Expandable Aneurysm Device with Segmented Wire Density
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Solution Overview
Problem
Current treatments for cerebral aneurysms lack effective methods to obstruct blood flow to and from the aneurysm while allowing for thrombotic reactions, and existing devices often fail to prevent coils from exiting the aneurysm.
Innovation Solution
An intravascular device with an externally controllable expandable member made of wires, featuring a dense wall portion to obstruct radial flow and a less dense portion to allow axial flow, which can be adjusted to align with the aneurysm neck, and a mechanism to introduce coils to induce clotting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dense wall portion is used to obstruct radial blood flow to the aneurysm, then thrombotic reaction is promoted, but coils may be trapped inside the aneurysm and unable to exit
Solution Approach 1:
The expandable member is divided into multiple segments with different wire densities: a first wall portion with smaller openings (higher density) to obstruct radial flow and promote thrombosis, and a second wall portion with larger openings (lower density) to allow coil exit. This segmentation resolves the contradiction by spatially separating the flow obstruction function from the coil release function.
Solution Approach 2:
Different portions of the expandable member have different local properties: the first wall portion has smaller openings specifically positioned to obstruct radial blood flow to the aneurysm dome, while the second wall portion has larger openings to facilitate coil extraction. This local quality differentiation allows simultaneous achievement of thrombotic promotion and coil release capability.
2Reliability
If the expandable member has small openings to prevent coil exit, then coils are retained in the aneurysm, but radial blood flow is not sufficiently allowed
Solution Approach 1:
The device segments the wall structure into two functional zones: the first wall portion with small openings that acts as a filter to retain coils while blocking radial flow to the aneurysm, and the second wall portion with large openings that permits radial blood flow. This segmentation simultaneously achieves coil retention and maintains necessary blood flow.
Solution Approach 2:
The expandable member incorporates local quality variations where the first wall portion has densely packed wires with small openings for coil retention and flow obstruction, while the second wall portion has sparsely packed wires with large openings for blood flow. This local differentiation resolves the contradiction between coil retention and blood flow maintenance.
3Quantity of substance
If the expandable member allows large openings for blood flow, then radial blood flow is maintained, but coils can exit the aneurysm
Solution Approach 1:
The expandable member is segmented into a first wall portion with small openings positioned to obstruct radial flow paths leading to the aneurysm dome, and a second wall portion with large openings positioned to allow coil exit. This spatial segmentation ensures that blood flow obstruction and coil retention occur in one zone while blood flow maintenance occurs in another zone.
Solution Approach 2:
Different local regions of the expandable member have different opening sizes: the first wall portion has locally small openings (cross-sectional area ratio 1:1.5 to 1:3.8 compared to the second portion) that prevent coil passage while blocking radial blood flow, whereas the second wall portion has locally large openings that permit both blood flow and potential coil exit if needed.
4Reliability
If the expandable member is made fully dense to obstruct all radial flow, then thrombosis is maximized, but non-radial blood flow in the vessel is interfered with
Solution Approach 1:
The expandable member implements local quality differentiation where the first wall portion has small openings specifically oriented to obstruct radial blood flow to the aneurysm while the second wall portion has large openings that preserve non-radial and axial blood flow through the vessel. This local differentiation maximizes thrombotic effect on the aneurysm while minimizing interference with overall vessel hemodynamics.
Data Source
AI summary
An intravascular device for treating a cerebral aneurysm which has an externally controllable expandable member, the expandable member has a plurality of wires that define walls of the expandable member; where in a relaxed state of the expandable member the walls have at least a first wall portion in which openings defined between the wires are small enough to prevent coils positioned within the aneurysm from exiting the aneurysm, the first wall portion has an axial length at least as long as a neck of the aneurysm; and at least a second wall portion in which openings defined between the wires are large enough to allow blood flow through; the second wall portion axially aligned relative to the first wall portion.