Novel insights into the interplay between ventral neck muscles in individuals with whiplash-associated disorders

Neck muscle function improves after neck exercises in individuals with whiplash-associated disorders: a case-control ultrasound study with speckle-tracking analyses

A whiplash injury can alter neck muscle function, which remains years after the injury and may explain why symptoms such as persistent pain and disability occur. There is currently limited knowledge about dynamic neck muscle function in chronic whiplash-associated disorders (WAD), and about the extent to which altered muscle function can improve after rehabilitation. Ultrasound can detect mechanical neck muscle function by measuring real-time deformation and deformation rate in the muscles. This method was used for five dorsal neck muscles in participants with chronic WAD versus matched controls in resistant neck rotation. We obtained real-time, non-invasive ultrasound measurements using speckle tracking, multivariate analyses, and mixed-design ANOVA analyses. The results showed altered deformation in the three deepest neck muscle layers, with less deformation area in the WAD group compared to controls in rotation to the most painful side at baseline. Participants in the WAD group performed three months of neck-specific exercises, resulting in improved deformation in the deep neck muscles in WAD and with a similar deformation pattern to controls, and the significant group differences ceased. We reveal new and important insights into the capability of ultrasound to diagnose altered neck muscle function and evaluate an exercise intervention.

Effect of neck-specific exercises with and without internet support on cervical range of motion and neck muscle endurance in chronic whiplash-associated disorders: analysis of functional outcomes of a randomized controlled trial

OBJECTIVE

To compare the effects of a neck-specific exercise programme with internet support and 4 physiotherapist sessions (NSEIT) and the same neck-specific exercises supervised by a physiotherapist (NSE) on neck muscle endurance and cervical range of motion.

DESIGN

Randomized controlled trial.

PATIENTS

A total of 140 participants with chronic whiplash-associated disorders grade II or grade III were randomly assigned to the NSEIT or NSE groups.

METHODS

Outcomes were changes in active cervical range of motion, cranio-cervical flexion test, neck muscle endurance, and neck pain, at 3- and 15-month follow-ups.

RESULTS

There were no significant differences between the NSEIT and NSE groups. There was a significant group-by-time inter-action effect in active cervical range of motion flexion/extension where the NSEIT group improved to 3-month follow-up, but the NSE group did not. Both groups were significantly improved over time in all other outcomes (p < 0.001) at 3- and 15-month follow-ups, with effect size between 0.64 and 1.35 in active cervical range of motion, cranio-cervical flexion test, dorsal neck muscle endurance, and neck pain, and effect size between 0.22 and 0.42 in ventral neck muscle endurance.

CONCLUSION

Both NSE and NSEIT led to improved neck function. Depending on the patients' needs, either NSE or NSEIT could be used as treatment for patients with chronic whiplash-associated disorders.

The effect of a neck-specific exercise program on cervical kinesthesia for patients with chronic whiplash-associated disorders: a case-control study

INTRODUCTION

Cervical kinesthesia is an important part of movement control and of great importance for daily function. Previous research on kinesthesia in whiplash-associated disorders (WAD) has focused on grades I-II. More research is needed on WAD grade III. The aim of this study was to investigate cervical kinesthesia in individuals with WAD grades II-III before and after a neck-specific exercise intervention and compare them to healthy controls.

METHODS

A prospective, case-control study with a treatment arm (n = 30) and a healthy control arm (n = 30) was conducted in Sweden. The WAD group received a neck-specific exercise program for 12 weeks. The primary outcome to evaluate kinesthesia was neck movement control (the Fly test). Secondary outcomes were neck disability, dizziness and neck pain intensity before and after the Fly test. Outcomes were measured at baseline and post-treatment. The control arm underwent measurements at baseline except for the dizziness questionnaire. A linear mixed model was used to evaluate difference between groups (WAD and control) and over time, with difficulty level in the Fly test and gender as factors.

RESULTS

Between-group analysis showed statistically significant differences in three out of five kinesthetic metrics (p = 0.002 to 0.008), but not for the WAD-group follow-up versus healthy control baseline measurements. Results showed significant improvements for the WAD-group over time for three out of five kinaesthesia metrics (p < 0.001 to 0.008) and for neck disability (p < 0.001) and pain (p = 0.005), but not for dizziness (p = 0.70).

CONCLUSIONS

The exercise program shows promising results in improving kinesthesia and reducing neck pain and disability in the chronic WAD phase. Future research might benefit from focusing on adding kinesthetic exercises to the exercise protocol and evaluating its beneficial effects on dizziness or further improvement in kinesthesia.

IMPACT STATEMENT

Kinesthesia can be improved in chronic WAD patients without the use of specific kinesthetic exercises.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT03664934), first registration approved 11/09/2018.

Efficacy of Neck-Specific Exercise With Internet Support Versus Neck-Specific Exercise at a Physiotherapy Clinic in Chronic Whiplash-Associated Disorders: Multicenter Randomized Controlled Noninferiority Trial

BACKGROUND

Neck-specific exercises (NSE) supervised by a physiotherapist twice a week for 12 weeks have shown good results in chronic whiplash-associated disorders (WADs), but the effect of exercise delivered via the internet is unknown.

OBJECTIVE

This study examined whether NSE with internet support (NSEIT) and 4 physiotherapy sessions for 12 weeks were noninferior to the same exercises supervised by a physiotherapist twice a week for 12 weeks (NSE).

METHODS

In this multicenter randomized controlled noninferiority trial with masked assessors, we recruited adults aged 18-63 years with chronic WAD grade II (ie, neck pain and clinical musculoskeletal signs) or III (ie, grade II plus neurological signs). Outcomes were measured at baseline and at 3- and 15-month follow-ups. The primary outcome was change in neck-related disability, measured with the Neck Disability Index (NDI; 0%-100%), with higher percentages indicating greater disability. Secondary outcomes were neck and arm pain intensity (Visual Analog Scale [VAS]), physical function (Whiplash Disability Questionnaire [WDQ] and Patient-Specific Functional Scale [PSFS]), health-related quality of life (EQ-5D-3L and EQ VAS), and self-rated recovery (Global Rating Scale [GRS]). The analyses were conducted on an intention-to-treat basis and with the per-protocol approach as sensitivity analyses.

RESULTS

Between April 6, 2017, and September 15, 2020, 140 participants were randomly assigned to the NSEIT group (n=70) or the NSE group (n=70); 63 (90%) and 64 (91%), respectively, were followed up at 3 months, and 56 (80%) and 58 (83%), respectively, at 15 months. NSEIT demonstrated noninferiority to NSE in the primary outcome NDI, as the 1-sided 95% CI of the mean difference in change did not cross the specified noninferiority margin (7 percentage units). There were no significant between-group differences in change in NDI at the 3- or 15-month follow-up, with a mean difference of 1.4 (95% CI -2.5 to 5.3) and 0.9 (95% CI -3.6 to 5.3), respectively. In both groups, the NDI significantly decreased over time (NSEIT: mean change -10.1, 95% CI -13.7 to -6.5, effect size=1.33; NSE: mean change -9.3, 95% CI -12.8 to -5.7, effect size=1.19 at 15 months; P<.001). NSEIT was noninferior to NSE for most of the secondary outcomes except for neck pain intensity and EQ VAS, but post hoc analyses showed no differences between the groups. Similar results were seen in the per-protocol population. No serious adverse events were reported.

CONCLUSIONS

NSEIT was noninferior to NSE in chronic WAD and required less physiotherapist time. NSEIT could be used as a treatment for patients with chronic WAD grades II and III.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03022812; https://clinicaltrials.gov/ct2/show/NCT03022812.

Neck-related function and its connection with disability in chronic whiplash-associated disorders: secondary analysis of a randomized controlled study

BACKGROUND

More than 40% of individuals with whiplash injury experience persistent neck pain and disability years later, called whiplash-associated disorders (WAD). A randomized controlled trial evaluated three exercise interventions in WAD and found that neck-specific exercise (NSE) and NSE with a behavioral approach (NSEB) significantly improve disability compared to prescribed physical activity (PPA). However, the relationship between neck-related function and disability is inconclusive and needs to be further investigated.

AIM

The present study compares the effect of NSE, NSEB, and PPA on neck muscle endurance (NME), active cervical range of motion (AROM), grip strength, and pain intensity immediately before and after the physical tests, and neck disability in individuals who are below or above the cut-off for normative reference values regarding NME, AROM, and grip strength.

DESIGN

Follow-up to a multicenter randomized clinical trial.

SETTING

Primary healthcare centers and hospital outpatient services.

POPULATION

The selected population of this study included 216 patients with persistent WAD grades II and III.

METHODS

This is a secondary analysis including 12 months' follow-up. NME, AROM, grip strength, pain, and self-reported disability were recorded at baseline, 3, 6, and 12 months. Linear mixed models were used, and sub-group analyses evaluated by non-parametric tests.

RESULTS

NSE and NSEB resulted in greater improvements compared to PPA (P<0.01) in ventral (only males) and dorsal NME, AROM, and pain intensity during testing. We found no significant between-group differences in grip strength and no significant differences between the NSE and NSEB groups. Improvement in disability was seen at the 12-month follow-up of NSE and/or NSEB for individuals both below and above the cut-off reference values for NME and AROM. Individuals in the PPA group below the reference values for NME and AROM reported increasing disability at 12 months compared to baseline.

CONCLUSIONS

The results suggest that neck-specific exercises (i.e., NSE, NSEB) improve clinical function and decrease disability in chronic WAD compared to PPA, but PPA can increase disability for patients with low neck-related function.

CLINICAL REHABILITATION IMPACT

Higher neck-related function seems to be important for reduced disability in persistent WAD grades II and III. Neck-specific exercises could lead to higher neck-related function.

The nosological classification of whiplash-associated disorder: a narrative review

Whiplash-associated disorder (WAD) is the most common complaint and purported cause of chronic disability associated with motor vehicle collisions in North America. However, its construct validity remains controversial. This narrative review of the literature summarises the evidence underlying the most commonly theorised biological and psychosocial mechanisms of WAD pathogenesis. While the face validity of WAD is good, empirical evidence supporting the various constructs suggesting a causal link between a trauma mechanism and the development of symptoms is poor. Because individual expectations of recovery are outcome-predictive, future research is necessary to develop a better understanding of how to enhance expectancies in order to help affected motorists gain a greater sense of control over their health and wellbeing.

Ultrasound Investigation of Dorsal Neck Muscle Deformation During a Neck Rotation Exercise

OBJECTIVES

Neck-specific exercise can reduce neck pain and increase function, but information on how different neck muscle layers are activated during neck exercises is scarce. The aim of this study was to investigate deformation and deformation rate in 5 dorsal neck muscles and the correlation among these muscles during a loaded dynamic exercise used in clinical practice.

METHODS

Deformation and deformation rate were investigated in 5 dorsal right-sided neck muscles in 20 individuals without neck pain using ultrasonography and speckle-tracking analyses. Repeated-measures analysis of variance was used to measure differences between the muscles, and correlations between neck muscles were analyzed with Kendall's tau.

RESULTS

Deformation in left (contralateral) rotation showed significant differences among the muscles (P = .01), with higher deformation of the semispinalis capitis muscle compared with the trapezius muscle (P = .02). There were no significant differences among the 5 neck muscles in right (unilateral) rotation (P = .46). There were significant differences in deformation rate among muscles in both right and left rotation (P < .01). The trapezius muscles have the lowest deformation rate in right rotation (P < .01). In left rotation, the trapezius and multifidus muscles showed lower deformation rates compared with most of the other muscles (P < .03). Almost all muscles were correlated in both deformation and deformation rate.

CONCLUSION

The quadruped standing loaded dynamic neck exercise seemed to activate all the investigated neck muscles, with a tendency for more activation of the semispinalis capitis.

Neck-specific exercise for radiating pain and neurological deficits in chronic whiplash, a 1-year follow-up of a randomised clinical trial

Up to 90% of people with neurological deficits following whiplash injury report chronic symptoms. A recent unique study of neck-specific exercise showed positive results (post-intervention at 12 weeks), regarding arm pain and neurological deficits in people with chronic whiplash associated disorders (WAD). This 1-year follow-up of that randomised controlled study with assessor blinding aimed to examine whether neck-specific exercise with (NSEB) or without (NSE) a behavioural approach has long-term benefits over physical activity prescription (PPA) regarding arm pain and neurological deficits (n = 171). Interventions were: NSE, NSEB, or PPA. Follow-up of arm pain, paraesthesia bothersomeness (questionnaires) and clinical neurological tests were performed after 3, 6 and 12 months and analysed with Linear Mixed Models and General Estimating Equations. The NSE and/or NSEB groups reported significantly less pain and paraesthesia bothersomeness as well as higher odds of normal key muscle arm strength and of normal upper limb neural tension over the year (all p < 0.03), compared with PPA. In conclusion, results suggest that neck-specific exercise with or without a behavioural approach may have persisting long term benefits over PPA regarding arm pain and clinical signs associated with neurological deficits in chronic WAD.

Exercise, headache, and factors associated with headache in chronic whiplash: Analysis of a randomized clinical trial

BACKGROUND

Almost 40% of individuals with chronic whiplash-associated disorders (WAD) report headache after 5 years, making it one of the most common persistent symptoms besides neck pain, but randomized treatment studies are lacking. This study aimed to evaluate the effect of 3 different exercise approaches on headache in chronic WAD grades 2 and 3, and to identify potential factors associated with such headache, and whether they differ depending on 3 different aspects of such headache (current headache, maximum headache, or headache bothersomeness).

METHODS

This was an analysis of a randomized clinical trial of people with chronic WAD and headache (n = 188), who were randomized to either 12 weeks of neck-specific exercise without (NSE) or with a behavioral approach (NSEB) or physical activity prescription (PPA). Data were collected at baseline and at 3, 6, and 12 months. Physical and psychosocial factors were tested for association with headache. Multivariate regression models and linear mixed models were used.

RESULTS

The NSE/NSEB groups reported reduced headache both over time and compared to PPA. Up to 51% (NSE) and 61% (NSEB) reported at least 50% reduction in their headache at 12 months. The PPA group was not improved over time. Neck pain and dizziness were associated with headache regardless of aspect of headache. The only associated psychosocial factor was anxiety, which was associated with headache bothersomeness. Other factors were mainly physical, and up to 51% of the variance was explained.

CONCLUSION

Headache in chronic WAD, may be reduced with neck-specific exercise with or without a behavioral approach. Chronic headache was associated with neck pain and dizziness regardless of aspect tested. Other factors associated with headache in chronic WAD were mainly physical rather than psychosocial.

TRIAL REGISTRATION NUMBER

Clinical Trials.gov, no: NCT015285.

Ultrasound imaging of dorsal neck muscles with speckle tracking analyses - the relationship between muscle deformation and force

The development of methods of non-invasive measurement of neck muscle function remains a priority in the clinical sciences. In this study, dorsal neck muscle deformation vs time curves (deformation area) were evaluated against incremental force, recorded from non-invasive real-time ultrasound measurement. The results revealed subject-specific moderate to strong linear or non-linear relationships between deformation and force. Test-retest variability showed strong reliability for all five neck muscles summed together and fair to good reliability for the five muscles evaluated separately. Multivariate statistics were used to analyse the interactions between the dorsal neck muscles during different percentages of maximal voluntary contraction (MVC). Low force (10-20% MVC) was related to muscle shortening; higher force (40-80% MVC) showed combination of shortening and elongation deformation in the muscle interactions. The muscle interactions during isometric MVC test were subject-specific, with different combinations and deformations of the five neck muscles. Force ≥40% MVC were associated with a forward movement of the cervical spine that affected the ultrasound measurement of the dorsal neck muscles. Ultrasound with speckle-tracking analyses may be best used to detect low levels (<40% MVC) of neck muscle activity.

Pathophysiology behind prolonged whiplash associated disorders: study protocol for an experimental study

BACKGROUND

There is insufficient knowledge of pathophysiological parameters to understand the mechanism behind prolonged whiplash associated disorders (WAD), and it is not known whether or not changes can be restored by rehabilitation. The aims of the projects are to investigate imaging and molecular biomarkers, cervical kinaesthesia, postural sway and the association with pain, disability and other outcomes in individuals with longstanding WAD, before and after a neck-specific exercise intervention. Another aim is to compare individuals with WAD with healthy controls.

METHODS

Participants are a sub-group (n = 30) of individuals recruited from an ongoing randomized controlled study (RCT). Measurements in this experimental prospective study will be carried out at baseline (before intervention) and at a three month follow-up (end of physiotherapy intervention), and will include muscle structure and inflammation using magnetic resonance imaging (MRI), brain structure and function related to pain using functional MRI (fMRI), muscle function using ultrasonography, biomarkers using samples of blood and saliva, cervical kinaesthesia using the "butterfly test" and static balance test using an iPhone app. Association with other measures (self-reported and clinical measures) obtained in the RCT (e.g. background data, pain, disability, satisfaction with care, work ability, quality of life) may be investigated. Healthy volunteers matched for age and gender will be recruited as controls (n = 30).

DISCUSSION

The study results may contribute to the development of improved diagnostics and improved rehabilitation methods for WAD.

TRIAL REGISTRATION

Clinicaltrial.gov Protocol ID: NCT03664934, initial release 09/11/2018.

The effect of three exercise approaches on health-related quality of life, and factors associated with its improvement in chronic whiplash-associated disorders: analysis of a randomized controlled trial

Purpose

The aim was to evaluate whether neck-specific exercise, with (NSEB) or without (NSE) a behavioural approach, improves health-related quality of life (HRQoL) compared to physical activity prescription (PPA) in chronic whiplash-associated disorders (WAD) grades 2 and 3. A secondary aim was to identify factors associated with HRQoL and HRQoL improvement following exercise interventions.

Methods

This is a secondary analysis of a multicentre randomized clinical trial. Participants (n = 216) with chronic WAD grades 2 and 3 were randomized to 12 weeks of PPA or physiotherapist-led NSE or NSEB. The EQ-5D 3L/EQ-VAS and SF-36v2 physical (PCS) and mental (MCS) component summaries were collected together with several neck-related and psychosocial outcomes at baseline, after 3, 6 and 12 months, and were analysed with linear mixed models (all time points) and multivariate linear regressions (baseline, 6 months).

Results

NSE/NSEB resulted in better outcomes than PPA (EQ-VAS and SF-36 PCS, both groups, p < 0.01) but not in a higher EQ-5D score. Improvement over time was seen in EQ-5D/EQ-VAS for the NSEB group (p < 0.01), and for NSE/NSEB as measured with the PCS (p < 0.01). Factors associated with baseline HRQoL and change to 6 months in HRQoL (R² = 0.38–0.59) were both neck-related and psychosocial (e.g. depression, work ability).

Conclusion

Neck-specific exercise, particularly with a behavioural approach, may have a more positive impact on HRQoL than physical activity prescription in chronic WAD grades 2 and 3. HRQoL is however complex, and other factors also need to be considered. Factors associated with HRQL and improvements in HRQoL following exercise are multidimensional.

Trial registration number: ClinicalTrials.gov, No. NCT01528579.

Electronic supplementary material

The online version of this article (10.1007/s11136-018-2004-3) contains supplementary material, which is available to authorized users.

Neck-specific exercise may reduce radiating pain and signs of neurological deficits in chronic whiplash - Analyses of a randomized clinical trial

Up to 90% of people with neurological deficits following a whiplash injury do not recover and cervical muscle dysfunction is common. The aim of this multicentre, randomized controlled trial was to examine whether two versions of neck-specific exercise or prescription of physical activity (PPA) can improve radiating arm pain and clinical signs that can be associated with neurological deficits in people with chronic whiplash associated disorders (WAD). Participants with chronic WAD, arm symptoms and signs associated with neurological deficits (n = 171) were randomized to: 12 weeks of neck-specific exercise without (NSE) or with a behavioural approach (NSEB), or PPA. Pain/bothersomeness frequency, six measures of arm pain/paraesthesia (VAS scales), and four clinical neurological tests were evaluated after 3 months. The NSE group reported the lowest frequency and lowest levels of arm pain, the highest proportion of participants with at least 50% pain reduction and the highest proportion of normal arm muscle force. The NSEB group reported increased normal tendon reflexes. No improvements were recorded for the PPA group. Neck-specific exercise may improve arm pain and decrease signs of neurological deficits, but the addition of a behavioural approach does not seem to be of additional benefit.

Neck-specific exercise improves impaired interactions between ventral neck muscles in chronic whiplash: A randomized controlled ultrasound study

Chronic pain and disability is common in whiplash-associated disorders (WAD), leading to personal suffering, sick leave, and social cost. The cervical spine is heavily dependent on muscular support and whiplash injury can cause damage to the neck muscles, but diagnostic tools to measure neck muscle impairment and evaluate exercise interventions are lacking. Therefore, the present study investigated ventral neck muscle interactions in 26 individuals with chronic WAD randomized to neck-specific exercise (NSE) or remaining on a waiting list (WL) in 3 months. We performed real-time, non-invasive ultrasound measurements with speckle tracking analysis and calculated the deformation area and deformation rate in three ventral neck muscles. Multivariate statistics were used to analyse interactions between the muscles. After 3 months of NSE, significant improvements were observed in neck muscle interactions and pain intensity in the NSE group compared to the WL group. Thus, this study demonstrates that non-invasive ultrasound can be a diagnostic tool for muscle impairment and used to evaluate exercise interventions in WAD and stands to make a breakthrough for better management in chronic WAD.

Identifying the mechanical and neural properties of the sternocleidomastoid muscles

Neck muscles are preferentially activated in specific force directions, but the constraints that the central nervous system considers when programming these preferred directions of muscle activity are unknown. The current study used ultrasound shear wave elastography (SWE) to investigate whether the material properties of the sternocleidomastoid (SCM) muscles exhibit preferred directions similar to their preferred direction of muscle activity during an isometric task. Twenty-four healthy participants matched isometric forces in 16 axial directions. All force targets were scaled to 20% of a maximum voluntary contraction. Muscle activity was recorded with surface electromyography (EMG) from six muscles (the bilateral SCMs, upper trapezius, and splenius capitis muscles), and shear wave velocities (SWVs) were recorded with SWE from both SCM muscles. We observed statistically significant differences between the preferred directions of muscle activity and SWVs for both the left SCM ( P = 0.002) and the right SCM ( P < 0.001), with the SWE data exhibiting a more lateral preferred direction. Significant differences in the spatial focus ( P < 0.001) were also observed, with the dispersion of SWV data covering a greater angular range than the EMG data during isometric tasks. The preferred directions of muscle activity and material properties for the SCM muscles were closer than previous comparisons of muscle activity and moment arms, suggesting muscle mechanics could play a more important role than anatomy in how the central nervous system spatially tunes muscle activation. NEW & NOTEWORTHY Our study used a novel combination of surface electromyography and ultrasound shear wave elastography to investigate the neuromuscular control of the neck. Our work highlights differences in how the activation and material properties of the sternocleidomastoid muscles are modulated as the central nervous system stabilizes the neck during isometric force production. These findings provide normative data for future studies to investigate pathologic changes to both the activation and material properties of the sternocleidomastoid muscles.

Neck-specific exercises with internet-based support compared to neck-specific exercises at a physiotherapy clinic for chronic whiplash-associated disorders: study protocol of a randomized controlled multicentre trial

Background

Globally, neck pain is the fourth most common condition associated with longer periods of living with disability. Annually, approximately 0.3% of the population of Western countries undergo whiplash trauma, and half of those individuals will develop chronic problems with high costs for the individual and society. Evidence for chronic whiplash-associated disorders (WAD) treatment is scarce, though neck-specific training at a physiotherapy clinic twice a week for 12 weeks has demonstrated good results. More efficient, flexible rehabilitation with reduced waiting times and lower costs is needed, ideally replacing lengthy on-site treatment series by healthcare providers. Internet-based care has been shown to be a viable alternative for a variety of diseases and interventions, but studies are lacking on Internet-based interventions for individuals with chronic neck problems. The aim of the trial described here is to compare the effects of an Internet-based neck-specific exercise programme to the same exercises performed at a physiotherapy clinic in regards to self-reported and clinical measures, as well as cost-effectiveness.

Methods

This prospective, randomized controlled trial will involve 140 participants. Measurements will be made at baseline, 3 months (end of treatment), and 15 months (12 months after end of intervention) and will include ratings of pain, disability, satisfaction with care, work ability, quality of life, and cost-effectiveness.

Discussion

The study results may contribute to the development of a more effective rehabilitation, flexible and equal care, shorter waiting times, increased availability, and lower costs for healthcare and society.

Trial registration

ClinicalTrials.gov Protocol ID: NCT03022812, initial release 12/20/2016.

Alterations in the Mechanical Response of Deep Dorsal Neck Muscles in Individuals Experiencing Whiplash-Associated Disorders Compared to Healthy Controls: An Ultrasound Study

OBJECTIVE

The aim of this study was to investigate and compare the mechanical responses of dorsal neck muscles in individuals with whiplash-associated disorders (WAD) versus healthy individuals.

DESIGN

This study included 36 individuals with WAD (26 women and 10 men) and 36 healthy controls (26 women and 10 men). Ultrasound imaging with speckle tracking was used to measure deformation and deformation rate in five dorsal neck muscles during a neck extension task.

RESULTS

Compared with controls, individuals with WAD showed higher deformations of the semispinalis cervicis (P = 0.02) and multifidus (P = 0.002) muscles and higher deformation rates (P = 0.03 and 0.0001, respectively). Among individuals with WAD, multifidus deformation and deformation rate were significantly associated with pain, disability, and fatigue (r = 0.31-0.46, P = 0.0001-0.01).

CONCLUSIONS

These findings indicate that the mechanical responses of the deep dorsal neck muscles differ between individuals with WAD and healthy controls, possibly reflecting that these muscles use altered strategies while performing a neck extension task. This finding provides new insight into neck muscles pathology in patients with chronic WAD and may help improve rehabilitation programs.

TO CLAIM CME CREDITS

Complete the self-assessment activity and evaluation online at http://www.physiatry.org/JournalCME CME OBJECTIVES: Upon completion of this article, the reader should be able to: (1) Summarize the mechanical responses of dorsal neck muscles during loading of the neck muscles via an extension task in individuals with chronic whiplash associated disorders and healthy volunteers; (2) Differentiate mechanical responses between five dorsal neck muscles while loading the neck via an extension task; and (3) Describe the relationships between the mechanical responses of the dorsal neck muscles with the patients' perception of neck pain, disability, and fatigue.

LEVEL

Advanced ACCREDITATION: The Association of Academic Physiatrists is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.The Association of Academic Physiatrists designates this Journal-based CME activity for a maximum of 0.5 AMA PRA Category 1 Credit(s)™. Physicians should only claim credit commensurate with the extent of their participation in the activity.

Cost-effectiveness of neck-specific exercise with or without a behavioral approach versus physical activity prescription in the treatment of chronic whiplash-associated disorders: Analyses of a randomized clinical trial

BACKGROUND

Fifty percent of people injured by whiplash still report neck pain after 1 year and costs associated with whiplash associated disorders (WAD) are mostly attributed to health service and sick-leave costs in chronic conditions. With increasing health care expenditures the economic impact of interventions needs to be considered.

OBJECTIVE

To analyze the cost-effectiveness of physiotherapist-led neck-specific exercise without (NSE) or with a behavioral approach (NSEB), or prescription of physical activity (PPA) in chronic WAD, grade 2 to 3.

METHODS

This is a secondary cost-effectiveness analysis of a multicenter randomized clinical trial of 216 participants with chronic WAD grade 2 to 3. The interventions were physiotherapist-led neck-specific exercise without or with a behavioral approach, or prescription of physical activity for 12 weeks. Incremental cost-effectiveness ratios (ICERs) were determined after 1 year and bootstrapped cost-effectiveness planes and sensitivity analyses of physiotherapy visits were performed. Health care and production loss costs were included and quality-adjusted life years (QALYs) were estimated, using the Euroqol-5D questionnaire. Comparisons with the Short Form-6D, and neck disability index (NDI) were also made.

RESULTS

The 1-year follow-up was completed by 170 participants (79%). Both physiotherapist-led groups improved in health related quality of life. The intervention cost alone, per quality-adjusted life year (QALY) gain in the NSE group was US$ 12,067. A trend for higher QALY gains were observed in the NSEB group but the costs were also higher. The ICERs varied depending on questionnaire used, but the addition of a behavioral approach to neck-specific exercise alone was not cost-effective from a societal perspective (ICER primary outcome $127,800 [95% confidence interval [CI], 37,816-711,302]). The sensitivity analyses confirmed the results. The prescription of physical activity did not result in any QALY gain and the societal costs were not lower.

CONCLUSION

Neck-specific exercise was cost-effective from a societal perspective in the treatment of chronic WAD compared with the other exercise interventions. ICERS varied depending on health-related quality of life questionnaires used, but the addition of a behavioral approach was not cost-effective from a societal perspective. The prescription of physical activity did not result in any QALY gain and was thus not considered a relevant option.

Multivariate analysis of ultrasound-recorded dorsal strain sequences: Investigation of dynamic neck extensions in women with chronic whiplash associated disorders

Whiplash Associated Disorders (WAD) refers to the multifaceted and chronic burden that is common after a whiplash injury. Tools to assist in the diagnosis of WAD and an increased understanding of neck muscle behaviour are needed. We examined the multilayer dorsal neck muscle behaviour in nine women with chronic WAD versus healthy controls during the entire sequence of a dynamic low-loaded neck extension exercise, which was recorded using real-time ultrasound movies with high frame rates. Principal component analysis and orthogonal partial least squares were used to analyse mechanical muscle strain (deformation in elongation and shortening). The WAD group showed more shortening during the neck extension phase in the trapezius muscle and during both the neck extension and the return to neutral phase in the multifidus muscle. For the first time, a novel non-invasive method is presented that is capable of detecting altered dorsal muscle strain in women with WAD during an entire exercise sequence. This method may be a breakthrough for the future diagnosis and treatment of WAD.

Changes in Dorsal Neck Muscle Function in Individuals with Chronic Whiplash-Associated Disorders: A Real-Time Ultrasound Case-Control Study

Impaired neck muscle function leads to disability in individuals with chronic whiplash-associated disorder (WAD), but diagnostic tools are lacking. In this study, deformations and deformation rates were investigated in five dorsal neck muscles during 10 arm elevations by ultrasonography with speckle tracking analyses. Forty individuals with chronic WAD (28 women and 12 men, mean age = 37 y) and 40 healthy controls matched for age and sex were included. The WAD group had higher deformation rates in the multifidus muscle during the first (p < 0.04) and 10th (only women, p < 0.01) arm elevations compared with the control group. Linear relationships between the neck muscles for deformation rate (controls: R(2) = 0.24-0.82, WAD: R(2) = 0.05-0.74) and deformation of the deepest muscles (controls: R(2) = 0.61-0.32, WAD: R(2) = 0.15-0.01) were stronger for women in the control group versus women with WAD, indicating there is altered interplay between dorsal neck muscles in chronic WAD.