Self-Expanding Stent with Inverted Body for Tracheal Support
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Solution Overview
Problem
Conventional stents, primarily adapted from vascular applications, are not optimized for supporting airways and tissue-engineered tracheas, leading to challenges such as irritation, frequent replacement, and difficulty in insertion and removal, particularly in flaccid tissues like tissue-engineered tracheas.
Innovation Solution
A self-expandable stent with a flexible, part-tubular body that inverts from a relaxed to a flexed condition, allowing axial edges to overlap and reduce pressure on the lumen wall, featuring a central portion with negative curvature and axial edges with positive curvature, and anchoring portions that extend outward to prevent migration and provide support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional stents are used in airways and tissue-engineered tracheas, then structural support is provided, but irritation to the lumen wall occurs and frequent replacement is required
Solution Approach 1:
The stent applies different pressures to different regions of the lumen wall through its inverted part-tubular geometry. The axial edge portions are configured to apply less pressure than the central portion, creating a localized pressure distribution that reduces irritation at the edges while maintaining support in the central region.
Solution Approach 2:
The stent employs an inverted part-tubular body where the axial edges overlap or converge toward one another. This inversion allows the stent to provide structural support while minimizing contact pressure at the edges, thereby reducing irritation to the lumen wall compared to conventional stent designs.
2Strength
If conventional stents are inserted into tissue-engineered tracheas, then support is provided, but insertion and removal become extremely challenging
Solution Approach 1:
The stent's inverted part-tubular configuration allows it to be compressed into a compact form for insertion, similar to a nested doll structure. The axial edges overlap to create a smaller profile that can be easily inserted into the lumen, then expanded to provide support, and subsequently compressed again for removal.
3Stability of the object's composition
If a stent provides strong support to flaccid walls, then structural stability is improved, but the pressure on the lumen wall increases causing irritation
Solution Approach 1:
The stent design creates a non-uniform pressure distribution along its length. The central portion applies higher pressure to provide structural stability to flaccid walls, while the axial edge portions apply lower pressure to minimize irritation. This localized differentiation resolves the contradiction between stability and irritation.
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 provides consistent expansion force across varying sizes, minimizes irritation, allows for easy insertion and removal, and is adaptable for different applications, reducing the need for frequent replacement and improving biocompatibility.
Implementation Method 1
a flexible, part-tubular body having an open side with a pair of axial edges extending therealong, the body comprising a central portion and a pair of axial edge portions joining the central portion to the axial edges, at least part of the body being invertible from a relaxed, part-tubular condition to a flexed, inverted part-tubular condition
Data Source
Figure 1
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Figure 3~4
AI summary
A self-expandable stent (1) formed of a flexible, part-tubular body (2), anchoring portions (3) extending from each end of the body (2) and an array (4) of holes or perforations (40, 41, 42) through the body (2) and anchoring portions (3). The body (2) includes an open side (20) and a pair of axial edges (21) extending along a longitudinal axis (L) of the stent (1). The body (2) also includes a central portion (5) and a pair of axial edge portions (6) joining the central portion (5) to the axial edges (21). The central portion (5) of the body (2) is invertible from a relaxed, part-tubular condition to a flexed, inverted part-tubular condition in which the axial edges (21) overlap or converge toward one another for insertion and release in a lumen (TR, TET) to expand, bear against and support a wall of the lumen (TR, TET).