RF Tissue Classification Control for Fine Dissection Energy Delivery
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Solution Overview
Problem
Ultrasonic and electrosurgical devices require separate generators and user interfaces due to their unique drive signals, feedback needs, and capacitive coupling issues, limiting their ability to recognize instrument configurations and optimize control, especially in noisy environments.
Innovation Solution
A modular communication hub and generator module that integrates ultrasonic and electrosurgical instruments, employing adaptive algorithms to identify tissue type and adjust device parameters, and a unified user interface for both types, with capacitive isolation to prevent patient exposure to leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate generators are used for ultrasonic and electrosurgical devices, then each device can have optimized control and sensing, but the system complexity increases and instrument interchangeability is limited
Solution Approach 1:
The patent combines ultrasonic and electrosurgical drive signals, sensing circuits, and control algorithms into a single multifunctional generator. The generator uses a single RF amplifier and switching network to produce both ultrasonic (55.5 kHz) and electrosurgical (30-100 kHz) signals, while integrating impedance sensing and classification algorithms that work for both instrument types, thereby reducing system complexity while maintaining optimized control for each instrument type
Solution Approach 2:
The generator is designed with universal sensing and control capabilities that can recognize and optimize control for both ultrasonic and electrosurgical instruments. The impedance sensing circuit and classification algorithm automatically identify the instrument type and adjust control parameters accordingly, enabling a single generator to perform multiple functions with optimized control for each instrument type
2Adaptability or versatility
If electromagnetic interference and harmonic distortion are present, then the generator can operate in noisy environments, but impedance measurement accuracy decreases and patient safety is compromised
Solution Approach 1:
The patent implements continuous impedance sensing with feedback control that monitors the RF amplifier output and adjusts drive signal parameters to compensate for electromagnetic interference and harmonic distortion. The system measures impedance in real-time and uses classification algorithms to detect tissue contact and instrument state, adjusting control parameters to maintain measurement accuracy even in noisy surgical environments
Solution Approach 2:
The patent introduces an intermediary classification algorithm that processes impedance measurements and distinguishes between valid tissue contact signals and noise-induced artifacts. The algorithm analyzes impedance patterns, contact duration, and signal characteristics to filter out electromagnetic interference and harmonic distortion, providing accurate tissue contact detection and instrument state recognition despite noisy environmental conditions
Data Source
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AI summary
A method of controlling the application of energy to a radio frequency (RF) instrument based on a surgical technique may include activating the instrument for a first period T1, during which time a portion of an end effector contacts a tissue, plotting at least two electrical parameters associated with the tissue to classify an amount of the end effector in contact with the tissue, applying a classification algorithm to classify the amount of the end effector in contact with the tissue, and applying an amount of energy to the end effector based on the amount of the end effector in contact with the tissue. The parameters may include a minimum impedance of the tissue and an amount of time that the impedance slope is ∼0. The end effector may contact the tissue with a tip end or with an entire surface.