Undulated Catheter Skeleton for Tortuous Pathway Navigation
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Solution Overview
Problem
Existing catheters face challenges in navigating through bifurcations, tortuous pathways, and stenoses due to inadequate navigational behavior.
Innovation Solution
A catheter design featuring a skeleton wall section with an interrupted tubular reinforcement wall, an inner liner, and an outer laminate, where the skeleton has an undulated distal end edge with alternating undulation tops and bottoms, providing a gradual transition in bending stiffness, enhanced by a heat-shrinkable outer tube during manufacturing to maintain structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a catheter uses a fully uninterrupted tubular reinforcement wall, then structural strength and rigidity are improved, but navigational flexibility through bifurcations and tortuous pathways deteriorates
Solution Approach 1:
The continuous tubular reinforcement wall is segmented into discrete skeleton elements arranged in a periodic pattern. This segmentation creates gaps between reinforcement elements, allowing the catheter to bend and flex more easily while still maintaining overall structural integrity through the distributed skeleton structure.
Solution Approach 2:
The catheter wall exhibits spatially varying properties: the skeleton range (distal 30mm) contains the interrupted tubular reinforcement for flexibility, while more proximal sections may have different reinforcement configurations. This local differentiation allows the distal tip to be highly flexible for navigation while maintaining adequate strength for delivering medical therapy.
2Ease of operation
If a catheter uses an interrupted tubular reinforcement wall with high cut-away ratio, then navigational flexibility is improved, but structural strength and stability deteriorate
Solution Approach 1:
The catheter is pre-formed with a specific skeleton pattern during manufacturing that anticipates the flexibility-strength balance needed. The periodic arrangement of skeleton elements with controlled cut-away ratios (40-90%) is established in advance to provide predictable mechanical behavior during navigation and deployment.
Solution Approach 2:
The catheter wall combines multiple materials with complementary properties: the reinforcement material (e.g., shape memory alloy or nitinol) provides both flexibility and structural support, while the inner liner and outer laminate layers provide additional mechanical properties. This composite structure achieves both navigational flexibility and structural stability.
3Strength
If the skeleton range extends further proximally, then structural support is improved, but catheter flexibility and ability to follow tortuous pathways deteriorates
Solution Approach 1:
The catheter skeleton is designed with dynamic characteristics through the use of shape memory materials and the periodic interrupted structure. This allows the catheter to transition between flexible and supportive states as needed during navigation and deployment, adapting to different anatomical conditions along its length.
Data Source
Figure 1~2
Figure 3A~3B
Figure 4
AI summary
A catheter comprises a tubular catheter wall, which comprises a skeleton wall section, which is at least extending between 30 mm and 4 mm proximal from the distal end of the catheter. The skeleton wall section comprises a skeleton (7), which has a distal skeleton end edge (6), which is extending in an endless manner all around a center line of the catheter wall. The distal skeleton end edge (6) is an undulated edge, which comprises N undulation tops (21, 22) and N undulation bottoms (31, 32). Axial distances (H) between each undulation top and each undulation bottom are at least 10% of an outer diameter (D) of the skeleton wall section. Said N undulation tops (21, 22), as well as said undulation bottoms (31, 32), are substantially equally angularly spaced relative to one another. The catheter exhibits improved navigational behaviour through bifurcations and/or tortuous pathways and/or stenoses.