Magnetic Centering Tool for Implantable Valve Adjustment

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Solution Overview

Problem

Adjustable implantable fluid flow control devices face challenges in accurately determining and adjusting valve settings due to weak magnetic coupling, especially at increased distances and in the presence of strong external magnetic fields, which can lead to inadvertent setting changes.

Innovation Solution

The development of centering and combined centering-indicator tools with a magnetic capsule that moves within a cavity to center itself over the valve magnet, allowing for precise alignment and indication of valve settings, even through tissue, using a tool magnet with configurations such as vertical polarity and Halbach arrays to enhance magnetic field strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the distance between the implanted valve magnet and the external tool increases, then the accessibility for adjustment is improved, but the magnetic coupling strength decreases leading to inaccurate setting determinations

Engineering Contradiction:

Improveaccessibility for adjustmentVSAvoidsetting determination accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

A magnetic centering tool with a magnetized needle acts as an intermediary device between the external adjustment tool and the implanted valve magnet. The needle centers itself within a target circle when positioned over the valve magnet, providing a visual indicator that ensures proper alignment and maintains strong magnetic coupling even when the overall system distance is increased for better accessibility.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Force

If the magnetic field strength is increased to improve coupling through tissue, then the magnetic coupling is strengthened, but inadvertent setting changes may occur due to alignment with strong external fields

Engineering Contradiction:

Improvemagnetic coupling strengthVSAvoidresistance to inadvertent setting changes

Core Design Contradiction:

ForceVSReliability

Solution Approach 1:

The valve magnet incorporates a specific geometric configuration (such as a multipole arrangement) that creates a localized magnetic field pattern with a distinct magnetic center. This local field structure allows for strong coupling with properly aligned tools while providing inherent resistance to misalignment from external magnetic fields, as the field strength varies significantly with position and orientation.

Inventive Principle:

Principle #3Local quality

3Reliability

If mechanical stops or magnet configurations are added to resist strong nearby magnetic fields, then resistance to inadvertent setting changes is improved, but deliberate adjustment becomes more difficult without accurate alignment

Engineering Contradiction:

Improveresistance to inadvertent setting changesVSAvoiddeliberate adjustment ease

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The magnetic centering tool serves as a mediator that facilitates deliberate adjustment by providing visual feedback through the centered needle indicator. This ensures accurate alignment between the adjustment tool and valve magnet before adjustment occurs, making the adjustment process easier and more reliable while maintaining resistance to inadvertent changes from external fields.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Measurement precision

If the magnetic capsule is allowed to move freely within the cavity to center itself, then alignment precision is improved, but the device complexity increases

Engineering Contradiction:

Improvemagnetic center alignment precisionVSAvoidtool internal mechanism complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The magnetic capsule containing the needle is allowed to move freely within the cavity and automatically centers itself through magnetic attraction to the valve magnet. This self-centering mechanism achieves precise alignment without requiring complex external positioning mechanisms, actuators, or control systems, thereby maintaining device simplicity while improving alignment precision.

Inventive Principle:

Principle #25Self-service

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

These tools enable accurate and deliberate adjustment of valve settings by aligning with the magnetic center of the valve, reducing the risk of inadvertent changes and improving coupling, even in challenging environments like MRI procedures.

Implementation Method 1

a tool magnet with configurations such as vertical polarity and Halbach arrays to enhance magnetic field strength

Methodology Applied

Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

magnetic capsule that moves within a cavity to center itself over the valve magnet

Methodology Applied

Scientific EffectMagnetic coupling: Magnetism

Data Source

PatentEP2968869B1Device for finding the center and reading the setting of an implantable medical device

Publication Date: 2019.05.01 MEDTRONIC XOMED INC

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Figure 3~3A
Figure 3B

AI summary

A centering tool and a combined centering-indicator tool (50) for finding the magnetic center and indicating the setting of an implantable adjustable valve (20). The centering and combined centering-indicator tools include a magnetic capsule (80) movable within a cavity (70) to a target (81) located on the tool when the magnetic capsule is centered over magnet of an adjustable valve.