Dry needling versus magnesium sulfate iontophoresis of active trigger points of the axioscapular muscle in neck pain: a single blind randomized controlled trial.

OBJECTIVE

To compare the effects of dry needling (DN) and magnesium sulfate (MgSO4) iontophoresis on pressure pain threshold (PPT), neck disability, pain intensity and muscle activity/amplitude in patients with upper-trapezius active myofascial trigger points (MTrPs) and neck pain.

METHODS

Sixty subjects with neck pain and cervical myofascial pain syndrome (MPS) of the upper trapezius muscles were randomly assigned into a DN group that received DN and stretching of all cervical muscles, an iontophoresis group that received MgSO4 iontophoresis and stretching of all cervical muscles or a control group C that received only stretching of all cervical muscles. The subjects received the treatment twice a week for 4 weeks. PPT, Arabic neck disability index (ANDI), pain intensity visual analogue scale (VAS) and cervical muscle amplitude (assessed by electromyography and expressed as a normalized root mean square (RMS)) were measured before and after completion of the treatment.

RESULTS

In the within-group analysis, there were statistically significant differences pre- versus post-treatment in all variables in both experimental groups (p < 0.05) but no significant differences in the control group with the single exception of pain intensity. In the between-group analysis post-treatment, there were statistically significant differences between all three groups. Compared with the iontophoresis group, the DN group showed significant improvements in VAS (mean difference (MD) -2.0, 95% confidence interval (CI) -2.84 to -1.36; p < 0.01), RMS (MD -1.32, 95% CI -1.79 to -0.85; p < 0.001), ANDI (MD -2.60, 95% CI -4.50 to -0.70; p = 0.004) and PPT (MD 1.48, 95% CI 1.01-1.95; p < 0.001).

CONCLUSION

DN and MgSO4 iontophoresis both had positive effects on PPT, ANDI, VAS and muscle amplitude in the treatment of neck pain subjects with upper-trapezius MTrPs. DN had a superior effect than MgSO4 iontophoresis for all outcomes studied.