Stent With Interlocking Segments For Tortuous Vessel Conformability

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Solution Overview

Problem

Balloon expandable stents are prone to permanent deformation in high-motion environments due to their inflexibility and lack of elasticity, limiting their ability to conform to tortuous vessels and withstand longitudinal compression and bending loads.

Innovation Solution

The stent design features interconnected axial segments with interlocking joints that maintain engagement during delivery and disengage during radial expansion, allowing for longitudinal and circumferential movement, providing resistance to mechanical loads and preventing jamming, while minimizing tissue interaction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If balloon expandable stents are used to provide greater radial force and circumferential compression resistance, then radial support performance is improved, but longitudinal flexibility and ability to conform to tortuous vessels deteriorate

Engineering Contradiction:
Improveradial forceVSAvoidlongitudinal flexibility
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The stent is divided into multiple axially-spaced segments that are coupled together by interlocking joints. Each segment can move independently relative to adjacent segments, allowing the stent to flex and conform to tortuous vessels while maintaining radial support through the coupled structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The interlocking joints between segments are designed to allow relative movement between segments in response to longitudinal compression and bending loads. This dynamic capability enables the stent to adapt to vessel motion and tortuosity while maintaining structural integrity and radial support.

Inventive Principle:
Principle #15Dynamics

2Strength

If balloon expandable stents are used to provide greater radial force, then circumferential compression resistance is improved, but inflexibility and lack of elasticity increase

Engineering Contradiction:
Improvecircumferential compression resistanceVSAvoidelasticity
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

By segmenting the stent structure, each individual segment can deform elastically in response to bending and compression loads, while the overall stent maintains circumferential compression resistance through the coupled segments. The segmentation allows localized flexibility without compromising global structural strength.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The interlocking joints are designed with specific geometric parameters that allow controlled relative movement between segments. This enables the stent to exhibit elastic behavior under physiological loads while maintaining the radial force and circumferential compression resistance provided by the balloon expandable structure.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If stent segments are coupled together to maintain structural integrity, then radial support is improved, but ability to accommodate high-level motion and bending loads deteriorates

Engineering Contradiction:
Improvestructural integrityVSAvoidmotion accommodation
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The interlocking joints are designed to allow dynamic relative movement between segments in response to bending and motion loads. This enables the stent to accommodate high-level motion in tortuous vessels like the SFA while maintaining structural integrity through the coupled segment architecture.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The segmented structure allows each segment to move independently relative to adjacent segments, accommodating bending and motion loads. The interlocking joints maintain structural integrity by keeping segments coupled during delivery and deployment, while allowing controlled relative movement during physiological operation.

Inventive Principle:
Principle #1Segmentation

4Manufacturing precision

If interlocking joints are designed to maintain engagement during delivery, then stent positioning accuracy is improved, but complexity of the coupling structure increases

Engineering Contradiction:
Improvestent positioning accuracyVSAvoidcoupling structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The coupling structure is divided into discrete interlocking joints between segments, each with simple engagement features. This segmentation allows the complex function of maintaining positioning accuracy to be achieved through multiple simple, repeatable joint designs rather than a single complex coupling mechanism.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The interlocking joints are designed to automatically engage and maintain coupling between segments during delivery and deployment without requiring additional actuation or control mechanisms. The joints self-maintain the coupled state throughout the delivery process, ensuring positioning accuracy while minimizing system complexity.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3315100B1Stent with segments capable of uncoupling during expansion
Publication Date: 2021.04.28 COOK MEDICAL TECHNOLOGIES LLC
  • EP3315100B1 patent drawingFigure 1~2
  • EP3315100B1 patent drawingFigure 3~4
  • EP3315100B1 patent drawingFigure 5

AI summary

Examples of a stent are provided where the stent has interlocking joints removably coupling adjacent axial stent segments. Mating elements forming the interlocking joints maintain circumferential and axial engagement when the stent is in the radially compressed configuration, for example, during tracking of the stent to a treatment site of a body vessel, and become disengaged during radial expansion of the stent. The length of mating elements may be sized as large as the strut width. When disengaged, the disconnected the axial stent segments remain discrete stent structures separated from one another along the point of treatment.