Repetitive transcranial magnetic stimulation (rTMS) in experimentally induced and chronic neuropathic pain: a review.

UNLABELLED: Repetitive transcranial magnetic stimulation (rTMS) is an emerging technology that has been demonstrated to be useful in the treatment of depression and potentially useful in the management of several neurologic conditions. More recently, increasing attention has been directed at evaluating its efficacy in the treatment of patients with chronic neuropathic pain. We first discuss the literature examining the efficacy of rTMS in trials of experimentally induced acute pain as well as among patients with chronic pain. Examining frequency data obtained from the available literature, we attempted to identify some of the parameters of rTMS that appear to be related to its analgesic effects. An overview of the mechanisms underlying its potential analgesic role is discussed; generally, the influences of rTMS on cortical, and, indirectly, subcortical, neurons may reduce pain transmission ascending from spinothalamic tracts, thereby mitigating pain. Finally, we discuss some of the methodological issues and limitations of available studies and offer recommendations for further research. PERSPECTIVE: The authors provide a comprehensive review of rTMS use in the treatment of neuropathic pain in the literature available to date. Although the clinical usefulness of rTMS in pain has, as yet, to be determined, it offers insights into the pathophysiologic processes involved in the maintenance and exacerbation of chronic pain.