Vaso-occlusive Device with Variable Stiffness Core and Outer Layer
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Solution Overview
Problem
Vaso-occlusive devices with larger outer diameters, while potentially better for occupying aneurysm space, become too stiff and unable to bend properly within the vasculature, compromising their effectiveness in filling aneurysms.
Innovation Solution
A vaso-occlusive device is designed with a helically wounded elongated member having a core and an outer layer made from materials with different stiffnesses, such as pure platinum for the core and a platinum-tungsten alloy for the outer layer, allowing for variable stiffness and flexibility by adjusting the dimensions and materials of the core and outer layer, and potentially using multiple coils with varying pitches and materials to achieve the desired flexibility and anchoring properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If larger outer diameter wire is used to form the vaso-occlusive device, then the device occupies more aneurysm space, but the device becomes too stiff and cannot bend properly within the aneurysm
Solution Approach 1:
The patent applies composite materials by constructing the elongated member with a core made from one material and an outer layer made from a different material, where the materials have different stiffness properties. This composite structure allows the device to achieve both adequate strength for space occupation and sufficient flexibility for proper bending within the aneurysm.
Solution Approach 2:
The patent implements local quality by creating a non-uniform stiffness distribution through the core and outer layer structure. The core and outer layer can have different material compositions and thicknesses, allowing different regions of the device to have optimized local properties - the core provides structural integrity while the outer layer provides flexibility, enabling the device to simultaneously occupy space and bend properly.
2Strength
If the outer layer is made from a stiffer material, then the device has greater mechanical strength, but the device loses flexibility needed for delivery and deployment
Solution Approach 1:
The patent uses composite materials with the core made from a stiffer material providing mechanical strength and the outer layer made from a more flexible material providing adaptability. This composite construction resolves the contradiction by combining materials with complementary properties in a single integrated structure.
Solution Approach 2:
The patent applies parameter changes by varying the stiffness parameters of different layers - the core has higher stiffness for strength while the outer layer has lower stiffness for flexibility. By adjusting the material composition, thickness, and stiffness parameters of each layer, the device achieves the optimal balance between mechanical strength and flexibility for both delivery and deployment.
Data Source
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AI summary
Vaso-occlusive device includes a coil having a proximal and a distal end; the coil comprises a helically wounded elongated member having a core and an outer layer, the outer layer made from a metal or alloy that has a different stiffness than a core's stiffness. Vaso-occlusive device includes a first coil and a second coil coupled to each other such that at least one loop from the first coil is between two adjacent loops from the second coil; the first coil is made from a first material, and the second coil is made from a second material stiffer than the first material. Vaso-occlusive device includes an outer coil having a plurality of loops that define a lumen therethrough, and an inner coil located within the lumen of the outer coil; each of the outer and the inner coils is made from a metal or an alloy.