The effect of repetitive transcranial magnetic stimulation on refractory neuropathic pain in spinal cord injury

Abstract

Objective: To investigate the analgesic effect of repetitive transcranial magnetic stimulation (rTMS) on intractable neuropathic pain in patients with spinal cord injury (SCI).

Design: A single center, prospective, randomized, double-blinded, controlled study.

Setting: SCI rehabilitation unit of university rehabilitation center.

Participants: Seventeen patients with SCI and chronic neuropathic pain who met the inclusion criteria recruited between April 2010 and January 2012.

Interventions: Ten daily treatment sessions of real or sham rTMS (30 trains of 10-Hz stimuli for a duration of 5 seconds; a total of 1500 pulses at intensity equal to 110% of the resting motor threshold) was applied over vertex using a figure-of-8-shaped coil.

Outcome measures: Pain was assessed with visual analog scale (VAS) at baseline and 10 days, 6 weeks and 6 months after the treatment. Patients' satisfactions obtained using a 5-point Likert scale at 6 months.

Results: Both real and sham rTMS provided a significant reduction in the VAS scores (real rTMS group, P = 0.004; sham rTMS group, P = 0.020). Post hoc analysis revealed the significant difference was at 10 days and 6 weeks compared to baseline in the real rTMS group and only at 10 days compared to baseline in the sham rTMS group. Comparison of VAS scores and patient satisfaction did not show any significant difference at each assessment point (P > 0.05).

Conclusion: Our results demonstrated analgesic effect of rTMS on intractable neuropathic pain in SCI was not superior to placebo. However, middle-term (over 6 weeks) pain relief by rTMS is encouraging and suggests the need for future studies with a larger sample size.

Keywords: Pain; Repetitive transcranial magnetic stimulation; Spinal cord injury.

Figures

Figure 1

Changes in the VAS scores over time. There was a significant reduction in the VAS scores for both groups (real rTMS group, P = 0.004; sham rTMS group, P = 0.020). (*Post hoc analysis showed the reduction was significant at 10 days and 6 weeks compared to baseline in the real rTMS group [1A] and was significant only at 10 days compared to baseline in the sham rTMS group [1B]). rTMS, repetitive transcranial magnetic stimulation; VAS, visual analogue scale.