Electrosurgical Impedance Control for Tissue Dehydration Detection
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Solution Overview
Problem
Conventional electrosurgical apparatuses fail to reliably detect the dehydration state of biological tissues, leading to weak tissue joining forces and prolonged surgery times, as they are not designed to differentiate between tissue dehydration and vapor formation, which can result in unnecessary prolonged high-frequency power output.
Innovation Solution
The electrosurgical system employs a control portion that monitors impedance changes, switching from constant power to constant voltage control and stopping high-frequency power output when a second sharp impedance rise is detected, indicating tissue dehydration, to ensure effective tissue joining without burning or prolonged operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-frequency power is supplied for a long period to ensure strong tissue joining, then joining force is improved, but surgery time is unnecessarily prolonged
Solution Approach 1:
The control portion continuously monitors tissue impedance during high-frequency power supply and uses this feedback to detect the dehydration state. When impedance rises above a threshold indicating dehydration, the system automatically stops power supply, eliminating the need for prolonged operation while ensuring adequate joining force.
Solution Approach 2:
The system monitors changes in tissue impedance as a key parameter to determine the dehydration state. By detecting when impedance rises above a predetermined threshold, the system identifies the optimal stopping point for high-frequency power supply, balancing joining strength with surgical efficiency.
2Loss of time
If high-frequency power is stopped when impedance increases, then surgery time is reduced, but tissue may not be fully dehydrated resulting in weak joining force
Solution Approach 1:
The system uses impedance threshold detection to determine when tissue dehydration is sufficient. By setting an appropriate threshold value, the system stops power supply at the optimal moment when joining force is maximized, avoiding both premature termination and excessive prolongation.
Solution Approach 2:
The patent replaces subjective surgical judgment with objective electrical impedance measurement. The control portion automatically interprets impedance values to determine dehydration state, eliminating reliance on surgeon experience while achieving consistent, optimal stopping points.
3Reliability
If conventional impedance monitoring is used to detect dehydration, then power supply can be stopped, but vapor formation cannot be differentiated from tissue dehydration
Solution Approach 1:
The system monitors the rate and magnitude of impedance change rather than absolute impedance values. A sharp rise in impedance above a threshold indicates true dehydration, while gradual changes reflect vapor formation. This differential approach uses simple threshold comparison to distinguish between the two states.
Solution Approach 2:
The control portion acts as an intermediary that interprets raw impedance data and translates it into meaningful dehydration state information. By processing impedance changes through logical thresholds and timing criteria, the system converts ambiguous electrical measurements into reliable control decisions.
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 approach allows for strong and efficient tissue joining by accurately detecting dehydration states, preventing tissue burning and reducing surgery time by ensuring the high-frequency power is stopped once tissues are dehydrated, thus maintaining a strong joining force.
Implementation Method 1
the tissue impedance is once decreased and then, as the tissue dries, air enters the tissue, which causes sudden increase of the impedance
Implementation Method 2
a high frequency power from the high frequency power source is supplied to the treatment instrument to thereby dissect or join the tissue that is the treatment target
Data Source
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AI summary
A high-frequency cauterization power source is an electrosurgical apparatus for joining biological tissues. The electrosurgical apparatus includes a high frequency power supply portion for supplying a high frequency power that is applied to biological tissues; a detection portion for detecting a voltage and a current of a high frequency power that is output from the high frequency power supply portion; an impedance calculating portion that calculates an impedance between a pair of electrodes 3a supplied with the high frequency power and grasping biological tissue based on respective values for voltage and current detected at the detection portion; and a control portion that controls so as to substantially stop supply of the high frequency power from the high frequency power supply portion based on whether or not an increase greater than or equal to a predetermined value in the impedance that is calculated at the tissue impedance calculating portion occurs two times.