Helical Stent with Segmented Retaining Part
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Solution Overview
Problem
Existing stents often migrate within the body and cause traumatic damage to surrounding tissues due to their design, which can lead to erosion and ineffective retention of the lumen in body cavities.
Innovation Solution
A stent design featuring a retaining part and an expandable part with a first configuration for insertion and a second configuration for placement, utilizing Shape Memory Alloys to conform to the body cavity's curvature, minimizing tissue contact, and incorporating a marker element for correct placement, reduces migration and tissue trauma.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stent is expanded to retain the lumen, then the lumen retention is improved, but the stent applies excessive pressure on surrounding tissue causing traumatic damage and erosion
Solution Approach 1:
The stent is divided into two functional segments: an expandable part with helical windings that applies pressure to retain the lumen, and a retaining part with smaller cross-sectional extension that minimizes contact with surrounding tissue. This segmentation allows the pressure-retaining function to be separated from the tissue-contact function, reducing traumatic damage while maintaining lumen retention.
Solution Approach 2:
Different parts of the stent are designed with different cross-sectional extensions to perform different functions. The expandable part has a larger cross-sectional extension for effective lumen retention, while the retaining part has a smaller cross-sectional extension to minimize tissue contact and trauma. This local differentiation of properties resolves the contradiction between effective retention and tissue protection.
2Ease of manufacture
If the stent is designed with uniform cross-sectional extension, then the manufacturing is simplified, but the stent migrates inside the body cavity
Solution Approach 1:
The stent is segmented into an expandable part and a retaining part with different cross-sectional extensions. The retaining part has a smaller cross-sectional extension that allows it to pass through body cavities and sphincters without obstruction, while the expandable part provides anchoring. This segmentation prevents migration while remaining manufacturable through conventional helical winding processes.
Solution Approach 2:
Instead of designing a uniform stent that expands in place, the invention inverts the approach by having the distal end (retaining part) with smaller cross-section pass through the cavity first, followed by the expandable part that then expands to anchor the stent. This inverted sequence prevents migration during insertion and positioning.
3Ease of operation
If the stent uses material with shape memory effect, then the stent can be inserted in compressed form and expand in situ, but the stent applies excessive pressure causing tissue erosion
Solution Approach 1:
The stent uses shape memory materials but segments them into expandable and retaining parts with different cross-sectional extensions. The expandable part utilizes the shape memory effect for insertion and expansion, while the retaining part with smaller cross-section minimizes tissue contact. This segmentation allows shape memory benefits while reducing tissue erosion.
Solution Approach 2:
Different sections of the stent have different cross-sectional properties despite using the same shape memory material. The expandable part has larger cross-section for effective expansion, while the retaining part has smaller cross-section to minimize tissue trauma. This local quality differentiation resolves the contradiction between ease of operation and tissue protection.
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 maintains lumen retention with reduced migration and tissue trauma, ensuring proper placement and function in body cavities like the urethra and blood vessels.
Implementation Method 1
The present invention relates to a stent for insertion into and placement inside a body cavity of a human being or an animal, said stent being made of a material capable of being readily shaped at body cavity temperature
Implementation Method 2
The super-elastic alloy has a low temperature phase or martensitic phase and a high temperature phase or an austenitic phase
Implementation Method 3
the expandable part is constituted by at least one first section of at least one helical winding in a clockwise direction and at least one second section of at least one helical winding in a counter-clockwise direction, each of said first and second at least one section being radially expandable so that during expansion, the at least one first section will be rotating in counter-clockwise direction and the at least one second section will be rotating in clockwise direction
Data Source
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AI summary
The invention relates to a stent for insertion into and placement inside a body cavity of a 5 human being or an animal, said stent being intended for having a first configuration during insertion into the cavity and said stent, after having been placed in the cavity, being intended for having a second configuration. In an aspect of the invention, an expandable part is constituted by at least one first section of at least one helical winding in a clockwise direction and at least one second section of at least one helical winding in a counter- 0 clockwise direction, each of said first and second at least one section being radially expandable so that during expansion, and where the at least one first section will be rotating in counter-clockwise direction and the at least one second section will be rotating in clockwise direction. In another aspect of the invention, a non-straight curvature of the retaining part is capable of conforming to a curvature of the body cavity, thereby avoiding migration of the stent along the body cavity, and substantially without application of radial forces from the retaining part onto the body cavity walls.