Tubular Nerve Electrodes for Reversible High-Frequency Conduction Block
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Solution Overview
Problem
Existing methods for inhibiting action potential conduction in nerves, such as those used for treating respiratory obstructive diseases like COPD, suffer from inefficiencies, adverse effects, and safety concerns, including tissue damage, discomfort, and incomplete blockage due to high electrical field strength, frequency, and non-selective nerve fiber blocking.
Innovation Solution
A system using a tubular hosting element with electrodes applying alternating current signals at frequencies between 5-100 kHz, amplitudes of 1-20 mA, and phase durations of 1-200 µs, with balanced cathodic and anodic phases, to inhibit action potential conduction safely and selectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If direct current is applied to create a localized electric field for reversible conduction block, then nerve conduction is blocked, but tissue damage occurs due to changes in pH, temperature, or electrode material by electrolysis
Solution Approach 1:
The patent changes the electrical parameter from direct current to alternating current at high frequency (2-100 kHz). This parameter change allows the system to achieve nerve conduction block through a different mechanism (sodium channel inactivation) that does not rely on electrolysis, thereby preventing tissue damage while maintaining reliable reversible blocking
Solution Approach 2:
The patent substitutes the electrochemical mechanism (electrolysis) with an electrophysiological mechanism (sodium channel inactivation). By using high-frequency alternating current to repeatedly activate and inactivate sodium channels, the system achieves conduction block without the harmful electrochemical reactions that cause tissue damage
2Reliability
If high-frequency alternating current is used to activate sodium channels into refractory state, then action potential propagation is blocked, but axon classes with high excitation thresholds remain difficult to block
Solution Approach 1:
The patent employs dynamic parameter adjustment, allowing the frequency, amplitude, and pulse width of the alternating current to be optimized based on the specific nerve fiber type being targeted. This dynamic approach enables effective blocking across different axon classes (A, B, and C fibers) by adapting stimulation parameters to match the varying excitation thresholds of different fiber types
Solution Approach 2:
The patent utilizes a broad frequency range (2-100 kHz) and adjustable amplitude/pulse width parameters to match the diverse physiological properties of different axon classes. By changing these electrical parameters, the system can effectively block various fiber types including those with high excitation thresholds that resist standard high-frequency block
3Reliability
If high-frequency alternating current is applied, then nerve conduction is blocked, but onset and offset excitation phenomena occur causing discomfort and incomplete block
Solution Approach 1:
The patent uses periodic alternating current at high frequency to continuously activate and inactivate sodium channels. This periodic action maintains the nerve in a refractory state during stimulation, preventing the transient excitation that occurs with single-pulse or low-frequency methods. The continuous periodic stimulation ensures complete and stable block without onset or offset phenomena
Solution Approach 2:
The patent maintains continuous high-frequency alternating current application during the desired block period, ensuring uninterrupted sodium channel inactivation. This continuous action prevents the nerve from recovering excitability between pulses, eliminating the incomplete block and transient excitation seen with intermittent or low-frequency stimulation
4Reliability
If high electrical field strength and high frequency are used for HF block, then action potential block is achieved, but material or tissue damage occurs in chronic applications
Solution Approach 1:
The patent changes from the traditional high-frequency block parameters (which require high electrical field strength) to an optimized parameter set that achieves equivalent blocking efficacy at lower field strengths. By adjusting frequency, amplitude, and pulse width within the 2-100 kHz range, the system maintains reliable block while reducing the electrical stress that causes chronic tissue and electrode damage
5Duration of action of stationary object
If low frequency block is applied, then lasting blocking effect is achieved, but reversibility is poor and large sustained onset effect occurs
Solution Approach 1:
The patent uses periodic high-frequency alternating current that can be easily turned on and off. When activated, the periodic stimulation quickly induces sodium channel inactivation and produces reliable block. When deactivated, the nerve rapidly recovers excitability because no cumulative electrochemical changes occur. This periodic action provides both duration control and complete reversibility
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
The system effectively blocks nerve conduction with minimal adverse effects, allowing temporary inactivation of nerve activity and selective blocking, suitable for treating conditions like COPD and cardiac diseases, while minimizing onset and offset effects.
Implementation Method 1
The direct current causes a hyperpolarization of the nerve membrane, deactivating voltage-gated ion channels and resulting in blockage of action potential propagation
Implementation Method 2
The direct current causes a hyperpolarization of the nerve membrane, deactivating voltage-gated ion channels
Implementation Method 3
The HF block may initially activate sodium channels that then go into a refractory state, which may lead to a reduction in membrane excitability, blocking the propagation of action potentials
Data Source
Figure 1A~1B
Figure 1C
Figure 2~3
AI summary
The invention provides a system (100) for inhibiting conduction of an action potential (25) in a nerve (10), wherein the system (100) comprises an arrangement (200), wherein: the arrangement (200) comprises a tubular hosting element (211) configured for at least partially surrounding the nerve (10), wherein the tubular hosting element (211) comprises a plurality of electrodes (220); the system (100) is configured to apply in a treatment mode of the system (100) an electrical signal (20) via at least part of the plurality of electrodes (220), wherein the following applies: the electrical signal (20) has a frequency (FE) selected from the range of 5 - 50 kHz; the electrical signal (20) has an amplitude (AE) selected from the range of 2-10 mA; the electrical signal (20) comprises a plurality of phases (30), wherein the plurality of phases (30) comprises alternating cathodic phases (31) and anodic phases (32), wherein each phase (30) has a duration TP individually selected from the range of 5 - 60 µs; and the electrical signal (20) comprises a therapeutic period, wherein FE, AE and TP are constant during the therapeutic period, and wherein during the therapeutic period the electrical signal (20) has a charge per time (CPT) selected from the range of 1.0 - 7.0 mC/s, wherein CPT = FE*AE*TP.