Funnel-Connector Hinging Stent for Flexibility Without Kinking
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Solution Overview
Problem
Existing stent designs face challenges in achieving sufficient flexibility to avoid kinking and adopt bent, curved, or twisted configurations while maintaining sufficient rigidity to support vessel walls, resist migration, and be crimped to a balloon catheter without foreshortening.
Innovation Solution
The design incorporates a multi-directional hinging mechanism with elongated connectors forming a funnel shape, allowing the stent to hinge easily in multiple directions with reduced force, while maintaining radial and axial stiffness, and includes a rigid portion to resist bending forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If stents are formed from flexible materials to avoid kinking and adopt bent configurations, then flexibility and ease of deployment are improved, but radial stiffness and axial stiffness are reduced, causing the stent to collapse under anatomical forces and fail to maintain patency
Solution Approach 1:
The stent is divided into multiple segments or cells arranged in a pattern that allows individual elements to flex independently while maintaining overall structural integrity. This segmentation enables the stent to bend and conform to vessel geometry without compromising the radial support provided by each individual cell structure.
Solution Approach 2:
The stent employs composite structural design combining rigid and flexible elements within the same framework. The interwoven pattern of struts creates regions of varying stiffness, where certain areas provide radial support while other regions allow for bending and angulation, achieving both flexibility and strength simultaneously.
2Adaptability or versatility
If stents are formed from flexible materials to avoid kinking, then adaptability to curved configurations is improved, but axial stiffness is reduced, causing the stent to foreshorten and slide off the balloon catheter during delivery
Solution Approach 1:
The stent structure is segmented into multiple interconnected units that can compress and extend axially in a controlled manner during balloon inflation and deflation. This segmentation allows the stent to accommodate axial forces during delivery while maintaining sufficient stiffness to prevent excessive foreshortening and catheter slippage.
Solution Approach 2:
The stent incorporates curved and angled strut configurations that distribute axial loads more effectively throughout the structure. The non-linear geometry of the struts provides mechanical advantage, allowing the stent to resist axial compression forces during balloon delivery while still permitting the necessary flexibility for curved vessel conformability.
3Stability of the object's composition
If connectors are positioned equidistantly around the stent circumference, then structural symmetry is improved, but the ability to hinge in specific directions is reduced
Solution Approach 1:
The connector arrangement transitions from uniform symmetry to asymmetric positioning, with connectors strategically placed at specific circumferential locations to create predetermined hinging axes. This local variation in connector positioning allows the stent to hinge preferentially in specific directions while maintaining overall structural stability through the remaining symmetric framework.
Solution Approach 2:
The stent employs asymmetric connector positioning where connectors are not evenly distributed around the circumference but are instead placed at specific angles and locations. This asymmetric arrangement creates zones of reduced stiffness that facilitate hinging in desired directions, while the overall stent structure maintains sufficient symmetry to provide balanced radial support.
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
An expandable multi-directional hinging stent radially expands from compressed to expanded configurations. The stent includes radially expandable rings aligned in series along a common axis and defining a common lumen of the stent extending through the rings; and elongated connectors extending between adjacent ones of the rings. A first one of the connectors and a second one of the connectors are connected to and extend between a first one of the rings and an immediately adjacent second one of the rings. A shortest distance about a circumference of the stent between a connection point between the first connector and the first ring and a connection point between the second connector and the first ring is less than a shortest distance about a circumference of the stent between a connection point between the first connector and the second ring and the second connector and the second ring.