Shunt Valve Rotor Magnet Layout for MRI-Resistant Adjustment

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Solution Overview

Problem

Implantable fluid flow control devices, such as those used in treating hydrocephalus, face issues with inadvertent setting changes due to strong external magnetic fields, like those encountered in MRI procedures, and suffer from decreased magnetic coupling strength between implanted devices and external adjustment tools, leading to challenges in adjusting pressure settings optimally.

Innovation Solution

The design incorporates a rotor assembly with vertically oriented magnets and a mechanical stop mechanism that inhibits unintentional rotation in strong magnetic fields while allowing intentional adjustment, and utilizes angled magnetization to enhance magnetic coupling with external tools, ensuring robust magnetic interaction and resistance to field-induced changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a rotor assembly with horizontally aligned magnets is used for magnetic coupling with external adjustment tools, then magnetic coupling strength is improved, but resistance to inadvertent setting change in strong external magnetic fields deteriorates

Engineering Contradiction:

Improvemagnetic coupling strengthVSAvoidresistance to inadvertent setting change

Core Design Contradiction:

ForceVSReliability

Solution Approach 1:

The patent applies asymmetry by changing the magnet orientation from horizontal alignment to vertical alignment. This asymmetric reconfiguration creates a magnetic field geometry that is insensitive to strong external magnetic fields while maintaining effective coupling with external adjustment tools. The vertical orientation ensures that the magnetic moment is perpendicular to the direction of potential field-induced rotation, preventing inadvertent setting changes.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent changes the orientation parameter of the magnets from horizontal to vertical. This parameter change fundamentally alters the interaction between the rotor assembly's magnetic field and external magnetic fields. By adjusting this geometric parameter, the system achieves both strong magnetic coupling for intentional adjustment and resistance to field-induced rotation during MRI procedures.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If a rotor assembly with vertically oriented magnets is used to resist strong external magnetic fields, then resistance to inadvertent setting change is improved, but magnetic coupling strength with external tools deteriorates

Engineering Contradiction:

Improveresistance to inadvertent setting changeVSAvoidmagnetic coupling strength

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

The patent converts the potential harm of strong external magnetic fields into a benefit by using vertically oriented magnets. The vertical orientation causes the magnetic moment to be perpendicular to the direction of field-induced forces, effectively nullifying the harmful effect of external fields on rotor rotation. Simultaneously, the design maintains magnetic coupling capability through proper magnet strength and geometry selection.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If mechanical stops are added to inhibit unintentional rotation, then resistance to inadvertent setting change is improved, but device complexity increases

Engineering Contradiction:

Improveresistance to inadvertent setting changeVSAvoidmechanical stop mechanism

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical stop system with a magnetic field-based solution. Instead of using physical mechanical stops to prevent rotation, the vertically oriented magnets create a magnetic field configuration that inherently resists rotation from external magnetic fields. This substitution eliminates complex mechanical components while achieving the same protective function through magnetic field geometry.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 solution effectively minimizes inadvertent pressure setting changes during MRI procedures and improves the magnetic coupling strength between the implanted device and external tools, allowing for precise and reliable adjustment of fluid flow control devices.

Implementation Method 1

magnetic coupling strength between the implanted device and external tools

Methodology Applied

Scientific EffectMagnetic coupling: Magnetism

Implementation Method 2

ensuring robust magnetic interaction and resistance to field-induced changes

Methodology Applied

Scientific EffectMagnetic interaction: Magnetism

Implementation Method 3

resistance to inadvertent setting changes due to strong external magnetic fields

Methodology Applied

Scientific EffectMagnetic field resistance: Magnetism

Data Source

PatentUS11167117B2Fluid flow control devices, rotors and magnets with increased resistance to inadvertent setting change and improved accessory tool coupling

Publication Date: 2021.11.09 MEDTRONIC XOMED INC

AI summary

Implantable physiological shunt systems and related fluid flow control devices and accessories for use therewith. Devices, systems and methods relating to implantable medical fluid flow control devices, rotors and magnets with increased resistance to inadvertent setting changes. Devices, systems and methods relating implantable medical fluid flow control devices, rotors and magnets which provide improved magnetic coupling to fluid flow control device accessories such as adjustment tools.