Stent With Differential Strut Lengths For Deployment Control
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Solution Overview
Problem
Conventional stents face challenges in achieving balanced mechanical characteristics such as lateral and radial strength, flexibility, and ease of deployment, particularly in regions like the venous system where high strength and flexibility are required, and in areas with mechanical stress like joints, due to uniform strut lengths across the stent body.
Innovation Solution
The stent design incorporates longer struts in end segments compared to intermediate segments, allowing for differential performance requirements, improved deployment accuracy, and reduced radial and lateral forces, enabling smoother deployment and reduced 'jumping' from the delivery device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform strut lengths are used across the stent body, then manufacturing is simplified, but mechanical characteristics such as lateral and radial strength, flexibility, and ease of deployment cannot be optimized for different regions
Solution Approach 1:
The stent body is divided into end segments with longer struts and intermediate segments with shorter struts. This local differentiation allows each region to have optimized mechanical properties: end segments provide flexibility and ease of deployment, while intermediate segments provide radial strength and structural support.
Solution Approach 2:
The stent is segmented into different regions (end segments and intermediate segments) with distinct strut length characteristics. This segmentation enables independent optimization of mechanical properties for each region, resolving the contradiction between manufacturing simplicity and regional strength requirements.
2Ease of operation
If longer struts are used in end segments, then deployment accuracy and flexibility are improved, but manufacturing complexity increases
Solution Approach 1:
Longer struts are specifically implemented in end segments where flexibility and deployment accuracy are critical, while intermediate segments maintain shorter struts for structural integrity. This localized approach optimizes deployment characteristics without unnecessarily complicating the entire stent structure.
Solution Approach 2:
The stent employs asymmetric strut length distribution, with end segments having longer struts than intermediate segments. This asymmetry is strategically designed to improve deployment accuracy and flexibility at the ends while maintaining overall structural coherence.
3Strength
If shorter struts are used in intermediate segments, then radial strength is improved, but flexibility is reduced
Solution Approach 1:
Shorter struts are concentrated in intermediate segments where radial strength and structural support are paramount, while longer struts in end segments provide the necessary flexibility. This spatial differentiation of strut lengths allows each region to excel at its primary function.
Solution Approach 2:
The stent is divided into functional segments with differentiated strut lengths. Intermediate segments with shorter struts provide radial strength, while end segments with longer struts provide flexibility, allowing the overall stent to achieve both properties through regional specialization.
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
This design enhances deployment ease and accuracy, reduces abrupt diameter transitions, and maintains necessary strength and flexibility, particularly in venous regions, by varying strut lengths to meet distinct performance needs at the ends and middle of the stent.
Implementation Method 1
incrementally expanding and heat setting the tubular member, and heat setting the tube at its final diameter
Data Source
AI summary
A stent includes a stent body defining a longitudinal axis and proximal and distal ends. The stent body is expandable from a compressed configuration to an expanded configuration and includes a plurality of stent segments including first and second end segments on opposite ends of the stent body and at least one intermediate segment disposed between the first end segment and the second end segment. Each stent segment defines a plurality of cells. The first end segment defines a plurality of peaks and valleys. The distance between a peak and an adjacent valley of the first end segment is substantially equal to a first length. The at least one intermediate segment defines a plurality of peaks and valleys. The distance between a peak and an adjacent valley of the at least one intermediate segment is substantially equal to a second length that is longer than the second length.