Belt-induced abdominal injuries in recent frontal impact CIREN cases.

OBJECTIVE: The objective is to report sex-related variation in 3-point belt-related abdominal injuries in Crash Injury Research Engineering Network (CIREN) cases. METHODS: A query of CIREN cases was made for those with the highest ranked Collision Deformation Classification (CDC) to the front plane, a principal direction of force (PDOF) ±20° from 0°, and Abbreviated Injury Scale (AIS) 2+ abdomen injuries attributed to the seat belt. Patterns of injury were categorized as above the crest of the ilium, injuries below the crest of the ilium, and injuries above and below the ilium. This was done in the context of autonomous vehicle occupant kinematics testing results. Twelve 5th and 95th percentile 3-point belt-restrained postmortem human subjects were subjects; test speeds and recline angles varied. Abdomen injuries were anticipated; none were observed. RESULTS: Thirty-five occupants with belt-related abdominal injuries were identified. Seventeen case occupants sustained an injury only within the pelvic contents: 5 women and 12 men. Nine of the 17 were at or above the 81st percentile for height, 13 were between the 62nd and 80th percentile for height, and 4 were less than the 50th percentile for height. CONCLUSIONS: The stature component of the body mass index (BMI) appears to be a plausible candidate for an independent variable that is a contributing factor explaining the incidence of pelvic contents injuries when a 3-point belt-restrained occupant is involved in a frontal impact.

Delta-v slope as an indicator of injury.

OBJECTIVE: This study's objective was to examine a crash severity characteristic and the relationship as an indicator of abdominal injury causation. METHODS: Data were analyzed from 23 CIREN case vehicles involved in a frontal type collision, had an AIS 2+ abdominal injury, and contained an electronic data recorder (EDR) download. Data was downloaded from the NHTSA and IIHS crash test databases for comparison. Data was run through a MATLAB algorithm calculating the maximum velocity-time profile slope. This data was compared to the available crash tests. RESULTS: The CIREN vehicle EDR velocity-time slopes ranged from 233 m/s2 to 434 m/s2 for crashes with a delta-v range of 42 km/h to 77 km/h. NHTSA NCAP comparable data was available for all cases, and the slopes ranged from 263 m/s2 to 405 m/s2 calculated from the collected accelerometer. Three comparable tests were available from the IIHS database and the calculated slopes ranged from 252 m/s2 to 298 m/s2. Four test vehicles had EDR data, two each from NHTSA and IIHS and slopes ranged from 245 m/s2 to 281 m/s2. The crash test EDRs slope calculations were lower than the accelerometer data. Nine of the 12 case vehicles had slope values lower than the comparable NCAP accelerometer velocity-time slopes. CONCLUSIONS: Vehicle velocity-time profile can be beneficial to examine the characteristics of crash severity and potential injury. This small sample of field crashes did not indicate a clear relationship of abdominal injury related to crash severity measured by the EDR delta-v slope. EDR results can be considered when determining crash severity, but the limitations need to be understood.

Crash characteristics and injury patterns of restrained front seat occupants in far-side impacts.

OBJECTIVE: The study was conducted to determine the association between vehicle-, crash-, and demographic-related factors and injuries to front seat far-side occupants in modern environments. METHODS: Field data were obtained from the NASS-CDS database for the years 2009-2012. Inclusion factors included the following: adult restrained front outboard-seated occupants, no ejection or rollovers, and vehicle model years less than 10 years old at the time of crash. Far-side crashes were determined by using collision deformation classification. Injuries were scored using the Abbreviated Injury Scale (AIS). Injuries (MAIS 2+, MAIS 3+, M denotes maximum score) were examined based on demographics, change in velocity, vehicle type, direction of force, extent zone, collision partner, and presence of another occupant in the front seat. Only weighted data were used in the analysis. Injuries to the head and face, thorax, abdomen, pelvis, and upper and lower extremity regions were studied. Odds ratios and upper and lower confidence intervals were estimated from multivariate analysis. RESULTS: Out of 519,195 far-side occupants, 17,715 were MAIS 2+ and 4,387 were MAIS 3+ level injured occupants. The mean age, stature, total body mass, and body mass index (BMI) were 40.7 years, 1.7 m, 77.2 kg, and 26.8 kg/m2, respectively. Of occupants with MAIS 2+ injuries, 51% had head and 19% had thorax injuries. Of occupants with MAIS 3+ injuries, 50% had head and 69% had thorax injuries. The cumulative distribution of changes in velocities at the 50th percentile for the struck vehicle for all occupants and occupants with MAIS 2+ and MAIS 3+ injuries were 19, 34, and 42 km/h, respectively. Furthermore, 73% of MAIS 2+ injuries and 86% of MAIS 3+ injuries occurred at a change in velocity of 24 km/h or greater. Odds of sustaining MAIS 2+ and MAIS 3+ injuries increased with each unit increase in change in velocity, stature, and age, with one exception. Odds of sustaining injuries were higher with the presence of an occupant in the front seat at the MAIS 3+ level, although it was reversed at the lower level. The extent zone of 3+ increased the odds compared to the extent zones of 1 to 2 at both MAIS 2+ and MAIS 3+ injuries. Odds ratios and confidence intervals are given. CONCLUSIONS: The findings are as follows: head and thorax are the more frequently injured body regions, and the prevalence of cranium injuries is similar at both injury severities; thoracic injuries are more prevalent at the MAIS 3+ level; the presence of another front seat occupant plays a role in MAIS 3+ trauma; injuries continue to occur at changes in velocity representative of side impact environments; and mean demographic factors are close to mid-size automotive anthropometry, indicating the need to pursue this line of study. Because data were gathered from only 4 years, it would be important to include additional NASS-CDS database years, rescore injuries from previous years, and analyze other international databases to reinforce these findings for advancing safety for far-side occupants.

Injury patterns to other body regions and load vectors in nearside impact occupants with and without shoulder injuries.

CIREN and NASS-CDS databases were used to analyze nearside impact injuries. Front seat occupants with and without shoulder injuries were examined on an individual basis in both databases. All vehicles were from model year 2000 or newer. Variables such as the type of collision, change in velocity, principal direction force, demographics, injuries scored by the MAIS and ISS metrics, and injuries to the head, thorax, abdomen and pelvis were included. Shoulder injuries included fractures to the humerus, scapula and clavicle, and associated joint traumas. The median changes in velocities for occupants with and without shoulder injuries were 36 and 32 km/h in CIREN and 29 and 32 km/h in NASS databases. Approximately two-thirds of all cases occurred below 40 km/h. In both databases, the clavicle, scapula and humerus fractures, and AC joint dislocations were found, and the scapula fracture was associated with the clavicle, AC joint, acromion and humerus injuries in few occupants. The clavicle fracture was associated with AC joint and humerus injuries only in the NASS database. Thorax, abdomen and pelvic injuries and skull fractures increased with the presence of shoulder injuries in both databases, albeit not at the same rate. Anterior oblique loading was more frequent than pure lateral loading in both databases suggesting the importance of the oblique vector in side impact trauma. These findings underscore a need for detailed examinations of shoulder load-sharing using biomechanical studies to better understand its role in side impact traumas, shoulder biofidelity and injury assessments in dummies.

BioTab--a new method for analyzing and documenting injury causation in motor-vehicle crashes.

OBJECTIVE: To describe a new method for analyzing and documenting the causes of injuries in motor vehicle crashes that has been implemented since 2005 in cases investigated by the Crash Injury Research Engineering Network (CIREN). METHODS: The new method, called BioTab, documents injury causation using evidence from in-depth crash investigations. BioTab focuses on developing injury causation scenarios (ICSs) that document all factors considered essential for an injury to have occurred as well as factors that contributed to the likelihood and/or severity of an injury. The elements of an injury causation scenario are (1) the source of the energy that caused the injury, (2) involved physical components (IPCs) contacted by the occupant that are considered necessary for the injury to have occurred, (3) the body region or regions contacted by each IPC, (4) the internal paths between body regions contacted by IPCs and the injured body region, (5) critical intrusions of vehicle components, and (6) factors that contributed to the likelihood and/or the severity of injury. RESULTS: Advantages of the BioTab method are that it attempts to identify all factors that cause or contribute to clinically significant injuries, allows for coding of scenarios where one injury causes another injury, associates injuries with a source of energy and allows injuries to be associated with sources of energy other than the crash, such as air bag deployment energy, allows for documenting scenarios where an injury was caused by two different body regions contacting two different IPCs, identifies and documents the evidence that supports ICSs and IPCs, assigns confidence levels to ICSs and IPCs based on available evidence, and documents body region and organ/component-level "injury mechanisms" and distinguishes these mechanisms from ICSs. CONCLUSION: The BioTab method provides for methodical and thorough evidenced-based analysis and documentation of injury causation in motor vehicle crashes.