Slotted Polymeric Liners for Catheter Flexibility
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Solution Overview
Problem
Catheters face challenges in navigating tortuous anatomy due to the stiffness of PTFE liners, which reduces flexibility and navigability, especially at the distal end, and the transition to softer materials leads to durability and friction issues, causing potential damage during procedures.
Innovation Solution
The use of polymeric inner liners with customized properties created by slot-type patterns, varying in length and pitch along the catheter shaft, allowing for regions of different stiffness to enhance flexibility and navigability while maintaining durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a PTFE liner is used to provide a smooth, durable, and low-friction surface, then the liner offers excellent lubricity and durability, but the catheter stiffness increases and navigability through tortuous anatomy deteriorates
Solution Approach 1:
The PTFE liner incorporates slots with varying lengths, pitches, and patterns at different locations along the catheter shaft. The distal end features slots with greater spacing and longer lengths to enhance flexibility and navigability through tortuous anatomy, while the proximal end maintains a more continuous structure to preserve durability and low-friction properties. This spatial variation in slot characteristics allows each region to optimize for its specific functional requirements.
Solution Approach 2:
The continuous PTFE liner is segmented by introducing slots that divide the liner into multiple sections. These slots create a series of discrete segments along the catheter length, allowing the liner to flex and conform to anatomical curves while maintaining the overall structural integrity and low-friction surface properties of the PTFE material.
2Ease of operation
If the PTFE liner is terminated proximal to the distal tip and replaced with softer material, then the catheter flexibility and navigability improve, but the liner durability and friction properties deteriorate
Solution Approach 1:
Instead of terminating the PTFE liner and replacing it with softer material, the invention maintains PTFE throughout the entire catheter length but varies the slot characteristics locally. The distal region has slots with greater spacing and longer lengths to provide flexibility and navigability, while the proximal region has a more continuous structure to maintain durability. This approach preserves the low-friction and durable properties of PTFE throughout while achieving the needed flexibility through strategic slot placement.
3Ease of operation
If the PTFE liner transition region is created by mechanical manipulation, then the liner softening is attempted, but the effect is insignificant and the fundamental stiffness problem persists
Solution Approach 1:
The invention changes the structural parameters of the PTFE liner by introducing slots with specific lengths, pitches, and patterns. Rather than attempting to chemically or mechanically alter the PTFE material properties, the slots modify the effective mechanical properties of the liner by creating stress concentration points and flexible zones. This structural parameter change achieves significant flexibility enhancement while maintaining the inherent durability and low-friction properties of the PTFE material.
Data Source
AI summary
Polymeric inner liner, for use with catheters or other medical devices, where the polymeric inner liner tubing can have regions of customized properties created by slot type patterns in the inner liner.