Comparison of the Effects of Dry Needling and Low-Level Laser on the Latent Trigger Points of Upper Trapezius

Background: Myofascial pain syndrome (MPS) is one of the most frequent causes of chronic musculoskeletal pain which is characterized by myofascial trigger points (MTrPs). Hence, it is of crucial importance to identify practical approaches for the treatment of these points. Upper trapezius muscle (UT) is highly susceptible to the development of MTrPs that are commonly resulted from overuse and micro-trauma. Objectives: The present study aimed to compare the effects of dry needling (DN) and low-level laser therapy (LLLT) regarding the reduction of pain and muscle thickness and improvement of the range of motion (ROM) and pressure pain threshold (PPT) in patients with latent MTrPs (LTrPs) in their UT muscles. Methods: In total, 60 patients with LTrPs in UT muscle participated in this randomized clinical trial. The subjects were randomly divided into two treatment groups of DN and LLLT. The PPT was evaluated by visual analog scale (VAS) and algometer while ROM and muscle thickness were assessed using goniometer and ultrasonography, respectively. It should be noted that the variables were evaluated before the first and after the sixth sessions. Finally, the collected data were analyzed using independent and paired t-tests. Results: Based on the results, the VAS and muscle thickness significantly reduced, while the PPT and cervical ROM increased in both groups after treatment (P<0.001). The independent t-test revealed a statistically significant improvement in the DN group in terms of PPT (9.9-14.17, P=0.009) and ROM (37.33-42.67, p=0.005), compared to the LLLT group. Nevertheless, no significant difference was found between the two groups regarding VAS and muscle thickness variables (P>0.05). Conclusion: The DN and LLLT effectively improved symptoms in the UT muscles of patients with LTrPs. However, the DN was more effective in the improvement of ROM and PPT variables.