Jocelyn Brown

Serious injury is associated with suboptimal restraint use in child motor vehicle occupants

Aim:  To investigate the relationship between restraint usage and injury outcome in child motor vehicle occupants aged 2–8 years.

Pediatric spinal injury type and severity are age and mechanism dependent

Study Design. Retrospective case review. Objective. This study aims to characterize a broad spectrum of spinal injuries, from minor soft tissue injuries to spinal cord injuries. We hypothesized that the pattern of pediatric spinal injury would depend on age and cause. Summary of Background Data. While pediatric spinal trauma is generally considered to be rare, the impact of serious spinal trauma is considerable, both in medical and socioeconomic terms. Comparison of serious and minor injuries has rarely been carried out for pediatric spinal injury cases. Methods. All children up to age 16 who sustained spinal trauma, as defined by ICD10 codes, at 2 pediatric trauma hospitals in Sydney, Australia were identified (N = 340). Data on injury mechanism (defined as the causative event), type, and spinal level were collected and analyzed using logistic regression. Results. Traffic-related incidents accounted for approximately one third of all spinal trauma and half of serious injuries. The cervical spine was the most frequently injured region, with thoracic and lumbar spine injuries becoming more common with age. The upper cervical spine was more commonly seriously injured in young children, and the lower cervical spine was involved more often in older children. The frequency of minor soft tissue neck injuries increased substantially above the age of 8. Serious spinal injury is more likely to occur in conjunction with multiple trauma. Road traffic incidents were more likely to result in serious spinal injury than falls or sporting incidents. Conclusion. This study has shown that the pattern of spinal injury in children is related to age and also the mechanism of injury. While traffic-related incidents are a leading cause of injury across all age groups, emphasis on fall prevention is needed for younger children. Older children, particularly boys, are sustaining spinal trauma in sporting and recreational activities.

Age-Specific Parental Knowledge of Restraint Transitions Influences Appropriateness of Child Occupant Restraint Use

Objective: To determine the factors that influence appropriate restraint usage by child occupants across the age range for which any type of child restraint may be appropriate (0–10 years). Design: Randomized household telephone survey. Setting: Statewide survey, New South Wales, Australia. Subjects: Parents or carers of children aged 0–10 years. Main outcome measures: Parental reporting of appropriateness of child restraint. Methods: Demographic information and data on age, size, restraint practices, parental knowledge of child occupant safety, and attitude to restraint use was collected using a structured interview. Data were analysed using logistic regression after cluster adjustment. Results: Inappropriate restraint use by children was widespread, particularly in children aged 2+ years. Overall, parental knowledge of appropriate ages for restraint transitions was associated with increased likelihood of appropriate restraint use. Lower levels of formal parental education, larger families, parental restraint non-use, and parent/child negotiability of restraint use were predictors of inappropriate restraint use. For particular child age subgroups, the parental knowledge that predicted appropriate restraint use was specific to that age group. Most parents felt that they knew enough to safely restrain their child, despite widespread inappropriate restraint use. Conclusions: Parents are more likely to make appropriate restraint choices for their children if they possess restraint knowledge specific to their children’s age and size. Educational campaigns may be most effective when they provide information for specific ages and transition points. Strategies to overcome parents’ misplaced confidence that they know enough to restrain their children safely are also indicated.

Association between different restraint use and rear-seated child passenger fatalities: a matched cohort study

OBJECTIVE To investigate the association between restraint use and death in rear-seated child passengers and to examine whether the estimated association varies by restraint type and age. DESIGN Matched cohort study. SETTING All reported crashed passenger vehicles with at least 2 rear-seated child passengers of whom at least 1 died from the US Fatality Analysis Reporting System for 1998 to 2006. PARTICIPANTS Rear-seated child passengers aged 2 to 6 years. INTERVENTIONS Three models of restraint use: (1) no restraint use, any restraint use; (2) no restraint use, recorded improper restraint use (including improper use of seat belts or child restraints, use of shoulder-only seat belts, and use of an unknown type of restraint), any other restraint use; and (3) no restraint use, improper restraint use, seat belts, and child restraints. Main Outcome Measure Death within 30 days of a crash. RESULTS Compared with no restraint use, being restrained reduced the risk of death in rear-seated child passengers (relative risk [RR], 0.33; 95% confidence interval [CI], 0.22-0.49). Compared with improper restraint use, any other restraint use reduced the risk of death (RR, 0.46; 95% CI, 0.20-0.63). The RR of death for using child restraints compared with seat belts was 0.91 (95% CI, 0.57-1.14). Child restraints performed slightly better in fatality risk reduction in children aged 2 to 3 years (RR, 0.24; 95% CI, 0.09-0.33) than in children aged 4 to 6 years (RR, 0.32; 95% CI, 0.11-0.44) compared with traveling unrestrained. CONCLUSIONS This study demonstrates the protective effects of restraints for child passengers and highlights the importance of using restraints correctly.

A matched-cohort analysis of belted front and rear seat occupants in newer and older model vehicles shows that gains in front occupant safety have outpaced gains for rear seat occupants

Previous studies have suggested that rear seat occupants are at lower risk of serious injury and death in crashes. However, over the last 10-15 years there have been significant changes in front seat safety systems. The aim of this study was to determine whether there is still a benefit for rear seated occupants compared to front seat occupants. A matched-cohort approach, using data on restrained occupants from the US National Automotive Sampling System (data years 1993-2007), was adopted. Conditional poisson regression modeling was used to evaluate the relative risk of AIS3+ injury in front (passenger and driver) and rear seat occupants, in vehicles of model year 1990-1996 compared to newer vehicles. Occupant age, belt type, and intrusion were additional variables in the model. The relative risk of AIS3+ injury for front and rear occupants was influenced by age and model year. For those aged 16-50 years in older vehicles, the front and rear seat offered similar levels of protection (RR=1.14, CI=1.09-1.19), however in newer model vehicles (1997-2007), the rear seat carried a higher risk of injury (RR=1.98, CI=1.90-2.06). For adults over 50 years, the rear seat carried a higher risk in both older and newer vehicles, and for 9-15 year olds, the rear seat carried a lower risk. These findings suggest that safety for front seat occupants has improved over the last decade, to the point where, for occupants over 15 years of age, the front seat is safer than the rear seat. While the benefit of rear seating for children aged 9-15 years has decreased over time, they are still at lower risk in the rear seat.

Population-level estimates of child restraint practices among children aged 0-12 years in NSW, Australia

This cross-sectional study provides population-referenced data on the restraints used and the extent of incorrect restraint use, among child vehicle passengers aged 0-12 years in NSW, Australia. A multistage stratified cluster sampling plan was used to randomly select vehicles from baby/child health clinics, pre-schools/day care centres, and primary schools across NSW to undergo detailed inspection of restraints used by child occupants within those vehicles. Overall, there were very high restraint usage rates (>99% of sampled children) but fewer than one quarter of children were using the correct size-appropriate restraints. Incorrect use (51.4%) was as common as inappropriate use (51.2%). Incorrect use was highest among users of dedicated child restraint systems (OR 16.0, 95% CI 6.9-36.0), and was more likely among those using size-appropriate restraints than those using inappropriate restraints (OR 1.8 95% CI 1.1-3.2); and among convertible restraints than those designed for a single mode of use (OR 1.5 95% CI 1.2-1.7). As incorrect use substantially reduces the protection from injury that is offered by child restraints, it is important that future strategies to reduce casualties among child occupants target both inappropriate and incorrect use.

Reconstruction of Crashes Involving Injured Child Occupants: The Risk of Serious Injuries Associated with Sub-Optimal Restraint Use May Be Reduced by Better Controlling Occupant Kinematics

Objective. To determine whether injuries to sub-optimally restrained child occupants in real-world crashes were likely to be preventable by alternative restraint usage practices and to assess the usefulness of crash reconstruction for exploring injury mechanisms in child occupants. Methods. Real-world crashes in which child occupants sustained significant injuries were reconstructed on a laboratory crash sled using the Hybrid III family of child dummies. Alternative restraint scenarios and cases in which children were not seriously injured were also simulated to compare dummy kinematics and dynamic responses in optimal restraint configurations. Results. Restraint misuse was associated with greater motion of the dummy torso and head during crashes, often allowing contact between the child and the vehicle interior, resulting in injury. Poor pre-crash posture for a child inappropriately restrained in an adult belt appeared to worsen the geometry of the sash (shoulder) belt, resulting in a cervical injury due to direct interaction with the belt. Dynamic dummy data did not appear to discriminate between injury and non-injury cases. Conclusions. Dummy kinematics suggest that injuries in which inappropriate use and misuse were a factor were less likely if the most appropriate restraint was used correctly. Adequately controlling the head and upper body of the child occupant was seen to prevent undesirable interactions with the vehicle interior and restraint system, which were associated with injury in the real world. Neck forces and moments and injury criteria calculated from these did not predict injury reliably.

Crash characteristics of older pedestrian fatalities: dementia pathology may be related to 'at risk' traffic situations.

Older people are over represented among pedestrian casualties, and cognitive decline is an often cited possible contributory factor. Cognitive decline and dementia are intimately associated, however the role dementia might play in older pedestrian crashes has received little attention. This study describes crash characteristics for 52 fatally injured older pedestrians in the Sydney metropolitan area. It investigates the relationship between the extent of neurofibrillary tangles (NFT), a hallmark of Alzheimers disease in the brain, and particular crash situations. The results demonstrate crash characteristics that are similar to that reported in other studies of older pedestrians. Furthermore, the results suggest that cognitive decline associated with dementia related neuropathology may be associated with specific crash situations. Compared to older pedestrians with no, or low NFT, those with moderate to high NFT were more likely to be: at least partially responsible for the incident; injured while in low complexity situations; involved in impacts with reversing vehicles; impacted in near lanes of traffic; and struck by a vehicle off road. While described as trends only (p<0.2), these findings highlight areas of concern for older pedestrians and suggest potential targets for engineering and behaviour-based countermeasures aimed at reducing casualty numbers among older pedestrians.

Factors predicting incorrect use of restraints by children travelling in cars: a cluster randomised observational study

Background The benefits of correctly using size-appropriate restraints for children travelling in cars are well established, and considerable research has focused on the determinants of appropriate restraint choice. There are few studies of the factors associated with incorrect use. Objective To determine predictors of incorrect restraint use by child occupants and how these differ from inappropriate use. Methods A stratified multistage cluster sample of child occupants aged 0–10 years in New South Wales, Australia was used. Observation of restraint type and inspection of correctness of use was performed on arrival at schools, childcare centres, and child health clinics. An interview was conducted with the driver. Logistic regression was performed to estimate the effects of parental, family, and other characteristics on the likelihood of moderate or serious incorrect restraint use for restraint classes (rear/forward facing, booster, and seatbelt). Results Significant factors varied depending on age and restraint class. Older child restraint users (OR per year of age 0.27, 95% CI 0.07 to 0.98) and seatbelt users (OR per year of age 0.54, 95% CI 0.45 to 0.64) were less likely to be incorrectly using their restraints than younger users. Child restraint and booster users from non-English speaking families were more likely to be incorrectly using their restraints. Having more children in the car appeared to reduce incorrect use for booster (OR 0.18, 95% CI 0.06 to 0.57) and seatbelt users (OR 0.39, 95% CI 0.16 to 0.93). Conclusions There is a need to reduce incorrect restraint use by both education and improved restraint design. Education aimed at reducing incorrect use may need to be targeted differently to appropriate use programmes, as the predictive factors differ.

Improved Protection for Children in Forward-Facing Restraints During Side Impacts

Objective:This study aims to determine the potential for improved child occupant protection in side impacts that can be obtained using rigid and semi-rigid anchorage systems and the addition of energy-absorbing padding in the side structures of child restraints. Methods:This study uses a comprehensive set of simulated side impacts to evaluate the potential for improved side impact protection in forward-facing child restraints. Factors investigated included methods of anchoring the restraint to the vehicle, energy-absorbing materials in the side structure of restraints, and design features of the restraints such as side wing geometry and seat belt routing. Results:The results show clearly that completely rigid lower attachment of restraints offers the potential for great reductions in head injury risk, which anchorage systems employing a combination of a rigid anchorage bar and webbing attached to a child restraint cannot match. The addition of energy absorbing material in the side structure of restraint systems is effective when the head is fully contained within an adequately designed side wing structure. For restraints anchored by seat belts and loop style semi rigid anchorage straps, belt routing has the potential to significantly affect occupant head excursion. Conclusions: The results suggest that current child restraint standards and consumer testing protocols do not adequately encourage best practice design of child restraints for side impact protection.