Anchoring Coil Geometry for Wide-Neck Aneurysm Retention
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Solution Overview
Problem
Current vaso-occlusive devices face challenges in effectively occluding small, wide-necked aneurysms due to herniation during placement and retention, with a trade-off between shape stability and softness, leading to potential aneurysm rupture or incomplete filling.
Innovation Solution
A vaso-occlusive device with a pyramidal shape featuring a distal anchoring loop and primary loops that form a triangular pyramid, designed to minimize deformation and provide stable anchoring within the aneurysm, using a platinum alloy wire for flexibility and visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If small, thin vaso-occlusive coils are used to treat small aneurysms, then the device can access small aneurysm sites, but the coils lack sufficient mechanical strength to maintain position and are prone to herniation
Solution Approach 1:
The vaso-occlusive device is divided into multiple coils arranged in a stacked configuration, where each coil contributes to the overall structural integrity. This segmentation allows the device to maintain sufficient mechanical strength while remaining flexible enough for deployment in small aneurysms.
Solution Approach 2:
The device utilizes composite construction with multiple coils of varying densities and materials stacked together. This creates a composite structure that combines the flexibility needed for deployment with the mechanical strength required for chronic retention, solving the contradiction between accessibility and strength.
2Stability of the object's composition
If vaso-occlusive devices are made stiffer to maintain shape stability, then framing capability improves, but the devices become more prone to rupturing delicate aneurysm tissues
Solution Approach 1:
Different portions of the device have different stiffness characteristics. The coils are arranged to provide localized support where needed for framing, while maintaining overall flexibility to avoid rupturing delicate tissues. The stacked configuration allows varying degrees of rigidity in different regions of the device.
Solution Approach 2:
The device employs coils with varying density and stiffness parameters stacked together. This parameter variation allows the device to achieve shape stability for effective framing while maintaining sufficient softness to be atraumatic to delicate aneurysm tissues, resolving the contradiction between stability and tissue safety.
3Shape
If complex three-dimensional shapes are imparted on vaso-occlusive devices to better frame aneurysms, then framing capability improves, but the devices become more prone to deformation during delivery
Solution Approach 1:
The device is pre-formed with its desired three-dimensional stacked coil configuration during manufacturing. This preliminary shaping allows the complex geometry to be established before delivery, and the coils are designed to maintain this configuration throughout the delivery process while still achieving the desired framing capability.
Solution Approach 2:
The stacked coil configuration creates a composite structure that inherently resists deformation during delivery. The multiple coils working together provide structural integrity that maintains the three-dimensional shape while allowing the device to be delivered to the target site, resolving the contradiction between complex shaping and deformation resistance.
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 device effectively prevents herniation and ensures chronic retention within aneurysms, maintaining shape stability while minimizing tissue rupture risk, particularly in small, wide-necked aneurysms.
Implementation Method 1
it is important that vaso-occlusive devices be constructed in a manner that enables their radiopacity during treatment of the aneurysm
Implementation Method 2
The coil is then wrapped around a larger, 'secondary' mandrel, and heat treated to impart a secondary shape
Implementation Method 3
The coil is then wrapped around a larger, 'secondary' mandrel, and heat treated to impart a secondary shape
Data Source
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AI summary
A vaso-occlusive device, comprising a coil formed of a wire having a primary configuration in a constrained condition, the primary configuration having a proximal end and a distal end; wherein the coil assumes a secondary configuration in a relaxed, unconstrained condition, the secondary configuration comprising a primary portion, comprising a plurality of primary loops, including a distal primary loop which is a distal-most loop of the primary loops, the distal primary loop having a proximal end and a distal end, the distal primary loop having turns lying in a first plane and planes substantially parallel to said first plane; wherein, the secondary configuration further comprises a distal anchoring loop connected to the distal end of the distal primary loop, the distal anchoring loop having a substantially triangular shape, the distal anchoring loop having an overall size that is smaller than an overall size of the distal primary loop, the distal anchoring loop positioned within a projection of the distal primary loop.