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

Cervical Multifidus Stiffness Assessment in Individuals with and without Unilateral Chronic Neck Pain: An Inter-Examiner Reliability Study

This study aimed to evaluate the inter-examiner reliability of shear wave elastography (SWE) for measuring cervical multifidus (CM) muscle stiffness in asymptomatic controls and patients with chronic neck pain. A longitudinal observational study was conducted to assess the diagnostic accuracy of a procedure. SWE images, following a detailed procedure previously tested, were acquired by two examiners (one novice and one experienced) to calculate the shear wave speed (SWS) and Young's modulus. The painful side was examined for the experimental cases while the side examined in the control group was selected randomly. Data analyses calculated the intra-class correlation coefficients (ICCs), absolute errors between examiners, standard errors of measurement, and minimal detectable changes. A total of 125 participants were analyzed (n = 54 controls and n = 71 cases). The Young's modulus and SWS measurements obtained by both examiners were comparable within the asymptomatic group (both, p > 0.05) and the chronic neck pain group (both, p > 0.05). Nonetheless, a notable distinction was observed in the absolute error between examiners for shear wave speed measurements among patients with neck pain, where a significant difference was registered (p = 0.045), pointing to a sensitivity in measurement consistency affected by the presence of chronic neck pain. ICCs demonstrated moderate-to-good reliability across both groups, with ICC values for asymptomatic individuals reported as >0.8. Among the chronic neck pain patients, ICC values were slightly lower (>0.780). The study revealed moderate-to-good consistency, highlighting the practicality and generalizability of SWE.

Is musculoskeletal pain associated with increased muscle stiffness? Evidence map and critical appraisal of muscle measurements using shear wave elastography

INTRODUCTION AND AIMS

Approximately 21% of the world's population suffers from musculoskeletal conditions, often associated with sensations of stiff muscles. Targeted therapy requires knowing whether typically involved muscles are objectively stiffer compared to asymptomatic individuals. Muscle stiffness is quantified using ultrasound shear wave elastography (SWE). Publications on SWE-based comparisons of muscle stiffness between individuals with and without musculoskeletal pain are increasing rapidly. This work reviewed and mapped the existing evidence regarding objectively measured muscle stiffness in musculoskeletal pain conditions and surveyed current methods of applying SWE to measure muscle stiffness.

METHODS

A systematic search was conducted in PubMed and CINAHL using the keywords "muscle stiffness", "shear wave elastography", "pain", "asymptomatic controls" and synonyms. The search was supplemented by a hand search using Google Scholar. Included articles were critically appraised with the AXIS tool, supplemented by items related to SWE methods. Results were visually mapped and narratively described.

RESULTS

Thirty of 137 identified articles were included. High-quality evidence was missing. The results comprise studies reporting lower stiffness in symptomatic participants, no differences between groups and higher stiffness in symptomatic individuals. Results differed between pain conditions and muscles, and also between studies that examined the same muscle(s) and pathology. The methods of the application of SWE were inconsistent and the reporting was often incomplete.

CONCLUSIONS

Existing evidence regarding the objective stiffness of muscles in musculoskeletal pain conditions is conflicting. Methodological differences may explain most of the inconsistencies between findings. Methodological standards for SWE measurements of muscles are urgently required.

The immediate effect of cervical rotation-traction manipulation on cervical paravertebral soft tissue: a study using soft tissue tension cloud chart technology

BACKGROUND

To evaluate the reliability of the Soft Tissue Tension Cloud Chart (STTCC) technology, an original method combining multi-point Cervical Paravertebral Soft Tissue Test (CPSTT) with MATLAB software, we conducted a preliminary analysis on the immediate effects of Orthopaedic Manual Therapy (OMT) on cervical paravertebral soft tissue.

METHODS

30 patients with Cervical Spondylotic Radiculopathy (CSR) were included in this study. We analyzed the differences in CPSTT before and after treatment with Cervical Rotation-Traction Manipulation (CRTM), a representative OMT technique in Traditional Chinese Medicine, using the STTCC technology.

RESULTS

The STTCC results demonstrated that post-treatment CPSTT levels in CSR patients were significantly lower than pre-treatment levels after application of CRTM, with a statistically significant difference (P < 0.001). Additionally, pre-treatment CPSTT levels on the symptomatic side (with radicular pain or numbness) were higher across the C5 to C7 vertebrae compared to the asymptomatic side (without symptoms) (P < 0.001). However, this difference disappeared after CRTM treatment (P = 0.231).

CONCLUSIONS

The STTCC technology represents a reliable method for analyzing the immediate effects of OMT. CSR patients display uneven distribution of CPSTT characterized by higher tension on the symptomatic side. CRTM not only reduces overall cervical soft tissue tension in CSR patients, but can also balance the asymmetrical tension between the symptomatic and asymptomatic sides.

TRIAL REGISTRATION

This study was approved by the Chinese Clinical Trials Registry (Website: . https://www.chictr.org.cn .) on 20/04/2021 and the Registration Number is ChiCTR2100045648.

Which muscles exhibit increased stiffness in people with chronic neck pain? A systematic review with meta-analysis

Introduction

Chronic neck pain (CNP) substantially impacts quality of life, posing both personal challenges and economic strains. This systematic review sought to discern muscle-specific stiffness differences between CNP patients and individuals without CNP.

Methods

We searched the PubMed, Scopus, and PEDro databases for studies using ultrasound elastography or myotonometry to compare muscle stiffness between CNP patients and asymptomatic controls. Using a meta-analysis with a random-effects model, we derived the pooled effect as standardized mean difference (SMD).

Results

Out of the six studies selected, the adjusted Newcastle-Ottawa rating scale for cross-sectional studies denoted three as moderate-quality and three as high-quality. Our findings indicate that the upper trapezius (UT) stiffness was elevated in CNP patients compared to their counterparts without CNP (SMD = 0.39, 95% CI = 0.05 to 0.74; p = 0.03; small effect size). The data for other muscles remained inconclusive.

Discussion

Given the case-control design of all reviewed studies, a direct causative link between UT stiffness and CNP is yet to be confirmed. As such, recommending a reduction in trapezius muscle stiffness as a primary rehabilitation strategy for CNP patients is still inconclusive and further research is needed.

Quality of Japanese Online Information on Causes of Neck Pain: A Biopsychosocial Analysis

Background While a considerable amount of information on neck pain is available online, the quality and comprehensiveness of this information can vary greatly. Particularly, the representation of the biopsychosocial model - which recognizes neck pain as an interplay of biological, psychological, and social factors - in online information remains unclear. Given the prevalence and accessibility of online health information, it is important to understand its quality and how it may shape individuals' understanding and management of neck pain. Therefore, the objective of this study was to analyze the quality of online Japanese information on the causes of neck pain from a biopsychosocial perspective. Methodology A descriptive cross-sectional study was conducted. The search term "neck pain" was utilized on Google's search engine in June 2023, and the websites from the first two pages of the search results were included in the study. Ten advertisement websites were excluded, resulting in 19 websites being analyzed. Each website was evaluated based on the presence of the Health-on-the-Net (HON) code. Biomedical and psychosocial factors present in each website were identified using the biopsychosocial analysis tool. Websites were then categorized as biomedical, limited biopsychosocial, or biopsychosocial based on the number of psychosocial factors they mentioned. Results Among the 19 evaluated websites, only one possessed the HON certification, indicating a potential lack of credibility for the remaining sites. Of these websites, a large majority (63.2%) were classified as biomedical, while the remaining (36.8%) were classified as limited biopsychosocial. All the websites included some form of biomedical information on the causes of neck pain, while only seven websites mentioned psychological factors and one website mentioned social factors. The most common biomedical causes of neck pain discussed were cervical muscle strain and radicular pain due to cervical disc prolapse. On the other hand, the limited biopsychosocial websites highlighted perceived stress, depressed mood, and job-related mental stress as psychosocial factors contributing to neck pain. Conclusions This analysis revealed that freely accessible Japanese online information on the causes of neck pain, as found through Google, predominantly focuses on the biomedical causes, often neglecting or insufficiently addressing the psychosocial aspects. This finding underscores a gap between the available online resources and the comprehensive understanding promoted by the biopsychosocial model of health. Healthcare professionals need to be proactive in guiding their patients toward reliable, well-rounded resources that acknowledge the crucial role of psychosocial factors in neck pain. Furthermore, developers of online health information must aim to improve the depth and breadth of psychosocial factors discussed, promoting a more holistic understanding of neck pain for the Japanese public.

Measuring Shear Wave Velocity in Adult Skeletal Muscle with Ultrasound 2-D Shear Wave Elastography: A Scoping Review

Ultrasound 2-D shear wave elastography (US 2D-SWE) is a non-invasive, cost-effective tool for quantifying tissue stiffness. Amidst growing interest in US 2D-SWE for musculoskeletal research, it has been recommended that shear wave velocity (SWV) should be reported instead of elastic moduli to avoid introducing unwanted error into the data. This scoping review examined the evolving use of US 2D-SWE to measure SWV in skeletal muscle and identified strengths and weaknesses to guide future research. We searched electronic databases and key review reference lists to identify articles published between January 2000 and May 2021. Two reviewers assessed the eligibility of records during title/abstract and full-text screening, and one reviewer extracted and coded the data. Sixty-six studies met the eligibility criteria, of which 58 were published in 2017 or later. We found a striking lack of consensus regarding the effects of age and sex on skeletal muscle SWV, and widely variable reliability values. Substantial differences in methodology between studies suggest a pressing need for developing standardized, validated scanning protocols. This scoping review illustrates the breadth of application for US 2D-SWE in musculoskeletal research, and the data synthesis exposed several notable inconsistencies and gaps in current literature that warrant consideration in future studies.

Cervical and axioscapular muscle stiffness measured with shear wave elastography: A comparison between different levels of work-related neck disability

Assessing muscle mechanical properties in terms of stiffness may provide important insights into mechanisms underlying work-related neck pain. This study compared stiffness of cervical and axioscapular muscles between 92 participants (sonographers) with no (n = 31), mild (n = 43) or moderate/severe (n = 18) neck disability. It was hypothesized that participants with more severe neck pain and disability would present with altered distribution of stiffness in cervical and axioscapular muscles than those with no disability. Using shear wave elastography, the shear modulus (kPa) of five cervical and six axioscapular muscles or muscle segments were measured in a relaxed seated upright or side-lying position. Muscle activity was measured simultaneously using surface electromyography during the elastography measurements and scapular depression was measured using a measurement tape and inclinometer before the elastography measurements to evaluate their potential confounding influences on shear modulus. Increased shear modulus was found in deeper than superficial cervical muscles and more cranial than caudal axioscapular muscles. However, no differences in shear modulus of the cervical or axioscapular muscles were found between sonographers with varying levels of disability. This study suggests no alterations in stiffness of cervical and axioscapular muscles were associated with work-related neck pain and disability.

Preliminary investigation of the effects of sitting with and without short active breaks on muscle stiffness assessed with shear-wave elastography

Purpose

The purpose of this preliminary study was to compare the effects of 1-h sitting with and without short active breaks on muscle stiffness as measured by shear-wave elastography (SWE).

Methods

The participants (7 females, 3 males; age: 24.9 ± 1.2 years) completed two (with and without active breaks) 1-h sitting exposures on separate days. Active breaks (2–3 min) were performed at 20 min and 40 min time marks and comprised simple stretching and activation exercises. Before, during (30 min) and after (1 h) of sitting, shear modulus of upper trapezius, lumbar region of erector spinae and rectus femoris muscles was measured with SWE.

Results

Statistically significant effects of sitting exposure in erector spinae muscle stiffness were noted (p = 0.041; η2 = 0.38). There were no other statistically significant effects of sitting exposure or condition (with/without breaks).

Conclusions

Although few statistically significant effects were detected, the trends in this preliminary trial suggest that prolonged sitting increases muscle stiffness and warrants further investigation of short active breaks with larger sample sizes.

Women with Chronic Pelvic Pain Demonstrate Increased Lumbopelvic Muscle Stiffness Compared to Asymptomatic Controls

Background: Although lumbopelvic muscle stiffness is commonly clinically assessed in women with chronic pelvic pain (CPP), it has not been objectively quantified in this population, and its association with other pain-related impairments has not yet been established. Objective: To compare superficial lumbopelvic muscle stiffness in women with and without CPP. In addition, pressure pain threshold (PPT) was compared between groups and the associations between muscle stiffness and PPT were assessed in women with CPP. Study Design: Case-control. Methods: Muscle stiffness and PPT of 11 lumbopelvic muscles were assessed in 149 women with CPP and 48 asymptomatic women. Subjective outcome measures, including pelvic floor function, health history, and psychosocial outcomes, were collected before muscle stiffness and PPT measurements. Analysis of covariance was used to compare muscle stiffness differences between groups, and independent t-tests were used to compare PPT between groups. Associations between measurements of PPT and muscle stiffness were calculated using correlation analysis. Results: Five of the 11 muscles measured were significantly stiffer in women with CPP than those without CPP (p < 0.05). PPT was significantly decreased in all muscles measured in women with CPP; however, there was not a significant association between muscle stiffness and PPT in women with CPP. Conclusion: The study identified the abdominal lumbopelvic muscles that have increased stiffness in women with CPP compared to asymptomatic women. In addition, muscle stiffness and PPT are two distinct impairments within this population. The results suggest that women with CPP have peripheral muscle impairments, which may be addressed without intravaginal or intrarectal intervention. Clinical Trial Registration: NCT04851730.

Specification of Neck Muscle Dysfunction through Digital Image Analysis Using Machine Learning

Everyone has or will have experienced some degree of neck pain. Typically, neck pain is associated with the sensation of tense, tight, or stiff neck muscles. However, it is unclear whether the neck muscles are objectively stiffer with neck pain. This study used 1099 ultrasound elastography images (elastograms) obtained from 38 adult women, 20 with chronic neck pain and 18 asymptomatic. For training machine learning algorithms, 28 numerical characteristics were extracted from both the original and transformed shear wave velocity color-coded images as well as from respective image segments. Overall, a total number of 323 distinct features were generated from the data. A supervised binary classification was performed, using six machine-learning algorithms. The random forest algorithm produced the most accurate model to distinguish the elastograms of women with chronic neck pain from asymptomatic women with an AUC of 0.898. When evaluating features that can be used as biomarkers for muscle dysfunction in neck pain, the region of the deepest neck muscles (M. multifidus) provided the most features to support the correct classification of elastograms. By constructing summary images and associated Hotelling's T² maps, we enabled the visualization of group differences and their statistical confirmation.

Description of Clinical Features and Diagnoses of 444 Cases with Neck-Shoulder-Upper Extremity Pain: A Single-Center Retrospective Review

PURPOSE

Neck-shoulder-upper extremity pain (NSUEP) is a frequently occurring clinical constellation of syndromes. However, its etiology is complicated, and the diagnosis is challenging. We aimed to present detailed clinical characteristics and diagnoses of NSUEP from a single center and heighten clinicians' understanding of this condition.

PATIENTS AND METHODS

Prospectively collected databases were used to retrospectively evaluate patients with NSUEP who underwent treatment at the multidisciplinary consultation center for neck, shoulder, and upper extremity pain at the China-Japan Union Hospital of Jilin University between April 2014 and July 2021. We performed descriptive statistics regarding demographic data, symptoms, findings of physical and radiographic examinations, and each patient's diagnosis.

RESULTS

Development of NSUEP was primarily observed in individuals aged between 51 and 60 years (n = 157, 35.4%). Patients were most commonly referred for upper extremity pain (n = 306, 68.9%). Patients with upper extremity pain presented with hypoesthesia (n = 139, 45.4%), muscle weakness (n = 93, 30.4%), muscle atrophy (n = 90, 29.4%), hyperesthesia (n = 39, 12.7%), and turgidity (n = 18, 5.9%). Among the 22 patients with upper extremity swelling, 8 (36.4%) were diagnosed with autoimmune rheumatic diseases. Among the 352 patients with a single diagnosis, 51 (14.5%) presented with thoracic outlet syndrome, 49 (13.9%) with cervical radiculopathy, 16 (4.5%) with carpal tunnel syndrome, and 16 (4.5%) with brachial plexus injury. Further, among the 92 patients with compound diagnosis, 18 patients (19.6%) were diagnosed with cervical radiculopathy.

CONCLUSION

Among the NSUEP patients in this study, older individuals were the largest group. Pain, numbness, weakness, and mobility limitation are common complaints accompanying NSUEP. The common etiologies of NSUEP include cervical spondylosis, thoracic outlet syndrome, carpal tunnel syndrome, and brachial plexus injury. In addition, autoimmune rheumatic diseases should be considered in patients with NSUEP and swelling.

Assessment of Neck Muscle Shear Modulus Normalization in Women with and without Chronic Neck Pain

Identifying the objective stiffness of the neck muscles facilitates the early and specific diagnosis of neck pain and targeted therapy. However, individual variation in the muscle shear modulus obscures differences between healthy and diseased individuals. Normalization may improve the comparability between individuals. The shear modulus at different functional tasks served as a reference for normalizing the neck muscles’ shear modulus of 38 women, 20 with chronic neck pain and 18 asymptomatic. Reference tasks were maximal voluntary contraction, relaxed sitting, prone head lift, balancing 1 kg on the head, and neck extension at 48 N. The effects of normalization on within-group variation and between-group differences were compared. Normalization with maximal voluntary contraction was discarded due to imaging problems. Normalization with relaxed sitting, prone head lift, balancing 1 kg, and neck extension at 48 N reduced within-group variation, by 23.2%, 26.8%, 11.6%, and 33.6%, respectively. All four normalization approaches reduced the p-values when testing for between-group differences. For the pain group, normalization with relaxed sitting and head lift indicated less normalized muscle stiffness, while normalization with balancing 1 kg and extension at 48 N indicated higher stiffness. The contradictory results are explainable by non-significant group differences in the reference tasks. Normalization of the muscle shear modulus is effective to reduce within-group variation, but a trustworthy normalization approach for group comparisons has yet to be identified.

[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.

Shear wave elastography of the scalene muscles in healthy adults: A preliminary study

The aim of the study is to evaluate the reliability of shear wave elastography to assess the anterior and middle scalene muscles in healthy adult subjects.The study included 60 scalene muscles in 15 healthy subjects. High-resolution ultrasound and shear wave elastography were used to evaluate the anterior scalene and the middle scalene muscles. Stiffness values were measured.The mean shear elastic modulus showed the following values, right anterior scalene muscle 18.83 ± 5.32 kPa, left anterior scalene muscle 21.71 ± 4.8 kPa, right middle scalene muscle 12.84 ± 5.2 kPa, left middle scalene muscle 19.76 ± 5.30 kPa. Positive correlation was noted between the left middle scalene muscle and body mass index (P = .004). No difference in elasticity was noted between the right and left anterior scalene muscles; however, significant difference was noted between the right and left middle scalene muscles (P = .002).The results obtained in our study could be a reference point for future research considering different scalene muscle pathologies.

Neck pain in rounded shoulder posture: Clinico-radiologic correlation by shear wave elastography

AIM

The frequency of neck pain increases in adolescents and young adults. Using smart phones and computers for a long time causes posture disorders such as rounded shoulder (RSP) and forward head postures, and these posture disorders cause neck pain. The aim of the study is to analyse the correlation between shoulder and neck angles and the stiffness of the upper trapezius and pectoralis minor muscles in patients with RSP.

METHOD

Patients with neck pain examined by shear wave elastography were screened retrospectively. Patients with RSP were determined. Of these patients, whose had evaluated for shoulder and neck angles with a smart phone-based photogrammetric method were assigned. Patients with a history of operation/trauma, connective tissue or neurological disease were excluded. A total of 39 female patients were included in the study. Age, height, weight, elastography measurements, cervical and shoulder angles were noted. Obtained data were statistically analysed with SPSS 22.0 program.

RESULTS

Cervical and shoulder angles of the patients were 52.2 ± 3.8 and 57.91 ± 9.4, respectively. The stiffness of the right and left upper trapezius muscles and right and left pectoralis minor muscles were 42.5 ± 14.1, 47.1 ± 17.1, 20.5 ± 8.0 and 17.9 ± 8.4, respectively. In multiple regression analysis, it was observed that the stiffness of the left upper trapezius muscle was positively correlated with the shoulder angle.

CONCLUSION

The upper trapezius muscle stiffness increased in RSP. It can reveal the relationship between RSP and neck pain.

Ultrasound shear wave elastography measurement of the deep posterior cervical muscles: Reliability and ability to differentiate between muscle contraction states

The deep posterior cervical muscles (DPCM), specifically the semispinalis cervicis and cervical multifidus, are often impaired in patients with neck disorders and have been assessed by several imaging techniques. Prior ultrasound shear wave elastography (SWE) imaging and reliability assessments of the DPCM were performed utilizing similar positioning as assessments for the more superficial cervical extensors. Our objectives were to describe an SWE imaging technique for the DPCM, establish intra-rater reliability of DPCM SWE, and compare DPCM shear modulus during rest and submaximal contraction in both prone and seated positions in individuals without spinal pain. In sixteen participants, the DPCM was located using B-mode ultrasound, then muscle shear modulus was assessed via SWE at both rest and with contraction against a 2-kg resistance applied at the C2 spinous process. Within-day intra-rater reliability was moderate to good (ICC = 0.70-0.88). The DPCM were stiffer during contraction than at rest in the prone position (p = 0.002), and at rest in sitting versus at rest in prone (p = 0.003). Further research is needed to assess DPCM-specific SWE in symptomatic individuals and compare DPCM shear modulus to electromyography across contraction intensities.