Segmented Stent for Neurovascular Conformability
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Solution Overview
Problem
Current stent designs face challenges in approximating the vessel wall in curved, twisted, or forked neurovascular structures, leading to issues like crimping or kinking, which can prevent effective treatment of conditions such as intracranial atherosclerotic disease and hemorrhagic stroke.
Innovation Solution
The development of expandable structures with a tubular member formed from interconnected struts arranged in a specific geometry that allows for enhanced pushability and conformability to the vessel wall, maintaining apposition and preventing kinking, especially in tight corners or bends.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current stent designs are used in tortuous neurovascular vessels, then the stent can be delivered to the target site, but the stent experiences crimping or kinking and fails to maintain wall apposition
Solution Approach 1:
The stent is divided into multiple articulated segments or modules that can rotate and articulate relative to each other, allowing the stent to conform to tortuous vessel geometries while maintaining structural integrity and wall apposition
Solution Approach 2:
The stent employs dynamic articulation mechanisms that allow it to adapt its shape in response to vessel tortuosity, transitioning from a rigid cylindrical form to a flexible configuration that follows the vessel path while maintaining radial force for wall apposition
2Adaptability or versatility
If the stent is designed with high flexibility to conform to tortuous vessels, then the stent can navigate curved paths, but the stent loses axial stiffness and pushability during delivery
Solution Approach 1:
Different portions of the stent have different mechanical properties - the articulation joints provide flexibility for conformability while the stent struts and framework maintain axial stiffness, creating local variations in mechanical quality that satisfy both requirements
Solution Approach 2:
The stent combines materials with different mechanical properties, such as shape memory alloys or nitinol, that provide both flexibility for articulation and sufficient axial stiffness for delivery through the catheter system
3Force
If the stent is designed with high axial stiffness for delivery, then the stent can be pushed through the catheter, but the stent cannot conform to curved or twisted vessel paths
Solution Approach 1:
The stent transitions from a high-stiffness delivered state to a flexible deployed state through articulation mechanisms that activate upon deployment, allowing it to navigate tortuous paths after reaching the target site
4Ease of manufacture
If the stent is made with a simple cylindrical geometry, then the stent is easy to manufacture, but the stent cannot approximate the vessel wall in curved or forked sections
Solution Approach 1:
The stent is segmented into multiple articulating sections that can be manufactured using standard techniques, with the added benefit that the segmented design enables the stent to conform to complex vessel geometries for reliable wall apposition
Data Source
AI summary
Expandable structures for treating blood vessels are disclosed herein. According to some embodiments, the present technology includes a stent, comprising a plurality of struts connected to one another at a plurality of apices, wherein the struts are arranged in a plurality of bands, each band extending around a circumference of the stent. Within a given band, the struts may be connected end-to-end, and may comprise a repeating series of circumferentially adjacent struts. The series may comprise a pair of thin struts each having a first width, a pair of thick struts each having a second width, and an intermediate strut between the thick and thin struts and that has a third width that is greater than the first width and less than the second width.