Segmented Intravascular Guidewire with Composite Cores
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Solution Overview
Problem
Intravascular guidewires face challenges in navigating tortuous vasculature due to the need for balancing torsional, lateral, and tensile strengths while maintaining flexibility, especially in the neurovascular space where small diameters and tortuous paths require precise manipulation and steerability without deformation or kinking.
Innovation Solution
A guidewire design featuring a leading end segment with a nickel-cobalt-chromium alloy core and a nickel-titanium core, both bonded directly without filler, along with a coil member and a polyurethane-tungsten sleeve, allows for enhanced torsional and tensile integrity while enabling flexibility by varying cross-sectional dimensions and material properties to accommodate tortuous paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the guidewire uses a small diameter to navigate narrow neurovascular spaces, then it can access distal reaches of the vasculature, but it loses torsional and lateral stiffness needed for steering
Solution Approach 1:
The guidewire is divided into multiple segments with different material properties: a distal segment with nickel-titanium alloy providing flexibility and a proximal segment with nickel-cobalt-chromium alloy providing stiffness. This segmentation allows each segment to contribute its optimal mechanical properties, enabling the thin guidewire to maintain steering capability while accessing narrow neurovascular spaces
Solution Approach 2:
The guidewire employs composite construction by bonding together core elements made of different materials (nickel-titanium alloy and nickel-cobalt-chromium alloy) with distinct mechanical properties. This composite structure combines the flexibility of nickel-titanium with the stiffness of nickel-cobalt-chromium, achieving both navigation capability and steering control in a single thin guidewire
2Ease of manufacture
If the guidewire uses a single material composition, then it simplifies manufacturing, but it cannot simultaneously provide both flexibility for navigation and stiffness for steering
Solution Approach 1:
Rather than attempting to create a single material with conflicting properties, the guidewire is segmented into distinct sections, each made from materials optimized for specific functions. This approach maintains manufacturing simplicity while achieving the versatility needed for both navigation and steering through controlled material distribution
Solution Approach 2:
Different sections of the guidewire are assigned different material qualities: the distal portion uses nickel-titanium alloy for flexibility and navigation, while the proximal portion uses nickel-cobalt-chromium alloy for stiffness and steering control. This local differentiation of material properties allows the guidewire to exhibit context-dependent mechanical behavior without complicating the overall manufacturing process
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 guidewire effectively advances through tortuous vasculature with improved steerability and reduced deformation, maintaining structural integrity and flexibility, suitable for neurovascular procedures and other interventional applications.
Implementation Method 1
The first material of the first core element has greater rigidity than the rigidity of the second material of the second core element, to thereby facilitate advancement of, and application of torque to, the leading end segment while minimizing deformation
Implementation Method 2
a guidewire having a distal end with improved tensile and torsional integrity, yet with the capability to readily bend in any direction
Implementation Method 3
The first coil segment may have a first torsional strength and the second coil segment may have a second torsional strength greater than the first torsional strength. The second coil segment may be required to assume a greater torsional load to compensate for, e.g., a reduced cross sectional dimension adjacent the tip of the guide member
Data Source
AI summary
A guidewire for use in a medical procedure includes an elongate guide member dimensioned for insertion within a body vessel of a subject. The guide member defines a longitudinal axis and has trailing and leading end segments. The leading end segment has a reduced cross-sectional dimension relative to a cross-sectional dimension of the trailing end segment. The leading end segment includes a first core element comprising a first material and a second core element comprising a second material different from the first material and being forward of the first core element. The first material of the first core element has greater rigidity than the rigidity of the second material of the second core element, to thereby facilitate advancement of, and application of torque to, the leading end segment while minimizing deformation.