• Hadizadeh M
• Rahimi A
• Velayati M
• Javaherian M
• Naderi F
• Keshtkar A
• Dommerholt J

• Affiliation / Bethesda Physiocare, Inc.
• Affiliation / Myopain Seminars
• Affiliation / Shahid Beheshti University of Medical Sciences. School of Rehabilitation. Department of Physiotherapy
• Affiliation / Tehran University of Medical Sciences. School of Public Health. Department of Health Sciences Education Development
• Affiliation / University of Maryland. School of Medicine. Department of Physical Therapy and Rehabilitation Science
• Dry Needling
• Electric Stimulation Therapy
• Myofascial Pain Syndromes
• Open Access Document
• Superficial Back Muscles
• Trigger Points
• Ultrasonography

Background: The most common cause of muscle pain is myofascial pain syndrome. Myofascial pain syndrome caused by sensitive areas called trigger points (TrP). Some physiotherapy modalities have acceptable effects for this disorder, but it is necessary to check the effects of placebo, appropriate dose, and long-term effects for each intervention. The aim of this study is to investigate the effect of intramuscular electrical stimulation (IMES) compared to dry needling (DN) on sonographic and clinical parameters in upper trapezius muscle TrP.

Methods: This is a randomized, single-blind control trial. The study period was from December 2, 2020, to April 10, 2021. Thirty volunteer patients with active upper trapezius TrP were randomly allocated into two groups: (1) IMES, (2) DN. Participants received interventions in three sessions. Primary outcome measurements were neck range of motion (ROM) and TrP circumference. Secondary outcome measurements were pain by visual analog scale (VAS), pain pressure threshold (PPT), disability, TrP longitudinal and transverse diameter, TrP stiffness, and muscle blood flow by vascular resistance index (RI). All outcome measurements were evaluated before, after, and one month after the intervention. If the data were normal, the repeated measure ANOVA test was used; if data were not normal, the Friedman test and the Kruskal-Wallis test was used. A significance level of 0.05 has considered.

Results: ROM increment was significantly more in the IMES group. TrP circumference decrement was significantly more in the IMES group. VAS changes did not show significant difference between two groups. The PPT improvement was significantly more in the IMES group. Disability changes were not significant. Longitudinal diameter changes were significantly more in the IMES group. TrP stiffness changes were not significant. The vascular RI decreased significantly in IMES group.

Conclusion: It seems that both IMES and DN have promising effects for improving upper trapezius TrPs. However, IMES is more effective in some clinical and ultrasound parameters. In order to investigate the effects of this intervention more precisely more studies are necessary.

Trial registration: This study was prospectively registered at Iranian registry of clinical trials (IRCT: IRCT20170616034567N2).

Author keywords: Trigger point - Myofascial pain - Intramuscular electrical stimulation - Dry needling - Ultrasound imaging - Upper trapezius

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