TEMPERATURE ESTIMATION AND TISSUE DETECTION OF AN ULTRASONIC DISSECTOR FROM FREQUENCY RESPONSE MONITORING

• US 20200132638A1
• Filed: 12/24/2019
• Published: 04/30/2020
• Est. Priority Date: 06/11/2012
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Covidien LP (Medtronic Plc)
• Inventors: Ross, Anthony B., Van Tol, David J., Price, David S.
• Granted Patent: US 10,955,387 B2
• Time in Patent Office: Days
• CPC Class Codes: A61B 17/320092 with additional movable means for clamping or cutting tissue, e.g. with a pivoting jaw
• CPC Class Codes: A61B 2017/0003 of parts of the instruments
• CPC Class Codes: A61B 2017/00075 Motion
• CPC Class Codes: A61B 2017/00084 Temperature
• CPC Class Codes: A61B 2017/00106 ultrasonic
• CPC Class Codes: A61B 2017/00734 battery operated
• CPC Class Codes: A61B 2017/320094 additional movable means performing clamping operation
• CPC Class Codes: A61B 2017/320095 with sealing or cauterizing means
• CPC Class Codes: G01N 29/44 Processing the detected response signal , e.g. electronic circuits specially adapted therefor digital signal processing per se G06F17/00

Abstract

An ultrasonic surgical apparatus and method, the apparatus including a signal generator outputting a drive signal having a frequency, an 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 oscillating structure and outputting a signal representative of the mechanical motion. The ultrasonic surgical apparatus also includes a microcontroller receiving the signal output by the bridge circuit, the microcontroller determining an instantaneous frequency at which the oscillating structure is oscillating based on the received signal, and determining a frequency adjustment necessary to maintain the oscillating structure oscillating at its resonance frequency, the microcontroller further determining the quality (Q value) of the signal received from the bridge circuit and determining material type contacting the oscillating structure.

Claims

1-10. -10. (canceled)

11. An ultrasonic surgical instrument, comprising:

an ultrasonic transducer;

an ultrasonic waveguide extending from the ultrasonic transducer;

an ultrasonic blade disposed at a distal end of the ultrasonic waveguide, wherein the ultrasonic transducer, the ultrasonic waveguide, and the ultrasonic blade cooperate to define an oscillating structure; and

a control circuit coupled to a memory, the control circuit configured to;

determine an actual resonant frequency of the oscillating structure;

retrieve, from the memory, a reference resonant frequency of the oscillating ultrasonic structure; and

determine a temperature of the ultrasonic blade based on a difference between the actual resonant frequency and the reference resonant frequency.

12. The ultrasonic surgical instrument according to claim 11, wherein the reference resonant frequency is a resonant frequency of the ultrasonic blade at room temperature.

13. The ultrasonic surgical instrument according to claim 11, wherein the reference resonant frequency is stored in the memory during manufacturing.

14. The ultrasonic surgical instrument according to claim 11, wherein the reference resonant frequency is stored in the memory upon connection of the ultrasonic waveguide with the ultrasonic transducer.

15. The ultrasonic surgical instrument according to claim 11, the actual resonant frequency is determined based upon an impedance of the oscillating structure.

16. The ultrasonic surgical instrument according to claim 11, further comprising a drive circuit configured to provide a drive signal to the ultrasonic transducer to drive the oscillating structure at the actual resonant frequency, wherein the actual resonant frequency is determined based upon a motional voltage of the drive signal.

17. The ultrasonic surgical instrument according to claim 11, wherein the control circuit is further configured to compare the determined temperature to a temperature threshold and output an alert where the determined temperature is above the temperature threshold.

18. The ultrasonic surgical instrument according to claim 11, further comprising a clamp arm pivotable relative to the ultrasonic blade to clamp tissue between the clamp arm and the ultrasonic blade.

19. The ultrasonic surgical instrument according to claim 11, further comprising a handpiece supporting the oscillating structure.

20. The ultrasonic surgical instrument according to claim 19, further comprising:

an ultrasonic drive signal generator supported by the handpiece, the ultrasonic drive signal generator configured to generate a drive signal to drive the oscillating structure; and

a battery supported by the handpiece, the battery configured to power the ultrasonic drive signal generator.

21. The ultrasonic surgical instrument according to claim 11, wherein the ultrasonic transducer includes a plurality of piezoelectric elements.

22. A method for estimating a temperature of an ultrasonic surgical blade, the method comprising:

driving an oscillating structure including an ultrasonic transducer, an ultrasonic waveguide extending from the ultrasonic transducer, and an ultrasonic blade disposed at a distal end of the ultrasonic waveguide;

determining an actual resonant frequency of the oscillating structure;

retrieving, from a memory, a reference resonant frequency of the oscillating structure; and

determine a temperature of the ultrasonic blade based on a difference between the actual resonant frequency and the reference resonant frequency.

23. The method according to claim 22, wherein the reference resonant frequency is a resonant frequency of the ultrasonic blade at room temperature.

24. The method according to claim 22, further comprising storing reference resonant frequency in the memory during manufacturing.

25. The method according to claim 22, further comprising storing the reference resonant frequency in the memory upon connection of the ultrasonic waveguide with the ultrasonic transducer.

26. The method according to claim 22, wherein determining the actual resonant frequency includes determining an impedance of the oscillating structure.

27. The method according to claim 22, wherein determining the actual resonant frequency includes determining a motional voltage of a drive signal used to drive the oscillating structure.

28. The method according to claim 22, further comprising:

comparing the determined temperature to a temperature threshold; and

outputting an alert where the determined temperature is above the temperature threshold.