MRI-Compatible Cochlear Implant Magnet Apparatus

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Solution Overview

Problem

Conventional cochlear implants are susceptible to demagnetization and torque-induced dislocation when exposed to MRI magnetic fields, requiring surgical removal and replacement, which is invasive and undesirable.

Innovation Solution

A cochlear implant design featuring a magnet apparatus with magnetic material particles packed in a case that allows for reorientation within the magnetic field, maintaining alignment and preventing demagnetization and torque, thus eliminating the need for surgical intervention during MRI procedures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a conventional disk-shaped magnet is used in the cochlear implant, then the magnet can provide sufficient magnetic field strength for positioning, but the magnet becomes susceptible to demagnetization and torque-induced dislocation when exposed to MRI magnetic fields

Engineering Contradiction:

Improvemagnetic field strengthVSAvoidmagnet stability during MRI

Core Design Contradiction:

ForceVSReliability

Solution Approach 1:

The magnet is divided into multiple smaller magnetic particles instead of using a single solid disk magnet. These particles are contained within a capsule and can rotate independently, allowing the magnetic field to be maintained while individual particles can reorient to MRI field directions, preventing demagnetization and torque-induced damage.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The magnetic particles are made movable within the capsule rather than being fixed in a rigid structure. This dynamic configuration allows the particles to rotate and align with the MRI magnetic field during scanning, eliminating the static torque problem that causes dislocation in conventional fixed magnets.

Inventive Principle:

Principle #15Dynamics

2Reliability

If the implant magnet is removed prior to MRI procedure and replaced afterward, then the implant can be protected from demagnetization and torque, but the patient requires invasive surgical intervention which carries tissue damage risks

Engineering Contradiction:

Improvemagnet protection during MRIVSAvoidsurgical intervention requirement

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The magnetic particles within the capsule automatically reorient themselves in response to the MRI magnetic field without external intervention. This self-adjusting mechanism protects the magnet from demagnetization and torque during MRI procedures, eliminating the need for surgical removal and replacement.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The magnet is pre-configured with rotatable particles contained within a protective capsule structure before implantation. This beforehand preparation allows the magnet to withstand MRI magnetic fields without damage, cushioning against the harmful effects of demagnetization and torque that would otherwise require surgical intervention.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If the magnetic particles are allowed to move freely within the capsule, then the magnet can reorient to align with MRI fields and prevent demagnetization, but the magnetic field uniformity and positioning accuracy may be compromised

Engineering Contradiction:

Improveresistance to demagnetizationVSAvoidmagnetic field alignment precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The magnet is segmented into multiple particles that can rotate independently within the capsule. This segmentation allows each particle to align with the MRI field while collectively maintaining the overall magnetic field strength and positioning accuracy through their combined effect.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The magnetic particles can change their orientation parameter in response to external magnetic fields. During normal operation, the particles maintain a configuration that provides accurate positioning, while during MRI scanning, they can reorient to align with the MRI field, thus adapting their parameters to different operational conditions.

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 design ensures that the cochlear implant magnet remains functional and securely positioned during MRI scans without the need for surgical intervention, reducing the risk of tissue damage and improving patient safety.

Implementation Method 1

The magnet apparatus includes a case with an internal volume, a divider that separates the internal volume into a plurality of sub-volumes, and respective pluralities of magnetic material particles packed within the sub-volumes in such a manner that adjacent magnetic material particles are in contact with one another and are also movable relative to one another

Methodology Applied

Scientific EffectMagnetic field interaction: Magnetic Field

Data Source

PatentUS10300276B2Cochlear implants having MRI-compatible magnet apparatus and associated methods

Publication Date: 2019.05.28 ADVANCED BIONICS AG

AI summary

A cochlear implant is disclosed including a cochlear lead, an antenna, a stimulation processor, a magnet apparatus, associated with the antenna, including a case, a divider, and a plurality of magnetic material particles that are movable relative to one another within sub-volumes defined by the divider.