Stent-Graft With Segmented Graft Layers For Flexibility

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Solution Overview

Problem

Conventional stent-graft assemblies lack flexibility due to direct attachment or encapsulation of graft layers, which restricts the movement of the stent structure and increases manufacturing complexity and cost.

Innovation Solution

A stent-graft assembly with inner and outer graft layers secured through openings in the stent structure, featuring unattached margins between attached areas and the stent edges, allowing relative movement between the graft layers and the stent, thereby enhancing flexibility and reducing manufacturing complexity and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If graft layers are directly attached to the stent structure, then structural integrity is improved, but flexibility deteriorates

Engineering Contradiction:

Improvestructural integrityVSAvoidflexibility

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The graft layers are segmented into attached portions and unattached margin portions. The attached portions are secured to the stent through openings to provide structural integrity, while the unattached margin portions remain free to move independently, enabling flexibility. This segmentation allows the stent-graft assembly to maintain both strength and flexibility simultaneously.

Inventive Principle:

Principle #1Segmentation

2Reliability

If graft layers are secured through manual suturing, then attachment reliability is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveattachment reliabilityVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The manual mechanical suturing process is replaced with a thermal bonding process. The graft layers are thermally bonded to each other through the stent openings using heat and pressure, eliminating the need for needles, thread, and manual knotting. This substitution maintains attachment reliability while dramatically simplifying manufacturing and reducing costs.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Stability of the object's composition

If graft layers are fully encapsulated, then structural stability is improved, but flexibility deteriorates

Engineering Contradiction:

Improvestructural stabilityVSAvoidflexibility

Core Design Contradiction:

Stability of the object's compositionVSEase of operation

Solution Approach 1:

Different portions of the graft layers have different qualities: the attached portions provide structural stability through thermal bonding, while the unattached margin portions provide flexibility by remaining free to move. This local differentiation of properties allows the stent-graft assembly to achieve both structural stability and flexibility simultaneously.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS8034096B2Stent-graft with graft to graft attachment

Publication Date: 2011.10.11 COOK MEDICAL TECHNOLOGIES LLC

AI summary

A stent-graft assembly is provided for a variety of medical treatments. The stent-graft assembly includes a stent disposed between an inner layer of graft material and an outer layer of graft material. The graft layers are effectively secured to the stent by attaching the graft layers together through openings in the structure of the stent. Relative movement between the graft layers and the stent is made possible by providing unattached margins between the attached areas of the graft layers and the edges of the stent openings.