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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.

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.

Injury statistics show that lower extremity injuries follow second to head trauma in motor vehicle crashes. Fractures to the ankle/foot make up approximately 35% of all lower extremity injuries in motor vehicle crashes. Previous studies have shown that toe pan intrusion is one of the main causes of foot and ankle fractures in motor vehicle crashes (MVC). This study investigates injury mechanisms of malleolar fractures involving occupants enrolled in the Wake Forest University Crash Injury Research and Engineering Network (WFU CIREN) center. By narrowing cases to frontal impacts (+/- 20 degrees principal direction of force) with the case occupant as the driver with lower leg fractures, 16 cases are identified and investigated for trends in lower leg injury. Of these fractures, 81% of the occupants have a body mass index (BMI) greater than 25 kg/m2, with an average BMI of 32 kg/m2, which is obese. For occupants with malleolar fractures the average delta V is 44.1 kph (27.4 mph) and the average intrusion is 9.6 cm. Using radiology images of each ankle fracture in conjunction with interior vehicle evidence, injury mechanisms for malleolar fracture types are identified using the Lauge-Hansen and Weber classifications. The most common malleolar fracture type was supination-exorotation with a Weber B fibular fracture (4 cases). There were also four drivers that sustained trimalleolar fractures. Drivers sustaining lower leg fractures other than malleolar fractures had an average BMI of 30 kg/m2, an average delta V of 39.6 kph (24.6 mph), and average toe pan intrusion of 12.0 cm. Results show that the malleolar fracture and other lower leg fracture datasets have similar average delta Vs and toe pan intrusions, but the average BMI is slightly higher in the malleolar fracture group. These preliminary data suggest that occupants with increased BMI may be more susceptible to ankle fractures in frontal crashes, particularly malleolar fractures. The trends presented in this research will be used for the development of future studies for the enhancement of vehicle safety.

Eye trauma is an increasing problem, especially in the military, due to blunt force trauma. One way to mitigate eye injury is to wear protective eye equipment. An essential part of creating protective eye equipment is prototype testing in controlled eye trauma simulations. In addition, the protective equipment must fit properly and thus incorporate variance, specifically among gender, ethnicity, and age. It is beneficial to create standard orbits classified according to the aforementioned categories of gender, ethnicity, and age. Using head CT scans from grossly normal subjects, segmentation of the ocular orbit was performed. This segmented mask was then imported into a three dimensional printing software. Orbits from different sizes, ages, genders, and races were created and printed using a ZCorp printer. A mold negative was then created from the 3D printed orbits using InstaMold. After the mold was cured and removed from the printed orbit, reproductions of the eye orbit were created from this negative. These methods will be used in the future to make molds for many different ages, genders, and races in order to create accurate models of the eye orbit. These can then be used to develop impact tests by incorporating eye samples into these sockets of uniform shape. These methods for creating surrogate eye sockets will reduce the need for cadaver eye sockets and will increase the number of tests that can be performed. By creating accurate models, more accurate representations of eye trauma and its prevention can be investigated.

Motor vehicle accidents are the leading cause of death of people between one and thirty-four years of age in the U.S., and head trauma is a significant lethal injury in such cases. During a motor vehicle crash, the head often experiences blunt force trauma from impacts with seat backs, steering wheels, windows, and dashes. The resulting injuries can cause skull fractures, concussions, bleeding and swelling of the brain. Crash test dummies and finite element models are often used to study the nature and likelihood of injury during a crash, but these are currently based on scaled versions of a standard, 50th percentile male. This approach fails to accurately capture the size and shape variation in even the adult population, but may be especially inappropriate for modeling pediatric head injuries where, for instance, infants have fontanelles and reduced bone structure. In this presentation, an approach for modification of a finite element model of the human head based on 50th percentile male dimensions and representing the skull, brain, dura/CSF layer, and Falx Celebri, that will incorporate the anatomical and nonlinear morphological changes observed in pediatric skulls during ontogeny. Using 96 CT scans of normal pediatric skulls, landmark coordinate points are identified to map the changes in skull shape and size as aging occurs. The pediatric skull changes rapidly in size and shape during the first two years of age. Using this information, a pediatric finite element head model will be created, using parametric mesh generation software, to measure head injury in children in a motor vehicle crash.

To fully understand the effects of aging on the integrity of the normal skeleton, detailed geometric models are needed to complement material property data. The purpose of this research is to develop a predictive model for age-related changes in rib-cage geometry using the generalized Procrustes approach, an advanced method of shape analysis. This predictive model is coupled with the finite element method to isolate the effects age-related size and shape change have on the structural response of the rib cage. Using a relatively small sample set (n = 12), trends in the age-related size and shape change of the human thorax consistent with clinical observations are identified. Finite element models constructed from landmark datasets generated via the generalized Procrustes approach demonstrate a decrease with age in the energy absorbing capacity of the thorax during a blunt impact.