Multipolar Cannula Thin-Film Insulation

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Solution Overview

Problem

Existing multipolar cannulas face challenges in compact design and efficient bioimpedance measurement due to bulky structures and complex electrode connections, limiting their ability to accurately determine tissue type and perform stimulation effectively.

Innovation Solution

A multipolar cannula design featuring a cannula tube with a conductive body as the first electrode and a thin-film applied electrically insulating layer and second electrodes, connected via a switch to a bioimpedance measuring unit, allowing for compact size and efficient electrical contacting, with an evaluation unit for signal processing and display.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional double-tube cannula structure is used with insulating plastic tubes, then electrical insulation between electrodes is achieved, but the cannula cross-section becomes bulky and large

Engineering Contradiction:
Improveelectrical insulationVSAvoidcannula cross-section
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent applies thin-film technology to create an electrically insulating layer with a thickness of only a few micrometers (preferably less than 1 micrometer) that coats the cannula tube body. This thin-film insulating layer replaces the bulky insulating plastic tubes of conventional designs, providing the necessary electrical insulation between the first electrode (cannula tube body) and second electrode while dramatically reducing the cannula's cross-sectional area and external dimensions.

Inventive Principle:
Principle #30Flexible shells and thin films

2Reliability

If electrodes extend over the entire length of the cannula tube, then electrical contact is maintained, but connection complexity increases

Engineering Contradiction:
Improveelectrical contactVSAvoidconnection complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the electrical connection function from the entire length of the electrode and concentrates it at a specific location. The first and second electrodes extend over the entire length of the cannula tube for reliable electrical contact with tissue, but their proximal ends are brought together at a single extraction point where a projection provides an electrically contactable connection. This allows simple external electrical contact without requiring complex connection mechanisms along the entire electrode length.

Inventive Principle:
Principle #2Taking out (Extraction)

3Area of stationary object

If thin-film processes are used for applying insulating layer and electrodes, then cannula dimensions are reduced, but manufacturing precision requirements increase

Engineering Contradiction:
Improvecannula cross-sectionVSAvoidfilm thickness control
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent employs thin-film deposition processes that precisely control the thickness parameters of the applied layers. The electrically insulating layer is deposited with a thickness of a few micrometers (preferably less than 1 micrometer), and the second electrode is applied as a thin film with comparable thickness control. These parameter-controlled thin-film processes enable the reduction of cannula cross-sectional dimensions while maintaining adequate electrical insulation and conductivity functions through optimized layer thickness parameters.

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

Enables precise bioimpedance measurements and tissue identification, along with stimulation capabilities, while reducing the cannula's external dimensions through thin-film technology and optimized electrode placement, enhancing user safety and handling.

Implementation Method 1

a layer that electrically insulates the first and the second electrode from each other

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Implementation Method 2

For a bioimpedance measurement, the electrical resistance between the free ends of the first and second electrodes is determined

Methodology Applied
Scientific EffectElectrical resistance measurement: Electrical Resistance

Implementation Method 3

the electrically insulating layer and at least the second electrode are applied to the cannula tube body using a thin-film process

Methodology Applied
Scientific EffectThin-film deposition: Deposition (physical)

Data Source

PatentEP3883641B1Multipolar cannula
Publication Date: 2024.06.12 PAJUNK GMBH MEDIZINTECH
  • EP3883641B1 patent drawingFigure 1~2

AI summary

Multi-polar cannula (10, 10') having a cannula tube (12) with a distal end (14) and a proximal end and with a first electrode (22) and at least one second electrode (24, 26, 28a, 28b, 28c), wherein the cannula tube (12) has a cannula tube body (18) and a layer (20) that electrically insulates the first and second electrodes (22, 24) from each other, wherein the distal end (14) of the cannula tube (12) has a distal tip (16), wherein the first electrode (22) is formed by the cannula tube body (18), and wherein the first electrode (22) and the second electrode (24) are connectable to a bioimpedance meter.