Implantable Frame Expansion Members for Controlled Compression Nesting
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Solution Overview
Problem
Existing implantable medical devices face challenges in achieving controlled frame compression profiles, leading to uncontrolled deformation, increased stresses, and irregular strain distributions, which affect reliability and variability in compression ratios.
Innovation Solution
The implementation of radially offset and circumferentially canted or longitudinally splayed frame elements with predetermined angular offsets to facilitate improved shingling and nesting, ensuring even stress distribution and controlled compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional frame elements are used without radial offset, then the structure is simpler, but the compression profile is uncontrolled and stress distribution is irregular
Solution Approach 1:
The frame elements are designed with radially offset portions that create asymmetric geometries. Specifically, certain frame elements have portions that extend radially farther than others, creating an asymmetric pattern around the circumference. This asymmetry enables controlled shingling and nesting during compression, allowing the frame to collapse in a predetermined, uniform manner rather than exhibiting irregular deformation patterns.
Solution Approach 2:
The frame is divided into multiple discrete frame elements with varying radial offsets. Each frame element can be independently designed with specific radial offset characteristics, allowing the overall frame to be segmented into zones with different compression behaviors. This segmentation enables precise control over the compression profile by adjusting the radial offset of individual elements or groups of elements.
2Stress or pressure
If frame elements are compressed without improved shingling design, then the manufacturing is simpler, but the stress distribution becomes concentrated and irregular
Solution Approach 1:
Different portions of the frame elements are designed with different radial offsets, creating local variations in geometry. Specifically, frame elements have radially offset portions at specific locations along the circumference, allowing stress to be distributed more uniformly across the frame structure during compression. This local quality variation ensures that no single area bears excessive stress concentration while maintaining manufacturability through targeted geometric modifications.
3Volume of moving object
If conventional nesting is used without radial offset, then the device packs less efficiently, but the delivery profile is larger
Solution Approach 1:
The frame elements are designed with radially offset portions that facilitate nested doll-style compression. During collapse, frame elements nest within adjacent elements in a predetermined sequence, with radially offset portions interlocking or aligning to create a compact nested configuration. This nesting arrangement significantly reduces the compressed volume of the device, allowing it to be delivered through smaller access paths while maintaining the ability to deploy the full expanded frame structure at the target site.
Data Source
AI summary
A medical device frame including an undulating frame element defining a series of peaks each defining a longitudinal splay angle, circumferential cant angle, or combinations thereof. In some examples, the series of peaks are non-overlapping when the frame is in an expanded configuration and overlap when the frame is in the collapsed configuration. The longitudinal splay angle and/or circumferential cant angle may remain relatively unchanged between the expanded and collapsed configurations (e.g., within about 15%).