Epidural Spinothalamic Tract Stimulation for Neuropathic Pain
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Solution Overview
Problem
Existing spinal cord stimulation techniques for treating chronic neuropathic pain face challenges in efficiently targeting the spinothalamic tract without inadvertently stimulating sensitive neural structures like dorsal root and ventral root nerve fibers, leading to side effects such as muscle contractions and pain.
Innovation Solution
Epidural application of electrical stimulation energy to the spinothalamic tract, with techniques to increase the activation threshold of sensitive neural structures relative to the spinothalamic tract, such as using tripolar electrode configurations, sub-threshold hyperpolarizing conditioning pulses, and time-varying electrical energy, to prevent inadvertent stimulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrical stimulation is applied epidurally to the spinothalamic tract, then chronic neuropathic pain is treated, but sensitive neural structures (dorsal root and ventral root nerve fibers) may be inadvertently stimulated causing side effects
Solution Approach 1:
The patent applies different electrical stimulation parameters to different spatial locations: higher amplitude stimulation is directed at the spinothalamic tract for pain relief, while lower amplitude or inhibitory stimulation is applied to dorsal root and ventral root nerve fibers to prevent side effects. This spatial differentiation of stimulation quality resolves the contradiction by treating the target effectively while protecting sensitive structures.
Solution Approach 2:
The patent changes electrical stimulation parameters (amplitude, pulse width, frequency) based on the target neural structure. By adjusting these parameters, the system can selectively activate the spinothalamic tract for analgesia while keeping stimulation below the threshold or using inhibitory patterns for adjacent sensitive nerve fibers, thereby eliminating harmful side effects while maintaining therapeutic benefit.
2Reliability
If subdural stimulation of the spinothalamic tract is used, then pain signals are inhibited, but surgical complexity and risk increase
Solution Approach 1:
The patent uses the epidural space as an intermediary location that provides access to the spinothalamic tract without requiring direct subdural placement. By positioning electrodes in the epidural space and using appropriate stimulation parameters, the system achieves spinothalamic tract modulation with the simplified epidural surgical approach, avoiding the complexity and risks of subdural implantation while maintaining therapeutic efficacy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively treats chronic neuropathic pain by targeting the spinothalamic tract while minimizing stimulation of sensitive neural structures, reducing side effects and maintaining therapeutic efficacy.
Implementation Method 1
electrical stimulation energy conveyed to the electrodes creates an electrical field, which, when strong enough, depolarizes (or 'stimulates') the neural fibers within the spinal cord beyond a threshold level, thereby inducing the firing of action potentials
Implementation Method 2
sub-threshold hyperpolarizing conditioning pulses
Data Source
AI summary
A method for treating a patient suffering from chronic neuropathic pain, comprises epidurally applying electrical stimulation energy to a spinothalamic tract of the patient, thereby treating the chronic neuropathic pain. The method may further comprise increasing the activation threshold of a side-effect exhibiting neural structure relative to the activation threshold of the spinothalamic tract of the patient, wherein the electrical stimulation energy is applied to the spinothalamic tract of the patient while the activation threshold of the neural structure relative to the spinothalamic tract is increased, thereby treating the chronic neuropathic pain without stimulating the neural structure.