Micro-coil Detachment Mechanism Using Lost Motion Coupling
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Solution Overview
Problem
Existing micro-coil delivery systems for cerebral aneurysms often result in inadvertent detachment of the micro-coil from the delivery pusher, posing a risk of incorrect timing and impacting treatment efficacy.
Innovation Solution
A delivery device with a retention and detachment mechanism featuring two elongate members, where the first elongate member transitions the mechanism from a locked to an unlocked configuration, allowing for controlled release of the micro-coil using a lost motion coupling mechanism, ensuring reliable retention and preventing inadvertent release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a mechanical detachment system uses a simple retention mechanism, then the device complexity is reduced, but the reliability of preventing inadvertent detachment deteriorates
Solution Approach 1:
The retention mechanism is divided into two separate elongate members (first and second) that work independently but cooperatively. The first elongate member provides primary retention through engagement with the micro-coil, while the second elongate member provides secondary retention and controlled detachment. This segmentation allows each member to have simpler individual structures while collectively providing high reliability.
Solution Approach 2:
The second elongate member is positioned within the lumen defined by the first elongate member and the delivery pusher. Both members are nested within the same delivery system, with the second elongate member specifically positioned to engage with the micro-coil distal end while remaining within the retention zone of the first member. This nested arrangement optimizes space and provides layered retention.
2Reliability
If the micro-coil is securely retained during delivery, then the reliability of preventing inadvertent release is improved, but the ease of operation for controlled detachment deteriorates
Solution Approach 1:
The second elongate member is pre-positioned within the delivery pusher lumen, ready to engage with the micro-coil distal end. The retention mechanism is pre-configured so that when the first elongate member is retracted, the second member automatically engages to provide controlled detachment. This preliminary positioning ensures reliable retention during delivery while enabling easy controlled release when needed.
Solution Approach 2:
The second elongate member acts as an intermediary between the first elongate member and the micro-coil. During delivery, it remains engaged with the micro-coil distal end while being contained within the first member's retention zone. During detachment, it mediates the transition from retained to released state, providing controlled and reliable operation.
Data Source
AI summary
A device for delivering an implant (e.g., an embolic micro-coil) to a vascular disorder of a patient includes a delivery pusher, a moveable element, and first and second elongate members. The delivery pusher defines a lumen between its proximal and distal ends. The moveable element (e.g., a floating tube or a floating coil) defines a passageway therethrough and is disposed within the lumen of the delivery pusher. The first and second elongate members (e.g., core wires) are also disposed within the lumen of the delivery pusher. A portion of each elongate member passes through the passageway of the moveable element. Movement of the first elongate member in a first direction (e.g., retraction of the first elongate member from a locked to an unlocked configuration) causes a time-delayed or lost motion movement of the second elongate member in the same (i.e., first) direction, which releases the implant from the delivery pusher.