Implantable Lead Helical Conductor Eliminating Connector Failure
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Solution Overview
Problem
Conventional implantable medical leads face issues with reliability due to connector failures, increased tissue attachment, and difficulty in extraction, particularly in regions with exposed electrodes that facilitate tissue ingrowth, affecting both electrical performance and extraction processes.
Innovation Solution
The development of an implantable lead with a helically-wound conductor configuration and fluoropolymer insulation, featuring a multi-filar arrangement with uninsulated portions serving as electrodes, eliminating the need for connectors and minimizing tissue attachment while maintaining high tensile strength and flexibility, and incorporating features like passive or active fixation tips and therapeutic agent delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional transvenous defibrillator leads use a stranded wire with a discrete connector or junction between the conductor and electrode, then electrical energy can be conducted from the connector to the electrode, but reliability decreases due to connector interfaces serving as points of failure
Solution Approach 1:
The patent merges the conductor and electrode into a single continuous helically-wound structure, eliminating the discrete connector or junction that previously separated these components. The helical conductor extends continuously from the proximal connector region to the distal electrode region, removing the interface that served as a point of failure and thereby improving reliability.
Solution Approach 2:
The patent extracts and removes the discrete connector or junction component from the lead structure. By eliminating this separate component, the design removes the potential failure point while maintaining the necessary electrical connection through the continuous helical conductor.
2Ease of operation
If conventional leads use a discrete connector, then electrical connection can be established, but the lead diameter increases in the connector region, leading to increased tissue attachment and difficulty in extraction
Solution Approach 1:
The patent combines the conductor and electrode into a continuous helical structure that maintains a consistent diameter throughout its length. This eliminates the localized diameter increase that occurred in the connector region of conventional leads, reducing tissue attachment in that area and facilitating easier extraction when necessary.
Solution Approach 2:
Instead of having a discrete connector that increases diameter at a specific location, the patent inverts the approach by using a continuous helical conductor that maintains uniform diameter throughout, thereby inverting the diameter profile from non-uniform (with connector bulge) to uniform (without connector bulge).
3Reliability
If the electrode surface is exposed to allow contact with tissue, then electrical performance is improved, but tissue ingrowth and anchoring occur, making the lead difficult to extract
Solution Approach 1:
The patent applies different surface properties to different regions of the helical conductor. The distal portion of the helix that contacts tissue has a surface treatment or coating that prevents tissue ingrowth and anchoring, while maintaining adequate electrical contact. This local differentiation allows the lead to be extracted more easily without compromising electrical performance in the electrode region.
Data Source
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AI summary
A highly flexible implantable lead that offers improved flexibility, fatigue life and fatigue and abrasion resistance improved reliability, effective electrode tissue contact with a small diameter and low risk of tissue damage during extraction. In one embodiment the lead is provided with both defibrillation electrodes and pacing/sensing electrodes. For defibrillation/pacing leads, the lead diameter may be as small as six French or smaller. The construction utilizes helically wound conductors. For leads incorporating multiple separate conductors, many of the helically wound conductors are arranged in a multi-filar relationship. Preferably, each conductor is a length of wire that is uninsulated at about the middle of its length to create an electrode, wherein the conductor is folded in half at about the middle of the length to create first and second length segments that constitute parallel conductors.