Thoracolumbar junction injuries after rollover crashes: difference between belted and unbelted front seat occupants

Age-based variability in the association between restraint use and injury type and severity in multi-occupant crashes

PURPOSE

Previous studies have shown older adults receive relatively less protection from seat belts against fatal injuries, however it is unknown how seat belt protection against severe and torso injury changes with age. We estimated age-based variability in seat belt protection against fatal injuries, injuries with maximum abbreviated injury scale greater than two (MAIS 3+), and torso injuries.

METHODS

We leveraged the Crash Outcome Data Evaluation System to analyze binary indicators of fatal, MAIS 3+, and torso injuries. Using a matched cohort design and conditional Poisson regression, we estimated age-based relative risks (RR) of the outcomes associated with seat belt use.

RESULTS

Our results suggested that seat belts were highly protective against fatal injuries for all ages. For ages 16-30, seat belt use was associated with 66% lower risk of MAIS3+ injury (RR 0.34, 95% CI 0.30, 0.38) for occupants of the same vehicle, whereas for ages 75 and older, seat belt use was associated with 38% lower risk of MAIS3+ injury (RR 0.62; 95% CI 0.45, 0.86) for occupants in the same vehicle. The association between restraint use and torso injury also attenuated with age.

CONCLUSIONS

In multi-occupant crashes, seat belts were highly protective against fatal and MAIS3+ injury, however seat belt protection against MAIS3+ and torso injury attenuated with age.

Difference in severity and distribution of bodily injuries following collision between drivers of K-cars and standard vehicles

BACKGROUND

Although K-cars, small four-wheeled vehicles with an engine capacity of <660 cc, have been used almost exclusively in Japan, they have recently become increasingly popular in other countries. Therefore, reporting the characteristics of bodily injuries sustained by K-car drivers after road traffic accidents (RTAs) may be important not only for health professionals but also for car manufacturers.

METHODS

A single-center, retrospective observational study was conducted using prospectively acquired data. Between January 2010 and December 2017, 494 restrained drivers (331 men/163 women with a mean age of 45.1 years) whose vehicles had been severely damaged in RTAs underwent whole-body computed tomography prospectively. They were subsequently dichotomized into 221 K-car drivers and 273 standard vehicle drivers and compared for severity and distribution of bodily injuries.

RESULTS

K-car drivers tended to be older and were significantly more likely to be female than standard vehicle drivers. The frequency of subjects with severe bodily injuries significantly higher among K-car drivers than among standard vehicle drivers (21.7% vs. 14.3%; p = 0.04), and the frequency of bowel/mesentery injuries tended to be higher in the former (9.0% vs. 4.4%; p = 0.06). However, the frequency of abdominal solid viscus injuries did not differ significantly between the two groups. Multivariable regression analysis showed that age [odds ratio (OR): 1.022; 95% confidence interval (CI): 0.998-1.047; p = 0.07] and K-cars (OR: 3.708; 95% CI: 0.984-6.236; p =  0.05) tended to be associated with bowel/mesentery injuries in restrained drivers. The frequency of pelvic/hip fractures also tended to be higher in K-car drivers than in standard vehicle drivers (5.9% vs. 2.6%; p =  0.10). By contrast, the severity and frequency of the upper torso injuries were similar between the two groups.

CONCLUSIONS

Compared to standard vehicle drivers, K-car drivers seem to experience more severe bodily injuries after severe RTAs. Despite there being no answer for the increased frequency of only hollow viscus injuries but not solid viscus injuries among restrained K-car drivers, advanced age may, at least in part, be responsible. Given the limitations inherent to this study's single-center, retrospective design, multi-center prospective studies are warranted to verify our findings.

Seatbelt use and risk of major injuries sustained by vehicle occupants during motor-vehicle crashes: a systematic review and meta-analysis of cohort studies

Background

In 2004, a World Health Report on road safety called for enforcement of measures such as seatbelt use, effective at minimizing morbidity and mortality caused by road traffic accidents. However, injuries caused by seatbelt use have also been described. Over a decade after publication of the World Health Report on road safety, this study sought to investigate the relationship between seatbelt use and major injuries in belted compared to unbelted passengers.

Methods

Cohort studies published in English language from 2005 to 2018 were retrieved from seven databases. Critical appraisal of studies was carried out using the Scottish Intercollegiate Guidelines Network (SIGN) checklist. Pooled risk of major injuries was assessed using the random effects meta-analytic model. Heterogeneity was quantified using I-squared and Tau-squared statistics. Funnel plots and Egger’s test were used to investigate publication bias. This review is registered in PROSPERO (CRD42015020309).

Results

Eleven studies, all carried out in developed countries were included. Overall, the risk of any major injury was significantly lower in belted passengers compared to unbelted passengers (RR 0.47; 95%CI, 0.29 to 0.80; I² = 99.7; P = 0.000). When analysed by crash types, belt use significantly reduced the risk of any injury (RR 0.35; 95%CI, 0.24 to 0.52). Seatbelt use reduces the risk of facial injuries (RR = 0.56, 95% CI = 0.37 to 0.84), abdominal injuries (RR = 0.87; 95% CI = 0.78 to 0.98) and, spinal injuries (RR = 0.56, 95% CI = 0.37 to 0.84). However, we found no statistically significant difference in risk of head injuries (RR = 0.49; 95% CI = 0.22 to 1.08), neck injuries (RR = 0.69: 95%CI 0.07 to 6.44), thoracic injuries (RR 0.96, 95%CI, 0.74 to 1.24), upper limb injuries (RR = 1.05, 95%CI 0.83 to 1.34) and lower limb injuries (RR = 0.77, 95%CI 0.58 to 1.04) between belted and non-belted passengers.

Conclusion

In sum, the risk of most major road traffic injuries is lower in seatbelt users. Findings were inconclusive regarding seatbelt use and susceptibility to thoracic, head and neck injuries during road traffic accidents. Awareness should be raised about the dangers of inadequate seatbelt use. Future research should aim to assess the effects of seatbelt use on major injuries by crash type.

Electronic supplementary material

The online version of this article (10.1186/s12889-018-6280-1) contains supplementary material, which is available to authorized users.

Airbag deployment and cervical spine injury in restrained drivers following motor vehicle collisions

PURPOSE

Seatbelts and airbags are the most important devices protecting drivers from cervical spine injury (CSI) following motor vehicle collisions (MVCs). However, there have been few reports on the radiographic characteristics of CSI sustained by restrained, airbag-deployed drivers.

METHODS

A single-center, retrospective observational study was conducted using prospectively acquired data. Between January 2011 and December 2017, 564 restrained drivers, whose vehicle had been severely damaged in MVCs, underwent whole-body computed tomography for evaluation of bodily injuries. The drivers were dichotomized into airbag (+) group (n = 218) and airbag (-) group (n = 139), after excluding 207 drivers in whom airbag deployment status was unknown.

RESULTS

Eight and nine drivers sustained CSIs in the airbag (+) and airbag (-) group, respectively. The frequency of CSI did not differ significantly between the two groups (3.7% vs. 6.5%, p = 0.31). All eight CSIs in the airbag (+) group were classified as hyperextension injuries, and four of them sustained concomitant spinal cord injuries caused by dislocation. Within the airbag (+) group, the drivers with CSIs were significantly older than those without CSIs (65.2 ± 18.5 vs. 44.8 ± 18.7 years, p = 0.002).

CONCLUSION

Although it is without doubt that the combination of seatbelt and airbag reduces the frequency and severity of CSIs following MVCs, the CSIs sustained in restrained, airbag (+) drivers may not always be mild, and elderly drivers may be at an elevated risk of CSI. In addition, the possibility of a causal role of airbags in CSI requires consideration in this population.

Heterogeneous impacts of gender-interpreted contributing factors on driver injury severities in single-vehicle rollover crashes

In this study, a mixed logit model is developed to identify the heterogeneous impacts of gender-interpreted contributing factors on driver injury severities in single-vehicle rollover crashes. The random parameter of the variables in the mixed logit model, the heterogeneous mean, is elaborated by driver gender-based linear regression models. The model is estimated using crash data in New Mexico from 2010 to 2012. The percentage changes of factors' predicted probabilities are calculated in order to better understand the model specifications. Female drivers are found more likely to experience severe or fatal injuries in rollover crashes than male drivers. However, the probability of male drivers being severely injured is higher than female drivers when the road surface is unpaved. Two other factors with fixed parameters are also found to significantly increase driver injury severities, including Wet and Alcohol Influenced. This study provides a better understanding of contributing factors influencing driver injury severities in rollover crashes as well as their heterogeneous impacts in terms of driver gender. Those results are also helpful to develop appropriate countermeasures and policies to reduce driver injury severities in single-vehicle rollover crashes.

Epidemiology, causes and prevention of car rollover crashes with ejection

Rollover crashes (ROCs) are responsible for almost a third of all highway vehicle occupant fatalities. Although ROCs are common and serious mechanism of injury, ROCs are under-reported. To analyze the causes, mechanism, impact and prevention of ROCs, we reviewed the literature between 1984 and 2013. By utilizing the search engines PubMed, MEDLINE and EMBASE by using key words “ROCs” “Ejection” and “vehicle” the initial search yielded 241 abstracts, of which 58 articles were relevant. Most of the articles were either retrospective or experimental studies funded by automobile companies. All vehicles are susceptible to rollovers to certain extents. Despite continuing innovation in vehicles’ safety, human factor is pivotal in prevention of ROCs. Distracted driving, speeding and drinking escalate the chances of rollover crashes. Wearing a seatbelt greatly improves the chances of surviving a ROC.

Posterior tension band wiring and instrumentation for thoracolumbar flexion-distraction injuries

PURPOSE

To evaluate treatment outcome of tension band wiring followed by posterior spinal fusion and instrumentation for thoracolumbar flexiondistraction injury (FDI).

METHODS

36 men and 12 women aged 21 to 56 (mean, 36) years underwent tension band wiring followed by posterior spinal fusion and instrumentation using pedicular screws for FDI of the thoracolumbar spine. The injured vertebral levels were T11 (n=2), T12 (n=12), T11-T12 (n=1), T12-L1 (n=1), L1 (n=28), and L2 (n=4). Anterior vertebral body height and kyphosis were measured before and after surgery. Neurologic status was assessed using the American Spinal Injury Association (ASIA) scale. The Oswestry Disability Index questionnaire and visual analogue scale for pain were also used.

RESULTS

The mean follow-up was 38 (range, 26-72) months. At final follow-up, the mean visual analogue scale for pain was 1.7, and the median Oswestry Disability Index was 4% (range, 0-32%). The mean anterior vertebral body height improved from 20.5 to 38.8 mm (p<0.001). The mean kyphosis improved from 20.4º to 1.5º (p<0.001). Four patients had persistent neurologic deficit: ASIA scale C (n=2) and D (n=2); their ASIA scales improved by one grade. All patients returned to their original work at 6 months. There were no intra-operative complications or implant failures.

CONCLUSION

Posterior tension band wiring followed by posterior spinal fusion and instrumentation for thoracolumbar FDIs achieved good outcome.

Location of sternal fractures as a possible marker for associated injuries

Introduction. Sternal fractures often occur together with serious and life-threatening additional injuries. This retrospective study was designed to assess concomitant injuries and develop a correlation between fracture location and the severity of injury. Methods. All patients (n = 58) diagnosed with a fracture of the sternum by means of a CT scan were analysed with respect to accident circumstances, fracture morphology and topography, associated injuries, and outcome. Results. Isolated sternal fractures occurred in 9%. In all other admissions, concomitant injuries were diagnosed: mainly rip fractures (64%), injury to the head (48%), the thoracic spine (38%), lumbar spine (27%), and cervical spine (22%). Predominant fracture location was the manubrium sterni. In these locations, the observed mean ISS was the highest. They were strongly associated with thoracic spine and other chest injuries. Furthermore, the incidence of head injuries was significantly higher. ICU admission was significantly higher in patients with manubrium sterni fractures. Conclusion. Sternal fractures are frequently associated with other injuries. It appears that the fracture location can provide important information regarding concomitant injuries. In particular, in fractures of manubrium sterni, the need for further detailed clinical and radiologic workup is necessary to detect the frequently associated injuries and reduce the increased mortality.

Hybrid cadaveric/surrogate model of thoracolumbar spine injury due to simulated fall from height

A fall from high height can cause thoracolumbar spine fracture with retropulsion of endplate fragments into the canal leading to neurological deficit. Our objectives were to develop a hybrid cadaveric/surrogate model for producing thoracolumbar spine injury during simulated fall from height, evaluate the feasibility and performance of the model, and compare injuries with those observed clinically. Our model consisted of a 3-vertebra human lumbar specimen (L3-L4-L5) stabilized with muscle force replication and mounted within an impact dummy. The model was subjected to a fall from height of 2.2 m with impact velocity of 6.6 m/s. Kinetic and kinematic time-history responses were determined using spinal and pelvis load cell data and analyses of high-speed video. Injuries to the L4 vertebra were evaluated by fluoroscopy, radiography, and detailed anatomical dissection. Peak compression forces during the fall from height occurred at 7 ms and reached 44.7 kN at the ground, 9.1 kN at the pelvis, and 4.5 kN at the spine. Pelvis acceleration peaks reached 209.9 g at 8 ms for vertical and 62.8 g at 12 ms for rearward. Tensile load peaks were then observed (spine: 657.0 N at 47 ms; pelvis: 569.4 N at 61 ms). T1/pelvis peak flexion of 68.3° occurred at 38 ms as the upper torso translated forward while the pelvis translated rearward. Complete axial burst fracture of the L4 vertebra was observed including endplate comminution, retropulsion of bony fragments into the canal, loss of vertebral body height, and increased interpedicular distance due to fractures anterior to the pedicles and a vertical split fracture of the left lamina. Our dynamic injury model closely replicated the biomechanics of real-life fall from height and produced realistic, clinically relevant burst fracture of the lumbar spine. Our model may be used for further study of thoracolumbar spine injury mechanisms and injury prevention strategies.

Preventing motor vehicle crashes related spine injuries in children

BACKGROUND

Spinal cord injury (SCI) is a devastating event that results in permanent disability for injured children. Among all etiologies of SCI, motor vehicle crashes (MVCs) are the leading cause and account for 29% of all traumatic SCIs in children. We tried to evaluate types and mechanisms of MVC-related spinal column and spinal cord injuries, risk factors, safety issues and legislation.

DATA SOURCES

A literature review was performed using PubMed from 1966 to 12th April 2010 with the following key words: children OR pediatric, spine, injury OR trauma, restraint, seat belt, motor vehicle, road OR traffic, collision OR crash, safety. Cross referencing of discovered articles was also performed.

RESULTS

Risk factors for MVC-related SCI include single vehicle crashes, vehicle rollover, and ejection of the passenger from the vehicle. Any anatomic region of the spinal cord may be injured as a result of MVC and may vary according to the type of accident and restraint system usage. Increasing use of three-point seat belts, which are more protective than isolated lap seat belts, has decreased the incidence of MVC-related SCI. There is evidence that airbag use without seatbelt use is associated with an increased risk of cervical spine fractures with or without SCI. Vehicle designers need to give more attention to the prevention of vehicle rollover and to improve occupant protection when rollover occurs.

CONCLUSIONS

MVC is a common cause of SCI in children; therefore, paying attention to risk factors and modes of prevention is important. As MVC-related SCI can lead to permanent disability, prevention and education play an important role in decreasing childrens' morbidity and mortality. Making behavior, roads and vehicles safer can significantly reduce MVC-related SCI in children.