The Effect of Extracorporeal Shock Wave Therapy on Myofascial Pain Syndrome

Objective To investigate the effect of extracorporeal shock wave therapy (ESWT) on myofascial pain syndrome (MPS). Method Thirty patients with MPS in trapezius muscle were randomly divided into two groups, ESWT group (n=15), and trigger point injections (TPI)+transcutaneous electrical nerve stimulation (TENS) group (n=15). For a total of 3 weeks, ESWT was undertaken with 1,500 pulse each time at one week interval totaling 4,500 pulse, TPI for once a week totaling tkree times and TENS for five times a week totaling three weeks. Results The changes in pain threshold (lb/cm(2)) showed the values of 6.86 +/- 1.35 before first therapy, 11.43 +/- 0.27 after first therapy, and 12.57 +/- 0.72 after third therapy, while TPI+TENS group showed the values of 6.20 +/- 1.92 before first therapy, 8.80 +/- 0.48 after first therapy, and 9.60 +/- 2.19 after third therapy, and the changes between the groups were significantly different (p=0.045). The changes in visual analog scale were estimated to be 6.86+0.30 before first therapy, 2.86 +/- 0.90 after first therapy, and 1.86 +/- 0.69 after third therapy in case of ESWT group, whereas the figures were estimated to be 7.20+1.30 before first therapy, 4.60+0.55 after first therapy, and 2.80+0.84 after third therapy in case of TPI+TENS group, and the changes between the groups were significantly different (p=0,010). The changes in McGill pain questionnaire (p=0.816) and pain rating scale (p=0.644) between the groups were not significantly different The changes in neck ROM were also not significantly different between the groups (p > 0.05). Conclusion The ESWT in patients with MPS in trapezius muscle are as effective as TPI and TENS for the purpose of pain relief and improving cervical range of motion.