Variable Rigidity Wire Guide for Tortuous Vessels
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Solution Overview
Problem
Current catheter wire guide designs face challenges in balancing torsional rigidity and flexibility, often requiring complex manufacturing steps and compromising on torsional rigidity due to tapered distal ends.
Innovation Solution
A wire guide design featuring a cannula with variable rigidity cuts and a flexible portion comprising spheroidal members and a core wire, allowing for enhanced torsional rigidity and flexibility while maintaining reduced manufacturing complexity, with the flexible portion being adjustable to navigate tortuous body passages effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the distal end of the wire guide is tapered to increase flexibility, then the wire guide can traverse tortuous body passages more effectively, but the torsional rigidity of the wire guide is reduced
Solution Approach 1:
The wire guide is divided into distinct segments: a cannula with variable rigidity (full strength proximally, reduced strength distally), a flexible portion with multiple articulating members, and a core wire. This segmentation allows each portion to perform its specific function - the cannula provides structural support and column strength, while the flexible portion with its articulated members enables navigation through tortuous passages without compromising the overall torsional rigidity of the proximal sections.
Solution Approach 2:
Different portions of the wire guide have different mechanical properties tailored to their specific functions. The cannula has variable rigidity along its length, being stronger proximally and more flexible distally. The flexible portion contains multiple members that can articulate relative to each other, providing localized flexibility where needed while maintaining strength in other regions. This local differentiation resolves the contradiction by providing flexibility only where required for navigation.
2Adaptability or versatility
If traditional tapered designs are used to achieve flexibility, then the wire guide can navigate body passages, but additional manufacturing steps are required which increases complexity and time
Solution Approach 1:
Rather than creating a continuously tapered structure requiring complex forming operations, the invention segments the wire guide into discrete components (cannula with variable rigidity, flexible portion with articulated members, core wire) that can be manufactured separately using simpler processes and then assembled. This reduces manufacturing complexity while achieving the desired flexibility.
Solution Approach 2:
The wire guide employs a composite structure combining different materials and components - the cannula (with variable rigidity), the flexible portion members, and the core wire - each potentially made from materials optimized for their specific function. This composite approach allows flexibility to be achieved through the arrangement and properties of discrete components rather than through complex tapering of a single structure.
Data Source
AI summary
A wire guide for feeding a medical catheter through the body passage of a patient to a distant target site within the body has a variably flexible distal portion. The distal portion facilitates threading the guidewire in a tortuous path through acute bends at branch junctions in the body passages of the patient. The wire guide end is able to feed into very delicate vessels such as ventricles of the brain and the spinal canal without puncturing the wall or damaging organs.