Atraumatic Stent Crowns with Radial Force Reducing Tips

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Solution Overview

Problem

Conventional stents with rigid flanges or flares can cause tissue perforations during peristalsis, leading to pain and serious complications such as infection and hemorrhage due to excessive radial force exerted on the vessel wall.

Innovation Solution

The development of stents with atraumatic crowns featuring a circumferential row of crown tips made from radial force reducing materials, such as silicone, which are softer and more flexible than the stent's wire segments, reducing the risk of tissue damage by adapting to the tissue environment while maintaining an open pathway.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If rigid flanges or flares are used to prevent stent migration, then stent stability is improved, but tissue damage and perforation risk increase

Engineering Contradiction:

Improvestent stabilityVSAvoidtissue damage

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The crown tips are made of a softer material (radial force reducing material) than the stent body, creating a local quality difference. This allows the stent body to remain rigid for stability while the crown tips are compliant to reduce tissue damage during peristalsis.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The stent combines two different materials: a rigid material for the stent body (providing structural support and stability) and a softer radial force reducing material for the crown tips (reducing tissue trauma). This composite approach resolves the contradiction between stability and tissue protection.

Inventive Principle:

Principle #40Composite materials

2Stability of the object's composition

If flanges are set to larger expanded diameter to secure stent position, then stent stability is improved, but radial force per unit area against vessel wall increases causing damage

Engineering Contradiction:

Improvestent position stabilityVSAvoidradial force

Core Design Contradiction:

Stability of the object's compositionVSForce

Solution Approach 1:

The crown tips use a softer material that reduces radial force transmission to the tissue, while the stent body maintains its structural integrity for position stability. This local material differentiation allows large diameter flanges without excessive radial force.

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If conventional rigid crown tips are used, then manufacturing simplicity is maintained, but tissue perforation and pain occur during peristalsis

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidtissue perforation

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The stent uses composite materials with the crown tips made from radial force reducing material attached to the stent body. This provides tissue protection while remaining manufacturable through processes like bonding or crimping the softer material onto the stent framework.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS9610179B2Atraumatic stent crowns

Publication Date: 2017.04.04 COOK MEDICAL TECHNOLOGIES LLC

AI summary

Methods and apparatuses of atraumatic stents with likely reduced rates of tissue perforation are provided. The stents of the invention have crowns with crown tips having apexes made of a radial force reducing material. The apexes are soft and flexible and reduce the radial force at the crown relative to the stent body allowing the crowns to collapse with greater ease compared to the central portion of the stent.