Stent Lattice Web Width Ratio for Uniform Vessel Expansion
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Solution Overview
Problem
Stents with radially compressible and expandable lattice structures face challenges in uniformly expanding within curved blood vessels, leading to uneven radial forces and potential blood clot formation due to non-uniform expansion.
Innovation Solution
A medical device with a lattice structure featuring closed cells, where two stabilizing webs and two connecting webs are designed with different widths, with the connecting webs being S-shaped to enhance flexibility, allowing for better adaptation to curved vessel walls by adjusting radial forces and ensuring uniform expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the stent is inserted into curved blood vessels, then the stent can be delivered to the target location, but the stent expands non-uniformly with more expansion in the transverse direction than in the perpendicular direction
Solution Approach 1:
The patent applies local quality by differentiating the web widths within the lattice structure. Specifically, connecting webs have a first width while stabilizing webs have a second width that is 0.8 to 1.2 times the first width. This local variation in dimensional properties allows different regions of the stent to respond differently to curvature-induced stresses, enabling uniform radial expansion even in curved vessels.
2Adaptability or versatility
If the stent expands non-uniformly in curved vessels, then the stent can follow the vessel curvature, but different radial forces are exerted on the vessel wall leading to local irritation and potential blood clot formation
Solution Approach 1:
The patent employs local quality by creating regions with different web widths. The connecting webs have a first width while stabilizing webs have a second width (0.8-1.2 times the first), allowing specific areas to provide enhanced stability while others maintain flexibility. This local differentiation ensures uniform radial force distribution across the vessel wall, preventing both over-compression and gaps that could cause irritation or clot formation.
Solution Approach 2:
The patent applies parameter changes by systematically varying the web width parameter throughout the lattice structure. By controlling the ratio between connecting web width and stabilizing web width within the 0.8-1.2 range, the stent's mechanical properties are optimized to achieve uniform expansion and consistent radial support, thereby eliminating harmful effects associated with non-uniform expansion.
3Ease of manufacture
If the lattice structure has uniform web widths, then the manufacturing is simpler, but the flexibility and ability to adapt to curved vessels is reduced
Solution Approach 1:
The patent resolves this contradiction by implementing local quality through differentiated web widths. Rather than making the entire structure complex, only specific connecting and stabilizing webs have different widths within the 0.8-1.2 ratio range. This localized differentiation maintains manufacturing simplicity while significantly improving flexibility and adaptability to curved vessels.
Solution Approach 2:
The patent applies parameter changes by systematically varying web width parameters in a controlled manner. The connecting webs have a first width parameter while stabilizing webs have a second width parameter within 0.8-1.2 times the first. This parameter variation enhances flexibility and curved vessel adaptability while maintaining compatibility with standard manufacturing processes.
4Stability of the object's composition
If the stent exerts different radial forces on the vessel wall in different sections, then the stent can maintain structural integrity, but gaps may form between the lattice structure and the blood vessel wall
Solution Approach 1:
The patent applies local quality by differentiating web widths to create regions of varying stiffness. Connecting webs with a first width and stabilizing webs with a second width (0.8-1.2 times the first) work together to distribute radial forces uniformly. This ensures both structural integrity and continuous contact with the vessel wall, preventing gap formation.
Solution Approach 2:
The patent uses parameter changes by systematically adjusting web width parameters throughout the lattice structure. The controlled variation in web widths (with the second width being 0.8-1.2 times the first) optimizes the balance between maintaining structural integrity and achieving uniform contact with the vessel wall, thereby preventing gaps.
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 device achieves improved flexibility and uniform expansion in curved vessels, reducing the risk of blood clots and vessel irritation by distributing forces evenly, while maintaining stability and radial support.
Implementation Method 1
The S-shaped configuration of the connecting webs means that the connecting webs can be deformed more easily. This further improves the flexibility, in particular bending flexibility, of the lattice structure.
Data Source
Figure 1a~2b
Figure 3~4
AI summary
The medical device has a radially compressible and expandable lattice structure (10) that is provided with the closed cells (15) by coupling the four webs. The webs are provided with two stabilization webs (11,13) and connecting webs (12,14). The connecting webs are arranged in parallel and connected with the stabilization webs which are arranged parallely in opposite direction to the connecting webs. The ratio between width (b-1) of stabilization web and width (b-2) of connecting web is 1.2.