Stent Struts With Circumferentially Offset Apices
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Solution Overview
Problem
Existing medical stents face challenges in maintaining optimal apposition with the body lumen surface, especially when subjected to bending or compression, which can lead to protrusions and interference between struts, potentially causing thrombosis and reducing fluid flow.
Innovation Solution
The stent design features rows of struts with circumferentially offset peaks and valleys, and unit cells with struts defining apices with different apex angles, which reduces interference between struts during compression by causing them to extend past rather than into each other.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the stent is compressed during bending, then the stent adapts to body lumen curvature, but peaks and valleys of adjacent rows contact each other causing protrusion and interference
Solution Approach 1:
The patent applies asymmetry by circumferentially offsetting the peaks and valleys of adjacent strut rows. Instead of aligning peaks with peaks and valleys with valleys, the design offsets them so that peaks of one row align with valleys of adjacent rows, preventing protrusion and interference during compression while maintaining adaptability to body lumen curvature.
Solution Approach 2:
The patent introduces a circumferential offset dimension to the strut arrangement. By offsetting peaks and valleys in the circumferential direction across adjacent rows, the design creates additional spatial separation that prevents contact and interference during longitudinal compression, solving the problem without compromising bending adaptability.
2Adaptability or versatility
If the stent is compressed during bending, then the stent conforms to curved surfaces, but interference between peaks and valleys decreases apposition to body lumen surface
Solution Approach 1:
The asymmetric offset arrangement ensures that during compression, the offset configuration prevents peak-to-peak or valley-to-valley contact, allowing the stent to maintain smooth apposition to the body lumen surface while conforming to curved geometries.
Solution Approach 2:
By introducing circumferential offset as an additional design dimension, the patent enables the stent to achieve both conformity to curved surfaces and maintained apposition, as the offset prevents strut interference that would otherwise create gaps or protrusions.
3Ease of manufacture
If struts are arranged with aligned peaks and valleys, then manufacturing is simplified, but interference occurs during compression reducing fluid flow
Solution Approach 1:
The patent modifies the symmetric strut arrangement by introducing circumferential offset, which prevents interference during compression and maintains open fluid flow paths, while still allowing for efficient manufacturing through standardized strut components and modular assembly.
Solution Approach 2:
The circumferential offset adds a dimensional parameter to the strut arrangement that prevents interference without significantly complicating manufacturing, as the offset can be achieved through standardized positioning features during assembly or forming processes.
Data Source
AI summary
A stent includes a plurality of unit cells. Within each unit cell, a first set of struts define a first plurality of apices and a second set of struts define a second plurality of apices, wherein a first strut and a second strut of the first set of struts define a first apex with a first apex angle, and the second strut and a third strut of the first set of struts define a second apex with a second, different apex angle. Within each unit cell, a fourth strut and a fifth strut of the second set of struts define a third apex with the first apex angle, and the fifth strut and the sixth strut define a fourth apex with the second apex angle. Each apex of the first plurality of apices is circumferentially offset from another apex of the second plurality of apices.