Effects of Percutaneous and Transcutaneous Electrical Nerve Stimulation on Endogenous Pain Mechanisms in Patients with Musculoskeletal Pain: A Systematic Review and Meta-Analysis

Abstract

Objectives The main aim was to determine the effects of percutaneous (PENS) and transcutaneous (TENS) electrical nerve stimulation on endogenous pain mechanisms in patients with musculoskeletal pain. Design A systematic review and meta-analysis. Methods The search was conducted on March 1, 2022, in EMBASE, CINAHL, PubMed, PEDro, Cochrane Library, Web of Science, Medline and SCOPUS databases. Randomized controlled trials (RCTs) comparing the use of transcutaneous or percutaneous electrostimulation with a placebo, control group or standard treatment in patients with musculoskeletal pain were included. Outcome measurements were QST somatosensory variables like pain threshold at pressure (PPT), conditioned pain modulation (CPM) and temporal summation of pain (TSP). The pooled data were evaluated with Review Manager 5.4. Results Twenty-four RCTs (N = 24) were included in the qualitative analysis and 23 in the meta-analysis. The immediate effects of PENS and TENS on local PPTs were significant with a moderate effect size (SMD 0.53, 95% CI: 0.34 to 0.72, p < 0.00001). When only studies with a lower risk of bias were analyzed, the heterogeneity from I2=58% (P < 0.00001) to I2=15% (P = 0.01) and a decrease in the overall effect was observed (SMD 0.33, 95% CI: 0.7 to 0.58). The short-term effects on local PPTs were not significant when compared to the control group (P = 0.13). The mid-term effects on local PPTs were significant showing a large effect size (SMD 0.55, 95% CI: 0.9 to 1.00, p = 0.02). The immediate effects on CPM were significant with a large effect size (SMD 0.94, 95% CI: 0.48 to 1.41, p < 0.0001). Conclusion PENS and TENS have a mild-moderate immediate effect on local mechanical hyperalgesia in patients with musculoskeletal pain. It appears that these effects are not sustained over time. Analyses suggest an effect on central pain mechanisms producing a moderate increase in remote PPT and in the case of PENS on CPM, but further studies are needed to draw clearer conclusions.

Ultrasound‐guided percutaneous electrical nerve stimulation versus surgery for women with unilateral carpal tunnel syndrome: A randomized parallel‐group trial

“…First, it is possible that PENS could reduce nerve excitability (the median nerve) by altering nociceptive input and reducing neurogenic inflammation or ectopic discharge (García‐Collado et al, 2022). A recent meta‐analysis has concluded that PENS seems to be able to modulate altered pain processing by decreasing pain sensitivity and activating conditioning pain modulation, although further studies are needed to confirm this (Lagos et al, 2022). In fact, preliminary data suggest that manual therapy can modulate pain processing (Arribas‐Romano et al, 2020).…”

Transcranial Direct Current Stimulation (tDCS) Effects on Quantitative Sensory Testing (QST) and Nociceptive Processing in Healthy Subjects: A Systematic Review and Meta-Analysis

“…In the absence of SD of the difference, we imputed from other data reported in the study: (1) using other measures reported in the study (e.g., confidence intervals and p values, following the principles described in Chapter 6.5.2.2 of the Cochrane Handbook) [36]; or, if that was not possible, (2) using the correlation coefficient of the most similar study included (following the principles described in Chapter 6.5.2.8 of the Cochrane Handbook) [36]; or if that was not possible, (3) using a conservative correlation coefficient of 0.5 [37]. This methodology has been performed in other meta-analyses [38].…”

“…Regarding current density, five applied a current density of 0.028 mA/cm 2 [21,24,41,45], two applied 0.04 mA/cm 2 [19,44], nine applied 0.057 mA/cm 2 [5,25,26,40,46,47,50,57], and one applied 0.1 mA/cm 2 [53]; the rest of the studies did not report current density. Regarding stimulation time, one applied tDCS for 7 min [38], three for 10 min [23,52], five for 15 min [21,24,41,45,57], eighteen for 20 min [5,9,19,22,26,[42][43][44][47][48][49][50][51][53][54][55][56], and one for 40 min [46]. Most studies conducted single treatment sessions [5,17,19,21,23,25,26,…”

Anatomo-physiological basis and applied techniques of electrical neuromodulation in chronic pain

“…Despite its potential benefits in pain management, the precise indications for PENS, as well as the most effective treatment parameters, remain topics of discussion and investigation within the medical community. Additionally, comparative studies evaluating PENS against other therapeutic modalities are limited, leaving uncertainties about its relative efficacy and place in treatment algorithms [ 189 , 193 , 194 ]. To address these gaps in knowledge, future research efforts should prioritize well-designed studies that investigate the clinical utility of PENS across various pain conditions.…”

“…To address these gaps in knowledge, future research efforts should prioritize well-designed studies that investigate the clinical utility of PENS across various pain conditions. These studies should aim to delineate the specific patient populations most likely to benefit from PENS, identify optimal stimulation parameters, and compare its efficacy and safety to other established treatments [ 189 , 193 , 194 ]. Furthermore, incorporating mechanistic studies to elucidate the underlying pathways through which PENS exerts its therapeutic effects can provide valuable insights into its mode of action and potential advantages over alternative interventions.…”