Catheter Distal Tip Configuration with Varying Durometer
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Solution Overview
Problem
Medical catheters face challenges in navigating through tortuous vasculature due to buckling and kinking, particularly when accessing distal tissue sites like the intracranial vasculature, where they require both flexibility and structural integrity to maintain a small profile and large inner lumen for effective thrombus aspiration or device delivery.
Innovation Solution
A catheter design featuring an inner liner, structural support member, and outer jacket with a tapered outer diameter and varying durometer segments, where the distal section has a higher durometer than the proximal section, and a seamless inner liner, which together resist geometric deformation and kinking, allowing for navigation through tight turns and maintaining a large inner diameter for thrombus aspiration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the catheter uses a uniform flexible structure throughout its length, then it can navigate tortuous vasculature easily, but it buckles and kinks under compression forces
Solution Approach 1:
The catheter is divided into distinct sections with different mechanical properties: a proximal section with higher durometer and structural support members for buckling resistance, and a distal section with lower durometer for flexibility during navigation and engagement with guidewires
Solution Approach 2:
Different portions of the catheter are assigned different material properties - the proximal portion has higher stiffness and structural support for pushability, while the distal portion has lower stiffness for flexibility, allowing each section to perform its specific function optimally
2Reliability
If the catheter uses a thicker wall structure to resist deformation, then it maintains structural integrity, but the inner lumen diameter decreases
Solution Approach 1:
The catheter wall thickness and material properties are optimized locally - the proximal section has thicker walls and higher durometer for structural integrity, while the distal section has thinner walls and lower durometer to maximize inner lumen diameter where flexibility is needed
Solution Approach 2:
The catheter employs composite construction with an inner liner, intermediate layer, and outer jacket with different material properties, allowing the structure to achieve both strength and flexibility without requiring uniformly thick walls throughout
3Ease of operation
If the catheter distal tip is made highly flexible to engage guidewires, then it navigates tight turns easily, but it deforms geometrically under compression
Solution Approach 1:
The catheter is segmented into proximal and distal sections with different mechanical properties, allowing the distal tip to be highly flexible for guidewire engagement while the proximal section maintains geometric stability
Solution Approach 2:
The durometer parameter is changed along the catheter length, with the distal section having lower durometer for flexibility and the proximal section having higher durometer for geometric stability
Data Source
AI summary
In some examples, an outer jacket of a catheter body comprises a first section that decreases in durometer along a length of the first section in a direction towards a distal end of the catheter body, and a second section more distal than the first section and including the distal end of the catheter body, the second section having a higher durometer than a distal portion of the first section. The second section of the outer jacket and the inner liner define a distal opening of the catheter body that is configured to resist geometric deformation when the distal end of the catheter body is engaged with a guidewire.