A Simulation Study on Selective Stimulation of C-Fiber Nerves for Chronic Pain Relief

Siyu He,Yu Yoshida,Wenwei Yu,Shao Ying Huang,Shozo Takamatsu,Kornkanok Tripanpitak

doi:10.1109/access.2020.2997964

Abstract

It has been reported that stimulating nociceptive unmyelinated C nerves (C) near the sarcolemma could induce the secretion of endogenous opioids that relieve chronic pain. However, a substantial concern remains: concomitant stimulation might cause acute pain to nociceptive myelinated Aδ nerves (Aδ), which generally have a lower activation threshold than the C. However, few studies have reported on C selectivity over Aδ (C-selectivity). In this study, the C and Aδ nerves were modeled using the Hodgkin-Huxley (HH) and McIntyre-Richardson-Grill (MRG) models, respectively. Two potential stimulation schemes, including bipolar square waves and burst modulated alternating current, together with a new stimulation scheme named inhibit-Aδ (i-Aδ) that inhibits the excitability of theAδ, were systematically investigated. Their stimuli were given to the C and Aδ nerves through point electrodes located near the nerve fibers. Simulation results revealed that i-Aδ presented the highest C-selectivity, which provides a basis for non-invasive effective chronic-pain relief.

Highlights

Chronic pain is one of the significant factors that reduce patients’ quality of life (QOL) because the condition is poorly understood and minimally treatable using existing therapies [1]
A survey showed that the retention rate of chronic pain increases with age [2]
Two main methods are available for chronic pain relief: 1) stimulation therapy and 2) drug therapy [3]

Summary

Introduction

Chronic pain is one of the significant factors that reduce patients’ quality of life (QOL) because the condition is poorly understood and minimally treatable using existing therapies [1]. A survey showed that the retention rate of chronic pain increases with age [2]. For countries facing rapidly aging populations, the treatment of chronic pain is an essential medical and even social issue [3]. Psychological therapy can improve pain treatment by facilitating positive subjective attitudes, such as treatment willingness and good interpersonal relationships [4]. Two main methods are available for chronic pain relief: 1) stimulation therapy (such as massage, physical therapy, and acupuncture) and 2) drug therapy [3].

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Discussion

Conclusion