How much does the injury risk between average female and average male anthropometry differ? - A simulation study with open source tools for virtual crash safety assessments.

Differences in injury risk between females and males are often reported in field data analysis. The aim of this study was to investigate the differences in kinematics and injury risks between average female and male anthropometry in two exemplary use cases. A simulation study comprising the newly introduced VIVA+ human body models (HBM) was performed for two use cases. The first use case relates to whiplash associated disorders sustained in rear impacts and the second to femur fractures in pedestrians impacted by passenger cars as field data indicates that females have higher injury risk compared to males in these scenarios. Detailed seat models and a generic vehicle exterior were used to simulate crash scenarios close to those currently tested in consumer information tests. In the evaluations with one of the vehicle seats and one car shape the injury risks were equal for both models. However, the risk of the average female HBM for whiplash associated disorders was 1.5 times higher compared to the average male HBM for the rear impacts in the other seat and 10 times higher for proximal femur fractures in the pedestrian impacts for one of the two evaluated vehicle shapes.. Further work is needed to fully understand trends observed in the field and to derive appropriate countermeasures, which can be performed with the open source tools introduced in the current study.

Prevalence of whiplash injury and its association with quality of life in local residents in Japan: A cross sectional study.

BACKGROUND: Associations between whiplash injuries and quality of life (QOL) have been previously published by conducting surveys among patients. This study aimed to investigate the prevalence of whiplash injuries in a Japanese community, and the association between whiplash injuries and QOL was also determined. METHODS: In all, 1140 volunteers participated in this study, filled out a questionnaire about whether they had experienced a whiplash injury, or had any neck pain or neck-shoulder stiffness in the previous 3 months, and completed the Medical Outcomes Study 36-Item Short-Form Health Survey. QOL was evaluated from the eight domain scores, and the Physical Component Summary (PCS) and Mental Component Summary (MCS) scores. We compared the characteristics, habits, history, medication, body mass index, and health-related QOL (eight domains, PCS and MCS scores) between the groups with whiplash injuries and no whiplash injuries for each sex. Multiple linear regressions with the forced-entry procedure were performed to evaluate the effects of a whiplash injury on the PCS and MCS. A p-value of <0.05 was considered statistically significant. RESULTS: The prevalence of whiplash injuries was 7.7% and 9.6% in men and women, respectively. The percentage of those who experienced whiplash injuries with symptoms persisting for more than 3 months was 34.3% and 24.2% in men and women, respectively. The prevalence of neck symptoms was significantly higher in the whiplash injury group than in the non-whiplash injury group. Multiple linear regression analysis showed that, although whiplash injuries were associated with poor health-related QOL in men, age was more associated with health-related QOL than whiplash injuries in both sexes. CONCLUSION: The prevalence of whiplash injuries was 7.7% and 9.6% in men and women in local residents in Japan, respectively. Whiplash injuries were poorly associated with a poor health-related QOL in men (P = 0.015).

Risk factors for developing chronic whiplash disorders.

BACKGROUND: Whiplash injury is one of the most common injuries in traffic accidents. Most of the injured recover within three months, however, a significant number have symptoms much longer. OBJECTIVE: The aim of this study was to determine the basic epidemiological characteristics of whiplash (gender, age, collision type, the type of participants in an accident, clinical signs) on Bosnia and Herzegovina roads and identify risk factors for chronic symptoms. METHODS: The subjects of this retrospective study were traffic accident whiplash patients who were diagnosed, treated and monitored in a single hospital center. The initial examination was performed on the day or the day after the accident and follow-up examinations after four weeks, three months, and six months. RESULTS: Out of the 241 patients in this study, 14.1% had symptoms over six months after the trauma. 54.7% of the injured belong to the third and fourth decade and close to 80% were younger than 50 years. In addition to neck pain, the most common symptoms were limited neck mobility (69.7%), muscle spasms (63.5%), palpable pain of neck muscles (56%), headache (43.6%), nausea (23.7%). Statistical analysis showed a positive impact of age, Quebec Task Force (QTF) grade II, and more injury severity and cervical spine degenerative changes on prolonged recovery. CONCLUSIONS: The overwhelming majority of the injured belong to the working population. QTF2+ score is a useful indicator for prolonged recovery and chronic symptoms. Age, QTF score and degenerative changes of the cervical spine indicate an increased risk for poor recovery and chronic symptoms.

Are Measures of Physical Function of the Neck Region Associated With Poor Prognosis Following a Whiplash Trauma?: A Systematic Review.

OBJECTIVE: The objective of this study was to synthesize the current evidence regarding the predictive ability of measures of physical function (PF) of the neck region and perceived PF on prognosis following a whiplash injury. MATERIALS AND METHODS: Electronic databases were searched by 2 independent reviewers up to July 2020, including MEDLINE, EMBASE, CINAHL, PsycINFO, Scopus, and Web of Science as well as gray literature. Eligible studies were selected by 2 reviewers who then extracted and assessed the quality of evidence. Observational cohort studies were included if they involved participants with acute whiplash-associated disorders (WAD), followed for at least 3 months postinjury, and included objective measures of neck PF or self-reported measures of PF as prognostic factors. Data could not be pooled and therefore were synthesized qualitatively. RESULTS: Fourteen studies (13 cohorts) were included in this review. Low to very low quality of evidence indicated that initial higher pain-related disability and higher WAD grade were associated with poor outcome, while there was inconclusive evidence that neck range of motion, joint position error, activity of the superficial neck muscles, muscle strength/endurance, and perceived functional capacity are not predictive of outcome. The predictive ability of more contemporary measures of neck PF such as the smoothness of neck movement, variability of neck motion, and coactivation of neck muscles have not been assessed. DISCUSSION: Although initial higher pain-related disability and higher WAD grade are associated with poor outcome, there is little evidence available investigating the role of neck PF on prognosis following a whiplash injury.

The Long-term Impact of Whiplash Injuries on Patient Symptoms and the Associated Degenerative Changes Detected Using MRI: A Prospective 20-year Follow-up Study Comparing Patients with Whiplash-associated Disorders with Asymptomatic Subjects.

STUDY DESIGN: A longitudinal, 20-year comparative study of patients with whiplash-associated disorders (WAD). OBJECTIVE: The aim of this study was to clarify the long-term impact of WAD on patient symptoms and on magnetic resonance imaging (MRI) findings of the cervical spine, in comparison with asymptomatic volunteers. SUMMARY OF BACKGROUND DATA: The long-term impact of WAD has not been fully elucidated. METHODS: Between 1993 and 1996, we conducted a cross-sectional comparative study of 508 acute WAD patients and 497 asymptomatic volunteers, all of whom underwent MRI on cervical spine and physical examinations. For this 20-year follow-up comparative study, 75 WAD patients and 181 control subjects aged <60 years were recruited from the original cohort. The MRI findings, including discs' signal intensities, posterior disc protrusions, anterior dural compressions, spinal cord disc space narrowing, and foraminal stenoses, were evaluated using two to four numerical grades. The results of the WAD patients and control subjects were compared. RESULTS: In this follow-up, the prevalence of shoulder stiffness (72.0% vs. 45.9%), headache (24.0% vs. 12.2%), and arm pain (13.3% vs. 3.9%) were significantly greater in WAD patients than in control subjects. The multiregression analysis revealed that a history of WAD was associated with shoulder stiffness (odds ratio [OR]: 3.36), headache (OR: 2.39), and arm pain (OR: 3.82). Although MRI findings in WAD patients were more degenerated than in control subjects in the initial study, all MRI findings were similar at the 20-year follow-up. There were no significant correlations between clinical cervical symptoms and progression in each MR finding in either group. CONCLUSION: After 20 years, whiplash injuries significantly impacted the residual symptoms of shoulder stiffness, headache, and arm pain when compared with initially asymptomatic volunteers. The progression of degenerative changes in the cervical intervertebral discs after 20 years revealed no association with existing whiplash injuries, neither did the residual cervical-related symptoms.Level of Evidence: 3.

Revisiting Risk-stratified Whiplash-exposed Patients 12 to 14 Years After Injury.

OBJECTIVE: The objective of this study was to evaluate the long-term predictive value of the Danish Whiplash Group Risk Assessment Score (DWGRAS) with 7 risk strata. DESIGN: E-questionnaire-based follow-up study (n=927) combining 2 cohorts of whiplash-injured patients, 1 observational (n=187) and 1 interventional randomized controlled trial (n=740). METHODS: Nine hundred twenty-seven previously healthy persons exposed to acute whiplash injury during motor vehicle collision were sent letter by postal service asking the addressee if they would respond to an E-questionnaire. Outcome measures were: whiplash-related disability, pain, use of medication/nonmedical treatment, work capacity. RESULTS: The response rate was 37%. Fifty-five percent reported whiplash-related disability. Fourteen percent reported daily symptoms. A strong relationship was found between risk strata and impact of event and between risk strata and disabling symptoms. CONCLUSIONS: Internal and long-term validation of DWGRAS was performed, but a low response rate indicates that results should be interpreted with caution. Furthermore, external validation needs to be done in long-term studies. An receiver operating characteristics curve of 0.73 (95% confidence interval 0.67; 0.79) predicting daily or weekly whiplash-related disability after 12 to 14 years was found using the DWGRAS risk score.

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

BACKGROUND: Cervical spine injury is a common result of traffic crashes, and such injuries range in severity from minor (i.e. sprain/strain) to moderate (intervertebral disk derangement) to serious and greater (fractures, dislocations, and spinal cord injuries). There are currently no reliable estimates of the number of crash-related spine injuries occurring in the US annually, although several publications have used national crash injury samples as a basis for estimating the frequency of both cervical and lumbar spinal disk injuries occurring in lower speed rear impact crashes. PURPOSE: To develop a reliable estimate of the number of various types of cervical spine injuries occurring in the US by comparing data from national crash injury to national hospital ED and inpatient samples. STUDY DESIGN: Comparative cross-sectional METHODS: Cervical spine injury data were accessed, analyzed, and compared from 3 national databases; the National Automotive Sampling System-Crashworthiness Data System (NASS-CDS), Nationwide Emergency Department Sample (NEDS), and the Nationwide Inpatient Sample (NIS). RESULTS: It is estimated that there are approximately 869,000 traffic crash-related cervical spine injuries seen in hospitals in the US annually, including around 841,000 sprain/strain (whiplash) injuries, 2800 spinal disk injuries, 23,500 fractures, 2800 spinal cord injuries, and 1500 dislocations. Because of a highly restrictive inclusion criteria for both crash and injury types, as well as a very small sample size, the NASS-CDS underestimated all types of crash-related cervical spine injuries seen in US hospital emergency departments by 84 %. The injury type with the largest degree of underestimation in the NASS-CDS was cervical disk injuries, which were estimated at an 88 % lower frequency than in the NEDS. National insurance claim data, which include cases of cervical disk injury diagnosed both in and outside of the ED, indicate that the NEDS likely undercounts cervical disk injuries by 92 %, and thus the NASS-CDS correspondingly undercounts such injuries by 99 % or more. CONCLUSIONS: Because of a limited sample size and restrictive criteria for both crash and injury inclusion, the NASS-CDS cannot be used to estimate the number of crash-related spinal injuries of any type or severity in the US. The most inappropriate use of the database is for estimating the number of spinal injuries resulting from low speed rear impact collisions, as the NASS-CDS samples fewer than 1 in 100,000 of the cervical spine injuries of any type occurring in low speed rear impact collisions.

Associations between the injustice experience questionnaire and treatment term in patients with acute Whiplash-associated disorder in Japan: Comparison with Canadian data.

INTRODUCTION: This study aimed to investigate the differences in the Injustice Experience Questionnaire (IEQ) scores during the early period after the diagnosis of Whiplash-associated disorder (WAD) between Japanese and Canadian samples, and the associations between the IEQ scores and treatment terms in Japanese patients with acute WAD. METHODS: We used secondary data for the IEQ scores of Canadian patients with acute WAD. In Japan, we collected data from 85 consecutively enrolled patients with acute WAD, and their treatment terms were collected; these referred to the number of days between the date of injury and the closure date of the insurance claim and the number of treatment visits. Before treatment, the Numeric Rating Scale, Neck Disability Index, Hospital Anxiety and Depression Scale, IEQ, and Euro Quality of Life five-dimensional questionnaire were administered. The variables were subjected to multivariate analysis with each treatment term. RESULTS: The IEQ scores were higher in Japan than in Canada. Through multiple regression analysis, IEQ scores were independently correlated with treatment terms. The optimal cutoff point of the IEQ scores for a prolonged treatment term was 21 and 22 points, respectively. CONCLUSIONS: The IEQ scores were associated with treatment terms in patients with acute WAD in Japan.

There's Nothing Broken. You've Had a Whiplash, That's It: A Qualitative Study of Comorbid Posttraumatic Stress Disorder and Whiplash Associated Disorders.

BACKGROUND: Posttraumatic stress disorder (PTSD) symptoms are common in chronic Whiplash associated disorders (WAD) and have been found to be associated with higher levels of pain and disability. Theoretical frameworks have suggested that PTSD and pain not only coexist, but also mutually maintain one another. Although the comorbidity has been subject to increasing quantitative research, patients' experiences of the comorbidity and symptom interaction remain largely uninvestigated using qualitative methods. OBJECTIVE: The present study set out to explore the potential relationship of PTSD and pain in people with WAD and properly assessed PTSD after motor vehicle accidents. METHODS: A qualitative explorative study of eight individual face-to-face semistructured interviews were conducted. Interviews were recorded and transcribed verbatim and analyzed using framework analysis. RESULTS: Through the analysis, we developed three overarching themes. The first theme illustrated the complex and burdensome comorbidity with overlapping and transdiagnostic symptoms, whereas the second theme highlighted how several circumstances, some related to the health care system, could extend and amplify the traumatic response. The final theme illustrated symptom associations and interactions, particularly between pain and PTSD, both supporting and rejecting parts of the mutual maintenance framework. CONCLUSIONS: These findings underlined the great complexity and variability of the comorbidity and the traumatic event, but also emphasized how experiences of psyche and soma seem closely connected in these patients. The results provide support for the importance of thorough assessment by multidisciplinary teams, minimizing distress post-injury, and a critical approach to the idea of mutual maintenance between pain and PTSD.

A comparison of anti-whiplash seats during low/moderate speed rear-end collisions.

Objectives: The Insurance Institute for Highway Safety (IIHS) rates automotive seats as good, acceptable, marginal, and poor on their abilities to prevent whiplash injuries during rear-end collisions. The goal of this study was to compare the performance of some good- and poor-rated seats at speed changes below 16 km/h where some whiplash injuries occur.Methods: A BioRID II anthropometric test device (ATD) underwent rear-end collisions from 2 to 14 km/h while seated on one of two Volvo Whiplash Prevention seats (WHIPS), a Saab Active Head Restraint seat (SAHR), or a General Motors High Retention seat (GMHR). The WHIPS and SAHR seats were rated good whereas the GMHR seat was rated poor by the IIHS. The ATD's kinematics, kinetics and three neck injury criteria were evaluated across the range of collision severities.Results: Most of the head and torso kinematics, kinetics and injury criteria exhibited graded responses with increasing collision severities. Only head extension angle remained relatively similar across all speed changes. Differences between the good- and poor-rated seats were most apparent in the upper neck loads and moments, and head retraction for speed changes greater than 6 km/h.Conclusions: The relatively similar occupant responses across all seats could explain the marginal reductions in whiplash injury risk between good- and poor-rated seats in field studies. Further research into the design of anti-whiplash devices is required to better understand the link between occupant response and injury, and to better mitigate the risk of whiplash injuries during rear-end collisions.

Neck pain and headache after whiplash injury: a systematic review and meta-analysis.

Neck pain and headache are 2 of the most common complications of whiplash injury. Therefore, we performed a systematic literature search on PubMed and Embase for publications reporting on the prevalence of neck pain and headache after whiplash injury. The literature search identified 2709 citations of which 44 contained relevant original data. Of these, 27 studies provided data for the quantitative analysis. For non-population-based studies, the present meta-analysis showed that a pooled relative frequency of neck pain was 84% confidence interval (68%-95%) and a pooled relative frequency of headache was 60% (46%-73%), within 7 days after whiplash injury. At 12 months after injury, 38% (32%-45%) of patients with whiplash still experienced neck pain, while 38% (18%-60%) of whiplash patients reported headache at the same time interval after injury. However, we also found considerable heterogeneity among studies with I-values ranging from 89% to 98% for the aforementioned meta-analyses. We believe that the considerable heterogeneity among studies underscores the need for clear-cut definitions of whiplash injury and standardized reporting guidelines for postwhiplash sequelae such as neck pain and headache. Future studies should seek to optimize these aspects paving the way for a better understanding of the clinical characteristics and natural course of whiplash-associated sequelae.

The Course of Orofacial Pain and Jaw Disability After Whiplash Trauma: A 2-year Prospective Study.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: The aim of this study was to evaluate the course of orofacial pain and jaw disability in relation to neck pain, neck disability, and psychosocial factors at the acute stage and the chronic stage after whiplash trauma. SUMMARY OF BACKGROUND DATA: Many individuals report chronic pain in the orofacial region after whiplash trauma. The possible association between whiplash trauma and orofacial pain is debated. Prospective studies are therefore needed to evaluate the development of orofacial pain after whiplash trauma. METHODS: Within 1 month following a whiplash trauma, 176 cases were examined and compared to 116 controls with questionnaires concerning neck and jaw pain and related disability, nonspecific physical symptoms and depression. At the 2-year follow-up, 119 cases (68%) and 104 controls (90%) were re-examined. RESULTS: Compared to controls, cases reported more jaw and neck pain, both at baseline and follow-up. A majority (68%) of cases with pain in the jaw region in the acute stage also reported jaw pain at the follow-up. The intensity of jaw and neck pain was correlated both at baseline and follow-up. Both neck pain and jaw pain were correlated to nonspecific physical symptoms and to depression. CONCLUSION: Orofacial pain and jaw disability related to neck pain are often present already at the acute stage after whiplash trauma and persist into the chronic stage for most individuals. Assessment following whiplash trauma should therefore include both the neck and the orofacial regions. More studies are needed to further evaluate risk factors for development of orofacial pain after whiplash trauma. LEVEL OF EVIDENCE: 3.

An analysis of whiplash injury outcomes in an Irish population: a retrospective fifteen-year study of a spine surgeon's experience.

BACKGROUND: Whiplash injuries result from an acceleration-deceleration injury of the cervical spine. The associated symptoms may include neck pain/stiffness; cervicogenic headaches; interscapular pain; upper limb pain, paraesthesia and weakness. Current treatment protocols recommend conservative management of low-grade whiplash. AIMS: To assess changing practices over time in the management of whiplash-associated disorders in the practice of a specialist spine surgeon and to explore the impact of associated litigation on this patient cohort. METHODS AND RESULTS: The private medical records of a specialist spine surgeon over a 15-year period (1996-2011) were reviewed. Three hundred one consecutive patients were identified: 169 females and 132 males with a mean age of 37 years ± 13. All were referred by primary care with potential soft tissue injury of the cervical spine following a road traffic accident. Fifty-eight percent had associated back pain. An initial conservative approach was adopted in all cases. Subsequently, 4 patients underwent surgical intervention. Ninety-three percent reported chronic neck pain > 6 months after their injury. Age was the only significant predictor of chronic neck pain (adjusted OR 1.29 for every 5-year increase, p = 0.03). All were ultimately involved in litigation. The establishment of the Personal Injuries Board did not influence the litigation duration during the study period. CONCLUSION: Whiplash poses a significant societal economic burden in Ireland and was associated with prolonged symptoms including neck pain and upper limb neuropathic symptoms in this cohort. Associated low-back pain was common. Litigation was linked with presentation in all cases.

Factors influencing outcomes among patients with whiplash-associated disorder: A population-based study in Japan.

INTRODUCTION: Only a few, large population-based studies, have reported on whiplash-associated disorder (WAD). However, none of them have investigated the influence of crash severity on WAD outcome. In the present study, we aimed to determine whether crash severity predicts outcomes among patients with no-fault government insurance for acute WAD. METHODS: We utilized data from a compulsory, no-fault government automobile liability insurance agency in Japan. Individuals involved in a car accident between April 2001 and June 2015 with residual disabilities reported at the end of the treatment between October 2014 and September 2015 were included. Crash severity was assessed based on property damage costs, size of the other vehicle (large car, medium car, small car, or two-wheeled vehicles), and collision types (rear-end collision, contact with vehicle moving in the same direction, or in the opposite direction). Outcomes included the time to claim closure and the number of treatment visits. RESULTS: We analyzed data for a total of 52,251 individuals (28,571 male and 23,680 female) with a median age of 44 years (range: 2-95 years). The median time to claim closure was 220 days (range: 1-4,938 days), and the median number of treatment visits was 102 (range: 1-2,492). There was no significant association between outcomes and property damage costs or size of the other vehicle. Collision types exhibited no consistent association with outcomes. However, older age and affected body parts, in addition to the neck, were independent risk factors for delayed claim closure and a large number of visits, although, all odds ratios were low (often less than 2.0). CONCLUSIONS: There was no obvious association of outcomes with property damage costs, size of the other vehicle, or collision types in acute WAD patients. Further studies should investigate the influence of psychological factors, compensation systems, and cultural conditions.

Risk of traffic accidents after onset of vestibular disease assessed with a surrogate marker.

OBJECTIVES: To determine if the risk of traffic accidents increases after disease onset in patients with acute vestibular disorders. That could provide a valid rationale for guidelines on driving restrictions. METHODS: 5,260,054 patient data (> 18 years of age) from a statutory health insurer were used to identify traffic injuries in incident cases of Menière's disease (MD) and vestibular neuritis (VN) in 2010-2013. Incident diagnoses were defined as the absence of such diagnoses in the preceding 5 years. Comparators were insured individuals with no such diagnoses throughout 2005-2017. The surrogate for traffic injuries were whiplash injuries coded in ICD-10 as diagnosis of sprain of ligaments of the cervical spine without structural changes. RESULTS: We identified 4509 incident patients with Menière's disease and 25,448 with vestibular neuritis and 5,102,655 controls with no such diagnoses throughout the observation period. The incidence of traffic injuries was increased for both vestibular disorders prior to the time point of diagnosis-MD 0.72 [0.47; 0.97] and VN 0.66 [0.56; 0.76] compared to controls (0.46 [0.46; 0.47]). The temporal course of incidence in whiplash injuries showed no increase and was 0.64 [0.41; 0.88] for MD at diagnosis and 0.73 [0.48; 0.98] after diagnosis, for VN it was 0.81 [0.70; 0.92] at diagnosis and 0.65 [0.55; 0.74] after diagnosis. CONCLUSIONS: Although these data were not originally collected to address the research question, they provide a valid body of evidence. There is no rationale for driving restrictions, which substantially interfere with the individuals' quality of life, in patients with incident MD and VN.

Influence of morphological variations on cervical spine segmental responses from inertial loading.

OBJECTIVES: The objective of this study was to investigate the influence of morphological variations in osteoligamentous lower cervical spinal segment responses under postero-anterior inertial loading. METHODS: A parametric finite element model of the C5-C6 spinal segment was used to generate models. Variations in the vertebral body and facet depth (anteroposterior), posterior process length, intervertebral disc height, facet articular process height and slope, segment orientation ranging from lordotic to straight, and segment size were parameterized. These variations included male-female differences. A Latin hypercube sampling method was used to select parameter values for model generation. Forces and moments associated with the inertial loading were applied to the generated model segments. The 7 parameters were grouped as local or global depending on the number of spinal components involved in the shape variation. Four output responses representing overall segmental and soft tissue responses were analyzed for each model variation: response angle of the segment, anterior longitudinal ligament stretch, anterior capsular ligament stretch, and facet joint compression in the posterior region. Pearson's correlation coefficient was used to compute the correlations of these output responses with morphological variations. RESULTS: Fifty models were generated from the parameterized model using a Latin hypercube sampling technique. Variation in response angle among the models was 4° and was most influenced by change in the combined dimension of vertebral body and facet depth, followed by size of the segment. The maximum anterior longitudinal ligament stretch varied between 0.1 and 0.3 and was strongly influenced by the change in the segment orientation. The anterior facet joint region sustained tension, whereas the posterior region sustained compression. For the anterior capsular ligament stretch, the most influential global variation was segment orientation, whereas the most influential local variations were the facet height and facet angle parameters. In the case of posterior facet joint compression, segment orientation was again most influential, whereas among the local variations, the facet angle had the most influence. CONCLUSION: Shape variations in the intervertebral disc influenced segmental rotation and ligament responses; however, the influence of shape variations in the facet joint was confined to capsular ligament responses. Response angle was most influenced by the vertebral body depth variations, explaining greater segmental rotations in female spines. Straighter spine segments sustained greater posterior facet joint compression, which may offer an explanation for the higher incidence of whiplash-associated disorders among females, who exhibit a straighter cervical spine. The anterior longitudinal ligament stretch was also greater in straighter segments. These findings indicate that the morphological features specific to the anatomy of the female cervical spine may predispose it to injury under inertial loading.

Thoracic dysfunction in whiplash associated disorders: A systematic review.

BACKGROUND: Research investigating Whiplash Associated Disorder (WAD) has largely focused on the cervical spine yet symptoms can be widespread. Thoracic spine pain prevalence is reported ~66%; perhaps unsurprising given the forceful stretch/eccentric loading of posterior structures of the spine, and the thoracic spine's contribution to neck mobility/function. Approximately 50% WAD patients develop chronic pain and disability resulting in high levels of societal and healthcare costs. It is time to look beyond the cervical spine to fully understand anatomical dysfunction in WAD and provide new directions for clinical practice and research. PURPOSE: To evaluate the scope and nature of dysfunction in the thoracic region in patients with WAD. METHODS: A systematic review and data synthesis was conducted according to a pre-defined, registered (PROSPERO, CRD42015026983) and published protocol. All forms of observational study were included. A sensitive topic-based search strategy was designed from inception to 1/06/16. Databases, grey literature and registers were searched using a study population terms and key words derived from scoping search. Two reviewers independently searched information sources, assessed studies for inclusion, extracted data and assessed risk of bias. A third reviewer checked for consistency and clarity. Extracted data included summary data: sample size and characteristics, outcomes, and timescales to reflect disorder state. Risk of bias was assessed using the Newcastle-Ottawa Scale. Data were tabulated to allow enabling a semi-qualitative comparison and grouped by outcome across studies. Strength of the overall body of evidence was assessed using a modified GRADE. RESULTS: Thirty eight studies (n>50,000) which were conducted across a range of countries were included. Few authors responded to requests for further data (5 of 9 contacted). Results were reported in the context of overall quality and were presented for measures of pain or dysfunction and presented, where possible, according to WAD severity and time point post injury. Key findings include: 1) high prevalence of thoracic pain (>60%); higher for those with more severe presentations and in the acute stage, 2) low prevalence of chest pain (<22%), 3) evidence of thoracic outlet syndrome, with some association to and involvement of the brachial plexus, 4) muscle dysfunction in the form of heightened activity of the sternocleidomastoid or delayed onset of action of the serratus anterior, 5) high prevalence of myofascial pain and trigger points in the scalene muscles, sternocleidomastoid and mid/lower fibres of trapezius muscle (48-65%), and 6) inconclusive evidence of altered thoracic posture or mobility. CONCLUSIONS: Considerable evidence supports thoracic pain and dysfunction in patients with WAD, involving primarily nerves and muscles. Notwithstanding the low/very low level of evidence from this review, our findings do support a more extensive clinical evaluation of patients presenting with WAD. Additional high quality research is required to further characterise dysfunction across other structures in the thoracic region, including but not limited to the thoracic spine (mobility and posture) and thoracic muscles (stiffness, activation patterns). In turn this may inform the design of clinical trials targeting such dysfunction.

A Comprehensive Review of Low-Speed Rear Impact Volunteer Studies and a Comparison to Real-World Outcomes.

STUDY DESIGN: This study combined all prior research involving human volunteers in low-speed rear-end impacts and performed a comparative analysis of real-world crashes using the National Automotive Sampling System - Crashworthiness Data System. OBJECTIVE: The aim of this study was to assess the rates of neck pain between volunteer and real-world collisions as well as the likelihood of an injury beyond symptoms as a function of impact severity and occupant characteristics in real-world collisions. SUMMARY OF BACKGROUND DATA: A total of 51 human volunteer studies were identified that produced a dataset of 1984 volunteer impacts along with a separate dataset of 515,601 weighted occupants in real-world rear impacts. METHODS: Operating-characteristic curves were created to assess the utility of the volunteer dataset in making predictions regarding the overall population. Change in speed or delta-V was used to model the likelihood of reporting symptoms in both real-world and volunteer exposures and more severe injuries using real-world data. Logistic regression models were created for the volunteer data and survey techniques were used to analyze the weighted sampling scheme with the National Automotive Sampling System database. RESULTS: Symptom reporting rates were not different between males and females and were nearly identical between laboratory and real-world exposures. The minimal risk of injury predicted by real-world exposure is consistent with the statistical power of the large number of volunteer studies without any injury beyond the reporting of neck pain. CONCLUSION: This study shows that volunteer studies do not under-report symptoms and are sufficient in number to conclude that the risk of injury beyond neck strain under similar conditions is essentially zero. The real-world injury analyses demonstrate that rear impacts do not produce meaningful risks of cervical injury at impacts of similar and greater severity to those of the volunteer research. Future work concerning the mechanism of whiplash-related trauma should focus on impacts of severity greater than those in the current literature. LEVEL OF EVIDENCE: 3.

A predictive model to analyze factors affecting the presence of mild whiplash-associated disorders in minor motor vehicle crashes based on the Korean In-Depth Accidents Study (KIDAS) Database.

OBJECTIVES: We aimed to analyze factors affecting the severity of mild whiplash-associated disorders (WADs) and to develop a predictive model to evaluate the presence of mild WAD in minor motor vehicle crashes (MVCs). METHODS: We used the Korean In-Depth Accident Study (KIDAS) database, which collects data from 4 regional emergency centers, to obtain data from 2011 to 2017. The Collision Deformation Classification code was obtained as vehicle's damage information, and Abbreviated Injury Scale (AIS), Maximum Abbreviated Injury Scale (MAIS), and Injury Severity Score (ISS) were used as occupant's injury information. The degree of WAD was determined using the Quebec Task Force (QTF) classification, comprised of 5 stages (QTF 0-4), depending on the occupant's pain and the physician's findings. QTF 1 was defined as mild WAD, and we used QTF 0 to define those who were uninjured. For KIDAS data between 2011 and 2016, a logistic regression model was used to identify factors affecting the occurrence of mild WAD and a predictive model was constructed. Internal validity was estimated using random bootstrapping, and external validity was evaluated by applying 2017 KIDAS data. Of the 2,629 occupants in the KIDAS database from 2011 to 2016, after applying several exclusion conditions, 459 occupants were used to develop the predictive model. The external validity of the derived predictive model was assessed using the 13 MVC occupants from the 2017 KIDAS database meeting our inclusion criteria. Among the 137 MVC occupants from the 2017 KIDAS database for analysis of the external validity of the derived predictive model, the predictive model was verified for 13 MVC occupants. RESULTS: Logistic regression analysis was used to derive a predictive model based on sex, age, body mass index, type of vehicle, belt status, seating row, crush type, and crush extent. This predictive model had an explanatory power of 65.5% to determine an actual QTF of 0 and 1 (c-statistics: 0.655). As a result of the external validity analysis of the predictive model using data from the 2017 KIDAS database (N = 13), sensitivity, specificity, and accuracy were 0.500, 0.857, and 0.692, respectively. CONCLUSIONS: Using the predictive model, the results of the external validity analysis showed low sensitivity but high specificity. This predictive model provided meaningful results, with a high success rate for determining no injury to an occupant. Given our study results, future research is needed to create a more accurate predictive model that includes relevant technical and sociological factors.