Extracorporeal Shock Wave Therapy in Myofascial Pain Syndrome of Upper Trapezius

OBJECTIVE To evaluate the effect of extracorporeal shock wave therapy (ESWT) in myofascial pain syndrome of upper trapezius with visual analogue scale (VAS) and pressure threshold by digital algometer. METHOD Twenty-two patients diagnosed with myofascial pain syndrome in upper trapezius were selected. They were assigned to treatment and standard care (control) groups balanced by age and sex, with eleven subjects in each group. The treated group had done four sessions of ESWT (0.056 mJ/mm(2), 1,000 impulses, semiweekly) while the control group was treated by the same protocol but with different energy levels applied, 0.001 mJ/mm(2). The VAS and pressure threshold were measured twice: before and after last therapy. We evaluated VAS of patients and measured the pressure threshold by using algometer. RESULTS There were two withdrawals and the remaining 20 patients were three men and 17 women. Age was distributed with 11 patients in their twenties and 9 over 30 years old. There was no significant difference of age, sex, pre-VAS and pre-pressure threshold between 2 groups (p>0.05) found. The VAS significantly decreased from 4.91±1.76 to 2.27±1.27 in the treated group (p<0.01). The control group did not show any significant changes of VAS score. The pressure threshold significantly increased from 40.4±9.94 N to 61.2±12.16 N in the treated group (p<0.05), but there was no significant change in the control group. CONCLUSION ESWT in myofascial pain syndrome of upper trapezius is effective to relieve pain after four times therapies in two weeks. But further study will be required with more patients, a broader age range and more males.