Chronic trauma-induced neck pain impairs the neural control of the deep semispinalis cervicis muscle

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 role of the deep cervical extensor muscles in multi-directional isometric neck strength

Clinical management of whiplash-associated disorders is challenging and often unsuccessful, with over a third of whiplash injuries progressing to chronic neck pain. Previous imaging studies have identified muscle fat infiltration, indicative of muscle weakness, in the deep cervical extensor muscles (multifidus and semispinalis cervicis). Yet, kinematic and muscle redundancy prevent the direct assessment of individual neck muscle strength, making it difficult to determine the role of these muscles in motor dysfunction. The purpose of this study was to determine the effects of deep cervical extensor muscle weakness on multi-directional neck strength and muscle activation patterns. Maximum isometric forces and associated muscle activation patterns were computed in 25 test directions using a 3-joint, 24-muscle musculoskeletal model of the head and neck. The computational approach accounts for differential torques about the upper and lower cervical spine. To facilitate clinical translation, the test directions were selected based on locations where resistance could realistically be applied to the head during clinical strength assessments. Simulation results reveal that the deep cervical extensor muscles are active and contribute to neck strength in directions with an extension component. Weakness of this muscle group leads to complex compensatory muscle activation patterns characterized primarily by increased activation of the superficial extensors and deep upper cervical flexors, and decreased activation of the deep upper cervical extensors. These results provide a biomechanistic explanation for movement dysfunction that can be used to develop targeted diagnostics and treatments for chronic neck pain in whiplash-associated disorders.

The Effect of C2 Muscular Exposure Technique on Radiographic and Clinical Outcomes After C2-T2 Posterior Cervical Fusion

STUDY DESIGN

Retrospective cohort analysis.

OBJECTIVE

To determine whether the C2 exposure technique was a predictor of change in cervical alignment and patient-reported outcomes measures (PROMs) after posterior cervical decompression and fusion (PCDF) for degenerative indications.

BACKGROUND

In PCDF handling of the C2 posterior paraspinal musculature during the operative approach varies by surgeon technique. To date, no studies have investigated whether maintenance of the upper cervical semispinalis cervicis attachments as compared with complete reflection of upper cervical paraspinal musculature from the posterior bony elements is associated with superior radiographic and clinical outcomes after PCDF.

PATIENTS AND METHODS

All adult patients who underwent C2-T2 PCDF for myelopathy or myeloradiculopathy at multi-institutional academic centers between 2013 and 2020 were retrospectively identified. Patients were dichotomized by the C2 exposure technique into semispinalis preservation or midline muscular reflection groups. Preoperative and short and long-term postoperative radiographic outcomes (upper cervical alignment, global alignment, and fusion status) and PROMs (Visual Analog Scale-Neck, Neck Disability Index, and Short Form-12) were collected. Univariate analysis compared patient factors, radiographic measures, and PROMs across C2 exposure groups.

RESULTS

A total of 129 patients met the inclusion/exclusion criteria (73 muscle preservation and 56 muscle reflection). Patients in the muscular preservation group were on average younger (P= 0.005) and more likely to have bone morphogenic protein (P< 0.001) and C2 pars screws (P= 0.006) used during surgery. Preoperative to postoperative changes in C2 slope, C2 tilt, C2-C3 segmental lordosis, C2-C3 listhesis, C0-C2 Cobb angle, proximal junctional kyphosis, ADI, C1 lamina-occiput distance, C2 sagittal vertical axis, C2-C7 lordosis, and PROMs at all follow-up intervals did not vary significantly by C2 exposure technique. Likewise, there were no significant differences in fusion status, C2-C3 pseudoarthrosis, C2 screw loosening, and complication and revision rates between C2 exposure groups.

CONCLUSIONS

Preservation of C2 semispinalis attachments versus muscular reflection did not significantly impact cervical alignment, clinical outcomes, or proximal junction complications in long-segment PCDF.

LEVEL OF EVIDENCE

Level III.

Effect of long-term cervical extensor exercise program on functional disability, pain intensity, range of motion, cervical muscle mass, and cervical curvature in young adult population with chronic non-specific neck pain: a randomized controlled trial

BACKGROUND

The prevalence of chronic non-specific neck pain (CNNP) is on the rise among the young adult population. We herein aimed to compare the effects of long-term specific cervical extensor training and stretching exercises on improving this chronic disorder in young adults.

METHODS

In this prospective, randomized, controlled study, 70 participants aged 18-35 years with CNNP and cervical lordosis loss were included. The participants were assigned to undergo either specific cervical extensor training (observation group) or perform usual stretching exercises (control group). The exercise duration was set at 12 months, with 9 months at the clinic and 3 months at home. The outcome assessments included changes in the neck disability index, visual analog scale from baseline, cervical range of motion (CROM), cross-sectional areas (CSAs) of cervical extensors, and cervical curvature from baseline. The outcome measures were compared between groups at 3, 6, and 12 months of follow-up.

RESULTS

All 70 participants underwent randomization, and no significant differences in demographics and baseline data were found between the two groups. The observation group showed a greater improvement in neck disability index and visual analog scale scores at the 12-month follow-up than the control group. Additionally, a more substantial increase in CROM and CSAs of cervical extensors was observed in the observation group at the 6-month and 12-month follow-ups (P < 0.05). Although more participants in the observation group achieved cervical lordosis at the 12-month follow-up, the difference was marginally nonsignificant (9% in the control group vs. 28% in the observation group, P = 0.075).

CONCLUSIONS

In young adults with CNNP, long-term specific cervical extensor training was associated with a more significant clinically meaningful improvement in disability, pain, and CROM than stretching exercises. The increased CSAs of cervical extensors may potentially contribute to the restoration of cervical lordosis. Trial registration The study is registered at the Chinese domestic clinical trial (ChiCTR2000040009) at Chictr.org. The date of registration: November 18, 2020.

Exercise therapy including the cervical extensor muscles in individuals with neck pain: A systematic review

OBJECTIVE

To review the use (dosage parameters and combination with other therapeutic interventions) of cervical extensor muscle exercises and their effect on pain, disability (primary outcomes), range of motion, endurance and strength (secondary outcomes) in people with neck pain.

DATA SOURCES

An extensive literature search was conducted through MEDLINE (Ovid), Scopus (Elsevier) and Physiotherapy Evidence Database (PEDro) up to May 2023. The reference lists of all included studies and relevant reviews were screened for additional studies.

REVIEW METHODS

Randomised controlled trials reporting the use of cervical extensor muscle exercises (alone or combined) applied to adults with idiopathic or traumatic neck pain were included. Study selection, data extraction and critical appraisal (PEDro assessment scale) were performed by two blinded reviewers. Data extraction included dosage parameters, other modalities combined with these exercises and outcomes.

RESULTS

Thirty-five randomised controlled trails (eight of which were complementary analyses) with 2409 participants fulfilled the inclusion criteria. Twenty-six were of moderate to high quality. In most studies, cervical extensor muscle exercises were combined with various other therapeutic modalities and applied at different dosages. Only two studies (one high and one low quality) specifically assessed their effectiveness. The high-quality study showed significant improvements in neck pain and disability, pressure point threshold and neck mobility after both low load and high load training for 6 weeks.

CONCLUSION

The results suggest cervical extensor muscle exercises may reduce neck pain and disability; however firm conclusions cannot be drawn because of the few studies that addressed this question and the heterogeneity of the dosage parameters.

Relationship Between C2 Semispinalis Cervicis Preservation and C2 Spinous Process Morphology During Cervical Laminoplasty Involving C3

STUDY DESIGN

Retrospective study.

OBJECTIVES

Due to anatomical variations in the semispinalis cervicis insertion in the C2 spinous process, complete preservation is not always possible when the C3 level is included in a cervical laminoplasty. Three-dimensional computed tomography was used to evaluate the relationship between the incidence of semispinalis cervicis injury and the C2 inter-spinous angle.

METHODS

We included 95 patients who underwent a cervical laminoplasty that included a C3 laminectomy for cervical myelopathy. Patients with a C2 inter-spinous angle above and below 60° were classified into wide- and narrow-angled groups, respectively (n = 48 and n = 47). Whether the C2 semispinalis cervicis insertion was preserved, or detached and reattached was reviewed from surgical records. The pre and postoperative C2-C7 lordosis and range of motion (ROM) were measured, and clinical outcomes were obtained from the patient charts.

RESULTS

The C2 semispinalis cervicis was preserved in 47 patients (97.9%) in the wide-angled group but only in 14 patients (29.8%) in the narrow-angled group (P < .001). The postoperative C2-C7 lordosis extension and ROM were significantly greater in the wide-angled (P = .048 and .036). Postoperative neck pain was significantly greater in the narrow-angled (P = .018).

CONCLUSIONS

The morphology of the C2 spinous process indicates that a C2 semispinalis cervicis insertion preservation is possible during a cervical laminoplasty that includes a C3 laminectomy. A careful surgical procedure should be conducted when the C2 inter-spinous angle is above 60° to increase the likelihood of achieving this preservation and thereby obtaining a more favorable clinical outcomes.

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.

Axioscapular and neck extensor muscle behavior during isometric shoulder exertions in patients with nonspecific neck pain with and without a scapular downward rotation posture

BACKGROUND

A common observation in persons with neck pain is scapular downward rotation (SDR) with altered muscle behavior. Evidence of changes in axioscapular muscles in neck pain patients remains inconclusive, which may reflect population heterogeneity in previous studies.

RESEARCH QUESTION

Are there differences in behavior of the axioscapular (upper trapezius: UT, lower trapezius: LT and serratus anterior: SA) and neck extensor (NE) muscles during isometric shoulder tasks in patients with neck pain with SDR, patients with no scapular dysfunction and healthy controls?

METHODS

Sixty participants with nonspecific neck pain (30 with SDR and 30 without scapular dysfunction) and 30 controls were recruited. Electromyographic signals were recorded unilaterally from the UT, LT, SA and NE during different isometric shoulder tasks (30° flexion, 30°abduction and 30°external rotation) at 20%, 50% and 100% maximal voluntary contraction (MVC). Activity of UT, LT, SA and NE was normalized with respect to reference contractions. The UT/LT, UT/SA and LT/SA ratios were calculated for each task.

RESULTS

The neck pain group with SDR had increased UT activity in 30°flexion (20%MVC) and 30°abduction (20% and 50%MVC) compared to the neck pain and control groups without scapular dysfunction (p < 0.05). There were no between group differences in LT and SA activity (p > 0.05). The neck pain groups had greater NE activity in all tasks (p < 0.001). Finally, the neck pain group with SDR had higher UT/LT and UT/SA ratios in a few tasks at low force levels (p ≤ 0.01).

SIGNIFICANCE

Greater UT activity and UT/LT and UT/SA ratios during particularly low force isometric shoulder tasks suggest that SDR is associated with altered axioscapular motor control. Greater NE activity in both neck pain groups suggests altered motor control related to neck pain. Changes in the NE and UT behavior should be considered in management of patients with neck pain with observable SDR.

Specific versus non-specific exercises for the neck extensor muscles in women with chronic idiopathic neck pain: A randomized controlled trial

BACKGROUND

Structural and functional impairments of the cervical extensor muscles have been demonstrated in people with neck pain. A global exercise approach targeting all neck extensor muscles has shown positive effects in this population. However, to date, the efficacy of exercises specifically targeting the deep neck extensors has neither been tested nor compared to global exercises for the neck extensors.

OBJECTIVES

To compare the effects on pain and disability of a specific lower deep neck extensors (SLDNE) versus a general neck extensor (GNE) exercise program in women with chronic idiopathic neck pain.

METHODS

Fourty-three women with chronic idiopathic neck pain were randomly allocated to either a six-week SLDNE or a GNE exercise program. As primary outcome, neck disability was measured with the Neck Disability Index (NDI). Secondarily, pain intensity (VAS), cervical ROM, pressure pain thresholds (PPTs), cervical and thoracic posture and self-perceived benefit of treatment (GROC) were also measured. Every outcome was measured at baseline and immediately after treatment, except NDI, which was also measured at 6-months follow-up. The GROC was only assessed post-intervention.

RESULTS

Both exercise programs lead to reduced neck disability immediately post-intervention (within-group mean difference [MD] = -6.09; 95% Confidence Interval [CI]: 7.75, -4.42 and -4.73; 95%CI: 6.57, -2.91 respectively) and at the 6-months follow-up (-4.47; 95%CI: 6.41, -2.53 and -4.74; 95%CI: 6.50, -2.97), but with no between group differences. Similar results were found for pain intensity post-intervention, with no between group interaction (within-group MD = -20.87 mm; 95% CI: 28.55, -13.19 and -18.00 mm; 95%CI: (-26.24, -9.76) for SLDNE and GNE groups, respectively). GROC improved after both interventions without any between-group difference.

CONCLUSIONS

A six-week exercise program specifically targeting the lower deep neck extensors lead to comparable outcomes as a general neck extensor exercise program in women with chronic idiopathic neck pain.

Features and impact of dysphagia, dysphonia and laryngeal hypersensitivity in whiplash associated disorder - a qualitative study

PURPOSE

Investigation into dysphagia, dysphonia and laryngeal hypersensitivity after whiplash is limited, offering minimal insight into specific features and impact. This study aimed to explore these symptoms.

MATERIALS AND METHODS

A qualitative interpretive description design was used. Eleven participants with chronic Whiplash Associated Disorder and self-reported swallowing, voice and/or throat-related problems completed baseline symptom questionnaires and were offered a videofluroscopic swallow study to investigate baseline swallowing biomechanics. Semi-structured interviews were conducted to explore features of swallowing, voice and laryngeal sensory complaints and analysed using thematic analysis.

RESULTS

There were high baseline levels of self-reported neck, pain- and throat-related disability and psychological distress. There was no evidence of baseline deficits in swallow biomechanics. Thematic analysis revealed 5 themes: (1) A range of features of dysphagia and dysphonia exist after whiplash with varied clinical course; (2) Activity and participation in swallow and voice activities have changed; (3) There are psychological and emotional impacts; (4) Features of laryngeal hypersensitivity co-exist and (5) There are barriers to management.

CONCLUSIONS

Swallow, voice and laryngeal sensory problems after whiplash were described, with impacts on quality of life and barriers to management. These insights broaden understanding of post-whiplash sequalae, indicating the need for better detection.Implications for rehabilitationDysphagia, dysphonia and laryngeal hypersensitivity are under-recognised consequences of whiplash.Individuals presenting with dysphagia, dysphonia and laryngeal sensory symptoms after whiplash experience significant implications to wellbeing, activity and participation.Improved understanding of these symptoms may facilitate better detection and subsequent referral to speech-language pathology.Greater understanding into the functional and psychosocial implications of these symptoms may guide more effective post-whiplash assessments and informed rehabilitation.

Assessment of Neuromuscular and Psychological Function in People with Recurrent Neck Pain during a Period of Remission: Cross-Sectional and Longitudinal Analyses

The aim of this study was to examine for the presence of differences in neuromuscular and psychological function in individuals with recurrent neck pain (RNP) or chronic neck pain (CNP) following a whiplash trauma compared to healthy controls. A secondary aim was to examine whether neuromuscular characteristics together with psychological features in people with RNP were predictive of future painful episodes. Multiple features were assessed including neck disability, kinesiophobia, quality of life, cervical kinematics, proprioception, activity of superficial neck flexor muscles, maximum neck flexion and extension strength, and perceived exertion during submaximal contractions. Overall, those with RNP (n = 22) and CNP (n = 8) presented with higher neck disability, greater kinesiophobia, lower quality of life, slower and irregular neck movements, and less neck strength compared to controls (n = 15). Prediction analysis in the RNP group revealed that a higher number of previous pain episodes within the last 12 months along with lower neck flexion strength were predictors of higher neck disability at a 6-month follow-up. This preliminary study shows that participants with RNP presented with some degree of altered neuromuscular features and poorer psychological function with respect to healthy controls and these features were similar to those with CNP. Neck flexor weakness was predictive of future neck disability.

[Feeling stiff…but what does it mean objectively? : Can you measure muscle tension?]

Almost everyone is familiar with "tense muscles", but what is muscle tension physiologically behind? Are tense muscles more active; do they have problems relaxing? Are they harder or stiffer than asymptomatic muscles? In this work, current evidence regarding the activity and stiffness of tense neck muscles is presented. Further, measurement methods and their limitations are explained. These limitations reveal the shortcomings of the current knowledge and the need for further research. Finally, a recently funded research project on the measurement of tense muscles is presented.

The effect of therapeutic exercise and vegan diet on pain and quality of life in young female patients with chronic non-specific neck pain

Background and purpose

In recent years, dietary practices have begun to be used in painful conditions. This study aimed to investigate the effect of a vegan diet and therapeutic exercise in patients with chronic non-specific neck pain.

Materials and methods

A total of 45 young female patients with chronic non-specific neck pain, aged 18–25 years, participated in the study. Body mass index and body fat percentage were measured with bioelectrical impedance analysis. Pain severity was assessed using the Visual Analogue Scale, quality of life with the short form-36 scale, kinesiophobia with the Tampa scale of kinesiophobia and neck disability with the Neck Disability Index.

Results

The pain severity reduced in the diet group and exercise group after treatment (p = 0.001). After treatment, Neck Disability Index score decreased in the diet group and exercise group (p = 0.001). Tampa scale of kinesiophobia score decreased in the diet group and exercise group (p = 0.001). The eight domains of the short form-36 scale score increased in the diet group and exercise group (p < 0.05). No difference was found in the body mass index and fat percentage in all groups before and after treatment (p˃ 0.05).

Conclusion

A vegan diet and therapeutic exercise are beneficial to patients with chronic non-specific neck pain in terms of pain severity and quality of life.

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.

Effects of Global Postural Reeducation versus Specific Therapeutic Neck Exercises on Pain, Disability, Postural Control, and Neuromuscular Efficiency in Women with Chronic Nonspecific Neck Pain: Study Protocol for a Randomized, Parallel, Clinical Trial

Background: Chronic nonspecific neck pain is the most frequent form of neck pain. It is more prevalent in women, and a costly public health issue. It is commonly associated with biomechanical, functional, proprioceptive, and postural impairments. The aim of this trial is to compare the effects of global postural exercises versus specific therapeutic exercises on neck pain, disability, mobility, pressure pain threshold, kinesiophobia, pain catastrophizing, postural control, and neuromuscular efficiency in women with chronic nonspecific neck pain. Methods and analysis: This study is a randomized, parallel-group and single blinded clinical trial. Sixty-two women with nonspecific chronic neck pain were recruited from the community of Guarda, Portugal, and randomly assigned to one of two intervention groups: (1) global postural reeducation (GPR group), (2) specific therapeutic exercises (STE group). The intervention was carried out over 4 weeks, with two sessions per week (eight sessions), and applied by a physiotherapist and paired with a daily individual at-home-exercise program. Primary outcomes are neck pain intensity and disability (Numerical Pain Rating Scale, Neck Disability Index). Secondary outcomes are cervical mobility and pressure pain threshold (CROM, algometry), attitude to pain (kinesiophobia, pain catastrophizing), standing postural control (Center of Pressure (COP) displacements), and neuromuscular efficiency (electromyography). There are four points of evaluation where the outcomes were assessed twice before the intervention, 1 week apart, and the two post-intervention assessments will be carried out after four and eight sessions. The objective was to increase scientific knowledge of different exercise modalities, such as global postural reeducation, in musculoskeletal disorders. Trial registration: ClínicalTrials.gov (NCT04402463), prospectively registered (data 22 May 2020).

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.

Sexual dimorphism of the posterior cervical spine muscle attachments

Cervical spinal injury and neck pain are common disorders with wide physical implications. Neck pain and disability are reported to occur in females more often than in males, and chronic or persistent neck pain after whiplash is twice as common in females. Female athletes also sustain a higher percentage of concussions compared to male athletes. Still, while sexual differences in clinical presentation and outcome are well-established, the underlying etiology for the disparity remains less clear. It is well-established that the origin and insertion landmarks of posterior neck muscles are highly variable, but we do not know if these interindividual differences are associated with sex. Expanding our knowledge on sexual dimorphism in the anatomy of the cervical muscles is essential to our understanding of the possible biomechanical differences between the sexes and hence improves our understanding as to why females suffer from cervical pain more than males. It is also of paramount importance for accurate planning of posterior cervical spine surgery, which cuts through the posterior cervical musculature. Therefore, our main objective is to characterize the anatomy of posterior neck musculature and to explore possible sexual differences in the location of their attachment points. Meticulous posterior neck dissection was performed on 35 cadavers, 19 females, and 16 males. In each specimen, 8 muscle groups were examined bilaterally at 45 osseous anatomical landmarks. Muscles and their attachment sites were evaluated manually then photographed and recorded using Microscribe Digitizer technology built into 3D models. A comparison of attachment landmarks between males and females for each muscle was conducted. Out of the eight muscles that were measured, only two muscles demonstrated significant sex-related anatomical differences-Spinotranversales (splenius capitis and cervicis) and Multifidus. Male Spinotransversales muscle has more attachment points than female. It showed more cranial insertion points in the upper cervical attachments (superior nuchal line, C1 posterior tubercle, and mastoid process) and more caudal insertion points in the spinous processes and transverse processes of the lower cervical and upper thoracic vertebrae. Thus, the male subjects in this study exhibited a greater coverage of the posterior neck both cranially and caudally. Female Multifidus has more attachment points on the spinous processes and articular processes at middle and lower cervical vertebrae and at the transverse processes of the upper thoracic vertebrae. All remaining muscles exhibited no sexual differences. Our findings highlight, for the first time, a sexual dimorphism in attachment points of posterior cervical musculature. It reinforces the notion that the female neck is not a scaled version of the male neck. These differences in muscle attachment could partially explain differences in muscle torque production and range of motion and thus biomechanical differences in cervical spine stabilization between sexes. It sheds a much-needed light on the reason for higher whiplash rates, concussion, and chronic cervical pain among females. Surgeons should take these sexual morphological differences into consideration when deliberating the best surgical approach for posterior cervical surgery.

Regular swimming exercise prevented the acute and persistent mechanical muscle hyperalgesia by modulation of macrophages phenotypes and inflammatory cytokines via PPARγ receptors

Physically active individuals are less likely to develop chronic pain, and physical exercise is an established strategy to control inflammatory diseases. Here, we hypothesized that 1) peripheral pro-inflammatory macrophages phenotype contribute to predisposition of the musculoskeletal to chronic pain, and that 2) activation of PPARγ receptors, modulation of macrophage phenotypes and cytokines through physical exercise would prevent persistent muscle pain. We tested these hypotheses using swimming exercise, pharmacological and immunochemical techniques in a rodent model of persistent muscle hyperalgesia. Swimming prevented the persistent mechanical muscle hyperalgesia most likely through activation of PPARγ receptors, as well as activation of PPARγ receptors by 15d-PGJ₂ and depletion of muscle macrophages in sedentary animals. Acute and persistent muscle hyperalgesia were characterized by an increase in pro-inflammatory macrophages phenotype, and swimming and the 15d-PGJ₂ prevented this increase and increased anti-inflammatory macrophages phenotype. Finally, IL-1β concentration in muscle increased in the acute phase, which was also prevented by PPARγ receptors activation through swimming. Besides, swimming increased muscle concentration of IL-10 in both acute and chronic phases, but only in the persistent phase through PPARγ receptors. Our findings suggest physical exercise activates PPARγ receptors and increases anti-inflammatory responses in the muscle tissue by modulating macrophages phenotypes and cytokines, thereby preventing the establishment of persistent muscle hyperalgesia. These results further highlight the potential of physical exercise to prevent chronic muscle pain.

Muscle network topology analysis for the classification of chronic neck pain based on EMG biomarkers extracted during walking

Neuromuscular impairments are frequently observed in patients with chronic neck pain (CNP). This study uniquely investigates whether changes in neck muscle synergies detected during gait are sensitive enough to differentiate between people with and without CNP. Surface electromyography (EMG) was recorded from the sternocleidomastoid, splenius capitis, and upper trapezius muscles bilaterally from 20 asymptomatic individuals and 20 people with CNP as they performed rectilinear and curvilinear gait. Intermuscular coherence was computed to generate the functional inter-muscle connectivity network, the topology of which is quantified based on a set of graph measures. Besides the functional network, spectrotemporal analysis of each EMG was used to form the feature set. With the use of Neighbourhood Component Analysis (NCA), we identified the most significant features and muscles for the classification/differentiation task conducted using K-Nearest Neighbourhood (K-NN), Support Vector Machine (SVM), and Linear Discriminant Analysis (LDA) algorithms. The NCA algorithm selected features from muscle network topology as one of the most relevant feature sets, which further emphasize the presence of major differences in muscle network topology between people with and without CNP. Curvilinear gait achieved the best classification performance through NCA-SVM based on only 16 features (accuracy: 85.00%, specificity: 81.81%, and sensitivity: 88.88%). Intermuscular muscle networks can be considered as a new sensitive tool for the classification of people with CNP. These findings further our understanding of how fundamental muscle networks are altered in people with CNP.

Cervical Proprioception Impairment in Neck Pain-Pathophysiology, Clinical Evaluation, and Management: A Narrative Review

Neck pain is very common, but most of the causes are unknown, making diagnosis and treatment extremely challenging. Current studies have found that one of the main problems in patients with neck pain is the impairment of cervical proprioception, which subsequently leads to cervical sensorimotor control disturbances. Cervical spine has a very delicate proprioceptive system that plays a crucial role in controlling posture and balance. Cervical proprioceptive impairment in neck pain occurs through a variety of mechanisms. Experimental neck muscle pain induced by injection of hypertonic saline results in inhibition of the activation of painful muscle; chronic neck pain causes structural and functional impairment of cervical muscles; excessive activation of mechanoreceptors in degenerative cervical discs and facet joints produces a large number of erroneous sensory signals. Clinical examinations to assess the link between structural pathology and neck pain have been unsuccessful, opening the way for the development of function-based tests. To date, eight neck sensorimotor control tests have been reported to evaluate patients with chronic neck pain. Although some tests may involve different subsystems (such as oculomotor system and vestibular system), all tests measure sensorimotor control in the neck, and the most commonly used is cervical joint position error (JPE) test. Current studies support the effectiveness of exercises targeting different aspects of sensorimotor function, in particular retraining aimed at improving cervical proprioception and muscle coordination. Based on the available evidence, it is recommended that patients with neck pain should be assessed and managed for cervical proprioceptive impairment and sensorimotor control disturbances.

Macromolecular changes in spinal cord white matter characterize whiplash outcome at 1-year post motor vehicle collision

Each year, whiplash injuries from motor vehicle collisions (MVC) affect millions worldwide, with no strong evidence of pathology. While the majority recover soon after the injury, the same is not true for roughly 20% reporting higher levels of pain and distress, without diagnostic options. This study used magnetization transfer (MT) imaging to quantify white matter integrity in 78 subjects with varying levels of pain, 1 year after MVC. MT images of the cervical spinal cord were collected parallel to the intervertebral disks. MT ratios (MTR) were calculated in select white matter tracts along with MTR homogeneity (MTRh) at each level. Significant differences were observed between clinical outcome groups in the left and right spinothalamic tracts (p = 0.003 and 0.020) and MTRh (p = 0.009). MTRh was elevated in females with poor recovery versus females reporting recovery (p < 0.001) or milder symptoms (p < 0.001), and in males reporting recovery (p = 0.007) or no recovery (p < 0.001). There was a significant interaction between recovery status and sex (p = 0.015). MT imaging identified tract specific and regional changes in white matter integrity suggesting potential insults to the cord. Additionally, significant MTRh differences between sexes were observed, characterizing the heterogeneity of whiplash recovery and worse outcomes in females.

Upper cervical spine dysfunction and dizziness

Although various causes of dizziness have been identified, many patients suffer from dizziness of unknown etiology and continue to visit hospitals to resolve their symptoms. Problems that occur in the ligaments or muscles of the upper cervical spine can cause confusion in proprioception. These changes can convey misinformation to the vestibular nucleus, resulting in abnormal reactions that can lead to cervicogenic dizziness (CGD). Though CGD remains controversial, it should be considered while diagnosing patients with dizziness. Understanding CGD can help create treatment strategies for them. This article suggested a relationship between the structure and function of the upper cervical spine and dizziness, and presented evaluations and treatments for the same.

The Relationship of Ultrasound Measurements of Muscle Deformation With Torque and Electromyography During Isometric Contractions of the Cervical Extensor Muscles

OBJECTIVES

Speckle tracking analysis (STA) of ultrasound (US) images quantifies the longitudinal deformation of a region of muscle tissue to provide a mechanical measure of muscle activity. As the validity and reliability of this method has not yet been adequately assessed, the aim of this study was to determine the validity and reliability of STA in the dorsal neck muscles during isometric neck extension contractions.

METHODS

Twenty volunteers performed 3 repetitions of isometric neck extension in a dynamometer at 10%, 20%, 40%, 60%, and 80% of maximal voluntary torque while US and surface electromyography (EMG) data were recorded. Speckle tracking analysis was then used to calculate measurements of muscle deformation. The relationship among torque, muscle deformation (separate for each muscle and summed), and EMG was evaluated using linear regressions and Spearman's correlation coefficients. The reliability of EMG and muscle deformation was determined using intraclass correlation coefficients (ICCs).

RESULTS

Muscle deformation in 4 of the 5 muscles when examined separately and collectively was significantly related to torque (P < .05); however, the relationship was weak (r² = 0.03-0.18). In contrast, a strong linear relationship was observed between torque and EMG (P < .001, r² = 0.83). Poor to moderate reliability of muscle deformation measures (ICC: 0.02-0.69) was found compared with EMG, which was highly reliable (ICC: 0.67-0.90).

CONCLUSION

These results suggest that the validity of US STA measurements for isometric contractions of the dorsal neck muscles is questionable. Further investigation into this method is required before it can be used as a tool to measure muscle activity.

Confirming the geography of fatty infiltration in the deep cervical extensor muscles in whiplash recovery

Previous preliminary work mapped the distribution of neck muscle fat infiltration (MFI) in the deep cervical extensor muscles (multifidus and semispinalis cervicis) in a small cohort of participants with chronic whiplash associated disorders (WAD), recovered, and healthy controls. While MFI was reported to be concentrated in the medial portion of the muscles in all participants, the magnitude was significantly greater in those with chronic WAD. This study aims to confirm these results in a prospective fashion with a larger cohort and compare the findings across a population of patients with varying levels of WAD-related disability one-year following the motor vehicle collision. Sixty-one participants enrolled in a longitudinal study: Recovered (n = 25), Mild (n = 26) and Severe WAD (n = 10) were studied using Fat/Water magnetic resonance imaging, 12-months post injury. Bilateral measures of MFI in four quartiles (Q1–Q4; medial to lateral) at cervical levels C4 through C7 were included. A linear mixed model was performed, controlling for covariates (age, sex, body mass index), examining interaction effects, and comparing MFI distribution between groups. The recovered group had significantly less MFI in Q1 compared to the two symptomatic groups. Group differences were not found in the more lateral quartiles. Results at 12 months are consistent with the preliminary study, indicating that MFI is spatially concentrated in the medial portions of the deep cervical extensors regardless of WAD recovery, but the magnitude of MFI in the medial portions of the muscles is significantly larger in those with severe chronic WAD.

Muscle fat infiltration following whiplash: A computed tomography and magnetic resonance imaging comparison

Here we present a secondary analysis from a parent database of 97 acutely injured participants enrolled in a prospective inception cohort study of whiplash recovery after motor vehicle collision (MVC). The purpose was to investigate the deep and superficial neck extensor muscles with peri-traumatic computed tomography (CT) and longitudinal measures of magnetic resonance imaging (MRI) in participants with varying levels of whiplash-related disability. Thirty-six underwent standard care imaging of the cervical spine with CT at a level-1 trauma designated emergency department. All 36 participants were assessed with MRI of the cervical spine at <1-week, 2-weeks, 3-, and 12-months post-injury and classified into three groups using initial pain severity and percentage scores on the Neck Disability Index (recovered (NDI of 0–8%), mild (NDI of 10–28%), or severe (NDI ≥ 30%)) at 3-months post MVC. CT muscle attenuation values were significantly correlated to muscle fat infiltration (MFI) on MRI at one-week post MVC. There was no significant difference in muscle attenuation across groups at the time of enrollment. A trend of lower muscle attenuation in the deep compared to the superficial extensors was observed in the severe group. MFI values in the deep muscles on MRI were significantly higher in the severe group when compared to the mild group at 1-year post MVC. This study provides further evidence that the magnitude of 1) deep MFI appears unique to those at risk of and eventually transitioning to chronic WAD and that 2) pre- or peri-traumatic muscular health, determined by CT muscle attenuation, may be contribute to our understanding of long-term recovery.

Neck Muscle Stiffness Measured With Shear Wave Elastography in Women With Chronic Nonspecific Neck Pain

OBJECTIVE

Utilizing shear wave elastography, we compared the stiffness of the neck extensor muscles and the stiffness in muscle-specific regions between women with chronic nonspecific neck pain and asymptomatic controls.

DESIGN

Cross-sectional observational study.

METHODS

We measured the average muscle stiffness over multiple neck extensor muscles and in regions corresponding approximately to the trapezius, splenius capitis, semispinalis capitis, semispinalis cervicis, and multifidus muscles using ultrasound shear wave elastography in 20 women with chronic nonspecific neck pain and 18 asymptomatic women during multiple tasks. The measurements were automatically quality controlled and computer processed over the complete visible neck region or a large muscle-specific region.

RESULTS

Pooled over all tasks, neck muscle stiffness was not significantly different between those with neck pain and asymptomatic controls (neck pain median, 11.6 kPa; interquartile range, 8.9 kPa and control median, 13.3 kPa; interquartile range, 8.6 kPa; P = .175). The measure of neck muscle stiffness was not correlated with the intensity of neck pain or perceived disability.

CONCLUSION

Shear wave elastography revealed similar muscle stiffness in people with and without chronic neck pain, despite the sensation of increased neck stiffness in those with chronic neck pain. Therapeutic interventions aiming to reduce neck muscle tone are often based on the assumption that perceived neck stiffness corresponds to objective muscle stiffness. The current results question this assumption. J Orthop Sports Phys Ther 2020;50(4):179-188. Epub 6 Jan 2020. doi:10.2519/jospt.2020.8821.

Motor vehicle crash reconstruction: Does it relate to the heterogeneity of whiplash recovery?

Whiplash injury is a common consequence of motor vehicle crashes (MVC), yet it is also one of the most poorly understood. While more than 50% of those injured should expect to rapidly recover, others are not as fortunate with approximately 25% of those exposed to and injured in an MVC transitioning from acute to chronic pain and disability. The purpose of this prospective study was to determine if the severity and direction of collisions involving participants enrolled in a longitudinal study of recovery from whiplash are able to differentiate between different recovery groups based on the neck disability index (NDI) percentage scores at 3-months, and if these crash specific parameters are associated with known risk factors for recovery. Here, we examined objective collision data, repair invoices, and characteristics of the crash for 37 acutely injured participants consented and enrolled at their emergency department visit and further assessed at three time points; < 1 week, 2-weeks, and 3-months post MVC. Collision data were used to reconstruct and estimate the severity of the crash and determine if they aligned with the heterogeneity of whiplash injury recovery. Wilcoxon rank sum tests were used to determine if % scores on the Neck Disability Index (NDI) at 3-months post MVC were associated with the following variables: sex, head turned at time of impact, seatbelt use, whether or not airbags deployed, if the vehicle was struck while stopped or while turning, or the principle direction of force (PDOF). Spearman’s correlation coefficients were used to determine if NDI at 3-months post MVC was associated with age, Body Mass Index, pain-related disability at baseline, signs of post-traumatic distress, intrusion/hyperarousal, negative affect, pain intensity, estimated speed change from the impact, and damage estimates (in US$). There was a significant positive association between self-reported neck disability at 3-months post MVC, post-traumatic distress, negative affect and uncontrolled pain. There was no direct effect of participant characteristics, arousal, intrusion/hyperarousal sub-score, damage, PDOF, speed change, or other crash characteristics. Established crash parameters were not associated with the heterogeneity of whiplash injury recovery in a small sample of injured participants.

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.

Whiplash-Associated Dysphagia: Considerations of Potential Incidence and Mechanisms

Non-specific self-reports of dysphagia have been described in people with whiplash-associated disorders (WAD) following motor vehicle collision (MVC); however, incidence and mechanistic drivers remain poorly understood. Alterations in oropharyngeal dimensions on magnetic resonance imaging (MRI), along with heightened levels of stress, pain, and changes in stress-dependent microRNA expression (e.g., miR-320a) have been also associated with WAD, suggesting multi-factorial issues may underpin any potential swallowing changes. In this exploratory paper, we examine key biopsychosocial parameters in three patients with persistent WAD reporting swallowing change and three nominating full recovery after whiplash with no reported swallowing change. Parameters included (1) oropharyngeal volume with 3D MRI, (2) peritraumatic miR-320a expression, and (3) psychological distress. These factors were explored to highlight the complexity of patient presentation and propose future considerations in relation to a potential deglutition disorder following WAD. The three participants reporting changes in swallowing all had smaller oropharyngeal volumes at < 1 week and at 3 months post injury and lower levels of peritraumatic miR-320a. At 3 months post MVC, oropharyngeal volumes between groups indicated a large effect size (Hedge's g = 0.96). Higher levels of distress were reported at both time points for those with persistent symptomatology, including self-reported dysphagia, however, this was not featured in those nominating recovery. This paper considers current evidence for dysphagia as a potentially under-recognized feature of WAD and highlights the need for future, larger-scaled, multidimensional investigation into the incidence and mechanisms of whiplash-associated dysphagia.

Cervical Rotator Muscle Activity With Eye Movement at Different Speeds is Distorted in Whiplash

BACKGROUND

People with whiplash-associated disorders (WADs) report difficulty with quick head movements and cervicoocular dysfunction. Changes in coordination between eye movement and neck muscle activity may be involved.

OBJECTIVE

To examine whether activity of superficial and deep neck muscles increases with eye movement when the head is held in a fixed position, whether this differs between directions and speed of eye movement, and whether this is modified in WAD.

DESIGN

Convenience case series with unmatched controls.

SETTING

Research laboratory.

PARTICIPANTS

Nine individuals with chronic WAD grade II and 11 pain-free controls.

METHODS

Electromyography (EMG) was recorded from muscles that could act to rotate the neck to the right (right obliquus capitis inferior [OI], multifidus [MF], splenius capitis [SC], and left sternocleidomastoid [SCM]) with intramuscular or surface electrodes in 9 WAD participants and 11 pain-free controls. Eyes were rotated without head movement to track slow and medium-speed targets to the right or left, and as fast as possible (FP).

MAIN OUTCOME MEASUREMENTS

Amplitude of EMG.

RESULTS

In controls, SCM and SC EMG increased with right gaze (all P's < .03). EMG of the deep OI muscle increased in both directions (P < .001). WAD involved counterintuitive greater activity of SCM with left rotation across speeds of eye movement (SC with slow movement, P < .036), decreased OI EMG with gaze left (P < .019), and no change in MF EMG (P < .6) in either gaze direction. For FP tasks, EMG of all muscles was greater than slower speeds in controls (all P's < .0001), but not WAD (all P's > .33).

CONCLUSIONS

Coordination between neck muscle activity and eye movements with increasing speed is modified in WAD. Contrasting changes are present in deep and superficial neck muscles with implications for neck function that may explain some common WAD symptoms.

LEVEL OF EVIDENCE

IV.

Comparative Strength and Endurance Parameters of the Craniocervical and Cervicothoracic Extensors and Flexors in Females With and Without Idiopathic Neck Pain

Isometric strength and endurance performance of cervical flexor and extensor muscles were compared in women with (n = 30) and without (n = 30) idiopathic neck pain at the craniocervical and cervicothoracic axes. Strength and endurance time (time to task failure in seconds) at 50% maximal voluntary contraction were recorded in 4 directions (craniocervical flexion/extension and cervicothoracic flexion/extension) and 6 strength and endurance ratios were calculated. Participants in both groups were matched for body mass index. The idiopathic neck pain group demonstrated significantly less strength for the cervicothoracic flexors and extensors (1.58-4.7 N·m [12.4%-17.9%] less, P < .04) and significantly less endurance time for the cervicothoracic and craniocervical flexors (10.77-10.9 s [23.3%-27.5%] less, P < .03). The cervicothoracic extension to craniocervical flexion strength ratio was also lower in the idiopathic neck pain group (P = .01); however, no other strength or endurance ratio was significantly different between groups. This exploratory study suggests assessing specific performance parameters accounting for regional muscular differences in the upper and lower neck is potentially informative to understanding impairments in neck pain conditions, particularly as impairments may not be uniform across muscle groups.

Adoption of a research-based program for neck disorders implemented in primary care physiotherapy: a short- and long-term follow-up survey study

Neck disorders are common in primary health care (PHC) physiotherapy. A neck-specific exercise program based on research findings was implemented among physiotherapists in Swedish PHC. The aim of the study was to evaluate the adoption of the program. We invited PHC physiotherapists to an educational session including theoretical information and practical training. Before the educational session the participants (n = 261) completed a baseline questionnaire. After 3 and 12 months, we distributed surveys to identify changes in practice and in confidence regarding diagnosis and treatment. We compared data from 3-months and 12-months follow-up, respectively, with baseline data. Self-reported frequency of most of the included assessment methods was unchanged after 12 months. Frequency of assessment of neck proprioception had increased significantly. Specific neck muscle exercise for treatment of whiplash associated disorders was applied more frequently after 3 and after 12 months than at baseline. Frequency of other treatment methods remained unchanged. Confidence in diagnosis and treatment increased significantly, particularly among women. The program was not adopted as expected, but resulted in increased confidence regarding diagnosis and treatment. The provision of a short educational session seemed not to be sufficient to obtain a sustained change in practice.

Effect of specific deep cervical muscle exercises on functional disability, pain intensity, craniovertebral angle, and neck-muscle strength in chronic mechanical neck pain: a randomized controlled trial

Background

Exercise is known to be an important component of treatment programs for individuals with neck pain. The study aimed to compare the effects of semispinalis cervicis (extensor) training, deep cervical flexor (flexor) training, and usual care (control) on functional disability, pain intensity, craniovertebral (CV) angle, and neck-muscle strength in chronic mechanical neck pain.

Methods

A total of 54 individuals with chronic mechanical neck pain were randomly allocated to three groups: extensor training, flexor training, or control. A Thai version of the Neck Disability Index, numeric pain scale (NPS), CV angle, and neck-muscle strength were measured at baseline, immediately after 6 weeks of training, and at 1- and 3 -month follow-up.

Results

Neck Disability Index scores improved significantly more in the exercise groups than in the control group after 6 weeks training and at 1- and 3-month follow-up in both the exten-sor (P=0.001) and flexor groups (P=0.003, P=0.001, P=0.004, respectively). NPS scores also improved significantly more in the exercise groups than in the control group after 6 weeks’ training in both the extensor (P<0.0001) and flexor groups (P=0.029. In both exercise groups, the CV angle improved significantly compared with the control group at 6 weeks and 3 months (extensor group, P=0.008 and P=0.01, respectively; flexor group, P=0.002 and 0.009, respectively). At 1 month, the CV angle had improved significantly in the flexor group (P=0.006). Muscle strength in both exercise groups had improved significantly more than in the control group at 6 weeks and 1- and 3-month follow-up (extensor group, P=0.04, P=0.02, P=0.002, respectively; flexor group, P=0.002, P=0.001, and 0.001, respectively). The semispinalis group gained extensor strength and the deep cervical flexor group gained flexor strength.

Conclusion

The results suggest that 6 weeks of training in both exercise groups can improve neck disability, pain intensity, CV angle, and neck-muscle strength in chronic mechanical neck pain.

Trial registration

NCT02656030

Relationship between cervical muscle morphology evaluated by MRI, cervical muscle strength and functional outcomes in patients with degenerative cervical myelopathy

BACKGROUND

Cervical muscle alterations have been reported in patients with chronic neck pain, but the assessment of muscle morphology and strength has been overlooked in patients with degenerative cervical myelopathy (DCM).

OBJECTIVES

This study aimed to investigate the relationship between cervical muscle degenerative changes observed on MRI, muscle strength and symptoms severity in patients diagnosed with DCM.

DESIGN

Observational study.

METHODS

Cervical muscle measurements of total cross-sectional area (CSA), functional CSA (fat free area, FCSA) and ratio of FCSA/CSA (e.g. fatty infiltration) were obtained from T2-weighted axial MR images from C2-C3 to C6-C7 in 20 patients. Muscle strength was assessed manually using a microFET2 dynamometer. The association between cervical muscle morphology parameters, muscle strength, symptoms severity and functional status was investigated.

RESULTS

Greater mean CSA and FCSA was associated with greater overall muscle strength. The mean FCSA explained 37%, 76%, 39%, 20% and 65% of the total variance in flexion, extension, right-side bending, left-side bending and overall muscle strength, respectively. The mean ratio of FCSA/CSA was not significantly associated with cervical muscle strength in any direction. However, greater FCSA/CSA ratio (e.g. less fatty infiltration) was associated with lower disability score (p = 0.02, R² = 0.20).

CONCLUSIONS

Cervical muscle lean muscle mass was positively associated with cervical muscle strength in patients with DCM. Moreover, greater fatty infiltration in the cervical extensor muscles was associated with lower functional score. Such findings suggest that clinicians should pay greater attention to cervical muscle morphology and function in patients with DCM.

Effects of deep cervical flexor training on impaired physiological functions associated with chronic neck pain: a systematic review

Background

Neck pain is a major health issue with high rates of recurrence. It presents with a variety of altered sensorimotor functions. Exercise is a cornerstone of rehabilitation and many training methods are used. Exercise is evaluated in most randomized controlled trials on its pain relieving effects. No review has assessed the effect of exercise on the altered physiological functions or determined if there are differential effects of particular training methods. This review investigated the effects of deep cervical flexor (DCF) training, a training method commonly used for patients with neck pain, and compared it to other training methods or no training on outcomes of cervical neuromuscular function, muscle size, kinematics and kinetics.

Methods

Web of Science, Scopus, CINAHL, PubMed were searched from inception until January 2018. Twelve randomized controlled trials were included that compared DCF training as sole intervention to other training or no interventions in persons with neck pain. The Cochrane Risk of Bias tool was used to assess the method quality. All outcome measures were analysed descriptively and meta-analyses were performed for measures evaluated in three or more studies.

Results

DCF training was compared to cervical endurance, strength, proprioception and mobility training, muscle stretching, and no intervention control groups. Physiological outcome measures included neuromuscular co-ordination (craniocervical flexion test), functional tasks, muscle fatigability, muscle size, kinematics (joint position sense, posture and range of motion) and kinetics (strength, endurance and contraction accuracy). Strong evidence was found for effectiveness of DCF training on neuromuscular coordination, but it had no or small effects on strength and endurance at higher loads. DCF training improved head and cervical posture, while evidence was limited or contradictory for other measures.

Conclusions

DCF training can successfully address impaired neuromuscular coordination, but not cervical flexor strength and endurance at higher contraction intensities. A multimodal training regime is proposed when the aim is to specifically address various impaired physiological functions associated with neck pain.

Temporomandibular disorder and comorbid neck pain: facts and hypotheses regarding pain-induced and rehabilitation-induced motor activity changes

According to the "pain adaptation model", temporomandibular disorder (TMD)-related pain induces a paradoxical activity of masticatory muscles: an agonistic hypoactivity during jaw closing and an antagonistic activity during jaw opening (agonist/antagonist co-activation). However, this model suffers several weaknesses; notably, it does not explain all types of neck muscle activities in neck pain (NP), which is a very prevalent TMD comorbid condition. In NP, neck muscle antagonistic activity is increased, and agonistic activity is decreased as postulated by the pain adaptation model. However, synergistic and compensatory activity may occur and agonistic activity may be unchanged or even increased as postulated within the "vicious cycle theory". Thus, both theories would apply partly as outlined currently in musculoskeletal disorders (MSD). Besides pain, psychological stress may also induce motor dysfunction in TMD and NP. In NP, rehabilitation may increase agonistic activity and decrease compensatory activity and antagonistic activity, thus inducing a switch from agonist/antagonist co-activation towards reciprocal inhibition. Thus, rehabilitation-induced motor activity changes constitute a new research field that should improve MSD therapeutics. Additionally, immature tongue function (so-called infantile swallow) might be connected to TMD where low agonistic activity of masticatory muscles would be compensated by facial muscle hyperactivity during oropharyngeal phase of deglutition.

Validation of an index of Sensitivity to Movement-Evoked Pain in patients with whiplash injuries

Introduction: Sensitivity to Movement-Evoked Pain is a pain summation phenomenon identified in various chronic pain populations. Objectives: This study investigated the validity of a procedure used to assess pain summation in response to a repeated lifting task in individuals with whiplash injuries. Methods: Sixty-five participants completed measures of pain severity and duration, Temporal Summation (TS) of pinprick pain, pain catastrophizing and fear of movement, and work-related disability before lifting a series of 18 weighted canisters. An index of Sensitivity to Movement-Evoked Pain was computed as the increase in pain reported by participants over successive lifts of the weighted canisters. An index of TS was computed by dividing the pain reported in response to the final pinprick by the pain reported in response to the 1st pinprick in a train of 10 pinpricks. Results: Analyses replicated previous findings showing a repetitive lifting task-induced pain summation in approximately 20% to 25% of a sample of individuals with whiplash injuries. Analyses also revealed significant correlations between SMEP, TS, and pain-related psychological variables. Hierarchical regression analyses showed that TS and pain catastrophizing made significant unique contributions to the prediction of SMEP. These findings join a growing body of research on movement-evoked pain in persistent spinal pain conditions. Conclusion: The repeated lifting task used in this study successfully induced pain summation in a group of patients with whiplash injuries.

The qualitative grading of muscle fat infiltration in whiplash using fat and water magnetic resonance imaging

BACKGROUND CONTEXT

The development of muscle fat infiltration (MFI) in the neck muscles is associated with poor functional recovery following whiplash injury. Custom software and time-consuming manual segmentation of magnetic resonance imaging (MRI) is required for quantitative analysis and presents as a barrier for clinical translation.

PURPOSE

The purpose of this work was to establish a qualitative MRI measure for MFI and evaluate its ability to differentiate between individuals with severe whiplash-associated disorder (WAD), mild or moderate WAD, and healthy controls.

STUDY DESIGN/SETTING

This is a cross-sectional study.

PATIENT SAMPLE

Thirty-one subjects with WAD and 31 age- and sex-matched controls were recruited from an ongoing randomized controlled trial.

OUTCOME MEASURES

The cervical multifidus was visually identified and segmented into eighths in the axial fat/water images (C4-C7). Muscle fat infiltration was assessed on a visual scale: 0 for no or marginal MFI, 1 for light MFI, and 2 for distinct MFI. The participants with WAD were divided in two groups: mild or moderate and severe based on Neck Disability Index % scores.

METHODS

The mean regional MFI was compared between the healthy controls and each of the WAD groups using the Mann-Whitney U test. Receiver operator characteristic (ROC) analyses were carried out to evaluate the validity of the qualitative method.

RESULTS

Twenty (65%) patients had mild or moderate disability and 11 (35%) were considered severe. Inter- and intra-rater reliability was excellent when grading was averaged by level or when frequency of grade II was considered. Statistically significant differences (p<.05) in regional MFI were particularly notable between the severe WAD group and healthy controls. The ROC curve, based on detection of distinct MFI, showed an area-under-the curve of 0.768 (95% confidence interval 0.59-0.94) for discrimination of WAD participants.

CONCLUSIONS

These preliminary results suggest a qualitative MRI measure for MFI is reliable and valid, and may prove useful toward the classification of WAD in radiology practice.

Effects of lumbar lordosis assistive support on craniovertebral angle and mechanical properties of the upper trapezius muscle in subjects with forward head posture

[Purpose] The aim of this study was to investigate the effect of lumbar lordosis assistive support (LLAS) on craniovertebral angle (CVA) and mechanical properties of the upper trapezius (UT) muscle in subjects with forward head posture (FHP). [Subjects and Methods] This study recruited 20 subjects with FHP. CVA and muscle tone, viscoelasticity, and stiffness of the UT were measured using Myoton in all subjects in a sitting position with LLAS and in a neutral sitting position. The order of measurements was randomized and the mean values were calculated twice. [Results] The sitting position with LLAS showed a significantly greater improvement than the neutral sitting position with regard to CVA and muscle tone, viscoelasticity, and stiffness of the UT. [Conclusion] We suggest that the sitting position using LLAS induces the maintenance of normal neck posture and a reduction in the muscle tone of the UT in the subjects with FHP.

Responsiveness of clinical tests for people with neck pain

BACKGROUND

Responsiveness of a clinical test is highly relevant in order to evaluate the effect of a given intervention. However, the responsiveness of clinical tests for people with neck pain has not been adequately evaluated. The objective of the present study was to examine the responsiveness of four clinical tests which are low cost and easy to perform in a clinical setting, including the craniocervical flexion test, cervical active range of movement, test for the cervical extensors and pressure pain threshold testing.

METHODS

This study is a secondary analysis of data collected in a previously published randomised controlled trial. Participants were randomized to either physical training, exercises and pain education combined or pain education only. Participants were tested on the clinical tests at baseline and at 4-month follow-up. An anchor-based approach using Receiver Operator Characteristics (ROC) curves was used to evaluate responsiveness of the clinical tests. The Neck Disability Index was used to discriminate between those who had improved and those who were unchanged at the 4-month follow-up. Minimum Clinically Important Difference (MCID), together with sensitivity, specificity, positive and negative predictive values, in addition to positive and negative likelihood ratios were calculated.

RESULTS

In total, 164 participants completed the 4 month follow up. One-hundred forty four participants were classified as unchanged whereas 20 patients were considered to be improved. Twenty-six participants didn't complete all of the clinical tests, leaving a total of 138 to be included for analyses. Area Under Curve (AUC) ranged from 0.50-0.62 for the clinical tests, and were all below an acceptable level. MCID was generally large, and the corresponding sensitivity and specificity was low with sensitivity ranging from 20 to 60%, and specificity from 54 to 86%. LR+ (0.8-2.07) and LR- (0.7-1.1) showed low diagnostic value for all variables, with PPV ranging from 12.1 to 26.1 and NPV ranging from 84.7 to 89.2.

CONCLUSION

Responsiveness of the included clinical tests was generally low when using change in NDI score as the anchor from baseline to the 4-month follow up. Further investigations of responsiveness are warranted, possibly using other anchors, which to a higher degree resemble similar dimensions as the clinical tests.

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.

Activation of the semispinalis cervicis and splenius capitis with cervical pulley exercises

STUDY DESIGN

Quasi-Experimental.

OBJECTIVE

To assess the activation of semispinalis cervicis (d-SSC) and splenius capitis (s-SC) muscles, and the activation between the two during neck pulley and free weight exercises.

BACKGROUND

Altered activation of cervical extensors may occur with neck pain, suggesting that exercises should be designed to target these muscles.

METHODS

d-SSC and s-SC activity was recorded unilaterally with intramuscular electromyography from healthy volunteers during cervical isometric exercises: 1) extension with a pulley rope angled from incline to vertical, 2) extension with right, left and central forehead hanging weight, and 3) rotation with pulley rope angled from incline to decline.

RESULTS

Extension against a vertical force led to greater activation of d-SSC (P < 0.001) and s-SC (P < 0.001) compared to the inclined, declined and horizontal pulley. With each of these conditions, amplitude of muscle activity was higher for the d-SSC compared to the s-SC muscle (P < 0.0001). Extension with free weight hanging on right, left or central forehead, showed no differences across conditions, although in each condition, the d-SSC amplitude was higher than the s-SC. For cervical rotation, the declined pulley led to the greatest activation of both muscles (P < 0.05). Higher levels of activity were observed for the s-SC compared to the d-SSC (P < 0.01) for all rotation conditions.

CONCLUSION

A vertical resistance during an extension exercise or a declined resistance during cervical rotation, increased neck extensor activation. The results from this preliminary study provide guidance for future work on the exploration and development of low-load exercise design for patients with neck pain disorders.

Immediate improvement in the cranio-cervical flexion test associated with MDT-based interventions: a case report

The patient in this case study presented with constant idiopathic neck pain and left lower scapular pain (greater than 3 months) and was treated based on the principles of Mechanical Diagnosis and Therapy (MDT). Retraction exercises produced centralization of the lower scapular pain to the upper part of the scapula at the initial visit. At the first visit, the performance level on the Cranio-Cervical Flexion Test (CCFT) was ≤20 mmHg before the treatment. At the conclusion of the treatment during which centralization occurred, the CCFT level improved to 24 mmHg. At the second visit, all symptoms were abolished and cervical range of motion (ROM) was fully restored by performing repeated extension in lying from a retracted position with clinician's traction. The CCFT levels before and immediately after the treatment were 24 and 26 mmHg, respectively. At the third visit (1 week after the initial visit), he noted that all daily activities could be performed without pain. The CCFT level was maintained at 26mmHg. The patient in this study showed immediate improvement in the CCFT through the treatments based on MDT. This suggests a possible link between MDT interventions and motor control of the cervical spine and a need to further investigate this relationship.

Advancements in Imaging Technology: Do They (or Will They) Equate to Advancements in Our Knowledge of Recovery in Whiplash?

Synopsis It is generally accepted that up to 50% of those with a whiplash injury following a motor vehicle collision will fail to fully recover. Twenty-five percent of these patients will demonstrate a markedly complex clinical picture that includes severe pain-related disability, sensory and motor disturbances, and psychological distress. A number of psychosocial factors have shown prognostic value for recovery following whiplash from a motor vehicle collision. To date, no management approach (eg, physical therapies, education, psychological interventions, or interdisciplinary strategies) for acute whiplash has positively influenced recovery rates. For many of the probable pathoanatomical lesions (eg, fracture, ligamentous rupture, disc injury), there remains a lack of available clinical tests for identifying their presence. Fractures, particularly at the craniovertebral and cervicothoracic junctions, may be radiographically occult. While high-resolution computed tomography scans can detect fractures, there remains a lack of prevalence data for fractures in this population. Conventional magnetic resonance imaging has not consistently revealed lesions in patients with acute or chronic whiplash, a "failure" that may be due to limitations in the resolution of available devices and the use of standard sequences. The technological evolution of imaging techniques and sequences eventually might provide greater resolution to reveal currently elusive anatomical lesions (or, perhaps more importantly, temporal changes in physiological responses to assumed lesions) in those patients at risk of poor recovery. Preliminary findings from 2 prospective cohort studies in 2 different countries suggest that this is so, as evidenced by changes to the structure of skeletal muscles in those who do not fully recover. In this clinical commentary, we will briefly introduce the available imaging decision rules and the current knowledge underlying the pathomechanics and pathophysiology of whiplash. We will then acknowledge known prognostic factors underlying functional recovery. Last, we will highlight emerging evidence regarding the pathobiology of muscle degeneration/regeneration, as well as advancements in neuroimaging and musculoskeletal imaging techniques (eg, functional magnetic resonance imaging, magnetization transfer imaging, spectroscopy, diffusion-weighted imaging) that may be used as noninvasive and objective complements to known prognostic factors associated with whiplash recovery, in particular, poor functional recovery. J Orthop Sports Phys Ther 2016;46(10):861-872. doi:10.2519/jospt.2016.6735.

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.