Segmented Flow Diverter Stent for Apposition and Low Foreshortening
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Solution Overview
Problem
Existing flow diverters suffer from foreshortening, opening problems, and inadequate apposition to the vessel wall, particularly in treating aneurysms near bifurcations, and prevent further intervention in covered branches due to their high mesh design.
Innovation Solution
A flow diverter stent apparatus combining braided and laser cut segments, with the laser cut segment having shape memory and super-elastic properties, and braided segments with adjustable radiopacity, to provide improved apposition and minimize foreshortening, allowing intervention in covered branches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional braided wire flow diverters are used, then flow diversion function is provided, but foreshortening and opening problems occur
Solution Approach 1:
The flow diverter is divided into multiple segments including a proximal laser-cut segment, a distal laser-cut segment, and an intermediate braided segment. Each segment can be independently optimized for its specific function, allowing the overall device to achieve both adequate length and proper expansion without foreshortening
Solution Approach 2:
The device combines two different construction methods (laser-cut and braided) in a single flow diverter. The laser-cut segments provide structural integrity and resistance to foreshortening, while the braided segment provides flexibility and conformability, creating a composite structure that overcomes the limitations of either method alone
2Reliability
If traditional braided wire flow diverters are used, then flow diversion function is provided, but adequate apposition to vessel wall is not achieved
Solution Approach 1:
Different segments of the flow diverter have different structural properties tailored to their specific locations. The laser-cut segments at the ends provide rigid support for apposition, while the braided intermediate segment provides flexibility to conform to the vessel wall curvature, ensuring adequate apposition throughout the entire device
3Reliability
If high mesh design is used in flow diverters, then flow diversion function is improved, but further intervention in covered branches is prevented
Solution Approach 1:
The flow diverter employs different mesh densities in different segments. The laser-cut segments have lower mesh density with larger interstices that allow passage of microcatheters for further intervention, while the braided intermediate segment has higher mesh density for optimal flow diversion. This local variation in mesh density maintains both flow diversion efficacy and intervention capability
4Reliability
If traditional flow diverters are used, then aneurysm treatment is provided, but treatment of aneurysms near bifurcations is not feasible
Solution Approach 1:
The device incorporates segments with different structural parameters (laser-cut vs. braided construction, different mesh densities, different radial strengths) to adapt to the complex geometry of bifurcation aneurysms. The more flexible braided intermediate segment can navigate bifurcation angles while the laser-cut segments provide stable anchoring, enabling treatment of previously inaccessible aneurysms
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
The combined design ensures better apposition to the vessel wall, reduces foreshortening, and allows for easier navigation and intervention in covered branches, enhancing treatment efficacy for a variety of aneurysms without causing vessel occlusion.
Implementation Method 1
The at least one laser cut segment provides a single piece of laser cut material having shape memory and super-elastic properties so as to form said laser cut segment capable of being inserted into a catheter and having a proximal end, a distal end, and a scaffold extending therebetween
Implementation Method 2
The at least one laser cut segment provides a single piece of laser cut material having shape memory and super-elastic properties
Data Source
AI summary
A flow diverter stent apparatus having a substantially tubular body is disclosed. In at least one embodiment, the apparatus provides an at least one braided segment and an at least one laser cut segment engaged with one another in series so as to form an elongate flow diverter stent. During use of the apparatus, with the apparatus positioned within a catheter and moved to a target area of a patient's vascular system, each of the at least one braided segment and at least one laser cut segment is configured for moving into a shape memorized secondary shape capable of filling the target area as the apparatus exits the catheter.