Stent Helical Struts Axial Overlap Biodegradable Link Prevention

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Solution Overview

Problem

Stents with high flexibility, such as helical shaped struts, can deform easily under external forces, leading to connection section overlap and reduced diameter, which hinders blood flow due to insufficient distribution of connection sections along the radial direction.

Innovation Solution

A stent design featuring linear struts with helical portions and link portions that include first and second connection sections connected by a biodegradable material, where the connection sections are positioned to overlap along the axial direction, preventing overlap when deformed, and maintaining structural integrity until the biodegradable material degrades.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If helical shaped struts are used to improve flexibility, then the stent can better follow the shape of the body lumen, but the struts become easily deformed by external forces

Engineering Contradiction:
ImproveflexibilityVSAvoidresistance to deformation
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The strut is divided into multiple helical portions connected by link portions. Each helical portion maintains flexibility while the link portions provide connection points that resist deformation. The segmentation allows the stent to bend and conform to body lumens while maintaining overall structural integrity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The link portion uses a biodegradable material that connects the helical portions. This composite structure combines the flexibility of helical metal portions with the bonding properties of the biodegradable material, creating a structure that is both flexible and resistant to deformation during the healing process.

Inventive Principle:
Principle #40Composite materials

2Device complexity

If connection sections are positioned to overlap along the radial direction to simplify structure, then manufacturing is easier, but the stent diameter is reduced and blood flow is hindered

Engineering Contradiction:
Improvestructural simplicityVSAvoidstent diameter
Core Design Contradiction:
Device complexityVSVolume of moving object

Solution Approach 1:

The connection sections are arranged to overlap along the axial direction instead of the radial direction. This dimensional change in the overlap arrangement maintains the simplified connection structure while preventing radial thickening that would reduce stent diameter and hinder blood flow.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

Instead of having connection sections overlap in the radial direction (conventional approach), the invention inverts the overlap direction to the axial direction. This inversion resolves the contradiction by maintaining structural simplicity while preserving adequate stent diameter for blood flow.

Inventive Principle:
Principle #13The other way round (Inversion)

3Reliability

If connection sections are distributed to prevent overlapping under deformation, then blood flow is maintained, but the distribution pattern becomes complex and manufacturing becomes difficult

Engineering Contradiction:
Improveprevention of connection section overlapVSAvoidmanufacturing difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The connection sections are pre-positioned and fixed in their respective helical portions before the biodegradable material degrades. This preliminary positioning ensures that when deformation occurs, the connection sections are already in the correct positions to prevent overlapping, maintaining reliability without requiring complex real-time adjustment mechanisms.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the positional parameters of the connection sections along the axial direction, creating a specific distribution pattern that prevents overlap under deformation. This parameter change (axial positioning) achieves the reliability goal while maintaining manufacturability through a systematic arrangement rather than complex asymmetric positioning.

Inventive Principle:
Principle #35Parameter changes

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 maintains high strength and flexibility, preventing connection section overlap and ensuring smooth blood flow by allowing the stent to follow the body lumen's shape without reducing its diameter, even under compression and bending forces.

Implementation Method 1

a biodegradable material configured to connect the first connection section and the second connection section by being interposed between the first connection section and the second connection section

Methodology Applied
Scientific EffectBiodegradation: Decomposition (biological)

Data Source

PatentEP3295902B1stent
Publication Date: 2019.08.21 TERUMO KK
  • EP3295902B1 patent drawingFigure 1
  • EP3295902B1 patent drawingFigure 2
  • EP3295902B1 patent drawingFigure 3A~3B

AI summary

A stent is disclosed, which is capable of preventing connection sections from overlapping with each other in a radial direction when a force is applied inadvertently thereto by adjusting distribution of the connection sections with respect to a direction of helix of the strut. A link portion of the stent includes connection sections provided integrally with one helical portion and other helical portions adjacent to each other, and disposed in positions overlapped with each other at least partly along an axial direction of a cylindrical shape in a state of opposing to each other, and a biodegradable material connecting connection sections by being interposed between the connection sections.