Variable Radial Force Stent Design for Reduced Inflammation
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Solution Overview
Problem
Conventional stents face challenges in minimizing tissue inflammation and swelling due to excessive radial force when implanted in body lumens, which can lead to extended inflammatory zones and granulation tissue formation.
Innovation Solution
A stent design with variable radial force along its longitudinal length, featuring serpentine bands with adjustable strut angles, wall thickness, and strut pairs, where the radial force decreases from the center to the ends, reducing the risk of excessive tissue reaction by distributing force more evenly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stent is designed with high radial force to maintain patency in body lumens, then the stent can effectively keep the lumen open, but excessive radial force causes extended inflammatory zones and granulation tissue formation
Solution Approach 1:
The stent applies different radial forces to different regions of the lumen based on local needs. The center portion exerts higher radial force to maintain patency in the stenotic region, while the end portions exert lower radial force to minimize tissue inflammation and granulation. This spatial variation in force distribution resolves the contradiction between maintaining effectiveness and reducing harm.
2Ease of manufacture
If a stent applies uniform radial force along its entire length, then the manufacturing and design are simplified, but it causes excessive inflammation at the ends where less force is needed
Solution Approach 1:
The stent structure is divided into regions with different mechanical properties. The center portion has structural characteristics that provide higher radial force, while the end portions have characteristics that provide lower radial force. This local differentiation addresses the inflammatory issue without requiring complex manufacturing, as it can be achieved through variations in strut geometry and arrangement.
3Object-affected harmful factors
If the stent has a larger diameter to reduce tissue reaction, then inflammation is minimized, but the stent cannot effectively maintain patency in stenotic regions
Solution Approach 1:
The stent is designed with region-specific functionality where the center portion has a smaller diameter to effectively treat the stenotic region and maintain patency, while the end portions have a larger diameter to minimize tissue reaction and inflammation. This spatial variation allows both contradictory requirements to be satisfied in their respective locations.
Data Source
AI summary
A stent of the present disclosure has a variable radial force along the longitudinal length of the stent. In particular, the radial force of the center is greater than the radial force of the ends of the stent. Without being bound by theory, the radial force is affected by the strut angle θ, the wall thickness t, the number of strut pairs, and combinations thereof. In one aspect of the present disclosure, the stent has a variable strut angle θ, a variable wall thickness t, and a variable number of strut pairs. By adjusting the strut angle θ, the wall thickness t, and the number of strut pairs of the serpentine bands, the stent will have a variable radial force without the need for additional processing steps.