Aim: Myofascial pain syndrome (MPS) is a frequent cause of chronic muscoloskeletal pain. Transcutaneous electrical nerve stimulation (TENS) is one of the most frequently employed treatments in MPS. The aim of this study is to compare the short and medium-term effects of frequency modulated neural stimulation (FREMS) to those of TENS in MPS.
Methods: Forty subjects with upper trapezius MPS were randomly allocated to 1 of 2 groups, treated with either FREMS (n=19) or TENS (n=21). Each treatment consisted in 10 sessions lasting 20 min each. Patients were evaluated before treatment, at 1 week, and at 1 and 3 months after the end of treatment. Clinical evaluation included parameters for measurement of pain levels using the neck pain and disability visual analogue scale (NPDVAS) and algometry, evaluation of myofascial trigger point characteristics and measurement of the range of cervical movement (range of motion, ROM).
Results: The FREMS group showed a significant improvement in the NPDVAS, algometry, in myofascial trigger point characteristics, and in the ROM (homolateral rotation, controlateral rotation, bending and extension) after the end of treatment and at 1 and 3 months follow-up evaluation. The TENS group showed significant improvement in the same outcome measures except for algometry and cervical extension, but these improvements were maintained only at the 1 month follow-up evaluation. However, were not observed statistically significant differences between FREMS of TENS in many of outcome measures.
Conclusions: Both FREMS and TENS have positive short-term effects on MPS. But, medium-term effects were achieved only with FREMS.