The clinical effects of repetitive transcranial magnetic stimulation with deep TMS H system for the treatment of intractable pain in lower extremities

Abstract

   Background: In a previous study, we revealed that repetitive transcranial magnetic stimulation (rTMS)using figure-8 shaped coil could relieve neuropathic pain (NP) less effectively in the lower extremities than the upper ones. We speculated that it depended on the depth of the targeted primary cortex (M1).Deep rTMS is a novel development that can stimulate deep neuronal regions effectively, termed the H-coil. In this study, we compared the clinical effects for NP patients in their lower extremities between rTMS with H-coil, rTMS with figure-8 shaped coil and sham stimulation.
   Methods: This was a randomized, double-blind, three-way crossover trial.12 NP patients in their lower extremities received three types of stimulations for 5 consecutive days with 17 days follow-up. In each rTMS session, 5-Hz rTMS to M1 corresponding to the painful lower extremity was administered. Outcome measures were visual analogue scale (VAS) and Japanese version of the short form of the McGill pain questionnaire 2 (SF-MPQ2).
   Results: H-coil rTMS, compared with the sham, showed significant pain improvement soon and one hour after rTMS in VAS (p<0.001). On the other hand, pain improvement after rTMS with figure-8 shaped coil was not significant in VAS. Both types of rTMS didn't show significant pain improvement in SF-MPQ2.No serious adverse events were observed.
   Conclusions: Our findings demonstrated that rTMS with H-coil could be tolerable and provide modest pain relief in NP patients in their lower extremities.