Spinal Cord Stimulation: Mechanisms of Action

Spinal cord stimulation (SCS) has been used in managing chronic pain conditions that are refractory to current pharmacotherapies. However, conventional SCS has often been associated with suboptimal efficacy and short-lived therapeutic effects. It is important to further improve the clinical efficacy of SCS by enhancing our understanding of its mechanisms of action (MOAs). Here, we review research on MOA in the past decade (2006–2016) and highlight important findings regarding the biological basis by which different paradigms of SCS may produce pain inhibition. In addition, we discuss future research directions. The potential mechanisms and neuronal substrates that may underlie the paresthesia-free pain inhibition by the novel kilohertz high-frequency SCS are further reviewed in more detail. Additionally, we describe the recently developed methods and rationales of recording electrically evoked compound action potential as an in situ electrophysiological measure to provide diagnostic and prognostic indications for chronic pain sufferers and to evaluate SCS.