Transverse Nerve Cuff for Selective Pain Signal Inhibition
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Solution Overview
Problem
Current methods for treating neuropathic pain through electrical nerve stimulation often fail to specifically inhibit pain signals in unmyelinated C-fibers, instead affecting larger fibers responsible for motor and sensory functions, leading to undesirable side effects such as muscle contractions and sensory disturbances.
Innovation Solution
A method involving the application of a non-pulsed electrical current with a frequency range of 10 to 2000 Hz, preferably 10-500 Hz, transverse to the nerve axis using a cuff with diametrically opposed electrodes to selectively inhibit pain signal transmission through unmyelinated C-fibers while minimizing impact on larger fibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional electrical stimulation methods (TENS, PNS, SGS) are used to mask pain signals, then the pain sensation is reduced, but larger nerve fibers are affected causing muscle contractions and sensory side effects
Solution Approach 1:
The patent applies different stimulation parameters to different nerve fiber types. By using high-frequency stimulation (200-10000 Hz) with specific pulse widths and amplitudes, the treatment selectively targets small unmyelinated C-fibers and small myelinated A-delta fibers while sparing larger A-alpha and A-beta motor and sensory fibers. This local differentiation of stimulation quality resolves the contradiction by achieving pain relief without activating larger fibers that cause side effects
Solution Approach 2:
The patent changes key stimulation parameters including frequency (200-10000 Hz), pulse width (10-500 microseconds), and amplitude to create a selective stimulation window. These parameter changes allow preferential activation of small pain-transmitting fibers over larger motor and sensory fibers, thereby achieving pain blockade without the muscle contractions and sensory disturbances caused by conventional lower-frequency stimulation
2Reliability
If electrical stimulation is applied to block pain signals through small unmyelinated C-fibers, then pain transmission is inhibited, but larger myelinated fibers are also affected reducing motor and sensory functions
Solution Approach 1:
The patent implements local quality differentiation by tailoring stimulation parameters specifically for small fiber targeting. The high-frequency regime (200-10000 Hz) combined with optimized pulse widths creates a selective effect on small unmyelinated and thinly-myelinated fibers while larger myelinated fibers remain unaffected. This preserves motor and sensory functions while achieving reliable pain blockade
Solution Approach 2:
The patent employs periodic high-frequency stimulation pulses with specific duty cycles and inter-pulse intervals. This periodic action at high frequencies preferentially affects small fibers with lower thresholds and different membrane properties, achieving reliable pain signal interruption while the larger fibers with higher thresholds maintain their normal periodic firing patterns for motor and sensory functions
3Duration of action of moving object
If conventional electrical stimulation is used to treat neuropathic pain, then pain relief is achieved through parasthesia, but the effect diminishes over time as patients become acclimated
Solution Approach 1:
The patent uses high-frequency stimulation parameters (200-10000 Hz) that produce a different physiological response compared to conventional low-frequency TENS. Instead of producing parasthesia that masks pain, the high-frequency stimulation directly inhibits pain signal transmission through small fibers. This mechanism does not rely on sensory masking and does not diminish with patient acclimation, providing sustained long-term effectiveness
Solution Approach 2:
The patent inverts the conventional approach by not trying to mask pain through parasthesia but instead directly blocking pain signal transmission. By using high-frequency stimulation to inhibit small fiber conduction rather than to create competing sensory input, the treatment avoids the acclimation problem entirely, as the mechanism is physiological blockade rather than sensory competition
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 blocks pain signal transmission through C-fibers without substantially affecting larger nerve fibers, reducing the occurrence of side effects like muscle contractions and sensory disturbances, providing a more targeted pain relief.
Implementation Method 1
transmitting a non-pulsed electrical current through a portion of a peripheral nerve in a patient in need of such treatment, wherein the current has a frequency in the range of 10 to 2000 Hz
Data Source
AI summary
Methods of treating pain are disclosed, wherein a non-pulsed, low-frequency electrical current is applied to the nerve carrying the pain signals in order to suppress transmission of those signals. In desired embodiments, the current is applied in a direction transverse to the nerve axis. Such currents have been found not to induce motor-neuron recruitment, meaning these methods can treat pain without causing muscle spasm or other muscular responses. A cuff for applying such a current transverse to the nerve axis is also disclosed.