Articulating Ultrasonic Blade Impedance Control for Power Loss

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Solution Overview

Problem

Ultrasonic and electrosurgical devices require separate generators due to their 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 resulting in potential patient exposure to leakage currents.

Innovation Solution

An ultrasonic surgical system with a control circuit that determines the articulation angle of an articulatable ultrasonic blade, adjusts the complex impedance of the ultrasonic transducer, and compensates for power loss, using a processor to measure and compare complex impedance data points to reference patterns to assign an articulation angle and adjust power accordingly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate generators are used for ultrasonic and electrosurgical devices, then device-specific control and sensing needs are met, but device complexity increases and adaptability to interchangeable instruments is reduced

Engineering Contradiction:

Improvedevice-specific controlVSAvoidgenerator architecture

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a universal generator architecture that can operate with both ultrasonic and electrosurgical instruments through a single port. The system uses a waveform generator to produce different waveforms (sinusoidal for electrosurgical, square for ultrasonic) and a switch to route appropriate signals to the selected instrument type, eliminating the need for separate dedicated generators while maintaining reliable device-specific control

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If separate generators are used for ultrasonic and electrosurgical devices, then optimized control algorithms are available for each device type, but adaptability to disposable or interchangeable instruments is reduced

Engineering Contradiction:

Improvecontrol optimizationVSAvoidinstrument recognition

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system dynamically adapts its operation based on the connected instrument type. A detector identifies whether an ultrasonic or electrosurgical instrument is connected, and the control algorithm automatically adjusts accordingly - using impedance-based control for ultrasonic devices and voltage/current-based control for electrosurgical devices. This dynamic adaptation enables the single generator to optimize control for each device type while maintaining versatility with interchangeable instruments

Inventive Principle:

Principle #15Dynamics

3Reliability

If separate generators are used for ultrasonic and electrosurgical devices, then device-specific sensing and feedback needs are met, but patient safety is compromised due to potential leakage currents

Engineering Contradiction:

Improvesensing accuracyVSAvoidleakage currents

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an isolation transformer as an intermediary component between the generator circuits and the patient-connected instruments. This transformer provides galvanic isolation, blocking leakage currents from reaching the patient while allowing the passage of ultrasonic and electrosurgical energy. This enables the system to maintain accurate sensing and feedback for both device types while eliminating the harmful leakage current risk

Inventive Principle:

Principle #24Intermediary (Mediator)

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 surgical devices to maintain optimal performance and safety by compensating for power loss and ensuring accurate impedance measurements, reducing the risk of patient exposure to leakage currents and improving instrument recognition.

Implementation Method 1

Vibrating at high frequencies (e.g., 55,500 cycles per second), the ultrasonic blade denatures protein in the tissue to form a sticky coagulum

Methodology Applied

Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Implementation Method 2

An ultrasonic surgical device may comprise a handpiece containing an ultrasonic transducer... The ultrasonic transducer may be modeled as an equivalent circuit comprising a first branch having a static capacitance and a second 'motional' branch having a serially connected inductance, resistance and capacitance that define the electromechanical properties of a resonator

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS11986233B2Adjustment of complex impedance to compensate for lost power in an articulating ultrasonic device

Publication Date: 2024.05.21 CILAG GMBH INTERNATIONAL

AI summary

An ultrasonic device may include an electromechanical ultrasonic system defined by a predetermined resonant frequency, the electromechanical ultrasonic system having an ultrasonic transducer coupled to an ultrasonic blade. A method of compensating power delivered to the ultrasonic device may include determining an articulation angle of an articulatable ultrasonic blade coupled to the ultrasonic transducer, adjusting a complex impedance of the ultrasonic transducer to compensate for power lost as a function of the articulation angle, and adjusting, a power applied to the ultrasonic transducer based on the articulation angle. The ultrasonic device may include a generator and a control circuit configured to effect the method.