Electrosurgical Generator Impedance Trajectory Control
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Solution Overview
Problem
Current electrosurgical systems face challenges in precisely controlling the energy delivery to achieve effective tissue sealing, as they lack accurate real-time impedance measurement and adaptive energy control to match the desired impedance trajectory, leading to inconsistent and potentially incomplete tissue seals.
Innovation Solution
An electrosurgical system with impedance sensing circuitry and a processor that determines tissue reaction by measuring impedance and adjusting energy delivery to match a target impedance trajectory, ensuring the tissue impedance remains above a threshold for a predetermined period, incorporating temperature and fluid sensing for optimal energy application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electrosurgical energy is applied to tissue to achieve sealing, then tissue sealing is performed, but precise control of energy delivery to match desired impedance trajectory is difficult
Solution Approach 1:
The system continuously measures tissue impedance during electrosurgical energy delivery and uses this feedback to dynamically adjust the energy output. The controller compares real-time impedance measurements with target impedance values and modifies energy delivery to match the desired impedance trajectory, enabling precise control without requiring complex manual intervention.
Solution Approach 2:
The system changes the electrical parameters (voltage, current, power) of the electrosurgical energy delivery in real-time based on measured tissue impedance. By dynamically adjusting these parameters to follow a predefined impedance trajectory, the system achieves precise control over the sealing process while adapting to variations in tissue properties.
2Reliability
If energy delivery is increased to ensure complete tissue seal, then sealing effectiveness improves, but risk of tissue damage and incomplete seals increases
Solution Approach 1:
The system uses real-time impedance measurement as feedback to monitor tissue reaction to energy delivery. When impedance changes indicate the tissue has reached the desired sealing state, the system automatically adjusts or terminates energy delivery, preventing both insufficient sealing and excessive energy that could cause tissue damage.
Solution Approach 2:
The system dynamically adjusts energy delivery parameters during the sealing process based on real-time tissue response. Rather than using fixed high energy levels, the system adapts the energy application to match the tissue's changing impedance characteristics, ensuring complete seal while minimizing the risk of overheating or tissue damage.
3Measurement precision
If real-time impedance measurement is implemented, then energy delivery control precision improves, but system complexity and cost increase
Solution Approach 1:
The impedance sensing circuitry serves multiple functions: it measures tissue impedance for control purposes, monitors tissue reaction during sealing, and provides feedback for energy delivery adjustment. By making the sensing system multi-functional, the patent reduces the need for separate dedicated components and simplifies the overall system architecture.
Solution Approach 2:
The system uses the impedance measurement feedback loop to achieve precise energy delivery control. The controller continuously compares measured impedance with target values and adjusts energy delivery accordingly, enabling high measurement precision to be achieved through intelligent control rather than requiring overly complex hardware.
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 enables precise control of energy delivery, ensuring consistent and effective tissue sealing by maintaining tissue impedance within defined thresholds, reducing the risk of incomplete seals and improving the quality of the sealing process.
Implementation Method 1
Electrosurgery involves application of high radio frequency electrical current to a surgical site to cut, ablate, or coagulate tissue
Implementation Method 2
the system may transmit an initial interrogatory pulse for determining initial tissue impedance
Data Source
AI summary
An electrosurgical generator is disclosed. The generator includes an RF output stage configured to supply electrosurgical energy to tissue via at least one active electrode configured to apply electrosurgical energy to tissue; sensing circuitry configured to measure impedance of tissue; and a controller. The controller is configured to determine occurrence of a tissue reaction as a function of a minimum impedance value and a predetermined rise in impedance, wherein tissue reaction corresponds to a boiling point of tissue fluid; generate a target impedance trajectory as a function of measured impedance and desired rate of change based on the tissue reaction determination, wherein the target impedance trajectory includes a plurality of target impedance values; and drive tissue impedance along the target impedance trajectory by adjusting the output of the electrosurgical generator to substantially match tissue impedance to a corresponding target impedance for at least a predetermined minimum time period.