Chronic low back pain (CLBP) affects paraspinal muscle size, quality (e.g., fatty infiltration), range of motion (ROM), and strength. Although transcutaneous electrotherapies are used to treat CLBP, their effects on paraspinal-related outcomes are not fully known. The aim of this systematic review and meta-analysis was to assess the overall effect of transcutaneous electrotherapies on trunk/lumbar ROM, paraspinal muscle morphology, and trunk muscle function (including strength and endurance) in CLBP patients. A systematic search of four databases and two study registers was conducted between 1 February 2022 and 15 September 2022. Two reviewers were responsible for screening and data extraction. Of the 3939 independent records screened, 10 were included in the systematic review and 2 in the meta-analysis. The results suggest there is limited evidence that both EMS and EMS plus exercise are superior to passive and active controls, respectively, for improving trunk muscle endurance. There is limited evidence that neither TENS nor mixed TENS are superior to controls for improving trunk muscle endurance. There is limited evidence that NMES is superior to passive controls for improving trunk muscle strength. The effect of transcutaneous electrotherapy on the other investigated outcomes was inconclusive. Future transcutaneous electrotherapy studies should focus on paraspinal-based outcomes that are under-studied.

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.

Background: Chronic low back pain (CLBP) patients present with morphological and functional deficits to the lumbar multifidus. Electromyostimulation (EMS) can be used to improve activation and strength in atrophied skeletal muscle, but its effect on multifidus morphology and function in CLBP patients is understudied. The aims of this study were to compare the effect of two EMS protocols on lumbar multifidus morphology, function, and patient-reported outcomes. Methods: Two-arm randomized control trial (RCT). Individuals with CLBP were randomized to receive either the ‘phasic’ or ‘combined’ muscle therapy protocol with the StimaWELL 120MTRS, a medium-frequency EMS device. T-tests and non-parametric equivalents were used to assess change in imaging-based outcomes, and a repeated-measures ANOVA was used for patient-reported outcomes. Results: Apart from a significant within-group decrease in fatty infiltration at left L5-S1 in the combined group (MD = −1.51, 95% CI = −2.79, −0.23, p = 0.024), results revealed no significant within- or between-group changes to multifidus morphology or function. Pairwise comparisons revealed that both groups experienced significant improvements in multiple pain outcome measures, with a significant group*time effect for LBP with sitting (p = 0.019) and pain interference (p = 0.032) in favor of the phasic group. Additionally, there were significant improvements in the phasic group in disability, pain interference, and pain catastrophizing (all p < 0.01). Conclusions: A 10-week EMS intervention produced no between-group differences in multifidus muscle morphology or function. Participants in both groups experienced significant improvements in a variety of patient-reported outcomes.