Heating Element Embolic Coil Detachment Mechanism
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Solution Overview
Problem
Current embolic coil delivery systems lack precise control and safety in releasing coils within blood vessels, often resulting in inaccurate placement and potential dislodgment of previously deployed coils, due to stiff catheters and unreliable ejection mechanisms, which are hazardous and difficult to control.
Innovation Solution
A thermally activated release mechanism using a flexible catheter with a heating element and a compressed spring to eject embolic coils from the catheter, where the heating element softens a low-temperature adhesive, allowing the spring to release the coil at a precise location within the vasculature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a stiff pusher wire is used to push the embolic coil out of the catheter, then the coil can be ejected with sufficient force, but the catheter becomes very stiff and difficult to guide through the vasculature
Solution Approach 1:
The catheter is divided into two distinct sections: a flexible delivery catheter for navigation and a separate stiff pusher wire for ejection. This segmentation allows each component to perform its specialized function without compromising the other - the catheter remains flexible for guiding through vasculature while the pusher wire provides necessary ejection force
Solution Approach 2:
The ejection function is extracted from the delivery catheter by using a separate pusher wire that extends through the catheter lumen. The pusher wire can be advanced independently to push the coil out while the catheter itself remains flexible and dedicated to navigation purposes
2Reliability
If the embolic coil is pushed out with a guidewire, then the coil can be released at the target location, but the coil and guidewire shift during movement causing inaccurate placement
Solution Approach 1:
The embolic coil is pre-loaded onto the pusher wire within the catheter assembly before delivery. This preliminary positioning ensures that when the pusher wire advances, the coil moves as a unified assembly without relative shifting between components, maintaining precise placement at the target location
Solution Approach 2:
The coil and pusher wire are combined into a single integrated assembly where the coil is mounted on the pusher wire. This merging eliminates relative movement between the coil and guidewire during delivery, ensuring accurate placement while maintaining reliable release
3Reliability
If the embolic coil is ejected with force to ensure deployment, then the coil can be released from the catheter, but the force causes the coil to overshoot the desired site or dislodge previously deployed coils
Solution Approach 1:
The ejection system uses a dynamic pusher wire that can be advanced in a controlled manner. The operator can regulate the advancement speed and force applied to the pusher wire, allowing gradual deployment of the coil rather than sudden forceful ejection. This dynamic control prevents overshooting while ensuring reliable release
Solution Approach 2:
The system provides visual feedback through fluoroscopy that allows the operator to monitor coil deployment in real-time. This feedback enables the operator to stop the pusher wire advancement at the precise moment the coil reaches the desired location, preventing overshooting and allowing controlled deployment
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
Enables safe, accurate, and precise deployment of embolic coils within narrow blood vessels, reducing the risk of overshooting or dislodging previously placed coils, while maintaining catheter flexibility for navigation through tortuous vascular paths.
Implementation Method 1
a heating element at the distal end of the delivery member for heating the adhesive to a temperature sufficient to soften the adhesive
Implementation Method 2
an ejecting member at the distal end of the delivery member for ejecting the embolic coil from the distal end of the delivery member
Data Source
AI summary
Provided herein are a system, method, and apparatus for delivering a therapeutic device, e.g. an embolic coil, from a delivery tube at a target site in a patient's body. A heating element is disposed in the delivery tube that can be actuated remotely, and a layer of low temperature adhesive is applied at the heating element to retain the therapeutic device. The kicker in the form of, for example, a compressed spring is mounted within the delivery tube so as to be in contact with the therapeutic device for applying a constant ejector force that is countered by the adhesive force of the low temperature adhesive. When the heating element is actuated, the spring's ejector force overcomes the softened adhesive's adhesive force to force the therapeutic device out of the delivery tube.