Electrosurgical Generator Voltage Sensing for Plasma Length Indication
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Solution Overview
Problem
Existing electrosurgical instruments lack a way to convey the length of the plasma to the practitioner even when the view of the treatment site and the plasma is restricted.
Innovation Solution
The electrosurgical generator is designed to power RF surgical instruments, generating a sequence of high-voltage pulses with a frequency exceeding 100 kHz, and includes a voltage detector to indicate the plasma length through visual, audible, or haptic signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the practitioner operates the electrosurgical generator to treat tissue, then the treatment function is achieved, but the practitioner cannot accurately estimate the plasma length when the view of the treatment site is restricted
Solution Approach 1:
The patent introduces an intermediary indicator device that mediates between the plasma generation system and the practitioner's perception. The indicator device converts the invisible plasma length into a visible signal, allowing the practitioner to accurately estimate plasma length without direct visual access to the treatment site.
Solution Approach 2:
The patent replaces the mechanical/visual estimation method with an electronic sensing and indication system. The voltage detector electronically measures plasma-related voltage, and the indicator device translates this into a perceptible signal, substituting direct visual observation with an electronic measurement system.
2Reliability
If no plasma length indication is provided, then the device complexity is low, but the treatment control and outcome are compromised
Solution Approach 1:
The patent implements a feedback mechanism where the voltage detector continuously monitors plasma-related voltage and the indicator device provides real-time information about plasma length to the practitioner. This feedback loop enables the practitioner to adjust operations to maintain optimal plasma length, improving treatment reliability.
Solution Approach 2:
The indicator device serves as an intermediary that bridges the gap between the complex internal electrical measurements and the practitioner's need for simple, reliable treatment control. It translates complex voltage measurements into intuitive indicators without adding significant operational complexity.
3Loss of information
If a voltage detector and indicator device are added to display plasma length, then the plasma length information becomes available to the practitioner, but the device complexity increases
Solution Approach 1:
The voltage detector serves multiple functions: it detects plasma length information, provides feedback for treatment control, and enables the indicator device to display relevant data. This multi-functionality reduces the need for separate dedicated components, minimizing the increase in device complexity.
Solution Approach 2:
The indicator device acts as an intermediary that efficiently communicates plasma length information without requiring complex display systems. By using simple perceptible signals (visual, acoustic, or haptic), it conveys essential information while adding minimal complexity to the overall system.
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 generator allows practitioners to adjust the plasma length accurately, ensuring appropriate distance between the instrument and tissue, thereby improving treatment outcomes.
Implementation Method 1
The converter module comprises a transformer with a primary winding and a secondary winding. While the secondary winding forms the output of the converter module, the primary winding is connected to an externally controlled electronic switch.
Implementation Method 2
A voltage detector is connected to this connection point and is configured to detect the voltage occurring at this connection point.
Implementation Method 3
An electric spark or plasma can be maintained between the tissue and the electrode, the length of which influences the physiological effect.
Implementation Method 4
An electrode for ionizing the gas jet is arranged in the channel, so that the instrument generates a plasma jet that exits the instrument in the distal direction.
Data Source
Figure 1~1a
Figure 2
Figure 3
AI summary
The generator (10) according to the invention contains at least one converter module with a transformer, the secondary winding of which is electrically connected to the electrode (17) of an instrument (12) and to a counter electrode (14). The primary winding of the transformer is connected to operating voltage on the one hand and to ground on the other hand via an electronic switch. The switch blocks periodically, whereby voltage pulses are generated in the secondary winding, which feed a spark or other plasma for the medical treatment of a patient. A voltage detector is used to display the plasma length. This detects the voltage occurring at the primary winding and displays it via an indicator device (24). The invention is based on the idea that the voltage occurring at the primary winding, in particular the peak voltage, characterizes the length of the generated plasma (16).The inventor has found that factors other than the plasma length are of minor importance in influencing the voltage measured at the primary coil.