Publications

Background: Optimal dry needling frequency for chronic mechanical neck pain remains uncertain, warranting dose–response testing.

Objectives: To investigate whether dry needling delivered once (DN1x) vs 3 (DN3x) times per week provides differential effects compared with sham DN on muscle stiffness and tone, pressure pain threshold (PPT), cervical range of motion, pain intensity, disability, and safety in chronic mechanical neck pain.

Methods: A multicenter, randomized, assessor- and participant-blinded trial allocated 96 participants to DN1x, DN3x, sham DN once weekly (sDN1x), or sham dry needling 3 times weekly (sDN3x) for 6 weeks. Primary outcomes were pain intensity and disability. Secondary outcomes included upper trapezius and levator scapulae pressure pain thresholds (PPT), stiffness and tone, and range of motion. Mixed-model ANOVAs tested group × time effects.

Results: Pain intensity decreased in both DN1x and DN3x (median pain intensity 6–2) compared with sham (no change), but without between-dose differences. Disability improved significantly over time in all groups (P < 0.001, partial η² = 0.554) with no group differences (all P > 0.05). At 6 weeks, DN3x produced greater reductions in muscle stiffness and tone than sham (group × time, P < 0.01, partial η² up to 0.20). For PPT, a significant group × time effect was found (P = 0.008, partial η² = 0.116). DN3x increased trapezius PPT by +7.19 kg/cm² from baseline (P < 0.001), significantly higher than sDN1x (P < 0.001) and sDN3x (P < 0.001). Cervical extension showed a group × time interaction (P = 0.004), favoring DN3x over sham at week 6. No serious adverse events occurred; 133 mild events (eg, soreness, bruising) were reported, all in DN groups and more frequent with DN3x.

Conclusions: In acute cervical myofascial pain, DN1x and DN3x did not show superiority over sham for the primary outcomes of pain intensity and disability over 6 weeks. Higher-frequency DN yielded greater improvements in tissue-level outcomes and PPT, and modest improvements in cervical extension, but with milder adverse events. The added value of higher frequency appears outcome-specific.

Trial Registration: ISRCTN16484644.

Keywords: musculoskeletal disorders, trigger point therapy, muscle properties, neck disability index, sham intervention

In this randomized controlled trial of adults with acute cervical myofascial pain syndrome, DN1x and DN3x did not show superiority over sham for the primary patient-reported outcomes of pain intensity and neck disability over six weeks. DN3x produced greater improvements in secondary tissue-level outcomes (muscle stiffness and tone), pressure pain thresholds, and cervical extension, but was associated with a higher cumulative burden of mild adverse events due to greater treatment exposure. Thus, any incremental value of increasing session frequency appears confined to secondary biomechanical and hypoalgesic outcomes, and its clinical relevance for symptoms and function remains uncertain. In the longer term, pragmatic trials that embed DN within multimodal rehabilitation are warranted.