Helical Electrode Tapered Ends Nerve Stimulation
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Solution Overview
Problem
Current helical electrodes for nerve stimulation, such as those used in Vagus Nerve Stimulation (VNS), are inefficient in maximizing nerve fiber stimulation and conserving pulse generator battery power, with issues related to electric field distribution and recruitment of nerve fibers.
Innovation Solution
A helical electrode design with an insulative substrate and a conductor that encircles the nerve, featuring tapered end sections and a configuration that ensures a consistent electric field distribution, reducing variability in injected current by no more than 25% or 10% across similar axons, thereby improving stimulation efficacy and power conservation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional helical electrodes are used for nerve stimulation, then the electrode can be implanted around the nerve, but the electric field distribution is inconsistent causing high variability in injected current across different axons
Solution Approach 1:
The electrode conductor is designed with non-uniform properties - specifically tapered end sections where the width gradually changes. This local variation in conductor geometry creates a more uniform electric field distribution around the entire nerve circumference, compensating for the natural variability in axon positions and orientations. The tapered sections are strategically placed at the ends of the helical conductor to optimize field distribution in critical regions.
2Reliability
If the electrode is designed to maximize nerve fiber stimulation, then therapeutic effectiveness improves, but pulse generator battery power consumption increases
Solution Approach 1:
The electrode design optimizes the conductor dimensions - specifically the width and tapered section geometry - to achieve efficient electric field penetration and axon activation. By carefully selecting conductor width parameters and taper ratios, the electrode achieves effective nerve stimulation with lower current amplitudes, thereby reducing power consumption of the pulse generator while maintaining therapeutic effectiveness.
3Ease of manufacture
If the conductor width is uniform throughout, then manufacturing is simpler, but electric field distribution varies significantly across different axons
Solution Approach 1:
The conductor is designed with tapered end sections where the width gradually changes from the main body to a narrower tip. This local geometric variation is strategically implemented only at the ends of the helical conductor, while the central portion maintains uniform width for ease of manufacture. The tapered sections are designed with specific angle and length parameters that can be achieved through standard fabrication techniques while still providing the desired electric field uniformity.
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 electrode design enhances nerve fiber recruitment and therapeutic effectiveness while minimizing power consumption by concentrating the electric field and maintaining consistent current injection across the nerve circumference, leading to improved treatment outcomes with reduced side effects.
Implementation Method 1
The conductor produces an electric field in which an injected current in similar axons varies by no more than about 25%
Data Source
AI summary
A helical electrode for nerve stimulation includes an insulative helical substrate, having an inner surface, configured to wrap around a nerve. An electrical conductor is disposed upon the inner surface of the substrate. The conductor defines a helix of about one revolution and produces an electric field in which an injected current in similar axons varies by no more than about 25%. The conductor may include tapered end sections, which may be counter-tapered.