RF Medical Generator Impedance Control Algorithm
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Solution Overview
Problem
Existing electrosurgical generators face challenges in consistently and reliably controlling electrosurgical energy delivery due to initial tissue readings often being unreliable, leading to potential tissue damage and uneven vaporization during procedures.
Innovation Solution
A closed-loop control system with a sensor module and control module that continually monitor tissue impedance and reactance, disregarding initial unreliable readings and adjusting energy output based on real-time data to prevent rapid and uneven vaporization, using a processor and algorithm to match output with predetermined values from a map to ensure optimal tissue sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If initial tissue readings are used to control electrosurgical energy delivery, then the control system can start operation quickly, but the tissue sealing reliability deteriorates due to unreliable initial readings
Solution Approach 1:
The system performs preliminary measurements of tissue impedance before using it for control decisions. Initial readings are taken and stored, then a specified increase in impedance above a minimum value must be detected before the reading is accepted for controlling energy delivery. This preliminary verification step ensures reliability while maintaining relatively quick operation start.
Solution Approach 2:
The control system continuously monitors tissue impedance during the sealing process and uses feedback from impedance changes to adjust energy delivery. The system detects a specified increase in impedance above a minimum value as confirmation of reliable tissue contact and proper sealing progression, ensuring reliable tissue sealing through continuous feedback verification.
2Productivity
If high electrosurgical energy is delivered to seal tissue quickly, then productivity increases, but tissue damage worsens due to rapid and uneven vaporization
Solution Approach 1:
The system dynamically adjusts the electrosurgical energy delivery based on real-time tissue impedance measurements. Rather than delivering constant high energy, the controller modulates the energy output to match the tissue's changing impedance characteristics during the sealing process, preventing rapid and uneven vaporization while maintaining efficient sealing speed.
Solution Approach 2:
The control system changes the energy delivery parameters (voltage, current, power) based on measured tissue impedance values. By continuously monitoring impedance and adjusting energy parameters accordingly, the system optimizes the balance between sealing speed and tissue integrity, avoiding excessive energy that causes damage while maintaining productive sealing rates.
3Manufacturing precision
If tissue impedance monitoring is continuously performed to improve sealing control, then sealing precision improves, but device complexity increases
Solution Approach 1:
The system uses the tissue's own electrical impedance properties as the sensing mechanism, eliminating the need for separate physical sensors at the tissue interface. The electrosurgical electrodes themselves serve dual functions: delivering energy and measuring impedance. This self-service approach improves sealing precision through continuous monitoring while minimizing additional device complexity.
Solution Approach 2:
The electrodes serve multiple functions: they deliver electrosurgical energy for sealing and simultaneously measure tissue impedance for control feedback. This multi-functionality allows the system to achieve precise sealing control through continuous impedance monitoring without adding separate sensing components, thereby improving precision while limiting complexity increase.
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 effectively regulates electrosurgical energy delivery, ensuring reliable tissue sealing by continuously monitoring and adjusting parameters like current and voltage, reducing the risk of tissue damage and improving procedural consistency.
Implementation Method 1
measuring the electrical impedance and change 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
High frequency electrical energy, e.g., radio frequency (RF) energy, is produced by the electrosurgical generator and applied to the tissue by an electrosurgical tool
Implementation Method 3
The control system has a control algorithm that continually adjusts for changes in initial tissue conditions to enhance tissue fusion
Implementation Method 4
The alteration is based on the measured impedance across the tissue. The content of this patent is hereby incorporated by reference in its entirety
Data Source
AI summary
A system for performing an electrosurgical procedure at a surgical site is disclosed. The system includes a sensor configured to continually sense an electrical and/or a physical property of tissue at a surgical site and to generate a sensor signal as a function thereof. The system also includes a control module configured to process the sensor signal using a processor, an algorithm, and a map having one or more predetermined values. The control module is further configured to compare the sensor signal to a predetermined level to determine reliability of the sensor signal and to signal an electrosurgical generator in response to a reliable sensor signal such that the electrosurgical generator enters energy control mode, wherein the electrosurgical generator matches an output of the control signal with a predetermined value from the map.