Ultrasonic Blade Temperature Control via Resonant Frequency Feedback
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Solution Overview
Problem
Current ultrasonic surgical instruments face challenges in accurately determining the state of the ultrasonic surgical instrument during tissue interaction, particularly in adjusting power based on temperature and resonant frequency changes, which affects the efficiency and precision of tissue cutting and coagulation.
Innovation Solution
An ultrasonic electromechanical system comprising an ultrasonic blade, a transducer, and a control circuit that determines the natural and oscillation resonant frequencies, and adjusts power based on temperature measurements to maintain optimal cutting and coagulation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the ultrasonic blade operates at high power to improve cutting efficiency, then the cutting speed increases, but the blade temperature rises excessively causing tissue damage and reduced precision
Solution Approach 1:
The system continuously monitors the resonant frequency of the ultrasonic blade and uses this feedback to adjust the drive power. When frequency deviation indicates temperature rise, the system automatically reduces power to maintain optimal operating conditions and prevent excessive heating.
Solution Approach 2:
The system dynamically adjusts operating parameters (power level, frequency) based on real-time blade state. By changing these parameters in response to temperature and frequency measurements, the system maintains cutting efficiency while preventing overheating.
2Measurement precision
If the system continuously monitors resonant frequency and temperature to maintain precision, then the control accuracy improves, but the device complexity increases
Solution Approach 1:
The ultrasonic blade itself provides the measurement signal through its resonant frequency, which naturally changes with temperature and load conditions. This self-diagnostic capability eliminates the need for separate complex sensing systems, achieving precise state monitoring through the blade's inherent physical properties.
Solution Approach 2:
The system replaces complex mechanical temperature sensors and frequency detectors with electrical impedance and resonant frequency measurements. This substitution simplifies the measurement system while maintaining high precision in state determination.
3Reliability
If the ultrasonic blade oscillates against tissue to perform surgical functions, then the surgical effectiveness improves, but the resonant frequency shifts making control difficult
Solution Approach 1:
The system transitions from static frequency control to dynamic frequency tracking. The drive frequency continuously adapts to match the blade's instantaneous resonant frequency, which changes during tissue interaction. This dynamic approach maintains optimal energy transfer and surgical effectiveness despite frequency shifts.
Solution Approach 2:
The system performs preliminary frequency scanning to identify the resonant frequency before full power operation begins. This preliminary action establishes the baseline frequency and prepares the control system for subsequent dynamic adjustments during tissue engagement.
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 ensures precise control over the ultrasonic surgical instrument, enhancing the efficiency and safety of surgical procedures by accurately determining the instrument's state and adjusting power accordingly, thereby improving tissue cutting and coagulation outcomes.
Implementation Method 1
an ultrasonic transducer acoustically coupled to the ultrasonic blade... The ultrasonic transducer is configured to ultrasonically oscillate the ultrasonic blade in response to a drive signal
Implementation Method 2
The control circuit is configured to determine a temperature of the ultrasonic blade... enhancing the efficiency and safety of surgical procedures by accurately determining the instrument's state
Implementation Method 3
The control circuit is configured to determine a first resonant frequency of the ultrasonic electromechanical system, determine a second resonant frequency of the ultrasonic electromechanical system as the ultrasonic blade oscillates against a tissue
Data Source
AI summary
An ultrasonic electromechanical system for an ultrasonic surgical instrument may include an ultrasonic blade, a clamp arm disposed opposite the ultrasonic blade, an ultrasonic transducer configured to oscillate the ultrasonic blade in response to a drive signal, and a control circuit coupled to the ultrasonic transducer. The control circuit can be configured to determine a temperature of the ultrasonic blade, increase an amount of power of the drive signal when the temperature of the ultrasonic blade is less than a first predetermined value, and decrease the amount of power of the drive signal when the temperature of the ultrasonic blade is greater than a second predetermined value. The second predetermined value may be greater than the first predetermined value. An ultrasonic generator connectable to the ultrasonic electromechanical system may include the control circuit.