Stent Cell Shape Optimization for Uniform Expansion
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Solution Overview
Problem
Stents used in hollow organs often experience uneven expansion, leading to asymmetric force distribution and increased risk of breakage, particularly near bifurcations, due to inhomogeneous cell expansion behavior.
Innovation Solution
A method for producing stents where the shape of cells is altered and fixed in the expanded state to ensure uniform expansion, using elongated cells to create a beveled end and employing attachment means like needles or mandrels for adjustment, and potentially using memory metals for permanent fixation, allowing for consistent radial force distribution and reduced risk of damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stent is expanded using conventional methods, then the stent can be deployed, but the cells expand unevenly leading to asymmetric force distribution and increased risk of breakage
Solution Approach 1:
The patent modifies the geometric parameters of the cells, specifically the acute angles at the corners, to be smaller than 70° (preferably smaller than 60°). This parameter change in the cell shape enables more uniform expansion behavior and reduces asymmetric force distribution during stent deployment.
Solution Approach 2:
The patent performs preliminary shaping of the cells before the actual expansion process. By pre-configuring the cell geometry with optimized angles and shapes, the stent is prepared in advance to expand uniformly when deployed, preventing asymmetric expansion and reducing breakage risk.
2Force
If the stent is expanded to provide sufficient radial erection force, then the supporting effect is ensured, but the cells may expand too far causing pre-damage of connecting sections
Solution Approach 1:
The patent optimizes the cell shape parameters, particularly the acute angles at the corners, to control the expansion behavior. This ensures that the cells expand to the appropriate degree to generate sufficient radial erection force while preventing over-expansion that would damage the connecting sections.
3Ease of manufacture
If the stent is cut from tubular material and expanded, then the stent can be formed, but the cells near the beveled area stretch asymmetrically due to inhomogeneous force distribution
Solution Approach 1:
The patent specifically modifies the cell shape parameters in the beveled area, reducing the acute angles at the corners to smaller than 70° (preferably smaller than 60°). This parameter change compensates for the inhomogeneous force distribution during expansion, enabling symmetric and uniform cell stretching even near the beveled end.
Solution Approach 2:
The patent applies different cell shape characteristics to different locations of the stent. The cells near the beveled area have specifically optimized acute angles, while other cells maintain standard geometry. This local differentiation ensures uniform expansion behavior across the entire stent structure.
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 method results in a stent with enhanced radial support capabilities, particularly effective at bifurcations, with reduced risk of breakage and improved durability, enabling reliable support of blood vessels and maintaining shape even when temporarily compressed.
Implementation Method 1
the changed shape of the cells of the stent is permanently fixed by means of a heat process. Such a fixation is particularly advantageous when using memory metals, which resume the shape stored by the heating process when the temperature rises.
Implementation Method 2
In addition, the expansion can take place with the supply of heat.
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention is a method for manufacturing a stent (10) in which the stent (10) is cut from a tubular material and expanded to its expanded state. In the expanded state, the shape of the cells (18, 18a, 18b) of the stent (10) is changed and fixed.