Shape Memory Occlusion Unit for Aneurysm Filling
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Solution Overview
Problem
Current treatments for vascular aneurysms, such as filling with platinum coils or using flow diverters, face challenges like incomplete filling, risk of coil protrusion, and potential occlusion of side branches, particularly in aneurysms with wide necks or complex morphologies, and existing implants are either too rigid or too voluminous for catheter transport.
Innovation Solution
A three-dimensional occlusion unit with a framework of shape memory material struts and a polymer membrane, designed to expand and assume a flexible shape within the aneurysm, featuring a central axial strut and arch struts, with a retractable support wire for catheter passage, and a covering that can be electrospun for enhanced thrombogenicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If platinum coils are used to fill the aneurysm, then the aneurysm sac is filled and thrombus formation is promoted, but the filling is often insufficient and coils may protrude into the blood vessel causing blockages
Solution Approach 1:
The patent employs a flexible membrane covering the coil assembly to contain the coils within the aneurysm sac. This thin film structure prevents coil protrusion into the blood vessel while allowing the membrane to conform to the aneurysm geometry, thereby eliminating the harmful effect of coil migration without compromising the filling effectiveness
Solution Approach 2:
The invention creates a composite structure combining rigid coils with a flexible membrane envelope. The coils provide structural support and thrombogenicity, while the membrane provides containment and flexibility. This composite approach resolves the contradiction by integrating both the filling effectiveness of coils and the safety of containment
2Reliability
If flow diverters with fine mesh size are used to close the aneurysm access point, then the aneurysm neck is effectively closed, but side branches may be covered and occluded
Solution Approach 1:
The patent applies local quality by placing the occlusive membrane only within the aneurysm sac and at the neck region, while deliberately leaving side branches exposed. The membrane's coverage is localized to where it is needed for aneurysm closure, preventing side branch occlusion while maintaining effective neck closure
3Adaptability or versatility
If a three-dimensional implant with multiple tissue layers is used to fill the aneurysm, then the aneurysm morphology can be addressed, but the implant becomes too stiff and bulky for catheter transport
Solution Approach 1:
The patent applies dynamics by using a shape-memory material that can transition between a compressed low-profile state for catheter transport and an expanded three-dimensional state for aneurysm filling. The implant is dynamically deformable, allowing it to be delivered through small catheters and then transform into the desired complex geometry within the aneurysm
Solution Approach 2:
The invention utilizes parameter changes in the shape-memory material's physical state. By changing temperature or applying mechanical activation, the material transitions from a flexible compressed state suitable for delivery to a rigid expanded state that provides structural support and adapts to the aneurysm morphology
4Stability of the object's composition
If the aneurysm neck is covered with a stent to keep coils in place, then coil stability is improved, but the procedure complexity increases and side branches may be occluded
Solution Approach 1:
The patent merges the coil assembly and the containment membrane into a single integrated unit. The membrane is pre-attached to the coil assembly, combining the functions of coil placement and containment into one device. This reduces procedural complexity by eliminating the need for separate stent placement while maintaining coil stability through the integrated membrane enclosure
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 solution provides a flexible, effective occlusion that promotes thrombus formation within the aneurysm while minimizing the risk of coil protrusion and occlusion of side branches, suitable for a range of aneurysm morphologies and sizes, and facilitates transport through small-caliber catheters.
Implementation Method 1
The framework can be formed from a plurality of wires or produced by laser cutting. In any case, the material should possess shape memory properties; nitinol is particularly suitable.
Implementation Method 2
The covering is preferably a polymer membrane, in particular a nanomembrane produced by electrospinning, but any other suitable membrane or covering, for example, made of a plurality of braided or unbraided wires, is also conceivable.
Implementation Method 3
The covering is preferably a polymer membrane, in particular a nanomembrane produced by electrospinning
Data Source
Figure 1
AI summary
The invention relates to an implant for vascular use, which implant can be transported through a catheter and is intended in particular to influence the flow of blood in the area of arteriovenous defects, for example fistulas and aneurysms, to fill the bulge caused by the defect, to promote clot formation and to cover the neck of the defect. The implant according to the invention has an occlusion unit (1, 13) of three-dimensional shape composed of a plurality of sub-units (5a, 14) made from a framework of struts (5, 16, 17), wherein a cover, preferably a membrane (6), is located between struts (5, 16, 17).