Vena Cava Filter Flexible Support Rods Puncture Prevention
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Solution Overview
Problem
Current vena cava filters face challenges with endothelial cell growth, difficulty in removal due to water-soluble coatings, and increased risk of blood vessel puncture and twisting, leading to complications and reduced usability.
Innovation Solution
A vena cava filter design featuring conical mesh structures with flexible and protruding sections on supporting rods, arranged in a staggered manner to prevent puncture and twisting, and a smooth transition to reduce the risk of blood vessel wall penetration, ensuring stable fixation and ease of removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the filter is implanted into the inferior vena cava for a certain time, then the filter supporting rod would be climbed and covered by endothelial cells, but the filter becomes difficult to take out and may only be implanted as a permanent filter
Solution Approach 1:
The supporting rod is designed with a flexible section that has lower rigidity than the body portion. This flexible section acts as a transition zone that prevents endothelial cells from climbing along the entire length of the supporting rod, while maintaining the rod's ability to provide structural support. The flexible portion creates a physical barrier that stops endothelial cell migration, thereby preventing the filter from becoming permanently embedded in the vessel wall.
Solution Approach 2:
The supporting rod is divided into distinct segments: a body portion with higher rigidity for structural support, a flexible section with lower rigidity to prevent endothelial cell climbing, and a protruding portion for wall engagement. This segmentation allows each portion to perform its specific function optimally - the rigid body provides strength, the flexible section prevents cell migration, and the protruding portion ensures stable fixation.
2Device complexity
If open supporting rods are used to separate the filter from the blood vessel wall, then the filter structure is simplified, but the supporting rods may be twisted with one another during contraction or spreading
Solution Approach 1:
The flexible section of the supporting rod, with its reduced rigidity, allows the rod to bend and flex during the compression and expansion processes. This flexibility prevents the supporting rods from twisting against each other when the filter is being deployed or contracted, while still maintaining the overall structural integrity and separation function of the filter from the vessel wall.
3Reliability
If open supporting rods are used to abut with the blood vessel wall, then the filter is fixed in position, but the tail end of each supporting rod may puncture through the blood vessel wall
Solution Approach 1:
The flexible section creates a transition zone that reduces the rigidity of the supporting rod near its distal end. This reduced rigidity prevents the tail end from being too sharp or rigid to puncture through the blood vessel wall, while the protruding portion provides controlled engagement with the vessel wall to ensure proper filter positioning without causing damage.
Solution Approach 2:
Different portions of the supporting rod have different local properties: the body portion has high rigidity for structural support, the flexible section has intermediate rigidity for preventing cell climbing and reducing puncture risk, and the protruding portion has specific geometric features for controlled wall engagement. This local differentiation of properties allows the rod to perform multiple functions safely and effectively.
Data Source
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AI summary
A filter (10), comprising a heart-proximal end (1), a heart-distal end (2) and a main filter body connected between the heart-proximal end (1) and the heart-distal end (2). The main filter body comprises a first filter unit (3) and a second filter unit (4), both being conical mesh structures, as well as multiple intermediate connection posts (5) connecting the first filter unit and the second filter unit. The intermediate connection posts (5) have provided thereon support posts (6). A support post (6) comprises a transition segment (61) extending from an intermediate connection post (5) to a blood vessel wall, and a support segment bent and extending from the transition segment (61), and at least partially abutting the blood vessel wall. The support segment comprises a main body (62) bent and extending from the end of the transition segment (61) and a flexible segment (63) bent and extending from the main body (62). A diameter of at least a portion of the flexible section (63) along a length thereof is smaller than a diameter of the main body (62), thereby increasing flexibility of the support section and preventing the support section from puncturing the blood vessel wall.