Deep Transcranial Magnetic Stimulation: A Promising Drug-Free Treatment Modality in the Treatment of Chronic Low Back Pain.

Transcranial Magnetic Stimulation (rTMS) utilizes MRI-strength magnetic pulses outside the cranium to stimulate the brain to a depth of approximately 1 cm. The technique was approved by the US Food and Drug Administration (FDA) for the treatment of Major Depressive Disorder (MDD) in 2008. In 2013 the Brainsway Deep Transcranial Magnetic Stimulation (dTMS) device, which has the potential for cranial penetration up to 5 cm received FDA clearance for pharmacotherapy and psychotherapy resistant MDD. The mechanism of action of dTMS in MDD is not completely understood. However, its clinical efficacy is proven.' The effect of dTMS on the brain has been studied since 1985 in clinical trials and has been demonstrated as an effective treatment modality for refractory depressive symptoms. The mechanism of action of dTMS is thought to be mediated by increased connectivity between the dorsolateral prefrontal cortex (DLPFC) and the thalamus and reduced subgenual cingulate to caudate connectivity. These brain areas are believed to be responsible for modulating mood. Chronic pain is often accompanied by MDD. Specifically, chronic low back pain is highly prevalent and accompanied by significant disability.2 Low back pain is defined as chronic when the pain is continuous for more than three months. The current chronic pain treatment algorithm includes judicious use of non pharmacological interventions like physical therapy, chiropractic adjustments, therapeutic massage, or acupuncture combined with pharmacological interventions that utilize non-narcotic or narcotic oral medications, spinal/paraspinal injections and, in selected cases, surgery. In patients who fail this extensive algorithm for chronic pain management and are left with significant morbidity and disability, coincident MDD frequently becomes refractory to therapy. Two illustrative examples of chronic low back pain patients with medically refractory MDD treated successfully using dTMS are presented here to discuss the potential therapeutic benefits for both MDD and chronic low back pain in this setting.