Endoluminal Prosthesis With Undulating Nitinol Rings

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Solution Overview

Problem

Existing endoluminal prostheses face challenges in providing sufficient columnar strength while maintaining flexibility for placement in tortuous vessels and ensuring a secure seal to prevent aneurysm pressurization, particularly during deployment and cyclical loading.

Innovation Solution

A tubular graft with annular support members featuring an undulating or sinusoidal patterned wire ring, constructed of Nitinol, which provides radial compressibility and flexibility, allowing for conforming engagement with the vessel wall and preventing excessive leakage, while maintaining a low profile for delivery through small catheters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If expandable ring members are used to provide columnar strength and sealing engagement, then the prosthesis can seal against the vessel wall and provide structural support, but the device flexibility and radial compressibility are reduced

Engineering Contradiction:

Improvecolumnar strengthVSAvoiddevice flexibility

Core Design Contradiction:

StrengthVSAdaptability or versatility

Solution Approach 1:

The support structure is divided into multiple discrete annular rings spaced along the graft length, with each ring providing localized support and sealing. The rings are connected through the graft material rather than rigid connectors, allowing independent movement and flexibility while maintaining overall structural integrity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The graft material itself serves as a flexible membrane that connects the rigid annular support rings, allowing the structure to bend and conform to tortuous vessels while the rings provide necessary columnar strength and radial sealing force

Inventive Principle:

Principle #30Flexible shells and thin films

2Ease of operation

If the prosthesis is designed with sufficient radial compressibility for delivery through small catheters, then minimally invasive placement is enabled, but the structural support and sealing capability are compromised

Engineering Contradiction:

Improveradial compressibilityVSAvoidsealing capability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The annular rings are designed with dynamic characteristics that allow them to be compressed radially during delivery through the catheter, then expand to their full diameter upon deployment to provide adequate sealing force and structural support against the vessel wall

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The prosthesis is pre-compressed into a low-profile configuration suitable for catheter delivery, with the annular rings folded or compressed radially. During deployment, the rings automatically expand to their functional diameter, establishing sealing engagement with the vessel wall without requiring additional expansion mechanisms

Inventive Principle:

Principle #10Preliminary action

3Strength

If the support structure is made rigid to provide adequate columnar strength, then structural integrity is improved, but the ability to conform to tortuous vessels and achieve sealing engagement is reduced

Engineering Contradiction:

Improvecolumnar strengthVSAvoidconforming ability

Core Design Contradiction:

StrengthVSShape

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The annular rings are designed with curved, undulating, or sinusoidal patterns rather than perfect circles, allowing the structure to better conform to the natural curvature and tortuosity of blood vessels while maintaining radial sealing force and columnar strength

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 enhances columnar strength and flexibility, ensuring a secure seal within the vessel to prevent aneurysm pressurization and rupture, while allowing for effective deployment and radial compressibility for minimally invasive procedures.

Implementation Method 1

The annular support members each comprise an annular expandable member formed by an undulating or sinusoidal patterned wire ring... constructed of Nitinol

Methodology Applied

Scientific EffectSuperelasticity: Pseudoelasticity

Data Source

PatentUS8702787B2Endoluminal prosthesis

Publication Date: 2014.04.22 MEDTRONIC VASCULAR INC

AI summary

An endoluminal prosthesis is provided that includes a tubular graft and an expandable annular support structure. The annular support structure is coupled to the tubular graft so that the graft and support structure, in combination, provide columnar support while maintaining prosthesis flexibility. The prosthesis has sufficient strength and durability to withstand loads applied during deployment and sufficient flexibility to permit implant in a sealing arrangement within a tortuous body lumen. An embodiment according to the invention provides a plurality of annular structures with staggered, longitudinally overlapping apices of undulating structures. One embodiment relates to tubular grafts for endoluminal placement within a body lumen, including blood vessels, and for the treatment of abdominal and other aneurysms.