Abstract
Motor cortex stimulation (MCS) using surgically implanted epidural electrodes was shown to produce pain relief in patients with chronic neuropathic pain. Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive approach that could be used as a preoperative tool to predict MCS outcome and also could serve as a therapeutic procedure in itself to treat pain disorders. Use of transcranial magnetic stimulation for management of neuropathic pain has been suggested based on the success of electrical stimulation of the cerebral cortex in relieving pain This therapeutic application requires repeated rTMS sessions every day for 1 or 2 weeks, followed by a maintenance protocol. The most studied cortical target is the precentral cortex, but other targets, especially the dorsolateral prefrontal cortex, could be of interest. The analgesic effects of cortical stimulation relate to the activation of various circuits modulating neural activities in remote structures, such as the thalamus, the limbic cortex, the insula, or descending inhibitory controls. rTMS might influence the affective-emotional component of neuropathic pain by means of cingulate and orbitofrontal activation, which leads to descending inhibition of pain impulses by activation of the upper brainstem. Motor cortex rTMS as a therapeutic option in patients with neuropathic pain is supported by various sets of results with a high level of evidence statistically, but whose significance remains to be proven clinically. Also, the procedure needs to be further optimized before being fully integrated into clinical practice.
