Variable Stiffness Wire Guide for Vascular Navigation
Solution Overview
Problem
Conventional wire guides face a dilemma in achieving the necessary stiffness for vascular procedures while maintaining flexibility to avoid damaging blood vessels, particularly in tortuous passageways and bifurcations, as increased stiffness often compromises flexibility and vice versa.
Innovation Solution
A variable stiffness wire guide design featuring a core element with an outer and inner coil, where the shaft element's axial movement adjusts the inner coil's length, allowing for customizable flexibility by altering the relative positions of the coils and core element, and incorporating a locking mechanism for fixed positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the wire guide is made stiffer to provide sufficient support for vascular procedures, then the wire guide can be pushed through the vascular system without kinking, but the wire guide may damage vessel linings when being advanced
Solution Approach 1:
The wire guide incorporates a variable stiffness mechanism where a shaft element can be moved axially to change the length of the inner coil, thereby dynamically adjusting the flexibility of the wire guide body. This allows the wire guide to have different stiffness levels at different positions or during different phases of the procedure
Solution Approach 2:
The flexibility of the wire guide is changed by altering the axial position of the shaft element, which changes the length of the inner coil. This parameter change allows the wire guide to transition between flexible and stiff states to match different procedural requirements
2Ease of operation
If the wire guide is made more flexible to pass through tortuous passageways without damaging blood vessels, then the wire guide can navigate complex vascular structures, but the wire guide may not provide sufficient support for stent delivery and manipulation
Solution Approach 1:
The wire guide allows dynamic adjustment of flexibility by moving the shaft element axially. During navigation through tortuous passageways, the wire guide can be in a more flexible state, and during stent delivery and manipulation, it can be made stiffer by changing the inner coil length
Solution Approach 2:
The flexibility parameter is changed by adjusting the axial position of the shaft element, which changes the inner coil length. This enables the wire guide to have different flexibility parameters at different times during the procedure
3Ease of operation
If the wire guide is made extremely flexible to allow grasping and manipulation at bifurcations, then the wire guide can be manipulated without damaging tissue around the bifurcation, but the wire guide may not be kink resistant during grasping
Solution Approach 1:
The wire guide allows dynamic adjustment of stiffness by moving the shaft element. During grasping and manipulation at bifurcations, the wire guide can be made stiffer by changing the inner coil length to prevent kinking, while still maintaining enough flexibility for manipulation
4Strength
If a stiffer wire guide is used to provide support for challenging take-off and tortuosities, then the wire guide can straighten the vessel, but the wire guide is so stiff it can damage vessel linings
Solution Approach 1:
The wire guide incorporates a dynamic stiffness adjustment mechanism where the shaft element can be moved to change the inner coil length. This allows the wire guide to provide maximum support when needed while reducing stiffness to avoid damaging vessel linings during advancement
Data Source
AI summary
The present invention generally relates to a medical surgical device and specifically a wire guide for percutaneous placement within a body cavity. The flexibility of the wire guide may be varied while it is in place within the body vessel.