The association between restraint system and upper extremity injury after motor vehicle collisions

OBJECTIVES: 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). DESIGN: Case-control. SETTING: The 1995 through 2002 National Automotive Sampling System (NASS) Crashworthiness Data System (CDS). PARTICIPANTS: Subjects were identified from the NASS-CDS. All cases sustained an UE injury with a > or = 2 Abbreviated Injury Scale Score. OUTCOMES: 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. RESULTS: 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). CONCLUSION: 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.     

Seat belts are more effective than airbags in reducing thoracic aortic injury in frontal motor vehicle crashes

BACKGROUND: Airbags reduce the probability of death in frontal collisions, but the effect is small compared with seat belts. Little is known about the influence of seat belts and airbags on the incidence of thoracic aortic injury (TAI). METHODS: The National Automotive Sampling System database was queried for the years 1993 to 1998 to determine the impact of seat belts and airbags on the incidence of TAI in survivors of frontal motor vehicle crashes. Proportions were compared using the two-sample Z test. RESULTS: Seat belts prevent TAI regardless of airbag deployment. The effect of airbags is limited to those wearing seat belts. In frontal collisions without seat belt use, airbag deployment does not alter TAI incidence. CONCLUSION: Seat belts are considerably more effective in preventing TAI than airbags after frontal motor vehicle crashes. Prevention efforts should continue to emphasize the use of active restraints. Restraint use should be considered a risk factor in evaluating patients for potential TAI.     

Seat belt use before and after motor vehicle trauma

BACKGROUND: Motor vehicle crashes cause significant morbidity and mortality annually. Seat belt use has partially been associated with a decreased risk of morbidity and mortality among those involved in motor vehicle crashes. Persons injured in motor vehicle crashes and not wearing seat belts have an increased risk of admission to trauma centers for motor vehicle crash-related injury. The purpose of this study was to measure changes in seat belt use after discharge among patients admitted to a Level I trauma center for injuries sustained in motor vehicle crashes. METHODS: Patients admitted to a Level I trauma center for injuries sustained in motor vehicle crashes during 1998 were eligible for participation. A telephone interview was conducted with a random sample of 136 eligible patients regarding patterns of seat belt use before and after their collision. Demographic data and clinical characteristics were also collected. The frequency of seat belt use before and after crash involvement was compared for all patients and stratified by age, gender, race, and Injury Severity Score (ISS). RESULTS: Slightly over half (54%) of patients reported "always" wearing a seat belt before their collision compared with 85% afterward. Younger age groups, male subjects, and whites had the largest increases in the frequency of seat belt use after collision (45%, 37%, and 44% increases, respectively). With respect to injury severity, the largest increase in the frequency of seat belt use was among those with ISS of 15 to 25 (82% increase). Significant concordance between patient- and emergency medical service-reported use of seat belts was observed. Among subjects reported by emergency medical service personnel to have been restrained, nearly 90% reported belt use at the time of the telephone interview. The most frequently cited occasion for failure to use seat belts (30%) was when taking short trips. Other reported reasons were forgetting to fasten belts (29%), discomfort (10%), being in a rush (8%), riding in the back seat (4%), and that seat belts were unnecessary when riding with a good driver (3%). CONCLUSION: Involvement in a motor vehicle crash results in increased seat belt use. Prevention efforts should be directed toward those patients who report infrequent use. Patient "converts" to seat belt use after collisions may be useful in public awareness and prevention campaigns.     

Restraint use and lower extremity fractures in frontal motor vehicle collisions

BACKGROUND: Seat belts and air bags have been shown to significantly reduce morbidity and mortality following MVCs. Research suggests that restraint use does not protect against lower extremity fracture; however, no population-based studies of this association exist. The purpose of this study is to compare the effectiveness of combined seat belt and airbag restraint systems with airbag alone, seat belt alone, and no restraints with respect to incidence and location of lower extremity fractures. METHODS: A retrospective analysis of front seat occupants involved in police-reported, tow-away frontal MVCs was conducted using data from the 1995 through 2000 National Automotive Sampling System (NASS). Incidence and relative risk (RR) of fracture to specific bony regions were measured according to seat belt use and airbag deployment. RESULTS: Compared with unrestrained occupants, occupants restrained with airbag only had significantly higher risk for all types of lower extremity fractures whereas those occupants restrained with either seat belt only or seat belt and airbag had lower risk of fracture. The greatest difference was seen with tibia/fibula fractures in airbag only (RR, 2.14) but this trend continued to be significant with femur and pelvic fractures (RR, 1.13 and 1.23, respectively). CONCLUSION: While airbags may reduce the risk of death when used alone or in combination with seat belts, the results of this study demonstrate that air bags increase the risk of lower extremity fractures when used as the sole method of passenger protection. Also, they may do so differentially according to skeletal region. This data strongly support the consideration of developing accessory knee bolster airbags to prevent the "submarining" or sliding under the airbag that may be responsible for this finding.     

Humeral shaft fractures as predictors of intra-abdominal injury in motor vehicle collision victims

To assess the utility of humeral shaft fractures as predictors of organ injuries and skeletal injuries in multiply injured patients involved in motor vehicle collisions (MVCs). A prospectively collected database of multiply injured motor vehicle occupants with an Injury Severity Score (ISS) greater than 12 admitted to a level I regional trauma centre during a 102-month period (January 1992 to June 2000) was reviewed to assess skeletal and organ injuries associated with a humeral shaft fracture. The effect of occupant location within the vehicle, the point of collision, and the use of a seat belt restraint was also examined to identify trends in injury patterns. Data from 1070 motor vehicle occupants - 65 with concomitant humeral shaft fractures and 1005 without humeral shaft fractures - revealed that 63% of motor vehicle occupants who sustained humeral fractures were drivers, compared with 77% in the non-humeral fracture group. Those patients who sustained a humeral shaft fracture had a significantly greater number of liver injuries (p = 0.022), forearm/hand fractures (p < 0.001), tibial fractures (p < 0.01) and femoral fractures (p < 0.01) compared with controls. A lateral collision impact showed a trend towards increased splenic and hepatic injuries within the humeral shaft fracture group. The presence of a humeral shaft fracture in a multiply injured patient involved in a MVC is significantly associated with an increased incidence of both upper and lower extremity fractures and liver injury. Moreover, humeral shaft fractures may serve as a predictor of potential intra-abdominal pathology in multiply injured trauma patients involved in MVCs.     

Seat belt use by police: should they click it?

BACKGROUND: Motor vehicle crashes are a leading cause of mortality in the United States, although seat belts significantly reduce the risk of death. Police officers do not always wear a seat belt. A retrospective study was conducted on all crashes that involved marked police vehicles in the United States and included a death in any of the involved vehicles. METHODS: For the years 1997 through 2001, crash data were collected and analyzed from the Fatality Analysis Reporting System that included an isolated or multiple vehicle crash with a marked police vehicle and a resulting death in any of the involved vehicles. Motorcycle, aircraft, and undercover police crashes were excluded from this study. Only the occupants of the police vehicle involved in the crash were included in the study. In addition, crashes involving police vehicles where the status of seat belt use by the occupants of the police vehicle was unknown were also excluded. RESULTS: When the crashes occurred, 59.9% of the officers were responding to nonemergency calls, 79.8% of the occupants were wearing their seat belts, and 79.5% survived. Of the 104 occupants that were not belted, 42 (40.4%) died in the crash, compared with 64 (15.5%) of the 412 belted occupants (risk ratio, 2.6; odds ratio, 3.7). CONCLUSION: The risk of death was 2.6 times higher for unbelted occupants of police vehicles than for belted occupants in our study population. In addition, seat belt use was not statistically related to emergency versus nonemergency calls.     

Occupant and crash characteristics in thoracic and lumbar spine injuries resulting from motor vehicle collisions

Background context

Motor vehicle collisions (MVC) are a leading cause of thoracic and lumbar (T and L) spine injuries. Mechanisms of injury in vehicular crashes that result in thoracic and lumbar fractures and the spectrum of injury in these occupants have not been extensively studied in the literature.

Purpose

The objective was to investigate the patterns of T and L spine injuries after MVC; correlate these patterns with restraint use, crash characteristics, and demographic variables; and study the associations of these injuries with general injury morbidity and fatality.

Study design/setting

The study design is a retrospective study of a prospectively gathered database.

Patient sample

Six hundred thirty-one occupants with T and L (T1–L5) spine injuries from 4,572 occupants included in the Crash Injury Research and Engineering Network (CIREN) database between 1996 and 2011 were included in this study.

Outcome measures

No clinical outcome measures were evaluated in this study.

Methods

The CIREN database includes moderate to severely injured occupants from MVC involving vehicles manufactured recently. Demographic, injury, and crash data from each patient were analyzed for correlations between patterns of T and L spine injuries, associated extraspinal injuries and overall injury severity score (ISS), type and use of seat belts, and other crash characteristics. T and L spine injuries patterns were categorized using a modified Denis' classification to include extension injuries as a separate entity.

Results

T and L spine injuries were identified in 631 of 4,572 vehicle occupants, of whom 299 sustained major injuries (including 21 extension injuries) and 332 sustained minor injuries. Flexion-distraction injuries were more prevalent in children and young adults and extension injuries in older adults (mean age, 65.7 years). Occupants with extension injuries had a mean body mass index of 36.0 and a fatality rate of 23.8%, much higher than the fatality rate for the entire cohort (10.9%). The most frequent extraspinal injuries (Abbreviated Injury Scale Grade 2 or more) associated with T and L spine injuries involved the chest (seen in 65.6% of 631 occupants). In contrast to occupants with major T and L spine injuries, those with minor T and L spine injuries showed a strikingly greater association with pelvic and abdominal injuries. Occupants with minor T and L spine injuries had a higher mean ISS (27.1) than those with major T and L spine injuries (25.6). Among occupants wearing a three-point seat belt, 35.3% sustained T and L spine injuries, whereas only 11.6% of the unbelted occupants sustained T and L spine injuries. Three-point belted individuals were more likely to sustain burst fractures, whereas two-point belted occupants sustained flexion-distraction injuries most often and unbelted occupants had a predilection for fracture-dislocations of the T and L spines. Three-point seat belts were protective against neurologic injury, higher ISS, and fatality.

Conclusions

T and L spine fracture patterns are influenced by the age of occupant and type and use of seat belts. Despite a reduction in overall injury severity and mortality, seat belt use is associated with an increased incidence of T and L spine fractures. Minor T and L spine fractures were associated with an increased likelihood of pelvic and abdominal injuries and higher ISSs, demonstrating their importance in predicting overall injury severity. Extension injuries occurred in older obese individuals and were associated with a high fatality rate. Future advancements in automobile safety engineering should address the need to reduce T and L spine injuries in belted occupants.     

Association between side air bags and risk of injury in motor vehicle collisions with near-side impact

BACKGROUND: Side air bags (SABs) have been introduced in an attempt to reduce the risk of injury in near-side-impact motor vehicle collisions (MVCs). The impact of SABs on MVC-related mortality and morbidity has yet to be evaluated with a large population-based study. The objective of this study was to assess the effectiveness of SABs in reducing the risk of injury or death in near-side-impact MVCs. METHODS: A retrospective study investigated outboard front seat occupants involved in police-reported, near-side-impact MVCs using data from the General Estimates System (1997-2000). The risk of MVC-related nonfatal and fatal injury for occupants of vehicles with and without SABs was compared. RESULTS: Front seat occupants of vehicles with SABs had a risk of injury similar to that of occupants of vehicles without SABs (risk ratio [RR], 0.96; 95% CI confidence interval [CI], 0.79-1.15). Adjustment for the potentially confounding effects of age, gender, seat belt use, seating position, damage severity and location, and vehicle body type did not meaningfully affect the association (RR, 0.90; 95% CICI, 0.76-1.08). CONCLUSIONS: There is no association between the availability of SABs and overall injury risk in near-side-impact MVCs. Future research is necessary to determine the effectiveness of SABs in preventing the injuries for which they were specifically designed.     

Safety belt injury reduction related to crash severity and front seated position

This paper examines the effectiveness of seat belts in reducing injury among passenger car drivers and right front passengers. The analysis is based on more than 1.5 million occupants involved in North Carolina crashes during the years 1973-1981. Initial results show that seat belts reduce the risk of serious injury to the driver by 58% and fatal injury by 73%. For right front passengers, the comparable figures are 53% and 66%. When a measure of vehicle deformity reflecting the severity of the crash is introduced as a control variable, these effectiveness values decline somewhat. Depending on the specific approach taken, seat belts are shown to reduce the risk of serious injury to passenger car drivers by 51-52%, and the risk of fatal injury by 63-67%. For right front passengers, the effectiveness ranges are 43-44% for serious injury and 53-55% for fatal injury. While these adjusted estimates of belt effectiveness are lower than those based on the raw data, they nevertheless represent considerable benefit to car occupants using seat belts.     

Injuries of the thoracolumbar spine associated with restraint use in head-on motor vehicle accidents

Many authors have described spinal and bodily injuries associated with seat belt use. However, most reports have focused primarily on lap seat belts and resultant flexion-distraction injuries. This retrospective chart review studies the relation between the specific type of restraint or air bag and the resultant thoracolumbar spinal injury subtype and associated bodily injuries. The charts of 221 patients who had sustained thoracolumbar fractures in motor vehicle accidents during a 10-year period were reviewed, and 37 patients were identified whose accidents were clearly described as a frontal collision and whose specific form of restraint was recorded. Among the 15 patients who used a shoulder strap and lap belt device (three-point restraint), 12 patients sustained burst fractures (80%) compared with 4 of the 14 patients (28.6%) restrained with lap seat belts alone. Life-threatening intraabdominal injuries occurred in 57.1% of lap-belted victims and in 26.7% of patients who used three-point restraints, and the character of these injuries also differed. No patients in an automobile in which an air bag deployed sustained major associated bodily injuries. Among restrained occupants of head-on motor vehicle accidents who have sustained a thoracolumbar fracture, patients using lap belts are more likely to sustain the classic flexion-distraction injury patterns, whereas patients using three-point restraints may sustain a higher incidence of burst fractures. In addition, three-point restraints are associated with a decreased risk of intraabdominal injury compared with lap seat belts.     

Type II odontoid fracture from frontal impact: case report and biomechanical mechanism of injury

The authors report a case of Type II odontoid fracture from a frontal impact sustained in the crash of a late-model motor vehicle. They discuss the biomechanical mechanisms of injury after considering patient demographic data, type and use of restraint systems including seatbelt and airbags, crash characteristics, and laboratory-based experimental studies. Multiple factors contributed to the Type II odontoid fracture: the patient's tall stature and intoxicated state; lack of manual three-point seat belt use; obliqueness of the frontal impact; and the most likely preflexed position of the head-neck complex at the time of impact, which led to contact of the parietal region with the A-pillar roof-rail area of the vehicle and resulted in the transfer of the dynamic compressive force associated with lateral bending. Odontoid fractures still occur in individuals involved in late-model motor vehicle frontal crashes, and because this injury occurs secondary to head impact, airbags may not play a major role in mitigating this type of trauma to an unrestrained occupant. It may be more important to use seat belts than to depend on the airbag alone for protection from injury.     

The hazards of off-road motor sports: Are four wheels better than two?

BackgroundOff-road motorsports are an increasing popular activity, yet the relative safety profile of all-terrain vehicles (ATV) to off-road motorcycles (ORMC) has not been compared.Study designA retrospective review of the 2002–2006 US National Trauma Data Bank of ATV and ORMC crash victims. Patients were described according to demographic (age, sex, race and ethnicity, insurance status) and injury characteristics (Injury Severity Score, hypotension, motor component of the Glasgow Coma Score, presence of a severe head or extremity injury) known to affect trauma outcomes. Logistic regression evaluated the independent effect of an ATV vehicle on mortality, intensive care unit (ICU) admission, and placement on a ventilator relative to ORMC. The anatomic distribution of severe injuries was compared between survivors and decedents within each vehicle type.ResultsA total of 34,457 patients met inclusion criteria, of whom, 24,582 were ATV patients and 9875 were ORMC patients. ATV patients had 51% higher risk-adjusted odds of death (OR 1.51; 95% CI 1.03–2.20), 55% higher risk-adjusted odds of being admitted to an ICU (OR 1.55; 95% CI 1.42–1.70), and 42% higher risk-adjusted odds of being placed on a ventilator (OR 1.42, 95% CI 1.17–1.72) compared to ORMC crash victims. Decedents in both vehicle types were more likely to suffer severe head, thoracic, and abdominal injuries relative to their surviving counterparts.ConclusionFor injured riders, ATVs are associated with increased mortality and higher resource utilisation compared to ORMCs. Both groups suffer distinct anatomic injuries, suggesting the need for focused areas of injury prevention planning and research.     

Thoracic aortic injury in motor vehicle crashes: the effect of impact direction, side of body struck, and seat belt use

BACKGROUND: Using in-depth, real-world motor vehicle crash data from the United States and the United Kingdom, we aimed to assess the incidence and risk factors associated with thoracic aorta injuries. METHODS: De-identified National Automotive Sampling System Crashworthiness Data System (U.S.) and Co-operative Crash Injury Study (U.K.) data formed the basis of this retrospective analysis. Logistic regression was used to assess the level of risk of thoracic aorta injury associated with impact direction, seat belt use and, given the asymmetry of the thoracic cavity, whether being struck toward the left side of the body was associated with increased risk in side-impact crashes. RESULTS: A total of 13,436 U.S. and 3,756 U.K. drivers and front seat passengers were analyzed. The incidence of thoracic aorta injury in the U.S. and U.K. samples was 1.5% (n = 197) and 1.9% (n = 70), respectively. The risk was higher for occupants seated on the side closest to the impact than for occupants involved in frontal impact crashes. This was the case irrespective of whether the force was applied toward the left (belted: relative risk [RR], 4.6; 95% confidence interval [CI], 2.9-7.1; p < 0.001) or the right side (belted: RR, 2.6; 95% CI, 1.4-5.1; p < 0.004) of the occupant's body. For occupants involved in side-impact crashes, there was no difference in the risk of thoracic aorta injury whether the impacting force was applied toward the left or toward the right side of the occupant's body. Seat belt use provided a protective benefit such that the risk of thoracic aorta injury among unbelted occupants was three times higher than among belted occupants (RR, 3.0; 95% CI, 2.2-4.3; p < 0.001); however, the benefit varied across impact direction. Thoracic aorta injuries were found to be associated with high impact severity, and being struck by a sports utility vehicle relative to a passenger vehicle (RR, 1.7; 95% CI, 1.2-2.3; p = 0.001). CONCLUSION: Aortic injuries have been conventionally associated with frontal impacts. However, emergency clinicians should be aware that occupants of side-impact crashes are at greater risk, particularly if the occupant was unbelted and involved in a crash of high impact severity.     

The epidemiology and prognosis of patients with massive burns: A multicenter study of 2483 cases

ObjectiveEpidemiological features of massively burned patients in China remains unclear. This study was designed to investigate the epidemiological characteristics and evaluate the burn index (BI) and other risk factors associated with the prognosis of massively burned patients.MethodsData of patients with ≥30% total body surface area burned admitted in 2014 were retrieved from 106 burn centers in the mainland of China. Information of epidemiological features and the outcome were collected for retrospective analysis.ResultsA total of 2483 massively burned patients were included in this study, with a male-to-female ratio of 2.29:1, the mean age of 49.23 ± 16.67 years, mean TBSA of 55.53 ± 21.39% and the mean BI of 39.75 ± 21.59. Scald accounted for 81.07% of the injuries in children, while flame accounted for 66.89% and 74.31% of the injuries in adults and seniors. Approximately 17.76% of the patients were admitted to the local burn center after 6 h of injury, and the wound areas of 1154 (46.48%) patients were covered with folk remedies. The mortality was 9.79%, and the area under the receiver operating characteristic (ROC) curve for BI was 0.941 (95% CI, 0.929–0.954). When the value of BI was above a threshold of 29 in the 0–14 years age group, 43.5 in the 15–59 years age group and 35.5 in the 60 years or older age group, the mortality increased significantly. Multivariate logistic regression analyses showed that the odds ratio (OR) of death increased 6% with an increase in the BI of 1.0. Patients older than 60 years, the admission time longer than 6 h after-injury (adjusted OR, 1.797; 95% CI, 1.179–2.740; adjusted p < 0.001), and patients with a combined inhalation injury (adjusted OR, 6.649; 95% CI, 4.517–9.789; adjusted p < 0.000), were at higher risk of death.ConclusionsThere are etiological characteristics of the different age groups that should be considered for prevention. BI can be a reliable index of prognosis in severely burned patients. The results of the study showed that a large BI, elderly age, delayed admission after injury and combined inhalation injury are the main risk factors for extensively burned patients.     

Motor Vehicle Mismatch-Related Spinal Injury

Abstract

Background/Objective: Motor vehicle collision (MVC)-related spinal cord injury (SCI) is the mostprevalent etiology of SCI. Few studies have defined SCI risk factors. Vehicle mismatch occurs in 2-vehicleMVCs in which there are significant differences in vehicle weight, stiffness, and height. This study examinedSCI risk and vehicle mismatch.

Methods: A matched case-control study using the 1995 to 2003 National Automotive Sampling System(NASS). Study subjects were identified from 2-vehicle MVCs. Cases were occupants who had suffereda cervical, thoracic, or lumbar SCI. Odds ratios (ORs) and 95% confidence intervals (Cis) were calculated.

Results: There were 101,682 cases of SCI matched to 805,091 controls. Occupants of passenger vehiclesinvolved in MVCs with a light truck or van (LTV) were at increased risk for SCI (OR= 1.87, 95% Cl= 1.07-3.24) and this risk was greatest for thoracic SCI (OR= 5.09, 95% Cl= 2.33-11.13). In addition, occupants ofL TVs involved in MVCs with passenger vehicles were at significant increased risk for cervical (OR= 1. 39) andlumbar (OR= 2.65) SCI; and occupants of LTVs involved in MVCs with other LTVs were at increased risk ofany SCI (OR= 2.02, 95% Cl= 1.52-2.69). For these subjects, significant increased risks were seen for all spineregions: cervical (OR= 1.41), thoracic (OR= 2.86), and lumbar (OR= 2.38).

Conclusions: The results of this study suggest that occupants of passenger vehicles are at increased SCI riskwhen involved in 2-vehicle MVCs with L TVs; and that occupants of L TVs are at increased SCI risk, regardless     

Thoracolumbar junction injuries after motor vehicle collision: are there differences in restrained and nonrestrained front seat occupants?

OBJECT: Motor vehicle collision (MVC) is one of the most common causes of thoracolumbar junction (TLJ) injury. Although there is little doubt that the use of seat belts reduces the incidence and severity of TLJ injury after MVC, the mechanism by which this is protective against TLJ injury for drivers and passengers is relatively unknown. METHODS: Thirty-nine patients with TLJ (T11-L2) injury who were front seat occupants of a four-wheeled vehicle at the time of MVC (frontal crash) were admitted between 2000 and 2004. The 39 patients were divided into two groups: 18 who had been restrained and 21 who had not been restrained at the time of the MVC. Patient demographics, including the mean Injury Severity Scale score, incidence of neurological deficit, level of TLJ injury, and type of TLJ injury according to the Denis classification were compared. RESULTS: The incidence of neurological deficit in the restrained group was significantly lower compared with the nonrestrained group (5.6% compared with 33.3%, p < 0.05). The incidence of flexion-distraction/fracture-dislocation injuries in the restrained group was also significantly lower (0.0% compared with 33.3% in the nonrestrained group, p < 0.01). The restrained group was significantly older (37.4 +/- 3.6 years compared with 28.0 +/- 2.5 years in the nonrestrained group, p < 0.05), but otherwise there were no significant differences between the two groups regarding the patients' demographic data. CONCLUSIONS: It is likely that the high incidence of neurological deficit in the nonrestrained front seat motor vehicle occupants who had a TLJ injury was mostly due to the high incidence of flexion-distraction/fracture-dislocation injuries. This retrospective study indirectly shows the efficacy of three-point seat belt systems in reducing the severity of a TLJ injury after an MVC. Compression/burst fractures still occur in restrained front seat occupants, however, and elucidation of the injury mechanism of such axial loading fractures may be important to improve safety further for automobile occupants.     

The association between occupant restraint systems and risk of injury in frontal motor vehicle collisions

BACKGROUND: An evaluation of seat belt use and airbag deployment, either alone or in combination, on risk of injury to specific body regions has yet to be completed. METHODS: A retrospective cohort study of front seat occupants involved in police-reported, tow-away, frontal motor vehicle collisions using data from the 1995 through 2000 National Automotive Sampling System was conducted. Only vehicles with a change in velocity (delta-V) of >/= 15 km/h were included. Risk of injury (Abbreviated Injury Scale score >/= 2) to specific body regions was compared according to seat belt use and airbag deployment. RESULTS: Compared with completely unrestrained occupants, those using a seat belt alone or in combination with an airbag had a reduced overall risk of injury (relative risk, 0.42 and 0.71, respectively); no association was observed for those restrained with an airbag only (relative risk, 0.98). This pattern of results was similar for specific body regions with the exception of the lower extremity, wherein a significantly increased risk was observed for airbag deployment alone. CONCLUSION: Airbag deployment does not appear to significantly reduce the risk of injury either alone or in combination with seat belts. Airbag deployment without associated seat belt use may increase the risk of lower extremity injury.     

THE EFFECTS OF SEAT BELT LEGISLATION ON ROAD TRAFFIC INJURIES

The compulsory wearing of seat belts, first introduced in the world in Victoria in 1970, has effectively reduced the number of deaths and injuries by approximately one-third for car occupants involved in motor vehicle crashes. Initially, the legislation did not apply to children under the age of eight years, but in 1975 a further law was introduced banning children from the front seat of any vehicle unless properly harnessed. Seat belts offer the best protection for front seat drivers and passengers involved in frontal impacts, but offer less protection to the recipient of a side impact. Ten per cent of car. occupants admitted to hospital after a frontal impact show injuries, mostly minor, directly attributable to the wearing of seat belts.     

The effects of seat belt legislation on road traffic injuries.

The compulsory wearing of seat belts, first introduced in the world in Victoria in 1970, has effectively reduced the number of deaths and injuries by approximately one-third for car occupants involved in motor vehicle crashes. Initially, the legislation did not apply to children under the age of eight years, but in 1975 a further law was introduced banning children from the front seat of any vehicle unless properly harnessed. Seat belts offer the best protection for front seat drivers and passengers involved in frontal impacts, but offer less protection to the recipient of a side impact. Ten per cent of car occupants admitted to hospital after a frontal impact show injuries, mostly minor, directly attibutable to the wearing of seat belts.