Dual-Frequency Electrosurgical Handpiece for Accurate Tissue Impedance Sensing
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Solution Overview
Problem
Current electrosurgical systems lack high accuracy in bipolar tissue sensing while delivering energy, as they either cannot determine individual tissue impedances in monopolar systems or have limited accuracy in bipolar systems.
Innovation Solution
An electrosurgery system that uses dual frequency signals, a diplexer, and current sensing circuits to combine and separate signals, allowing for accurate impedance measurement and power adjustment during treatment, enabling simultaneous treatment and impedance detection in both monopolar and bipolar modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If monopolar electrosurgical devices are used to deliver electrical current through tissue, then the current passes through the entire tissue between the electrode and return pad, but there is no way to determine the impedance of individual tissues in the treatment region
Solution Approach 1:
The patent segments the electrical current path into multiple parallel paths by using multiple return pads positioned at different locations. This allows the system to measure impedance at different tissue depths and locations independently, enabling determination of individual tissue impedances without requiring complex additional hardware.
Solution Approach 2:
The patent introduces multiple return pads as intermediary elements that facilitate impedance measurement. These return pads act as mediators between the electrode and the tissue, enabling the system to indirectly measure tissue impedance by analyzing current distribution patterns through the return pads without requiring direct tissue contact or complex sensing electrodes.
2Measurement precision
If bipolar systems are used to deliver electrical signal, then the impedance of the top region of the tissue can be determined, but the accuracy of measurement is limited
Solution Approach 1:
The patent makes the return pad system multi-functional by enabling it to serve both as a current collection point for electrosurgical treatment and as an impedance measurement sensor. The same return pads used for delivering electrical current also function as sensing elements for impedance measurement, eliminating the need for separate sensing electrodes and simplifying operation.
Solution Approach 2:
The patent implements feedback by continuously monitoring the current distribution patterns through the return pads during electrosurgical treatment and using this information to real-time adjust treatment parameters. The system uses the actual current measurements from multiple return pads to feedback-correct impedance calculations, improving measurement accuracy without adding complex manual measurement procedures.
3Measurement precision
If dual frequency signals are used to enable simultaneous treatment and sensing, then accurate impedance measurement is achieved, but the device complexity increases
Solution Approach 1:
The patent merges the treatment and sensing functions into a single integrated system by combining two frequency signals into one electrical current path. The electrosurgical electrode delivers a composite signal containing both treatment frequency (for coagulation) and sensing frequency (for impedance measurement) components, eliminating the need for separate treatment and sensing devices while achieving accurate impedance measurement.
Solution Approach 2:
The patent uses parameter changes by varying the frequency of the electrical signal to differentiate between treatment and sensing functions. The system switches between or combines different frequency parameters (e.g., 20-100 kHz for treatment and higher frequencies for sensing) to achieve both coagulation and accurate impedance measurement through the same electrical path, avoiding the need for complex multi-device systems.
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 system provides accurate tissue sensing and adjusts power delivery based on impedance, reducing the risk of overtreatment or undertreatment and enabling precise energy delivery during electrosurgery.
Implementation Method 1
a first signal generator configured to generate an electrical signal at a first frequency, a second signal generator configured to generate an electrical signal at a second frequency, and a diplexer configured to combine the electrical signal generated by the first signal generator and the electrical signal generated by the second signal generator to create a combined signal
Implementation Method 2
a first current sensing circuit configured to measure a quantity of the electrical signal at the first frequency at the return pad; and a second current sensing circuit configured to measure a quantity of the electrical signal at the second frequency at the other of the other one of the at least two tips
Data Source
AI summary
Systems described herein include a two-tip handpiece that delivers current from two sources at two different frequencies. Signals at different frequencies are absorbed differently in the body. Accordingly, both monopolar and bipolar systems using this two tip handpiece and dual-frequency signal can detect impedance (or other frequency dependent characteristics) of the target tissue at the tips while delivering treatment, which was not possible or practical using conventional systems.