Estimating the number of traffic crash-related cervical spine injuries in the United States; An analysis and comparison of national crash and hospital data

The Influence of "Labels" for Neck Pain on Recovery Expectations Following a Motor Vehicle Crash: An Online-Randomized Vignette-Based Experiment

OBJECTIVES: To (1) investigate whether different labels for neck pain after a motor vehicle crash (MVC) influenced recovery expectations and management beliefs, (2) explore reasons for low recovery expectations and greater likelihood for lodging a claim, and (3) explore the moderating effect of neck pain history and sociodemographic characteristics. DESIGN: Online randomized experiment with nested qualitative content analysis. METHODS: We randomized 2229 participants from the general population (mean age: 46.7 ± 17.5 years; 72.4% females; 66% with previous or current neck pain; 10% with an MVC experience) to read 1 of 5 scenarios describing a patient with neck pain after an MVC, each was labeled as whiplash injury, whiplash-associated disorder, posttraumatic neck pain, neck pain, or neck strain. The primary outcome was recovery expectations, rated on a 0- to 10-point scale. RESULTS: Participants allocated to whiplash-associated disorder or neck pain had lower recovery expectations than those allocated to neck strain (adjusted mean difference [95% confidence interval]: -0.5 [-0.9 to -0.1] for both comparisons). Whiplash-associated disorder led to more recovery uncertainty, while neck pain led to greater doubt about the health care provider. Most secondary outcomes showed significant but small differences. Participants allocated to neck strain were less inclined to claim than those allocated to whiplash-associated disorder or whiplash injury due to less perceived need for financial support. Neck pain history moderated labeling effects on recovery expectations; household income moderated the claim intention. CONCLUSIONS: Labels for neck pain after an MVC influenced recovery expectations and management preferences. The clinical relevance of the small effects was unclear. J Orthop Sports Phys Ther 2024;54(11):1-10. Epub 5 September 2024. doi:10.2519/jospt.2024.12590.

Mechanisms and risk factors associated with spinal cord injury, facet fracture, and level of dislocation, in occupants with cervical spine dislocations sustained in motor vehicle crashes

OBJECTIVE

Motor vehicle crashes (MVCs) are the leading cause of cervical spine dislocation. The mechanisms underlying this injury are unclear, limiting the development of injury prevention devices and strategies. MVC databases contain occupant, medical, vehicle, and crash details that are not routinely collected elsewhere, providing a unique resource for investigating injury mechanisms and risk factors. In this study, a comprehensive standalone analysis of cervical spine dislocations captured in MVC databases was performed.

METHODS

Epidemiologic, biomechanical, and injury data were extracted from three MVC databases. Logistic regression models were developed to determine the occupant, vehicle, and crash characteristics, as well as the global (inertial or impact) and regional (flexion, compression, etc.) loading mechanisms associated with the level of cervical spine dislocation (axial or sub-axial), and the occurrence of spinal cord injury (SCI) or facet fracture concomitant to dislocation.

RESULTS

There was no association between global or regional injury mechanisms and the level of cervical spine dislocation. Sub-axial dislocations were typically due to head/face impact with the airbag or upper interior components, or a result of seatbelt restraint of the torso. Higher occupant age, lower BMI, partial/no ejection, and frontal and side configuration crashes (compared to rollovers) were associated with a higher likelihood of sub-axial, versus axial, dislocation. Amongst all dislocations, an increased likelihood of SCI was associated with impact injuries, airbag non-deployment, and complete ejection, while concomitant facet fracture was associated with the presence of regional compression. Severe crashes, partial ejections, and "utility vehicles" and "vans and trucks" (compared with "passenger vehicles") were associated with a higher risk of facet fracture concomitant to sub-axial dislocation.

CONCLUSION

The findings of this study may be used to inform the loading modes to be simulated in future ex vivo or computational models seeking a better understanding of cervical spine dislocations.

Traumatic spinal injury-related hospitalizations in the United States, 2016-2019: a retrospective study

BACKGROUND

Traumatic spinal injury (TSI) is associated with significant fatality and social burden; however, the epidemiology and treatment of patients with TSI in the US remain unclear.

MATERIALS AND METHODS

An adult population was selected from the National Inpatient Sample database from 2016 to 2019. TSI incidence was calculated and TSI-related hospitalizations were divided into operative and nonoperative groups according to the treatments received. TSIs were classified as fracture, dislocation, internal organ injury, nerve root injury, or sprain injuries based on their nature. The annual percentage change (APC) was calculated to identify trends. In-hospital deaths were utilized to evaluate the prognosis of different TSIs.

RESULTS

Overall, 95 047 adult patients were hospitalized with TSI in the US from 2016 to 2019, with an incidence rate of 48.4 per 100 000 persons in 2019 (95% CI: 46.2-50.6). The total incidence increased with an APC of 1.5% (95% CI: 0.1-3%) from 2016 to 2019. Operative TSI treatment was more common than nonoperative (32.8 vs. 3.8; 95% CI: 32.3-33.2 vs. 3.6-4%). The number of operations increased from 37 555 (95% CI: 34 674-40 436) to 40 460 (95% CI: 37 372-43 548); however, the operative rate only increased for internal organ injury (i.e. spinal cord injury [SCI])-related hospitalizations (APC, 3.6%; 95% CI: 2.8-4.4%). In-hospital mortality was highest among SCI-related hospitalizations, recorded at 3.9% (95% CI: 2.9-5%) and 28% (95% CI: 17.9-38.2%) in the operative and nonoperative groups, respectively.

CONCLUSIONS

The estimated incidence of TSI in US adults increased from 2016 to 2019. The number of operations increased; however, the proportion of operations performed on TSI-related hospitalizations did not significantly change. In 2019, SCI was the highest associated mortality TSI, regardless of operative or nonoperative treatment.

Objectively and subjectively measured physical activity levels in individuals with whiplash associated disorder and aged-matched healthy controls

BACKGROUND

Whiplash associated disorders (WAD) are the most common non-hospitalised injuries resulting from a motor vehicle crash. Half of individuals with WAD experience ongoing pain and disability. Furthermore, individuals with persistent WAD have lower levels of aerobic capacity and isometric strength compared with age-matched controls. It is not known whether these differences are associated with increased levels of pain and disability, or with reduced physical activity (PA) participation.

OBJECTIVE

Our primary aim was to compare PA levels in individuals with persistent WAD with healthy controls. Secondary aims were to: compare objective and subjective measurements of PA; explore factors that may influence PA; and describe proportions of these populations meeting World Health Organisation PA guidelines.

METHODS

Objective (ActiGraph accelerometer; seven days) and subjective (International Physical Activity Questionnaire (IPAQ)) PA data were collected for n = 53 age-matched participants (WAD n = 28; controls n = 25).

RESULTS

Independent sample t-tests showed no significant difference in objectively measured PA (p>0.05) between WAD and controls. For the subjective measure (IPAQ), controls reported more overall weekly PA (t = 0.219, p<0.05), while WAD participants reported more weekly walking minutes (t = -0.712, p<0.05). Linear regression showed mental health quality-of-life predicted objectively measured moderate intensity PA (R2 = 0.225, F (2, 44) = 6.379, p<0.004) and subjectively reported overall PA (R2 = 0.132, F (1, 41) = 6.226, p<0.017). Bland-Altman analyses indicated that subjects over-reported MVPA and under-reported sedentary time using the IPAQ.

CONCLUSIONS

Individuals with WAD had levels of physical and mental health quality-of-life significantly lower than controls and below population norms yet participated in similar levels of PA. Given that increased perceptions of mental health quality-of-life were positively associated with objectively measured MVPA and subjectively reported overall PA, strategies to help people with WAD achieve adequate doses of MVPA may be beneficial. ActiGraph-measured and IPAQ-reported PA were discordant. Hence, IPAQ may not be a reliable measure of habitual PA in WAD.

Effect of muscle activation scheme in human head-neck model on estimating cervical spine ligament strain from military volunteer frontal impact data

Cervical spine (c-spine) injuries are a common injury during automobile crashes. The objective of this study is to verify an existing head-neck (HN) finite element model with military volunteer frontal impact kinematics by varying the muscle activation scheme from previous literature. Proper muscle activation will allow for accurate percent elongation (strain) of the c-spine ligaments and will serve to establish ligamentous response during non-injury frontal impacts. Previous human research volunteer (HRV) frontal impact sled tests reported kinematic data that served as the input for HN model simulation. Peak sled acceleration (PSA) was varied between 10G and 30G for HRVs. Muscle activation was shifted to begin at 0 ms at start of impact to allow for proper muscle contraction in the HN model. Then, extensor muscle activation magnitude was varied between 20 and 100% to determine the proper activation necessary to match kinematic outputs from the model with experimental results. The model was validated against 10G test recorded response. Ligament strain was measured from multiple ligaments along the c-spine once the model was verified. The 40% activated extensor muscle scheme was deemed the most biofidelic, with CORA scores of 0.743 and 0.686 for head X linear acceleration and angular Y acceleration for 10G pulse. All PSA groups scored well with this muscle activation. Most ligaments were buffered well by the active simulation, with only the interspinous ligament nearing physiologic injury. With the HN model verified against additional kinematic data, simulations with higher accelerations to predict areas of injury in real life crash scenarios are possible.

Spinal injury rates and specific causation in motor vehicle collisions

Motor vehicle collisions (MVCs) are a leading cause of acute spinal injuries. Chronic spinal pathologies are common in the population. Thus, determining the incidence of different types of spinal injuries due to MVCs and understanding biomechanical mechanism of these injuries is important for distinguishing acute injuries from chronic degenerative disease. This paper describes methods for determining causation of spinal pathologies from MVCs based on rates of injury and analysis of the biomechanics require to produce these injuries. Rates of spinal injuries in MVCs were determined using two distinct methodologies and interpreted using a focused review of salient biomechanical literature. One methodology used incidence data from the Nationwide Emergency Department Sample and exposure data from the Crash Report Sample System supplemented with a telephone survey to estimate total national exposure to MVC. The other used incidence and exposure data from the Crash Investigation Sampling System. Linking the clinical and biomechanical findings yielded several conclusions. First, spinal injuries caused by an MVC are relatively rare (511 injured occupants per 10,000 exposed to an MVC), which is consistent with the biomechanical forces required to generate injury. Second, spinal injury rates increase as impact severity increases, and fractures are more common in higher-severity exposures. Third, the rate of sprain/strain in the cervical spine is greater than in the lumbar spine. Fourth, spinal disc injuries are extremely rare in MVCs (0.01 occupants per 10,000 exposed) and typically occur with concomitant trauma, which is consistent with the biomechanical findings 1) that disc herniations are fatigue injuries caused by cyclic loading, 2) the disc is almost never the first structure to be injured in impact loading unless it is highly flexed and compressed, and 3) that most crashes involve predominantly tensile loading in the spine, which does not cause isolated disc herniations. These biomechanical findings illustrate that determining causation when an MVC occupant presents with disc pathology must be based on the specifics of that presentation and the crash circumstances and, more broadly, that any causation determination must be informed by competent biomechanical analysis.

Changing Care Settings for Injuries

Tracking injury rates is important for surveillance purposes but little data exist for injuries outside of emergency department visits. We assess the share and type of injuries reported in urgent care centers (UCCs) compared with other settings. We used FAIR Health claims data from 2016 through the first quarter of 2019 to calculate the percent of claims and most common types of injuries. Of the 197 million injury claims, 62% occurred in office settings and 17% in hospital outpatient departments (HOPDs), 5% in inpatient and in ED settings, and less than 2% in UCCs. Injury claims in UCCs increased 6% from 2016 to 2018, whereas injury claims in EDs declined 24%. Overall, physician offices and HOPDs accounted for the largest share of injury care, but UCCs represented the fastest growing setting to treat injuries.

Pregabalin vs placebo to prevent chronic pain after whiplash injury in at-risk individuals: results of a feasibility study for a large randomised controlled trial

ABSTRACT

There are few effective treatments for acute whiplash-associated disorders (WADs). Early features of central sensitisation predict poor recovery. The effect of pregabalin on central sensitisation might prevent chronic pain after acute whiplash injury. This double blind, placebo-controlled randomised controlled trial examined feasibility and potential effectiveness of pregabalin compared with placebo for people with acute WAD. Twenty-four participants with acute WAD (<48 hours) and at risk of poor recovery (pain ≥5/10) were recruited from hospital emergency departments in Queensland, Australia, and randomly assigned by concealed allocation to either pregabalin (n = 10) or placebo (n = 14). Pregabalin was commenced at 75 mg bd, titrated to 300 mg bd for 4 weeks, and then weaned over 1 week. Participants were assessed at 5 weeks and 3, 6, and 12 months. Feasibility issues included recruitment difficulties and greater attrition in the placebo group. For the primary clinical outcome of neck pain intensity, attrition at 5 weeks was pregabalin: 10% and placebo: 36% and at 12 months was pregabalin: 10% and placebo: 43%. Pregabalin may be more effective than placebo for the primary clinical outcome of neck pain intensity at 3 months (mean difference: -4.0 [95% confidence interval -6.2 to -1.7]) on an 11-point Numerical Rating Scale. Effects were maintained at 6 months but not 12 months. There were no serious adverse events. Minor adverse events were more common in the pregabalin group. A definitive large randomised controlled trial of pregabalin for acute whiplash injury is warranted. Feasibility issues would need to be addressed with modifications to the protocol.

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.

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.

Nanopharmaceutical-based regenerative medicine: a promising therapeutic strategy for spinal cord injury

Spinal cord injury (SCI) is a neurological disorder that can lead to loss of perceptive and athletic function due to the severe nerve damage. To date, pieces of evidence detailing the precise pathological mechanisms in SCI are still unclear. Therefore, drug therapy cannot effectively alleviate the SCI symptoms and faces the limitations of systemic administration with large side effects. Thus, the development of SCI treatment strategies is urgent and valuable. Due to the application of nanotechnology in pharmaceutical research, nanopharmaceutical-based regenerative medicine will bring colossal development space for clinical medicine. These nanopharmaceuticals (i.e. nanocrystalline drugs and nanocarrier drugs) are designed using different types of materials or bioactive molecules, so as to improve the therapeutic effects, reduce side effects, and subtly deliver drugs, etc. Currently, an increasing number of nanopharmaceutical products have been approved by drug regulatory agencies, which has also prompted more researchers to focus on the potential treatment strategies of SCI. Therefore, the purpose of this review is to summarize and elaborate the research progress as well as the challenges and future of nanopharmaceuticals in the treatment of SCI, aiming to promote further research of nanopharmaceuticals in SCI.

Is Acceleration a Valid Proxy for Injury Risk in Minimal Damage Traffic Crashes? A Comparative Review of Volunteer, ADL and Real-World Studies

Injury claims associated with minimal damage rear impact traffic crashes are often defended using a "biomechanical approach," in which the occupant forces of the crash are compared to the forces of activities of daily living (ADLs), resulting in the conclusion that the risk of injury from the crash is the same as for ADLs. The purpose of the present investigation is to evaluate the scientific validity of the central operating premise of the biomechanical approach to injury causation; that occupant acceleration is a scientifically valid proxy for injury risk. Data were abstracted, pooled, and compared from three categories of published literature: (1) volunteer rear impact crash testing studies, (2) ADL studies, and (3) observational studies of real-world rear impacts. We compared the occupant accelerations of minimal or no damage (i.e., 3 to 11 kph speed change or "delta V") rear impact crash tests to the accelerations described in 6 of the most commonly reported ADLs in the reviewed studies. As a final step, the injury risk observed in real world crashes was compared to the results of the pooled crash test and ADL analyses, controlling for delta V. The results of the analyses indicated that average peak linear and angular acceleration forces observed at the head during rear impact crash tests were typically at least several times greater than average forces observed during ADLs. In contrast, the injury risk of real-world minimal damage rear impact crashes was estimated to be at least 2000 times greater than for any ADL. The results of our analysis indicate that the principle underlying the biomechanical injury causation approach, that occupant acceleration is a proxy for injury risk, is scientifically invalid. The biomechanical approach to injury causation in minimal damage crashes invariably results in the vast underestimation of the actual risk of such crashes, and should be discontinued as it is a scientifically invalid practice.