Ultrasonic Dissector Frequency Response for Temperature and Tissue Detection
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Solution Overview
Problem
Existing ultrasonic surgical instruments face challenges in accurately detecting temperature and identifying tissue type, relying on costly scanning mechanisms or limited field-of-view methods like thermocouples and optical imaging, which can complicate surgeries and hinder optimal surgical outcomes.
Innovation Solution
An ultrasonic surgical apparatus with a first oscillating structure and a microcontroller that uses a bridge circuit to detect mechanical motion, determining temperature and tissue type through a second oscillating structure's electrical signal, and issuing visual, audible, or tactile signals when exceeding pre-set temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If thermocouples are used for temperature detection, then temperature measurement capability is provided, but device complexity increases due to separate attachment and multiple wires required
Solution Approach 1:
The patent combines the temperature sensing function with the existing ultrasonic blade structure by utilizing the blade's own electrical properties (impedance, resonant frequency) as the sensing mechanism, eliminating the need for separate thermocouple attachments and their associated wiring
Solution Approach 2:
The ultrasonic blade serves dual purposes: it performs cutting functions and simultaneously provides temperature sensing through monitoring its own electrical characteristics, requiring no external sensing components
2Measurement precision
If scanning mechanisms like ultrasound, CAT, or MRI are used for tissue identification, then tissue detection capability is provided, but cost increases significantly
Solution Approach 1:
The patent uses inexpensive electrical impedance measurement circuits and signal processing capabilities already present in standard ultrasonic generators to identify tissue types, replacing costly scanning mechanisms with affordable electrical sensing
Solution Approach 2:
The existing ultrasonic generator and control circuits are made multi-functional by using them not only for driving the ultrasonic blade but also for sensing tissue properties through electrical impedance and frequency response measurements
3Measurement precision
If optical imaging through laparoscope is used for tissue detection, then tissue visualization is provided, but field of view is limited
Solution Approach 1:
The patent replaces optical imaging mechanisms with electrical field-based sensing through impedance measurement, allowing tissue identification without line-of-sight requirements and expanding the effective detection field beyond what optical systems can provide
4Measurement precision
If thermocouples are attached to the ultrasonic surgical instrument, then temperature monitoring is enabled, but ease of operation decreases due to attachment requirements
Solution Approach 1:
The ultrasonic blade monitors its own temperature through electrical impedance measurements without requiring external attachment, making the system easier to operate by eliminating setup steps
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 precise temperature monitoring and tissue differentiation, ensuring optimal surgical performance by providing real-time feedback and maintaining resonance, thus enhancing surgical precision and safety.
Implementation Method 1
Ultrasonic instruments are effectively used in the treatment of many medical conditions... Cutting instruments that utilize ultrasonic waves generate vibrations with an ultrasonic transducer along a longitudinal axis of a cutting blade
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
Implementation Method 3
These instruments are advantageous because 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
Implementation Method 4
a bridge circuit, detecting the mechanical motion of the first oscillating structure and outputting a signal representative of the mechanical motion
Implementation Method 5
a second oscillating structure integrally formed within a portion of the first oscillating structure, the second oscillating structure outputting an electrical signal, and a microcontroller receiving the signal output by the bridge circuit and output by the second oscillating structure, the microcontroller determining an instantaneous frequency... and determining the temperature of the second oscillating structure based on a the comparison
Data Source
AI summary
An ultrasonic surgical apparatus including a first signal generator outputting a drive signal at a predetermined voltage and frequency, a first oscillating structure receiving the drive signal and oscillating at the frequency of the drive signal, and a bridge circuit, detecting the mechanical motion of the first oscillating structure and outputting a signal representative of the mechanical motion. The apparatus also includes a second oscillating structure integrally formed within a portion of the first oscillating structure, the second oscillating structure outputting an electrical signal, and a microcontroller receiving the signal output by the bridge circuit and output by the second oscillating structure, the microcontroller determining an instantaneous frequency at which the first oscillating structure is oscillating based on the received signal, comparing the electrical signal from the second oscillating structure with a known signal value and determining the temperature of the second oscillating structure based on a the comparison.