Devices and techniques for cutting and coagulating tissue

• US 8,546,996 B2
• Filed: 08/14/2012
• Issued: 10/01/2013
• Est. Priority Date: 08/06/2008
• Status: Active Grant

• Current Assignee: Cilag Gmbh International (Johnson & Johnson)
• Original Assignee: Ethicon Endo-Surgery, Inc. (Johnson & Johnson)
• Inventors: Messerly, Jeffrey D., Wiener, Eitan T., Noyes, Brian T., Aldridge, Jeffrey L., Giordano, James R., Beetel, Robert J., Abbott, Daniel J., Stulen, Foster B., Miller, Matthew C., Price, Nathan J., Price, Daniel W.
• Primary Examiner(s): DOUGHERTY, THOMAS M
• Application Number:
  US13/585,124
• Publication Number:
  US 20120310263A1
• Time in Patent Office: 413 Days
• Field of Search: 310/316.01, 310/316.02, 310/317, 606169-171
• US Class Current: 310/317
• 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 18/1206 Generators therefor
• CPC Class Codes: A61B 18/14 Probes or electrodes therefor
• CPC Class Codes: A61B 18/1445 at the distal end of a shaft, e.g. forceps or scissors at the end of a rigid rod
• CPC Class Codes: A61B 2017/00026 Conductivity or impedance, e.g. of tissue
• CPC Class Codes: A61B 2017/00084 Temperature
• CPC Class Codes: A61B 2017/00176 Two pulses, e.g. second pulse having an effect different from the first one
• CPC Class Codes: A61B 2017/00203 with speech control or speech recognition
• CPC Class Codes: A61B 2017/00973 pedal-operated
• CPC Class Codes: A61B 2017/320093 additional movable means performing cutting operation
• 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: A61B 2018/00005 Cooling or heating of the probe or tissue immediately surrounding the probe
• CPC Class Codes: A61B 2018/00303 active, e.g. with a motor creating vibrations
• CPC Class Codes: A61B 2018/00589 Coagulation
• CPC Class Codes: A61B 2018/00601 Cutting
• CPC Class Codes: A61B 2018/0063 Sealing
• CPC Class Codes: A61B 2018/00666 using a threshold value
• CPC Class Codes: A61B 2018/00791 Temperature
• CPC Class Codes: A61B 2018/00845 Frequency
• CPC Class Codes: A61B 2018/00875 : Resistance or impedance
• CPC Class Codes: A61B 2018/00994 : combining two or more different kinds of non-mechanical energy or combining one or more non-mechanical energies with ultrasound
• CPC Class Codes: A61B 5/053 : Measuring electrical impedance or conductance of a portion of the body
• CPC Class Codes: A61B 5/4836 : Diagnosis combined with treatment in closed-loop systems or methods A61B5/0036 takes precedence
• CPC Class Codes: A61N 7/00 : Ultrasound therapy lithotripsy A61B17/22, A61B17/225; massage using supersonic vibration A61H23/00 ; using ultrasound for introducing media into the body A61M37/0092
• CPC Class Codes: A61N 7/02 : Localised ultrasound hyperthermia hyperthermia in general A61F7/00
• CPC Class Codes: B06B 1/0284 : with consecutive, i.e. sequential generation, e.g. with frequency sweep
• CPC Class Codes: B06B 2201/76 : Medical, dental
• CPC Class Codes: G05B 15/02 : electric

Abstract

Various embodiments are directed to an apparatus and method of driving an end effector coupled to an ultrasonic drive system of a surgical instrument. The method comprises generating at least one electrical signal. The at least one electrical signal is monitored against a first set of logic conditions.

Claims

1. A method of driving an ultrasonic transducer of a surgical instrument, the method comprising:

generating by a generator coupled to an ultrasonic transducer at least one time varying electrical signal at a resonant frequency of the ultrasonic transducer;

sampling the frequency of the at least one time varying electrical signal over a predetermined time period to obtain at least two sampled frequency data points of the at least one time varying signal;

calculating a frequency slope between the at least two sampled frequency data points of the at least one time varying electrical signal over the predetermined time period, where the frequency slope is the difference between the at least two sampled frequency data points over the predetermined time period;

comparing the frequency slope to a frequency slope threshold; and

triggering a first response of the generator when the frequency slope crosses the frequency slope threshold.

2. The method of claim 1, comprising:

comparing the frequency slope to the frequency slope threshold; and

triggering a second response of the generator when the frequency slope crosses the frequency slope threshold.

3. The method of claim 2, comprising:

determining when the frequency slope is less than the frequency slope threshold;

incrementing a timer when the frequency slope is less than the frequency slope threshold;

determining when the timer is greater than a required trigger time;

setting a logic condition when the timer is greater than the required trigger time.

4. The method of claim 3, comprising:

incrementing the timer when the resonant frequency is less than frequency threshold and the frequency slope is less than the frequency slope threshold.

5. The method of claim 2, comprising:

comparing the frequency slope to a cross-back frequency slope threshold, wherein the cross-back frequency slope threshold is the frequency slope threshold above which a triggered response stops.

6. The method of claim 1, comprising:

providing the sampled frequency data points to a moving average filter; and

calculating by the moving average filter an exponentially weighted moving average of the sampled frequency.

7. The method of claim 6, comprising:

calculating the exponentially weighted moving average of the sampled frequency according to the following formula;

S′

_tf=α

′

Y′

_tf+(1−

α

′

)S′

_tf-1

where;

S′

_tf is the current moving average of the frequency slope of the sampled frequency;

S′

_tf-1 is the previous moving average of the frequency slope of the sampled frequency;

α

′

is the smoothing factor; and

Y′

_tf is the current slope data point of the sampled frequency.

8. The method of claim 1, comprising sampling a voltage of the at least one time varying electrical signal.

9. The method of claim 8, comprising:

providing the sampled voltage to a moving average filter; and

calculating by the moving average filter an exponentially weighted moving average of the sampled voltage.

10. The method of claim 9, comprising:

calculating the exponentially weighted moving average of the sampled voltage according to the following formula;

S′

_tv=α

′

Y′

_tv+(1−

α

′

)S′

_tv-1

where;

S′

_tv is the current moving average of the sampled voltage;

S′

_tv-1 is the previous moving average of the sampled voltage;

α

′

is the smoothing factor; and

Y′

_tv is current data point of the sampled voltage.

11. An ultrasonic drive system for driving an ultrasonic transducer of a surgical instrument, the ultrasonic drive system comprising:

a generator coupled to the ultrasonic transducer to generate at least one time varying electrical signal at a resonant frequency of the ultrasonic transducer;

an analog-to-digital converter coupled to the generator to sample the frequency of the at least one time varying electrical signal over a predetermined time period to obtain at least two sampled frequency data points of the at least one time varying signal; and

a processor coupled to the analog-to-digital converter, wherein the processor is operative to;

calculate a frequency slope between the at least two sampled frequency data points of the at least one time varying electrical signal over a predetermined time period, where the frequency slope is the difference between the at least two sampled frequency data points over the predetermined time period;

compare the frequency slope to a frequency slope threshold; and

trigger a first response of the generator when the frequency slope crosses the frequency slope threshold.

12. The ultrasonic drive system of claim 11, wherein the processor is operative to:

compare the frequency slope to the frequency slope threshold; and

trigger a second response of the generator when the frequency slope crosses the frequency slope threshold.

13. The ultrasonic drive system of claim 12, wherein the processor is operative to:

determine when the frequency slope is less than the frequency slope threshold;

increment a timer when the frequency slope is less than the frequency slope threshold;

determine when the timer is greater than a required trigger time;

set a logic condition when the timer is greater than the required trigger time.

14. The ultrasonic drive system of claim 12, wherein the processor is operative to:

increment the timer when the resonant frequency is less than the frequency threshold and the frequency slope is less than the frequency slope threshold.

15. The ultrasonic drive system of claim 12, wherein the processor is operative to:

compare the frequency slope to a cross-back frequency slope threshold, wherein the cross-back frequency slope threshold is the frequency slope threshold above which a triggered response stops.

16. The ultrasonic drive system of claim 11, comprising:

a moving average filter coupled to the processor, the moving average filter to receive the sampled frequency data points; and

calculate an exponentially weighted moving average of the sampled frequency.

17. The ultrasonic drive system of claim 16, wherein the moving average filter is operative to calculate the exponentially weighted moving average of the sampled frequency according to the following formula:

S′

_tf=α

′

Y′

_tf+(1−

α

′

)S′

_tf-1

where;

S′

_tf is the current moving average of the frequency slope of the sampled frequency;

S′

_tf-1 is the previous moving average of the frequency slope of the sampled frequency;

α

′

is the smoothing factor; and

Y′

_tf is the current slope data point of the sampled frequency.

18. The ultrasonic drive system of claim 11, wherein the analog-to-digital converter is operative to sample a voltage of the at least one time varying electrical signal.

19. The ultrasonic drive system of claim 18, comprising:

a moving average filter coupled to the processor, the moving average filter to receive the sampled voltage data points; and

calculate an exponentially weighted moving average of the sampled voltage.

20. The ultrasonic drive system of 19, wherein the moving average filter is operative to calculate the exponentially weighted moving average of the sampled voltage according to the following formula:

S′

_tv=α

′

Y′

_tv+(1−

α

′

)S′

_tv-1

where;

S′

_tv is the current moving average of the sampled voltage;

S′

_tv-1 is the previous moving average of the sampled voltage;

α

′

is the smoothing factor; and

Y′

_tv is current data point of the sampled voltage.

21. A surgical instrument, comprising:

an ultrasonic transducer;

an end effector coupled to the ultrasonic transducer; and

an ultrasonic drive system coupled to the ultrasonic transducer, the ultrasonic drive system comprising;

a generator coupled to the end effector to generate at least one time varying electrical signal at a resonant frequency of the ultrasonic transducer;

an analog-to-digital converter coupled to the generator to sample the frequency of the at least one time varying electrical signal over a predetermined time period to obtain at least two sampled frequency data points of the at least one time varying signal; and

a processor coupled to the analog-to-digital converter, wherein the processor is operative to;

calculate a frequency slope between the at least two sampled frequency data points of the at least one time varying electrical signal over a predetermined time period, where the frequency slope is the difference between the at least two sampled frequency data points over the predetermined time period;

compare the frequency slope to a frequency slope threshold; and

trigger a first response of the generator when the frequency slope crosses the frequency slope threshold.