Comparison of the Effect of Bicarbonate, Hyaluronidase, and Lidocaine Injection on Myofascial Pain Syndrome

BACKGROUND: Myofascial pain syndrome is a chronic syndrome that occurred in a local or focal part of the body. The basis for myofascial pain syndrome is the presence of myofascial trigger point or points, producing pain in clinical examinations. OBJECTIVES: This study aimed to compare the effect of injection of bicarbonate, hyaluronidase, and lidocaine on myofascial pain syndrome. METHODS: The patients were randomly allocated to three groups of bicarbonate, hyaluronidase, and lidocaine. The injection was done at two painful regions of trapezius muscle with a sonography guide for each patient. The values of visual analogue scale (VAS), pre-injection range of motion (ROM), immediately after injection, second and fourth week were measured. RESULTS: The analysis showed that there were no significant differences between the three groups for age, gender, BMI, and height (P > 0.05). Repeated measures one-way ANOVA (week * group) 4 * 3 was used to compare the effect of bicarbonate, hyaluronidase, and lidocaine on VAS and range of motion (ROM) before injection, immediately after injection, second and fourth week. The results showed that the main effect of group and week is significant for VAS (P < 0.05). This study showed that the values of VAS were significantly different between the three groups during the fourth weeks of the study. Moreover, the patients experienced more pain decline in the hyaluronidase group during weeks before injection, after injection, second and fourth week, which indicated the permanent effect of this medication on pain decline. CONCLUSIONS: Injection of lidocaine leads to a significant reduction in pain immediately after injection; however, the decline was not permanent and disappeared in the following four weeks. But VAS reduction in hyaluronidase group more than bicarbonate and lidocaine groups.