Neutral Electrode Testing Device with Layered Skin Simulation
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Solution Overview
Problem
Current devices for testing neutral electrodes in electrosurgery fail to simulate the edge effect caused by volume conduction in skin layers and muscle fibers, leading to inaccurate temperature distribution and thermal load estimation.
Innovation Solution
A device with a measuring surface of multiple electrodes connected to an equivalent resistance circuit representing skin layers, including the epidermis, corium, and hypodermis, using temperature sensors and reactive resistances to simulate the directional and edge effects of current distribution, allowing for precise temperature measurement and simulation of skin properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple equivalent resistance circuit is used to simulate skin properties, then the device complexity is reduced, but the measurement precision of temperature distribution and thermal load estimation deteriorates due to inability to simulate edge effects
Solution Approach 1:
The skin is segmented into multiple distinct layers (epidermis, corium, hypodermis), each represented by separate equivalent resistance circuits with specific resistance values. This segmentation allows the device to simulate the complex current distribution and edge effects that occur in real skin tissue, thereby improving measurement precision without requiring an overly complex overall device structure.
Solution Approach 2:
The patent uses parameter changes by assigning different resistance values to different skin layers based on their electrical properties. The equivalent resistance circuits are configured with specific resistance values (e.g., epidermis: 1000-5000 ohms, corium: 100-500 ohms, hypodermis: 50-200 ohms) to accurately represent the electrical characteristics of each layer, enabling precise simulation of temperature distribution and thermal load.
2Manufacturing precision
If homogeneous resistance is used across the measuring surface, then the manufacturing precision is improved, but the reliability of thermal load estimation deteriorates due to inability to simulate directional current distribution
Solution Approach 1:
The patent applies local quality by assigning different resistance characteristics to different regions and layers of the skin model. Each skin layer has its own equivalent resistance circuit with locally optimized resistance values that reflect the actual electrical properties of that specific tissue layer. This local differentiation enables accurate simulation of directional current distribution and edge effects, thereby improving the reliability of thermal load estimation.
Solution Approach 2:
The patent transitions from a two-dimensional homogeneous surface model to a three-dimensional multi-layered model by adding the vertical dimension of skin layers. Each layer is represented with its own resistance characteristics, creating a volumetric equivalent circuit model that accurately captures the directional current distribution through different tissue depths, thus improving reliability without compromising manufacturing precision.
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 device accurately simulates the temperature distribution and edge effects, providing a more realistic estimation of thermal load and current concentration, thus improving the testing of neutral electrodes for electrosurgery.
Implementation Method 1
the temperature increase thus generated is measured and results in measuring values comparable with those obtained with a human subject
Implementation Method 2
each measuring electrode of the measuring surface is connected to an equivalent resistance circuit representing at least one layer of the human skin
Implementation Method 3
which equivalent resistance circuit is in thermal contact with at least one temperature sensor
Data Source
AI summary
The invention relates to a device for testing a neutral electrode (1) for use in electrosurgery, comprising a measuring surface (25) which is formed by a plurality of measuring electrodes (20), whereon the neutral electrode (1) is applied. Each measuring electrode (20) of the measuring surface (25) is connected to a replacement resistance circuit (70) representing at least one layer of the human skin, which is placed in thermal contact with at least one temperature sensor (90). At least one resistance of the replacement-resistance circuit (70) is formed by means of a blind resistance (54).