Electrosurgical Jaw Angle Monitoring for Accurate Tissue Seal Detection
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Solution Overview
Problem
Contemporary electrosurgical instruments face challenges in accurately determining the quality of tissue sealing based solely on impedance measurements due to variables such as tissue composition, thickness, and temperature, leading to inconsistent seal detection.
Innovation Solution
The instrument employs a combination of non-therapeutic RF energy to measure tissue impedance and monitors jaw angle changes during seal cycles, using a controlled power delivery algorithm to adjust energy application based on impedance and jaw angle fluctuations, ensuring a complete seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If impedance measurement is used to determine tissue sealing quality, then seal detection capability is provided, but measurement precision deteriorates due to tissue composition, thickness, temperature, and other variable dependencies
Solution Approach 1:
The system continuously monitors jaw angle during the sealing process and uses this feedback to detect seal completion. The jaw angle sensor provides real-time data that is processed to identify the characteristic jaw angle increase that occurs when sealing is complete, enabling adaptive adjustment of the sealing cycle based on actual tissue response rather than relying on pre-set impedance thresholds that vary with tissue type
Solution Approach 2:
The patent replaces the electrical measurement system (impedance sensing) with a mechanical measurement system (jaw angle sensing) to determine seal completion. By monitoring the mechanical angle of the jaw assembly and detecting its characteristic increase during sealing, the system achieves more consistent and reliable seal detection that is independent of tissue electrical properties
2Reliability
If RF energy is applied to seal tissue, then sealing function is achieved, but thermal spread and tissue sticking occur as harmful side effects
Solution Approach 1:
The system uses periodic pulsed RF energy delivery rather than continuous energy application. The controller delivers energy in controlled pulses and monitors jaw angle between pulses, allowing the tissue to respond and the jaw angle to change without excessive heat accumulation. This periodic action achieves complete sealing while minimizing thermal spread and tissue sticking
Solution Approach 2:
The system uses real-time jaw angle monitoring to provide feedback that controls RF energy delivery. When the jaw angle increases indicating seal completion, the controller automatically terminates or adjusts energy delivery, preventing over-heating and associated harmful effects like thermal spread and tissue sticking while ensuring complete sealing
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 method provides precise detection of tissue sealing by correlating impedance and jaw angle changes, allowing for consistent and reliable sealing of tissues with minimal thermal spread and tissue sticking.
Implementation Method 1
controlling, with the processor, delivery of a therapeutic radio frequency (RF) energy signal to the plurality of electrodes
Implementation Method 2
measuring, with the processor, an impedance of the tissue
Data Source
AI summary
A surgical instrument includes an end effector which includes first and second jaws pivotably coupled together, and a plurality of electrodes. A processor is also included and configured to control delivery of an RF energy signal to the plurality of electrodes, monitor the impedance of the tissue, and monitor a jaw angle based on an angle of the first jaw and the second jaw relative to one another. Additionally, in response to identifying a first time period where the impedance is increasing, the greatest jaw angle monitored during the first time period is captured and the delivery of the therapeutic RF energy signal is adjusted. Further, in response to identifying a second time period where the impedance is increasing, the greatest jaw angle monitored during the second time period is captured. Whether the tissue has a predetermined tissue seal is then determined as a function of both captures.