Multi-section Stent with Coiled and Lattice Zones
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Solution Overview
Problem
Current stents used to treat peripheral vascular disease in the knee area are prone to kinking and fracturing due to the high magnitude and frequency of axial, radial, and torsional forces, leading to obstructed blood flow and abnormal cell growth.
Innovation Solution
A multi-section stent design comprising a flexible coiled first tubular section and lattice-formed second and third tubular sections, with varying ratios of connector segments to ring segments, allowing for enhanced flexibility and radial strength to withstand diverse forces without kinking or fracturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a stent is designed with high radial strength to withstand forces in the knee area, then it can provide adequate support, but it becomes prone to kinking and fracturing due to the high magnitude and frequency of axial, radial, and torsional forces
Solution Approach 1:
The stent is divided into multiple sections with different structural characteristics. The first section has a coiled structure with high flexibility to accommodate axial, radial, and torsional forces, while the second and third sections have lattice structures with higher radial strength. This segmentation allows each section to perform its specialized function, resolving the contradiction between overall radial strength and resistance to kinking/fracturing.
Solution Approach 2:
Different sections of the stent are designed with different structural properties tailored to their specific functional requirements. The first section features a coiled structure optimized for flexibility and force absorption, while the second and third sections feature lattice structures optimized for radial strength and plaque coverage. This local differentiation of structural quality allows the stent to simultaneously achieve high radial strength and resistance to kinking/fracturing in different locations.
2Strength
If a stent uses a lattice structure with high tie bar frequency to provide strong radial support, then it achieves good plaque coverage, but it reduces flexibility and conformability to vessel walls
Solution Approach 1:
The stent is segmented into different structural zones: a coiled first section providing flexibility and conformability, and lattice-formed second and third sections providing radial strength and plaque coverage. This segmentation allows the stent to achieve both high radial strength and high flexibility by distributing these properties to different sections rather than requiring the entire structure to possess both characteristics simultaneously.
Solution Approach 2:
The stent employs local quality by designing the first section with a coiled structure optimized for flexibility and vessel conformability, while the second and third sections use lattice structures with varying tie bar frequencies optimized for radial strength and plaque coverage. This localized structural differentiation resolves the contradiction by allowing each section to excel at its specific function without compromising the other.
3Ease of manufacture
If a stent is designed as a single uniform structure, then it simplifies manufacturing, but it cannot effectively distribute diverse forces in the knee area without kinking or fracturing
Solution Approach 1:
The stent is segmented into multiple sections with different structural characteristics (coiled first section, lattice-formed second and third sections) to effectively distribute and manage diverse forces in the knee area. Each section is designed to handle specific force types, with the coiled section absorbing axial, radial, and torsional forces while the lattice sections provide radial support. This segmentation improves reliability without significantly complicating manufacturing, as each section can be produced using similar techniques and then assembled.
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 blood flow and prevents stent fractures, reducing the risk of restenosis and abnormal cell growth by distributing forces more evenly and providing adequate radial strength.
Implementation Method 1
a first tubular section (12) formed of a coil (26)
Implementation Method 2
a second tubular section (18) formed of a first lattice (22) and a third tubular section (20) formed of a second lattice (24)
Data Source
Figure 1
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AI summary
A multi-section tubular device suitable for use as a stent is provided. The multisection tubular device includes a first tubular section (12) having a first end and a second end. A second tubular section (18) is connected to the first end of the first tubular section and a third tubular section (20) is connected to the second end of the first tubular section. The first tubular section is more flexible than the second and third tubular sections. One advantage is that the coiled first tubular section is highly flexible axially, radially, and torsionally, which makes the multi-section tubular device resistant to kinking or fracturing.