P160. Transcranial magnetic stimulation in chronic neuropathic pain – A prospective study of 45 patients

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Introduction Chronic neuropathic disorders remain difficult to treat. Analgesic medication often achieve only an insufficient effect, therefore other non-pharmacological treatment has to be considered. One option for management of intractable pain is stimulation of the motor cortex by implantation of an epidural electrode. This effect of invasive stimulation could be replaced by transcranial magnetic stimulation. Objectives The objective of the study was to observe the pain reducing effect of non-invasive transcranial magnetic stimulation (rTMS) in patients suffering from different types of chronic neuropathic pain. Materials and methods The study was prospective. We included patients suffering from chronic pain syndroms, such chronic facial pain, poststroke pain, phantom pain and FBSS. The corresponding primary motor cortex has been stimulated with high-frequent, repetitive transcranial magnetic stimulation (rTMS). Stimulation was daily repeated. The individual pain level was assessed by the visual analogue scale (VAS) and documented daily for three weeks. The first follow up was done after 6 weeks. Results We included 45 patients (24 female/21 male) between 31 and 78 years of age. The follow up was done at least after six weeks, further intervals were determined individually with a maximum follow up time of 4 years. A pain reduction in terms of a decrease in the VAS scale was obtained in 58% of patients over all groups, ranging from 2 to 8 points on VAS with a mean value of 3,6. Regarding the etiology of pain we observe a responding rate of 72% in the facial pain group, 40% in the poststroke pain group, 25% in the FBSS group and no responding in the phantom pain group. The pain reduction occurred with a delay between 4 days and 3 weeks, and showed a long term effect up to 10 months. Conclusion Non-invasive transcranial magnetic stimulation seems to be applicable for neuropathic pain syndromes. In chronic facial pain we could observe a higher responding rate than in any other chronic pain syndrome. Pain reduction has a long term effect, which outlast the stimulation period.