Head Impact Contact Points for Restrained Child Occupants

Center for Injury Research and Prevention at The Children’sHospital of Philadelphia, 34th and CivicCenter Blvd, Suite 1150, Philadelphia, PA 19104, USA.
Traffic Injury Prevention (Impact Factor: 1.41). 03/2012; 13(2):172-81. DOI: 10.1080/15389588.2011.642834
Source: PubMed


Head injuries are the most common injuries sustained by children in motor vehicle crashes regardless of age, restraint, and crash direction. For rear seat occupants, the interaction of the subject with the seat back and the vehicle side interior structures has been previously highlighted. In order to advance this knowledge to the development of countermeasures, a summary of vehicle components that contributed to these injuries is needed. Therefore, the objective of this study was to create a contact map of the vehicle interior for head and face injuries to rear-seated restrained children in front crashes.
The Crash Injury Research and Engineering Network (CIREN) was queried for rear-seated, restrained child occupants (age 0-15 years) in forward-facing child restraints, booster seats, or lap and shoulder belts who sustained an AIS2+ head and/or face injury in a frontal motor vehicle crash. Cases were analyzed to describe injury patterns and injury causation scenarios. A contact point map was developed to summarize the vehicle components related to injury causation of the head/face injury.
Twenty-one cases met the combined inclusion and exclusion criteria. Seven of the child occupants were restrained in forward-facing child restraints, 2 in belt-positioning booster seats, and 12 in lap and shoulder belts. There were 28 head and 17 facial injuries. For left rear occupants, the most common contact point was the pillar in front of the occupant's seat row; that is, B-pillar for second-row occupants, indicating a leftward kinematics. For right rear occupants, due to differences in crash dynamics, the most common contact point location was the passenger's seat back, suggesting that these occupants moved predominantly forward.
Contact points associated with head/face injury for restrained children 0 to 15 years in frontal crashes have been delineated. In a majority of the cases, the head/face injury was the most severe injury and severe injuries to other body regions were uncommon, suggesting that efforts to mitigate head injuries for these occupants would greatly improve their overall safety. The majority of the head/face contact points were to the first row seat back and B-pillar. In these frontal crashes, the importance of head/face contact with the vehicle side structure suggests that deploying a curtain air bag in frontal impacts may help manage the energy of impact. These data advance the current understanding of injury patterns and causation in frontal crashes involving restrained rear-row occupants and can be used to develop solutions to mitigate the injuries sustained.

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    • "Infant head injuries related to MVCs have been attributed to head movement without substantial head contact to any structure or another occupant. This is significantly different from older children in forward-facing restraints, in which head injuries are associated with more skull fractures and with additional head contact points within the vehicle [9]. We have observed that infants involved in moderate to high-speed MVCs often sustain significant head injuries, despite being properly restrained. "
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    ABSTRACT: We observed a high incidence of traumatic brain injuries (TBI) in properly restrained infants involved in higher speed motor vehicle crashes (MVCs). We hypothesized that car safety seats are inadequately protecting infants from TBI. We retrospectively queried scene crash data from our State Department of Transportation (2007-2011) and State Department of Public Health data (2000-2011) regarding infants who presented to a trauma center after MVC. Department of Transportation data revealed 94% of infants in MVCs were properly restrained (782/833) with average speed of 44.6 miles/h when there was concern for injury. Department of Public Health data showed only 67/119 (56.3%) of infants who presented to a trauma center after MVC were properly restrained. Properly restrained infants were 12.7 times less likely to present to a trauma center after an MVC (OR=12.7, CI 95% 5.6-28.8, p<0.001). TBI was diagnosed in 73/119 (61.3%) infants; 42/73 (57.5%) properly restrained, and 31/73 (42.5%) improperly/unrestrained (p=0.34). Average head abbreviated injury scale was similar for properly restrained (3.2±0.2) and improperly/unrestrained infants (3.5±0.2, p=0.37). Car safety seats prevent injuries. However, TBI is similar among properly restrained and improperly/unrestrained infants involved in higher speed MVCs who present to a trauma center.
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    ABSTRACT: Small overlap crashes, where the primary crash engagement is outboard from the longitudinal energy absorbing structures of the vehicle, have received recent interest as a crash dynamic that results in high likelihood of injury. Previous analyses of good performing vehicles showed that 24% of crashes with AIS 3+ injuries to front seat occupants were small overlap crashes. However, similar evaluations have not been conducted for those rear seated. Vehicle dynamics suggest that rear seat occupants may be at greater risk due to lack of lateral seating support and a steering wheel to hold, making them more sensitive to lateral movement seen in these crashes. Thus, the objective was to calculate injury risk for rear-seated occupants in small overlap collisions. AIS 2+ and AIS 3+ injury risk was calculated from NASS-CDS data from 2000-2011. Inclusion criteria were vehicles of model year 2000 or later, with CDC codes of "FL" or "FR", and an occupant in the second or third row. AIS2+ injury risk was 5.1%, and AIS3+ injury risk was 2.4%. Of note, half of the occupants were <15 years of age indicating rear seat protection should emphasize the young. Occupants seated near side were nearly three times as likely to sustain an AIS2+ injury than occupants seated far side. Particular attention should be paid to the prominence of head injuries in this crash dynamic and consideration given to their mitigation. Additional research should determine whether countermeasures being implemented for front seat occupants can be beneficial to rear seat occupants.
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    ABSTRACT: Head injuries are the most common severe injuries sustained by pediatric occupants in road traffic crashes. Preventing children from adopting positions that can result in an increased injury risk due to unfavorable interactions with the restraints is fundamental. The objective of this paper was to assess the effect of a head support system (SS) on the lateral position of the head, the vertical position of the sternum and the shoulder belt fit. Thirty pediatric rear-seat passengers were exposed to two 75-minute trials. Volunteers were restrained by a three-point belt and, if needed, used the appropriate child restraint system for their anthropometry (high-back booster, low-back booster, no booster). A case crossover study was designed in which the volunteers used the head support system (SS) during one of the trials, acting as their own controls (No SS) in the other. Compared to the control group, the head support reduced significantly the 90(th) percentile value of the absolute value of the relative lateral motion of the head, regardless of the restraint used. The system also reduced the maximum downward position of the sternal notch within the low-back booster group. As for the belt fit, the use of the head support improved significantly the position of the shoulder belt on the occupant in the low-back booster and in the no booster groups.
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