Method of maintaining constant movement of a cutting blade of an ultrasonic waveguide

• US 8,333,779 B2
• Filed: 03/25/2011
• Issued: 12/18/2012
• Est. Priority Date: 12/03/2007
• Status: Active Grant

• Current Assignee: Covidien AG (Medtronic Plc)
• Original Assignee: Covidien AG (Medtronic Plc)
• Inventors: Smith, Kevin W., Bales, Thomas O. Jr., Palmer, Matthew A., Deville, Derek Dee
• Primary Examiner(s): Severson, Ryan
• Assistant Examiner(s): SHI, KATHERINE MENGLIN
• Application Number:
  US13/072,273
• Publication Number:
  US 20110190800A1
• Time in Patent Office: 634 Days
• Field of Search: 606/45, 606/169, 310/316.01, 310/316.02, 310/317, 839/56, 601/2
• US Class Current: 606/169
• CPC Class Codes: A61B 17/1285 for minimally invasive surgery
• CPC Class Codes: A61B 17/32 Surgical cutting instruments A61B18/042 takes precedence; suture cutters A61B17/0467; instruments for ligaturing or cutting A61B17/128; instruments for rupturing the amniotic membrane A61B17/4208; specially adapted knives for eye surgery A61F9/0133
• 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 17/320092 with additional movable means for clamping or cutting tissue, e.g. with a pivoting jaw
• CPC Class Codes: A61B 2017/00017 Electrical control of surgical instruments
• CPC Class Codes: A61B 2017/00075 Motion
• CPC Class Codes: A61B 2017/00137 Details of operation mode
• CPC Class Codes: A61B 2017/0046 with a releasable handle; with handle and operating part separable for prosthetic joint-implanting tools A61F2/4603
• CPC Class Codes: A61B 2017/00477 Coupling A61B2017/0046 takes precedence
• CPC Class Codes: A61B 2017/00734 battery operated
• CPC Class Codes: A61B 2017/320089 node location
• 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 2017/320097 with stapling means
• CPC Class Codes: A61B 2017/320098 with transverse or torsional motion
• CPC Class Codes: A61B 2090/0803 Counting the number of times an instrument is used
• CPC Class Codes: A61B 2090/0807 Indication means
• CPC Class Codes: B06B 3/00 Methods or apparatus specially adapted for transmitting mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
• CPC Class Codes: Y10T 29/49005 Acoustic transducer
• CPC Class Codes: Y10T 29/49169 : Assembling electrical component directly to terminal or elongated conductor

Abstract

A method of maintaining constant movement of a cutting blade of an ultrasonic waveguide includes the steps of providing an ultrasonic transducer operable to convert a received motional voltage into a movement of a cutting blade of an ultrasonic waveguide, a motional feedback circuit connected in a parallel configuration with the ultrasonic transducer, and a variable power source operable to apply a first voltage between a set of connection points to the parallel configuration. A feedback voltage measured from the motional feedback circuit is determined and an output of the power source is varied based upon the measured feedback voltage to result in a substantially constant feedback voltage and, thereby, maintain a substantially constant rate of movement of the cutting blade across a variety of cutting loads.

Claims

1. A method of maintaining constant movement of a cutting blade of an ultrasonic waveguide, which comprises:

providing;

an ultrasonic transducer operable to convert a received motional voltage into a movement of a cutting blade of an ultrasonic waveguide;

a first capacitive element in a series configuration with the ultrasonic transducer;

a motional feedback circuit connected in a parallel configuration with the ultrasonic transducer and comprising a second capacitive element and a third capacitive element in a series configuration with each other and, together, connected in a parallel configuration with the series configuration of the ultrasonic transducer and the first capacitive element, a capacitive value of the third capacitive element selected to be a fraction of a capacitive value of the ultrasonic transducer, the fraction having a value less than one, a capacitive value of the second capacitive element having a capacitive value of the first capacitive element multiplied by the fraction; and

a variable power source operable to apply a first voltage between a set of connection points to the parallel configuration;

determining a feedback voltage measured from the motional feedback circuit; and

varying an output of the power source based upon the measured feedback voltage to result in a substantially constant feedback voltage and, thereby, maintain a substantially constant rate of movement of the cutting blade across a variety of cutting loads.

2. The method according to claim 1, wherein the variable power source is connected in a parallel configuration with the series configuration of the transducer and the first capacitive element and with the series configuration of the second and third capacitive elements.

3. The method according to claim 1, which further comprises carrying out the determining step by measuring the feedback voltage from a first point located between the second and third capacitive elements and a second point located between the transducer and the first capacitive element.

4. The method according to claim 1, wherein the second and third capacitive elements have a combined capacitive value that is less than the first capacitive element.

5. The method according to claim 1, wherein a value of the motional voltage is a product of the fraction multiplied by the measured feedback voltage.

6. The method according to claim 1, which further comprises providing a voltage controller for carrying out the step of varying an output of the power source.

7. The method according to claim 6, wherein:

the voltage controller comprises a processor;

the variable power source comprises a phase locked loop communicatively coupled to the processor, and which further comprises;

determining a frequency of movement of the cutting blade with the phase locked loop; and

utilizing the phase of the motional voltage to control the movement of the cutting blade such that the movement remains resonant along the ultrasonic waveguide.

8. The method according to claim 1, which further comprises:

providing a clamping mechanism having a range of clamping force values and being operable to place material in physical contact with the cutting blade;

communicatively coupling the voltage controller to the clamping mechanism; and

varying the motional voltage with the voltage controller based upon a given clamping value within the range of clamping values.

9. The method according to claim 1, wherein the variable power source comprises a removable battery.

10. The method according to claim 1, which further comprises providing a disposable handle body with:

a portion defining a battery-holding compartment having at least two battery contacts;

a waveguide attachment dock exposed to the environment and shaped to accept the ultrasonic waveguide therein;

a transducer attachment dock exposed to the environment and shaped to place the ultrasonic transducer in coaxial alignment with the ultrasonic waveguide when the ultrasonic waveguide is disposed within the waveguide attachment dock; and

an ultrasonic-signal-generator assembly dock exposed to the environment and shaped to substantially simultaneously;

selectively removably secure at least the ultrasonic transducer to the handle body;

place an end of the ultrasonic transducer within the transducer attachment dock; and

electrically couple at least the ultrasonic transducer to the at least two battery contacts.

11. A method of maintaining constant movement of a cutting blade of an ultrasonic waveguide, which comprises:

providing;

an ultrasonic transducer operable to convert a received motional voltage into a movement of a cutting blade of an ultrasonic waveguide;

a first capacitive element in a series configuration with the ultrasonic transducer;

a second capacitive element and a third capacitive element in a series configuration with each other and, together, connected in a parallel configuration with the series configuration of the ultrasonic transducer and the first capacitive element, a capacitive value of the third capacitive element selected to be a fraction of a capacitive value of the ultrasonic transducer, the fraction having a value less than one, a capacitive value of the second capacitive element having a capacitive value of the first capacitive element multiplied by the fraction; and

a variable power source connected in a parallel configuration with;

the series configuration of the ultrasonic transducer and the first capacitive element; and

the series configuration of the second and third capacitive elements, the variable power source operable to apply a first voltage between a set of connection points to the parallel configuration;

determining a feedback voltage measured from a first point located between the second and third capacitive elements and a second point located between the ultrasonic transducer and the first capacitive element; and

varying an output of the power source based upon the measured feedback voltage to result in a substantially constant feedback voltage and, thereby, maintain a substantially constant rate of movement of the cutting blade across a variety of cutting loads.

12. The method according to claim 11, wherein the second and third capacitive elements have a combined capacitive value that is less than the first capacitive element.

13. The method according to claim 11, wherein a value of the motional voltage is a product of the fraction multiplied by the measured feedback voltage.

14. The method according to claim 11, which further comprises providing a voltage controller for carrying out the step of varying an output of the power source.

15. The method according to claim 14, wherein:

the voltage controller comprises a processor;

the variable power source comprises a phase locked loop communicatively coupled to the processor, and which further comprises;

determining a frequency of movement of the cutting blade with the phase locked loop; and

utilizing the phase of the motional voltage to control the movement of the cutting blade such that the movement remains resonant along the ultrasonic waveguide.

16. The method according to claim 11, which further comprises:

providing a clamping mechanism having a range of clamping force values and being operable to place material in physical contact with the cutting blade;

communicatively coupling the voltage controller to the clamping mechanism; and

varying the motional voltage with the voltage controller based upon a given clamping value within the range of clamping values.

17. A method of maintaining constant movement of a cutting blade of an ultrasonic waveguide, which comprises:

providing;

an ultrasonic transducer operable to convert a received motional voltage into a movement of a cutting blade of an ultrasonic waveguide;

a removable battery;

a disposable handle body with;

a portion defining a battery-holding compartment having at least two battery contacts;

a waveguide attachment dock exposed to the environment and shaped to accept the ultrasonic waveguide therein;

a transducer attachment dock exposed to the environment and shaped to place the ultrasonic transducer in coaxial alignment with the ultrasonic waveguide when the ultrasonic waveguide is disposed within the waveguide attachment dock; and

an ultrasonic-signal-generator assembly dock exposed to the environment and shaped to substantially simultaneously;

selectively removably secure at least the ultrasonic transducer to the handle body;

place an end of the ultrasonic transducer within the transducer attachment dock; and

electrically couple at least the ultrasonic transducer to the at least two battery contacts;

a first capacitive element in a series configuration with the ultrasonic transducer;

a second capacitive element and a third capacitive element in a series configuration with each other and, together, connected in a parallel configuration with the series configuration of the ultrasonic transducer and the first capacitive element, a capacitive value of the third capacitive element selected to be a fraction of a capacitive value of the ultrasonic transducer, the fraction having a value less than one, a capacitive value of the second capacitive element having a capacitive value of the first capacitive element multiplied by the fraction; and

a variable power source connected in a parallel configuration with;

the series configuration of the ultrasonic transducer and the first capacitive element; and

the series configuration of the second and third capacitive elements, the variable power source operable to apply a first voltage between a set of connection points to the parallel configuration;

determining a feedback voltage measured from a first point located between the second and third capacitive elements and a second point located between the ultrasonic transducer and the first capacitive element; and

varying an output of the power source based upon the measured feedback voltage to result in a substantially constant feedback voltage and, thereby, maintain a substantially constant rate of movement of the cutting blade across a variety of cutting loads.

18. The method according to claim 17, wherein the second and third capacitive elements have a combined capacitive value that is less than the first capacitive element.

19. The method according to claim 17, wherein a value of the motional voltage is a product of the fraction multiplied by the measured feedback voltage.

20. The method according to claim 17, which further comprises providing a voltage controller for carrying out the step of varying an output of the power source.

21. The method according to claim 20, wherein:

the voltage controller comprises a processor;

the variable power source comprises a phase locked loop communicatively coupled to the processor, and which further comprises;

determining a frequency of movement of the cutting blade with the phase locked loop; and

utilizing the phase of the motional voltage to control the movement of the cutting blade such that the movement remains resonant along the ultrasonic waveguide.

22. The method according to claim 17, which further comprises:

providing a clamping mechanism having a range of clamping force values and being operable to place material in physical contact with the cutting blade;

communicatively coupling the voltage controller to the clamping mechanism; and

varying the motional voltage with the voltage controller based upon a given clamping value within the range of clamping values.