Stretch Resistant Embolic Coil Delivery System
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Solution Overview
Problem
Existing catheter-based embolic coil deployment systems face challenges in accurately placing and releasing stretch-resistant embolic devices within the tortuous vasculature of the human brain, particularly in ensuring precise positioning and preventing coil stretching during retrieval.
Innovation Solution
A vascular occlusive embolic device deployment system comprising an elongated flexible catheter, a pusher member with a lumen, and a stretch-resistant member attached to the embolic coil, utilizing an engagement member with an L-shaped configuration and a detachment mechanism to securely hold and release the coil at a predetermined site within a vessel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a conventional catheter-based embolic coil deployment system is used, then the coil can be delivered to the target site, but the coil may stretch or deform during retrieval and repositioning
Solution Approach 1:
The system divides the embolic device into two functional segments: a stretch-resistant member (guidewire) that maintains structural integrity and prevents stretching, and a coil member that performs the embolic function. The guidewire remains in place while the coil can be retrieved and repositioned without stretching the entire assembly, resolving the contradiction between shape stability and operational flexibility.
Solution Approach 2:
The stretch-resistant guidewire acts as an intermediary between the delivery system and the coil member. It provides a stable structural backbone that prevents coil stretching during manipulation, while allowing the coil to be detached, retrieved, and repositioned independently. This intermediary element enables both shape stability and ease of operation.
2Manufacturing precision
If the coil is securely attached to the pusher member for delivery, then positioning accuracy is improved, but the mechanism for releasing and retrieving the coil becomes more complex
Solution Approach 1:
The system replaces complex mechanical release mechanisms with a simple friction-based engagement and release system. The J-shaped distal end of the pusher member engages the guidewire through friction and geometry rather than complex interlocking mechanisms. Release is achieved by simple proximal retraction of the pusher member, reducing device complexity while maintaining positioning accuracy.
Solution Approach 2:
The system extracts the release function from a complex mechanical mechanism and simplifies it to a basic friction-based engagement. The pusher member's J-shaped distal end naturally engages the guidewire during delivery for accurate positioning, then can be easily disengaged by simple retraction, eliminating the need for complex release mechanisms.
3Stability of the object's composition
If the pusher member is made rigid to maintain coil position, then positioning stability is improved, but the ability to navigate tortuous vasculature is reduced
Solution Approach 1:
The pusher member exhibits local quality variations: the distal end is J-shaped and relatively rigid to engage and stabilize the guidewire/coil assembly for accurate positioning, while the proximal portion remains flexible to navigate tortuous vasculature. This local differentiation of rigidity allows the pusher to simultaneously achieve position stability and navigation adaptability.
Solution Approach 2:
The pusher member transitions from a flexible state during navigation to a stabilized engagement state during positioning. The J-shaped distal end dynamically engages the guidewire through friction and geometric interlocking, providing position stability when needed, while the overall member remains dynamically flexible for navigation, resolving the contradiction between stability and adaptability.
Data Source
Figure 1
Figure 1A
Figure 2A~2D
AI summary
A medical device for placing an embolic device at a predetermined site within a vessel of the body including a delivery catheter and a flexible pusher member having a lumen therethrough and being slidably disposed within the lumen of the catheter. A stretch resistant embolic device is retained within the delivery catheter by a mechanical interlocking mechanism which includes an engagement member which is attached to the distal end of the pusher member and extends through a retaining ring at the proximal end of the embolic device. A detachment member extends through an aperture at the distal end of the engagement member thereby locking the embolic device onto the pusher member. The engagement member engages a retaining ring on the embolic device. When the embolic device is advanced to the predetermined site within the vessel, the detachment member is withdrawn from the aperture to thereby release the embolic device at the treatment site.