High frequency repetitive transcranial magnetic stimulation therapy for chronic neuropathic pain: A meta-analysis

Background: increasing evidence supports an analgesic effect of repetitive transcranial magnetic stimulation (rtms) for neuropathic pain (np). however,the optimal parameters of rtms (stimulation frequency and treatment sessions) for achieving long-term analgesic effects remain unknown. this study analyzed the current findings in the literature. objective: the aim of this study was to assess the optimal parameters of rtms for np,including the rtms sessions needed for inducing acute as well as long-term analgesic effects. study design: a meta-analysis of the analgesic effect of high frequency rtms (hf-rtms) for neuropathic patients. setting: this meta-analysis examined all studies involving the analgesic efficacy of hf-rtms for np. methods: pubmed,embase,and the cochrane library were searched for clinical studies of rtms treatment on np published before december 31,2014. crude standardized mean differences (smd) with 95% confidence interval (ci) were calculated for pain intensity after different treatment sessions (from 1 to 10) and follow-up of one or 2 months after rtms treatment using random effect models. results: twenty-five studies (including 32 trials and 589 patients) were selected for the metaanalysis according to the inclusion and exclusion criteria. all 3 hf-rtms treatments (5,10,and 20 hz) produced pain reduction,while there were no differences between them,with the maximal pain reduction found after one and 5 sessions of rtms treatment. further,this significant analgesic effect remained forone month after 5 sessions of rtms treatment. limitations: there are limitations of this meta-analysis. for example,the long-term analgesic effects of different hf-rtms and low frequency (lf) rtms sessions,including the single session of rtms on different np of varying origins have yet not been evaluated; the full degree of pain relief is still unclear for many rtms studies. conclusions: hf-rtms stimulation on primary motor cortex is effective in relieving pain in np patients. although 5 sessions of rtms treatment produced a maximal analgesic effect and may be maintained for at least one month,further large-scale and well-controlled trials are needed to determine if this enhanced effect is specific to certain types of np such as post-stroke related central np. © 2015,american society of interventional pain physicians. all rights reserved.