Shape Memory Steering Wire for Tight-Curvature Catheter Navigation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current steerable devices, such as shape memory alloy steering devices, have limitations in achieving high deflection angles with tight curvature radii, are difficult to assemble, and are prone to wear, making them cumbersome and less effective in navigating complex anatomies.
Innovation Solution
An elongated steerable device with a shape memory alloy wire secured to a distal extremity, activated by an actuator, allowing for a curvature angle between 0 and 360°, featuring a flexible and strong design with a U-shaped configuration and elastic element for easy navigation and precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If shape memory alloy wires are used for steering, then the device can achieve deflection, but the curvature radius is wide and deflection angles are limited
Solution Approach 1:
The steerable device is divided into multiple independent steering sections, each with its own shape memory alloy wire. This segmentation allows each section to achieve high deflection angles independently, while collectively enabling navigation through complex anatomies with tight curvature radii.
Solution Approach 2:
The invention employs pre-formed curved configurations in the shape memory alloy wires and flexible member to achieve tight curvature radii. The device is designed with predetermined curved shapes that can be activated to navigate through tortuous conducts with high deflection angles.
2Strength
If shape memory alloy wires are crimped at both extremities, then the structure is firm, but assembly is difficult and wear occurs quickly
Solution Approach 1:
The invention extracts the crimping requirement from one end of the shape memory alloy wire, securing it firmly only at the distal extremity while leaving the proximal extremity free for easy connection to the actuator. This eliminates the difficult assembly process while maintaining structural firmness where needed.
Solution Approach 2:
A flexible member serves as an intermediary between the shape memory alloy wire and the actuator, transmitting the actuation force without requiring firm mechanical connection at the proximal end of the wire. This intermediary element simplifies assembly while maintaining effective force transmission.
3Device complexity
If shape memory alloy wires with low contraction rate are used, then the device is simple, but high deflection angles with tight curvature are difficult to obtain
Solution Approach 1:
The invention changes the geometric parameters of the device configuration, including the arrangement and pre-curvature of shape memory alloy wires, to achieve high deflection angles. By optimizing the geometric configuration rather than relying solely on material contraction rate, the device achieves tight curvature radii while maintaining simplicity.
Solution Approach 2:
The device incorporates pre-formed curved configurations and geometric arrangements that amplify the deflection effect, enabling high curvature angles to be achieved even with shape memory alloy wires having moderate contraction rates.
4Ease of operation
If the device is made flexible for easy navigation, then navigation is improved, but the device may lack strength to drive catheters
Solution Approach 1:
The device exhibits different mechanical properties at different locations: the distal section with shape memory alloy wires provides flexibility and steering capability for easy navigation, while the proximal section maintains sufficient strength to drive catheters and endoscopes through the flexible member.
Solution Approach 2:
The flexible member is constructed as a composite structure combining materials with different mechanical properties, providing both the flexibility needed for navigation and the strength required to drive medical devices through the lumen.
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 device enables easy handling, compact design, and repeatable curvature, improving mobility and accessibility to hard-to-reach areas, reducing the need for exchange guides and enhancing surgical precision.
Implementation Method 1
at least one shape memory alloy wire presenting at least one activable zone and secured to the distal extremity of the elongated flexible member
Implementation Method 2
an actuator configured to activate the at least one shape memory alloy wire from the proximal extremity of the elongated flexible member
Data Source
AI summary
An elongated steerable device for guiding a catheter or an endoscope comprising an elongated flexible member, at least one shape memory alloy wire (16) presenting at least one activable zone, and an actuator configured to activate the at least one shape memory alloy wire, wherein the activable zone (17) of the at least one shape memory alloy wire (16) is configured to present a resting configuration and an activated configuration, the activated configuration displaying at least one predetermined curvature (C1, C2), and wherein the activable zone (17) of the at least one shape memory alloy wire (16) is configured to adopt the activated configuration when activated by the actuator, thus inducing the predetermined curvature (C1, C2) to the distal extremity (12D) of the elongated flexible member (12).