Robot-guided neuronavigated rTMS as an alternative therapy for central (neuropathic) pain: Clinical experience and long-term follow-up

Background: Repetitive transcranial magnetic stimulation (rTMS) appears as a useful tool to alleviate neuropathic pain but only few data are available for the long-term benefit of this treatment. Methods: Here we report the effects of rTMS sessions, considered as a possible therapy for pain relief after a failure of different medications in patients with central (neuropathic) pain. We review here the prospectively collected data of the first forty patients treated as follow: 20 Hz stimulation delivered over the contralateral primary motor cortex (M1), each 3-4 weeks. Results: A total of 440 rTMS sessions was collected (mean sessions number: 11, range: 1-37, follow-up 312 days on average, maximum 2.8 years). After four sessions, nine patients (22.5%) discontinued rTMS because of a lack of efficiency (<10% pain-relief). The other 31 patients (77.5%) had a cumulative effect across sessions leading to a mean pain relief of 41% for a duration of 15.6 days. A correlation was observed between pain relief in the first session and long-term pain relief (R = 0.649. p = 5.6*10(-6)). Both intensity and duration of pain relief were significantly better for patients with persistent laser evoked potentials (LEPs, p = 0.049 and 0.0018). We did not observe any adverse-effects. Conclusion: These results suggest that repeated sessions of 20 Hz rTMS over M1 are interesting in clinical practice for the treatment of selected patients with central pain. Both the cumulative effects across the first sessions and the long duration of pain-relief should impact further randomized trials that are warranted to conclude formally on rTMS efficiency in central pain.