Pull Wire Shaped Features Prevent Premature Embolic Implant Detachment
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Solution Overview
Problem
Current catheter-based delivery systems for intravascular implants face issues with premature detachment due to increased friction between the pull wire and delivery system as they navigate tortuous vasculature, leading to unintended release of the implant before reaching the treatment site.
Innovation Solution
The delivery system incorporates a pull wire with a shaped feature, such as trapezoidal, triangular, corkscrew, knot, or wave-shaped, made of stainless steel or memory shape alloy, coated with PTFE, which provides frictional resistance against the sidewall of the delivery system's components, and includes a loop wire and flexible coil to secure the implant, preventing premature detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pull wire is used to secure the implant in the catheter, then the implant can be delivered through the vasculature, but friction between the pull wire and delivery system causes premature detachment
Solution Approach 1:
A shaped feature (such as a protrusion, ridge, or angled surface) is introduced as an intermediary element between the pull wire and the delivery system. This feature engages with the delivery system's internal structure to provide mechanical interlocking, reducing friction and preventing premature detachment while allowing controlled movement during delivery.
Solution Approach 2:
The pull wire assembly is segmented into distinct functional zones: a smooth section for passage through the delivery system, a shaped feature section for mechanical engagement with the delivery system, and a retrieval section for implant release. This segmentation allows each portion to perform its specific function optimally without interfering with others.
2Adaptability or versatility
If the delivery system navigates tortuous vasculature, then the implant can reach the treatment site, but friction increases causing pull wire to move proximally
Solution Approach 1:
The shaped feature on the pull wire is designed with curved or rounded geometries that conform to the tortuous path of the vasculature. This curvature allows the pull wire to navigate bends and turns more smoothly, reducing abrupt friction forces while maintaining engagement with the delivery system through the shaped feature's continuous contact points.
Solution Approach 2:
The shaped feature is designed to dynamically adapt to the delivery system's movement through the vasculature. As the delivery system navigates tortuous paths, the shaped feature maintains optimal engagement through controlled friction points, allowing relative movement to be absorbed while preventing complete detachment.
3Strength
If the pull wire is made of stainless steel or memory shape alloy, then the pull wire has sufficient strength, but the friction between pull wire and delivery system increases
Solution Approach 1:
Different portions of the pull wire have different surface properties: the main body maintains smooth, low-friction surfaces for easy passage, while the shaped feature portion has enhanced mechanical engagement surfaces. This local differentiation allows the pull wire to maintain strength where needed while minimizing friction in critical areas.
Solution Approach 2:
The pull wire may incorporate composite construction with a core of stainless steel or memory shape alloy for strength, combined with surface treatments or coatings (such as PTFE) on specific sections to reduce friction. This composite approach combines the advantages of different materials in their optimal locations.
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 solution effectively prevents premature detachment of the implant by maintaining contact with the sidewall, ensuring secure delivery to the target location and controlled release, enhancing the system's flexibility and stability.
Implementation Method 1
the pull wire portion provides frictional resistance against the sidewall of the body
Implementation Method 2
the pull wire is coated with a polytetrafluoroethylene (PTFE) coating
Implementation Method 3
the pull wire is made of a memory shape alloy
Data Source
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Figure 3A~4
AI summary
Disclosed herein are various exemplary systems, devices, and methods for inhibiting premature implant deployment. The delivery member can include a body including a lumen extending therethrough, the body including a compressed distal portion. The delivery member can include a pull wire extending through the lumen. The pull wire can include a pull wire portion that extends radially to abut a sidewall of the body to provide frictional resistance against the body. The pull wire can be positioned to secure the implantable medical device to the delivery member, and the pull wire portion can be effective to inhibit premature detachment of the implant by inhibiting proximal translation of the pull wire due to the frictional resistance provided by the pull wire portion against the body.