Low-Intensity Continuous Ultrasound for the Symptomatic Treatment of Upper Shoulder and Neck Pain: A Randomized, Double-Blind Placebo-Controlled Clinical Trial

PURPOSE: Low-intensity continuous ultrasound (LICUS) is an emerging high-dosimetry ultrasound-based therapy for accelerated tissue healing and the treatment of myofascial pain. In this study, LICUS treatment is clinically evaluated for chronic upper neck and shoulder pain in a randomized, multi-site, double-blind, placebo-controlled study. PATIENTS AND METHODS: CONSORT guidelines were followed in conducting and reporting the clinical trial. Thirty-three participants with upper trapezius myofascial pain were randomized for treatment with active (n=25) or placebo (n=8) devices. Investigators and subjects were blinded to treatment groups. Participants self-reported pain daily, rating from 0–10 on the numeric rating scale. If pain rating was more significant than or equal to 3, the LICUS (3MHz, 0.132W/cm(2), 1.3W, 4 hours) was self-applied for total energy dosimetry of 18,720 Joules per treatment. During the 4-week study, daily pain rating was recorded. If LICUS treatment was delivered, pain before, during, and after treatment were recorded as well as the global rate of change (GROC). Independent t-tests were used to assess change from baseline and differences between treatment groups. ClinicalTrials.gov: NCT02135094. RESULTS: There was a 100% completion rate for participants enrolled in the study and no significant differences between the groups regarding demographic variables or baseline outcome measures. Participants treated with active therapy observed a significant mean pain reduction from baseline of 2.61 points for active (p<0.001), compared to 1.58 points decrease from baseline for placebo (p=0.087), resulting in a 1.03 points significant decrease in the active group over placebo (p=0.003). The total GROC was significantly higher in the active group at 2.84 points compared to the placebo group at 0.46 points (p<0.001). CONCLUSION: Low-intensity continuous ultrasound treatment significantly reduced pain in patients with upper trapezius myofascial pain of the neck and shoulder. LICUS treatment showed a clinically meaningful improvement in the GROC scores for patients. The results from this clinical trial indicate that the LICUS treatment of 18,720 Joules can effectively be used to treat clinical pain related to upper trapezius myofascial pain. Further research could investigate varying dosimetry to improve efficacy and/or reduce the dose.