Ultrasonic Instrument Blade Temperature Estimation via Resonance Frequency
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Solution Overview
Problem
Conventional laparoscopic surgical systems cannot estimate the temperature of an ultrasonic instrument's blade during the cooling cycle, posing a risk of thermal injuries to tissues due to residual heat.
Innovation Solution
A surgical system that estimates the temperature of an ultrasonic instrument by determining its resonance frequency while in a low-power state, using this information to display real-time temperature notifications to the operator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the ultrasonic instrument is deactivated during the cooling cycle to save energy, then power consumption is reduced, but temperature monitoring capability is lost
Solution Approach 1:
The system uses resonance frequency as an intermediary parameter to indirectly measure blade temperature. Instead of directly monitoring temperature by applying power, the system measures the resonance frequency of the blade, which changes predictably with temperature. This intermediary measurement allows temperature monitoring during the cooling cycle without consuming significant power.
Solution Approach 2:
The system replaces the electrical measurement method (applying power and measuring electrical characteristics) with a mechanical vibration method (measuring resonance frequency). By exciting the blade with minimal ultrasonic energy and measuring its resonant response, the system can determine temperature without the power consumption required for full heating operation.
2Measurement precision
If the blade is continuously monitored using electrical characteristics during heating, then temperature measurement precision is improved, but power consumption increases during cooling
Solution Approach 1:
The system measures resonance frequency as an intermediary that correlates with temperature. The resonance frequency is measured by applying minimal ultrasonic excitation and detecting the blade's vibrational response, providing temperature information without requiring the high power levels needed for heating and without the power consumption of continuous electrical characterization.
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
Enables real-time temperature monitoring of the ultrasonic instrument's blade during the cooling cycle, reducing the risk of thermal injuries and allowing operators to safely manipulate tissues.
Implementation Method 1
The tip may include a blade that reaches high temperatures (e.g., greater than 300° C.) during a 'heating' cycle in which the blade oscillates against a piece of tissue, thereby producing heat due to friction between the blade and the tissue during the oscillation.
Implementation Method 2
an ultrasonic instrument that uses ultrasonic vibration at its tip to rapidly generate heat for cutting and cauterizing tissue
Implementation Method 3
the system may determine a resonance frequency of the end effector (e.g., the blade while it vibrates over a lower excursion than needed to produce the heat). The system determines a temperature of the end effector based on the resonance frequency.
Data Source
AI summary
A method performed by a surgical system. The method determines that an ultrasonic instrument is in a low-power state The method determines a resonance frequency of an end effector of the ultrasonic instrument and determines a temperature of the end effector based on the resonance frequency. A notification is displayed on a display of the surgical system based on the temperature.