Ultrasonic Instrument Temperature Estimation via Resonance Hysteresis
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Solution Overview
Problem
There is no mechanism in existing laparoscopic surgical systems to notify operators of the temperature of ultrasonic instruments, making it difficult for them to determine when the blade has sufficiently cooled to avoid thermal injuries to sensitive tissue during repeated activation and deactivation cycles.
Innovation Solution
A surgical system that estimates the temperature of an ultrasonic instrument by determining the change in resonance frequency and applying it to a hysteresis model to output a notification, allowing for closed-loop temperature control and maintaining a desired temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the ultrasonic instrument is repeatedly activated for performing surgical tasks, then the productivity of the surgical procedure is improved, but the blade temperature increases causing thermal injury risk to sensitive tissue
Solution Approach 1:
The system continuously monitors blade temperature during repeated activation cycles and provides real-time feedback to the operator. When the blade temperature exceeds a safe threshold, the system generates an alert notification, enabling the operator to adjust usage patterns and avoid thermal injury to sensitive tissue while maintaining high productivity through optimized task sequencing
Solution Approach 2:
The system performs preliminary temperature assessment before allowing repeated activation of the ultrasonic instrument. By predicting temperature rise based on usage patterns and providing advance warning, the system enables proactive management of blade temperature, preventing thermal injury before it occurs while maintaining surgical workflow efficiency
2Object-affected harmful factors
If the blade is deactivated to cool down, then the thermal injury risk is reduced, but the time required for surgical procedures increases
Solution Approach 1:
Instead of requiring complete cooling of the blade between surgical tasks, the system implements partial cooling by monitoring temperature and allowing resumption of surgical tasks once temperature drops below the safety threshold. This approach reduces unnecessary cooling time while maintaining safety, enabling the blade to cool only to the extent needed to prevent thermal injury
Solution Approach 2:
The system implements periodic temperature monitoring and alternating between heating and cooling phases during surgical procedures. By rhythmically managing blade temperature through monitored cooling periods followed by controlled reactivation, the system minimizes total cooling time while ensuring thermal safety throughout the procedure
3Device complexity
If the operator manually estimates blade temperature, then no additional system complexity is introduced, but the measurement precision is insufficient to accurately determine safe operating conditions
Solution Approach 1:
The system replaces manual operator estimation with automated electronic temperature sensing and processing. A temperature sensor integrated with the ultrasonic instrument electronically measures blade temperature, and a processor automatically compares readings against safety thresholds, generating objective and precise temperature assessment without requiring additional complex mechanical components
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 accurate temperature estimation and notification, preventing thermal injuries by ensuring the ultrasonic instrument cools down safely before further tissue manipulation, enhancing safety and efficiency in minimally invasive surgeries.
Implementation Method 1
an ultrasonic instrument that uses ultrasonic vibration at its tip to rapidly generate heat for cutting and cauterizing tissue
Implementation Method 2
producing heat due to friction between the blade and the tissue during the oscillation
Implementation Method 3
the blade begins to cool down from the high temperature at which the blade was used to perform the surgical task
Implementation Method 4
determining a change in resonance frequency of the end effector while the ultrasonic instrument is either in a high-power state
Data Source
AI summary
A method performed by a surgical system that includes an ultrasonic instrument with an end effector. The method determines a change in resonance frequency of the end effector while the ultrasonic instrument is either in 1) a high-power state in which the ultrasonic instrument draws a first current to cause the end effector to produce heat or 2) a low-power state in which the ultrasonic instrument draws a second current, which is less than the first current that does not cause the end effector to produce heat. The method determines a temperature of the end effector by applying the change in resonance frequency to a hysteresis model that includes a hysteretic relationship between changes in resonance frequency of the end effector and corresponding temperatures of the end effector, and outputs a notification based on the temperature.