Pivotable Flange Feet for Secure Valve Anchoring
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Solution Overview
Problem
Current medical instruments for implanting prostheses, particularly in or near the heart and blood vessels, face challenges such as large and inflexible release rings that can get caught during retraction, and stents that struggle to securely attach to non-cylindrical valve areas, leading to potential leakage and incomplete expansion issues.
Innovation Solution
A medical instrument with a manipulator comprising multiple fingers that can change distance from a longitudinal center line, allowing for size reduction post-implantation and featuring pivotable flange feet for secure tissue anchoring, along with a stent design that includes pivotable flange feet for radial expansion and secure anchoring around the valve annulus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large release ring is used to support the prosthesis during implantation, then the prosthesis can be securely held and positioned, but the release ring can get caught on tissue during retraction of the medical instrument
Solution Approach 1:
The release ring is designed with radially movable fingers that can change their configuration dynamically. During implantation, the fingers are in an extended radial position to securely hold the prosthesis. During retraction, the fingers move to a retracted position to avoid catching on tissue, enabling smooth withdrawal of the medical instrument.
Solution Approach 2:
The release ring is segmented into multiple independent fingers rather than being a continuous rigid ring. This segmentation allows each finger to move independently to the retracted position, preventing the entire structure from catching on tissue during instrument withdrawal while maintaining secure prosthesis support during implantation.
2Reliability
If a stent is designed to expand radially for secure anchoring around the valve annulus, then attachment reliability improves, but the stent cannot adapt to non-cylindrical valve areas
Solution Approach 1:
The stent incorporates pivotable flange feet that can dynamically adjust their orientation. These flange feet can pivot to align with the local geometry of the valve annulus, allowing the stent to adapt to non-cylindrical shapes while maintaining secure radial anchoring through controlled expansion.
Solution Approach 2:
Different portions of the stent structure have different degrees of freedom. The flange feet are designed with pivot capability to adapt locally to varying annulus geometries, while the main body of the stent maintains rigid radial expansion for secure anchoring. This local differentiation allows simultaneous adaptation and secure attachment.
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
Facilitates easier retraction of the medical instrument and secure attachment of prostheses to the valve annulus, reducing the risk of leakage and ensuring proper expansion of the valve prosthesis.
Implementation Method 1
A pre-tension of this type can be implemented in different ways, e.g. by using materials with memory characteristics known to the person skilled in the art. The necessary metals, metal alloys—such as nitinol—or plastics—such as memory polymers—with memory characteristics of this type are known to the person skilled in the art.
Implementation Method 2
The bending therefore takes place, as it were, automatically due to the pre-tension.
Implementation Method 3
The change from the initial configuration to the other configuration is effected at a low temperature, for example by laying the material in ice water, as a result of which the material becomes 'soft' and can be actively deformed, and the 'freezing' is effected by lowering the initial temperature to below a first threshold value and then to below a second threshold value.
Implementation Method 4
The undoing of the frozen condition is normally effected by raising the temperature again to above, in the first instance, the second threshold value, and then again to above the first threshold value, wherein the initial configuration is again attained.
Data Source
AI summary
A prosthesis includes a tube with a proximal and distal flange around the tube. The distal and proximal flanges have a radial position, projecting radially outward to clamp tissue between the flanges. The flanges include distal flange feet and proximal flange feet. The distal and proximal flange feet bend from the radial position, against a pre-tension of the memory material, to an extended position, in which the distal and proximal flange feet extend in the longitudinal direction of the tube and are fixable there, returning when released to the radial position urged by the pre-tension. The flange feet have on inner sides a filling to increase the clamping force. The flange feet have a concave-curved part extending from the fixed ends of the flange feet. The hollow side of the concave faces the proximal and/or distal flange and the filling is provided in the hollow side of the concave.