The purpose of this study was to use detailed medical information to evaluate thoracic injuries in elderly patients in real world frontal crashes. In this study, we used analytic morphomics to predict the effect of torso geometry on rib fracture, a major source of injury for the elderly. Analytic morphomics extracts body features from computed tomography (CT) scans of patients in a semi-automated fashion. Thoracic injuries were examined in front row occupants involved in frontal crashes from the International Center for Automotive Medicine (ICAM) database. Among these occupants, two age groups (age < 60 yr. [Nonelderly] and age ≥ 60 yr. [Elderly]) who suffered severe thoracic injury were analyzed. Regression analyses were conducted to investigate injury outcomes using variables for vehicle, demographics, and morphomics. Compared to the nonelderly group, the elderly group sustained more rib fractures. Logistic regression models were fitted with different configurations of variables predictive of the Maximum Abbreviated Injury Scale of the thoracic region (MAISthx 3+). The performance of models was assessed using area under the receiver operating characteristic curve (AUC). AUC is a widely-used “rating” method to…

Liver injuries can be significant in vehicle crashes. In this study, the liver anatomy was quantified in both adult and pediatric populations as a function of gender and age. Five anatomical liver measurements were determined using CT scans of 260 normal livers. These measurements include the area and volume, and the length, width, and girth of the liver (IRB HUM00041441). To characterize geometrical shape, an inscribed sphere and circumscribed ellipsoid were fitted on the measurements. In the pediatric population the liver area and volume continuously increased with age. When normalized by patient weight, volume measurements show a decrease in volume with age, suggesting that the liver occupies a smaller proportion of the body with age. In the adult population, liver measurements varied with gender. The superior and inferior locations of the liver were also recorded with respect to the spine. The lower portion was at the L3 in small children and at L2 as children approached puberty. It stayed in that area through the 60+ group, offering more ribcage protection.Liver injury patterns were also assessed…

The human body changes as it becomes older. The automotive safety community has been interested in understanding the effect of aging on restraint performance. Recent research has been focused on assessing the structural and material changes associated with age. In this study, structural tissue distribution was determined using the computed tomography (CT) scan data of more than 19,000 patients, aged 16 and up. The data consisted of subcutaneous fat cross-sectional area, visceral fat cross-sectional area, and trabecular bone density taken at each vertebral level. The data was quantified as a function of five age groups with the youngest group defined as 16-29 years old and the oldest group as 75 and up. An additional analysis stratified on gender was carried out.Overall, visceral fat increased with age. Compared to the 16-29 group, the visceral fat measured at the L1 level was 1.97 in the 30-44 group, 2.55 in the 45-59 group, 3.33 in the 60-74 group and 3.21 times greater in the 75+ group. Subcutaneous fat also increased with age up to the 60-74-year-old group. The…

Different vertebral facet angles in pediatric versus adult necks may explain their disparate biomechanical tolerance and motion under physical loading. We analyzed CT scans of the neck using novel semi-automated image processing software algorithms to characterize the morphology of each cervical vertebra, including precise measurement of facet angle relative to other vertebral landmarks. We observe clear and very significant changes in facet angle with aging for C2 through C7. These findings are useful, when analyzed in conjunction with vehicle crash and injury data, to identify occupant specific factors that may contribute to motor vehicle crash injury tolerance in live subjects.

The size and shape of the acetabulum and of the femoral head influence the injury tolerance of the hip joint. The aim of this study is to quantify changes in acetabular cup geometry that occur with age, gender, height, and weight. Anonymized computed tomography (CT) scans of 1,150 individuals 16+ years of age, both with and without hip trauma, were used to describe the acetabular rim with 100 equally spaced points. Bilateral measurements were taken on uninjured patients, while only the uninjured side was valuated in those with hip trauma. Multinomial logistic regression found that after controlling for age, height, weight, and gender, each 1 degree decrease in acetabular anteversion angle (AAA) corresponded to an 8 percent increase in fracture likelihood (p≺0.001). Age, weight, and gender were found to influence anteversion angle significantly, with each 10 years in age increasing AAA by 1.07 degrees, each 10 kg of weight decreasing AAA by 0.45 degrees, and being female resulting in 1.42 degrees greater AAA than males. Height was not found to relate significantly to AAA after…

This paper reports on a study that examines the effect of shoulder belt load limiters and pretensioners as well as crash and occupant factors that influence upper torso harm in real-world frontal crashes. Cases from the University of Michigan International Center for Automotive Medicine (ICAM) database were analyzed. Additional information was used from other databases including the National Highway Traffic Safety Administration (NHTSA) New Car Assessment Program (NCAP), the Insurance Institute for Highway Safety (IIHS), the National Automotive Sampling System - Crashworthiness Data System (NASS-CDS), and patient data available from the University of Michigan Trauma Center. The ICAM database is comprised of information from real-world crashes in which occupants were seriously injured and required treatment at a Level 1 Trauma Center. Cases from the database were included in this study if they met the following criteria: (a) the primary collision involved a frontal type crash and; (b) case occupants were seated in front outboard positions, restrained by 3-point safety belts and deployed frontal airbags.One hundred thirty-three (133) case occupants who sustained nearly 1,800 injuries were…

Side impact field crashes from the University of Michigan Crash Injury Research and Engineering Network (UM CIREN) database were studied in detail. These cases involved seriously injured occupants that spanned 1997 - 2006 model year vehicles. Specific injury risks are not presented because the database used was populated only with occupants requiring treatment at a Level 1 Trauma Center.This study analyzes side impact collisions for AIS ≥ 3 injury patterns in crash configuration, injury contact locations, gender and by age. Field crashes were also categorized into those that represent existing standard side impact laboratory test methods.Over half of the cases were identified as collisions into the passenger compartment with occupants seated on the near side of the vehicle closest to the impact, which is consistent with current standard laboratory tests. The next two largest categories involved either far-side occupants or impacts primarily centered onto the engine compartment. The most commonly injured body regions in the above categories were the head, thorax and lower extremity. Females had the highest proportion of pelvic injuries. While bone density…

Standard medical chest and abdomen computed tomography (CT) scans were used to take detailed measurements of human rib geometry and material properties from a wide range of patients. Geometric quantities included rib cross-sectional area, height, width, and aspect ratio. Material-based quantities included rib cross-sectional average density, and measurements of inner and outer cortical bone thickness and cortical bone density. We found significant local and regional variation both within and between individuals. Proposals are made for the use of these measurements to inform and improve human finite element chest models, allowing them to more accurately represent the human ribcage.

Development of human body finite element models capable of predicting crash injuries has been hampered by the lack of injury data that is sufficiently precise and detailed. Even CIREN data, the most medically detailed crash injury data currently in existence, is insufficient for model development. We therefore developed a novel protocol to identify and measure precise 3-dimensional locations of rib fractures present in CT scans from the CIREN population of car crash occupants. This protocol was used to develop a database associating fractures in their spatial locations with rib framework curves that were defined for each ribcage using a semi-automatic image processing system. Results form this database include a heat map of fracture locations over a representative human rib cage. This heat map is presented from a series of different crash configurations, showing the precise trends in rib fracture locations and how they change with occupant position, crash direction and severity, and with the different restraint types used. Our new system captures the precise spatial location of injuries in a format that can be directly…

Standard medical chest and abdominal computed tomography (CT) scans of 46 subjects were analyzed to characterize aspects of human ribcage geometry and bone density. A semi-automatic algorithm was developed to define framework curves for individual ribs. Measurements of this framework were taken to record anthropometric properties of the ribcage such as overall ribcage dimensions and individual rib lengths and angles. Furthermore, the ribcage framework was used to explore the voxel space of the CT images, recording local rib bone cross-sectional density properties. Proposals are made for the use of these measurement techniques to inform and improve human finite element (FE) chest models in terms of global geometry, material properties, and individuality.