Dual-Material Guide Tube for Abrasion-Resistant Cannula Deflection

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Solution Overview

Problem

Existing medical instruments with guide tubes made of metal or plastic face issues such as high manufacturing costs and risk of damage to the guide channel, leading to potential clogging or particle contamination, especially when the cannula is advanced and deflected within the body canal.

Innovation Solution

A medical device with a guide tube featuring a dual-material construction, where the proximal section is made of plastic and the distal section is made of a harder material like stainless steel, and includes design elements such as a rotatable handle, adjustable stops, and a flexible cannula for safe and precise insertion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the guide tube is made of plastic, then manufacturing costs are reduced, but the distal tip of the cannula can damage the guide channel and scrape off plastic particles

Engineering Contradiction:
Improvemanufacturing costVSAvoidguide channel integrity
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The guide tube is constructed with different materials in different sections: the proximal section is made of plastic for cost-effectiveness, while the distal section is made of a harder, more abrasion-resistant material to prevent damage from the cannula tip. This local differentiation of material properties resolves the contradiction between manufacturing cost and reliability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The guide tube employs a composite structure combining plastic and harder material sections. This composite construction allows the tube to benefit from the low cost and flexibility of plastic while incorporating the abrasion resistance of harder materials where needed, thus resolving the contradiction between manufacturing cost and guide channel integrity.

Inventive Principle:
Principle #40Composite materials

2Reliability

If the guide tube is made of metal, then abrasion resistance is improved, but manufacturing costs increase

Engineering Contradiction:
Improveabrasion resistanceVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Instead of making the entire guide tube from expensive metal, only the distal section that requires high abrasion resistance is made of harder material. The proximal section remains plastic, reducing overall manufacturing costs while maintaining necessary durability where required.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The guide tube uses a composite construction combining metal or harder material with plastic. This allows the benefits of metal (abrasion resistance) to be applied only where necessary, rather than throughout the entire tube, thus resolving the contradiction between reliability and manufacturing cost.

Inventive Principle:
Principle #40Composite materials

3Ease of operation

If the cannula tip is advanced into the guide channel, then the insertion angle is increased, but the risk of damage to the guide channel increases

Engineering Contradiction:
Improveinsertion angleVSAvoidguide channel damage risk
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The distal section of the guide channel is pre-equipped with a harder, more abrasion-resistant material before the cannula is inserted. This beforehand reinforcement protects the guide channel from damage when the cannula tip is advanced and deflected, allowing the beneficial increased insertion angle to be achieved without the harmful damage risk.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentEP4580720B1Medical instrument
Publication Date: 2026.04.22 GAISELMANN THOMAS
  • EP4580720B1 patent drawingFigure 1
  • EP4580720B1 patent drawingFigure 2~3
  • EP4580720B1 patent drawingFigure 4~5

AI summary

The invention relates to a medical instrument (10) comprising a guide tube (20) which can be inserted into a corporeal duct of a patient, wherein the guide tube (20) has an open proximal end (21) and a closed distal end (22) as well as an inner axial guide channel (24) which originates from the proximal end (21) and which leads to an opening (26) arranged laterally on the circumference of the guide tube (20) such that an elastically flexible cannula (51) can be inserted into the guide channel (24) through the proximal end (21) and the distal tip (52) of the cannula exits laterally through the opening (26), said tip being bent away from the longitudinal axis (A) of the guide tube (20), when the cannula is advanced in the guide channel (24). The guide tube (20) is rotatably arranged on a handle part (30) about the longitudinal axis (A) of the guide tube, and the guide channel (24) has a first section (25a) adjoining the proximal end (21) and a second section (25b) adjoining the opening (26). The wall (25) of the guide channel (24) is made of plastic in the first section (25a) and a material with a greater degree of hardness than the plastic of the first section (25a) in the second section (25b).