Implantable Lead Conductor Interconnections Using Conductive Interposers

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Solution Overview

Problem

Existing implantable medical leads face challenges in creating secure and reliable electrical connections between small multi-strand conductor cables and electrodes, such as ring or multi-filar shock coil electrodes, while maintaining mechanical strength and adhering to industry standards, particularly due to the fragility of these connections and reliance on adhesives which can degrade over time.

Innovation Solution

The implementation of implantable leads with a lead body that includes longitudinally extending lumens for conductors, electrically conductive interposers, ring members, and axial support members to provide secure mechanical and electrical connections, reducing the need for adhesives and allowing for smaller lead sizes, enhanced axial reinforcement, and improved manufacturing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If stranded wire conductors are used to reduce lead body size, then lead body diameter is reduced, but the connection between conductor and electrode becomes fragile and difficult to make

Engineering Contradiction:

Improvelead body sizeVSAvoidconnection reliability

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

An electrically conductive interposer is introduced as an intermediary component between the stranded wire conductor and the electrode. The interposer has a first end coupled to the conductor and a second end forming an electrical connection with the electrode, thereby mediating the connection and improving reliability while maintaining reduced lead body size.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The lead assembly employs composite construction combining stranded wire conductors with electrically conductive interposers. This composite approach allows the stranded wire to provide flexibility and size reduction while the interposer provides robust electrical connection capability.

Inventive Principle:

Principle #40Composite materials

2Strength

If adhesive bonding is used to connect distal electrode to lead body, then additional axial strength is provided, but the connection may still fall short of industry standards and can degrade over time

Engineering Contradiction:

Improveaxial strengthVSAvoidconnection durability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent replaces adhesive bonding (chemical/mechanical system) with a direct electrical connection system using the electrically conductive interposer. This mechanical-electrical integration provides superior axial strength and long-term reliability while meeting or exceeding industry standards.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The connection assembly combines the electrically conductive interposer with the electrode and conductor in a composite structure that provides both electrical connectivity and mechanical strength, eliminating the need for separate adhesive bonding.

Inventive Principle:

Principle #40Composite materials

3Length of moving object

If small multi-strand conductor cables are used, then lead body size is reduced, but the connection becomes very difficult to make and fragile

Engineering Contradiction:

Improveconductor diameterVSAvoidconnection manufacturing difficulty

Core Design Contradiction:

Length of moving objectVSEase of manufacture

Solution Approach 1:

The electrically conductive interposer serves as a mediator that simplifies manufacturing by providing a standardized interface between the small multi-strand conductor and the electrode. The interposer can be crimped or otherwise mechanically attached to the conductor and then electrically connected to the electrode, making the manufacturing process more reliable.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Strength

If conventional conductor-electrode connections are used, then industry standards for axial strength may not be met, but adding more adhesive or reinforcement increases lead body size

Engineering Contradiction:

Improveaxial strengthVSAvoidlead body size

Core Design Contradiction:

StrengthVSVolume of moving object

Solution Approach 1:

The electrically conductive interposer creates a composite connection structure that simultaneously provides high axial strength and maintains compact dimensions. The interposer is designed to fit within the existing lead body architecture without requiring additional space, thus meeting industry standards without increasing lead body size.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS8055354B2Interconnections of implantable lead conductors and electrodes and reinforcement therefor

Publication Date: 2011.11.08 CARDIAC PACEMAKERS INC

AI summary

An implantable lead comprises a lead body extending from a lead proximal end portion to a lead distal end portion. The lead body includes one or more longitudinally extending lumens. A conductor is received in, and extends along, a lumen. In varying examples, the implantable lead further comprises a tubular electrode co-axial with, and overlying portions of, the lead body. In one example, a lumen wall is sized and shaped to urge an electrically conductive interposer coupled with the conductor toward an inner surface of the electrode. In another example, a ring member is disposed within a lumen and the conductor is drawn and coupled thereto. In yet another example, an electrically conductive connector couples a first and a second conductor via grooves or threads. In a further example, an axial support member couples a distal end electrode and the lead body. Methods associated with the foregoing are also discussed.