Efficacy of EMLA cream phonophoresis comparison with ultrasound therapy on myofascial pain syndrome of the trapezius: a single-blind, randomized clinical study

The aim of this study is to investigate whether eutectic mixture of local anesthetics (EMLA) cream phonophoresis superior to conventional US over the trigger points (TPs) in terms of improvements of pain, range of motion and disability in myofascial pain syndrome (MPS). Fifty patients (42 female, 8 male) diagnosed with MPS were included in the study. Patients were randomly assigned into two treatment groups including phonophoresis (PH) group (n = 25) and ultrasound (US) group (n = 25). PH group received EMLA cream phonophoresis (2.5 % lidocaine, 2.5 % prilocaine); US group received conventional ultrasound therapy over the all active TPs on trapezius muscle for 10 min a day for 15 sessions. Outcome measures were performed before the treatment course and at the end of a 15-session course of treatment. Student T, Mann–Whitney U, chi-square and Wilcoxon tests were used for statistical analysis. At the end of the therapy, there was statistically significant decrease in both PH group and US group in terms of number of trigger point (NTP) (p = 0.001, p = 0.029), pain intensity on movement (p = 0.001 vs. 0.002) and right/left cervical lateral ROMs (p = 0.001/p = 0.001, p = 0.009/p = 0.020) relative to baseline. The NTP decrease in PH group was significantly higher than that in US group (1.84 ± 1.46 vs. 0.72 ± 1.45; p = 0.01). Pain intensity at rest (p = 0.001) and NPDI scores (p = 0.001) were statistically improvement in only PH group. EMLA cream phonophoresis is more effective than conventional ultrasound therapy in terms of pain and associated neck disability, and it seems the complementary treatment option for MPS.