Bipolar Electrosurgical Instrument Impedance Control
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Solution Overview
Problem
Existing bipolar electrosurgical instruments do not provide optimal transfer of electrical power to tissue, resulting in suboptimal tissue sealing times during surgical procedures.
Innovation Solution
A bipolar electrosurgical system with a controller that manages radio frequency energy delivery to electrodes on movable jaw members, adjusting voltage levels and impedance measurements to optimize sealing, including an initialisation stage, heating stage, sealing stage, and completion stage, with monitoring for short circuits and open circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing bipolar electrosurgical instruments are used, then the structure is simple and easy to operate, but the electrical power transfer to tissue is not optimal resulting in longer sealing times
Solution Approach 1:
The patent implements dynamic control of radio frequency energy delivery through multiple stages (initialisation, heating, sealing, completion) with real-time impedance monitoring. The controller dynamically adjusts voltage levels and power delivery based on measured tissue impedance, transitioning from static to dynamic operation to optimize sealing speed while managing device complexity.
Solution Approach 2:
The system incorporates impedance sensing between the first and second electrodes that provides real-time feedback to the controller. This feedback mechanism allows the controller to monitor tissue state and adjust RF energy delivery accordingly, improving sealing efficiency through closed-loop control while adding measurement and control components.
2Productivity
If higher power is applied to reduce sealing time, then sealing speed improves, but risk of tissue damage and harmful effects increases
Solution Approach 1:
The system dynamically adjusts power delivery through staged voltage profiles rather than applying constant high power. The controller transitions through initialization, heating, sealing, and completion stages with varying voltage levels, optimizing sealing speed while preventing tissue damage through controlled power escalation and termination.
Solution Approach 2:
Real-time impedance monitoring provides feedback on tissue state during RF delivery. The controller uses this feedback to detect when sealing is complete and to prevent excessive energy delivery that could cause tissue damage, thereby reducing harmful effects while maintaining efficient sealing speed.
Solution Approach 3:
The initialization stage performs preliminary low-power conditioning before the main sealing process. This preliminary action prepares the tissue for subsequent higher-power sealing while minimizing initial damage risk, and establishes baseline impedance measurements for safe power delivery during the sealing stage.
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 achieves improved tissue sealing by dynamically controlling radio frequency energy delivery, ensuring efficient and consistent sealing of tissues, reducing sealing times and enhancing the reliability of the sealing process.
Implementation Method 1
sealing is typically achieved using application of radio frequency energy delivered to the tissue being sealed by electrodes mounted on the opposed jaws of the instrument
Implementation Method 2
a radio frequency signal generator operable to supply a radio frequency signal to the first and second electrodes via the power cable
Implementation Method 3
to measure an impedance between the first and second electrodes during supply of the controlled voltage level
Data Source
AI summary
A bipolar surgical instrument comprises a body first and second opposed jaws located at the distal end of a shaft, the first jaw being movable with respect to the second jaw between an open position in which the first and second jaws are spaced apart from one another, and a closed position in which the first and second jaws are adjacent one another. The first and second elongate jaw members have respective first and second electrodes. A controller is operable to determine a boiling point for tissue between the jaws using a measure of impedance therebetween.