Occipital nerve stimulation in fibromyalgia: a double-blind placebo-controlled pilot study with a six-month follow-up.
OBJECTIVE
The goal of this study is to evaluate the effectiveness of occipital nerve stimulation (ONS) as a surgical treatment for fibromyalgia in a placebo-controlled design.


MATERIALS AND METHODS
Eleven patients were selected based on the American College of Rheumatology-90 criteria and implanted with an occipital nerve trial-lead stimulator. Baseline scores for pain, mood, and fatigue were acquired, and patients were randomized in a ten-week double-blinded crossover design with placebo and effective subsensory threshold stimulation (no paresthesias). After finalizing the trial, nine patients were implanted permanently; evaluation was performed prior to surgery and at six months after surgery for pain, fatigue, and mood of the number of trigger points and overall morbidity.


RESULTS
Significant results were found during the trial for a decrease in pain intensity (39.74%) on visual analogue scale (VAS; p < 0.001) and pain catastrophizing scale (PCS) during effective stimulation. A total of 9/11 patients responded to trial treatment; however, in two patients, this might be a placebo effect, recognizable due to the study design. Six months after permanent implantation, pain intensity remained decreased (44.01%) on VAS (p < 0.05). Besides the VAS, significant changes were noted for PCS, fatigue (modified fatigue impact scale), the number of trigger points, and overall morbidity (fibromyalgia impact questionnaire). There were no serious adverse events.


CONCLUSIONS
Our data strongly suggest that ONS is beneficial in the treatment of fibromyalgia. The beneficial effects are stable at six months after permanent implantation. Subsensory threshold stimulation is feasible in designing a placebo-controlled trial.