MRI Lead Conductor with Polymer Coils for Torque and Heating

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Implantable medical device leads face challenges in torque transmission and resistance to magnetic resonance imaging (MRI) fields, which can cause heating and damage due to inadequate conductor designs and material properties.

Innovation Solution

The integration of polymer coils coiled coaxially with conductive coils in medical device leads, optimizing coil pitch and diameter to enhance torque transmission and minimize MRI-induced heating, using materials like expanded polytetrafluoroethylene (ePTFE) and polyether ether ketone (PEEK) for improved mechanical strength and biocompatibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a helically coiled conductor is used to provide torque transmission, then torque transmitting capacity is improved, but the conductor becomes more susceptible to MRI-induced heating

Engineering Contradiction:

Improvetorque transmitting capacityVSAvoidMRI-induced heating

Core Design Contradiction:

ForceVSObject-affected harmful factors

Solution Approach 1:

The patent uses a composite structure combining a helically coiled conductor with a polymer coil wrapped around it. The conductor provides torque transmission while the polymer coating protects against MRI-induced heating and provides mechanical support.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The polymer coil acts as an intermediary layer between the helically coiled conductor and the external MRI field. It provides a protective barrier that reduces the harmful effects of MRI fields while allowing the conductor to maintain its torque transmission function.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If coil pitch is reduced to minimize MRI heating, then heating is reduced, but torque transmission capacity decreases

Engineering Contradiction:

ImproveMRI heatingVSAvoidtorque transmitting capacity

Core Design Contradiction:

Object-affected harmful factorsVSForce

Solution Approach 1:

The polymer coil compensates for the reduced torque transmission capacity from the tighter coil pitch by providing additional mechanical support and maintaining the structural integrity of the conductor assembly, allowing the pitch to be optimized for MRI safety.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the physical parameters of the conductor assembly by introducing a polymer coating with specific mechanical properties that allow the coil pitch to be reduced without proportionally reducing torque transmission capacity, as the polymer structure compensates for the geometric changes.

Inventive Principle:

Principle #35Parameter changes

3Strength

If polymer coils are added to increase torque transmission, then mechanical strength is improved, but device complexity increases

Engineering Contradiction:

Improvemechanical strengthVSAvoidconductor configuration complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The polymer coil is merged with the helically coiled conductor in a single integrated structure. The polymer is applied directly to the conductor surface and coiled in unison, creating a unified assembly that provides enhanced mechanical strength without requiring separate, independent components.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The polymer coil serves multiple functions simultaneously: it provides mechanical strength and torque transmission support, protects the conductor from MRI-induced heating, maintains the coil pitch geometry, and provides a protective barrier. This multi-functionality reduces the need for additional separate components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

This configuration increases the torque transmitting capacity and tensile strength of the leads while reducing the impact of MRI fields on the device, ensuring reliable operation and longevity by maintaining proper spacing and pitch of coil turns.

Implementation Method 1

a helically coiled conductor electrically coupled to the at least one electrode, and one or more polymer coils. The helically coiled conductor includes a plurality of turns having a conductive coil pitch

Methodology Applied

Scientific EffectTorque transmission through helical coil structure: Helix

Implementation Method 2

The one or more polymer coils each include one or more polymer filars formed coaxially about the helically coiled conductor to provide at least about 25 μN·m of torque along a length of the medical device lead

Methodology Applied

Scientific EffectTorque generation through polymer coil structure: Helix

Implementation Method 3

The coil pitch and outer diameter are selected based on the filar diameter to minimize heating of the helically coiled conductor in the presence of an MRI field

Methodology Applied

Scientific EffectElectromagnetic induction heating: Electromagnetic Induction

Data Source

PatentUS8825181B2Lead conductor with pitch and torque control for MRI conditionally safe use

Publication Date: 2014.09.02 CARDIAC PACEMAKERS INC

AI summary

A medical device lead includes an insulated lead body including at least one electrode, a helically coiled conductor electrically coupled to the at least one electrode, and one or more polymer coils formed coaxially with the helically coiled conductor. The helically coiled conductor includes a plurality of turns having a conductive coil pitch and including one or more conductive filars each having a conductive filar diameter. The one or more polymer coils provide at least about 25 μN·m of torque transmitting capacity along a length of the medical device lead.