Flexible Distal Catheter Assembly for Large-Angle Vessel Insertion

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Solution Overview

Problem

Conventional catheter assemblies face issues where the catheter distal end can get caught by the blood vessel back wall, especially at large puncture angles, leading to difficulty in insertion and potential damage to the blood vessel wall.

Innovation Solution

A catheter assembly with a flexible portion at its distal end, more flexible than the catheter body, is designed to prevent the distal end from being caught by the blood vessel back wall, featuring a flexible portion with a gradual change in rigidity and a close contact with the inner needle to facilitate flashback confirmation and reduce insertion resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional catheter with uniform rigidity is used, then the catheter maintains structural stability, but the catheter distal end may be caught by the blood vessel back wall at large puncture angles

Engineering Contradiction:

Improvecatheter insertion reliabilityVSAvoidcatheter distal end catching by blood vessel wall

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The catheter is designed with different rigidity characteristics at different locations: the proximal portion maintains higher rigidity for structural stability, while the distal portion incorporates a flexible portion with lower rigidity to prevent catching by the blood vessel wall. This local differentiation of mechanical properties resolves the contradiction between maintaining overall catheter stability and preventing distal end catching.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The flexible portion at the distal end allows the catheter to dynamically adapt its shape during insertion. When the catheter encounters the blood vessel back wall at large puncture angles, the flexible portion can bend and deform to avoid catching, while the rest of the catheter maintains its structural integrity. This dynamic response capability resolves the contradiction between rigidity and flexibility.

Inventive Principle:

Principle #15Dynamics

2Object-affected harmful factors

If the catheter is made more flexible to prevent catching, then the catheter can navigate large puncture angles, but the catheter may become difficult to advance and control

Engineering Contradiction:

Improvecatheter distal end catching by blood vessel wallVSAvoidcatheter advancement and control

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

Only the distal portion of the catheter is made flexible while the proximal portion maintains higher rigidity. This localized flexibility allows the distal end to navigate large puncture angles without affecting the overall controllability and ease of advancement of the catheter body.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The catheter is segmented into distinct regions with different mechanical properties: a proximal portion for structural support and control, and a distal flexible portion for navigating puncture challenges. This segmentation allows each segment to perform its specific function optimally without compromising the other.

Inventive Principle:

Principle #1Segmentation

3Productivity

If a sharp needle tip is used to puncture the blood vessel, then puncture efficiency is improved, but the risk of damaging the blood vessel wall increases

Engineering Contradiction:

Improvepuncture efficiencyVSAvoidblood vessel wall damage

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The flexible portion at the distal end of the catheter acts as a cushioning element that is positioned ahead of the sharp needle tip during insertion. When the needle tip contacts the blood vessel wall, the flexible portion can deform to absorb impact and reduce the risk of wall damage, while still allowing efficient puncture.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The catheter system changes the mechanical parameters along its length, with the flexible portion having lower stiffness and higher elasticity compared to the rigid needle and catheter body. This parameter gradient allows the system to maintain puncture efficiency while reducing wall damage risk through localized energy absorption.

Inventive Principle:

Principle #35Parameter changes

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 flexible distal portion effectively prevents the catheter from being caught by the blood vessel wall, ensuring easy insertion, reducing the risk of vessel damage, and allowing for clear flashback confirmation during use.

Implementation Method 1

a flexible portion that is provided at a distal portion of the catheter body, includes a most distal portion of the catheter, and is more flexible than the catheter body

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS12629499B2Catheter assembly

Publication Date: 2026.05.19 TERUMO KK

AI summary

A method of making a catheter includes: performing an extrusion molding process while changing extrusion speeds of materials that are extruded, so as to form a catheter that includes: a catheter body, and a flexible portion that is provided at a distal portion of the catheter body, forms a most distal portion of the catheter, and is more flexible than the catheter body.