Pulsed radiofrequency of suprascapular nerve for chronic shoulder pain: a randomized double-blind active placebo-controlled study.

BACKGROUND:  The suprascapular nerve block is frequently implemented to treat chronic shoulder pain. Although effective the nerve blockade provides only a short-term relief, and more compelling apaproaches have been investigated. Pulsed radiofrequency (pRF) has been anecdotally reported as safe and reliable method. However, formal efficacy study has not been published. Ostensibly evidence-based validation of a new method is necessary for both scholastic and practical purposes.

METHODS:  This study was designed as a randomized active placebo-control double-blind trial. Because of encountered difficulties in recruitment and high rate of dropout, the study was redesigned as to allow a smaller sample size and statistical analyses were performed utilizing the last observation carry forward method. Lidocaine injections alone or with combination of the pRF were performed. Participants were followed up during 6 months, and multiple subjective and objective outcome variables were recorded.

RESULTS:  Thirteen of 22 participants completed 6 months follow-up. Dropout rate was higher in the lidocaine group. A significant linear trend (P < 0.05) for improvement on the numeric rating scale, Shoulder Pain and Disability Index and Constant-Murley score was observed in the pRF group, but not in the lidocaine group. Patients in the pRF group were on average more satisfied than the lidocaine group at 1 month (P = 0.041) and at 3 months (P = 0.035).

DISCUSSION:  Considering limitations of the study design and statistics, it seems plausible to attribute better results in the pRF group to unique properties of this physical modality.