Mechanical Intravascular Implant Positioner for Reliable Detachment
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Solution Overview
Problem
Current implant delivery systems for vascular defects are cumbersome, unreliable, and prone to false positives, premature detachments, and the generation of metallic or gaseous particulates, with rigid coil-pusher interfaces that complicate navigation through tortuous anatomy.
Innovation Solution
A mechanical positioning system with a flexible and controllable positioner that uses a mechanical implant interface allowing axial and rotational movement, minimizing contact and torsional forces, and employing a frictional mechanism for controlled detachment without hydraulic, thermal, or electrical energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrolytic delivery systems are used to detach the coil from the pusher, then the coil can be released at the target site, but metallic particles are generated during detachment which may cause unwanted embolization downstream
Solution Approach 1:
The patent replaces the electrolytic detachment mechanism with a purely mechanical detachment system. The pusher has a proximal end that is frustoconical in shape, which mechanically engages with the distal end of the coil. Detachment is achieved by simply pulling the pusher back, allowing the frustoconical end to disengage from the coil without generating metallic particles. This mechanical substitution eliminates the harmful electrolytic process while maintaining reliable coil release.
2Reliability
If hydraulic delivery systems are used to detach the coil from the pusher, then the coil can be released at the target site, but air emboli are inevitably injected into the patient during the detachment process
Solution Approach 1:
The patent eliminates the hydraulic detachment system entirely and uses a mechanical friction-based system instead. The pusher's frustoconical proximal end creates frictional engagement with the coil's distal end during delivery. For detachment, the operator simply retracts the pusher, and the frictional engagement naturally releases without requiring hydraulic pressure changes. This mechanical approach completely avoids the risk of air emboli injection associated with hydraulic systems.
3Force
If rigid coil-pusher interfaces are used in delivery systems, then the pusher can effectively push the coil through the microcatheter, but the system becomes cumbersome and difficult to navigate through tortuous anatomy
Solution Approach 1:
The patent employs a dynamic friction-based interface between the pusher and coil. The pusher's frustoconical proximal end creates variable frictional engagement with the coil's distal end. During delivery, friction maintains firm engagement for effective force transmission. During detachment, simple proximal retraction of the pusher reduces frictional engagement, allowing smooth release. This dynamic friction mechanism provides both effective pushing and easy navigation without requiring rigid interfaces.
4Loss of time
If electrolytic delivery systems require constant flow of electrolytes through the microcatheter, then the detachment time can be controlled, but the outer diameter of the delivery system is optimized for saline flow rather than for coil deliverability and pushability
Solution Approach 1:
The patent replaces the electrolytic detachment mechanism with a mechanical friction-based system that requires no electrolyte flow. The pusher's frustoconical end creates mechanical engagement with the coil through friction. Detachment is achieved by simple proximal retraction of the pusher, eliminating the need for electrolyte circulation systems. This mechanical approach allows the delivery system to be optimized for coil deliverability and pushability without the constraints of electrolyte flow requirements.
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 system enables precise, reliable, and efficient deployment of implants with reduced force on the vasculature, minimizing false positives and particulate generation, and allowing for easy retrieval or repositioning of implants.
Implementation Method 1
a frictional fit between a pressure cuff on the distal end of the pusher and a cylindrical solid proximal end of the coil
Data Source
AI summary
An intravascular implant delivery system carries an implant by retaining an engagement member engaging the implant in a position proximal of an aperture at a distal end of the delivery system. The engagement member is retained proximal to the aperture by a cord that obstructs the movement of the engagement member through the aperture. The engagement member is free to rotate and move within an area defined by the delivery system, allowing the implant to react to forces imparted to the implant by the movement of the delivery system and implant through a delivery catheter. Once the implant is in a desired implant position, the cord is moved away from an aperture and the engagement member is allowed to move away from the delivery system.