Biomedical subjects

D C Viano

Publications and source records attributed to D C Viano.

At least 19 recordsLinked to original sources

PubMed1996

Foot-ankle injuries: influence of crash location, seating position and age.

Foot-ankle injuries have increased in relative importance in recent years. As a basis for future countermeasures, an epidemiology study has been undertaken using Swedish accident data from Folksam Insurance. The database consists of 805 foot-ankle injuries out of 57,949 car occupant injuries reported from 1985 to 1991. The influence of crash location, seating position and occupant age is determined for the frequency, incidence and rate of foot-ankle injury in car crashes. Frontal car crashes produce 76% of the AIS 2-3 foot-ankle injuries with 13% in side impacts and 8% in roll-overs. The rate of AIS 2-3 foot-ankle injury is 24.7 per 1000 occupants injured in all crash locations and is similar irrespective of seating positions. Ankle fractures and sprains both occur at an incidence of 3.7 per 1000 injuries, followed by malleolus fractures at 2.7 and midtarsal fractures at 2.4. The foot-ankle injury incidence and rate are significantly greater (p < 0.01) in near oblique-frontal crashes than for 12 o'clock frontals. For drivers in 11 o'clock and front passengers in 12 o'clock, the incidence is 27.8 per 1000 injuries as compared to 17.5 for drivers and front passengers in 12 o'clock crashes. Occupant age is not as significant as seating position and crash location; however, there are higher incidences for rear occupants > or = 60 years old in oblique frontal crashes. Using the new AAAM Impairment Injury Scale (IIS), 48% of the foot-ankle injuries are rated with residual impairment IIS 1-2. The incidence in near-seated occupants is 1.5 times greater in oblique frontal crashes than in frontals. The incidence for IIS 1-2 impairment in near oblique-frontal crashes is 12.8 per 1000 occupant injuries as compared to 8.3 in frontal crashes.

Abbreviated Injury Scale↗

PubMed1996

Headrest position during normal driving: implication to neck injury risk in rear crashes.

The gap and relative height of headrest behind drivers were determined for 1915 vehicles approaching an intersection on a two lane road. Vehicle type and headrest adjustment were also evaluated using film of normal driving taken by the Insurance Institute for Highway Safety. Only 10% of drivers had headrests in the most favorable position to prevent neck extension during a rearend crash. 73% of cars had adjustable headrests, but only a quarter were placed in the up position. 83% of the adjustable headrests could have been raised to better protect the driver. Hyge sled tests were run to determine biomechanical responses for the various conditions observed in normal driving. This included three headrest heights and three gaps behind the head. Neck extension from the Hybrid III dummy was normalized to the response for a high, close headrest, and injury risk was assumed to be proportional to neck extension. The current driving situation has a relative injury risk of 3.4 in rearend crashes, compared to 1.0 for the favorable condition. If all adjustable headrests were placed in the up position, the relative risk would be lowered to 2.4, a 28.3% reduction in whiplash injury risk. Public education and vehicle design should address the importance of proper headrest placement for driving safety.

Accidents, Traffic↗

PubMed1995

Restraint effectiveness, availability and use in fatal crashes: implications to injury control.

The effectiveness and benefits of occupant restraint systems are compared by seating position in motor vehicles. While safety belts are 42% effective in preventing fatalities, the addition of the driver side airbag provides a 12% increase in effectiveness. The implications of safety belt use and airbag availability over the next decade are considered for fatal injury prevention. The analysis includes theoretical relationships and forecasts fatality prevention as lap-shoulder belt use increases and airbags phase into the vehicle fleet.

Accidents, Traffic↗

PubMed1995

Humanitarian benefits of cadaver research on injury prevention.

This paper discusses the value of human cadaveric subjects in injury biomechanics research. Published data were used to estimate the number of cadavers used in the past 30 years and to show that, as a benefit to society, over 60 lives were saved and countless injuries prevented for each cadaver used in the development and validation of safety improvements. Ethical and religious concerns regarding the use of cadavers are also addressed. Because of the substantial humanitarian value of cadaver research and the lack of suitable specimens, it is proposed that cadaver resources be pooled and that institutions with surplus specimens supply the few cadaver testing laboratories with specimens each year. This approach will enable further development of safety systems and facilitate achieving the national goals for injury control.

Accidents, Traffic↗

PubMed1994

Computing body segment trajectories in the Hybrid III dummy using linear accelerometer data.

An analytical method was developed and tested using several mini-sled and Hyge sled tests to calculate the planar trajectory of a Hybrid III dummy head. Aimed at expediting the Hybrid III test analyses, it may provide an opportunity for cost savings through reduced hardware and manpower on film analyses. Transformation from the moving coordinate to the laboratory coordinate is based on the angular positions integrated from the derived angular accelerations. Gravitational correction of the linear accelerometers was found to be insignificant. The computed head trajectories were compared to the ones obtained from the high speed film images. Accuracy of the calculated head trajectory relies heavily on the accuracy of the computed angular acceleration. Strain-gaged accelerometers are not dependable at all times during an impact and an ill-behaved signal for a very short period may create a significant drift in computed displacement due to double integrations. Accuracy of the currently available accelerometers is not high enough for an angular displacement calculation. A new generation of accelerometers with higher accuracy, or an angular velocity sensor may provide more accurate angular displacement for trajectory analyses. The redundancy of the in-line accelerations helps improve the isolation of erroneous outputs and improve accuracy of the procedure.

Acceleration↗

PubMed1994

Comparison of arm up and down in side impacts with BioSID and different armrests.

BioSID dummy tests were run with the arm down at the side during loading of different armrests in simulated side impact crashes. The Hyge sled tests duplicated previous studies of BioSID with the arm up, SID, and animals. When the BioSID arm is against the side, the arm extends from the shoulder to the bottom of the third rib and has a steel shank covered by foam and vinyl. Loading through the arm transfers force to the three chest ribs and shoulder. In comparison, direct armrest loading of the chest or abdomen primarily involves a single rib and substantial rib deflection, when the armrest crush-force exceeds the strength of the rib. The Viscous response in BioSID showed the greatest difference of all criteria for the arm up or down. The response of the third rib correlated with injury risks determined from animal tests using the different armrest designs in a simulated high position. While injury data are not available for the arm at the side or for the armrest in the low position, the STIFF armrest may cause injury when the arm is not at the side and the armrest loads the liver and spleen. Rib deflection in BioSID showed the protrusion of the STIFF armrest into the abdominal region in both arm positions, because the loading was below the arm even in the down position. However, the arm extends laterally so it involves the upper ribs earlier than in the arm-up condition where more space is available.(ABSTRACT TRUNCATED AT 250 WORDS)

Accidents, Traffic↗

PubMed1993

Mechanism of injury from air bag deployment loads.

Loadings induced by deploying currently representative air bags were studied with driver surrogates (anesthetized swine) leaning against the system during inflation. Torso injury mechanisms were studied in a physiologic model, supported against a static steering wheel-mounted air bag system. Severe and extensive chest and abdominal injuries to the swine were observed in the tests. Loading caused by air bag deployment can occur in either of two phases. The first phase represents the initial punch out of the bag from the module; the second phase represents the membrane force of the inflating bag. Statistical analysis indicated that punch out induced injury because of the high rate of loading to the surrogate body region in direct contact with the air bag module. Membrane forces induced injury by high compression over a larger area. Punch-out loading might be reduced by allowing the bag to escape from other parts of the container not in contact with the driver during deployment. Loading by the inflating bag might be reduced by using a compliant steering system to support the module. The amount and rate of generated gas had only marginal effect on the cumulative injury. Even an inflator with inadequate gas output to protect a properly seated occupant had sufficient energy to induce severe injuries in a surrogate in contact with the inflating module. Analysis of the field relevance of the results must consider not only the injury potential given that a driver is in direct contact with the air bag module at the time of deployment, but also the expected field frequency of such an event. Analysis of the field relevance of the results must also consider the correlation of the laboratory test environment with real-world exposure.

Abdominal Injuries↗

PubMed1993

Biomechanics of abdominal injuries by armrest loading.

Anesthetized pigs were exposed to impact against a padded side interior that included an armrest with either a SOFT or STIFF crush characteristic. The purpose was to assess liver and spleen injury under specific impact conditions. The STIFF armrest resulted in severe abdominal and thoracic injury in five side-impact animal tests. Injuries of the liver and spleen included deep lacerations, tears of major hepatic arteries and veins, and serious hemoperitoneum. The injuries averaged AIS = 4. In contrast, five animals exposed to the SOFT armrest design experienced injuries of lower severity than any animal in the STIFF armrest exposures (p < 0.005). The average injury was AIS = 2. The STIFF armrest protruded into the abdomen and showed little sign of deformation with abdominal loading. This situation is consistent with the occurrence of lacerations at hepatic junctions and between lobes, and displaced rib fractures in several cases. The SOFT armrests crushed fully in each test, indicating that abdominal compression was lower and was limited by armrest deformation.

Abdominal Injuries↗

PubMed1991

Live fire testing: assessing blunt impact and acceleration injury vulnerabilities.

The joint services live fire testing program is a vulnerability and lethality assessment program in which realistic munitions are fired at combat-loaded U.S. systems. The program provides direct visual observation of potential damage caused by weapons effects on targets and crew under combat conditions and provides data assisting subjective engineering judgments on system vulnerabilities with the rapid advance in munitions technologies. Congress and the Department of Defense recognize the need to improve the scientific capability to estimate the effects of weapon systems on humans and the need to produce precise estimates of potential casualties in combat situations. This study evaluates the current U.S. capability to make credible crew casualty assessments of blunt impact and acceleration injury in live fire tests. It summarizes the results of a 2-day workshop hosted by the Department of Defense to identify potential live fire threats, mechanisms of injury and performance criteria, available data bases, requirements for instrumentation and analysis, use of crew casualty information in weapon system evaluations and risk assessments, and to prioritize future efforts. It also develops a strategy for improving the U.S. capability to assess injury risks.

Acceleration↗

PubMed1990

Injury impairment and disability scales to assess the permanent consequences of trauma.

Impairment and disability caused by injury are major public health costs in terms of monetary losses and personal suffering. Currently, there is no satisfactory method of measuring these losses. Impairment is the loss of function after injury healing. The level of impairment depends on the type and severity of injury in conjunction with medical-social factors. An Injury Impairment Scale (IIS) similar to the Abbreviated Injury Scale (AIS) is proposed, with severity codes of 0-6 like the AIS. The criteria of Mobility/Dexterity, Cognitive/Psychological, Cosmetic/Disfigurement, Sensory, Pain, and Sexual/Reproduction are used for coding impairment resulting from injury. Methods for determining whole body impairment (WBI) are discussed. Use of the highest impairment code on any criterion is suggested at this time to assign WBI. Disability depends on a patient's impairment and ability to accommodate the impairment. Factors such as education, past employment, family and community support, and personal and community resources play a role in the patient's ability to accommodate an impairment, fulfill the activities of daily living, socialize, and be productively employed. An Injury Disability Scale (IDS) and method of determining disability from impairment is proposed. Three patient case studies utilizing the proposed coding systems are presented. Validation of the injury impairment and disability scales will require in-depth evaluation by several institutes and medical facilities with large databases that include adequate follow-up examination information. This paper addresses the concepts for injury, impairment, and disability scaling and establishes a framework to undertake injury control research.

Disability Evaluation↗

PubMed1990

Involvement of older drivers in multivehicle side-impact crashes.

Side impacts were studied using three separate analyses. National Accident Sampling System (NASS) and National Crash Severity Study (NCSS) cases were reviewed on multivehicle crashes involving fatal chest and abdominal injury by interior contact. Twenty-five cases were analyzed and showed an unusually high involvement of older occupants. Analyses of the 1975-1986 FARS confirmed an overinvolvement. Sixty-four percent of near-side seated occupants were over 50 years old and 36% over 70 in fatal multivehicle side impacts. In contrast, 26% of victims in single-vehicle frontal crashes were over 50 and 8% over 70 years old. Analysis of the 1982-1986 NASS showed that single-vehicle side impacts are not an important injury risk for older drivers, except on icy or wet roads. In contrast, the risk of injury in multivehicle side impacts increases steadily with age and is a major problem for older drivers. The individual NASS and NCSS cases also showed that 88% of the multivehicle side crashes took place at an intersection and that the driver of the struck vehicle frequently caused the crash by driving error (48%) or traffic violation (16%). The majority of cases occurred in daylight hours, on dry roads, and without alcohol involvement. Changes in visual perception, judgment and attention of the older driver may be factors in their missing a traffic signal or turning in front of traffic under the right-of-way. In addition, a reduced tolerance to impact force probably contributes to the injury. Although an analysis of photographs of the side-impacted vehicle indicated that 44% had side-structure deformation that was similar to that produced in the National Highway Traffic Safety Administration (NHTSA) moving deformable barrier test, only 24%-32% of the cases actually addressed the proposed NHTSA dynamic side-impact test. The results of this analysis bear on the agency's preliminary regulatory impact analysis.

Abdominal Injuries↗

PubMed1990

Anthropometry of seated women during pregnancy: defining a fetal region for crash protection research.

An anthropometric description was developed for the fetal region of women at three, six, and nine months of pregnancy. This involved superimposing a fetal ellipse on abdominal and pelvic ellipses of seated women from a previous study. The data were developed for women of 5th, 50th, and 95th percentile size. The ellipses identify body contact zones on the side and front which would interact with the fetal region in a crash. The new information provides spatial characteristics of pregnant women for the development of test dummies, accommodating restraints, and friendly interiors and for enhancing crash protection. This research addresses the 342 deaths of pregnant women estimated to occur annually in motor vehicle crashes.

Accidents, Traffic↗

PubMed1989

Biomechanics of injury in lateral impacts.

Fourteen anesthetized swine were subjected to blunt lateral impact at velocities of 4.3, 6.7, or 8.2 m/s with a 15 cm flat pendulum weighing 23.4 kg accelerated to impact speed by a power-assisted pneumatic impactor. Injuries consisted of laceration of the liver and spleen resulting in severe hemoperitoneum and death by ventricular fibrillation and respiratory arrest in the highest severity impacts. Logist analysis of the biomechanical responses and serious or fatal injury indicated that the maximum Viscous response (VC) had the best correlation with injury risk. A tolerance level of VC = 0.89 m/s was determined for a 25% probability of serious injury. In contrast, maximum chest compression did not correlate with injury. The experiments indicate that internal organ and soft tissue injury may occur by a Viscous mechanism during the rapid phase of compression of the body. The Viscous response is an effective measure of injury risk in side impacts.

Accidents, Traffic↗

PubMed1989

Biomechanics of the human chest, abdomen, and pelvis in lateral impact.

Fourteen unembalmed cadavers were subjected to 44 blunt lateral impacts at velocities of approximately 4.5, 6.7, or 9.4 m/s with a 15 cm flat circular interface on a 23.4 kg pendulum accelerated to impact speed by a pneumatic impactor. Chest and abdominal injuries consisted primarily of rib fractures, with a few cases of lung or liver laceration in the highest severity impacts. There were two cases of pubic ramus fracture in the pelvic impacts. Logist analysis of the biomechanical responses and injury indicated that the maximum Viscous response had a slightly better correlation with injury than maximum compression for chest and abdominal impacts. A tolerance level of VC = 1.47 m/s for the chest and VC = 1.98 m/s for the abdomen were determined for a 25% probability of critical injury. Maximum compression was similarly set at C = 38% for the chest and at C = 44% for the abdomen. The experiments indicate that chest and abdominal injury may occur by a viscous mechanism during the rapid phase of body compression, and that the Viscous and compression responses are effective, complementary measures of injury risk in side impact. Although serious pelvic injury was infrequent, lateral public ramus fracture correlated with compression of the pelvis, not impact force or pelvic acceleration. Pelvic tolerance was set at 27% compression.

Abdominal Injuries↗

PubMed1989

Invalidity of speculated injury mechanism in autopsy reports.

Postmortem and crash investigation reports were examined for 35 cases of belted automotive crash fatalities. This paper highlights those cases with speculation of the injury mechanism in the post mortem report. In two cases, the medical examiner made specific reference to a 'whiplash' mechanism of brain injury, which refers to an inertial loading of the neck without head contact. Examination of the car interior in one case indicated evidence of head contact with transfer of hair, and the other facial contact with transfer of teeth. Death was more likely due to direct head impact. In another case, the vehicle was struck laterally by another car on the far side of the driver. The medical examiner stated that the driver incurred typical 'steering wheel type' injury, while examination of the car interior indicated no consequential contact between the driver and the steering wheel. Instead, the intruding passenger door probably impacted the driver at a velocity high enough to induce fatal chest injuries. These cases demonstrate the necessity of a thorough examination of contact points in the crashed car to discern the mechanism of injury and to reconstruct the kinematics of injured occupants in a crash. They also demonstrate how 'popular' misunderstanding of mechanisms of fatal injury may be introduced and perpetuated.

Accidents, Traffic↗

PubMed1989

Injury biomechanics research: an essential element in the prevention of trauma.

The central aspects of injury biomechanics research are defined and research approaches described. These aspects include the identification and definition of impact injury mechanisms, the quantification of biomechanical response to impact, the determination of impact tolerance levels, and the development and use of injury assessment devices and techniques for evaluating injury prevention systems. The current status of knowledge and technology is then reviewed for the head, cervical spine, thorax, abdomen, and lower extremity. Important gaps are identified, and research priorities emphasizing functional impairment are proposed.

Abdominal Injuries↗

PubMed1988

Limits and challenges of crash protection.

The objective of this paper is to present information on fatal motor vehicle crashes, the effectiveness of lap-shoulder belts in preventing these deaths, and the limitations on their lifesaving capabilities. With this perspective, an evaluation is made of the potential for further reductions in crash fatalities if advanced safety systems are included in the standard occupant protection package. These systems might include additional lap-shoulder belt technologies, such as pretensioners, webbing locks or grabbers, load limiters, and adjustable anchors, as well as belt supplements, such as air bags and energy-absorbing interiors. Difficulties encountered in evaluating the effectiveness of these systems in the laboratory are then described. Finally, the potential for precrash and postcrash safety technologies in combination with crash-phase technology is discussed as an effective use of resources to improve occupant protection.

Accidents, Traffic↗

PubMed1988

A viscous tolerance criterion for soft tissue injury assessment.

Experiments in our laboratory have documented that high-speed impact can cause severe injury to internal organs before either of the currently accepted chest injury criteria, which are based on spinal acceleration or chest compression, approach their tolerance limit. Those studies demonstrate an interdependence between the velocity of deformation and compression of the body on injury risk. A tolerable level of chest compression at a low velocity can prove to be fatal at higher velocities of deformation. The observation of a rate-sensitive tolerable compression led to the introduction of the Viscous criterion, VCmax, which accounts for the importance of both parameters. VCmax is the maximum of the product of velocity of deformation (V) and compression (C), and is derivable from the chest deflection response. This paper presents the empirical evidence and theoretical basis supporting the Viscous criterion, and shows it to be an indicator of the energy dissipated by soft tissue deformation. The Viscous criterion accurately predicts the risk of vital organ and soft tissue injury when other criteria fail.

Acceleration↗