Double Percutaneous Coaxial Needle for Stable Electrostimulation

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Solution Overview

Problem

The existing electrostimulation devices with double percutaneous coaxial needles face issues with the axial stroke of guide and reciprocal retention means being limited by the presence of an insulated electric conductor, leading to potential device malfunctions and complicating the manufacturing process.

Innovation Solution

The device features a cannula and counter-cannula with telescopically connected tubular bodies made of electrically conductive materials, where the counter-cannula is fixed with a thermocouple means and an insulated electric conductor, allowing for stable axial sliding and positioning, and a mounting body made of insulating material to ensure proper electrical connection and ease of manufacturing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the support body of the cannula is lengthened to increase the number of stable relative positions of the counter-cannula with respect to the cannula, then the axial stroke and positioning capability are improved, but the risk of undesired erroneous positioning of the electrical conductor increases, leading to device malfunctions

Engineering Contradiction:
Improvepositioning precisionVSAvoiddevice reliability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The support body is divided into two separate support bodies: a first support body for the cannula and a second support body for the counter-cannula. This segmentation allows each support body to be independently designed and optimized, preventing the electrical conductor from being subjected to excessive axial movements that could cause erroneous positioning or jamming, while still providing multiple stable relative positions through the telescopic connection between the two support bodies.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first support body acts as an intermediary structure that houses the electrical conductor and provides a stable reference frame. By separating the support functions and using the first support body as an intermediary, the electrical conductor is protected from the axial movements that occur when the counter-cannula is advanced or retracted, eliminating the risk of conductor positioning errors.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the insulated electric conductor is placed through the cavity of the cannula support body, then electrical connection is achieved, but the structure and manufacturing process are complicated

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

Solution Approach 1:

The support structure is segmented into two separate support bodies, each with its own cavity. The first support body contains the electrical conductor in its cavity, providing a dedicated pathway for the conductor that simplifies the overall structure. This segmentation eliminates the need for the conductor to pass through a single complex support body, reducing manufacturing complexity while maintaining reliable electrical connection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The electrical conductor and its support function are extracted from the cannula support structure and placed in a dedicated first support body. This extraction simplifies the design by giving the conductor its own dedicated housing, making the manufacturing process easier and reducing the overall structural complexity while ensuring reliable electrical connection.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of operation

If the guide and reciprocal retention means are designed to allow successive steps of manual advancement and retraction, then operational flexibility is improved, but the axial stroke is limited by the presence of the insulated electric conductor

Engineering Contradiction:
Improveoperational flexibilityVSAvoidaxial stroke
Core Design Contradiction:
Ease of operationVSLength of moving object

Solution Approach 1:

The support system is segmented into two independent support bodies that can move relative to each other axially. This segmentation decouples the axial movement of the counter-cannula from the electrical conductor, allowing the counter-cannula to have a large axial stroke for advanced manipulation while the conductor remains stably positioned in the first support body, thus maintaining operational flexibility without stroke limitations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first support body serves as an intermediary that remains relatively stationary while the second support body moves axially relative to it. This intermediary structure allows the counter-cannula to achieve full axial stroke for operational flexibility, while the conductor housed in the first support body is not subjected to movement limitations, resolving the contradiction between stroke length and operational flexibility.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

This configuration enables stable and reliable operation of the device, facilitating correct positioning and reducing the risk of malfunctions, while simplifying the manufacturing process.

Implementation Method 1

The counter-cannula is fixed with a thermocouple means

Methodology Applied
Scientific EffectThermocouple: Thermocouple

Implementation Method 2

The counter-cannula is fixed with a thermocouple means and an insulated electric conductor

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

Cannula and counter-cannula are made of electrically conductive material, for example steel, and are coupled to each other with possibility of relative axial sliding

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 4

the cannula is completely isolated externally by an electrically and thermally insulating coating

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Implementation Method 5

the cannula is completely isolated externally by an electrically and thermally insulating coating

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP4448081B1Electrostimulation device with a double percutaneous coaxial needle and process for manufacturing the same
Publication Date: 2025.10.08 FORINO LUCIANO
  • EP4448081B1 patent drawingFigure 1
  • EP4448081B1 patent drawingFigure 2
  • EP4448081B1 patent drawingFigure 3~4

AI summary

Electrostimulation device (10) with a double percutaneous coaxial needle, comprising: - two tubular bodies (11.10, 11.20), in plastic material, hereinafter referred to respectively as cannula support (11.10) and counter-cannula support (11.20), wherein the cannula support (11.10) and the counter-cannula support (11.20) are telescopically connected with the possibility of relative axial sliding; - a cannula needle (11.1) and a counter-cannula needle (11.2), hereinafter referred to respectively as cannula (11.1) and counter-cannula (11.2), axially perforated. The cannula (11.1) is supported fixed and coaxial with respect to the cannula support (11.10) and the counter-cannula (11.2) is supported fixed and coaxial with respect to the counter-cannula support (11.20) and the counter-cannula (11.2) is inserted in a coaxial arrangement and is electrically insulated with respect to the cannula (11.1), with the possibility of relative axial sliding. The cannula support (11.10) is, at least partially, included within the counter-cannula support (11.20) with the possibility of relative axial sliding. The invention provides also a process for manufacturing said electrostimulation device (10) with a double percutaneous needle.