Repetitive Transcranial Magnetic Stimulation in Chronic Pain: A Meta-analysis

BACKGROUND: In this meta-analysis, we explore the role of repetitive transcranial magnetic stimulation (rTMS), a noninvasive neuromodulation technique in the treatment of chronic pain. METHODS: Studies comparing rTMS and conventional treatment for chronic pain were searched. The comparison was made for decrease in the pain scores with and without (sham) the use of rTMS after a follow-up interval of 4–8 weeks. All reported pain scores were converted into a common scale ranging from “0” (no pain) to “10” (worst pain). RESULTS: Nine trials with 183 patients in each of the groups were included in the analysis. The decrease in pain scores with rTMS was 1.12 (95% confidence interval [CI] being 1.46–0.78) (fixed effects, I(2) = 0%, P < 0.001) and in sham-rTMS was 0.28 (95% CI being 0.49–0.07) (Fixed effects, I(2) = 0, P = 0.01). The pooled mean drop in pain scores with rTMS therapy was higher by 0.79 (95% CI being 0.26–1.33) (fixed effects, I(2) = 0, P < 0.01). The duration and frequency of rTMS were highly variable across trials. Publication bias was unlikely (Egger's test, X-intercept = 0.13, P = 0.75). CONCLUSIONS: Use of rTMS improves the efficacy of conventional medical treatment in chronic pain patients. This treatment is not associated with any direct adverse effects. However, the duration and frequency of rTMS therapy is presently highly variable and needs standardization.