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EP-4736782-A2 - SYSTEM FOR CONTROLLING AN ULTRASONIC TOOL

EP4736782A2EP 4736782 A2EP4736782 A2EP 4736782A2EP-4736782-A2

Abstract

A console (22) and a method for controlling an ultrasonic surgical tool (20) to reduce presence of a harmonic signal (44) are described. The console (22) and method are configured to drive the ultrasonic surgical tool (20) with a first drive signal (40), acquire a frequency characteristic of the harmonic signal (44) in the ultrasonic surgical tool resulting from application of the first drive signal (40) to the ultrasonic surgical tool (20), generate a cancellation signal (70) based on the acquired frequency characteristic of the harmonic signal (44), combine the cancellation signal (70) with the first drive signal (40) to produce a second drive signal (80), the second drive signal (80) being sinusoidal, and the cancellation signal (70) being configured to introduce additional frequency components into the second drive signal (80), and drive the ultrasonic surgical tool (20) with the second drive signal (80) such that the presence of the harmonic signal (44) at the acquired frequency characteristic that results from driving the ultrasonic surgical tool (20) with the second drive signal (80) is reduced relative to presence of the harmonic signal (44) at the acquired frequency characteristic that results from driving the ultrasonic surgical tool (20) with the first drive signal (40), wherein the additional frequency components in the second drive signal (80) effect simultaneous control of the tip (26) over two different resonant modes.

Inventors

  • DOWNEY, ADAM DARWIN

Assignees

  • Stryker Corporation

Dates

Publication Date
20260506
Application Date
20160714

Claims (15)

  1. A console (22) for controlling an ultrasonic surgical tool (20) to reduce presence of a harmonic signal (44), the console (22) configured to: drive the ultrasonic surgical tool (20) with a first drive signal (40); acquire a frequency characteristic of the harmonic signal (44) in the ultrasonic surgical tool resulting from application of the first drive signal (40) to the ultrasonic surgical tool (20); generate a cancellation signal (70) based on the acquired frequency characteristic of the harmonic signal (44); combine the cancellation signal (70) with the first drive signal (40) to produce a second drive signal (80), the second drive signal (80) being sinusoidal, and the cancellation signal (70) being configured to introduce additional frequency components into the second drive signal (80); and drive the ultrasonic surgical tool (20) with the second drive signal (80) such that the presence of the harmonic signal (44) at the acquired frequency characteristic that results from driving the ultrasonic surgical tool (20) with the second drive signal (80) is reduced relative to presence of the harmonic signal (44) at the acquired frequency characteristic that results from driving the ultrasonic surgical tool (20) with the first drive signal (40), wherein the additional frequency components in the second drive signal (80) effect simultaneous control of a tip (26) of the ultrasonic surgical tool (20) over two different resonant modes.
  2. The console (22) of claim 1 configured to implement non-linear, simultaneous control of the tip (26) of the ultrasonic surgical tool (20) over two different resonant modes.
  3. The console (22) of claim 1 configured to acquire an amplitude characteristic of the harmonic signal (44) resulting from driving the ultrasonic surgical tool (20) with the first drive signal (40) and generate the cancellation signal (70) based on the acquired frequency characteristic, the acquired amplitude characteristic, and a predefined default phase characteristic.
  4. The console (22) of claim 1 configured to acquire a phase characteristic of the harmonic signal (44) resulting from driving the ultrasonic surgical tool (20) with the first drive signal (40) and generate the cancellation signal (70) based on the acquired frequency characteristic, the acquired phase characteristic, and a predefined default amplitude characteristic.
  5. The console (22) of claim 1 configured to acquire the frequency characteristic of the harmonic signal (44) by generating current and voltage samples relating to the first drive signal (40), wherein the frequency characteristic of the harmonic signal (44) is present in the generated current and voltage samples.
  6. The console (22) of claim 5 configured to acquire the frequency characteristic of the harmonic signal (44) by analyzing a fast-Fourier transform of the generated current and voltage samples to determine the frequency characteristic of the harmonic signal.
  7. The console (22) of claim 1 configured to acquire a phase characteristic of the harmonic signal (44) and generate the cancellation signal (70) with a phase characteristic being shifted by any odd multiple of 180 degrees in relation to the acquired phase characteristic of the harmonic signal (44).
  8. The console (22) of claim 1 configured to acquire an amplitude characteristic of the harmonic signal (44), and to generate the cancellation signal (70) with an amplitude characteristic being equal to or greater than the amplitude characteristic of the harmonic signal (44); and, optionally, configured to generate the cancellation signal (70) with the amplitude characteristic being twice the amplitude characteristic of the harmonic signal (44).
  9. A method of controlling an ultrasonic surgical tool (20) to reduce presence of a harmonic signal (44), the method comprising: driving the ultrasonic surgical tool (20) with a first drive signal (40); acquiring a frequency characteristic of the harmonic signal (44) in the ultrasonic surgical tool (20) resulting from driving the ultrasonic surgical tool (20) with the first drive signal (40); generating a cancellation signal (70) based on the acquired frequency characteristic of the harmonic signal (44); combining the cancellation signal (70) with the first drive signal (40) to produce a second drive signal (80), the second drive signal (80) being sinusoidal, and the cancellation signal (70) being configured to introduce additional frequency components into the second drive signal (80); and driving the ultrasonic surgical tool (20) with the second drive signal (80) such that the presence of the harmonic signal (44) at the acquired frequency characteristic that results from driving the ultrasonic surgical tool (20) with the second drive signal (40) is reduced relative to presence of the harmonic signal (44) at the acquired frequency characteristic that results from driving the ultrasonic surgical tool (20) with the first drive signal (40), wherein the additional frequency components in the second drive signal (80) effect simultaneous control of a tip (26) of the surgical tool (20) over two different resonant modes.
  10. The method of claim 9 implementing simultaneous control of the tip (26) of the ultrasonic surgical tool (20) over two different resonant modes non-linear.
  11. The method of claim 9, comprising acquiring an amplitude characteristic of the harmonic signal (44) resulting from driving the ultrasonic surgical tool (20) with the first drive signal (40) and generating the cancellation signal (70) based on the acquired frequency characteristic, the acquired amplitude characteristic, and a predefined default phase characteristic.
  12. The method of claim 9, comprising acquiring a phase characteristic of the harmonic signal (44) resulting from driving the ultrasonic surgical tool (20) with the first drive signal (40) and generating the cancellation signal (70) based on the acquired frequency characteristic, the acquired phase characteristic, and a predefined default amplitude characteristic.
  13. The method of claim 9, comprising acquiring the frequency characteristic of the harmonic signal (44) by generating current and voltage samples relating to the first drive signal (40), wherein the frequency characteristic of the harmonic signal (44) is present in the generated current and voltage samples; and, optionally, further comprising acquiring the frequency characteristic of the harmonic signal (44) by analyzing a fast-Fourier transform of the generated current and voltage samples to determine the frequency characteristic of the harmonic signal (44).
  14. The method of claim 9, comprising acquiring phase characteristic of the harmonic signal (44) and generating the cancellation signal (70) with a phase characteristic being shifted by any odd multiple of 180 degrees in relation to the phase characteristic of the harmonic signal (44).
  15. The method of claim 9, comprising acquiring an amplitude characteristic of the harmonic signal (44) and generating the cancellation signal (70) with an amplitude characteristic being equal to or greater than the amplitude characteristic of the harmonic signal (44); and, optionally, comprising generating the cancellation signal (70) with the amplitude characteristic being twice the amplitude characteristic of the harmonic signal (44).

Description

CROSS-REFERENCE TO RELATED APPLICATION(S) The present application claims the benefit of U.S. Provisional Patent Application No. 62/192,838, filed July 15, 2015, the entire disclosure of which is hereby incorporated by reference. TECHNICAL FIELD The present invention relates generally to a system and method for controlling an ultrasonic surgical tool, and more specifically, reducing presence of an unwanted signal resulting from operation of the surgical tool. BACKGROUND Ultrasonic surgical tools, such as ultrasonic aspirators, typically include a handpiece containing an ultrasonic transducer and a tip coupled to the transducer to interface with tissue. A console or generator is connected to the surgical tool to control the surgical tool by outputting specific drive signals to the transducer. The surgical tool is for use in open or minimally invasive surgical procedures to provide coagulation of tissue, and the like. For many tip/transducer combinations, the transducer is driven with a sinusoidal drive signal that has a frequency component. The ultrasonic tip is typically designed to operate at the frequency component with only a single dominant vibration mode (e.g. longitudinal). Vibrational motion of the tip is directly related to what in industry is referred to as mechanical current. The tip operates at resonance when mechanical current is in phase with the handpiece voltage. Since the transducer is driven with a sinusoidal signal with a frequency component, the current to the handpiece consequently is sinusoidal with a frequency component. Some conventional ultrasonic tip and handpiece combinations naturally exhibit a harmonic signal or signals causing harmonic distortion. Such harmonic signals may cause the current to the handpiece to exhibit a variable phase shift relative to the voltage to the handpiece. In conventional systems, significant harmonic distortion is present in both the voltage and current to the handpiece. The harmonic signals cause the voltage and current to the handpiece to exhibit additional frequency components, such as harmonics, causing the voltage and current waveforms to be impurely sinusoidal. Such harmonics produce unwanted vibrations of the tip. The unwanted vibrations have a negative impact on the performance of the surgical tool. For example, such unwanted vibrations increase the stress on the tip and create unwanted excessive heat in certain locations. Such unwanted excessive heat reduces life of the tip due to fatigue and thermal heating of surrounding tissue. Furthermore, the system must operate at a higher voltage to overcome additional loading effects of the acoustical properties of the tip changing due to an increased temperature resulting from the excessive heat. In turn, performance of the controlling console is reduced because the unwanted vibration energy is sent back to the console from the handpiece. SUMMARY Accordingly, the present invention provides a console for controlling an ultrasonic surgical tool to reduce presence of a harmonic signal resulting from driving the ultrasonic surgical tool. The console is configured to apply a first drive signal to the ultrasonic surgical tool. The console acquires a characteristic of the harmonic signal resulting from application of the first drive signal to the ultrasonic surgical tool. The console generates a cancellation signal based on the characteristic of the harmonic signal. The console combines the first drive signal and the cancellation signal to produce a second drive signal, wherein the second drive signal is sinusoidal. The console is configured to apply the second drive signal to the ultrasonic surgical tool such that presence of the harmonic signal resulting from application of the second drive signal is reduced relative to presence of the harmonic signal resulting from application of the first drive signal. The present invention also provides a method of controlling the ultrasonic surgical tool to reduce presence of the harmonic signal resulting from driving the ultrasonic surgical tool. The method includes driving the ultrasonic surgical tool with the first drive signal. The characteristic of the harmonic signal resulting from driving the ultrasonic surgical tool with the first drive signal is acquired. The method includes generating the cancellation signal based on the characteristic of the harmonic signal. The first drive signal and the cancellation signal are combined to produce the second drive signal wherein the second drive signal is sinusoidal. The method includes driving the ultrasonic surgical tool with the second drive signal such that presence of the harmonic signal resulting from driving the ultrasonic surgical tool with the second drive signal is reduced relative to presence of the harmonic signal resulting from driving the ultrasonic surgical tool with the first drive signal. In addition, the present invention provides a method of controlling the ultrasonic surgical tool to reduce presence of th