Electrosurgical Generator Impedance Normalization
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Solution Overview
Problem
Existing electrosurgical systems lack effective monitoring and control mechanisms to prevent tissue damage during energy-based tissue treatment, particularly in achieving desired surgical effects like ablation and coagulation without causing unwanted charring or collateral damage.
Innovation Solution
An electrosurgical generator with sensor circuitry to measure and plot tissue or energy parameters, normalize these parameters with respect to treatment volume, and regulate output based on filtered and normalized plots to ensure precise control of energy delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If RF energy is applied to tissue to achieve ablation or coagulation, then surgical effect is improved, but unwanted charring or collateral damage occurs
Solution Approach 1:
The system continuously monitors tissue impedance during RF energy application and uses this feedback to dynamically adjust or terminate energy delivery. When impedance changes indicate completion of surgical effect or risk of damage, the system automatically responds to prevent harmful effects while maintaining surgical effectiveness.
Solution Approach 2:
The system monitors changes in tissue impedance parameters and uses these parameter changes to determine when to terminate energy delivery. By tracking impedance variations rather than relying on fixed time parameters, the system adapts to actual tissue response and prevents damage while ensuring surgical effect.
2Reliability
If electrosurgical energy is applied to coagulate blood vessels or tissue, then bleeding control is improved, but thermal spread to adjacent tissue occurs
Solution Approach 1:
The impedance monitoring system provides real-time feedback on tissue response to energy application. When impedance changes indicate that coagulation is complete or thermal spread is imminent, the system terminates or adjusts energy delivery to maintain bleeding control while preventing thermal damage to adjacent structures.
Solution Approach 2:
The system replaces time-based or fixed-parameter energy delivery with impedance-based dynamic control. By substituting mechanical timers or fixed settings with electrical impedance monitoring, the system achieves more precise control over energy application duration and intensity, preventing thermal spread while ensuring adequate coagulation.
3Manufacturing precision
If tissue impedance is measured to regulate electrosurgical power, then energy control is improved, but treatment volume normalization is insufficient
Solution Approach 1:
The system adds the dimension of treatment volume normalization to impedance-based energy control. By correlating impedance changes with treatment volume and normalizing the impedance plot accordingly, the system achieves more comprehensive control that accounts for both tissue response and spatial dimensions of energy delivery.
Solution Approach 2:
The system normalizes impedance parameters with respect to treatment volume, transforming raw impedance measurements into volume-corrected values. This parameter transformation enables better correlation between electrical measurements and actual treatment volume, improving both energy control precision and measurement accuracy.
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 solution enables intelligent termination of electrosurgical procedures, minimizing tissue damage by correlating tissue parameters with treatment volume dynamics, ensuring efficient energy application and preventing unintended energy drains or tissue damage.
Implementation Method 1
measuring at least one tissue or energy parameter... It is known that measuring the electrical impedance and changes thereof across the tissue at the surgical site provides a good indication of the state of desiccation or drying of the tissue
Implementation Method 2
Electrosurgery involves application of radio frequency electrical current to a surgical site to cut, ablate, coagulate or seal tissue... When the RF energy is provided between the return electrode and the inserted ablation electrode, RF current flows from the needle electrode through the body. Typically, the current density is very high near the tip of the needle electrode, which tends to heat and destroy surrounding issue
Implementation Method 3
Energy-based tissue treatment is well known in the art. Various types of energy (e.g., electrical, ohmic, resistive, ultrasonic, microwave, cryogenic, laser, etc.) are applied to tissue to achieve a desired result
Implementation Method 4
the controller is further configured to normalize the plot of the at least one tissue or energy parameter with respect to treatment volume... generating a plot of the at least one tissue or energy parameter including a plurality of tissue parameter values, wherein the controller is further configured to normalize the plot of the at least one tissue or energy parameter with respect to treatment volume
Data Source
AI summary
An electrosurgical generator for supplying electrosurgical energy to tissue includes sensor circuitry configured to measure at least one tissue or energy parameter and a controller configured to generate a plot of the at least one tissue or energy parameter including a plurality of tissue parameter values, wherein the controller is further configured to normalize the plot of the at least one tissue or energy parameter with respect to treatment volume.