Catheter Stress Riser Reduces Wire Guide Removal Force
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Solution Overview
Problem
Current rapid exchange or short wire systems for medical catheters lack efficiency and reliability in exchanging devices within a work site, are incompatible with long wire methods, and suffer from frictional resistance and contamination issues, leading to complications in procedures like biliary ERCP.
Innovation Solution
The ultra-short wire technique allows for remote uncoupling of medical devices from the wire guide within the work site, using a shorter guiding member and a catheter with a closed coupling region to facilitate easier manipulation and reduce friction, while an optional coupling mechanism can extend the wire for traditional exchanges, and alignment indicators ensure precise uncoupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a long wire guide is used for traditional over-the-wire exchange, then device exchange can be performed, but physician control over the wire is lost and procedural complexity increases
Solution Approach 1:
The catheter is divided into distinct segments: a coupling region that interfaces with the wire guide, a transition region with reduced wall thickness, and a body region. This segmentation allows the wire guide to be coupled only to the necessary portion of the catheter, enabling shorter wire guides to be used while maintaining physician control during device exchange procedures.
Solution Approach 2:
The coupling mechanism is extracted as a separate functional component from the main catheter body. The coupling region with its port and engagement features can be detached from the wire guide after device delivery, allowing the wire guide to be removed without removing the entire catheter system, thereby simplifying the exchange procedure and improving physician control.
2Strength
If the catheter wall is made thicker for strength, then rupture resistance improves, but the force required to create a stress riser for wire removal increases
Solution Approach 1:
The catheter wall is designed with non-uniform thickness: the body region has sufficient wall thickness for overall strength and rupture resistance, while the transition region adjacent to the access port has reduced wall thickness. This local quality variation allows the catheter to maintain overall structural integrity while requiring less force to create a controlled stress riser at the access port for wire guide removal.
Solution Approach 2:
The catheter structure is made asymmetric with respect to wall thickness distribution. The transition region has deliberately reduced wall thickness compared to the body region, creating an asymmetric structure that concentrates stress at the access port area. This asymmetry facilitates easier wire guide removal through controlled stress riser formation without compromising the overall strength of the catheter.
3Ease of operation
If rapid exchange technique is used with shorter wire guide, then physician control is maintained, but frictional resistance and contamination issues arise
Solution Approach 1:
The coupling region is pre-configured with a port and engagement features that facilitate smooth wire guide insertion and coupling before the procedure begins. The transition region is pre-designed with reduced wall thickness to minimize frictional resistance during wire guide passage. These preliminary design actions reduce friction and contamination risks during the actual device exchange procedure while maintaining physician control.
Solution Approach 2:
The coupling region acts as an intermediary structure between the wire guide and the main catheter body. It provides a controlled interface that reduces frictional resistance during wire guide passage and minimizes contamination risks by creating a sealed coupling mechanism. This intermediary structure facilitates smooth device exchange while maintaining physician control over the wire guide.
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
This method enhances physician control over the wire guide, reduces procedural time, minimizes contamination risks, and allows for seamless transitions between devices without external exchanges, improving the compatibility with both short and long wire systems.
Implementation Method 1
The access port is configured with a stress riser that reduces the force necessary to rupture or split a portion of the shaft wall adjacent to the access port
Data Source
AI summary
A method and apparatus for uncoupling a wire guide from and elongate medical device comprising a catheter shaft having a wire guide lumen extending there through, wherein the material surrounding the wire guide lumen is selected or adapted to facilitate splittability for removal of the wire guide. The catheter shaft includes a wire guide port having a stress riser, the stress riser being configured to reduce the force necessary to rupture or split the portion of the shaft wall adjacent to the wire guide port. In a preferred embodiment, the catheter shaft is coextruded and comprises a plurality of materials. The portion of the shaft adjacent the wire guide lumen is formed from a material is selected or adapted to facilitate splittability as compared to the remaining shaft materials.