Overlapping mechanisms of epidural spinal cord stimulation for pain control and movement recovery

PURPOSE OF REVIEW: Spinal cord stimulation (SCS) for pain control and movement recovery have developed under parallel conceptual frameworks. SCS for pain has traditionally targeted the dorsal columns, while SCS for movement recovery has targeted the large-diameter afferent fibers near the dorsal root entry zone. We review the evidence to support these parallel mechanistic frameworks and explore potential mechanistic overlap between the two fields. RECENT FINDINGS: Recent advances in closed-loop stimulation for pain and dorsal root (DR) stimulation for movement recovery speak to the value of these parallel mechanistic models in each field. However, review of the devices, electrode placement, and stimulation parameters used in both fields reveals overlap in the doses of SCS considered effective in each. Furthermore, evidence from finite element modeling suggests overlapping recruitment of dorsal column and dorsal root fibers from both midline and lateral stimulation. SUMMARY: There is evidence to support overlapping mechanisms of SCS for pain and movement recovery. The implications of potential mechanistic overlap warrant further investigation.