Comparison of immediate and delayed effects of superficial and deep dry needling in patients with upper trapezius myofascial trigger points

Background: Dry needling is one of the most common treatments for this condition. In this study the immediate and delayed effects of superficial dry needling (SDN) and deep dry needling (DDN) on upper trapezius muscle function and patients' pain and disability was evaluated.Methods: In this quasi-experimental study, 47 women with active MTrPs were randomly divided into SDN and DDN groups and received one session treatment. Pain and disability were assessed before and one week after intervention with visual analogue scale (VAS) and neck disability index (NDI) questionnaire. Muscle activity was assessed by surface electromyography (sEMG) before, immediately and one week after intervention.Results: Both groups showed significant decrease in VAS (p < 0.001) and NDI (p < 0.001) after one week, however no significant difference were found between the groups (p > 0.05). A significant increase in sEMG activity was observed only in DDN group after one week (p < 0.007), but there were no significant differences in sEMG activity in SDN group after intervention and between the two groups (p > 0.05). Conclusion: Both SDN and DDN could be effective in reducing pain and disability in patients with active MTrPs of upper trapezius muscle. Regarding muscle function DDN seems to be more effective. So that based on evaluation of the therapist in some cases with not significant muscle dysfunction SDN as a gentle and less invasive method could be used but for long term effectiveness and in those with significant muscle dysfunction DDN could be used.