Adjustable Stiffness Catheter for Tortuous Vessel Navigation
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Solution Overview
Problem
Existing catheters face challenges in navigating through small, tortuous body lumens due to fixed stiffness, which can lead to kinking and vessel perforation, limiting access to remote treatment sites within the body.
Innovation Solution
A catheter with adjustable stiffness, featuring a tubular body composed of multiple layers that can move relative to each other, allowing for manual adjustment of stiffness through an actuator, enabling navigation through tight spaces and varying flexibility as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the catheter is made with fixed variable stiffness (stiffer proximal end, flexible distal end), then the pushability is improved and distal end can bend at required angles, but the catheter cannot adapt to different lumen tortuosity and may kink or perforate vessels
Solution Approach 1:
The catheter employs a dynamic stiffness adjustment mechanism where the tubular body transitions from a fixed stiffness structure to a variable stiffness structure. The inner tube can slide relative to the outer tube, and the actuator enables dynamic reconfiguration of the alternating stiff and flexible segments, allowing the catheter to adapt its mechanical properties in real-time to match the tortuosity and dimensions of different body lumens.
Solution Approach 2:
The catheter changes its physical parameters (stiffness, flexibility) by reconfiguring the relative positions of the inner and outer tubes. The actuator modifies the arrangement of alternating stiff and flexible segments, thereby changing the overall flexibility parameter and minimum radius of curvature to suit different navigation requirements throughout the procedure.
2Adaptability or versatility
If the catheter is made more flexible to navigate tight spaces, then access to remote locations is improved, but the catheter may kink and complicate proper placement
Solution Approach 1:
The catheter is divided into alternating segments of different stiffness within both the inner and outer tubes. This segmentation allows the catheter to bend and navigate tortuous paths through flexible segments while maintaining structural integrity and preventing kinking through stiff segments. The segmented structure enables controlled deformation without compromising the overall reliability of the device.
Solution Approach 2:
The catheter utilizes composite construction with alternating stiff and flexible segments in both inner and outer tubes. This composite structure combines materials or structural configurations with different mechanical properties, allowing the catheter to exhibit both flexibility for navigation and stiffness for maintaining proper placement and delivering therapeutic agents.
3Device complexity
If the catheter uses fixed stiffness structure, then the device structure is simple, but the catheter cannot adapt to varying lumen dimensions and tortuosity throughout the procedure
Solution Approach 1:
The catheter transitions from a static, simple structure to a dynamic structure capable of reconfiguration. The actuator mechanism, while adding complexity, enables the catheter to adapt its stiffness and flexibility characteristics to match varying lumen dimensions and tortuosity, improving overall adaptability throughout the procedural sequence.
Data Source
AI summary
The present invention relates to a catheter that has adjustable stiffness that enables a user to select the stiffness of at least one region of the catheter during insertion and navigation through a body lumen. A preferred embodiment of the invention works in combination with a guidewire to enable placement of the catheter at a position within the vascular system, for example, to enable treatment of a variety of medical conditions. The catheter can include segments that undergo relative movement in response to actuation by the user to adjust the flexibility of the at least one region, preferably located at or near the distal end of the catheter.