A prospective study to evaluate the role of repetitive trans-cranial magnetic stimulation in treatment of chronic low back pain

Abstract

Introduction: Chronic Low Back Pain (CLBP) is a disabling musculoskeletal condition with a high prevalence in developing and developed countries. There are many treatment modalities but none of them provides a satisfactory and consistent cure. Recently focus has shifted to neuromodulation to cure chronic pains. The U.S. Food and Drug Administration (FDA) approved the use of Repetitive TMS (rTMS) in the management of Pain in 2013. Since then, centres across the world have been using Transcranial Magnetic Stimulation (TMS) as a noninvasive modality for the treatment of various pain conditions. rTMS is a variation of TMS where stimulation is provided in sessions to create long-term excitation in the brain cortex. Evidence on the effectiveness of rTMS for CLBP is scarce due to limited rigorous clinical trials. This study is the first of its kind undertaken in India to critically analyze the role of rTMS in the treatment of CLBP. Materials & Methods: In this single institutional prospective, single-blind study, we enrolled 40 patients of CLBP sharing similar clinical profiles. They were divided into a test group and a sham group. In the test group patients were given rTMS in addition to conventional treatment while in the sham group, patients were taken through the procedure of rTMS without actually being administered it. A figure-of-eight-shaped coil was used focusing on the Left M1 area and Dorsolateral prefrontal cortex to administer the rTMS by a trained physician. Visual Analogue Scores (VAS) were noted before and after the procedure. Each patient was continuously monitored during the procedure for any side effects. Subsequently, they were interviewed and followed up for 6 months. At the end of 6 months, data was compiled and conclusions were drawn. Result: In our study, we found that 90 per cent of patients in the test group reported a reduction in VAS score by 30 per cent reduction while the remaining had a 20 per cent reduction in pain scores. 90 per cent of subjects in the sham group reported a marginal improvement in VAS score which can be attributed to the placebo effect. Most patients in the test group reported an improvement in quality of life at the end of six months. None of the patients suffered any untoward side effects during or after the procedure. Conclusion: Based on our study we conclude that rTMS is a safe procedure and it can be used as a modality in treating CLBP with satisfactory outcomes. Although the sample size was small, it is the first study of its kind undertaken in India to evaluate the role of rTMS-based neuromodulation in treating this chronic disabling condition. However, to be accepted as a standard of care for CLBP it will require further multi-institutional robust clinical trials with long-term follow-up.