Extensible Medical Lead With Sigmoidal Conductors

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Solution Overview

Problem

Implantable medical leads used for neurostimulation systems face challenges in accommodating the stretching and relaxing of the human body, leading to mechanical stress and potential disconnection of electrodes, which affects the consistency and effectiveness of electrical stimulation.

Innovation Solution

The development of extensible implantable medical leads with sigmoidal conductors formed from polymeric materials that can stretch and relax by at least 10-50% while maintaining electrical insulation and connectivity, allowing for repeated extension and contraction without loss of function.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the lead is made rigid to maintain structural integrity, then manufacturing precision and electrode connection stability are improved, but the lead cannot accommodate body stretching and relaxing, leading to mechanical stress and potential disconnection

Engineering Contradiction:

Improveelectrode connection stabilityVSAvoidaccommodation of body movement

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The lead transitions from a rigid structure to a dynamic, extensible structure that can change its length in response to body movements. The lead is designed to extend and contract elastically to accommodate stretching and relaxing of body tissues, preventing mechanical stress and disconnection while maintaining electrode connection stability through its adaptive geometry.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The lead's physical parameters, specifically its length and cross-sectional dimensions, are designed to change elastically in response to applied forces. The lead can extend by at least 10-50% and return to its original configuration, allowing it to accommodate body movements while maintaining electrical connectivity and structural integrity.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If the lead is made extensible to accommodate body stretching, then adaptability to body movement is improved, but mechanical stress may cause disconnection of electrodes

Engineering Contradiction:

Improveaccommodation of body stretchingVSAvoidelectrode connectivity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The lead incorporates a sigmoidal (S-shaped) configuration that allows it to extend and contract while maintaining electrical connectivity. The curved, sigmoidal geometry enables the lead to absorb mechanical stress through deformation without compromising the electrical pathways, allowing extensibility up to 10-50% while preserving electrode connectivity and reliability.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Reliability

If the lead uses traditional rigid conductors, then electrical conductivity is maintained, but the lead cannot be repeated extension and contraction without loss of function

Engineering Contradiction:

Improveelectrical stimulation consistencyVSAvoidrepeated extension and contraction durability

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The lead uses a composite structure combining extensible polymeric materials with conductive elements arranged in a sigmoidal pattern. This composite design allows the lead to undergo repeated extension and contraction cycles (at least 10-50%) while maintaining electrical conductivity and functional integrity, preventing loss of stimulation capability over time.

Inventive Principle:

Principle #40Composite materials

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 extensible leads ensure consistent electrical stimulation across varying body positions by maintaining electrode connectivity and functionality, even when subjected to stretching and relaxing body movements, thereby enhancing the reliability and effectiveness of neurostimulation therapies.

Implementation Method 1

The lead body is formed of a polymeric material that is extensible between a first length and a second length

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS9192758B2Extensible implantable medical lead with sigmoidal conductors

Publication Date: 2015.11.24 MEDTRONIC INC

AI summary

An extensible implantable electrical lead includes a lead body having a proximal region and a distal region. The lead body is formed of a polymeric material that is extensible between a first length and a second length. A first plurality of electrical conductors are disposed within the lead body and extend between the proximal region and the distal region. The first plurality of electrical conductors are each electrically insulated and spaced apart from each other and form a side-by-side co-planar first sigmoidal pattern between the proximal region and the distal region.