Magnetically Expandable Medical Device for Vessel Wall Apposition

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Solution Overview

Problem

Conventional implantable medical devices face challenges in maintaining a constant force against vessel walls, leading to potential leakage, migration, and unnatural forces on the vessel, which can result in restenosis and increased foreign material volume.

Innovation Solution

A magnetically expandable medical device utilizing magnetic repulsion to maintain the expanded state against the vessel wall, eliminating the need for mechanical force and allowing for greater flexibility and compatibility with vessel curvature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mechanical force is used to hold the device against the vessel wall, then the device can maintain a constant force for good patency, but the device requires larger volume of material and has increased profile

Engineering Contradiction:

Improveconstant force applicationVSAvoiddevice volume

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent replaces mechanical force-generating structures with magnetic elements that generate repulsive forces. The magnetic elements are embedded in the body member and interact with an external magnet system to provide the constant force needed for vessel wall apposition, eliminating the need for bulky mechanical spring or balloon structures.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical state and properties of the device by incorporating magnetic materials with specific magnetic moments. The magnetic elements can be permanently magnetized or temporarily magnetized, allowing the device to transition from a passive mechanical structure to an actively force-generating structure with controlled magnetic field interactions.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If mechanical force is used to hold the device against the vessel wall, then the device can maintain constant force, but the device structure imparts unnatural forces on the vessel wall leading to restenosis

Engineering Contradiction:

Improveconstant force applicationVSAvoidrestenosis risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The magnetic repulsion force provides a more physiological and distributed pressure profile compared to concentrated mechanical forces from springs or balloons. The force is generated throughout the body member structure rather than at discrete mechanical contact points, reducing stress concentrations that could trigger restenosis.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The magnetic force distribution can be controlled by adjusting the magnetic moment orientation and strength of individual elements, allowing optimization of the force profile to match physiological vessel wall stress patterns and minimize harmful localized pressures.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If mechanical force structures are used, then the device can maintain constant force, but the device has increased foreign material volume implanted

Engineering Contradiction:

Improveconstant force applicationVSAvoidforeign material volume

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The magnetic elements replace large volumes of mechanical force-generating materials such as spring steel, shape memory alloys, or balloon polymers. The magnetic elements can achieve the same force-generating function with significantly less material volume, reducing the overall foreign body burden in the patient.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Strength

If the device is made with sufficient structural strength to generate mechanical force, then constant force can be maintained, but the device profile increases and compressibility for delivery decreases

Engineering Contradiction:

Improvestructural strengthVSAvoiddevice profile

Core Design Contradiction:

StrengthVSLength of moving object

Solution Approach 1:

The magnetic elements provide force generation without requiring the thick-walled, high-strength mechanical structures needed for spring or balloon-based systems. This allows the device to maintain a low profile suitable for delivery through catheters while still generating adequate force against the vessel wall through magnetic interaction.

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

The magnetic device provides a constant, flexible seal with minimal disruption to the vessel, reducing the risk of restenosis and foreign material volume, making it suitable for delicate vessels like cerebral vessels.

Implementation Method 1

makes use of constant magnetic repulsion to keep the body member of the device in its expanded state against the vessel wall

Methodology Applied

Scientific EffectMagnetic repulsion: Magnetism

Data Source

PatentEP2932940B1Magnetically expandable medical device

Publication Date: 2021.08.11 COOK MEDICAL TECHNOLOGIES LLC

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AI summary

An implantable medical device (10) includes a body member (12), which may be a graft tube, is provided with a plurality of magnetic elements (20) disposed in opposing sets (22-28) and arranged with opposing magnetic polarities. The magnetic elements (22) create repulsive forces which open the implantable medical device (10), providing an alternative to a conventional implantable medical device which is kept open by mechanical forces.