TheEffectofElectricStimulationTechniquesonPainandTendernessattheMyofascialTriggerPoint:ASystematicReview

Myofascial pain is a highly prevalent chronic pain condition affecting 30-93% of patients in pain clinics. It's characterized by myofascial trigger points (MTrPs), which are tight, hypersensitive bands of skeletal muscle that cause pain and restrict movement. These trigger points develop from poor posture, stress, overexertion, or trauma, creating an "energy crisis" in the muscle that prevents proper relaxation. Current evidence suggests that electrical stimulation techniques like TENS (transcutaneous electrical nerve stimulation) and electroacupuncture might help by blocking pain signals and improving blood flow to affected muscles.

However, no comprehensive systematic review had examined the effectiveness of electrical stimulation specifically for myofascial pain.

The researchers conducted a thorough systematic review searching three major medical databases (Medline, EMBASE, and Cochrane CENTRAL) for randomized controlled trials testing electrical stimulation on myofascial pain. They used strict inclusion criteria, only including studies with myofascial pain patients receiving various forms of electrical stimulation (TENS, electroacupuncture, PENS) compared to sham/placebo treatments. Two reviewers independently screened 377 studies and extracted data from 15 qualifying trials involving 574 participants. They assessed study quality using standard bias assessment tools and performed statistical analysis to combine results, calculating standardized mean differences to compare pain intensity outcomes across different types of electrical stimulation.

The analysis revealed that electrical stimulation techniques overall provided statistically significant pain relief (P=0.03) compared to sham treatments. However, when broken down by treatment type, electroacupuncture showed much stronger effects (P=0.02) with moderate effect sizes, while TENS alone was not statistically significant (P=0.17) despite trending toward improvement. Seven studies with 341 participants contributed to the quantitative analysis of pain intensity scores. The review also found that treatment sessions longer than 15 minutes appeared more effective than shorter sessions, and high-frequency stimulation (>50Hz) seemed more promising than low-frequency stimulation, though the evidence was limited.

Studies showed considerable variation in treatment parameters, locations, and outcomes, making it difficult to determine optimal stimulation settings.

This systematic review provides the first comprehensive evidence that electrical stimulation can help reduce pain in people with myofascial trigger points, but the type of stimulation matters significantly. Electroacupuncture, which delivers electrical stimulation through acupuncture needles placed at specific points, appears more effective than surface TENS electrodes for myofascial pain relief. This may be because the needles can reach deeper tissues and target the nerve pathways more directly involved in trigger point pain. For patients, this suggests that while TENS might provide some benefit, electroacupuncture could offer more substantial pain relief.

For clinicians, the findings support using electrical stimulation as part of myofascial pain treatment, particularly electroacupuncture when available and appropriate. However, more research is needed to determine optimal treatment parameters, session frequency, and duration for different types of electrical stimulation.