GP3b - A Comparison of Maxillofacial and Head Injuries Following Electric Scooter and Bicycle Accidents

Abstract: The prevalence of maxillofacial and head injuries associated with electric scooters (e-scooter or ES) has risen in concordance with its popularity. There is evidence that the safety of these e-scooters is of concern. According to the Centers for Disease Control and Prevention (CDC), there are 20 e-scooter accidents for every 100,000 trips.1 A multicenter study comparing e-scooter, motorcycle, and bicycle accidents between 2019 and 2022 found e-scooter road traffic accidents tripled in this period, and e-scooter injuries were as severe as motorbike accidents.2 Unfortunately, these severe injuries may result in permanent esthetic deformities, disability, or even death. The bicycle is one of the most popular modes of transportation in the world and has been studied for nearly 2 centuries, making it the ideal comparison. The purpose of this study was to compare maxillofacial and head injury location, type, and severity related to e-scooter and bicycle accidents and to identify factors contributing to injury severity.

The authors implemented a multicenter retrospective cohort study in Seattle, Washington, and enrolled a sample of ES riders and bicyclists who sustained maxillofacial injuries between September 2020 and September 2022. Exclusion criteria included non-motorized scooters, motorized bicycles, injuries with other operators or vehicles, and pre-evaluation deaths. The predictor variable was vehicle type, bicycle/ES. The outcome variables included maxillofacial injury location – distinguished by horizontal facial thirds – and injury type, defined as hard or soft tissue. Associated head injury type also was reported as hard- (calvaria) or soft- (scalp) tissue injuries. Severity of these injuries was quantified using both the Injury Severity Score (ISS) and face and head Abbreviated Injury Scale (AIS). Demographic, injury, and treatment-related variables were collected. Bivariate, multivariate, and regression statistics were computed. Statistical significance was P < .05.

The final sample was composed of 205 total subjects, of which 52 (25.4%) were in the ES group and 153 (74.6%) in the bicycle group. Isolated midface injuries were the most common hard-tissue location in the ES (15.4%) and bicycle (29.4%) groups. The most common soft-tissue injury location included the upper face and midface in the ES (19.2%) and the midface in bicycle groups (22.9%). Both hard- and soft-tissue head injuries were more prevalent in the ES group (P < .0002 and P < .0001). Moreover, intracranial injuries were seen in 36.5% of ES subjects compared to 9.8% bicycle subjects (P < .0001). Between the 2 groups there was no difference in maxillofacial injury severity, but head injuries were more severe in the ES group (P < .0002). Using regression analysis, drug use was found to have a significant impact on the mean Injury Severity Score (P < .002) and helmet use did not have significant impact on face or head injury severity.

Maxillofacial injury location, type, and severity are comparable among ES and bicycles. However, ES riders are at greater risk of severe head injuries compared to bicycles and riding while intoxicated has the greatest effect on injury severity.

References. Dockless Electric Scooter-Related Injuries Study: Austin Public Health, 2019. Available at https://www.austintexas.gov/. Accessed October 20, 2023.
2. James A, Harrois A, Abback P-S, et al: Comparison of Injuries Associated With Electric Scooters, Motorbikes, and Bicycles in France, 2019-2022. JAMA Netw Open 6: e2320960, 2023.