Therapeutic effect of focused-extracorporeal shockwave therapy on muscular and adjacent tissue stiffness and pain changes in myofascial pain syndrome: A randomized controlled trial study

Background: Focused-extracorporeal shockwave therapy (fESWT) has recently been applied in the management of chronic pain. However, its effectiveness in reducing muscular stiffness and pain among office workers has not been extensively studied. This study aimed to investigate the effectiveness of fESWT and sham-fESWT in alleviating muscular stiffness, pain, and functional disability. Methods: Sixty-four office workers (mean age 31.4 ± 9.5 years) with myofascial pain syndrome of the upper trapezius were randomly and equally assigned to receive either the fESWT or sham-fESWT. The interventions were administered once a week for 4 weeks, with 4 Hz frequency and a total energy of 0.1[sbnd]0.232 mJ/mm². Measurements were recorded at baseline, immediately after treatment, at two weeks, and at four weeks, assessing shear modulus (tissue stiffness), visual analogue scale (VAS), and the neck disability index (NDI). Results: The result demonstrated a significant acute decrease in shear modulus at the trigger point ([sbnd]6.1 kPa, p = 0.009) and a delayed reduction in muscle stiffness of the lower aponeurosis ([sbnd]5.3 kPa, p = 0.004) following 4 weeks. Additionally, VAS scores decreased at all time points following fESWT (p < 0.05), while the sham-fESWT group also demonstrated reductions during the final two weeks. NDI showed a decrease in both groups after four sessions (p < 0.05), with no group effect. Conclusion: fESWT was effective in reducing muscular pain, stiffness, and functional disability in patients. However, the potential psychological effects of sham-fESWT on VAS and function should be considered. Further research is necessary to determine the optimal treatment sessions and intensity of fESWT to better establish its efficacy.