Electrical stimulation, particularly electroacupuncture, was found to alleviate pain at myofascial trigger points, according to a systematic review published in Pain Medicine.
To evaluate the efficacy of electrical stimulation in patients with chronic myofascial pain, the researchers conducted a systematic review of 15 randomized controlled studies in which the efficacy of electroacupuncture (n=2) or transcutaneous electrical stimulation (n=13) on pain at myofascial trigger points was examined (n=170 patients treated with an experimental intervention; n=171 patients receiving a control intervention).
Standardized mean differences (SMDs) were calculated for studies in which pain intensity was documented in order to normalize data from the studies analyzed. The overall SMD was –0.23 (95% CI, −0.45 TO −0.2; P =.03) in favor of experimental vs control intervention. The SMD was in favor of experimental vs control intervention for electroacupuncture (SMD, −0.64; 95%CI, −1.18 to −0.09; P =.02) and for transcutaneous electric stimulation, although it did not reach significance (SMD, −0.16; 95% CI, −0.39 to 0.07; P =.17).
Electroacupuncture was found to have moderate but significant effect sizes (P =.01) and transcutaneous electric stimulation small or negligible effect sizes. It was noted that there was wide variability across studies in which the effects of transcutaneous electrical stimulation were examined. In addition, high-frequency and low-frequency electrical stimulation were found to provide similar improvements, although high-frequency might be marginally more effective. The reviewers determined via subgroup analysis that the rate and number of treatments might not influence pain intensity, but rather treatment duration could be largely responsible for efficacy of treatment.
Limitations to this review include the potential for bias and population heterogeneity.
“Our review demonstrated that electric stimulation techniques are effective overall and offer a greater degree of pain relief relative to transcutaneous electric[al] stimulation…Future studies should assess the effects of electric stimulation at various anatomical regions implicated in the pathophysiology of the trigger point,” concluded the study authors.
Ahmed S, Haddad C, et al. The effect of electric stimulation techniques on pain and tenderness at the myofascial trigger point: A systematic review [published online January 25, 2019]. Pain Medicine. doi:10.1093/pm/pny278