The goal of this study was to compare and evaluate the effects of ultrasound (US) treatment applied at low-, medium- and high-power-pain threshold (HPPT) doses to trigger points in the treatment of myofascial pain syndrome (MPS). The study included 61 (40 female and 21 male) patients diagnosed with MPS, aged between 18 and 60 years. The patients were separated at random into three groups for the US application at different dosages. Group I patients received treatment of medium-dose US (1.5 Watt/cm(2)), Group II received HPPT US, and Group III received low-dose US (0.5 W/cm(2)). The patients were evaluated pre-treatment and 3 weeks after treatment in respect of visual analogue scale (VAS) scores, number of trigger points (NTP), pressure pain threshold (PPT), Range of Tragus-Acromioclavicular joint (RT-AJ) and neck pain disability scores (NPDS). A significant improvement was determined after treatment in all scores except PPT in Group I, in all scores in Group II, and only in the VAS score in Group III. When the groups were compared post-treatment in respect of improvement in NTP, VAS, RT-AJ and NPDS scores, Group II showed significant superiority over Group I, and Group I was determined to have significant superiority over Group III in respect of VAS, RT-AJ and NPDS scores (p < 0.05).
The study found that in the treatment of MPS, US therapy at HPPT dose can be considered as an alternative therapy method, which is more affordable and more effective than low-dose and conventional US therapy.