Catheter Shaft Stiffness Gradient via Crystallinity Control
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Solution Overview
Problem
Current intracorporeal medical devices lack variability in stiffness, which is essential for navigating tortuous anatomical paths and preventing tissue trauma during medical procedures.
Innovation Solution
The development of medical devices with elongated shafts featuring reinforcement members having varying degrees of polymeric crystallinity, allowing for a gradient of stiffness along the device's length, achieved through specific material combinations and manufacturing processes such as extrusion and heating to alter crystallinity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a uniform reinforcement structure is used throughout the catheter shaft, then manufacturing simplicity is maintained, but the catheter cannot navigate tortuous anatomical paths and may cause tissue trauma
Solution Approach 1:
The catheter shaft incorporates reinforcement members with varying degrees of polymeric crystallinity at different locations. The distal portion has lower crystallinity (higher flexibility) while the proximal portion has higher crystallinity (higher stiffness), allowing the shaft to navigate tortuous paths while maintaining structural integrity and preventing tissue trauma.
Solution Approach 2:
The reinforcement member is divided into multiple segments along the length of the catheter shaft, with each segment having different polymeric crystallinity characteristics. This segmentation allows independent optimization of flexibility and stiffness in different regions, resolving the contradiction between maneuverability and structural support.
2Ease of operation
If the distal end of the catheter is made highly flexible to navigate tortuous paths, then maneuverability is improved, but kink resistance deteriorates
Solution Approach 1:
The reinforcement member exhibits a gradient of polymeric crystallinity along its length, with the distal end having lower crystallinity for flexibility and the proximal end having higher crystallinity for kink resistance. This local variation in material properties allows the catheter to be flexible where needed while maintaining strength where required.
3Ease of operation
If the proximal end of the catheter is made highly flexible for easy manipulation, then ease of operation is improved, but pushability and support deteriorate
Solution Approach 1:
The reinforcement member is designed with higher polymeric crystallinity at the proximal end, providing increased stiffness and pushability for effective advancement through the vasculature. The distal end maintains lower crystallinity for flexibility, creating an optimal balance between manipulability and pushability through localized material property variation.
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 design enables enhanced maneuverability, kink resistance, and atraumatic distal ends, improving the effectiveness of medical devices like catheters in navigating complex body pathways while minimizing tissue trauma.
Implementation Method 1
heating the elongated shaft causes the first portion to have a first degree of polymeric crystallinity and the second portion to have a second degree of polymeric crystallinity different than the first degree of polymeric crystallinity
Data Source
AI summary
A medical device may include an elongated shaft. The elongated shaft may further include a reinforcement member having a first portion and a second portion. The first portion may include a polymer having a first degree of crystallinity. The second portion may include a second degree of crystallinity different than the polymer of the first portion.