Twisted Figure-8 Embolic Coil for Irregular Aneurysm Filling
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Solution Overview
Problem
Conventional endovascular coils with complex 3D shapes are inadequate for filling irregularly-shaped and multi-lobed aneurysms, often leaving unfilled areas and increasing the risk of coil protrusion into the parent artery due to high friction during delivery and unpredictable filling behavior.
Innovation Solution
An endovascular coil with a twisted figure 8 shape, featuring a first loop and a second loop rotated about a first axis, forming a figure 8 pattern with an inflection region that can be twisted and overlapped, allowing for better adaptation to irregularly-shaped aneurysms and reduced friction during delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional complex-shaped framing coils are used to fit non-spherical aneurysms, then the coil shape can adapt to the aneurysm geometry, but the friction during delivery through the microcatheter increases significantly
Solution Approach 1:
The coil is designed with a dynamic structure that transitions from a compact low-friction configuration during delivery to an expanded complex shape upon deployment. The framing coil can be compressed into a smaller profile for microcatheter passage, then expands to its intended complex geometry to conform to the aneurysm shape, thereby reducing delivery friction while maintaining adaptability.
Solution Approach 2:
The complex-shaped framing coil is designed to nest within itself or within the microcatheter during delivery. The coil structure allows for self-nesting or nesting within the delivery system, enabling the complex geometry to be collapsed into a compact form that minimizes friction during delivery through the microcatheter.
2Adaptability or versatility
If conventional complex-shaped framing coils with independent axes are used, then the coil can be constrained by the aneurysm shape, but the coil tends to expand beyond the aneurysm dimensions and transfers force to the aneurysm wall
Solution Approach 1:
The coil design incorporates controlled expansion parameters that allow the framing coil to expand to match the aneurysm dimensions without excessive force. By adjusting the coil's structural parameters such as wire diameter, loop spacing, and overall geometry, the expansion force can be optimized to conform to the aneurysm shape while preventing harmful force transfer to the aneurysm wall.
3Manufacturing precision
If conventional complex-shaped endovascular coils are used, then the coil can be designed for specific 3D shapes, but the coil does not fill irregularly-shaped and multi-lobed aneurysms well, leaving unfilled areas
Solution Approach 1:
The framing coil is designed with asymmetric geometries that can better adapt to irregularly-shaped and multi-lobed aneurysms. By incorporating asymmetric loop configurations and varying radii, the coil can conform to complex aneurysm shapes that lack spherical symmetry, thereby improving filling effectiveness without sacrificing manufacturing precision.
4Stability of the object's composition
If conventional complex-shaped framing coils are used, then the coil can provide a stable frame structure, but the coil shifts upon placement of subsequent coils, potentially causing loop protrusion into the parent artery
Solution Approach 1:
The framing coil is designed with preliminary stabilization features that prevent shifting before subsequent coils are placed. This may include pre-formed anchor loops, increased loop density in critical areas, or a frame structure that interlocks with the aneurysm geometry to prevent movement, thereby ensuring reliable coil positioning throughout the procedure.
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 twisted figure 8 coil design effectively fills irregularly-shaped aneurysms with improved packing density and reduced risk of coil protrusion, providing predictable and reliable filling of complex aneurysm geometries while minimizing delivery friction.
Implementation Method 1
rotating the mandrel a first degree of rotation about a point of rotation to induce stress into the embolic coil
Data Source
AI summary
Disclosed are example embodiments of an endovascular coil having a twisted figure 8 shape. The endovascular coil includes: a first loop; a second loop; and an inflection region where a portion of the first loop transitions into a portion of the second loop. The second loop is rotated about an axis parallel to the longitudinal axis of the first loop to create the twisted figure 8 shape. The twist adds more randomness and variability to the filling behavior of the endovascular coil. The added randomness and variability enables the twisted figure 8 coil to better fill the void of irregular-shaped aneurysms than other conventional embolic coils.