Implant Conductor Assembly RF Field Redirection

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Solution Overview

Problem

Surgically implanted conductors act as antennas during MRI procedures, leading to heating effects due to induced radio frequency currents, posing a patient safety risk, and existing shielding solutions are complex and costly to manufacture.

Innovation Solution

An implant conductor assembly with a field target conductor positioned adjacent to the electrode lead, offset from its longitudinal axis, to mutually couple and redirect electromagnetic fields away from the electrode lead, thereby minimizing induced radio frequency currents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a Faraday shield is used to surround and encapsulate the implant electrode lead, then the heating effects experienced by the lead are decreased, but the device complexity and manufacturing cost increase significantly

Engineering Contradiction:

Improveheating effectsVSAvoiddevice complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent extracts the shielding function from a complex Faraday shield structure and implements it through a simplified configuration using existing lead components and a simple outer conductor arrangement. This reduces device complexity while maintaining the ability to decrease heating effects during MRI procedures.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of surrounding and encapsulating the lead with a shield (traditional approach), the patent inverts the approach by positioning an outer conductor adjacent to and parallel with the lead, creating a controlled capacitive coupling that actively manages RF field interaction. This inversion simplifies the structure from a complex enclosure to a simple adjacent component arrangement.

Inventive Principle:

Principle #13The other way round (Inversion)

2Object-affected harmful factors

If a Faraday shield is used to surround and encapsulate the implant electrode lead, then the heating effects experienced by the lead are decreased, but the manufacturing cost increases

Engineering Contradiction:

Improveheating effectsVSAvoidmanufacturing cost

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent extracts the essential shielding function from the complex Faraday shield and implements it through simpler, more manufacturable components. The outer conductor can be formed as a simple structure rather than a complex encapsulating shield, significantly reducing manufacturing complexity and cost while maintaining effectiveness against RF heating.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs simpler conductor materials and structures that are easier and less expensive to manufacture. The outer conductor and lead configuration use standard medical-grade materials and simple geometric arrangements that are more cost-effective to produce than complex Faraday shield enclosures.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Length of moving object

If the implant conductor length is approximately equal to an odd integer multiple of half wavelength, then the conductor acts as an antenna concentrating RF fields, but this results in high temperatures at the electrode end

Engineering Contradiction:

Improveconductor lengthVSAvoidtemperature

Core Design Contradiction:

Length of moving objectVSTemperature

Solution Approach 1:

The patent introduces an outer conductor as an intermediary element that couples capacitively to the inner lead. This intermediary structure modifies the RF field distribution along the lead, preventing the concentration of fields at the electrode end that occurs when the lead acts as an antenna. The outer conductor acts as a mediator that redistributes the RF energy.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the electrical parameters of the lead assembly by adding the outer conductor, which alters the effective electrical length and impedance characteristics. This parameter change prevents the lead from resonating at problematic frequencies and reduces the temperature buildup that occurs with antenna-like behavior.

Inventive Principle:

Principle #35Parameter changes

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 reduces heating effects in the electrode lead by directing electromagnetic fields to the field target conductor, enhancing patient safety without the manufacturing complexities of traditional shielding methods.

Implementation Method 1

at least one field target conductor located adjacent to the electrode lead to mutually couple the field target conductor to the electrode lead, wherein the electrode lead acts to concentrate electromagnetic fields in the vicinity of the implant conductor assembly towards said at least one field target conductor

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS11077296B2Implant conductor assembly with improved radio frequency properties

Publication Date: 2021.08.03 SALUDA MEDICAL PTY LTD

AI summary

In one aspect the invention provides an implant conductor lead assembly which includes an electrode lead, and at least one field target conductor. The field target conductor(s) is located adjacent to the electrode lead to mutually couple the field target conductor to the electrode lead. The electrode lead acts to concentrate electromagnetic fields in the vicinity of the implant conductor assembly towards the field target conductor or conductors.