Method for detecting presence of a blade in an ultrasonic system

• US 6,662,127 B2
• Filed: 05/29/2001
• Issued: 12/09/2003
• Est. Priority Date: 10/20/2000
• Status: Active Grant

• Current Assignee: Ethicon Endo-Surgery, Inc. (Johnson & Johnson)
• Original Assignee: Ethicon Endo-Surgery, Inc. (Johnson & Johnson)
• Inventors: Stulen, Foster B., Wiener, Eitan T., Friedman, Allan L.
• Primary Examiner(s): Hoff, Marc S.
• Assistant Examiner(s): West, Jeffrey R
• Application Number:
  US09/866,911
• Publication Number:
  US 20020049552A1
• Time in Patent Office: 924 Days
• Field of Search: 702/33, 702/39, 702/56, 702/65, 702/72, 702/75, 702/106, 702/108, 702/113, 702/115, 702/116, 702/117, 702/119, 702/182, 702/183, 702/188, 702/189, 73/18.2, 736/06, 736/07, 736/18, 600/437-472, 600/441, 600/564, 600/568, 604/22, 606/128, 606/169, 606/49, 606/167, 606/168
• US Class Current: 702/75
• CPC Class Codes: A61B 17/320068 using mechanical vibrations, e.g. ultrasonic A61B17/22012 takes precedence; dental tooth drilling devices operated by vibration A61C3/03; removing intra-ocular material using mechanical vibrations A61F9/00745
• CPC Class Codes: A61B 2017/00482 with a code
• CPC Class Codes: A61B 2017/00725 Calibration or performance testing
• CPC Class Codes: A61B 2017/320069 for ablating tissue
• CPC Class Codes: A61B 2017/320071 with articulating means for working tip
• CPC Class Codes: A61B 2017/320089 node location
• CPC Class Codes: A61B 2090/0809 Indication of cracks or breakages
• CPC Class Codes: A61B 2090/0812 indicating loosening or shifting of parts of an instrument, signaling maladjustment of parts

Abstract

The type of blade installed in a hand piece of an ultrasonic system is determined and the information used to adjust the fault detection threshold of the generator by using an impedance diagram to determine the type of blade which is connected to the hand piece. A check is performed to determine the magnitude of the blade impedance at resonance. If the hand piece is bare (i.e. no blade is attached), the magnitude of the impedance at resonance is typically less than 125 ohms. If on the other hand, a blade is connected, the impedance will be greater that 125 ohms. This value is used to indicated the presence or absence of a blade.

Claims

1. A method for detecting presence of a blade in an ultrasonic surgical system, comprising the steps of:

applying a drive signal to a hand piece without the blade attached using an ultrasonic generator;

performing multiple frequency sweeps across a predetermined frequency range;

storing a resonance frequency value, a minimum impedance value, and a phase margin value of the hand piece across the predetermined frequency range at the minimum impedance value of the hand piece;

determining whether the resonance frequency value, the phase margin value and the minimum impedance value of the hand piece are within acceptable limits;

if the resonance frequency value, the phase margin value and the minimum impedance value of the hand piece are within acceptable limits, connecting the blade to the hand piece and re-exciting the hand piece/blade with the drive signal across the predetermined frequency range;

storing the resonance frequency value and the phase margin value of the hand piece/blade across the predetermined frequency range at the minimum impedance value of the hand piece/blade; and

if the resonance frequency value and the minimum impedance value of the hand piece/blade are within acceptable limits, displaying a message on a liquid crystal display of the generator.

2. The method of claim 1, wherein the step of applying the drive signal comprises exciting the hand piece with an ultrasonic signal across a predetermined target frequency range without a blade attached to the hand piece.

3. The method of claim 2, wherein the predetermined target frequency range is from 50 kHz to 56 kHz.

4. The method of claim 1, wherein the multiple frequency sweeps across the predetermined frequency range are performed in a range from 50 kHz to 56 kHz.

5. The method of claim 4, wherein three frequency sweeps are performed.

6. The method of claim 1, wherein said determining step comprises:

determining whether the resonance frequency is greater than 50 kHz and less than 52 kHz, the phase margin is greater than 250 Hz, and the minimum impedance value is greater than 350 ohms.

7. The method of claim 6, further comprising the step of:

displaying the message on the liquid crystal display of the generator, if at least one of the resonance frequency, the phase margin and the minimum impedance of the hand piece is within the acceptable limits.

8. The method of claim 7, wherein the step of displaying the message comprises displaying a “

Bad Hand Piece”

message on the liquid crystal display.

9. The method of claim 6, further comprising the step of:

determining whether a test tip is connected to the hand piece.

10. The method of claim 9, wherein the step of determining whether a test tip is connected to the hand piece comprises:

determining whether the resonance frequency is greater than 54 KHz,

the phase margin is greater than 150 Hz and less than 250 Hz, and the minimum impedance is greater than 35 Ohms.

11. The method of claim 10, further comprising the step of:

displaying the message on the liquid crystal display of the generator, if the resonance frequency and minimum impedance and the phase margin of the hand piece are within the acceptable limits.

12. The method of claim 11, wherein the step of displaying the message comprises displaying a “

Broken Hand Piece with a Test Tip”

message on the liquid crystal display.

13. The method of claim 10, further comprising the step of:

determining whether the phase margin is less than 150 Hz and the resonance frequency is greater than 25 KHz.

14. The method of claim 10, further comprising the step of:

displaying the message on the liquid crystal display of the generator, if the phase margin is less than 150 Hz and the resonance frequency is greater than 25 KHz.

15. The method of claim 14, wherein the step of displaying the message comprises displaying a “

Broken/Loose Stud”

message on the liquid crystal display.

16. The method of claim 1, further comprising the steps of:

determining whether the resonance frequency is greater than 52 kHz and less than 54 kHz.

17. The method of claim 16, further comprising the step of:

displaying the message on the liquid crystal display of the generator, if the resonance frequency of the hand piece/blade is within the acceptable limits.

18. The method of claim 17, wherein the step of displaying the message comprises displaying a “

Broken Blade”

message on the liquid crystal display.

19. The method of claim 10, further comprising the steps of:

determining whether

the resonance frequency is greater than 54 kHz; and

the minimum impedance is less than 300 ohms.

20. The method of claim 19, further comprising the step of:

displaying the message on the liquid crystal display of the generator, if the hand piece/blade resonance frequency and the minimum impedance are greater than 54 kHz and less than 300 ohms, respectively.

21. The method of claim 20, wherein the step of displaying the message comprises displaying a “

Good Blade”

message on the liquid crystal display.

22. The method of claim 19, further comprising the step of:

displaying the message on the liquid crystal display of the generator, if the hand piece/blade resonance frequency and the minimum impedance is less than 54 kHz and less than 300 ohms, respectively;

removing the blade; and

returning to the step of determining whether the test tip is connected to the hand piece.

23. The method of claim 22, wherein the step of displaying the message comprises displaying a “

Repeat Test With No Blade”

message on the liquid crystal display.