Effect of deep intramuscular stimulation and transcranial magnetic stimulation on neurophysiological biomarkers in chronic myofascial pain syndrome

Abstract

Objective. The aim was to assess the neuromodulation techniques effects (repetitive transcranial magnetic stimulation [rTMS] and deep intramuscular stimulation therapy [DIMST]) on pain intensity, peripheral, and neurophysiological biomarkers chronic myofascial pain syndrome (MPS) patients. Design. Randomized, double blind, factorial design, and controlled placebo-sham clinical trial. Setting. Clinical trial in the Laboratory of Pain and Neuromodulation at Hospital de Clı’nicas de Porto Alegre (NCT02381171). Subjects. We recruited women aged between 19- and 75-year old, with MPS diagnosis. Methods. Patients were randomized into four groups: rTMS1DIMST, rTMS1sham-DIMST, shamrTMS1DIMST, sham-rTMS1sham-DIMST; and received 10 sessions for 20 minutes each one (rTMS and DIMST). Pain was assessed by visual analogue scale (VAS); neurophysiological parameters were assessed by transcranial magnetic stimulation; biochemical parameters were: BDNF, S100b, lactate dehydrogenase, inflammatory (TNF-α, IL6, and IL10), and oxidative stress parameters. Results. We observed the pain relief assessed by VAS immediately assessed before and after the intervention (P< 0.05, F(1,3)5 3.494 and F(1,3)5 4.656, respectively); in the sham-rTMS1DIMST group and both three active groups in relation to sham-rTMS1sham- DIMST group, respectively. There was an increase in the MEP after rTMS1sham-DIMST (P< 0.05). However, there was no change in all-peripheral parameters analyzed across the treatment (P> 0.05). Conclusion. Our findings add additional evidence about rTMS and DIMST in relieving pain in MPS patients without synergistic effect. No peripheral biomarkers reflected the analgesic effect of both techniques; including those related to cellular damage. Additionally, one neurophysiological parameter (increased MEP amplitude) needs to be investigated.