Coiled Electrode Tether Force Inversion for Implantable Lead Insertion
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Solution Overview
Problem
Conventional implantable medical leads with flat or ring-type electrodes face challenges in achieving long-term fixation and intimate contact with target tissue, especially in muscles that move, leading to potential damage during insertion due to overt stretching of soft coiled electrodes.
Innovation Solution
An implantable medical lead assembly featuring a coiled electrode coupled with a tether line, where the tether line transfers a pulling force as a pushing force to the coiled electrode during implantation, minimizing stretching and ensuring secure insertion without damaging the electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional flat or ring-type electrodes are used, then the lead structure is simple, but long-term fixation and intimate contact with target tissue cannot be achieved
Solution Approach 1:
The patent employs a coiled electrode configuration instead of conventional flat or ring-type electrodes. The coiled structure provides conformability to curved tissue surfaces and enables self-fixation through its inherent elasticity, achieving reliable long-term fixation and intimate contact with target tissue while accommodating tissue movement.
Solution Approach 2:
The patent changes the physical parameters of the electrode by using a soft, pliable material with specific elastic properties. The coiled electrode is designed with controlled wire diameter, coil spacing, and overall dimensions to provide both flexibility for tissue conformity and sufficient structural integrity for stable fixation over time.
2Reliability
If soft coiled electrodes are used for intimate tissue contact, then tissue compatibility is improved, but overt stretching during insertion damages the electrode
Solution Approach 1:
The patent incorporates a delivery system that pre-positions the coiled electrode in a constrained, non-stretched configuration before insertion. The electrode is maintained in its native coiled shape during delivery, and the insertion mechanism ensures that the electrode is deployed without subjecting it to excessive tensile forces that would cause overt stretching or damage.
Solution Approach 2:
The patent uses a delivery catheter or lead body as an intermediary structure to protect the soft coiled electrode during insertion. The electrode is delivered through this protective sheath, which prevents external forces from directly stretching the electrode. The electrode is only exposed and allowed to expand into its functional coiled configuration after safe delivery to the target site.
3Ease of operation
If pulling force is applied to insert the electrode, then insertion is achieved, but the soft coiled electrode stretches excessively
Solution Approach 1:
The patent inverts the traditional insertion approach by using a push-based mechanism rather than pull-based insertion. The delivery system pushes the coiled electrode forward into the target tissue using controlled axial force, while the electrode's distal end is constrained to prevent backward pulling that would cause stretching. This reverse approach maintains electrode length while achieving secure insertion.
Solution Approach 2:
The patent separates the insertion function from the electrode itself by using a dedicated delivery system. The electrode is extracted from its protective delivery sheath at the target site, allowing it to expand into its functional coiled configuration only after insertion is complete. This separation enables insertion without stretching, as the electrode never experiences tensile loads during the insertion process.
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 effectively promotes the insertion of coiled electrodes into target tissue without overt stretching, maintaining electrode integrity and ensuring long-term fixation and intimate contact with moving tissues.
Implementation Method 1
a pulling force applied to the leading segment is transferred to the coiled electrode at a point proximal the distal end
Data Source
AI summary
Implantable lead assembly including a lead body, an elongated conductor, a coiled electrode, and a tether line. The lead body maintains the conductor. The electrode is coupled to the conductor, defining proximal and distal ends. The tether line defines a trailing segment and a leading segment terminating in a leading end. The tether line is coupled to the coiled electrode at a point proximal the distal end, and the leading end extends distal the distal end. With this configuration, a pulling force applied to the leading segment is transferred to the electrode at a point proximal the distal end as a pushing force, thereby minimizing an opportunity for overt stretching of the coiled electrode during implantation. The lead assembly can further include a needle connected to the tether line.