Lap-shoulder Belt Research Articles

Mortality reduction with air bag and seat belt use in head-on passenger car collisions.

To assess the efficacy of occupant protection systems, the authors measured the mortality reduction associated with air bag deployment and seat belt use for drivers involved in head-on passenger car collisions in the United States. They used a matched case-control design of all head-on collisions involving two passenger cars reported to the Fatality Analysis Reporting System in 1992-1997, and driver mortality differences between the paired crash vehicles for air bag deployment and seat belt use were measured with matched-pair odds ratios. Conditional logistic regression was used to adjust for multiple effects. There were 9,859 head-on collisions involving 19,718 passenger cars and drivers. Air bag deployment reduced mortality 63% (crude odds ratio (OR) = 0.37, 95% confidence interval (CI): 0.32, 0.42), while lap-shoulder belt use reduced mortality 72% (OR = 0.28, 95% CI: 0.25, 0.31). In a conditional logistic model that adjusted for vehicle (rollover, weight, age) and driver (age, sex) factors, air bags (OR = 0.71, 95% CI: 0.58, 0.87) and any combination of seat belts (OR = 0.25, 95% CI: 0.22, 0.29) were both associated with reduced mortality. Combined air bag and seat belt use reduced mortality by more than 80% (OR = 0.18, 95% CI: 0.13, 0.25). Thus, this study confirms the independent effect of air bags and seat belts in reducing mortality.

Booster seat use and reasons for nonuse.

Many children 4 to 9 years old are inappropriately restrained in vehicles and are at risk for injury in crashes. This study was undertaken to determine the rate of booster seat use and the reasons for nonuse. Observations were conducted at a random sample of day care centers, and drivers of unrestrained children 4 to 8 years old were interviewed to determine the reasons for lack of booster seat use. Observations were conducted on 149 children. Shoulder belt use significantly increased with the age of the child; 28.3% of 4-year-olds and 70.0% of 6- to 8-year-olds used lap-shoulder belts. Overall, 27.7% of children in the target age group used booster seats; only 10% of children 6 to 8 years old were restrained with booster seats. Booster seat use decreased when there were 3 or more passengers in the vehicle. The most common reason for lack of booster seat use was that parents thought the child was large enough to use the regular lap-shoulder belt system, or problems with attempting to use the seat in the vehicle. More than one half of parents who were not using booster seats at the time of the survey reported owning seats. This study indicates that parental misconceptions about size and safety of regular restraint equipment are the most common reason that children are not appropriately restrained in vehicles. This information can be used to guide community intervention programs.

Strengthening Motor Vehicle Occupant Protection Laws: American College of Preventive Medicine Public Policy Statement

Burden of Suffering Motor vehicle injuries are the seventh leading cause of death in the United States, killing 40,000 Americans and disabling 1,800,000 each year. (1) Motor vehicle crashes are responsible for more traumatic brain and spinal cord injuries and more potential years of life lost in the United States than any other cause and are the leading cause of death among Americans 5-32 years of age. (1) The death rate from motor vehicle collisions, 1.8/100 million vehicle miles/year, has been gradually declining, a multifactorial trend thought to be associated with improved automobile design and safety features (such as seat belts, collapsible steering columns, improved auto body design) lowered speed limits, improvements in road design, and stringent enforcement of traffic safety laws. (2) Legislation mandates that U.S. automobiles manufactured after September 1, 1989, have automated protection (either air bags, motorized shoulder belt, or automatic lap-shoulder belts anchored to the door) as well as lap-shoulder belts in the rear seats. The air bag is a supplemental restraint system, designed to be used together with lap-shoulder seat belt restraints. Unlike other improvements, seat-belt effectiveness depends directly on their correct use; in most states, despite legislation, only about two thirds of the population use seat belts. (3) Groups with lower use of seat belts are often young drivers, drinking drivers, and those who disobey other traffic laws. (4)

Pediatric cervical spine injury: a three-year experience.

Traumatic injuries of the cervical spine are uncommon in pediatrics. Children less than 8 years of age are reported to have "exclusively" upper cervical injuries. Recent experience at The Children's Hospital of Alabama (TCHA) challenged both of these notions. A concurrent retrospective chart review of all cervical spine injuries treated at TCHA between January 1, 1992 and December 31, 1994 was performed. Data collected included patient demographics, date and time of injury, mechanism and site of injury, presence of associated injuries, clinical management, and outcome. Thirty-four patients with cervical spine injuries were seen at TCHA in the 36-month study period. The leading mechanism of injury was motor vehicle crashes (23/34 or 68%). Head injuries were associated with cervical spine injury in 53% of patients. Of the 20 patients aged 8 years or less, 10 (50%) had "low" cervical spine injuries (below C4). Overall mortality was 41% (14/34). Of the 15 vehicle occupants, 12 were unrestrained or inappropriately restrained. Two of those appropriately restrained were young school-aged children in lap-shoulder belts who sustained isolated cervical spine injuries. 1. The number of pediatric cervical spine injuries in our institution appears to be increasing. 2. Cervical spine injury in children less than 8 years of age are not exclusively confined to the region above C4. 3. Occurrence of cervical spine injuries despite lap-shoulder belt use suggests that efforts should be focused on refinement of motor vehicle restraint devices in young school-aged children.

The effects of seat belts on injury severity of front and rear seat occupants in the same frontal crash

Data on passenger cars in frontal crashes were reviewed using NASS 1980–1991. Only crashes with one or more rear seat passengers were included. Combinations (pairs) were made based on restraint use: lap-shoulder belts in the front seat (or no belts worn) and lap belts, (or belts worn) in the rear seat. Passive belts or child restrained occupants were not included. The AIS was used for injury severity. The data indicate the rear seat to be a safer environment. Lap belted rear seat occupants always fared better than their front seat counterparts.

A Fatality Associated with the Deployment of an Automobile Airbag

Airbags have become an increasingly accepted automobile safety feature that can reduce the morbidity and mortality associated with motor vehicle collisions. We present the following case report of an unusual fatality with multiple internal injuries from a minor mechanism motor vehicle collision. The cause of injuries was determined to be secondary to the deployment of a driver's side airbag without the concomitant use of a lap-shoulder belt.

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.

Vertebral Column Injuries and Lap-Shoulder Belts

To present cases of vertebral column fractures or fracture dislocations that occur to restrained front seat occupants where there is no evidence of body contact with interior car components based on both medical records and car inspection. Reviewed were car crash injury cases investigated at the University of Michigan Transportation Research Institute and at the University of Birmingham (England) as well as the National Accident Severity Study files of the National Highway Traffic Safety Administration. Medical records and car inspections in the cases presented did not indicate any evidence of body contact with interior car structures. Vertebral fractures or fracture dislocations sustained by front seat occupants who were wearing lap-shoulder belts are rare, as evidenced by the relatively few cases identified in the literature and in the crash injury files reviewed. Infrequently, in frontal crashes, vertebral fractures or fracture dislocations can occur to lap-shoulder belted front seat car occupants without head or torso impacts with interior car structures. Cervical spine injuries are due to neck flexion over the shoulder portion of the restraint. Thoracolumbar fractures can occur in the frontal crash even at low crash velocity.

Thoracic and lumbar spine injuries and the lap-shoulder belt : D. F. Huelke and M. Ostrom. SAE Technical Paper Series, #930640

Thoracic and lumbar spine injuries and the lap-shoulder belt : D. F. Huelke and M. Ostrom. SAE Technical Paper Series, #930640

Intraabdominal injuries associated with lap-shoulder belt usage : D.F. Huelke, G.M. Mackay, and A. Morris. SAE Technical Paper Series, #930639.

Intraabdominal injuries associated with lap-shoulder belt usage : D.F. Huelke, G.M. Mackay, and A. Morris. SAE Technical Paper Series, #930639.

Comparison of motor vehicle occupant injuries in restrained and unrestrained 4-to 14-year-olds

This study compares injuries of restrained and unrestrained 4- to 14-year-olds in nine emergency rooms and the Coroner's office in Orange County, California from 1983 to 1989. Analyses were performed separately for 4- to 9- and 10- to 14-year-olds because of differences related to the fit of the seat belt. Significantly fewer intracranial injuries and a significantly lower mean Injury Severity Score (ISS) were seen between the restrained and unrestrained for 10- to 14-year-olds in the front passenger and back seats; but for 4- to 9-year-olds in the back seat only. These same differences were noted between restrained 4- to 9-year-olds in the back compared with those in the front passenger seat. Except for 4- to 9-year-olds in the front passenger seat, our findings are consistent with similar studies of occupants of all ages. Our results suggest that lap-shoulder belts (primary restraint in front seat) may provide less protection for 4- to 9-year-olds than for 10- to 14-year-olds and adults.

A review of cervical fractures and fracture-dislocations without head impacts sustained by restrained occupants

Crash injury reduction via lap-shoulder belt use has been well documented. Like any other interior car component, lap-shoulder belts may be related to injury in certain crashes. Relatively unknown is the fact that cervical fractures or fracture-dislocations to restrained front seat occupants occur where no head contact was evidenced by both medical records and car inspection. A review of the available literature on car crash injuries revealed more than 100 such cases. A review of the National Accident Severity Study (NASS) 80–88 file was also conducted, revealing more examples. Case capsule descriptions from the authors' files are also detailed along with examples of such injuries in infants and children in child restraints. However, cervical fractures or fracture dislocations are rare, as evidenced by the relatively few cases identified in the literature, in the author's files, and by an analysis of NASS 80–90 data that revealed a cervical spine injury frequency of only .4% at the AIS-3 level (Hueike, Morris, and Mackay 1992).

PATTERNS OF FRACTURE AFTER AIR BAG DEPLOYMENT

The airbag restraint system has been described as a means of reducing fatalities in frontal crashes. This conclusion is based on crash investigations and statistical extrapolation, but few data exist to document specific fracture patterns and injuries after airbag deployment. Seven cases of driver's side airbag deployment after motor vehicle crashes were studied for extent of injury. Unrestrained (non-seatbelted) drivers demonstrated flexion injuries of the cervical and thoracic spine and direct impaction fractures of the face and sternum. One restrained (lap-shoulder belt) driver demonstrated an extension injury of the upper cervical spine. What may emerge from further study is a decrease in fatalities, but also a pattern of fractures specific to airbag use.

Field investigations of the performance of air bag deployments in frontal collisions

This paper documents field investigations of “air bag” crashes selected from a large group of air bag crashes in file at the University of Michigan Transportation Research Institute (UMTRI). A full range of crashes are presented with injury levels of AIS 1–2 to AIS 5–6. Most occupants sustained minor injuries. Those not wearing the lap-shoulder belt (3-point belt) had more minor injuries than the restrained. The occurrence of higher level injuries (AIS ⩾2) was found more often in the nonbelted.

Retinal Detachment Caused by Air Bag Injury

A 40-year-old man drove his automobile into a road-side ditch to avoid an oncoming car. He struck a tree stump at a speed of 10 to 15 miles per hour, causing inflation of the driver's-side air bag, which struck his face and upper body. He did not strike any other components of the car's interior. He was wearing a three-point lap-shoulder belt and was not wearing glasses. Immediately after the accident, the patient noted visual loss in the right eye. A vitreous hemorrhage was noted by his ophthalmologist. One month later he was noted to have developed a retinal detachment in the right eye. His visual acuity was hand motions in the right eye and 20/15 OS. Examination results of the left eye were normal. In the right eye, intraocular pressure was 41 mm Hg and inferior angle recession was present. There were 2+ cells and 3+ flare in the

Comparison of motor vehicle occupant injuries in restrained and unrestrained 4- to 14-year-olds

This study compares injuries of restrained and unrestrained 4- to 14-year-olds in nine emergency rooms and the Coroner's office in Orange County, California from 1983 to 1989. Analyses were performed separately for 4- to 9- and 10- to 14-year-olds because of differences related to the fit of the seat belt. Significantly fewer intracranial injuries and a significantly lower mean Injury Severity Score (ISS) were seen between the restrained and unrestrained for 10- to 14-year-olds in the front passenger and back seats; but for 4- to 9-year-olds in the back seat only. These same differences were noted between restrained 4- to 9-year-olds in the back compared with those in the front passenger seat. Except for 4- to 9-year-olds in the front passenger seat, our findings are consistent with similar studies of occupants of all ages. Our results suggest that lap-shoulder belts (primary restraint in front seat) may provide less protection for 4- to 9-year-olds than for 10- to 14-year-olds and adults.

Severe Ocular Trauma From a Driver's-Side Air Bag

Motor vehicle accidents are a common cause of ocular trauma in the United States. Most ocular injuries occur in patients not wearing a lap-shoulder seat belt. 1,2 The air bag was recently introduced as a method to reduce the consequences of frontal and front angle collisions, which account for more than 50% of motor vehicle accidents involving serious injuries and fatalities. 3 Air bags have been estimated to reduce the incidence of brain injury in motor vehicle accidents by as much as 25%. 3 Inflation of an air bag may also reduce the frequency and severity of ocular trauma. We describe herein a patient who sustained significant ocular trauma from an inflated air bag during a motor vehicle accident. Report of a Case. —A 26-year-old man driving 35 miles per hour and restrained by a three-point lap-shoulder belt crashed head-on into a tree. The driver's-side air bag inflated during the

Lesion of the Internal Carotid Artery Caused by a Car Safety Belt

A description is given of a case of complete obstruction of the internal carotid in a patient wearing a lap-shoulder belt. This was presumed due to direct contusion of the vessel at the C2 level.

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.

Nonpenetrating subclavian artery trauma.

Nonpenetrating injury to the subclavian vessels is uncommon. During a 6-year period we have treated 167 patients with injuries to the subclavian and superior mediastinal arteries. Fifteen of these injuries (9%) occurred after blunt trauma. In 10 patients the proximal segment (first and second parts) of the artery was involved. No patient had an isolated injury; the most frequent associated injuries were rib fractures (n = 11), with the first rib being involved in four of these. Total brachial plexus disruption was found in nine patients. All patients with distal artery involvement had a clavicular fracture. All had an absent radial pulse and eight had critical ischemia of the hand. Four patients were treated nonoperatively and the remainder were treated along standard lines. Brachial plexus reconstruction was not feasible in any patient. Within 2 weeks of operation, one patient died as a result of head injuries and one required amputation because of sepsis. During a 12-month period, five regained full function, one additional patient requested above-elbow amputation after 6 months, and seven had a flail anesthetic limb. Twelve of these patients were involved in automobile accidents, eight of whom were wearing lap-shoulder harness seat belts with a loose-fitting shoulder strap component that created a characteristic abrasion pattern on the torso and chest. We conclude that the torsionshearing motion allowed by this situation contributed significantly to the pattern of injury and a plea is made for correctly fitted restraining devices.