Serious-to-fatal injury to second-row occupants in rear impacts using 1994-2020 field data

OBJECTIVE

Serious-to-fatal injury was analyzed for second-row children aged 0-14 years and adults aged 15 and older in rear impacts by body region, restraint use, and injury mechanism using field data collected by NHTSA.

METHOD

1994-2015 NASS-CDS and 2017-2020 CISS data were used to investigate the rate for Maximum Abbreviated Injury Scale (MAIS) 3 + F injury in rear crashes involving 1994+ model year vehicles. All second-row occupants were included, irrespective of restraint use and ejection status. The data were analyzed by group: children (0-14 years old) and adults (15+ years old). All available electronic files for seriously injured second-row occupants in the rear impacts were reviewed for mechanism of injury.

RESULTS

The rate of serious injury (MAIS 3 + F) for second-row occupants was 0.93% ± 0.36% in rear crashes; it was 0.76% ± 0.39% for children and 1.22% ± 0.40% for adults. There were 2.8 AIS 3+ injuries per seriously to fatally injured occupant on average. Most serious injuries occurred to the head in children and to the head and chest in adults. Restraint use was only 31.3% for all seriously injured second-row occupants in the rear impacts. It was 45.1% for children and 17.8% for adults. The overall rate of serious injury in rear impacts was 10.0 times higher when unrestrained than restrained overall; it was 5.6 times higher for children and 20.2 times higher in adults. The case review indicated that many young children were improperly restrained or placed in the incorrect child seat. More than 17% of second-row adults were ejected; all were unrestrained. The primary mechanism for child injury was related to intrusion (86.0%). About 14% was not related to intrusion; 12.3% involved the front seat rotating rearward into the child. The primary mechanisms for adult injury differed from those for children; 68.0% was related to intrusion, 21.6% was not related to intrusion, and 10.4% involved ground impact with ejection. Of the non-intrusion-related cases, 19.1% involved acceleration forces injuring the adult and 2.5% involved the front seat rotating rearward.

CONCLUSIONS

The primary mechanism for serious injury to second-row occupants in rear crashes was intrusion either by direct force, compression into front components, or acceleration into forward components. The front seat moving rearward was an infrequent cause for injury.

Preventive Effectiveness of Thoracic Side Airbags in Side-Impact Crashes Based on Korea In-Depth Accident Study (KIDAS) Database

Studies on the effectiveness of thoracic side airbags (tSABs) in preventing thoracic injuries is limited and conflicting. This retrospective observational study aims to evaluate the effectiveness of tSABs in side-impact crashes based on data for motor vehicle occupants (MVOs) who visited an emergency department in Korea. The data were obtained from the Korean In-Depth Accident Study (KIDAS) database for patients treated at Wonju Severance Christian Hospital between January 2011 and April 2020. Of the 3899 patients with road traffic injuries, data for 490 patients were used. The overall frequency of tSAB deployment in side-impact crashes was found to be 8.1%. In the multivariate analysis, elderly age, near-side impact, colliding with fixed objects, non-oblique force, and higher crush extent were found to be factors associated with higher thoracic injuries (Abbreviated Injury Scale ≥ 2). MVOs in crashes with tSAB deployment were at an increased risk of injury compared with MVOs in crashes with no deployment, but no statistical difference was observed [adjusted odds ratios (AORs): 1.65 (0.73-3.73)]. Further, the incidence of lung injury and rib fractures increased with tSAB activation (p < 0.05). These results demonstrate the limited capability of tSABs in preventing thoracic injuries in motor vehicle crashes.

Breadth of use of The Abbreviated Injury Scale in The National Trauma Data Bank bank

OBJECTIVE

The Abbreviated Injury Scale (AIS) is an anatomic-based injury coding system that strives to provide sufficient detail to differentiate unique injuries for the purposes of research and quality assurance, while limiting the total number of codes to facilitate efficient use. It has been shown that a substantial portion of codes are unused in automotive-trauma specific databases. The goal of this study was to determine the percentage of codes utilized in a nationwide trauma registry that includes multiple mechanisms of injury. Secondary objectives were to examine unused codes and determine the number of codes that were most frequently utilized.

METHODS

Data were obtained from the National Trauma Data Bank (NTDB) years 2016 and 2017. All injury data were recorded using AIS version 2005 update 2008 (AIS08), which contains 1,999 distinct injury codes. The percentage of the total number of AIS08 codes used in NTDB were determined for each year individually and the combination of both years. The unused codes were then examined manually to identify common characteristics. Finally, the number of codes that provided 95% coverage of all recorded injuries was calculated.

RESULTS

There were 6,661,110 injuries recorded for 1,953,775 patients in NTDB over the two-year period. A small percentage of codes had an incorrect severity level (0.07%) or an incorrect injury code (0.0002%). There were 1,987 (99.4% of the entire AIS dictionary) unique AIS08 codes utilized in each year, with the unused codes varying between years. The unused codes tended to involve specific nerves, dural sinuses, or severe, bilateral injuries. During the combined two-year period, 1,996 (99.8% of the entire dictionary) unique AIS08 codes were used. Although almost every code was used at least once, 95% of the injuries in NTDB used only the 631 (31.6%) most frequent AIS08 codes.

CONCLUSIONS

In contrast to automotive specific databases, nearly all the AIS08 codes are used each year in the NTDB. Over a two-year period, only three AIS08 injuries were unused. However, less than a third of AIS08 codes encompass 95% of the injuries. Further research is necessary to determine if common codes should be separated into multiple distinct codes to enhance discriminatory ability of AIS.

The use of machine learning for investigating the role of plastic surgeons in anatomical injuries: A retrospective observational study

While plastic surgeons have been historically indispensable in the reconstruction of posttraumatic defects, their role in trauma centers worldwide has not been clearly defined. Therefore, we aimed to investigate the contribution of plastic surgeons in trauma care using machine learning from an anatomic injury viewpoint. We conducted a retrospective study reviewing the data for all trauma patients of our hospital from March 2019 to February 2021. In total, 4809 patients were classified in duplicate according to the 17 trauma-related departments while conducting the initial treatment. We evaluated several covariates, including age, sex, cause of trauma, treatment outcomes, surgical data, and severity indices, such as the Injury Severity Score and Abbreviated Injury Scale (AIS). A random forest algorithm was used to rank the relevance of 17 trauma-related departments in each category for the AIS and outcomes. Additionally, t test and chi-square test were performed to compare two groups, which were based on whether the patients had received initial treatment in the trauma bay from the plastic surgery department (PS group) or not (non-PS group), in each AIS category. The department of PS was ranked first in the face and external categories after analyzing the relevance of the 17 trauma-related departments in six categories of AIS, through the random forest algorithm. Of the 1108 patients in the face category of AIS, the PS group was not correlated with all outcomes, except for the rate of discharge to home (P < .0001). Upon re-verifying the results using random forest, we found that PS did not affect the outcomes. In the external category in AIS, there were 30 patients in the PS group and 56 patients in the non-PS group, and there was no statistically significant difference between the two groups when comparing the outcomes. PS has contributed considerably to the face and external regions among the six AIS categories; however, there was no correlation between plastic surgical treatment and the outcome of trauma patients. We investigated the plastic surgeons' role based on anatomical injury, using machine learning for the first time in the field of trauma care.

A quantitative analysis of trauma patients having undergone plastic surgery

Purpose

While plastic surgeons have been historically indispensable in reconstruction of posttraumatic defects, their role in Level I trauma centers around the world has not yet been clearly approved. This study aims to assess the contribution of plastic surgeons in major trauma care by evaluating the characteristics of trauma patients underwent plastic surgery at a Level I trauma center.

Method

From November 2014 to October 2020, we conducted a retrospective review of our hospital’s Trauma Registry System for patients with an Injury Severity Score (ISS) of 9 or higher. Of all of 7174 patients, the plastic surgery (PS) department treated 870 patients; the 6304 patients not treated by the PS were classified as the Non-PS. Then, we performed propensity score matching to reduce the statistical bias, after the death in the emergency room and the missing value were considered exclusion criteria.

Result

The mean ISS showed no significant difference between two groups (16.29 ± 7.04 in the PS vs. 16.68 ± 9.16 in the Non-PS, p = 0.3221). According to investigate the Abbreviated Injury Scale, both head and neck (65.0%) and face (46.4%) categories showed significantly higher in the PS group than the Non-PS group (p < 0.0001), and its contribution ratio was 2.151 and 21.822 times, respectively.

Conclusion

This study revealed the specialty of plastic surgery was face area in trauma care. We thus argue that plastic surgical care is imperative for trauma patients, and expect to be implicated in trauma system planning.

Age-based differences in the disability of spine injuries in pediatric and adult motor vehicle crash occupants

OBJECTIVE

The objective was to develop a disability-based metric for quantifying disability rates as a result of motor vehicle crash (MVC) spine injuries and compare functional outcomes between pediatric and adult subgroups.

METHODS

Disability rate was quantified using Functional Independence Measure (FIM) scores within the National Trauma Data Bank-Research Data System for the top 95% most frequent Abbreviated Injury Scale (AIS) 3 spine injuries (14 unique injuries). Pediatric (7-18 years), young adult (19-45 years), middle-aged adult (46-65 years), and older adult (66+ years) MVC occupants with FIM scores available and at least one of the 14 spine injuries were included. FIM scores of 1 or 2 at time of discharge were used to define disability and correspond to full functional or modified dependence in self-feeding, locomotion, and/or verbal expression. Disability rate was evaluated on a per injury basis for each AIS 3 spine injury and calculated as the proportion of cases associated with disability (i.e. FIM of 1 or 2) out of the total cases of that particular injury. Disability rates were calculated with and without the exclusion of cases with severe co-injuries (AIS 4+) to minimize bias from additional non-spinal injuries that could have contributed to disability. Associations between adjusted disability rates and existing mortality rates were investigated.

RESULTS

Locomotion impairment alone was the most frequent disability type for the top 14 AIS 3 spine injuries (7 cervical, 4 thoracic, and 3 lumbar) across all age groups and spine regions. Adjusted and unadjusted disability rates ranged from 0-69%. Adjusted disability rates increased with age: 14.8 ± 10% (mean ± SD) in pediatrics to 16.2 ± 6.6% (young adults), 29.2 ± 10.9% (middle-aged adults), and 45.0 ± 12.2% (older adults). Among all adult populations, adjusted mortality and disability rates were positively correlated (R²>0.24), with disability rates consistently greater than corresponding mortality rates.

CONCLUSIONS

Older adults had significantly greater disability rates associated with MVC spine injuries across all spinal regions. MVC disability rates for pediatrics were considerably lower. Overall, rates of mortality were significantly lower than rates of disability. The adjusted disability rates developed can supplement existing injury metrics by accounting for age- and location-specific functional implications of MVC spine injuries.

Basilar, skull and facial fractures in 2nd row occupants by crash type with a focus on side and rear impacts

OBJECTIVE

Field data was analyzed to assess the risk of basilar, skull and facial fractures in 2^nd row occupants by crash type. The study determined the rate of fractures in seriously injured (MAIS 3 + F) occupants to establish priorities for 2^nd row occupant safety.

METHODS

Field accident data on seriously injured (MAIS 3+) occupants was determined using 1993-2015 NASS-CDS and 2017-19 CISS by crash type identified with damage area variables for non-ejected occupants in the 2^nd row. Occupants with serious head and face injuries (AIS 3+) were subdivided by fractures to the skull, basilar skull and face. Moderate-to serious (AIS 2+) orbit fractures were included. The rate of injury was determined. Individual electronic cases were analyzed for occupants with basilar fracture in rear and side impacts.

RESULTS

The proportion of 2^nd row occupants with AIS 3+ head and face injury was highest at 73.7% in rear impacts followed by side impacts at 54.2% for those with MAIS 3 + F injury. Basilar fractures (AIS 3+) occurred in 53.9% of 2^nd row occupants with skull fracture in rear impacts but only 20.3% in side impacts. Overall, basilar fractures occurred in 10.8% of 2^nd row occupants with serious injury (MAIS 3 + F) in rear impacts and 2.7% in side impacts. The frequency of AIS 3+ facial fractures was highest in side impacts (40.2%) and lowest (7.6%) in rear impacts.

CONCLUSIONS

While basilar skull fractures are rare in 2^nd row occupants, at 0.083% in rear and 0.044% in side impacts, they represent 53.9% of 2^nd row occupants with a skull fracture and serious injury in rear impacts and 20.3% in side impacts. The mechanism of injury is different in rear and side impacts, but frequently involves multi-impact crashes, severe impacts, intrusion into the seating area and head impact on hard surfaces.

Road traffic accident-related thoracic trauma: Epidemiology, injury pattern, outcome, and impact on mortality—A multicenter observational study

Background

Thoracic trauma is a major cause of death in trauma patients and road traffic accident (RTA)-related thoracic injuries have different characteristics than those with non-RTA related thoracic traumas, but this have been poorly described. The main objective was to investigate the epidemiology, injury pattern and outcome of patients suffering a significant RTA-related thoracic injury. Secondary objective was to investigate the influence of serious thoracic injuries on mortality, compared to other serious injuries.

Methods

We performed a multicenter observational study including patients of the Rhône RTA registry between 1997 and 2016 sustaining a moderate to lethal (Abbreviated Injury Scale, AIS≥2) injury in any body region. A subgroup (AISThorax≥2 group) included those with one or more AIS≥2 thoracic injury. Descriptive statistics were performed for the main outcome and a multivariate logistic regression was computed for our secondary outcome.

Results

A total of 176,346 patients were included in the registry and 6,382 (3.6%) sustained a thoracic injury. Among those, median age [IQR] was 41 [25–58] years, and 68.9% were male. The highest incidence of thoracic injuries in female patients was in the 70–79 years age group, while this was observed in the 20–29 years age group among males. Most patients were car occupants (52.3%). Chest wall injuries were the most frequent thoracic injuries (62.1%), 52.4% of which were multiple rib fractures. Trauma brain injuries (TBI) were the most frequent concomitant injuries (29.1%). The frequency of MAISThorax = 2 injuries increased with age while that of MAISThorax = 3 injuries decreased. A total of 16.2% patients died. Serious (AIS≥3) thoracic injuries (OR = 12.4, 95%CI [8.6;18.0]) were strongly associated with mortality but less than were TBI (OR = 27.9, 95%CI [21.3;36.7]).

Conclusion

Moderate to lethal RTA-related thoracic injuries were rare. Multiple ribs fractures, pulmonary contusions, and sternal fractures were the most frequent anatomical injuries. The incidence, injury pattern and mechanisms greatly vary across age groups.

The use of head computerized tomography in patients with GCS 15 following trauma: Less is more

INTRODUCTION

Computerized tomography (CT) imaging is a standard part of traumatic brain injury (TBI) evaluation but not all patients require it after mild head injury. Given the increasing incidence of TBI in the United States, there is an urgent need to better characterize CT head imaging utilization in evaluating trauma patients, especially patients at low risk of requiring intervention, such as those presenting with a normal GCS.

METHODS

We analyzed the 2017-2019 National Trauma Databank using ICD-10 codes to identify patients who received a head CT. We used Abbreviated Injury Scale (AIS) scores to identify patients with a moderate to severe head injury defined as an AIS severity ≥ 3. Procedural TBI management was defined as having an intracranial monitor or operative decompression. We used a modified Poisson modeling to identify risk factors for a moderate/severe TBI and risk factors for undergoing procedural management among patients with head CT and GCS 15.

RESULTS

Of 2,850,036 patients, 1,502,039 (52.7%) had a head CT. Among patients who had a head CT, 1,078,093 patients (74.9%) had a GCS 15 on arrival. Of this group, only 16.6% (n = 176,431) had a moderate/severe head injury. For those with moderate/severe head injury, 6.0% (n = 10,544/176,431) of patients underwent procedural head injury management. Risk factors for undergoing procedural head injury management included: isolated head injury (RR 2.43, 95% CI 2.34, 2.53), male sex (RR 1.73, 95% CI 1.67, 1.80), age > 50 years (RR 1.39 95% CI 1.32, 1.47), falls (RR 1.28, 95% CI 1.22, 1.35), and the use of anti-coagulation (RR 1.16, 95% CI 1.11, 1.21).

CONCLUSION

Few patients had moderate/severe head injury when presenting with a GCS 15. However, patients ≥ 50 years, men, and those who suffered falls were at higher risk. Anti-coagulation use was not associated with moderate/severe head injury but did increase the risk of procedural TBI management. Given the cost and associated radiation, reducing CT utilization for younger patients while using a more liberal head CT strategy for high-risk patients may provide substantial patient value.

Evaluating the complex association between Social Vulnerability Index and trauma mortality

INTRODUCTION

Social determinants of health are known to impact patient-level outcomes, but they are often difficult to measure. The Social Vulnerability Index was created by the Centers for Disease Control to identify vulnerable communities using population-based measures. However, the relationship between SVI and trauma outcomes is poorly understood.

METHODS

In this retrospective study, we merged SVI data with a statewide trauma registry and used three analytic models to evaluate the association between SVI quartile and inpatient trauma mortality: (1) an unadjusted model, (2) a claims-based model using only covariates available to claims datasets, and (3) a registry-based model incorporating robust clinical variables collected in accordance with the National Trauma Data Standard.

RESULTS

We identified 83,607 adult trauma admissions from January 1, 2017, to September 30, 2020. Higher SVI was associated with worse mortality in the unadjusted model (odds ratio, 1.72 [95% confidence interval, 1.30-2.29] for highest vs. lowest SVI quintile). A weaker association between SVI and mortality was identified after adjusting for covariates common to claims data. Finally, there was no significant association between SVI and inpatient mortality after adjusting for covariates common to robust trauma registries (adjusted odds ratio, 1.10 [95% confidence interval, 0.80-1.53] for highest vs. lowest SVI quintile). Higher SVI was also associated with a higher likelihood of presenting with penetrating injuries, a shock index of >0.9, any Abbreviated Injury Scale score of >5, or in need of a blood transfusion (p < 0.05 for all).

CONCLUSION

Patients living in communities with greater social vulnerability are more likely to die after trauma admission. However, after risk adjustment with robust clinical covariates, this association was no longer significant. Our findings suggest that the inequitable burden of trauma mortality is not driven by variation in quality of treatment, but rather in the lethality of injuries. As such, improving trauma survival among high-risk communities will require interventions and policies that target social and structural inequities upstream of trauma center admission.

LEVEL OF EVIDENCE

Prognostic / Epidemiologic, Level IV.

Adult occupant injury risk in rear impact and frontal impact: Effect of impact conditions and occupant-related factors

OBJECTIVES

The objectives of this study were to compare the adult occupant injury risk on specific body regions in frontal and rear impact and to investigate the effect of those crash conditions and occupant-related factors on the injury risk.

METHOD

Data from the NASS-CDS and Crash Investigation Sampling System were studied for crashes during 2000 to 2019 involving model year 2000 to 2020 motor vehicles, including frontal collisions and rear-end collisions. The injury risk by specific body regions were compared by descriptive statistics, and logistic regression models were developed to examine the effects of various factors on injury risk by specific body regions, controlling for crash type (frontal impact and rear impact), vehicle impact speed, vehicle impact location, vehicle model year, and occupant gender, age, belt use, and seating position.

RESULTS

After controlling for the confounding factors, the occupants in frontal impact had higher overall injury risk than in rear impact (at Maximum Abbreviated Injury Scale [MAIS] 3+; odds ratio [OR] = 6.23; 95% confidence interval [CI] [6.06-6.40]), except for lower neck/spine injury risk at MAIS 1+ (OR = 0.47; 95% CI [0.46-0.47]). The impact speed (at MAIS 3+; OR = 1.10; 95% CI [1.10-1.10]) and aging (at MAIS 3+; OR = 1.05; 95% CI [1.05-1.05]) increase overall injury risk, and the unbelted occupants had higher overall injury risk than belted occupants not only in frontal impact (at MAIS 3+; OR = 4.04; 95% CI [3.98-4.10]), but also in rear impact (at MAIS 3+; OR = 28.4; 95% CI [26.4-30.5]). Females had higher overall injury risk than males in frontal impact (at MAIS 3+; OR = 2.01; 95% CI [1.99-2.04]) but not in rear impact (at MAIS 3+; OR = 0.77; 95% CI [0.73-0.81]).

CONCLUSIONS

Occupants in rear impact had lower injury risk than in frontal impact at MAIS 1+ to MAIS 3+, except for neck/spine at MAIS 1+. The belt restraint was effective not only in frontal impact but also in rear impact. This study provided injury risk references for current vehicles that may provide insight to the potential injury risk of rear-facing occupants in future vehicle configurations.

Patient-reported outcomes 6 to 12 months after isolated rib fractures: A nontrivial injury pattern

BACKGROUND

Despite the ubiquity of rib fractures in patients with blunt chest trauma, long-term outcomes for patients with this injury pattern are not well described.

METHODS

The Functional Outcomes and Recovery after Trauma Emergencies (FORTE) project has established a multicenter prospective registry with 6- to 12-month follow-up for trauma patients treated at participating centers. We combined the FORTE registry with a detailed retrospective chart review investigating admission variables and injury characteristics. All trauma survivors with complete FORTE data and isolated chest trauma (Abbreviated Injury Scale score of ≤1 in all other regions) with rib fractures were included. Outcomes included chronic pain, limitation in activities of daily living, physical limitations, exercise limitations, return to work, and both inpatient and discharge pain control modalities. Multivariable logistic regression models were built for each outcome using clinically relevant demographic and injury characteristic univariate predictors.

RESULTS

We identified 279 patients with isolated rib fractures. The median age of the cohort was 68 years (interquartile range, 56-78 years), 59% were male, and 84% were White. Functional and quality of life limitations were common among survivors of isolated rib fractures even 6 to 12 months after injury. Forty-three percent of patients without a preexisting pain disorder reported new daily pain, and new chronic pain was associated with low resilience. Limitations in physical functioning and exercise capacity were reported in 56% and 51% of patients, respectively. Of those working preinjury, 28% had not returned to work. New limitations in activities of daily living were reported in 29% of patients older than 65 years. Older age, higher number of rib fractures, and intensive care unit admission were independently associated with higher odds of receiving regional anesthesia. Receiving a regional nerve block did not have a statistically significant association with any patient-reported outcome measures.

CONCLUSION

Isolated rib fractures are a nontrivial trauma burden associated with functional impairment and chronic pain even 6 to 12 months after injury.

LEVEL OF EVIDENCE

Prognostic/epidemiologic, level III.

Settling the Score: Injury Severity Score Fails to Capture Nuances in Pediatric Trauma

OBJECTIVES

Recent work has questioned the accuracy of the Injury Severity Score (ISS) and the Abbreviated Injury Scale (AIS) in the pediatric population. We sought to determine mortality rates in pediatric trauma patients at ISSs considered "severe" in adults and whether mortality would vary substantially between adults and children sustaining injuries with the same AIS.

METHODS

Univariate logistic regression was used to generate mortality rates associated with ISS scores, for children (<16 years of age) and adults, using the 2016 National Trauma Data Bank. Mortality rates at an ISS of 15 were calculated in both groups. We similarly calculated ISS scores associated with mortality rates of 10%, 25%, and 50%. Receiver operating characteristic curves were constructed to compare the discriminative ability of ISS to predict mortality after blunt and penetrating injuries in adults and children. Mortality rates associated with 1 or more AIS 3 injuries per body region were defined.

RESULTS

There were 855,454 cases, 86,414 (10.1%) of which were children. The ISS associated with 10%, 25%, and 50% mortality were 35, 44, and 53, respectively, in children; they were 27, 38, and 48 in adults. At an ISS of 15, pediatric mortality was 1.0%; in adults, it was 3.1%. A 3.1% mortality rate was not observed in children until an ISS of 25. On receiver operating characteristic analysis, the ISS performed better in children compared with adults (area under the curve, 0.965 vs 0.860 [P < 0.001]). Adults consistently suffered from higher mortality rates than did children with the same number of severe injuries to a body region, and mortality varied widely between specific selected AIS 3 injuries.

CONCLUSIONS

Although the ISS predicts mortality well, children have lower mortality than do adults for the same ISS, and therefore, the accepted definition of severe injury is not equivalent between these 2 cohorts. Mortality risk is highly dependent on the specific nature of the injury, with large variability in outcomes despite identical AIS scores.

Mechanism and severity of mobility scooter-related injuries

OBJECTIVE

As a result of an aging population, mobility scooter use is increasing in Western countries. Consequently, an increase in mobility scooter-related injuries (MSRIs) is observed. Yet there is a paucity of studies in the literature assessing MSRIs. The purpose of this study was to investigate mechanism, severity, and localization of injury of MSRIs in the emergency department (ED) of a Dutch level 2 trauma center over a 9-year period.

METHODS

This was a retrospective study of MSRIs in the ED of a teaching hospital in the Netherlands between January 2010 and December 2019. All patients with an MSRI were included, as long as they were the driver of the vehicle. Data were collected from electronic patient files. The primary outcomes were severity of injury, defined by the Abbreviated Injury Scale (AIS) and Injury Severity Score (ISS), and mechanism and localization of injury.

RESULTS

A total of 382 patients were identified. Of these, 208 (54.3%) were female and the median age was 76 years (interquartile range [IQR] = 67.0-83.0). The median Charlson Comorbidity Index (CCI) was 5.0 (IQR = 4.0-6.0). Three (0.8%) patients had an ISS ≥ 16. The median ISS was 3.0 (IQR = 1.0-5.0). The lower extremity was the most commonly injured body region (46.5%), followed by head injury (36.3%), external injury (31.6%), and upper extremity injuries. Fractures were most commonly observed in the shoulder (10.2%), hip (8.9%), and ankle (6.3%). Most crashes were single-vehicle accidents (87.2%) and the most common mechanism of injury was rollover of mobility scooter (49.3%). Almost half of the patients (44.1%) had a fracture and the admission rate was 28.2% with a median length of stay (LOS) of 10 days. Fifty (13.1%) patients required surgery, of which 58% were hip repair surgery.

CONCLUSION

In this cohort of MSRIs, mobility scooter users had a median age of 76 years and severe comorbidity was common. Based on ISS, patients had a mild injury profile. However, the relatively high admission and surgery rates reflect the potential serious consequences of MSRIs and the obvious vulnerability of this population.

Quantifying injury severity for traumatic brain injury with routinely collected health data

BACKGROUND

Routinely collected health data (RCHD) offers many opportunities for traumatic brain injury (TBI) research, in which injury severity is an important factor.

OBJECTIVE

The use of clinical injury severity indices in a context of RCHD is explored, as are alternative measures created for this specific purpose. To identify useful scales for full body injury severity and TBI severity this study focuses on their performance in predicting these currently used indices, while accounting for age and comorbidities.

DATA

This study utilized an extensive population-based RCHD dataset consisting of all patients with TBI admitted to any Belgian hospital in 2016.

METHODS

Full body injury severity is scored based on the (New) Injury Severity Score ((N)ISS) and the ICD-based Injury Severity Score (ICISS). For TBI specifically, the Abbreviated Injury Scale (AIS) Head, Loss of Consciousness and the ICD-based Injury Severity Score for TBI injuries (ICISS) were used in the analysis. These scales were used to predict three outcome variables strongly related to injury severity: in-hospital death, admission to intensive care and length of hospital stay. For the prediction logistic regressions of the different injury severity scales and TBI severity indices were used, and error rates and the area under the receiver operating curve were evaluated visually.

RESULTS

In general, the ICISS had the best predictive performance (error rate between 0.06 and 0.23; AUC between 0.82 [0.81;0.83] and 0.86 [0.85;0.86]). A clearly increasing error rate can be noticed with advancing age and accumulating comorbidity.

CONCLUSION

Both for full body injury severity and TBI severity, the ICISS tends to outperform other scales. It is therefore the preferred scale for use in research on TBI in the context of RCHD. In their current form, the severity scales are not suitable for use in older populations.

Injury risks and crashworthiness benefits for females and males: Which differences are physiological?

OBJECTIVE

Previous research has found elevated injury risk for females relative to males in passenger vehicle crashes but has not accounted for ways the crashes themselves differ between these populations. Vehicle curb weight, ride height, safety rating, airbag deployment, and crash configuration all influence injury outcome and often are not well-represented by delta-V alone. This study evaluated the effect of occupant sex on injury risk in front and side crashes while limiting or controlling for non-physiological crash differences. Additionally, the effects of crashworthiness improvements are compared for females and males.

METHODS

NASS-CDS cases from 1998-2015 calendar years involving a belted driver in a front crash or a struck-side driver or right front passenger in a side crash were analyzed. Case vehicle model years were 1989-2016. Logistic regression was used to estimate the risk of MAIS ≥ 2 and MAIS ≥ 3 injury outcomes for females relative to males as well as the change in risk due to improved crashworthiness. Sex-based differences in occupant age, mass, and stature; crash test rating; delta-V; crash configuration; and vehicle-to-vehicle compatibility were considered either through case selection or the inclusion of additional regression covariates.

RESULTS

Before controlling for crash and vehicle differences, female drivers in front crashes had higher estimated overall and body-region-specific risks of MAIS ≥ 2 and MAIS ≥ 3 injury, as consistent with previous findings. After accounting for such differences, all ratios of injury odds for females relative to males were reduced. Females remained at higher risk of MAIS ≥ 2 injury (OR, 2.23; 95% CI, 1.42-3.51), especially extremity injury, but had similar odds for MAIS ≥ 3 non-extremity injury (OR, 0.98; 95% CI, 0.56-1.7). While controlling for crash differences in side impacts, none of the estimated injury risk differences by sex were significant at the p ≤ 0.05 level. Estimated benefits of improved crashworthiness were similar or greater for females than for males for most injury outcomes.

CONCLUSIONS

Female-specific crashworthiness improvements may be required to provide additional protection against AIS 2 extremity injury. Much of the remaining discrepancy in sex-based injury risk can be attributed differences between vehicles and crashes, not to physiological differences. Addressing these differences will require other types of countermeasures.

Motorcyclist injuries: Analysis of German in-depth crash data to identify priorities for injury assessment and prevention

Globally there are more than 350,000 PTW fatalities each year. Safety concepts to protect Powered Two-Wheeler (PTW) riders exist and are being developed further, but they need appropriate procedures and test tools (Anthropometric Test Devices (ATDs) for physical testing and Human Body Models (HBMs) for virtual testing) to direct and promote those developments. To aid further development of the tools, we aim to rank the frequency of specific injuries arising from the prevalent impact types, discuss how current ATDs and HBMs are equipped to assess these injuries, and suggest what further development should be prioritized. We analyzed a sample of injured riders from the German In-depth Accident Study (GIDAS) according to the Abbreviated Injury Scale (AIS) 2015 classification, using severity thresholds of at-least-moderate (AIS2+) and at-least-serious (AIS3+). PTW rider injuries were ranked by frequency for all crashes and also for sub-samples of specific impact types (impact with passenger cars, ground, and roadside furniture). The most frequent AIS3+ injuries were: femur fracture (17%), rib cage fracture (13%), lung injury (9%), tibia fracture (7%), and cerebrum injury (7%). In all impacts together and as for impacts with the road surface, injuries to the thorax were most frequent. In impacts with cars and road furniture, thorax injuries were also frequent, but outranked by lower extremity injuries. Considering both AIS2+ and AIS3+ injuries, the priorities for PTW rider safety interventions are: fracture of the rib cage, femur fracture, tibia fracture, radius fracture, cerebrum injury, and cerebral concussion. The ATD currently used most frequently, the Hybrid III, is unlikely to provide adequate rib fracture injury assessments, but HBMs are promising in this area. Rib injury assessment may also reasonably predict other injuries that were correlated or in proximity to rib fractures: clavicle, lung, and upper abdomen organ injury. Lower extremity, upper extremity, and head injuries are likely addressable to some extent with current ATDs while HBMs hold the promise of more detailed and mechanism-specific injury assessments. Both ATDs and HBMs need more validation for use in the PTW environment.

Acute intensive care unit resuscitation of severely injured trauma patients: Do we need a new strategy?

BACKGROUND

Unlike recent advances in blood product resuscitation, intravenous crystalloid (IVF) use after intensive care unit (ICU) admission in hemorrhagic shock has received less attention and current recommendations are based on limited evidence. To address this knowledge gap, we aimed to determine associations between IVF administration during acute ICU resuscitation and outcomes. We hypothesized that larger IVF volumes are associated with worse outcomes.

METHODS

We linked our trauma registry with electronic health record data (2012-2015) to identify adults with an initial lactate level of ≥4 mmol/L and documented lactate normalization (≤2 mmol/L), excluding those with isolated head Abbreviated Injury Scale score ≥3. We focused on the period from ICU admission to lactate normalization, analyzing duration, volume of IVF, and proportion of volume as 1-L boluses. We used linear regression to determine associations with ICU length of stay and duration of mechanical ventilation in survivors, and logistic regression to identify associations with acute kidney injury and home discharge while adjusting for important covariates.

RESULTS

We included 337 subjects. Median time to lactate normalization was 15 hours (interquartile range, 7-25 hours), and median IVF volume was 3.7 L (interquartile range, 1.5-6.4 L). The fourfold difference between the upper and lower quartiles of both duration and volume remained after stratifying by injury severity. Hourly volumes tapered over time but persistently aggregated at 0.5 and 1 L, with 167 subjects receiving at least one 0.5-L bolus for 6 hours after ICU admission. Administration of larger volumes was associated with longer ICU length of stay and duration of mechanical ventilation, as well as acute kidney injury.

CONCLUSION

There is substantial variation in volume administered during acute ICU resuscitation, both absolutely and temporally, despite accounting for injury severity. Administration of larger volumes during acute ICU resuscitation is associated with worse outcomes. There is an opportunity to improve outcomes by further investigating and standardizing this important phase of care.

LEVEL OF EVIDENCE

Therapeutic/care management, level IV.

Trampoline Injuries in a Statewide Trauma System

INTRODUCTION

It is well known that trampolines can be a particular source of danger, especially in children. We sought to examine the profile of those patients with trampoline injuries. We hypothesized there would be certain injury patterns predicative of trampoline injuries.

METHODS

All patients submitted to Pennsylvania Trauma Outcome Study database from 2016 to 2018 were analyzed. Trampoline injury was determined by ICD-10 activity code. Injury patterns in the form of abbreviated injury scale body regions were examined. Patient demographics and clinical variables were compared between those with trampoline injury vs those without.

RESULTS

There were 107 patients with a trampoline injury. All of these patients were discharged alive and had a blunt mechanism of injury. The most common injury type was injury to the extremities (n=90,[84.1%]) with 54(50.5%) upper extremity injuries and 36(33.6%) lower extremity injuries. Ten (9.35%) patients had injury to the spine and five (4.67%) had head injury. Those with trampoline injuries were significantly younger (13y vs. 48.6y) and more likely to be white or of Hispanic ethnicity. Almost half of the patients injured (49.5%) were under 10 years. Patients with trampoline injuries had significantly lower Injury Severity Scores and significantly higher shock index.

DISCUSSION

The majority of patients with trampoline injuries had injury to an extremity. These results help better understand the demographic, physiologic, and anatomic patterns surrounding trampoline injuries. Current government standards recommend that no child under age six should use a full-sized trampoline; however, based of this study, we advise that this age be increased to ten.

Belt-induced abdominal injuries in recent frontal impact CIREN cases

OBJECTIVE

The objective is to report sex-related variation in 3-point belt-related abdominal injuries in Crash Injury Research Engineering Network (CIREN) cases.

METHODS

A query of CIREN cases was made for those with the highest ranked Collision Deformation Classification (CDC) to the front plane, a principal direction of force (PDOF) ±20° from 0°, and Abbreviated Injury Scale (AIS) 2+ abdomen injuries attributed to the seat belt. Patterns of injury were categorized as above the crest of the ilium, injuries below the crest of the ilium, and injuries above and below the ilium. This was done in the context of autonomous vehicle occupant kinematics testing results. Twelve 5th and 95th percentile 3-point belt-restrained postmortem human subjects were subjects; test speeds and recline angles varied. Abdomen injuries were anticipated; none were observed.

RESULTS

Thirty-five occupants with belt-related abdominal injuries were identified. Seventeen case occupants sustained an injury only within the pelvic contents: 5 women and 12 men. Nine of the 17 were at or above the 81st percentile for height, 13 were between the 62nd and 80th percentile for height, and 4 were less than the 50th percentile for height.

CONCLUSIONS

The stature component of the body mass index (BMI) appears to be a plausible candidate for an independent variable that is a contributing factor explaining the incidence of pelvic contents injuries when a 3-point belt-restrained occupant is involved in a frontal impact.

Deflection-based parametric survival analysis side impact chest injury risk curves AIS 2015

OBJECTIVES

The objective of this study was to reanalyze lateral postmortem human surrogate (PMHS) sled test chestband data to construct updated lateral thoracic injury risk curves (IRCs) using survival analysis.

METHODS

Chestband and injury data were gathered from 16 previously conducted PMHS sled tests. Briefly, 2 chestbands were wrapped around the thorax's circumference at the levels of ribs 4 and 8. Tests were conducted at 6.7 m/s on a rigid and padded load wall fixed to the top of a rebound sled. The injuries were reclassified using the Abbreviated Injury Scale (AIS) 2015 coding scheme. Chestband signals were combined with pretest specimen measurements to calculate the chest deflection contour time history. Deflections were determined using updated processing techniques calculating the change in length of every point on the contour from the impacted side using the thorax's midpoint as the origin. Four candidate metrics were selected: the deflection from rib 4, the deflection from rib 8, the greater of the deflections from ribs 4 and 8, and the average of the deflections from ribs 4 and 8. AIS 3+ IRCs were developed considering outcomes of AIS ≥3 injuries. All injury data were uncensored, and noninjury data were right-censored. Three specimen mass-based IRCs were determined using the IRC with the lowest Brier score metric (BSM): The first corresponded to the 5th percentile female mass (49 kg), the second to the 50th percentile male mass (77 kg), and the third to the average mass of the PMHS ensemble (65 kg).

RESULTS

Sixteen PMHS were used in the current study. Six specimens were right-censored, and 10 were uncensored. The average metric had the lowest BSM, and mass was a significant covariate with 50% risk of AIS3+ injury at 72mm of chest deflection. The 50% risk deflection magnitudes for the 5th percentile female (49 kg), 50th percentile male (77 kg), and PMHS ensemble (PMHS-E) (65 kg) were 59, 81, and 71 mm. IRCs for the 4 metrics and the 3 occupant masses are given.

CONCLUSIONS

IRCs were developed using survival analysis, and the average of the peak deflections was found to best represent the thoracic chest deflection response. Mass-based side impact IRCs were calculated for occupants representing the WorldSID 5th percentile female and 50th percentile male anthropomorphic test device.

Brain injury severity due to direct head contact from near-side motor vehicle collisions

OBJECTIVE

The objective of this study was to generate functional forms of brain injury risk curves using the National Automotive Sample System Crashworthiness Data System's (NASS-CDS) database for the years of 2001-2015. The population of interest was near-side occupants who experienced a direct head impact with an injury source located lateral to a typical seated position.

METHODS

Brain injuries were restricted to Abbreviated Injury Scale (AIS) 2005 Update 2008 defined concussions and internal organ injuries of the head. Near-side occupants comprised two major groups, both of which were required to have evidence of head contact (i.e., a head injury with DIRINJ = 1 and SOUCON = 1 or 2): brain injured occupants (MAIS1, MAIS2, MAIS3+) and non-brain injured occupants with some other direct contact head injury (MAIS0). Analyzed cases were required to have an indication of a reasonable crash reconstruction. Injury sources allowed within the final sample consisted of A-pillars, B-pillars, roof/roof rails, impacting vehicles/exterior objects, other components of the vehicle's side interior, and other occupants or otherwise unspecified interior objects. Risk curves for occupants with brain injury severities of MAIS0, MAIS1+, MAIS2+, and MAIS3+ were generated using multivariate stepwise logistic regressions. Investigated predictors involved vehicle change in velocity, seat belt use, principal direction of force (PDOF), and injury source type (B-pillar and side window).

RESULTS

Multivariate stepwise logistic regressions identified significant predictors of lateral change in velocity (dvlat) for all injury severity categories, and side window injury source (INJSOU = 56, 57, 58, 106, and 107) for MAIS0 and MAIS1+ risk curves. Although model sensitivity decreased for more severe injury predictions, risk curves dependent on only dvlat yielded accuracies of 70% for all presented models.

CONCLUSIONS

Real world crashes are often complex and lack the benefit of real time monitoring; however, NASS-CDS post-crash investigations provide data useful for injury risk prediction. Further analysis is needed to determine the effect of data confidence, injury source, and accident sequence restrictions on NASS-CDS sampling biases. The presented models likely favor a more conservative risk prediction due to the limitations of NASS-CDS data collection, AIS code conversion, and unweighted sample analysis.

Travel speed and the risk of serious injury in vehicle crashes

While there is a large quantity of prior research on speed and road safety, no previous studies have quantified the absolute risk of serious injury in a crash relative to travel speed. This study aimed to produce risk curves that relate travel speed to the risk of serious injury in light vehicle impacts in order to contribute to the process of selecting acceptable travel speeds. Serious injury was defined in this study as any injury having a maximum abbreviated injury scale (MAIS) of three or greater, or a fatal injury (MAIS3+F). In the context of a crash, travel speed is defined as the vehicle's speed before the driver reacts to the crash situation. Travel speed was determined by selecting the highest pre-impact speed recorded by an Event Data Recorder (EDR) in the seconds before the crash. A total of 1,618 light vehicle impacts were analysed using logistic regression. Individual risk curves were produced for front, head on, side, rear and single vehicle impacts. The analysis found significant positive relationships between the risk of serious injury and travel speed for all of these impact types. The travel speeds at which the risk of serious injury reached one per cent were 63 km/h across all impacts, 17 km/h for head on impacts, 48 km/h for single vehicle impacts, 58 km/h for side impacts, 81 km/h for front impacts and 96 km/h for rear impacts. These results have implications for the setting of speed limits and other measures that influence the speed at which vehicles travel.

Odds ratios for reclined seating positions in real-world crashes

It is widely believed that with higher levels of vehicle automation and especially with the advent of fully automatic vehicles, the currently typical forward-facing, upright position will give way to a more relaxed and reclined seating posture. Therefore, the current study investigates the influence of a reclined sitting position on crash injury severity by analyzing real-world crash data from the German in-depth accident study (GIDAS). We compared reclined to upright occupants and focused on effect sizes regarding odds ratios at different injury severity levels. We used the abbreviated injury scale (AIS 2015) for injury scaling and the maximum AIS (MAIS) at the levels 2+, 3+, and 4+ to convert injury severity into a dichotomous metric. Two different analyses were conducted, one looking at the occupant MAIS and one focusing on selected body regions. The body regions investigated are head/face/neck (HFN), thorax, abdomen, pelvis/hip/lower extremities (PHL), and upper extremities. We computed odds ratios greater than one indicating a higher odds of injury at a given injury severity level in the reclined group compared to the upright group. The odds ratios for belted, reclined occupants compared to belted, upright sitting occupants are 2.07, 3.09, and 3.66 for the injury severity levels MAIS2+, MAIS3+, and MAIS4+, respectively. When looking at the body regions, the spread of the odds ratios is wider: At the MAIS2+ level, the odds ratios range between 1.6 and 7.1; at the MAIS3+ level, the odds ratios span from 1.5 to 8.7, with the latter value representing the PHL region. No odds ratio could be computed for the upper extremity injuries at this level. At the MAIS4+ injury severity level, only the HFN odds ratio was statistically significant with a value of 5.6. This study is among the first to show an association between body posture and injury severity at MAIS3+ and MAIS4+ injury level in real-world crashes for reclined seating postures.

Principles and Methods for Evidence-Based Quantification of the Effect of Seat Belt Non-Use in Crash-Related Litigation

Traffic crashes are a common cause of injury and death, and often result from the negligent actions of an inattentive, speeding, or impaired driver. In such cases, a civil legal action may be brought by an injured claimant for compensation for injuries resulting from a crash. Crash-related litigation is defended on various theories, one of which is to raise the issue of contributory negligence when the claimant was not using an available seat belt at the time of the crash, based on the assertion that the claimed injuries would have been avoided or minimized to some degree if the claimant had been restrained. At present, there are no published standards or systematic approach for assessing and quantifying the contribution of seat belt non-use to the cause of a claimant’s specific injury. A reliable medicolegal analysis that addresses whether contributory negligence can be proven in a specific case requires a multidisciplinary approach: First, the nature and severity of the crash must be reconstructed as it affected the vehicle kinetics (engineering) and in turn affected the kinematics of the occupant (biomechanics), next, the injuries must be described and scaled for severity (medicine/pathology), and finally, the risk of the known injuries given the actual circumstances of the crash and occupant (i.e., unbelted) are compared to the risk of the same injuries, and the same crash circumstances, but in the hypothetical scenario in which the claimant is belted. In the present discussion, methods for analyzing the presence and quantifying the degree of contributory negligence for seat belt non-use, suitable for presentation in a medicolegal setting, are described and illustrated with an example from the author’s personal case inventory. A detailed reconstruction of the crash is described, along with the associated occupant kinematics, and the resulting observed injuries. The injuries are then categorized by their anatomical location, type, and severity using Abbreviated Injury Scale designations. Quantification of the injury risk for the actual (unbelted) vs. hypothetical (belted) scenario is based on case-specific analysis of data accessed from a US national crash injury database The difference in risk for the two exposure scenarios can be quantified in terms of either relative risk (a risk ratio) or attributable risk (a risk proportion), with the goal to determine whether the analysis meets the threshold of a relative risk of >2.0, or an attributable risk of 50%, in order to meet the “more probable than not” standard typically required by courts. As a final step in a reliable analysis that exceeds the legal threshold for relevant evidence, the absolute increase in risk is used to quantify the degree to which the claimant’s seat belt non-use contributed to the likelihood of their injuries.