Collet Release Mechanism for Controlled Endovascular Implant Detachment
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Solution Overview
Problem
Existing endovascular implant delivery systems face challenges with premature or failed deployment due to frictional binding and insufficient rigidity, particularly in navigating tortuous vasculature, necessitating improvements in coupling mechanisms for controlled implant release.
Innovation Solution
The implementation of a collet mechanism with flexible fingers that expand radially upon actuation, secured to a delivery tube, allows for secure engagement and controlled release of implants like embolic coils and stents, using a handle-operated actuator to transition between resting and expanded configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical connection with a collar and protrusion is used to retain the implant, then the implant can be securely held during delivery, but friction between the collar and catheter causes binding that prevents controlled advancement
Solution Approach 1:
The retention mechanism is divided into multiple flexible fingers instead of a single rigid collar. Each finger can independently flex and engage with the implant, allowing the system to maintain retention while accommodating the tortuous path of the catheter without binding.
Solution Approach 2:
The retention mechanism transitions from a static rigid structure to a dynamic flexible structure. The flexible fingers can bend and adapt their shape during navigation through the catheter, then expand to securely hold the implant at the treatment site, providing both ease of operation and reliable retention.
2Ease of operation
If a rigid push-rod is used to force the protrusion out of the narrowed cross-section, then the implant can be released, but the push-rod lacks sufficient rigidity to overcome the tortuous path of the vasculature
Solution Approach 1:
The release mechanism uses multiple flexible fingers instead of a single rigid push-rod. Each finger can independently flex to navigate the tortuous vasculature while maintaining enough structural integrity to force the protrusion out of the narrowed cross-section when needed.
Solution Approach 2:
The flexible fingers change their physical state from a flexed configuration during navigation to an expanded configuration during release. This parameter change allows them to adapt to the tortuous path while providing sufficient force to overcome the narrowed cross-section when the implant needs to be released.
3Reliability
If electrolytic release is used to sever the joint between the implant and pusher, then the implant can be detached, but the electric current must be applied for a period of time that extends operation time
Solution Approach 1:
The patent replaces the electrolytic release mechanism with a purely mechanical release system using flexible fingers. This eliminates the need for electrical current application and allows for instantaneous mechanical detachment of the implant from the pusher, significantly reducing operation time while maintaining reliable detachment.
Data Source
AI summary
An implant manipulation system includes a delivery tube, a collet, and an actuator. The collet has a plurality of flexible fingers. The actuator is configured to extend through the delivery tube and the collet and to displace the plurality of fingers radially outward into an expanded configuration. The collet has an outer diameter in a resting configuration and an outer diameter in the expanded configuration that is greater than the outer diameter in the resting configuration.