Catheter Assembly With Segmented Inner Body Rigidity
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Solution Overview
Problem
Existing catheter assemblies for the head and neck region face challenges in transmitting pushing force and torque due to buckling or bending, and they often lack sufficient flexibility and steerability, which can lead to vessel damage and poor positioning.
Innovation Solution
A catheter assembly with an outer catheter and an inner catheter, where the inner catheter has a flexible distal tip, a physical property transition section, and a second body section with a reinforcing material layer, allowing the distal portion to protrude beyond the outer catheter and ensuring appropriate flexural rigidity relationships, enhancing steerability and pushability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the distal portion of the guiding catheter is made more flexible to reduce vessel damage, then vessel safety is improved, but steerability deteriorates
Solution Approach 1:
The inner catheter body is divided into multiple sections with different flexural rigidities: a distal body section with lower rigidity for flexibility, a first body section with intermediate rigidity, and a proximal body section with higher rigidity for steerability. This segmentation allows each section to perform its specific function while maintaining overall system performance.
Solution Approach 2:
Different sections of the inner catheter are assigned different local properties: the distal section has lower flexural rigidity to reduce vessel damage, while the proximal section has higher flexural rigidity to improve steerability. The reinforcing material layer is selectively positioned to create these local property differences.
2Ease of operation
If the inner catheter includes a reinforcing material layer extending to the distal end, then steerability is improved, but flexibility of the distal portion deteriorates
Solution Approach 1:
The reinforcing material layer is segmented to extend only to a specific position within the inner catheter body, not to the distal end. This creates a distal body section without the reinforcing layer, maintaining flexibility where needed while providing steerability in the proximal sections.
Solution Approach 2:
The reinforcing material layer is selectively applied to specific sections of the inner catheter body to create local differences in flexural rigidity. The distal body section has no reinforcing layer for flexibility, while proximal sections have the reinforcing layer for steerability.
3Stability of the object's composition
If the distal portion of the inner catheter has higher rigidity than the outer catheter, then structural stability is improved, but the inhibitive effect on blood vessel damage deteriorates
Solution Approach 1:
The inner catheter is segmented into sections with different flexural rigidities, with the distal body section having lower rigidity than the outer catheter's distal portion. This ensures the distal tip remains flexible for vessel safety while proximal sections maintain structural stability.
Solution Approach 2:
The inner catheter is designed with non-uniform flexural rigidity along its length. The distal body section has lower rigidity to match the flexibility requirements of the outer catheter's distal portion, while proximal sections have higher rigidity for structural support.
4Productivity
If pushing force is applied to move the guiding catheter in the distal direction, then insertion progress is improved, but deflection of the distal portion increases reducing moving distance
Solution Approach 1:
The inner catheter body is segmented into sections with progressively different flexural rigidities from distal to proximal. This gradient structure allows efficient force transmission from proximal pushing to distal movement while minimizing deflection through the stiffer proximal sections.
Solution Approach 2:
The flexural rigidity parameter is changed along the length of the inner catheter body, creating a gradient from lower rigidity at the distal end to higher rigidity at the proximal end. This parameter variation optimizes both flexibility for navigation and stiffness for force transmission.
Data Source
AI summary
A catheter assembly comprises an outer catheter including an outer catheter body and an outer catheter hub at a proximal portion of the outer catheter body; and an inner catheter including an inner catheter body insertable in the outer catheter body, a tip at the distal portion of the inner catheter body which is rich in flexibility, and an inner catheter hub at the proximal portion of the inner catheter body adapted to be coupled to the outer catheter hub. The inner catheter body includes a flexible section connected the tip, a physical property transition section on the proximal side of the flexible section, a first body section on the proximal side of the physical property transition section, a second body section on the proximal side of the first body section, greater than the first body section in flexural rigidity, and having a reinforcing material layer.