Electrolytically Detachable Junction Using Multiple Fine Wires
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Solution Overview
Problem
Existing vaso-occlusive devices face challenges in efficient detachment from the treatment site, leading to incomplete detachment and potential complications due to high current densities and detachment byproducts.
Innovation Solution
An electrolytically detachable junction member comprising a plurality of fine stainless steel wires with varying diameters and lengths, coated and uncoated sections, is used to connect the deployment mechanism to the implantable device, allowing for controlled detachment by electrolysis when an electrical current is applied.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single thick wire is used for the junction member, then the structural strength is improved, but the current density increases leading to more detachment byproducts and complications
Solution Approach 1:
The junction member is segmented into multiple fine wires (e.g., 7-19 wires) instead of using a single thick wire. This segmentation reduces the current density in each individual wire, thereby reducing the formation of detachment byproducts and complications while maintaining overall structural strength through the collective arrangement of multiple wires.
2Strength
If a single thick wire is used for the junction member, then the structural strength is improved, but the detachment process becomes less efficient and requires higher voltage
Solution Approach 1:
The junction member is divided into multiple fine wires, which collectively provide sufficient structural strength while enabling more efficient electrolytic detachment. The segmented structure allows current to be distributed across multiple pathways, improving detachment efficiency and reducing the voltage required compared to a single thick wire configuration.
Solution Approach 2:
The invention transitions from a single-dimension (single wire) to a multi-dimension (multiple wires arranged in a pattern) structure. This dimensional change allows the junction member to maintain strength while optimizing the electrolytic detachment process through increased surface area and distributed current flow.
3Device complexity
If fewer wires are used in the junction member, then the device complexity is reduced, but the surface area decreases leading to higher current densities
Solution Approach 1:
The junction member uses a moderate number of fine wires (7-19 wires) arranged in a specific pattern, providing optimal balance between structural complexity and current density management. This segmented approach distributes current effectively while maintaining manageable device complexity.
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 enables efficient detachment with reduced current densities, fewer byproducts, and lower voltage requirements, improving the procedure's efficiency and reducing the risk of complications by increasing the surface area and flexibility of the junction member.
Implementation Method 1
a small electrical current is applied to the core wire to form a clot, which forms a thrombus or collagenous mass that contains the vaso-occlusive device therein. The vaso-occlusive coil is detached from the core wire by electrolysis, in which electrical current applied to the core wire dissolves the stainless steel coil or joint that is exposed to blood and attached to the distal end of the core wire
Data Source
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AI summary
An assembly includes an implantable device, such as a vaso-occlusive coil, a conductive deployment mechanism, such as a conductive pusher or wire, and an electrolytically detachable junction between the deployment mechanism and the coil, the junction comprising fine wires, e.g., stainless steel wires having a small diameter of about 0.00001" to about 0.0025", for example, about 0.0005". The pusher or wire is used to deliver the implantable device through a catheter and to a desired location or treatment site. After the implantable device is properly positioned, electrical current is applied to the fine wires, thereby simultaneously disintegrating the fine wires and leaving the coil at the treatment site.