Position of the abdominal seat belt sign and its predictive utility for abdominal trauma.

OBJECTIVE: In a motor vehicle crash, compressive forces from the lap component of the seat belt may produce an abdominal abrasion/contusion known as the 'seat belt sign', and is associated with abdominal and lumbar injuries. Previous research has not taken into account the position of this sign in relation to the anterior superior iliac spine (ASIS). Our aim was to demonstrate an association between the seat belt sign position in relation to ASIS and the presence of abdominal/lumbar injury. METHODS: A mixed prospective and retrospective observational study of patients involved in a motor vehicle crash was conducted. The presence of a seat belt sign was recorded as above ASIS, at/below ASIS, or none. Injury data were extracted from discharge summaries, radiology reports and operation reports. Proportions of patients with injuries were compared across the three groups. RESULTS: Four hundred and sixty-four participants were enrolled. For participants with a seat belt sign above ASIS, compared to those with no seat belt sign, the positive likelihood ratio for a seat belt related injury was 4.2 (95% CI 2.6-6.8). When the seat belt sign was at/below the level of ASIS the positive likelihood ratio was 1.5 (95% CI 0.4-5.7). CONCLUSION: The seat belt sign is associated with abdominal and lumbar injury; however, the location is important. This association is strong when the seat belt sign is above ASIS, but when the sign is at/below the ASIS the injury rate is similar to participants with no seat belt sign. Routine imaging of the abdomen may be appropriate only for those with a seat belt sign above ASIS.

Field effectiveness of two restraint systems: the 3-point manual belt versus the 2-point motorized-shoulder/manual lap belt.

The research question addressed in this paper is whether or not occupant death, injury, and ejection outcomes differ between vehicles equipped with 3-point manual belts versus 2-point motorized-shoulder/manual-lap (motorized/manual) belt systems. Census crash data sets for the states of Washington and Texas, and the Fatal Accident Reporting System (FARS) were subset to provide data on front-outboard occupants of Ford Escorts involved in crashes in calendar years 1981-1991. Logistic regression analyses showed that occupants of vehicles equipped with the motorized/manual system experienced 11.7% to 26.4% fewer K- or A-level injuries than occupants of vehicles equipped with the 3-point system. Similar analyses of FARS data showed lower ejection rates for occupants of vehicles with the motorized/manual system in both rollover and nonrollover crashes. The installation of the motorized/manual system provided a substantial safety benefit over the manual 3-point system in the time periods examined.

Sensitivity of THOR and Hybrid III dummy lower neck loads to belt systems in frontal impact.

OBJECTIVES: To determine head-neck biomechanics with a focus on lower neck injury metrics in frontal impact. The mid- and large-size Hybrid III dummies and the mid-size Test device for Human Occupant Restraint (THOR) were positioned on a buck. Tests were conducted at low, medium, and high (3.3, 6.7, and 15.7 m/s) change in velocities using 3 restraint types: normal 3-point belt with no pretension (type A), 10-cm pretension (type B), and 200 N pretension (type C). Repeat tests were conducted. Measured vertical and shear forces and sagittal bending moments were evaluated at the upper and lower regions of the neck to different types of belt systems and at different change in velocities. Peak values normalized with respect to the belt type A were used in the comparative analysis. Metrics transformed to the occipital condyles and T1 were also evaluated. RESULTS: All dummies showed good repeatability. Peak measured and transformed upper and lower neck moments were greatest in the large-size dummy. The mid-size Hybrid III dummy responded with greater forces and moments than the THOR. Regardless of dummy type, anthropometry, and velocity, peak lower neck moments were more sensitive to belt types than peak lower neck forces. A similar pattern was apparent for upper neck data. Moments in the THOR were more sensitive than moments in the mid-size Hybrid III dummy. CONCLUSIONS: This study offers quantitative generic restraint-based data and addresses response differences between dummies and dummies of the same family. Because of increased sensitivity to belt types at the upper and lower necks for both forces and moments, the THOR appears to be an improvement to better assess injury potential to rear seat occupants wherein frontal impact air bags do not exist.

Pediatric motor vehicle related injuries in the Navajo Nation: the impact of the 1988 child occupant restraint laws.

BACKGROUND: Navajo motor vehicle mortality is the highest among the 12 Indian Health Service (IHS) administrative areas. In July 1988, the Navajo Nation enacted a primary enforcement safety belt use and a child restraint law. OBJECTIVE: Assess the impact of the laws on the rate and severity of pediatric (0-19 years) motor vehicle injury resulting in hospitalizations in the Navajo Nation. METHODS: Hospitalizations associated with motor vehicle related injury discharges were identified by International Classification of Diseases, 9th revision, CM E codes, 810-825 (.0,.1) from the Navajo IHS hospital discharge database. Age specific rates for the period before the law, 1983-88, were compared with those after enactment and enforcement, 1991-95. Severity of injury, measured by the abbreviated injury scale (AIS) score and new injury severity score (NISS), was determined with ICDMAP-90 software. Wilcoxon rank sum and chi(2) tests were used for analysis. RESULTS: Discharge rates (SE) for motor vehicle injury (per 100 000) decreased significantly in all age groups: 0-4 years (62 (7) to 28 (4)), 5-11 years (55.3 (6) to 26 (4)), and 15-19 years (139 (14) to 68 (7)); p=0.0001. In children 0-4 years, the median AIS score decreased from 1.5 (1,3) (25th, 75th centile) to 1 (1,2), p=0.06, and the median NISS decreased from 3.5 (1,9) to 2 (1,5), p=0.07. The proportion of children with NISS scores >4 decreased significantly for the 0-4 year age group (p=0.03). CONCLUSIONS: Concurrent with enactment of the Navajo Nation occupant and child restraint laws there was a reduction in the rate of motor vehicle related hospital discharges for children. Severity of injury declined in very young Navajo children. The effect of enactment and enforcement of this Native American child occupant restraint law may serve as an example of an effective injury control effort directed at Native American children.

Static analysis of harness fit inforward-facing child restraints

O presente estudo tem a finalidade de avaliar o sistema de proteção dos dispositivos de retenção infantil, tais como a passagem do cinto de cinco pontos, referentes às tiras do torso e abdominais, e também avaliar a localização de componentes de proteção. Três modelos de dispositivos foram analisados em laboratório simulador no banco traseiro de veículo usando um dummy de três anos da família Hybrid III. A coleta de dados foi feita por meio de marcas predeterminadas no dummy e nos dispositivos e registradas tridimensionalmente por um equipamento digitalizador de pontos em 3D (FaroArm). Para isso, o dummy foi instalado nos assentos após sua fixação no carro seguindo os padrões da norma norte-americana nº 213, da Federal Motor Vehicle Safety Standard – FMVSS “Child Restraint Systems” (NHTSA, 2005). Os resultados mostraram uma grande variação no posicionamento dos componentes de proteção entre os modelos analisados. O cinto do torso apresentou diferenças em sua passagem no tórax superior conforme a altura de regulagem. A posição do cinto abdominal também variou entre os modelos, sendo observada a passagem do mesmo na região do abdômen ao invés de locais mais rígidos, como os ossos da pélvis. Além disso, a localização do componente lateral de proteção da cabeça sofreu grande variação em relação ao centro de gravidade de cabeça do dummy, indicando que, em alguns casos, a cabeça da criança pode não ser protegida lateralmente por se deslocar amplamente no caso de impacto lateral do carro, o que provocaria lesão. Os resultados deste trabalho sugerem que o design de assentos infantis ainda apresenta falhas quanto ao posicionamento dos componentes de proteção em relação às características anatômicas da criança, considerando a ampla faixa etária para que são fabricados.

A material suitable for craniofacial reconstruction must be easy to implant, have the appropriate shape, have the strength and deformation similar to the original bone, be eventually substitutedfor natural bone, be widely available and present affordable costs. As such as material, with all theses characteristics is still not available, it is important to search for new materials, new compositions and new design. Different biomaterials are used nowadays for craniofacial reconstruction surgeries, each one presenting its advantages and limitations. Among these materials are the titanium, the poli(methilmetacrilate) and the calcium phosphate cements. Titanium presents hard conformation; poli(methilmetacrilate)’spolymerization reaction is exothermic, which may cause necrosis of the adjacent tissues; calcium phosphate cement is brittle, an usual characteristic of ceramic materials. In this way, this study evaluated different materials used for craniofacial reconstruction and its mechanical properties when submitted to bending test, such as poli(methilmetacrilate), calcium phosphate cement and calcium phosphate cement reinforced with titanium. It was verified the improvement in the mechanical properties of the calcium phosphatecement when reinforced with titanium mesh. In addition, this study presents a method for design and manufacturing of customized craniofacial implants using calcium phosphate cement reinforced with titanium mesh, validated through four cases of craniofacial reconstruction surgery indication.