EMG Needle Electrode with DLC Coating for Reduced Insertion Force
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Solution Overview
Problem
Current EMG needles face challenges in balancing stiffness and dimensions, leading to discomfort during insertion and potential damage to insulative coatings, which affects test results and requires frequent needle replacement.
Innovation Solution
A needle electrode with a conductive core coated in biocompatible diamond-like carbon (DLC) and a lubricious second coating, featuring a tapered tip with bevels and a hub for lead wire connection, designed to reduce insertion force and enhance signal quality while maintaining mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the needle diameter is increased to provide sufficient stiffness for accurate placement, then the stiffness is improved, but patient discomfort increases
Solution Approach 1:
The patent applies parameter changes by modifying the physical and chemical properties of the coating material. The DLC coating has superior mechanical properties including higher hardness, lower friction coefficient, and greater adhesion strength compared to conventional PTFE or parylene coatings. These parameter changes allow the needle to maintain sufficient stiffness with a smaller diameter, thereby reducing patient discomfort while preserving placement accuracy.
Solution Approach 2:
The patent uses composite materials by combining the conductive needle core with a diamond-like carbon (DLC) coating layer. This composite structure leverages the high stiffness and strength of the DLC material to reinforce the needle, enabling it to achieve the required mechanical rigidity without increasing the needle diameter, thus resolving the contradiction between stiffness and patient comfort.
2Reliability
If conventional insulative coatings (PTFE or parylene) are used, then the needle provides electrical insulation, but the coating friction increases insertion force and the coating erodes during repeated use
Solution Approach 1:
The patent fundamentally changes the material parameters of the insulative coating by using diamond-like carbon (DLC) instead of conventional PTFE or parylene. The DLC coating exhibits a significantly lower coefficient of friction, reduced erosion rate, and superior adhesion to the needle core. These parameter changes directly address the contradictions by reducing insertion force while enhancing coating durability and reliability for repeated use.
Solution Approach 2:
The patent applies local quality by optimizing the coating properties specifically at the needle surface where friction and erosion occur. The DLC coating provides localized improvement in friction reduction and wear resistance at the critical interface between the needle and tissue, while maintaining electrical insulation properties throughout the coating layer.
3Strength
If the insulative coating is made thicker to provide mechanical strength, then the coating durability is improved, but the insertion force increases due to higher friction
Solution Approach 1:
The patent changes the material parameters of the coating to DLC, which has inherently superior mechanical strength per unit thickness compared to conventional coatings. This allows the coating to be thinner while still providing adequate mechanical strength and durability. The lower friction coefficient of DLC simultaneously reduces insertion force, resolving the contradiction between coating strength and insertion ease.
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 solution provides improved patient comfort, easier and more accurate placement, and reduced insulative coating erosion, resulting in higher signal quality and prolonged needle usability.
Implementation Method 1
A needle electrode with a conductive core coated in biocompatible diamond-like carbon (DLC) and a lubricious second coating
Implementation Method 2
A needle electrode with a conductive core coated in biocompatible diamond-like carbon (DLC) and a lubricious second coating, featuring a tapered tip with bevels
Data Source
AI summary
An electrode configured for use in electromyography procedures including a shaft having a first end and a second end, where the shaft consists of a conductive material; an electrically insulative first coating configured to encase the conductive material; a tapered tip at the first end of the shaft, where the tip is angled and is formed by removing the first coating from a first portion of the shaft and exposing a first length of conductive material; and a hub positioned at the second end of the shaft, wherein the hub is positioned after removing the first coating from a second portion of the shaft and exposing a second length of conductive material, wherein the hub is configured to electrically couple a lead wire to the second length of conductive material at the second end.