Variable Stiffness Catheter via Collapsible Outer Member
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Solution Overview
Problem
Existing flexible shafts and catheters lack the ability to dynamically adjust their stiffness in response to changing conditions, which can limit their effectiveness in navigating complex body lumens.
Innovation Solution
A flexible lumenal member is designed with an inner member, a medial member, and an outer member, where the outer member is collapsible about the medial member, increasing the assembly's stiffness. The medial member can be a stent or a movable support structure, and the outer member can be expanded or inflated to change the stiffness of the catheter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the catheter uses a fixed stiffness structure, then the manufacturing is simple, but the adaptability to navigate complex body lumens is limited
Solution Approach 1:
The catheter employs a dynamic support structure where the outer member can be collapsed about the medial member to change the stiffness of the assembly. This allows the catheter to transition between flexible and stiff states, enabling adaptation to different navigation requirements in complex body lumens while maintaining a relatively simple overall structure.
Solution Approach 2:
The catheter uses a nested configuration where the outer member is collapsible about the medial member. The outer member can be collapsed to reduce the overall diameter and flexibility when needed, or expanded to provide support, allowing the same structure to serve multiple functions without adding significant complexity.
2Reliability
If the outer member is expanded to increase stiffness, then the tracking capability improves, but the flexibility to navigate lumens decreases
Solution Approach 1:
The catheter's outer member can be dynamically collapsed about the medial member to reduce stiffness and increase flexibility for navigation, then expanded to provide rigid support for tracking. This dynamic adjustment allows the same catheter to perform both navigation and tracking functions effectively without requiring separate devices.
Solution Approach 2:
The catheter changes its mechanical parameters (stiffness and flexibility) by collapsing or expanding the outer member about the medial member. This parameter change allows the catheter to adapt its properties to match the requirements of different procedures, improving both navigation capability and tracking reliability as needed.
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 adjustable stiffness of the catheter allows for enhanced navigation through complex body lumens, as it can be made more flexible when needed and stiffer when required, improving its tracking and support capabilities.
Implementation Method 1
the outer member is collapsible about the medial member and wherein the outer member and the medial member are configured such that collapse of the outer member about the medial member increases a stiffness of the assembly
Implementation Method 2
the outer member can be expanded or inflated to change the stiffness of the catheter
Data Source
AI summary
A tubular structure having variable support includes a tubular member and a structural support member with a flexible tubular member over the structural support member, such that the flexible tubular member can engage and disengage or squeeze and release the structural support member. The structural support member can be a tubular mesh, stent, framework, skeleton, braid or other flexible framework. A fluid passage can be used to inflate and deflate the flexible tubular member. Methods of assembly and methods of use are also described.