Stretch-Resistant Embolic Coil with Thermal Detachment Tether
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing implantable microcoils used for vascular embolization lack structural integrity and are difficult to retrieve and reposition due to their flexibility, necessitating the development of stretch-resistant designs for effective deployment and detachment in medical procedures.
Innovation Solution
A system comprising a stretch-resistant embolic coil with a tether that provides both structural support and detachable coupling to a delivery catheter, utilizing a heat-generating apparatus to sever the tether and facilitate efficient detachment, allowing for the deployment and retrieval of implants like coils, stents, and filters within body cavities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If microcoils are made extremely flexible for easy navigation through blood vessels, then ease of delivery is improved, but structural integrity and ability to maintain position deteriorate
Solution Approach 1:
The microcoil is constructed as a composite structure combining flexible wire material with an integrated stretch-resistant member. The stretch-resistant member (made of materials like polyolefin, polyester, or metal alloys) is positioned within the coil structure to provide tensile strength and positional stability, while the outer flexible wire maintains navigability through blood vessels. This composite approach resolves the contradiction by combining materials with complementary properties.
Solution Approach 2:
The microcoil system is divided into distinct functional segments: the flexible coil portion for navigation and the separate stretch-resistant member for structural support. The stretch-resistant member can be integrated through various methods (winding, bonding, or interlocking) but remains a distinct component that can be optimized independently for strength while the coil is optimized for flexibility and delivery characteristics.
2Strength
If a stretch-resistant member is added to provide structural integrity, then strength is improved, but device complexity increases
Solution Approach 1:
The stretch-resistant member is merged with the coil structure through integration during manufacturing. The member is positioned within the coil winds and secured through methods such as winding it through the coil loops, bonding it to the coil material, or interlocking it with the coil structure. This merging approach provides structural integrity while minimizing the appearance of additional complexity in the final deployed device.
Solution Approach 2:
The stretch-resistant member serves multiple functions simultaneously: it provides tensile strength to prevent coil collapse, maintains the coil's shape and position, and can act as an anchor point for detachment mechanisms. By making this single component multi-functional, the overall device complexity is reduced despite the added structural requirements.
3Ease of manufacture
If traditional attachment methods are used without thermal detachment, then manufacturing simplicity is maintained, but detachment time and energy consumption increase
Solution Approach 1:
The attachment system utilizes phase transition of a material (such as a polymer or metal alloy) in response to thermal energy. The material transitions from a solid, bonded state during deployment to a separated or detached state during retrieval. This phase-change mechanism enables rapid detachment by applying thermal energy to trigger the material's phase transition, significantly reducing detachment time compared to mechanical or manual methods.
Solution Approach 2:
The thermal detachment mechanism replaces complex mechanical detachment systems (such as buttons, screws, or latches) with a simpler thermal field-based approach. By using a heating element or thermal energy source, the attachment is released through material property changes rather than mechanical actuation, simplifying the overall system while enabling rapid detachment.
4Speed
If thermal detachment is implemented for rapid release, then detachment speed is improved, but risk of tissue damage from heat increases
Solution Approach 1:
The thermal detachment system applies heat locally and selectively to the attachment interface between the microcoil and the delivery catheter, rather than heating the entire device or surrounding tissue. The thermal energy is concentrated at the specific location where the attachment material undergoes phase transition, enabling rapid detachment while minimizing thermal diffusion to adjacent tissues and reducing the risk of thermal damage.
Solution Approach 2:
The system controls the thermal parameters (temperature, duration, intensity) to match the specific requirements of the attachment material's phase transition. By precisely controlling these parameters, the detachment occurs at the optimal temperature threshold without excessive heat exposure to surrounding tissues, thereby achieving fast detachment while minimizing harmful thermal effects.
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 enhances the reliability and efficiency of implant deployment by providing stretch resistance and rapid detachment, reducing the time and energy required for implant release while minimizing tissue damage and the risk of re-attachment, thus improving the precision and safety of medical procedures.
Implementation Method 1
a heat-generating apparatus to sever the tether and facilitate efficient detachment
Data Source
AI summary
An implantable embolic device having a stretch-resistant member passing therethrough that also serves as a tether for connecting the device to a delivery system. The stretch-resistant member is attached at a proximal and distal end of the device and extends proximally to the delivery device. The proximal attachment point serves to isolate a distal, stretch resisting segment of the member from axial tension placed on a proximal, connecting section of the member. Thus, the portion of the stretch-resistant member being used to connect the embolic device to a delivery device may be placed under tension without placing tension or distorting the implant.