EffectofDifferentTranscutaneousElectricalStimulationModalitiesonCervicalMyofascialPainSyndrome

Myofascial pain syndrome (MPS) affects about 85% of the population and is characterized by trigger points in muscles that cause pain, muscle spasm, decreased range of motion, and fatigue. The cervical (neck) region is one of the most commonly affected areas. Transcutaneous electrical nerve stimulation (TENS) is a popular treatment because it's inexpensive, safe, and easy to use. However, there's ongoing debate about whether different types of TENS are more effective than placebo treatments, and which specific TENS parameters work best for cervical MPS.

The researchers conducted a randomized, placebo-controlled trial with 80 patients who had chronic neck pain from myofascial pain syndrome lasting longer than three months. Participants were randomly divided into four equal groups of 20 patients each. Group 1 received conventional TENS (100 Hz frequency, low intensity); Group 2 received acupuncture-like TENS (4 Hz frequency, high intensity); Group 3 received burst TENS (combining 100 Hz and 2 Hz frequencies, high intensity); and Group 4 received placebo TENS (patients felt initial stimulation but then the current was secretly turned off while they were told it was continuing). All groups received 10 treatment sessions over 3-4 weeks, with each session lasting 30 minutes.

Electrodes were placed on trigger points on both sides of the neck. Both patients and evaluating physicians were blinded to which treatment was being given.

Of the 80 patients who started the study, 75 completed it (5 dropped out due to work scheduling conflicts). The results showed no significant differences between any of the TENS groups or the placebo group. Pain scores on a 0-10 visual analog scale remained essentially unchanged in all groups after treatment. For example, the conventional TENS group went from 7.12 to 6.85 (not statistically significant), while the placebo group went from 7.56 to 6.95 (also not significant).

Quality of life measures using the SF-36 bodily pain subscale also showed no meaningful improvements in any group. Importantly, none of the active TENS treatments performed better than the placebo treatment.

This study suggests that TENS therapy alone may not be effective for treating cervical myofascial pain syndrome. The fact that all three different types of TENS performed no better than placebo indicates that the electrical stimulation itself may not provide meaningful pain relief for this condition. This challenges the common clinical practice of using TENS as a standalone treatment for neck trigger points. The researchers concluded that TENS alone has no role in cervical MPS therapy and suggested that other treatment approaches should be considered.

For patients with neck trigger points, this means they may need to look beyond TENS to other evidence-based treatments like trigger point injections, dry needling, manual therapy, or exercise programs. For clinicians, these results suggest that while TENS may still be used as part of a comprehensive treatment plan, it should not be relied upon as a primary intervention for cervical myofascial pain.