Electrosurgical Pencil Electrode Coating for Low-Char Tissue Cutting

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Solution Overview

Problem

Existing electrosurgical pencils face issues with tissue adherence and char build-up on the electrode, leading to impaired precision and difficulty in making thin incisions due to high temperatures and frictional issues.

Innovation Solution

The electrode design features distinct surface roughness and coating configurations, with smoother edges for low friction and coated main surfaces for anti-stick properties, enhancing conductivity and reducing char formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the electrode surface is made smooth to reduce friction and facilitate movement through tissue, then ease of operation is improved, but tissue adherence and char build-up increase due to high temperatures

Engineering Contradiction:
Improveease of movement through tissueVSAvoidtissue adherence and char build-up
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The electrode surface is designed with different roughness characteristics in different regions: the cutting edge has a smooth surface (Ra ≤ 0.8 μm) to reduce friction and facilitate movement through tissue, while the main body surfaces have a rougher texture (Ra > 0.8 μm) to reduce tissue adherence and char build-up. This local differentiation allows each region to optimize its function without compromising the other.

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If the electrode edge is made rough to reduce tissue adherence, then tissue sticking is reduced, but friction and difficulty in making thin incisions increase

Engineering Contradiction:
Improvetissue stickingVSAvoidability to make thin incisions
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The electrode surface is designed with different roughness characteristics in different regions: the cutting edge has a smooth surface (Ra ≤ 0.8 μm) to reduce friction and facilitate movement through tissue, while the main body surfaces have a rougher texture (Ra > 0.8 μm) to reduce tissue adherence and char build-up. This local differentiation allows each region to optimize its function without compromising the other.

Inventive Principle:
Principle #3Local quality

3Object-affected harmful factors

If a surface coating is applied to the electrode to prevent tissue adherence, then anti-stick properties are improved, but bonding difficulties and manufacturing complexity increase

Engineering Contradiction:
Improvetissue adherenceVSAvoidbonding of surface coating
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The electrode surface is designed with different roughness characteristics in different regions: the cutting edge has a smooth surface (Ra ≤ 0.8 μm) to reduce friction and facilitate movement through tissue, while the main body surfaces have a rougher texture (Ra > 0.8 μm) to reduce tissue adherence and char build-up. This local differentiation allows each region to optimize its function without compromising the other.

Inventive Principle:
Principle #3Local quality

4Power

If the electrode operates at high temperatures for effective cutting and coagulation, then cutting and coagulation effectiveness is improved, but tissue char build-up and adherence worsen

Engineering Contradiction:
Improvecutting and coagulation effectivenessVSAvoidchar build-up
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

The electrode surface is designed with different roughness characteristics in different regions: the cutting edge has a smooth surface (Ra ≤ 0.8 μm) to reduce friction and facilitate movement through tissue, while the main body surfaces have a rougher texture (Ra > 0.8 μm) to reduce tissue adherence and char build-up. This local differentiation allows each region to optimize its function without compromising the other.

Inventive Principle:
Principle #3Local quality

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 electrode provides precise and smooth tissue cutting with reduced char build-up, improving surgical precision and efficiency by minimizing tissue adherence and facilitating easy electrode movement.

Implementation Method 1

the less rough surface can be un-coated which improves the ability to conduct electrical current, and the resulting electrode facilitates a precise cut with a sufficient electrical current and a smooth, low-frictional, movement through the tissue

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

it may be easier to bond a surface coating to a rough surface due to the increased surface area and the ability of the coating to grip the uneven surface

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 3

The electrode comprises an elongated body made of a conductive material... supplied with a high frequency, typically Radio Frequency (RF), alternating current signal by an RF source

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 4

The electrode is supplied with a high frequency, typically Radio Frequency (RF), alternating current signal... The RF source is typically called the Electro-Surgical Unit or ESU... configured for cutting or coagulation of tissue by electrosurgical energy

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP4427694B1An electrode for an electrosurgical pencil and a method of making an electrode
Publication Date: 2026.02.04 STRYKER EUROPEAN OPERATIONS LIMITED
  • EP4427694B1 patent drawingFigure 1~3
  • EP4427694B1 patent drawingFigure 4~7
  • EP4427694B1 patent drawingFigure 8~9

AI summary

An electrode for an electrosurgical pencil comprises an elongated body made of a conductive material and extending in an axial direction from a proximal end to a distal end. The proximal end is configured for engaging the electrosurgical pencil. The distal end forms a blade configured for cutting or coagulation of tissue by electrosurgical energy received from the electrosurgical pencil. The blade is defined by two main surface portions on opposite sides of an intermediate plane and joined by an edge extending through the intermediate plane. The edge comprises a smooth-part. The main surface portions have a first surface roughness. The smooth-part of the edge has a second surface roughness being lower than the first surface roughness. At least the main surface portions are covered by a surface coating. The smooth-part of the edge is un-coated. The first surface roughness is in a range of 2.0 Ra to 4.0 Ra, and the second surface roughness is less than 1.0 Ra. A method of making the electrode is also disclosed.