Intra-spinal microstimulation may alleviate chronic pain after spinal cord injury

Med Hypotheses, 2017 · DOI: 10.1016/j.mehy.2017.05.028 · Published: July 1, 2017

Spinal Cord Injury Neurology Pain Management

Simple Explanation

Chronic pain following spinal cord injury (SCI) is difficult to treat. This paper proposes that directly stimulating the spinal cord with a technique called intraspinal microstimulation (ISMS) may help alleviate this pain. The idea is that ISMS can normalize the over-excitability of nerve cells in the spinal cord's dorsal horn, which is thought to be a key area involved in generating pain after SCI. By carefully adjusting the stimulation parameters, ISMS could block pain signals from reaching the brain and restore the spinal cord's ability to inhibit pain.

Study Duration

Not specified

Participants

Not specified

Evidence Level

Level 5, Hypothesis

Key Findings

1
ISMS may induce frequency-dependent conduction block on axons of afferent sensory neurons, in the spinothalamic tract and Lissauer’s tract.
2
ISMS may also facilitate primary afferent depolarization that elicits presynaptic inhibition of incoming afferent inputs.
3
ISMS may directly induce inhibitory postsynaptic potentials in dorsal horn neurons, and trigger the release of endogenous inhibitory neurotransmitters, opioids and serotonin to inhibit postsynaptic neurons

Research Summary

Chronic pain after spinal cord injury (SCI) is a debilitating condition often resistant to current treatments. The authors hypothesize that intraspinal microstimulation (ISMS) may alleviate SCI pain by normalizing dorsal horn neuronal hyperexcitability. ISMS may work by blocking pain signals, facilitating inhibition of afferent inputs, and restoring segmental pain inhibition. Repetitive ISMS may help the dorsal horn regain normal pain processing. The hypothesis can be tested using electrophysiological and behavioral approaches in preclinical models. ISMS could offer a novel approach to treat SCI pain by directly targeting pain generators in the spinal cord.

Practical Implications

Novel Pain Therapy

ISMS may provide a new approach to treat SCI pain, especially at-level and below-level pain, when other treatments are ineffective.

Targeted Pain Relief

By directly targeting pain generators in the spinal cord, ISMS may offer more selective and effective pain relief compared to other neuromodulatory techniques.

Reduced Side Effects

ISMS may require lower stimulus intensity and energy consumption than epidural spinal cord stimulation, potentially reducing side effects.

Study Limitations

1
The evolving nature of SCI pain and variability in patient responses may limit the applicability of ISMS.
2
The dependence on spinal neuronal hyperexcitability as the primary mechanism of SCI pain may not account for all cases.
3
Technical challenges in electrode design, implantation, and the risk of infection may pose limitations to ISMS implementation.

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