Background Active myofascial trigger points (MTrPs) are major pain generators in myofascial pain syndrome. Dry needling (DN) is an effective method for the treatment of MTrPs.
Objective To assess the immediate neurophysiological and clinical effects of DN in patients with upper trapezius MTrPs.
Methods This was a prospective, clinical trial study of 20 patients with upper trapezius MTrPs and 20 healthy volunteers (matched for height, weight, body mass index and age), all of whom received one session of DN. Primary outcome measures were neuromuscular junction response (NMJR) and sympathetic skin response (SSR). Secondary outcomes were pain intensity (PI) and pressure pain threshold (PPT). Data were collected at baseline and immediately post-intervention.
Results At baseline, SSR amplitude was higher in patients versus healthy volunteers (p<0.003). With respect to NMJR, a clinically abnormal increment and normal reduction was observed in patients and healthy volunteers, respectively. Moreover, PPT of patients was less than healthy volunteers (p<0.0001). After DN, SSR amplitude decreased significantly in patients (p<0.01), but did not change in healthy volunteers. A clinically important reduction in the NMJR of patients and increment in healthy volunteers was demonstrated after DN. PPT increased after DN in patients, but decreased in healthy volunteers (p<0.0001). PI improved after DN in patients (p<0.001).
Conclusions The results of this study showed that one session of DN targeting active MTrPs appears to reduce hyperactivity of the sympathetic nervous system and irritability of the motor endplate. DN seems effective at improving symptoms and deactivating active MTrPs, although further research is needed.
Trial registration number IRCT20130316128.
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Contributors MA-A was involved in the design of the work, delivered the intervention, collected and analysed the data and drafted the paper. NNA contributed to the design of the work, monitored data collection and revised the paper. SN designed the data collection tools and monitored data collection. GO contributed to the design of the work and data collection tools. MRN wrote the statistical analysis plan and revised the paper. All authors approved the final accepted version.
Funding This research was supported by the Tehran University of Medical Sciences.
Competing interests None declared.
Patient consent Obtained.
Ethics approval The Ethical Committee of Tehran University of Medical Sciences approved this study.
Provenance and peer review Not commissioned; externally peer reviewed.
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