Pelvis-Sacrum-Lumbar Spine Injury Characteristics From Underbody Blast Loading.

INTRODUCTION: Combat-related injuries from improvised explosive devices occur commonly to the lower extremity and spine. As the underbody blast impact loading traverses from the seat to pelvis to spine, energy transfer occurs through deformations of the combined pelvis-sacrum-lumbar spine complex, and the time factor plays a role in injury to any of these components. Previous studies have largely ignored the role of the time variable in injuries, injury mechanisms, and warfighter tolerance. The objective of this study is to relate the time or temporal factor using a multi-component, pelvis-sacrum-lumbar spinal column complex model. MATERIALS AND METHODS: Intact pelvis-sacrum-spine specimens from pre-screened unembalmed human cadavers were prepared by fixing at the superior end of the lumbar spine, pelvis and abdominal contents were simulated, and a weight was added to the cranial end of the fixation to account for torso effective mass. Prepared specimens were placed on the platform of a custom vertical accelerator device and aligned in a seated soldier posture. An accelerometer was attached to the seat platen of the device to record the time duration to peak velocity. Radiographs and computed tomography images were used to document and associate injuries with time duration. RESULTS: The mean age, stature, weight, body mass index, and bone density of 12 male specimens were as follows: 65 ± 11 years, 1.8 ± 0.01 m, 83 ± 13 kg, 27 ± 5.0 kg/m2, and 114 ± 21 mg/cc. They were equally divided into short, medium, and long time durations: 4.8 ± 0.5, 16.3 ± 7.3, and 34.5 ± 7.5 ms. Most severe injuries associated with the short time duration were to pelvis, although they were to spine for the long time duration. CONCLUSIONS: With adequate time for the underbody blast loading to traverse the pelvis-sacrum-spine complex, distal structures are spared while proximal/spine structures sustain severe/unstable injuries. The time factor may have implications in seat and/or seat structure design in future military vehicles to advance warfighter safety.

Temporal corridors of forces and moments, and injuries to pelvis-lumbar spine in vertical impact simulating underbody blast.

Pelvis and lumbar spine fractures occur in falls, motor vehicle crashes, and military combat events. They are attributed to vertical impact from the pelvis to the spine. Although whole-body cadavers were exposed to this vector and injuries were reported, spinal loads were not determined. While previous studies determined injury metrics such as peak forces using isolated pelvis or spine models, they were not conducted using the combined pelvis-spine columns, thereby not accounting for the interaction between the two body regions. Earlier studies did not develop response corridors. The study objectives were to develop temporal corridors of loads at the pelvis and spine and assess clinical fracture patterns using a human cadaver model. Vertical impact loads were delivered at the pelvic end to twelve unembalmed intact pelvis-spine complexes, and pelvis forces and spinal loads (axial, shear and resultant and bending moments) were obtained. Injuries were classified using clinical assessments from post-test computed tomography scans. Spinal injuries were stable in eight and unstable in four specimens. Pelvis injuries included ring fractures in six and unilateral pelvis in three, sacrum fractures in ten, and two specimens did not sustain any injuries to the pelvis or sacrum complex. Data were grouped based on time to peak velocity, and ± one standard deviation corridors about the mean of the biomechanical metrics were developed. Time-history corridors of loads at the pelvis and spine, hitherto not reported in any study, are valuable to assess the biofidelity of anthropomorphic test devices and assist validating finite element models.

Loading rate effect on tradeoff of fractures from pelvis to lumbar spine under axial impact loading.

Objectives: The transmission of impact loading from the seat-to-pelvis-to-lumbar spine in a seated occupant in automotive and military events is a mechanism for fractures to these body regions. While postmortem human subject (PMHS) studies have replicated fractures to the pelvis or lumbar spine using isolated/component models, the role of the time factor that manifests as a loading rate issue on injuries has not been fully investigated in literature. The objective of this study was to explore the hypothesis that short duration pulses fracture the pelvis while longer pulses fracture the spine, and intermediate pulses involve both components.Methods: Unembalmed PMHS thoracolumbar spine-pelvis specimens were fixed at the superior end, and a six-axis load cell was attached. The specimens were mounted on a vertical accelerator, and noninjury and injury tests were conducted by applying short, medium, or long pulses with 5, 15, or 35 ms durations, respectively. Peak axial, shear and resultant forces were obtained. Injuries were documented using posttest x-ray and computed tomography images and scaled using the AIS (2015).Results: The mean age, stature, weight, body mass index, and BMD of twelve specimens were 64.8 ± 11.4 years, 1.8 ± 0.01 m, 83 ± 13 kg, 26.7 ± 5.0 kg/m2, and 114.5 ± 21.3 mg/cc, respectively. For the short, long, and medium duration pulses, the mean resultant forces were 5.6 ± 0.9 kN, 5.9 ± 0.94 kN, and 5.4 ± 1.8 kN, and time durations were 4.8 ± 0.5 ms, 16.3 ± 7.3 ms, and 34.5 ± 7.5 ms, respectively. For the short pulse, pelvis injuries were more severe in 3 out 4 specimens, for the medium pulse, they were distributed between the pelvis and spine, and for the long pulse, spine injuries were more severe in 3 out of 4 specimens.Conclusions: While acknowledging the limitations of the sample size, the results of this study support the hypothesis of the time variable in the tradeoff between pelvis and spine injuries with pulse duration. The tradeoff pattern is attributed to mass recruitment: short pulse biases injuries to pelvis while limiting spinal injuries, and the opposite is true for the longer pulse, thus supporting the hypothesis. It is important to account for the time variable in injury analysis.

Methodology for Evaluation of WIAMan Injury Assessment Reference Curves Using Whole Body Match-Paired Data.

Development of the Warrior Injury Assessment Manikin (WIAMan) capability has included the creation of injury assessment reference curves (IARCs) specific to under-body blast (UBB) loading mechanisms and injuries. The WIAMan IARCs were created from high-rate vertical loading tests of component post-mortem human surrogates (PMHS) and analogous components of the WIAMan anthropomorphic test device (ATD). Validation of the WIAMan IARCs is required prior to the WIAMan ATD being utilized for injury assessment in live-fire vehicle test events. A portion of the validation process involves evaluating the ability of the IARCs to predict injury at the system level (whole body). This study evaluates a methodology to assess the performance of the WIAMan IARCs using match-paired tests of whole body PMHS and the WIAMan ATD. The methodology includes a qualitative analysis designed to identify false-positive and false-negative ATD predictions, as well as a quantitative analysis that utilizes area under the receiver-operating characteristic curve (AROC) and Brier score indices to grade IARC performance. Three WIAMan IARCs were used to exemplify the proposed methodology and results are provided. Attributes of the false-prediction, AROC, and Brier score portions of the methodology are presented, with results indicating the new methodology is thorough and robust in evaluation of IARCs.

Quantifying the Effect of Pelvis Fracture on Lumbar Spine Compression during High-rate Vertical Loading.

Fracture to the lumbo-pelvis region is prevalent in warfighters seated in military vehicles exposed to under-body blast (UBB). Previous high-rate vertical loading experimentation using whole body post-mortem human surrogates (PMHS) indicated that pelvis fracture tends to occur earlier in events and under higher magnitude seat input conditions compared to lumbar spine fracture. The current study hypothesizes that fracture of the pelvis under high-rate vertical loading reduces load transfer to the lumbar spine, thus reducing the potential for spine fracture. PMHS lumbo-pelvis components (L4-pelvis) were tested under high-rate vertical loading and force and acceleration metrics were measured both inferior-to and superior-to the specimen. The ratio of inferior-tosuperior responses was significantly reduced by unstable pelvis fracture for all metrics and a trend of reduced ratio was observed with increased pelvis AIS severity. This study has established that pelvis fracture reduces compression forces at the lumbar spine during high-rate vertical loading, thus reducing the potential for fracture to the lumbar spine. Therefore, pelvis injury potential should be considered when implementing lumbar injury criteria specific to UBB.

Human lumbar spinal column injury criteria from vertical loading at the base: Applications to military environments.

The objective of this study was to determine force-based lumbar spine injury criteria due to vertical impact using Post Mortem Human Surrogate (PMHS) experiments. Mounted personnel in military vehicles sustain loads from the pelvis in combat events such as underbody blast loadings. Forty-three post mortem human subject thoracolumbar spinal columns were obtained, screened for pre-existing trauma, bone mineral densities (BMDs) were determined, pre-test radiological images were taken, fixed at the ends in polymethylmethacrylate, load cells were attached to the ends of the fixation, positioned on custom vertical accelerator device based on a military-seating posture, and impacted at the base. Posttest images were obtained, and gross dissection was done to confirm injuries, classified into single and multilevel groups, groups A and B. Axial and resultant forces at the thoracolumbar (proximal) and lumbosacral (distal) joints were used as response variables to develop lumbar spine injury risk curves using parametric survival analysis. The Brier score metric was used to rank the variables. Age, BMD, column length, and vertebral body and intervertebral disc areas were used as covariates. The optimal metric describing the underlying response to injury was the distal resultant force for group A and proximal axial force for group B specimens. Force-BMD for group A and force-body area for group B were the best combinations. The IRCs with ±95% confidence intervals and quality of risk curves are given in the paper, and they serve as lumbar spine injury criteria. The present human cadaver Injury Risk Curves (IRCs) can be used to conduct matched pair tests to obtain dummy-based injury assessment risk curves/values to predict injury. The present IRCs can be used in human body finite element models. The relationship between covariates and primary forces presented in this study contribute to a better understanding of the role of demographic, geometric, and material factors to impact acceleration loading.

Development of an expert derived ICD-AIS map for serious AIS3+ injury identification.

Objective: The objective of the mapping project was to develop an expert derived map between the International Statistical Classification of Diseases and Related Health Problems (ICD) clinical modifications (CM) and the Abbreviated Injury Scale (AIS) to be able to relate AIS severity to ICD coded data road traffic collision data in EU datasets. The maps were developed to enable the identification of serious AIS3+ injury and provide details of the mapping process for assumptions to be made about injury severity from mass datasets. This article describes in detail the mapping process of the International Classification of Diseases Ninth Revision, Clinical Modification (ICD-9-CM) and the International Classification of Diseases Tenth Revision, Clinical Modification (ICD-10-CM) codes to the Abbreviated Injury Scale 2005, Update 2008 (AIS08) codes to identify injury with an AIS severity of 3 or more (AIS3+ severity) to determine 'serious' (MAIS3+) road traffic injuries.Methods: Over 19,000 ICD codes were mapped from the following injury categories; injury ICD-9-CM (Chapter 17) codes between '800 and 999.9' and injury ICD-10-CM (Chapter 19) 'S' and 'T' prefixed codes were reviewed and mapped to an AIS08 category and then relate the severity to three groups; AIS3+, AIS < =2 and AIS 9 (no-map). The mapping was undertaken by ICD coding experts and certified AIS specialists from Europe, North America, Australia and Canada in face-to-face working groups and subsequent webinars between May 2014 and October 2015. During the process, the business rules were documented to define guidelines for the mapping process and enable inter-rater discrepancies to be resolved.Results: In total 2,504 ICD-9-CM codes were mapped to the AIS, of which 780 (31%) were assigned an AIS3+ severity. For the16,508 ICD-10-CM mapped codes a total of 2,323 (14%) were assigned an AIS3+ severity. Some 17% (n = 426) and 27% (n = 4,485) of ICD-9-CM and ICD-10-CM codes respectively were assigned to AIS9 (no-map) following the mapping process. It was evident there were 'problem' codes that could not be easily mapped to an AIS code to reflect severity. Problem maps affect the specificity of the map and severity when used to translate historical data in large datasets.Conclusions: The Association for the Advancement in Automotive Medicine, AAAM-endorsed expert-derived map offers a unique tool to road safety researchers to establish the number of MAIS3+ serious injuries occurring on the roads. The detailed process offered in this paper will enable researchers to understand the decision making and identify limitations when using the AIS08/ICD map on country-specific data. The results could inform protocols for dealing with problem codes to enable country comparisons of MAIS3+ serious injury rates.

Prominent Injury Types in Vehicle Underbody Blast.

BACKGROUND: To fully understand the injury mechanisms during an underbody blast (UBB) event with military vehicles and develop new testing standards specific to military vehicles, one must understand the injuries sustained by the occupants. METHODS: Injury data from Service Members (SM) involved in UBB theater events that occurred from 2010 to 2014 were analyzed. Analysis included the investigation of prominent skeletal and visceral torso injuries. Results were categorized by killed-in-action (n = 132 SM) and wounded-in-action (n = 1,887 SM). RESULTS: Over 90% (553/606 SM) of casualties in UBB events with Abbreviated Injury Scale (AIS) 2+ injury sustained at least one skeletal fracture, when excluding concussion. The most frequent skeletal injuries from UBB were foot fractures (13% of injuries) for wounded-in-action and tibia/fibula fractures (10% of injuries) for killed-in-action. Only 1% (11/1037 SM) of all casualties with AIS 2+ injuries had visceral torso injuries without also sustaining skeletal fractures. In these few casualties, the coded injuries were likely due to trauma from a loading path other than direct UBB loading. CONCLUSION: Skeletal fractures are the most frequent AIS 2+ injury resulting from UBB events. Visceral torso injuries are infrequent in individuals that survive and they generally occur in conjunction with skeletal injuries.

A Military Case Review Method to Determine and Record the Mechanism of Injury (BioTab) from In-Theater Attacks.

A recent study of all mounted vehicle underbody blast attacks found that 21% of Abbreviated Injury Scale Severity 2+ injuries in the Joint Trauma Analysis and Prevention of Injury in Combat network were injuries to the leg and ankle. To develop effective countermeasure systems for these attacks, the epidemiology and mechanisms of injury from this loading environment need to be quantified. The goal of this study was to develop a military correlate of an existing civilian case review framework, the Crash Injury Research and Engineering Network (CIREN), to consider the differences in military event types and the amount of available vehicle/attack information. Additional data fields were added to the CIREN process to cover military-specific data and "certainty" definitions in the proposed injury hypothesis were modified. To date, six group reviews have been conducted analyzing 253 injuries to the foot/ankle, tibia, femur, pelvis, and lumbar spine from 52 occupants. The familiar format and unclassified nature of the presentations allowed for the involvement of biomechanics experts from multiple disciplines.

Evolution of the Abbreviated Injury Scale: 1990-2015.

OBJECTIVE: Although the Abbreviated Injury Scale (AIS) was initially developed in the mid-1960s for tracking injury in automotive and aircraft crashes, it has grown to become an internationally recognized scoring system for a variety of traumatic injuries. This shift in focus and advances in organized medical care, combined with feedback from field use and outcome analysis, have resulted in several AIS updates and revisions. This article demonstrates how AIS codes and severities have changed over the last 25 years and investigates the effects of those changes. METHODS: Data from each version and update of the AIS dictionary (AIS 1990, AIS 1998, AIS 2005, AIS 2008, and AIS 2015) were analyzed for changes and shifts in injury descriptions, severities, and code counts. RESULTS: The number of AIS codes has increased to improve coding specificity and reliability for a growing number of injury types. There has also been a shift in severities, mainly within the moderate (AIS 2) to severe (AIS 4) range. AIS 1990 was the first version to utilize the 6-digit predot identifier, to add modifiers for pediatric injury, and to substantially expand brain injury codes. AIS 1998 added coding rules and guidelines throughout the dictionary and integrated the Organ Injury Scale scores. The AIS 2005 dictionary added over 400 codes and made significant changes throughout. Fewer changes were made in the AIS 2008 update. AIS 2015 includes descriptions for tissue injuries with loss of soft tissue that do not qualify as amputations, a need identified in military injury analysis. CONCLUSIONS: Each updated version of AIS reflects improving medical care and new advances in understanding, measuring, and documenting injury. AIS changes over time reflect its international and cross-domain utilization for describing injury severity and set the standard for how the world now studies traumatic injury.

Analysis of the Frequency and Mechanism of Injury to Warfighters in the Under-body Blast Environment.

During Operation Iraqi Freedom and Operation Enduring Freedom, improvised explosive devices were used strategically and with increasing frequency. To effectively design countermeasures for this environment, the Department of Defense identified the need for an under-body blast-specific Warrior Injury Assessment Manikin (WIAMan). To help with this design, information on Warfighter injuries in mounted under-body blast attacks was obtained from the Joint Trauma Analysis and Prevention of Injury in Combat program through their Request for Information interface. The events selected were evaluated by Department of the Army personnel to confirm they were representative of the loading environment expected for the WIAMan. A military case review was conducted for all AIS 2+ fractures with supporting radiology. In Warfighters whose injuries were reviewed, 79% had a foot, ankle or leg AIS 2+ fracture. Distal tibia, distal fibula, and calcaneus fractures were the most prevalent. The most common injury mechanisms were bending with probable vehicle contact (leg) and compression (foot). The most severe injuries sustained by Warfighters were to the pelvis, lumbar spine, and thoracic spine. These injuries were attributed to a compressive load from the seat pan that directly loaded the pelvis or created flexion in the lumbar spine. Rare types of injuries included severe abdominal organ injury, severe brain injury, and cervical spine injury. These typically occurred in conjunction with other fractures. Mitigating the frequently observed skeletal injuries using the WIAMan would have substantial long-term benefits for Warfighters.

Development of an expert based ICD-9-CM and ICD-10-CM map to AIS 2005 update 2008.

OBJECTIVE: This article describes how maps were developed from the clinical modifications of the 9th and 10th revisions of the International Classification of Diseases (ICD) to the Abbreviated Injury Scale 2005 Update 2008 (AIS08). The development of the mapping methodology is described, with discussion of the major assumptions used in the process to map ICD codes to AIS severities. There were many intricacies to developing the maps, because the 2 coding systems, ICD and AIS, were developed for different purposes and contain unique classification structures to meet these purposes. METHODS: Experts in ICD and AIS analyzed the rules and coding guidelines of both injury coding schemes to develop rules for mapping ICD injury codes to the AIS08. This involved subject-matter expertise, detailed knowledge of anatomy, and an in-depth understanding of injury terms and definitions as applied in both taxonomies. The official ICD-9-CM and ICD-10-CM versions (injury sections) were mapped to the AIS08 codes and severities, following the rules outlined in each coding manual. The panel of experts was composed of coders certified in ICD and/or AIS from around the world. In the process of developing the map from ICD to AIS, the experts created rules to address issues with the differences in coding guidelines between the 2 schemas and assure a consistent approach to all codes. RESULTS: Over 19,000 ICD codes were analyzed and maps were generated for each code to AIS08 chapters, AIS08 severities, and Injury Severity Score (ISS) body regions. After completion of the maps, 14,101 (74%) of the eligible 19,012 injury-related ICD-9-CM and ICD-10-CM codes were assigned valid AIS08 severity scores between 1 and 6. The remaining 4,911 codes were assigned an AIS08 of 9 (unknown) or were determined to be nonmappable because the ICD description lacked sufficient qualifying information for determining severity according to AIS rules. There were also 15,214 (80%) ICD codes mapped to AIS08 chapter and ISS body region, which allow for ISS calculations for patient data sets. CONCLUSION: This mapping between ICD and AIS provides a comprehensive, expert-designed solution for analysts to bridge the data gap between the injury descriptions provided in hospital codes (ICD-9-CM, ICD-10-CM) and injury severity codes (AIS08). By applying consistent rules from both the ICD and AIS taxonomies, the expert panel created these definitive maps, which are the only ones endorsed by the Association for the Advancement of Automotive Medicine (AAAM). Initial validation upheld the quality of these maps for the estimation of AIS severity, but future work should include verification of these maps for MAIS and ISS estimations with large data sets. These ICD-AIS maps will support data analysis from databases with injury information classified in these 2 different systems and open new doors for the investigation of injury from traumatic events using large injury data sets.

Development of a robust mapping between AIS 2+ and ICD-9 injury codes.

Motor vehicle crashes result in millions of injuries and thousands of deaths each year in the United States. While most crash research datasets use Abbreviated Injury Scale (AIS) codes to identify injuries, most hospital datasets use the International Classification of Diseases, version 9 (ICD-9) codes. The objective of this research was to establish a one-to-one mapping between AIS and ICD-9 codes for use with motor vehicle crash injury research. This paper presents results from investigating different mapping approaches using the most common AIS 2+ injuries from the National Automotive Sampling System-Crashworthiness Data System (NASS-CDS). The mapping approaches were generated from the National Trauma Data Bank (NTDB) (428,637 code pairs), ICDMAP (2500 code pairs), and the Crash Injury Research and Engineering Network (CIREN) (4125 code pairs). Each approach may pair given AIS code with more than one ICD-9 code (mean number of pairs per AIS code: NTDB=211, ICDMAP=7, CIREN=5), and some of the potential pairs are unrelated. The mappings were evaluated using two comparative metrics coupled with qualitative inspection by an expert physician. Based on the number of false mappings and correct pairs, the best mapping was derived from CIREN. AIS and ICD-9 codes in CIREN are both manually coded, leading to more proper mappings between the two. Using the mapping presented herein, data from crash and hospital datasets can be used together to better understand and prevent motor vehicle crash injuries in the future.

Investigation of the safety effects of knee bolster air bag deployment in similar real-world crash comparisons.

OBJECTIVE: The lower extremity is the most frequently injured body region and knee-thigh-hip (KTH) injuries account for half of these injuries. Knee bolster air bags (KBABs) have been incorporated in some vehicles to serve as an additional restraint for the occupant's knees and reduce KTH injuries. To investigate the safety benefits of KBABs, similar frontal crashes with opposing KBAB deployment were selected from the Crash Injury Research and Engineering Network (CIREN) database. METHODS: An 8-point similarity scoring algorithm was used to quantify crash and occupant similarity and select case comparisons. A total of 183 cases without a KBAB were scored for similarity to 9 KBAB cases. These similarity scores were used to select 31 final case comparisons. The effect of KBAB deployment on occupant injury patterns was investigated with a particular focus on KTH injuries. RESULTS: Over half of the occupants exposed to a KBAB sustained no KTH injuries and a reduction in femur fractures was observed in KBAB occupants (P = .036). However, increases in proximal tibia/fibula and foot/ankle fractures were observed in KBAB occupants (P = .022 and .002, respectively). Mildly significant decreases in pelvic fractures and Abbreviated Injury Scale (AIS) 2+ head injuries were observed in the KBAB occupants, supporting the notion that KBABs reduce forward occupant excursion (P = .094 and .055, respectively). Investigation of each case comparison yielded further insight into the reasons for injury pattern differences between cases with opposing KBAB deployment. In addition to KBAB deployment status, differences in occupant factors (age, height, and weight) and crash factors (delta V and belt use) between the cases for a particular comparison could explain variation in injury patterns. CONCLUSIONS: The current study presents a preliminary in-depth qualitative and quantitative assessment of KBAB safety benefits. However, further investigation is recommended to provide conclusive evidence of KBAB effectiveness.

Investigating the effects of side airbag deployment in real-world crashes using crash comparison techniques.

The objective of this study was to investigate side airbag (SAB) deployment in near side crashes and compare injuries and contact points between occupants with and without SAB deployment. Using NASS 2000-2008 and selecting for near side cases, with PDOF ± 20 degrees from 90 or 270, for non-pregnant adult belted occupants, there were 20,253 (weighted) SAB deployments. NASS showed that SABs have been increasing within the fleet, comprising 2% of airbags in 2000 and increasing to 33% of airbags in 2008. To investigate deployed SABs, we developed a three-step methology to pair CIREN cases to study the effects of deployment on occupant outcome. The first step involved extracting near side impacts from CIREN with adult, non-pregnant occupants seated in row 1 (drivers or right front passengers). In the second step, each case was quantitatively compared to FMVSS 214 barrier test standards using a 6 point similarity scoring system. Cases scoring at least 3 points were then qualitatively analyzed and 33 pairs of cases of the same vehicle make/model but opposite SAB status were chosen. Occupants with deployed SAB had reduced occurrences and severity of head and face, neck and cervical spine, and thoracic injuries and fewer injurious contacts to side components including the door, a-pillar, and window sill. SAB deployment was statistically significant for reducing occupant MAIS and ISS and thorax airbags were statistically significant for reducing thoracic and neck/cervical spine injury severity. The average ISS with SAB deployment was 21, while the average ISS of those without was 33. This study establishes methods for performing comparisons between CIREN cases based on regulatory conditions and shows injury reduction in key body regions with SAB deployment.

Pediatric occupants, restraint use, and injuries in motor vehicle crashes - biomed 2011.

Pediatric occupants are vulnerable in motor vehicle crashes (MVCs), and alternative restraints have been developed for their protection. This study sought to characterize injuries in MVCs for pediatric occupants and to identify scenarios that may benefit from enhanced vehicle safety. Using the NASS-CDS database (2000-2008), pediatric occupants (< 19 yr old) were characterized by their age and injuries to look at national averages in MVCs. There were over 14 million pediatric injuries and non-injured occupants in weighted NASS-CDS (out of over 70 million total). Of these pediatric cases, 60% sustained injuries, which was comparable to the percentage of all occupants injured (65%). Six percent of NASS-CDS pediatric occupants had AIS 2+ injuries, which is the injury inclusion criteria for CIREN pediatric cases. CIREN was used to investigate pediatric occupants and injuries resulting from incorrect positioning and restraints according to NHTSA suggestions. Results indicated that many injured pediatric occupants were not properly restrained, with over 100 in the front row of the vehicle under 13 years of age. There were also over 200 CIREN pediatric occupants under 4’ 9” that were not seated in a child safety seat (CSS). The most frequently injured body region was the face, followed by the head and lower extremity. Eighty-six percent of head injuries and 82% of spinal injuries were AIS 2+. This study supports prior findings that demonstrate a need for enhanced public awareness for proper CSS use to reduce pediatric injuries in the future.

Utilizing computed tomography scans for analysis of motorcycle helmets in real-world crashes - biomed 2011.

In 2008, there were more than 5,000 motorcycle crash fatalities in the United States. Many states have motorcycle helmet laws that are meant to protect riders during a crash. After recruiting motorcycle occupants injured in crashes, a protocol was established to scan three different types of motorcycle helmets commonly worn (cap, ¾ shield, and full face shield) using a computed tomography (CT) scanner. The protocol developed was for a GE 64 slice PET/CT Discovery VCT scanner with axial images from anterior to posterior helmet acquired in helical mode. It had 512x512 resolution and the full face and ¾ face shield helmets were scanned with greater voxels in the axial plane compared to the skull cap helmets. New helmets were scanned as exemplary images for comparison with helmets involved in motorcycle crashes. After CT scans were gathered, three-dimensional reconstructions were made to visualize scratches and impacts to the exterior of the helmets. Initial work was also conducted in analyzing interior components, and a trend was seen in decreased thickness between the interior foam and shell with sides of the exterior helmet thought to have contacted roadside barriers or the ground during motorcycle crashes. These helmet analysis methods have been established, and will be used to investigate multiple motorcycle crashes in conjunction with occupant injuries and direct head impacts to improve helmet design and the understanding of head injuries. This work also establishes the basis for development of finite element models of three of the most common helmet types.

Biomechanical modeling of eye trauma for different orbit anthropometries.

In military, automotive, and sporting safety, there is concern over eye protection and the effects of facial anthropometry differences on risk of eye injury. The objective of this study is to investigate differences in orbital geometry and analyze their effect on eye impact injury. Clinical measurements of the orbital aperture, brow protrusion angle, eye protrusion, and the eye location within the orbit were used to develop a matrix of simulations. A finite element (FE) model of the orbit was developed from a computed tomography (CT) scan of an average male and transformed to model 27 different anthropometries. Impacts were modeled using an eye model incorporating lagrangian-eulerian fluid flow for the eye, representing a full eye for evaluation of omnidirectional impact and interaction with the orbit. Computational simulations of a Little League (CD25) baseball impact at 30.1m/s were conducted to assess the effect of orbit anthropometry on eye injury metrics. Parameters measured include stress and strain in the corneoscleral shell, internal dynamic eye pressure, and contact forces between the orbit, eye, and baseball. The location of peak stresses and strains was also assessed. Main effects and interaction effects identified in the statistical analysis illustrate the complex relationship between the anthropometric variation and eye response. The results of the study showed that the eye is more protected from impact with smaller orbital apertures, more brow protrusion, and less eye protrusion, provided that the orbital aperture is large enough to deter contact of the eye with the orbit.