Highlights
- •Neural recruitment order is consistent across spinal cord stimulation waveforms
- •Axon collateralization produces complex effects on activation thresholds
- •Gray matter cells have higher activation thresholds than primary afferents
Abstract
Spinal cord stimulation (SCS) is a popular neurostimulation therapy for severe chronic
pain. To improve stimulation efficacy, multiple modes are now used clinically, including
conventional, burst, and 10-kHz SCS. Clinical observations have produced speculation
that these modes target different neural elements and/or work via distinct mechanisms
of action. However, in humans, these hypotheses cannot be conclusively answered via
experimental methods. Therefore, we utilized computational modeling to assess the
response of primary afferents, interneurons, and projection neurons to conventional,
burst, and 10-kHz SCS. We found that local cell thresholds were always higher than
afferent thresholds, arguing against direct recruitment of these local cells. Furthermore,
although we observed relative threshold differences between conventional, burst, and
10-kHz SCS, the recruitment order was the same. Finally, contrary to previous reports,
axon collateralization produced complex changes in activation thresholds of primary
afferents. These results motivate future work to contextualize clinical observations
across SCS paradigms.
Perspective
This article presents the first computational modeling study to investigate neural
recruitment during conventional, burst, and 10-kilohertz spinal cord stimulation for
chronic pain within a single modeling framework. The results provide insight into
these treatments’ unknown mechanisms of action and offer context to interpreting clinical
observations.
Key words
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Article info
Publication history
Published online: September 25, 2021
Accepted:
September 11,
2021
Received in revised form:
September 9,
2021
Received:
May 5,
2021
Footnotes
Conflicts of Interest: SFL has equity in Hologram Consultants, LLC, is a member of the scientific advisory board for Abbott Neuromodulation, and receives research support from Medtronic, Inc SFL also holds stock options, received research support, and serves on the scientific advisory board of Presidio Medical, Inc All other authors declare no conflicts of interest.
Editor: Dr. G. Gebhart
Identification
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© 2021 by United States Association for the Study of Pain, Inc.
