Posture-related stiffness mapping of paraspinal muscles

The Immediate Effect of a Single Treatment of Neuromuscular Electrical Stimulation with the StimaWELL 120MTRS System on Multifidus Stiffness in Patients with Chronic Low Back Pain

BACKGROUND/OBJECTIVES

Individuals with chronic low back pain (CLBP) have altered lumbar multifidus stiffness properties compared to healthy controls. Although neuromuscular electrical stimulation (NMES) application to the multifidus might affect stiffness, this has never been investigated. The aims of this study were to examine the effect of a single NMES treatment on multifidus stiffness and pain intensity in CLBP patients.

METHODS

30 participants (13 male, 17 female) were randomized to one of two intervention ('phasic' and 'combined') protocols with the StimaWELL 120MTRS system. Multifidus stiffness at L4 and L5 was measured via shear-wave elastography (SWE) at rest and in standing prior to, and 15 min after, a 20 min NMES treatment. Pain intensity was measured pre- and post-treatment with the numerical pain rating scale (NPRS).

RESULTS

There were significant increases in resting shear modulus at right L4 (p = 0.001) and bilaterally at L5 (p = 0.017; p = 0.020) in the 'combined' intervention group, and a significant between-group difference at right L4 (p < 0.001). There were significant decreases in standing shear modulus at right L4 (p = 0.015) and left L5 (p = 0.036) in the 'combined' intervention group, and a significant between-group difference at left L5 (p = 0.016). Both groups experienced significant decreases in pain intensity (MD combined group = 1.12, 95% CI [0.34, 1.90], p = 0.011) (MD phasic group = 1.42, 95% CI [0.68, 2.16], p = 0.001).

CONCLUSIONS

There were multiple significant changes in multifidus stiffness in the combined group, but not in the phasic group. Both groups experienced significant decreases in low back pain intensity.

Evaluation of the Reproducibility of MR Elastography Measurements of the Lumbar Back Muscles

BACKGROUND

MR elastography (MRE) may provide quantitative imaging biomarkers of lumbar back muscles (LBMs), complementing MRI in spinal diseases by assessing muscle mechanical properties. However, reproducibility analyses for MRE of LBM are lacking.

PURPOSE

To assess technical failure, within-day and inter-day reproducibility, robustness with the excitation source positioning, and inter-observer agreement of MRE of muscles.

STUDY TYPE

Prospective.

SUBJECTS

Seventeen healthy subjects (mean age 28 ± 4 years; 11 females).

FIELD STRENGTH/SEQUENCE

1.5 T, gradient-echo MRE, T1-weighted turbo spin echo.

ASSESSMENT

The pneumatic driver was centered at L3 level. Four MRE were performed during two visits, 2-4 weeks apart, each consisting of two MRE with less than 10 minutes inter-scan interval. At Visit 1, after the first MRE, the coil and driver were removed, then reinstalled. The MRE was repeated. At Visit 2, following the first MRE, only the driver was moved down 5 cm. The MRE was repeated. Two radiologists segmented the multifidus and erector spinae muscles.

STATISTICAL TESTS

Paired t-test, analysis of variance, intraclass correlation coefficients (ICCs). P-values <0.05 were considered statistically significant.

RESULTS

Mean stiffness of LBM ranged from 1.44 to 1.60 kPa. Mean technical failure rate was 2.5%. Inter-observer agreement was excellent (ICC ranging from 0.82 [0.64-0.96] to 0.99 [0.98-0.99] in the multifidus, and from 0.85 [0.69-0.92] to 0.99 [0.97-0.99] in the erector spinae muscles). Within-day reproducibility was fair in the multifidus (ICC: 0.53 [0.47-0.77]) and good in the erector spinae muscles (ICC: 0.74 [0.48-0.88]). Reproducibility after moving the driver was excellent in both multifidus (ICC: 0.85 [0.69-0.93]) and erector spinae muscles (ICC: 0.84 [0.67-0.92]). Inter-day reproducibility was excellent in the multifidus (ICC: 0.76 [0.48-0.89]) and poor in the erector spinae muscles (ICC: 0.23 [-0.61 to 0.63]).

DATA CONCLUSION

MRE of LBM provides measurements of stiffness with fair to excellent reproducibility and excellent inter-observer agreement. However, inter-day reproducibility in the multifidus muscles indicated that the herein used MRE protocol may not be optimal for this muscle.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY: Stage 1.

Paraspinal Muscle Stiffness during Hamstring Exercise Using Shear-Wave Elastography

Soccer teams integrate specific exercises into their typical workout programs for injury prevention. This study examined the effects of hamstring exercise on paraspinal and hamstring stiffness. These findings can inform training and rehabilitation programs to improve muscle health and prevent injuries. Fifteen young, healthy males performed passive and active (submaximal) knee flexion efforts from 0°, 45°, to 90° angle of knee flexion from the prone position. Using shear-wave elastography (SWE) and surface electromyography, we measured the elastic modulus and root mean square (RMS) signal of the erector spinae (ES), multifidus (MF), semitendinosus (ST), and semimembranosus (SM) during different knee flexion angles. Passive SWE modulus at 0° was 12.44 ± 4.45 kPa (ES), 13.35 ± 6.12 kPa (MF), 22.01 ± 4.68 kPa (ST), and 21.57 ± 5.22 kPa (SM) and it was greater (p < 0.05) compared to 45° and 90°. The corresponding values during knee flexion contractions at 0° increased to 18.99 ± 6.11 kPa (ES), 20.65 ± 11.31 kPa (MF), 71.21 ± 13.88 kPa (ST), and 70.20 ± 14.29 kPa (SM) and did not differ between angles (p > 0.05). Compared to rest, the relative increase in the SWE modulus during active contraction had a median value (interquartile range) ranging from 68.11 (86.29) to 101.69 (54.33)% for the paraspinal muscles and it was moderately to strongly correlated (r > 0.672) with the corresponding increase of the hamstring muscles [ranging from 225.94 (114.72) to 463.16 (185.16)%]. The RMS signal was greater during active compared to passive conditions, and it was lower at 90° compared to 45° (for SM/ST) and 0° (for all muscles). The association between paraspinal and hamstring passive muscle stiffness indicates a potential transmission of forces through myofascial connections between the lumbar spine and the lower limbs. In this laboratory setting, hamstring exercises affected the stiffness of the paraspinal muscles.

Comparison of elasticity changes in the paraspinal muscles of adolescent patients with scoliosis treated with surgery and bracing

Scoliosis is a three-dimensional spinal deformity, and paraspinal muscles play an important role as stabilizers of the spinal curve. In this prospective study, we compared elasticity changes in the paraspinal muscles of adolescent patients with scoliosis after surgery or bracing. Elasticity was measured on the concave and convex sides of the paraspinal muscles at the apex of the curve at the beginning of treatment and 6 and 12 months after treatment. Twenty-six patients with correction surgery (n = 15) or bracing (n = 11) were included. At initial evaluation, the Cobb angle was larger in the surgery group (72.3 ± 20.2° in surgery vs. 30.6 ± 5.1° in brace, p < 0.001). The estimated mean elasticity value of the paraspinal muscles was lower in the surgery group at baseline on the convex side (15.8 vs. 22.8 kPa, p = 0.037) and 6 months on both the concave (12.1 vs. 22.7 kPa, p = 0.004) and convex (13.4 vs. 23.8 kPa, p = 0.005) sides. There was a significant stiffness decrease from baseline to 6 months on the concave side in the surgery group (5.9 kPa, p = 0.025). However, the elasticity change recovered at 12 months without significant differences between the two groups.

Comparison of the activation and mechanical properties of scapulothoracic muscles in young tennis players with and without scapular dyskinesis: an observational comparative study

BACKGROUND

In tennis athletes with scapular dyskinesis, the activation of the scapulothoracic muscles during serve is not known. Also, the mechanical properties (tone, elasticity, and stiffness) of the scapulothoracic muscles of the tennis athletes with scapular dyskinesis are likely to change. The study aimed to evaluate the activation of the scapulothoracic muscles while performing tennis serve and to determine the changes in the mechanical properties of the same muscles in young tennis athletes with scapular dyskinesis.

METHODS

Seventeen tennis athletes with scapular dyskinesis aged between 11 and 18 years (the scapular dyskinesis group) and age- and gender-matched 17 asymptomatic tennis athletes (the control group) were included in the study. Activation of scapulothoracic muscles (descending-transverse-ascending trapezius and serratus anterior) in the 3 phases (preparation, acceleration, and follow-through) of the serve was evaluated using surface electromyography, and the mechanical properties of the same muscles were measured at rest by myotonometry.

RESULTS

Ascending trapezius activation in the follow-through phase was lower in the scapular dyskinesis group compared with the control group (mean difference 95% confidence interval: -22.8 [-41.2 to -4.5]) (P = .017). The tone and stiffness of the transverse trapezius (P = .043 and P = .017, respectively) were higher, whereas the same parameters of the ascending trapezius were lower (P = .008 and P = .010, respectively) in the scapular dyskinesis group compared with the control group.

CONCLUSIONS

Activation of the ascending trapezius and the tone and stiffness of the transverse-ascending trapezius were altered in tennis athletes with scapular dyskinesis. Implementations to improve these changes can be included in the rehabilitation or training programs of young tennis athletes with scapular dyskinesis.

Reliability of shear-wave elastography in assessing the stiffness of the nuchal fascia and the thickness of upper cervical muscles

OBJECTIVE

To determine the reliability of shear-wave elastography (SWE)in assessing the stiffness of the nuchal fascia and the thickness of upper cervical muscles in neutral head posture (NHP) or forward head posture (FHP).

METHODS

Sixteen healthy adults (mean age: 21.69 ± 1.01years, 9 females) were included. SWE mode was chosen to measure the nuchal fascia shear modulus and muscle thickness was measured in B-mode. Measurements were collected by two independent investigators on two different days. The intraclass correlation coefficient (ICC) was used to measure the relative reliability, and the standard error of measurement (SEM) were used to measure the absolute reliability.

RESULTS

Intra‑rater (ICC = 0.63-0.89) and inter-rater (ICC = 00.54-0.82) reliability for the nuchal fascia shear modulus were moderate to excellent. Intra‑rater (ICC = 00.64-0.96) and inter-rater (ICC = 00.48-0.86) reliability for upper cervical muscles thickness were moderate to excellent. The SEM percentage oscillated from 3.27% to 13.55%. There were significant differences(P < 0.05) between NHP and FHP on nuchal fascia shear modulus, right side splenius capitis muscle thickness and left side semispinalis capitis muscle thickness, but no significant differences(P > 0.05) were observed between the right and left sides. The upper cervical muscles thickness of males was significantly thicker(P < 0.01) than females while no significant differences were observed (P > 0.05) on the nuchal fascia shear modulus.

CONCLUSIONS

Ultrasound-based SWE may be a reliable tool for assessing the stiffness of the nuchal fascia and the thickness of upper cervical muscles in clinical practice.

REGISTRATION NUMBER

ChiCTR2200055736.

Shear Wave Elastography in Patients with Spinal Muscular Atrophy Types 2 and 3

INTRODUCTION

 This study aimed to investigate selective muscle involvement by shear wave elastography (SWE) in patients with spinal muscular atrophy (SMA) types 2 and 3 and to compare SWE values with magnetic resonance imaging (MRI) in demonstrating muscle involvement.

METHODS

 Seventeen patients with SMA types 2 and3 were included in the study. SWE was used to evaluate stiffness of the upper and lower extremities and paraspinal muscles. Involvement of the paraspinal muscles was evaluated using 1.5-T MRI.

RESULTS

 Among the upper extremity muscles, SWE values were the highest for the triceps brachii; however, no significant difference was noted (p = 0.23). In post hoc analysis, a significant difference was observed between triceps brachii and biceps brachii (p = 0.003). Patients with a longer disease duration have the highest SWE values for the triceps brachii (r = 0.67, p = 0.003). Among the lower extremity muscles, SWE values for the iliopsoas were significantly higher than the gluteus maximus (p < 0.001). A positive correlation was found between SWE values and MRI scores of paraspinal muscles (r = 0.49, p = 0.045; r = 0.67, p = 0.003).

CONCLUSION

 This is the first study to report muscle involvement assessed by SWE in patients with SMA types 2 and 3. Our findings are similar to the presence of selective muscle involvement demonstrated in previous studies, and also SWE and MRI values were similar. SWE is an alternative noninvasive practical method that can be used to demonstrate muscle involvement in patients with SMA, to understand the pathogenesis of segmental involvement, and to guide future treatments or to monitor the effectiveness of existing new treatment options.

Effect of trunk exercise upon lumbar IVD height and vertebral compliance when performed supine with 1 g at the CoM compared to upright in 1 g

Background

Spinal unloading in microgravity is associated with stature increments, back pain, intervertebral disc (IVD) swelling and impaired spinal kinematics. The aim of this study was to determine the effect of lateral stabilization, trunk rotation and isometric abdominal exercise upon lumbar IVD height, and both passive and active vertebral compliance when performed supine on a short-arm human centrifuge (SAHC)—a candidate microgravity countermeasure—with 1 g at the CoM, compared to that generated with equivalent upright exercise in 1 g.

Methods

12 (8 male) healthy subjects (33.8 ± 7 years, 178.4 ± 8.2 cm, 72.1 ± 9.6 kg) gave written informed consent. Subjects performed three sets of upper body trunk exercises either when standing upright (UPRIGHT), or when being spun on the SAHC. Lumbar IVD height and vertebral compliance (active and passive) were evaluated prior to SAHC (PRE SAHC) and following the first SAHC (POST SPIN 1) and second Spin (POST SPIN 2), in addition to before (PRE UPRIGHT), and after upright trunk exercises (POST UPRIGHT).

Results

No significant effect upon IVD height (L2–S1) when performed UPRIGHT or on the SAHC was observed. Trunk muscle exercise induced significant (p < 0.05) reduction of active thoracic vertebral compliance when performed on the SAHC, but not UPRIGHT. However, no effect was observed in the cervical, lumbar or across the entire vertebral column. On passive or active vertebral compliance.

Conclusion

This study, the first of its kind demonstrates that trunk exercise were feasible and tolerable. Whilst trunk muscle exercise appears to have minor effect upon IVD height, it may be a candidate approach to mitigate—particularly active—vertebral stability on Earth, and in μg via concurrent SAHC. However, significant variability suggests larger studies including optimization of trunk exercise and SAHC prescription with MRI are warranted.

Trial Registration

North Rhine ethical committee (Number: 6000223393) and registered on 29/09/2020 in the German Clinical Trials Register (DRKS00021750).

Influence of Spinal Movements Associated with Physical Evaluation on Muscle Mechanical Properties of the Lumbar Paraspinal in Subjects with Acute Low Back Pain

This research aimed to identify changes in muscle mechanical properties (MMPs) when a standardized sequence of movements is performed and to determine the influence of acute low back pain (LBP) and age on the MMPs. Socio-demographic, clinical variables and MMPs were collected in 33 patients with LBP and 33 healthy controls. A 2 × 2 × 2 (group × age × time) analysis of variance (ANOVA) mixed model was used to determine the effect of the study factors on the different MMPs. There were no significant triple interactions. After the movements, tone and stiffness increased 0.37 Hz and 22.75 N/m, respectively, in subjects <35 years, independent of their clinical status. Relaxation showed differences by age in healthy subjects and creep in LBP subjects. Furthermore, elasticity was higher in <35 years (p < 0.001) without the influence of any other factor. In conclusion, sequenced movements can modify tone and stiffness as a function of age, while age-associated changes in viscoelastic characteristics depends on pain but not on movements. The MMPs should be assessed, not only at the beginning of the physical examination at rest, but also along the patient's follow-up, depending on their pain and age, in a clinical setting.

Straighten your back! Self-correction posture and postural balance in "non rehabilitative instructed" multiple sclerosis patients

BACKGROUD

Patients with MS, regardless of the complexity of the activity or sensory conditions, commonly present a significant postural control deficit compared to healthy subjects.

OBJECTIVE

To investigate which postural self-correction strategies are adopted by patients with Multiple Sclerosis versus a group of healthy-subjects and how self-correction can influence the control of postural balance.

METHODS

A case-control prospective observational study was conducted. Person with Multiple Sclerosis and a group of healthy volunteers were enrolled. Patients included were instructed with vocal commands, to reach a self-correction posture, and they were compared to healthy subjects. Clinical assessments including Balance, Stabilometry and Postural evaluation of the spine were performed.

RESULTS

Sixty patients (30: control-group; 30: treatment-group) were enrolled. In the treatment group, the analysis reported a significant statistical difference between path length and center of pressure speed in self-correction posture with closed-eyes (p = 0,049; 0,047) and an improvement in C7 and L3 levels in self-correction posture (p < 0,01-C7; p < 0,01-L3). There are significant statistical differences about path length between the two groups in all examined conditions (p = 0,0001). At sagittal plane evaluation, results show an increase of all measurements in both posture (C7-neutral posture p = 0,0001; L3-neutral posture p = 0,0001; C7-self-correction posture p = 0,0001; L3-self-correction posture p = 0,0001).

CONCLUSION

Further study should investigate dynamic situations and different Multiple Sclerosis forms to complete balance analysis and to establish a correct rehabilitative program with self-correction exercise as powerful focus.

Inconsistent descriptions of lumbar multifidus morphology: A scoping review

BACKGROUND

Lumbar multifidus (LM) is regarded as the major stabilizing muscle of the spine. The effects of exercise therapy in low back pain (LBP) are attributed to this muscle. A current literature review is warranted, however, given the complexity of LM morphology and the inconsistency of anatomical descriptions in the literature.

METHODS

Scoping review of studies on LM morphology including major anatomy atlases. All relevant studies were searched in PubMed (Medline) and EMBASE until June 2019. Anatomy atlases were retrieved from multiple university libraries and online. All studies and atlases were screened for the following LM parameters: location, imaging methods, spine levels, muscle trajectory, muscle thickness, cross-sectional area, and diameter. The quality of the studies and atlases was also assessed using a five-item evaluation system.

RESULTS

In all, 303 studies and 19 anatomy atlases were included in this review. In most studies, LM morphology was determined by MRI, ultrasound imaging, or drawings - particularly for levels L4-S1. In 153 studies, LM is described as a superficial muscle only, in 72 studies as a deep muscle only, and in 35 studies as both superficial and deep. Anatomy atlases predominantly depict LM as a deep muscle covered by the erector spinae and thoracolumbar fascia. About 42% of the studies had high quality scores, with 39% having moderate scores and 19% having low scores. The quality of figures in anatomy atlases was ranked as high in one atlas, moderate in 15 atlases, and low in 3 atlases.

DISCUSSION

Anatomical studies of LM exhibit inconsistent findings, describing its location as superficial (50%), deep (25%), or both (12%). This is in sharp contrast to anatomy atlases, which depict LM predominantly as deep muscle. Within the limitations of the self-developed quality-assessment tool, high-quality scores were identified in a majority of studies (42%), but in only one anatomy atlas.

CONCLUSIONS

We identified a lack of standardization in the depiction and description of LM morphology. This could affect the precise understanding of its role in background and therapy in LBP patients. Standardization of research methodology on LM morphology is recommended. Anatomy atlases should be updated on LM morphology.