Ultrasonic Surgical Instrument Feedback Control
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Solution Overview
Problem
Existing ultrasonic cutting devices face challenges in maintaining optimal energy delivery to tissue due to frequency sensitivity and transmission losses, leading to variable blade movement and increased costs from precise frequency control, with handpieces and transducers often requiring replacement, causing mismatches in frequency-sensitive components.
Innovation Solution
A lightweight, hand-holdable ultrasonic cutting device with a feedback mechanism that adjusts ultrasonic waves in real-time based on load variations, using a microprocessor-controlled drive circuit, signal smoothing circuit, and sensing circuit to maintain resonance and optimize energy delivery, while allowing for the use of disposable components to reduce costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If precise frequency control is implemented to maintain resonance, then optimal blade movement and cutting performance is achieved, but device complexity and cost increase
Solution Approach 1:
The patent implements a feedback mechanism using a sensor to detect blade position and a controller to adjust the driving frequency in real-time, maintaining resonance without requiring complex precision frequency control systems. The feedback loop automatically compensates for frequency drift and load variations.
Solution Approach 2:
The system uses the existing ultrasonic vibration and mechanical resonance of the blade itself to generate the feedback signal, eliminating the need for external complex sensing systems. The blade's own mechanical response serves as the reference for frequency adjustment.
2Adaptability or versatility
If manual frequency adjustment is used to accommodate component replacements, then adaptability is improved, but operational time and precision are reduced
Solution Approach 1:
The automatic feedback control system continuously monitors blade resonance and adjusts frequency in real-time, eliminating the need for manual recalibration after component replacements. The system self-adapts to any blade or transducer configuration automatically.
Solution Approach 2:
The system dynamically adjusts the driving frequency based on real-time blade conditions and load variations, allowing seamless adaptation to different components without fixed frequency settings or manual intervention.
3Power
If high-voltage drive circuits are used to power piezoelectric transducers, then sufficient ultrasonic energy is produced, but transmission losses and electrical parasitics increase
Solution Approach 1:
The feedback mechanism optimizes the drive voltage and frequency to maintain resonance, minimizing energy losses. By operating at the resonant frequency, the system achieves maximum efficiency with reduced transmission losses and electrical parasitics.
Solution Approach 2:
The system dynamically changes the drive parameters (voltage and frequency) based on real-time feedback to optimize power delivery and minimize losses under varying load conditions and temperature differentials.
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 device ensures consistent and optimal energy delivery to tissue, reducing the need for precise frequency control and minimizing the impact of component replacements, thereby improving surgical performance and reducing costs by allowing for the use of disposable parts.
Implementation Method 1
the drive circuit 106 produces a high-voltage self-oscillating signal... The oscillating input to the transducer 110 causes the mechanical portion of the transducer 110 to move back and forth at a magnitude and frequency that sets up a resonance along the waveguide 114
Implementation Method 2
By placing a resonant wave along the length of the blade, high-speed longitudinal mechanical movement is produced at the end of the blade... Resonance results in optimal movement of the blade tip
Implementation Method 3
the mechanical vibrations transmitted to the end of the blade are very effective at cutting organic tissue and, simultaneously, coagulate the tissue using the heat energy produced by the ultrasonic frequencies
Data Source
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Figure 3
Figure 4~5
AI summary
An ultrasonic surgical instrument including an ultrasonic transmission member having a proximal end and a distal end is provided. The instrument also includes an ultrasonically-actuated cutting element having a tissue contacting surface and a clamp member supported adjacent to the cutting element for clamping tissue. The clamp member includes a sensing mechanism that senses load variations. A handle member located at the proximal end of the transmission member moves the clamp member relative to the cutting element. Also, a feedback mechanism is operatively coupled to the sensing mechanism that supplies information related to the load variations where the output of the tissue cutting element is adjusted based on the sensed load variations.