Smart Ultrasonic Blade Vessel Detection Using Complex Impedance
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Solution Overview
Problem
Ultrasonic and electrosurgical devices require different generators due to unique drive signal, sensing, and feedback needs, leading to limitations in recognizing instrument configurations and optimizing control and diagnostic processes, especially when instruments are disposable or interchangeable, and there are concerns about patient exposure to leakage current due to capacitive coupling.
Innovation Solution
An ultrasonic device with an electromechanical system that includes an ultrasonic transducer coupled to an ultrasonic blade, where a processor or control circuit applies energy, measures complex impedance, compares it to a reference pattern, and determines if the blade is contacting a vessel, adjusting power levels and providing warnings through visual, auditory, or tactile feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ultrasonic and electrosurgical devices use separate dedicated generators, then device reliability and performance are optimized, but device complexity and system integration increase
Solution Approach 1:
The patent implements a single generator capable of providing both ultrasonic and electrosurgical energy through a unified control system. The generator includes separate power amplifiers for ultrasonic and RF energy, with a controller that can selectively activate appropriate energy delivery modes based on the connected instrument type, thereby consolidating multiple dedicated generators into one multi-functional device while maintaining optimized performance for each modality
Solution Approach 2:
The patent merges ultrasonic and electrosurgical energy delivery systems into a single integrated generator. The control circuitry combines impedance sensing, tissue classification algorithms, and energy delivery control for both ultrasonic and RF modalities within one system architecture, reducing the number of separate devices while preserving the specialized performance characteristics of each energy type
2Ease of operation
If disposable or interchangeable instruments are used, then ease of operation and sterility are improved, but the ability to recognize instrument configurations and optimize control decreases
Solution Approach 1:
The patent implements an impedance sensing system that continuously monitors the electrical impedance between the instrument electrodes and tissue. The controller analyzes impedance magnitude and phase information to automatically detect instrument type, tissue contact status, and operational conditions. This feedback mechanism enables the generator to adapt control parameters and energy delivery characteristics based on the specific disposable or interchangeable instrument connected, thereby maintaining optimized control despite instrument variability
Solution Approach 2:
The patent utilizes changes in electrical impedance parameters to detect and adapt to different instrument configurations. The system measures impedance magnitude and phase angle, and uses these parameter variations to identify instrument type, tissue contact state, and operational mode. By monitoring parameter changes in real-time, the system automatically adjusts control algorithms and energy delivery settings to match the specific instrument and tissue conditions
3Measurement precision
If complex impedance measurement and real-time analysis are implemented, then measurement precision and surgical precision are improved, but device complexity and processing requirements increase
Solution Approach 1:
The patent replaces complex mechanical sensing systems with electrical impedance measurement. Instead of using mechanical sensors to detect tissue contact and instrument status, the system uses electrical impedance spectroscopy to infer tissue properties, contact force, and instrument position. This substitution simplifies the physical sensor architecture while providing rich diagnostic information through electrical parameter analysis
Solution Approach 2:
The patent enables the ultrasonic transducer and RF electrodes to serve dual functions: energy delivery and sensing. The same electrical components used for energy delivery also provide the impedance measurement capability, eliminating the need for separate sensing hardware. The system uses the inherent electrical properties of the energy delivery components to perform tissue characterization and contact detection, thereby reducing overall device complexity while maintaining measurement precision
4Ease of manufacture
If capacitive coupling is present in the generator architecture, then ease of manufacture is improved, but patient exposure to leakage current increases
Solution Approach 1:
The patent introduces an isolation transformer as an intermediary component in the generator architecture. The transformer provides galvanic isolation between the capacitive coupling elements and the patient-connected circuits. By placing the isolation transformer in the signal path, the system maintains the manufacturing simplicity of capacitive coupling while blocking the transmission of leakage current to the patient, thereby resolving the safety hazard without sacrificing ease of manufacture
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 adaptive control of ultrasonic blades based on tissue contact, reducing the risk of patient exposure to harmful currents and improving surgical precision by optimizing energy delivery and feedback mechanisms.
Implementation Method 1
an ultrasonic transducer coupled to an ultrasonic blade, where a processor or control circuit applies energy
Implementation Method 2
Vibrating at high frequencies (e.g., 55,500 cycles per second), the ultrasonic blade denatures protein in the tissue to form a sticky coagulum
Implementation Method 3
measuring, by the processor or control circuit, a complex impedance of the ultrasonic transducer
Data Source
AI summary
An ultrasonic device may include an electromechanical ultrasonic system defined by a predetermined resonant frequency and include an ultrasonic transducer coupled to an ultrasonic blade. A method of delivering energy to the device may include applying energy to the blade at a first power level via the transducer coupled to the blade, measuring a complex impedance of the transducer, receiving a complex impedance feedback data point, comparing the complex impedance feedback data point to a reference complex impedance characteristic pattern, and determining that the blade is contacting a vessel based on the comparison. The method may also include disabling the power applied to the transducer and switching to a lower power level. The method may further include generating a warning that the blade is contacting a vessel, such as a light or a sound. An ultrasonic surgical instrument may effect the method.