Are lumbar multifidus fatigue and transversus abdominis activation similar in patients with lumbar disc herniation and healthy controls? A case control study

The Application of Surface Electromyography Technology in Evaluating Paraspinal Muscle Function

Surface electromyography (sEMG) has emerged as a valuable tool for assessing muscle activity in various clinical and research settings. This review focuses on the application of sEMG specifically in the context of paraspinal muscles. The paraspinal muscles play a critical role in providing stability and facilitating movement of the spine. Dysfunctions or alterations in paraspinal muscle activity can lead to various musculoskeletal disorders and spinal pathologies. Therefore, understanding and quantifying paraspinal muscle activity is crucial for accurate diagnosis, treatment planning, and monitoring therapeutic interventions. This review discusses the clinical applications of sEMG in paraspinal muscles, including the assessment of low back pain, spinal disorders, and rehabilitation interventions. It explores how sEMG can aid in diagnosing the potential causes of low back pain and monitoring the effectiveness of physical therapy, spinal manipulative therapy, and exercise protocols. It also discusses emerging technologies and advancements in sEMG techniques that aim to enhance the accuracy and reliability of paraspinal muscle assessment. In summary, the application of sEMG in paraspinal muscles provides valuable insights into muscle function, dysfunction, and therapeutic interventions. By examining the literature on sEMG in paraspinal muscles, this review offers a comprehensive understanding of the current state of research, identifies knowledge gaps, and suggests future directions for optimizing the use of sEMG in assessing paraspinal muscle activity.

Paravertebral Muscular Neurophysiological Function as an Independent Outcome Predictor of Recurring Herniation/Low Back Pain after Radiofrequency Ablation: A Prospective Follow-Up and Case-Control Study Based on Surface Electromyography

OBJECTIVE

Spinal endoscopy radiofrequency is a minimally invasive technique for lumbar disc herniation (LDH) and low back pain (LBP). However, recurring LDH/LBP following spinal endoscopy radiofrequency is a significant problem. Paravertebral musculature plays a crucial role in spine stability and motor function, and the purpose of the present study was to identify whether patients' baseline lumbar muscular electrophysiological function could be a predictor of recurring LDH/LBP.

METHODS

This was a prospective follow-up and case-control study focusing on elderly patients with LDH who were treated in our department between January 1, 2018, and October 31, 2021. The end of follow-up was recurring LBP, recurring LDH, death, missing to follow-up or 2 years postoperation. The surface electromyography test was performed before the endoscopy C-arm radiofrequency (ECRF) operation to detect the flexion-relaxation ratio (FRR) of the lumbar multifidus (FRRLM ) and the longissimus erector spinae (FRRES ), and the other baseline parameters included the general characteristics, the visual analogue scale, the Japanese Orthopaedic Association score, and the Oswestry Disability Index. Intergroup comparisons were performed by independent t-test and χ2 -test, and further binary logistic regression analysis was performed.

RESULTS

Fifty-four patients completed the 2-year follow-up and were retrospectively divided into a recurring LDH/LBP group (Group R) (n = 21) and a no recurring group (Group N) (n = 33) according to their clinical outcomes. FRRLM and FRRES in Group N were much higher than those in Group R (p < 0.001, p = 0.009). Logistic regression analysis showed that only the FRRLM (odds ratio [OR] = 0.123, p = 0.011) and FRRES (OR = 0.115, p = 0.036) were independent factors associated with the ECRF outcome.

CONCLUSIONS

Lumbar disc herniation patients' baseline FRRLM and FRRES are independent outcome predictors of recurring LDH/LBP after ECRF. For every unit increase in baseline FRRLM , the risk of recurring LDH/LBP is decreased by 87.7%, and for every unit increase in baseline FRRES , the risk of recurring LDH/LBP is decreased by 88.5%.

A diagnostic model of nerve root compression localization in lower lumbar disc herniation based on random forest algorithm and surface electromyography

Objective

This study aimed to investigate the muscle activation of patients with lumbar disc herniation (LDH) during walking by surface electromyography (SEMG) and establish a diagnostic model based on SEMG parameters using random forest (RF) algorithm for localization diagnosis of compressed nerve root in LDH patients.

Methods

Fifty-eight patients with LDH and thirty healthy subjects were recruited. The SEMG of tibialis anterior (TA) and lateral gastrocnemius (LG) were collected bilaterally during walking. The peak root mean square (RMS-peak), RMS-peak time, mean power frequency (MPF), and median frequency (MF) were analyzed. A diagnostic model based on SEMG parameters using RF algorithm was established to locate compressed nerve root, and repeated reservation experiments were conducted for verification. The study evaluated the diagnostic efficiency of the model using accuracy, precision, recall rate, F1-score, Kappa value, and area under the receiver operating characteristic (ROC) curve.

Results

The results showed that delayed activation of TA and decreased activation of LG were observed in the L5 group, while decreased activation of LG and earlier activation of LG were observed in the S1 group. The RF model based on eight SEMG parameters showed an average accuracy of 84%, with an area under the ROC curve of 0.93. The RMS peak time of TA was identified as the most important SEMG parameter.

Conclusion

These findings suggest that the RF model can assist in the localization diagnosis of compressed nerve roots in LDH patients, and the SEMG parameters can provide further references for optimizing the diagnosis model in the future.

Immediate effect of trunk flexion and extension isometric exercise using an external compression device on electromyography of the hip extensor and trunk range of motion of healthy subjects

Background

Sacroiliac joints (SIJs) transmitted trunk load to lower extremities through the lumbopelvis. External compression devices across the SIJs could provide stability to the SIJs. A previous study established that using a device known as Active Therapeutic Movement version 2 (ATM^®2) has been developed to improve pain and joint range of motion (ROM) in patients with LBP. However, no study has examined the physiological change in the muscle through ATM®2-based exercise thus far. This study aimed to determine the immediate effects of ATM^®2 exercise on the contraction timing, back extension endurance, muscle fatigue, and trunk ROM of lumbar and lower limb muscles in healthy subjects.

Methods

Thirty-six healthy subjects (mean age = 23.16 ± 2.3) volunteered to participate in this study. Subjects were instructed to perform ROM test using sit and reach test, back extensor endurance test using Biering-Sorensen test, erector spinae (ES), lumbar multifidus (LM) fatigue and onset time of Gluteus maximus (GM) in prone hip extension using electromyography before and after trunk flexion and extension isometric exercises.

Results

The ROM in trunk flexion showed a significant increase of 7.9% after exercise compared to that before exercise (p < 0.05). Relative GM contraction onset timing significantly decreased after exercise (p < 0.05). The result of the Sorensen test after exercise showed a trend of increase in duration time. Muscle fatigue in the LM, however, showed a significant increase (p < 0.05), whereas muscle fatigue in the ES was reduced without statistical significance.

Conclusions

The results base on this study showed that exercise-based on ATM®2 is an effective exercise protocol with an effect on the biomechanics of healthy subjects.

Clinical trial registration numbers KCT0006728. Clinical trial registration date: 09/11/2021.

Non randomised trial of GRAVITY system therapy effectiveness in chronic, low intensity low back disc disease

Study aim: Chronic low back pain (CLBP) is a therapeutically challenging pain syndrome. Physical exercises are the most common therapy used in CLBP treatment. The aim of the study was to verify if GRAVITY system exercise can be effective in the therapy of chronic discogenic low back pain. The GRAVITY system exercise aims at strengthening full body muscles using the trainee’s own body weight only.

Material and methods: The study was registered at ClinicalTrials.gov Identifier: NCT04765293. We used TREND statement. The study populations were 50 patients with CLBP. The study population (group I) consisted of 25 patients who had GRAVITY system exercise. The clinical control group were 25 patients who received standard treatment in an outpatient clinic of National Health Fund. Before the start of the training, the patients’ had their muscle strength responsible for stabilizing the lumbar segment measured. We also measured patients’ Oswestry Disability Index (ODI) prior to and after the therapy cycle. The therapy was conducted twice a week for 40 minutes over the period of 4 weeks. The clinical control group were 25 patients who received treatment from the National Health Fund and had only standardised physical therapy (laser, ultrasound, cryotherapy and magnetic therapy) sessions for two weeks.

Results. We found statistically significant reduction in pain and disability in the study population after the treatment, but muscle strength did not increase significantly.

Conclusions: 1. GRAVITY system exercise might efficient in pain and disability reduction. Muscle strength did not increase after therapy. 2. Pain and disability had positive correlation with female sex, decreased physical activity and sedentary work.

Reliability of lumbar multifidus ultrasound assessment during the active straight leg raise test

BACKGROUND

Previous evidence showed altered lumbar multifidus (LM) activation in populations with chronic nonspecific low back pain (LBP). We aimed to investigate the test-retest and inter-examiner reliability of ultrasound imaging (US) for assessing LM thickness at rest and activation during the active straight leg raise test (ASLR) and the association between thickness changes with clinical outcomes.

METHODS

Fifty-two patients with LBP and two examiners (one experienced and one novice) participated in this study. A total of 18 B-mode images at L4-L5 or L5-S1 level (both sides, 3 at rest and 6 during ASLR) were collected. For assessing test-retest reliability, the experienced examiner repeated the procedure after 7 days. Intraclass correlation coefficients (ICC), standard error of measurements (SEM) and minimal detectable changes (MDC) were calculated.

RESULTS

Inter-examiner agreement was good to excellent (ICC3,2 = 0.71-0.92) and test-retest reliability was excellent (ICC3,1 = 0.91-0.98). Mean average of multiple measurements improved the agreement. Greater LM thickness at rest (p < .05) and greater thickness change after 3 s (p < .01) and 10 s (homolateral side, p < .01; contralateral side, p < .05) were associated with less pain intensity.

CONCLUSIONS

US is a reliable method to assess the LM thickness at rest and contracted during the ASLR in patients with LBP. The measurement at 3 s after maintaining ASLR, as well as the use of the mean of three measurements, has been shown to be the most reliable method for measuring LM muscle thickness during ASLR.

Multifidus Muscle Fiber Type Distribution is Changed in Mouse Models of Chronic Intervertebral Disc Degeneration, but is not Attenuated by Whole Body Physical Activity

STUDY DESIGN

Case-controlled animal study.

OBJECTIVE

The aim of this study was to investigate whether multifidus muscle fiber type distribution changes in models of interverbal disc (IVD) degeneration and whether this is resolved by physical activity (PA).

SUMMARY OF BACKGROUND DATA

The loss of slow type I muscle fibers in the multifidus muscle in people with low back pain is contentious. Data from animal models of IVD degeneration suggest some discrepancies in human studies might be explained by the dependence of slow muscle fiber changes and their underlying mechanisms, on the time since injury and progression of IVD degeneration. It is not yet resolved what changes are apparent once the chronic phase is established. It is also not known whether muscle fiber changes can be resolved by whole body PA. This study aimed to examine slow fiber distribution in the multifidus muscle in models of IVD injury or spontaneous degeneration in animals with or without exposure to PA.

METHODS

Two models of IVD degeneration were used. The first model used a genetically modified mouse (SPARC-null) that spontaneously develops IVD degeneration. The second model involved a surgically induced IVD lesion to induce degeneration. Mice in each study were allocated to housing with or without a running wheel for PA. At 12 months of age, the multifidus muscle was harvested. Slow muscle fiber distribution and the mRNA expression of genes associated with muscle fiber type transformation were examined.

RESULTS

The proportion and cross-sectional area of slow muscle fibers were reduced in both models of IVD degeneration compared to controls, without evidence of ongoing fiber transformation. Whole-body PA did not attenuate these alterations.

CONCLUSION

Results confirmed slow muscle fiber loss in the multifidus in the chronic phase of IVD degeneration induced spontaneously and by injury. Whole-body PA did not attenuate changes to muscle fiber distribution. More specific approaches to muscle activation might be required to achieve more complete reversal of muscle fiber changes, with potential implications for therapy in humans.Level of Evidence: N/A.

The influence of Kinesio Taping on muscle fatigue in individuals with low back pain: A randomised controlled trial

OBJECTIVE

To evaluate the effect of different taping techniques on back muscle fatigue in people with low back pain.

METHODS

Sixty women with chronic non-specific low back pain were randomly assigned to four groups of 15 participants each: control (CG), Kinesio Taping (KT) with tension (KTT), KT no tension (KTNT) and Micropore® (MP), which were applied over the erector spinae muscles. The median frequency (MF) fatigue slopes of the longissimus muscle and sustained contraction time during a trunk fatigue test (Ito test), and pain using the numerical pain rating scale (NPRS) were collected at three time points: pre-treatment, three and ten days after intervention at a university laboratory.

RESULTS

Significant differences were seen in the MF slopes between groups (p= 0.01, η2= 0.20), with the KTT showing a mean difference (MD = 0.31, p= 0.04) and KTNT (MD = 0.28, p= 0.04) compared with CG. Significant reductions in NPRS were seen between time points (p< 0.001, η2= 0.28), with a reduction between pre and 3 days (MD = 1.87, p< 0.001), and pre and 10 days (MD = 1.38, p< 0.001), with KTT and KTNT both showing clinically important changes.

CONCLUSION

KT, with or without tension, has a tendency to reduce back muscle fatigue and reduce pain in individuals with chronic non-specific low back pain.

Cortical Representations of Transversus Abdominis and Multifidus Muscles Were Discrete in Patients with Chronic Low Back Pain: Evidence Elicited by TMS

Introduction

The transversus abdominis (TVA) and multifidus (MF) muscles are the main segmental spinal stabilizers that are controlled by the primary motor cortex of the brain. However, relocations of the muscle representation in the motor cortex may occur after chronic lower back pain (cLBP); it still needs more evidence to be proven. The current study was aimed at applying transcranial magnetic stimulation (TMS) to investigate the changes of representation of TVA and MF muscles at the cortical network in individuals with cLBP.

Methods

Twenty-four patients with cLBP and 12 age-matched healthy individuals were recruited. Responses of TVA and MF to TMS during muscle contraction were monitored and mapped over the contralateral cortex using a standardized grid cap. Maps of the center of gravity (CoG), area, volume, and latency were analyzed, and the asymmetry index was also computed and compared.

Results

The locations of MF CoG in cLBP individuals were posterior and lateral to the CoG locations in healthy individuals. In the healthy group, the locations of TVA and MF CoG were closed to each other in both the left and right hemispheres. In the cLBP group, these two locations were next to each other in the right hemisphere but discrete in the left hemisphere. In the cLBP group, the cortical motor map of TVA and MF were mutually symmetric in five out of eleven (45.5%) subjects and leftward asymmetric in four out of ten (40.0%) subjects.

Conclusions

Neural representations of TVA and MF muscles were closely organized in both the right and left motor cortices in the healthy group but were discretely organized in the left motor cortex in the cLBP group. This provides strong support for the neural basis of pathokinesiology and clinical treatment of cLBP.

Electromyography activities in patients with lower lumbar disc herniation

BACKGROUND

Lumbar disc herniation (LDH) can affect lower limb muscle function resulting in an abnormal gait. This study aims to use surface electromyography (SEMG) to evaluate patients with L4/L5 and L5/S1 LDH throughout muscle movement.

METHODS

Twenty L4/L5 LDH patients (L5 Group), twenty L5/S1 LDH patients (S1 Group), and twenty healthy controls (Healthy) were recruited for the study. SEMG of bilateral tibialis anterior (TA) and lateral gastrocnemius (LG) muscles of patients were recorded using the DELSYS Wireless EMG System (TrignoTM Wireless Systems, Delsys Inc., USA). Root-mean-square (RMS), mean power frequency (MPF), and median frequency (MF) were compared between bilateral limbs in each participant.

RESULTS

Reduced MPF and MF was found in TA measurements of the L5 Group and LG measurements of the S1 Group. The MPF and MF of the TA of symptomatic limbs of the L5 Group were reduced when compared to asymptomatic limbs (p= 0.006, p= 0.012, p< 0.05), and there were no significant differences in LG measurements (p> 0.05). The LG MPF and MF of the S1 Group in symptomatic limbs were reduced when compared to asymptomatic limbs (p= 0.006, p= 0.017, p< 0.05), and there were no significant differences in TA measurements (p> 0.05). Although there were no significant differences in RMS between bilateral limbs of the L5 and S1 Groups, we found some changes in RMS curves. First, compared to asymptomatic limbs of L4/L5LDH patients, β-peaks in the TA of symptomatic limbs appeared earlier. Second, two peaks in the LG of symptomatic limbs were found in L5/S1 LDH patients.

CONCLUSION

TA is affected in patients with LDH of L4/L5, and LG is affected in patients with LDH of L5/S1. As demonstrated, SEMG can identify LDH-related muscle dysfunction.

Comparing the effects of aquatic exercises with or without high intensity on the functional status, muscular endurance, and performance of patients with chronic low back pain

BACKGROUND

The prevalence of low back pain is lower when physical fitness (aerobic and muscular) is higher. Strength exercises are important for subjects with low back pain, but there are few studies on the inclusion of aerobic exercise in low back pain programs. The aim of this study was to compare the effects of aquatic exercises with or without high-intensity component on the functional status, lumbar and abdominal muscle endurance, and performance of subjects with chronic low back pain.

METHODS

Forty-eight volunteers between 20 and 60 years old were randomly allocated to an experimental group AEDWR (aquatic exercises plus deep-water running group, N.=25) or to a control group AE (aquatic exercises only group, N.=23). The dependent variables included functional status (Repeated Sit-to-Stand test), lumbar (Sorensen test) and abdominal (One Minute Abdominal test) muscle endurance, and physical performance (Maximum Physical Fitness test), which were measured before and after the 9-week intervention and at 21 weeks of follow-up.

RESULTS

Lumbar endurance was higher in the AEDWR group at the end of the treatment, with a mean difference (MD) of 43.2 seconds, 95% confidence intervals (CI) (9.6; 76.7), P=0.01, d̅=0.74, and better in the follow-up with MD=40.2 seconds, 95% CI (7.1; 73.3), P=0.02, d̅=0.71, than in the AE group. Participant performance also improved on the 9^th week in the AEDWR group, with an MD=0.53 kgf, 95% CI (0.008; 0.98), P=0.02, d̅=0.60.

CONCLUSIONS

The addition of deep-water running exercise to aquatic exercises improved lumbar muscle endurance and performance when compared with aquatic exercises only, and this effect was maintained during the follow-up to lumbar muscle endurance.

Trunk muscle activity during pressure feedback monitoring among individuals with and without chronic low Back pain

BACKGROUND

Pressure biofeedback unit (PBU) is a widely used non-invasive device to assist core muscle training by providing pressure feedback. The aim this study was to compare the muscle activities of transverse abdominis (TA) and multifidus (MF) at different target pressures (50, 60 and 70 mmHg) of PBU between individuals with and without cLBP.

METHODS

Twenty-two patients with chronic LBP (cLBP) and 24 age matched healthy individuals were recruited. Electromyography (EMG) signals were recorded from the TA and MF muscles while the TA and MF were contracted to achieve PBU pressure value of 50, 60 and 70 mmHg in random order. The average EMG amplitude (AEMG) of 3 replicate trials was used in the analysis after normalization to %MVIC. %MVIC is defined as the mean of the three AEMG divided by the AEMG of MVIC. Two-way ANOVA was performed to assess the effects of groups (healthy and cLBP) and the three different target pressures of PBU. Independent sample t-test was conducted to compare between the two groups. Spearman's correlation analysis was performed in the cLBP group to determine potential correlations between EMG activity, NPRS and ODI.

RESULTS

The %MVIC of the TA and MF in the cLBP group were higher than the control group at each pressure value (P<0.05). During maximal voluntary isometric contraction (MVIC) of TA and MF, compared with healthy groups, cLBP subjects showed a decrease (TA mean = 47.61 μV; MF mean = 42.40 μV) in EMG amplitudes (P ≤ 0.001). The MVIC of MF was negatively correlated with Numerical Pain Rating Scale (r = - 0.48, P = 0.024) and Oswestry Disability Index (r = - 0.59, P = 0.004).

CONCLUSIONS

We measured the trunk muscles activities at different PBU pressure values, which allows the individual to estimate trunk muscle contraction via PBU. Clinicians may be able to confer the data obtained through EMG recordings to adjust the exercise intensity of PBU training accordingly.

Neuromuscular morphometric characteristics in low back pain with unilateral radiculopathy caused by disc herniation: An ultrasound imaging evaluation

BACKGROUND

Little is known about the neuromuscular morphometric characteristics in patients with sciatica.

OBJECTIVE

To evaluate the possible changes of nerve and muscle structures in patients with low back pain with unilateral radiculopathy due to lumbar disc herniation by ultrasound imaging.

DESIGN

A case-control observational study.

METHODS

Forty individuals were divided into case (n = 20; low back pain with unilateral radiculopathy due to disc herniation), and healthy control groups (n = 20). The thickness of lumbar multifidus at L5 level, and of lower limb muscles (i.e., biceps femoris, medial gastrocnemius, and soleus) was measured during both rest and full contraction to calculate the rest/contraction ratio of these muscles. Additionally, the sciatic nerve cross-sectional area and the echogenicity of the nerve and muscles were measured based on ultrasound imaging. The association between severity of low back pain radiculopathy (i.e., pain and patients' perceived disability) and rest/contraction ratio was assessed.

RESULTS

Patients with sciatica showed sciatic nerve enlargement, and different contraction ratios for multifidus (at L5)/ankle plantar flexors compared to the controls. The rest/contraction ratio for biceps femoris was similar between the two groups.

CONCLUSION

According to these findings, ultrasound imaging can be considered a useful tool to detect changes in the sciatic nerve and muscles due to disc herniation. Furthermore, regarding the observation of significant changes in muscle rest/contraction ratio in the multifidus and gastrosoleus, one might attribute these changes to the nerve root compression.

Intervertebral Disc Swelling Demonstrated by 3D and Water Content Magnetic Resonance Analyses after a 3-Day Dry Immersion Simulating Microgravity

Background: Vertebral deconditioning is commonly experienced after space flight and simulation studies. Disc herniation is quadrupled after space flight.

Purpose: The main hypothesis formulated by the authors is that microgravity results in intervertebral disc (IVD) swelling.

Study Design: The aim of the study was to identify the morphological changes of the spine and their clinical consequences after simulated microgravity by 3-day dry immersion (DI). The experimental protocol was performed on 12 male volunteers using magnetic resonance imaging and spectroscopy before and after DI.

Methods: All the experiment was financially supported by CNES (Centre national d'études spatiales i.e., French Space Agency).

Results: We observed an increase in spine height of 1.5 ± 0.4 cm and a decrease in curvature, particularly for the lumbar region with a decrease of −4 ± 2.5°. We found a significant increase in IVD volume of +8 ± 9% at T₁₂-L₁ and +11 ± 9% at L₅-S₁. This phenomenon is likely associated with the increase in disc intervertebral water content (IWC), 17 ± 27%. During the 3 days in DI, 92% of the subjects developed back pain in the lumbar region below the diaphragmatic muscle. This clinical observation may be linked to the morphological changes of the spine.

Conclusions: The morphological changes observed and, specifically, the disc swelling caused by increased IWC may contribute to understanding disc herniation after microgravity exposure. Our results confirmed the efficiency of the 3-day DI model to reproduce quickly the effects of microgravity on spine morphology. Our findings raise the question of the subject selection in spatial studies, especially studies about spine morphology and reconditioning programs after space flight. These results may contribute to a better understanding of the mechanisms underlying disc herniation and may serve as the basis to develop countermeasures for astronauts and to prevent IVD herniation and back pain on Earth.