Cervical Spine Injuries in Children Restrained in Forward-Facing Child Restraints: A Report of Two Cases

Evaluation of Rotation Reduction Features in Infant and Extended-Use Convertible Child Restraint Systems during Frontal and Rear Impacts

A correctly used child restraint system (CRS) is associated with a substantial reduction of injury and mortality risks in motor vehicle crashes and epidemiologic data suggests that toddlers are provided greater protection when restrained in a rearward-facing CRS compared to a forward-facing CRS. Some 'extended-use' European CRS models can accommodate children up to six years rearward-facing and have a support (load) leg and/or a pair of lower (Swedish) tethers to reduce rotation during frontal and rear impacts, respectively. Laboratory studies have found that a support leg reduces head and neck injury metrics of anthropomorphic test devices (ATDs) younger than three years in rearward-facing CRS models during frontal impacts. The objectives of the current study were to perform sled tests to: (1) evaluate the effects of using a support leg in rearward-facing infant and extended-use convertible CRS models during frontal impacts, (2) evaluate the effects of using a pair of lower tethers in a rearward-facing extended-use convertible CRS model during rear impacts and (3) compare responses of ATDs in an extendeduse convertible CRS with a support leg and a pair of lower tethers in rearward- and forward-facing configurations during frontal and rear impacts. The presence of a support leg in rearward-facing infant and extended-use convertible CRS models in frontal impacts was associated with reductions in head injury metrics across a range of pediatric ATDs and neck injury metrics were below injury tolerance values. Other strategies in the design of rearward-facing CRS and front row vehicle seatbacks may be available to further reduce head injury metrics. Lower tethers reduced the rearward rotation of an extended-use convertible CRS toward the vehicle seatback in rear impacts and were typically associated with reductions in head and neck injury metrics for the Q6 ATD, but not the Q3 ATD. For frontal impacts, neck injury metrics were typically greater for ATDs in the forward-facing extended-use convertible CRS, whereas head injury metrics were typically greater for the rearward-facing condition (with a support leg and a pair of lower tethers). Interactions of the ATD head and/or the rearward-facing extended-use convertible CRS with the blocker plate in rearward-facing frontal impacts need to be further investigated.

Injuries of the Upper Cervical Spinal Column are Markers of Severe Forces in the First Two Years of Life

Cervical spinal column injuries occur uncommonly in infants and young toddlers, and rarely in the upper cervical spine. Any injury, when discovered at forensic autopsy, must be interpreted within the context of a complete case investigation, and available science. When severe upper cervical spinal column injury is detected, such as atlanto-occipital dislocation (AOD), atlanto-axial dislocation (AAD) or spinal cord transection, forensic pathologists commonly regard such trauma as a marker of significant forces. This retrospective study evaluated 60 cases of accidental and homicidal deaths occurring in the first 24 months of life and investigated by a large metropolitan medical examiner jurisdiction. All cases with AOD, AAD or spinal cord transection occurred under documented accidental circumstances, and all of those cases involved severe forces, including being struck by or run over by a car. While such high cervical spinal column pathology is not unusual when an infant or young toddler is struck by or run over by a motor vehicle, or other accidental circumstance involving severe forces, this discovery in a case of apparent natural death or death following alleged short fall or other commonplace activity of daily living should be considered highly suspect.

Discrepancies between knowledge and practice of childhood motor vehicle occupant safety in Nova Scotia--a population-based study

OBJECTIVES

To determine discrepancies between knowledge and practice of childhood motor vehicle restraints (CMVRs) and vehicle seating position amongst parents within the province of Nova Scotia.

DESIGN

Random telephone survey.

SETTING

The Canadian province of Nova Scotia.

SUBJECTS

Four hundred and twenty-six households with at least one child under the age of 12 years, totaling 723 children.

MAIN OUTCOME MEASURES

The proportion of parents whose children who should be in a specific stage of CMVR and sitting in the rear seat of the vehicle, and who demonstrate correct knowledge of that restraint system and seating position, yet do not use that restraint system/seating position for their child (demonstrate practice discrepant from their knowledge).

RESULTS

Awareness of what restraint system to use is good (>80%). However, knowledge of when it is safe to graduate to the next stage is low (30-55%), most marked for when to use a seatbelt alone. Awareness of the importance of sitting in the rear seat of a vehicle was universal. Discrepancies between knowledge and practice were most marked with booster seats and rear-seating of older children. Factors influencing incorrect practice (prematurely graduated to a higher-level restraint system than what is appropriate for age and weight) included lower household income, caregiver education level, and knowledge of when to graduate from forward-facing car seats and booster seats. Incorrect practice was also more commonly observed amongst children of weight and/or age approaching (but not yet reaching) recommended graduation parameters of the appropriate CMVR.

CONCLUSIONS

Discrepancies between knowledge and practice are evident through all stages of CMVRs, but most marked with booster seats. The roles of lower socioeconomic status and gaps in CMVR legislation, in influencing discrepant practice, must be acknowledged and suggest the need for targeted education concurrent with development of comprehensive all-stages CMVR policies.

Clearing the cervical spine in children

Increasing evidence from adult trauma patients has allowed the formation of some international consensus on clearance protocols. The evidence for paediatric trauma remains more fragmented, making the creation of definitive protocols difficult. Spinal injury in children differs from that in adults by injury distribution and prevalence, as well as anatomical and radiological differences. This complicates the process of clearance of the cervical spine in children. The evidence for clearance can be considered in terms of three groups of patients – the alert and asymptomatic child, the conscious child with high-risk criteria and the unconscious or obtunded child. This systematic review summarises the available evidence to clarify the current best practice for each group of patients.