Catheter Outer Layer Anchoring via Protrusion Parts
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Solution Overview
Problem
Catheters face issues with the outer layer detaching from the inner layer when pulled in the axis direction, particularly due to stress concentration at the joining region during insertion through curved blood vessels or ducts, leading to potential detachment during procedures for stenosis or obstructed segments.
Innovation Solution
A catheter design featuring a tubular inner layer with a reinforcement layer and an outer layer where the inner layer has an uneven outer surface with protruded and depressed portions, and the outer layer has protrusion parts that extend deeper than the reinforcement layer, enhancing the anchoring effect and reducing detachment risk by distributing stress more evenly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a protruding portion is provided in the inner layer to enhance joining strength, then the joining strength between inner layer and outer layer is improved, but stress concentration occurs on the joining region during catheter bending, making the outer layer susceptible to detachment
Solution Approach 1:
The invention applies different structural features at different locations: protruding portions are provided at the proximal end to prevent distal detachment, while depressed portions are provided at the distal end to prevent proximal detachment. This local differentiation addresses the specific detachment risks at each end of the catheter, resolving the contradiction between joining strength and detachment risk.
Solution Approach 2:
The invention transitions from a single-dimensional protruding structure to a two-dimensional configuration combining both protruding portions and depressed portions at different locations. This dimensional expansion allows the structure to address detachment risks in multiple directions simultaneously, resolving the contradiction between strength enhancement and reliability.
2Reliability
If the outer layer is dragged in the distal end direction by a stenosis site or obstructed segment, then the outer layer may detach from the inner layer, but providing only a single-direction protruding portion does not prevent detachment in the proximal end direction
Solution Approach 1:
The invention divides the protective structure into two distinct segments: protruding portions at the proximal end for preventing distal detachment, and depressed portions at the distal end for preventing proximal detachment. This segmentation allows each structure to specialize in preventing detachment in its specific direction, achieving comprehensive bidirectional protection.
3Ease of operation
If the catheter is inserted through curved blood vessels, bile duct, or pancreatic duct, then the catheter must be flexible, but bending stress concentrates on the joining region, increasing the risk of outer layer detachment
Solution Approach 1:
The invention provides beforehand cushioning by creating depressed portions that act as stress-absorbing zones. These depressed portions are positioned in advance at locations where bending stress is likely to concentrate, cushioning the impact of bending forces before they can cause detachment, thus maintaining reliability during flexible insertion.
Data Source
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AI summary
[Problem] An object of the present invention is to provide a catheter and balloon catheter in which an outer layer is not easily detached from an inner layer even when the outer layer is dragged in the axis direction (the distal end and proximal end directions). [Solution] According to the catheter 1, the outer layer 40 has the protrusion part 50 in a location of the depressed portion 24 of the inner layer 10, the protrusion part 50 entering deeper than the reinforcement layer (coil body) 30 through the gap 25 and extending in the axis direction of the catheter 1. This can improve the joining strength between the inner layer 10 and the outer layer 40. Further, the risk of detachment of the outer layer 40 from the inner layer 10 can be reduced by virtue of the anchoring effect in which the protrusion part 50 of the outer layer 40 is caught in the reinforcement layer (coil body) 30 even when the outer layer 40 is dragged in the axis direction (the distal end and proximal end directions) at a stenosis site or an obstructed segment upon insertion of the catheter 1 into a blood vessel, bile duct, pancreatic duct, and the like.