Frontal Motor Vehicle Collisions Research Articles

Preventive effects of seat belts on traumatic brain injury in motor vehicle collisions classified by crash severities and collision directions.

This study aimed to measure the preventive effect of seat belt on traumatic brain injury (TBI) and to compare the effect according to the crash severities and collision directions. Korea In-Depth Accident Study (KIDAS) has collected vehicle and demographic data on injured occupants involved in motor vehicle collisions (MVCs) who visited three emergency medical centers for calendar years 2011-2016. Primary and secondary end points were TBI (abbreviated injury score 2+) and in-hospital mortality. Crush extent (CE) was classified into 1-2, 3-4, 5-6, and 7-9 according to the crash severity. We calculated adjusted odds ratios (ORs) of seat belts and CE for study outcomes and developed an interaction model in each collision direction using multivariate logistic regression analysis. Of the 2,245 occupants who were injured in MVCs, 295 (13.1%) occupants sustained TBI. In univariate analysis, old age, unbelted status, lateral collision, and higher CE were factors associated with TBI in MVCs. Occupants with belted status was less likely to have TBI and in-hospital mortality compared with those with unbelted status [AORs (95% CI) 0.48 (0.37-0.62) and 0.49 (0.30-0.81), respectively]. In interaction analysis, preventive effects of seat belts on TBI from MVCs were retained within CE 5-6 in frontal MVCs and within CE 1-2 in near side lateral MVCs, and those of seat belts on in-hospital mortality were reserved within CE 3-4 in frontal and rollover MVCs. The preventive effects of seat belts on TBI and in-hospital mortality are preserved within a limited crash severity in each collision direction.

Does obesity affect the position of seat belt loading in occupants involved in real-world motor vehicle collisions?

ABSTRACTObjective: Previous work has shown that the lap belt moves superior and forward compared to the bony pelvis as body mass index (BMI) increases. The goal of this project was to determine whether the location of lap belt loading is related to BMI for occupants who sustained real-world motor vehicle collisions (MVCs).Methods: A national MVC database was queried for vehicle occupants over a 10-year period (2003–2012) who were at least 16 years old, restrained by a 3-point seat belt, sitting in the front row, and involved in a front-end collision with a change in velocity of at least 56 km/h. Cases were excluded if there was not an available computed tomography (CT) scan of the abdomen. CT scans were then analyzed using adipose enhancement of 3-dimensional reconstructions. Scans were assessed for the presence a radiographic seat belt sign (rSBS), or subcutaneous fat stranding due to seat belt loading. In scans in which the rSBS was present, anterior and superior displacement of rSBS from the anterior–superior iliac spine (ASIS) was measured bilaterally. This displacement was correlated with BMI and injury severity.Results: The inclusion and exclusion criteria yielded 151 cases for analysis. An rSBS could definitively be identified in 55 cases. Cases in which occupants were older and had higher BMI were more likely to display an rSBS. There was a correlation between increasing BMI and anterior rSBS displacement (P <.01 and P <.01, right and left, respectively). There was no significant correlation between BMI and superior displacement of the rSBS (P =.46 and P =.33, right and left, respectively). When the data were examined in terms of relating increasing superior displacement of the lap belt with Injury Severity Scale (P =.34) and maximum Abbreviated Injury Score (AIS) injury severity (P =.63), there was also no significant correlation.Conclusion: The results from this study demonstrated that anterior displacement of the radiographic seat belt sign but not superior displacement increased with higher BMI. These results suggest that obesity may worsen horizontal position but not the vertical position of the lap belt loading during real-world frontal MVCs.

The Transforming Face of Fracture Epidemiology: Our Concern.

Dear Editor, We read with interest the Editorial published recently, entitled “The transforming face of fracture epidemiology” (1). The author has rightly pointed out the facts regarding the nonfatal patterns of skeletal fractures, which include the fractures induced by the restraint system like air bags and frontal motor vehicle collisions (2, 3). The various modification in designing of such light motor vehicles is needed to save people from catastrophic events. An input from the trauma centers to these manufacturers can help them in properly designing these motor vehicles. A general campaign among the masses can send a good message to the concerned people. Regarding the second part, children and women are more active than before and are now participating in high-energy recreational and athletic activities. This might be partly influenced by the social factors as well. Children usually indulge in indoor games and are often unattended during play hours (4). Osteoporosis is one of the global burdens in the state economy (5, 6). Proper screening by bone mineral density scan and proper management thereafter can decrease the fracture rate. A coordinated approach is needed to plan a proper strategy for the wellbeing of nation. Having an orthopedic trauma registry can show the actual burden of trauma. Then a plan can be made to prevent or decrease these events.

Computer simulations of obesity effects on occupant injury in frontal impacts

Obese occupants in motor-vehicle collisions experience different injury risks compared to non-obese occupants and there is little data available to explain these differences. The purpose of this study was to examine mechanisms of injury and injury risk to obese male occupants in frontal motor-vehicle collisions. Computer models were created to investigate the contributions of increased occupant mass and the interaction between the obese torso and seatbelt on occupant injury risk. A design-of-experiments approach was used to investigate the effects of body mass index (BMI) on occupant injury while controlling for vehicle environment variables. Results suggest that occupant mass is the most significant factor contributing to different injury risks in obese occupants. Changes in obese torso/seatbelt interaction, due to increased BMI alone, do not significantly affect occupant injury risk. However, changes in torso/seatbelt interaction coupled with increased occupant mass alter the overall kinematics of the occupant causing increased risk of injury to the lower extremities.

The association between knee airbag deployment and knee–thigh–hip fracture injury risk in motor vehicle collisions: A matched cohort study

IntroductionIn the U.S. alone, an estimated 30,000 knee–thigh–hip (KTH) injuries occur annually in frontal motor vehicle collisions. These fractures typically occur through occupant contact with the vehicle's knee bolster. Research has suggested that knee airbags (KABs) can mitigate the forces sustained during this contact, resulting in decreased injury risk; however, previous research has been limited by small sample sizes or by occurring in a controlled setting. The objective of the current study is to determine the effectiveness of KABs on KTH fracture risk using nationally representative, real-world data. MethodsUsing combined data from the Crash Injury Research and Engineering Network and the National Automotive Sampling Survey, a matched cohort study was conducted among front-seat occupants of vehicles involved in a frontal collision occurring from 2000 to 2009. Occupants exposed to a KAB deployment were matched to occupants with no KAB deployment based on age ±5 years, sex, seatbelt use, vehicle seating position (i.e., driver or front passenger), car vehicle body type, collision impact, and sampling weight. A Cox proportional hazards model was used to calculate risk ratios (RRs) and associated 95% confidence intervals (95% CI) to estimate the association between KAB deployment and lower extremity fracture risk. ResultsThere was no association between KAB deployment and risk of lower extremity fracture (RR 0.83, 95% CI 0.52–1.31). A notable pattern in fracture risk, though not statistically significant, was observed, with a decreased risk of hip (RR 0.72, 95% CI 0.26–1.97) and thigh fracture (RR 0.81, 95% CI 0.32–2.05), and an increased risk of tibia/fibula (RR 1.23, 95% CI 0.52–2.90) and foot fracture (RR 1.96, 95% CI 0.72–5.32). ConclusionsThe results of the current study suggest that KABs are not associated with the risk of lower extremity fractures. However, given the small sample size of the current study, it is difficult to definitively say whether the observed injury pattern is representative of the true pattern.

Analysis of Maxillofacial Injuries of Vehicle Passengers Involved in Frontal Collisions

To clarify the incidence and mechanisms of maxillofacial injuries sustained by motor vehicle passengers, in-depth data from the Institute for Traffic Accident Research and Data Analysis, Japan, were retrospectively analyzed. From the Institute for Traffic Accident Research and Data Analysis in-depth data for 1993 through 2005, data were collected for 226 individuals with maxillofacial injuries who were adult passengers involved in frontal motor vehicle collisions. The accident information, a subject's medical data, and anatomic Injury Severity Scores were examined. The median Injury Severity Score was 2, and the mean equivalent barrier speed of the vehicles was 35.2 ± 13.0 km/hour. The most common maxillofacial injuries were lacerations (46.7%), followed by abrasions (41.9%), fractures (14.0%), and dental injuries (5.7%). Maxillofacial fractures occurred more often in unrestrained drivers without airbag deployment (18.4%) and less often in restrained drivers with airbag deployment (4.3%). The incidences of fractures caused by impacts with areas other than the steering wheel were markedly decreased using any safety device (35.5% to 0%). Combined use of seat belts and airbags by occupants decreases fractures compared with completely unrestrained occupants. Furthermore, wearing a seat belt prevents the free flight of drivers within a vehicle and contact with the interior of a vehicle (other than the steering wheel). Although the anatomic Injury Severity Score of maxillofacial injuries was relatively low, because these injuries are also associated with socioeconomic costs, the correct use of safety devices and further development of more effective injury prevention systems are needed.

Injury risks between first- and second-generation airbags in frontal motor vehicle collisions

Background Airbags in vehicles manufactured after 1997 were depowered to decrease injury risks for infants/children and small adults. It is possible that compared to earlier airbags second-generation airbags provide less injury protection due to their depowered nature. Methods A cohort study was conducted using 1995–2004 national data. Risk ratios (RRs) and 95% confidence intervals (CIs) compared injury risks for occupants involved in frontal collisions in vehicles wherein a first- or second-generation airbag deployed by body region and injury severity using the Abbreviated Injury Scale (AIS). Associations were adjusted for crash severity, seatbelt use, seat position, occupant location, and vehicle curb weight. Results For upper extremity injuries reduced RRs were observed for AIS 1 or greater (RR = 0.76, CI 0.67–0.86), AIS 2 or greater (RR = 0.76, CI 0.58–1.00) and AIS 3 (RR = 0.81, CI 0.64–1.03). Elevated risks were observed for AIS 5 thoracic injuries (RR = 1.46, CI 1.04–2.07) but were made null when differences in age and gender were adjusted for. Conclusions Vehicles equipped with first- and second-generation airbags appear to offer similar protection for front-seated occupants. The observed decreased risks for upper extremity injury and increased risks for severe thoracic injuries warrant further attention.

The Association Between Restraint System and Upper Extremity Injury After Motor Vehicle Collisions

This study was designed to investigate the relationship between upper extremity (UE) injuries and occupant restraint systems among front seat occupants who were involved in frontal motor vehicle collisions (MVCs). Case-control. The 1995 through 2002 National Automotive Sampling System (NASS) Crashworthiness Data System (CDS). Subjects were identified from the NASS-CDS. All cases sustained an UE injury with a > or = 2 Abbreviated Injury Scale Score. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated comparing risk of UE in 3 mutually exclusive restraint system groups (seatbelt-only, airbag-only, seatbelt-airbag-combined) to the unrestrained group. Data analysis was adjusted for significant occupant, vehicle, and collision characteristics. Seatbelt-only occupants had a reduced UE injury risk (OR, 0.41; 95% CI, 0.22-0.76). Near null associations were found for airbag-only (OR, 1.1; 95% CI, 0.68-1.76) and seatbelt-airbag-combined (OR, 0.97; 95% CI, 0.56-1.69). The results of this study suggest that UE injuries may become more common as a result of MVCs as the proportion of airbags in motor vehicles increases.

Effect of restraint systems on maxillofacial injury in frontal motor vehicle collisions

Purpose Motor vehicle collisions (MVCs) are the leading cause of maxillofacial fractures. Additionally, maxillofacial injuries are the most common injury related to air bag deployment. We sought to characterize the occupant restraint system (seat belt and air bag) and collision characteristics associated with MVC-related maxillofacial injuries. Materials and methods The 1991–2000 National (United States) Automotive Sampling System Crashworthiness Data System (CDS) data files were used. The CDS is a national probability sample of passenger vehicles involved in police-reported tow-away MVCs. Analysis was limited to front seat occupants involved in frontal collisions of delta-V (estimated change in velocity) of greater than 15 km/hr. The risk of facial injury was calculated according to occupants’ restraint use (unrestrained, seat belt only, air bag only, and seat belt and air bag combined) and compared using risk ratios (RRs) and associated 95% confidence intervals (CIs). Results Occupants restrained with a seat belt only (RR, 0.48; 95% CI, 0.40 to 0.57) or a seat belt and an air bag (RR, 0.83; 95% CI, 0.73 to 0.94) had a significantly reduced risk of any facial injury compared with completely unrestrained occupants. There was no association for those restrained with an air bag only (RR, 1.19; 95% CI, 0.82 to 1.73). A similar pattern of results was observed for moderate to severe facial injuries and for facial fractures. Conclusion Seat belt use significantly reduces the risk of facial injury in frontal MVCs. Air bag use was not associated with the risk of facial injury.

Relationship between age and lower extremity fractures in frontal motor vehicle collisions.

Older adults (aged > or = 65 years) represent the single fastest growing segment of the United States population and will comprise one in five Americans during the third decade of this century. As this population segment rapidly expands, lower extremity fractures (LE Fx) and their associated disability will become a greater public health concern. The purpose of this study was to quantify the risk for LE Fx from motor vehicle collisions (MVCs) according to age. The 1995 to 2000 National Automotive Sampling System data files were used. Study entry was limited to front-seat occupants involved in frontal MVCs. Risk ratios for LE Fx and age were adjusted for gender, driver versus passenger, seat belt use, airbag deployment, delta-V, intrusion, and vehicle type. Beginning in the fourth decade, there was a trend of higher relative risk for LE Fx with age that reached statistical significance in the seventh decade of life. This study documented an increased risk of LE Fx in older MVC occupants. Efforts to prevent these disabling injuries and to better protect occupants' lower extremities in MVCs should include improved vehicle design and reevaluation of the existing federal motor vehicle safety standards.

Prediction of injuries to the heart and thoracic aorta in unrestrained drivers

The purpose of the study was to investigate factors predicting injuries to the heart and/or thoracic aorta (H/TA) of unrestrained drivers in frontal motor vehicle collisions. We retrospectively analyzed findings of forensic autopsies of 37 unrestrained drivers of automobiles without airbags involved in frontal collisions. Mechanisms of injury, injury severity, presence of major injuries, and the number of fractured ribs were examined in each case. Victims were subdivided for comparison into those with (19 cases) and without (18 cases) H/TA injuries. The injury severity score and the abbreviated injury scale of the chest were significantly higher in persons with H/TA injuries (65.3±15.7 and 5.4±0.9) than in persons without (31.6±22.0 and 1.8±1.9). Because univariate analysis showed that the presence of multiple fractured ribs was an important predictor of H/TA injuries, we examined the relation between H/TA injuries and the number of fractured ribs. Copas's nonparametric smooth binary regression model showed that H/TA injuries were more likely in persons with eight or more fractured ribs. The presence of eight or more fractured ribs predicts H/TA injuries in unrestrained drivers.