Expandable Stent Slide Lock Mechanism for Vascular Adaptability

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Solution Overview

Problem

Existing radially expandable and slidably engaged stents face mechanical and vasodynamic limitations, including deployment challenges in curved vasculature, resistance to natural movements like dilation and contortion, and increased stenosis due to neointimal growth, which affect the long-term patency and healing of vascular implants.

Innovation Solution

A stent design featuring a rotationally flexible backbone with a slide and lock mechanism, deformable struts, and a tubular structure that adapts to vasodynamic movements, incorporating biodegradable polymers for enhanced healing and reduced stenosis, while maintaining patency of the lumen.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a stent is designed with rigid structure to maintain lumen patency, then radial strength is improved, but flexibility to adapt to curved vasculature and vasodynamic movements deteriorates

Engineering Contradiction:
Improveradial strengthVSAvoidflexibility
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The stent is divided into multiple self-expanding segments or cells that can independently deform and adapt to curved vasculature while collectively maintaining radial strength through their coordinated structure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The stent employs a dynamic structure with movable joints and deformable struts that allow continuous adjustment to vasodynamic movements including dilation, contortion, and crush forces, while maintaining patency through active adaptation rather than rigid resistance

Inventive Principle:
Principle #15Dynamics

2Reliability

If a stent is designed to resist vasodynamic forces through rigid support, then lumen patency is maintained, but resistance to natural movements like dilation and contortion increases, causing stenosis

Engineering Contradiction:
Improvelumen patencyVSAvoidstenosis
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The stent structure incorporates dynamic elements that move with vasodynamic forces rather than resisting them, allowing the stent to expand and contract with natural vessel movements, thereby preventing stenosis while maintaining patency

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The stent material or structure changes its mechanical parameters in response to environmental conditions such as moisture absorption, transforming from a rigid delivery state to a flexible deployed state that adapts to physiological conditions

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If a stent uses biodegradable polymer material to promote healing, then adaptability to vasodynamics improves, but structural strength may deteriorate over time

Engineering Contradiction:
Improvevaso-adaptabilityVSAvoidstructural strength
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The biodegradable polymer undergoes controlled parameter changes including increased ductility and flexibility over time as it absorbs moisture, transforming from a structurally strong but less flexible material to a highly adaptable flexible support that better conforms to the evolving vessel wall

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The stent may combine biodegradable polymer with other materials or structural features that provide temporary structural strength during the degradation process, creating a composite structure that maintains both strength and adaptability throughout the healing period

Inventive Principle:
Principle #40Composite materials

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 stent effectively minimizes stenosis and adapts to natural vascular movements, promoting healing by transforming into a flexible support within the new vessel wall, reducing the risk of occlusions and improving long-term vascular health.

Implementation Method 1

Many devices are fabricated from a biodegradable polymer which may become substantially more ductile and flexible with the progression of time up to a point of water absorption equilibrium. As water is absorbed, the polymer material becomes bendable or ductile.

Methodology Applied
Scientific EffectWater absorption: Absorption (physical)

Implementation Method 2

The stent can include a plurality of deformable struts. The struts can be configured to deform, which can facilitate expansion of the stent.

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Data Source

PatentEP2988704B1Expandable deformable slide and lock stent
Publication Date: 2019.01.16 REVA MEDICAL INC
  • EP2988704B1 patent drawingFigure 1~2
  • EP2988704B1 patent drawingFigure 3
  • EP2988704B1 patent drawingFigure 4~6B

AI summary

Various embodiments of radially expandable stents are disclosed. In some embodiments, the stent includes a bond backbone, slot backbone, and a circumferentially extending rail connected with the bond backbone and slidably engaged with the slot backbone. In some embodiments, the stent includes annular support rings that define a plurality of cells. The annular rings can be joined with cross members. A rail member can be connected with one of the cross members and slidably engaged with another of the cross members. In various embodiments, the rail member includes a locking mechanism to facilitate one-way expansion of the stent.