Effects of needle electrical intramuscular stimulation on shoulder and cervical myofascial pain syndrome and microcirculation

Background: To evaluate the effects of needle electrical intramuscular stimulation (NEIMS) on myofascial trigger points (MTrPs) and their epidermal blood flow. Methods: Forty adult patients with active MTrPs in the upper trapezius or levator scapulae underwent 4 weekly NEWS sessions. Visual analog scale (VAS) and pain pressure threshold (PPT), along with cervical and shoulder range of motion (ROM) were used as outcome measures. Microcirculatory changes were also evaluated by laser Doppler flowmetry of the epidermal area above these MTrPs. Data were collected before and after each treatment. Paired t tests were used to compare pre- and post-treatment data. Outcomes were presented as box plots displaying medians and 25(th) to 75(th) percentile values. Results: VAS and PPT pain significantly improved immediately after each treatment; effects persisted till the end of the experiment. NEIMS treatment also had immediate and mid-term positive effects on cervical and shoulder ROM. There was an overall negative correlation between epidermal blood flow and VAS score before the first treatment. Regional blood flow significantly increased immediately but temporarily after each treatment. Conclusion: NEIMS did have positive effects on myofascial pain syndrome, but the data did not indicate that increased regional microcirculation was the possible therapeutic mechanism.