Analgesic Effects of Repetitive Transcranial Magnetic Stimulation at Different Stimulus Parameters for Neuropathic Pain: A Randomized Study

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. Key words: High frequency, repetitive transcranial magnetic stimulation, neuropathic pain, single stimulation, multiple stimulation, meta-analysis

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Added value of multiple versus single sessions of repetitive transcranial magnetic stimulation in predicting motor cortex stimulation efficacy for refractory neuropathic pain

Journal of Neurosurgery ◽

10.3171/2017.12.jns171333 ◽

2019 ◽

Vol 130 (5) ◽

pp. 1750-1761 ◽

Cited By ~ 4

Author(s):

Benjamin Pommier ◽

Charles Quesada ◽

Camille Fauchon ◽

Christophe Nuti ◽

François Vassal ◽

...

Keyword(s):

Neuropathic Pain ◽

Transcranial Magnetic Stimulation ◽

Pain Relief ◽

Motor Cortex ◽

Magnetic Stimulation ◽

Repetitive Transcranial Magnetic Stimulation ◽

Motor Cortex Stimulation ◽

Single Session ◽

Analgesic Effects

OBJECTIVESelection criteria for offering patients motor cortex stimulation (MCS) for refractory neuropathic pain are a critical topic of research. A single session of repetitive transcranial magnetic stimulation (rTMS) has been advocated for selecting MCS candidates, but it has a low negative predictive value. Here the authors investigated whether multiple rTMS sessions would more accurately predict MCS efficacy.METHODSPatients included in this longitudinal study could access MCS after at least four rTMS sessions performed 3–4 weeks apart. The positive (PPV) and negative (NPV) predictive values of the four rTMS sessions and the correlation between the analgesic effects of the two treatments were assessed.RESULTSTwelve MCS patients underwent an average of 15.9 rTMS sessions prior to surgery; nine of the patients were rTMS responders. Postoperative follow-up was 57.8 ± 15.6 months (mean ± standard deviation). Mean percentage of pain relief (%R) was 21% and 40% after the first and fourth rTMS sessions, respectively. The corresponding mean durations of pain relief were respectively 2.4 and 12.9 days. A cumulative effect of the rTMS sessions was observed on both %R and duration of pain relief (p < 0.01). The %R value obtained with MCS was 35% after 6 months and 43% at the last follow-up. Both the PPV and NPV of rTMS were 100% after the fourth rTMS session (p = 0.0045). A significant correlation was found between %R or duration of pain relief after the fourth rTMS session and %R at the last MCS follow-up (R2 = 0.83, p = 0.0003).CONCLUSIONSFour rTMS sessions predicted MCS efficacy better than a single session in neuropathic pain patients. Taking into account the cumulative effects of rTMS, the authors found a high-level correlation between the analgesic effects of rTMS and MCS.

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