databank.

Introduction: High-speed motor vehicle accidents (MVAs) are an important cause of brachial plexus injury (BPI). Some case reports have demonstrated shoulder seat belt use resulting in traction injuries to the brachial plexus. We used a national trauma registry to determine the association between seat belt use and brachial plexus injury in MVAs.

Methods: The authors queried the National Trauma Databank between 2016 and 2017 for patients with a hospital admission following an MVA. Cases with BPI were identified using International Classification of Diseases, Tenth Edition, Clinical Modification, diagnosis codes. Case-control matching by age and sex was performed to identify 2 non-BPI controls for every case of BPI. Multivariable conditional logistic regression adjusting for body mass index, alcohol use, and drug use was then performed to determine the adjusted association between safety equipment use (seat belt use and airbag deployment) and BPI.

Results: A total of 526,007 cases of MVAs were identified, of which 704 (0.13%) sustained a BPI. The incidences of BPI in patients were the following without any protective device (0.16%), with airbag deployment alone (0.08%), with seat belt use alone (0.08%), and with combined airbag deployment and seat belt use (0.07%). Following 1:2 case-control matching by age and sex and multivariable conditional logistic regression, seat belt use (odds ratio [OR] 0.55; 95% confidence interval [CI] 0.42-0.71; P < 0.001) and airbag deployment (OR 0.52; 95% CI 0.33-0.82; P = 0.004) were found to be associated with decreased odds for BPI, with the least odds observed with combined seat belt use and airbag deployment (OR 0.49; 95% CI 0.33-0.74; P = 0.001).

Conclusions: Despite anecdotal evidence suggesting increased likelihood of BPI with shoulder seat belt use, case-control analysis from a national trauma registry demonstrated that both seat belt use and airbag deployment are associated with lower odds of sustaining BPIs in MVAs, with the greatest protective effect observed with combined use. Future studies adjusting for rider location (passenger vs. driver) and other potential confounders such as make, type and speed of vehicle may help further characterize this association.