Electrosurgical unit

• US 3,885,569 A
• Filed: 11/21/1972
• Issued: 05/27/1975
• Est. Priority Date: 11/21/1972
• Status: Expired due to Term

• Current Assignee: Donald W. Judson
• Original Assignee: Donald W. Judson
• Inventors: Judson, Donald W.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US05/308,488
• Time in Patent Office: 917 Days
• Field of Search: 128/303.13,303.14,303.17,303.18,421,422,423,2.1P
• US Class Current: 606/37
• CPC Class Codes: A61B 18/12 by passing a current through the tissue to be heated, e.g. high-frequency current
• CPC Class Codes: A61B 18/1206 Generators therefor
• CPC Class Codes: A61B 2018/0066 without feedback, i.e. open loop control
• CPC Class Codes: H02H 3/33 using summation current transformers H02H3/347 takes precedence

Abstract

An electrosurgical unit for generating electrical signals intended for application to the body of a patient via an electrosurgical electrode, is disclosed. Cutting signals and coagulation signals, as well as a blend of both signals, are generated by the unit under the control of a mode control circuit that is responsive to the operation of selector switches and/or manually operated actuators. Selected patient and unit conditions are monitored to have the electrosurgical unit disabled under certain dangerous conditions.

Claims

1. An electrosurgical unit for generating electrical signals to be applied to the body of a patient by an electrosurgical electrode for producing surgical cutting and coagulation as selected, said electrosurgical unit comprising:

a pair of output terminals adapted to be coupled to the electrosurgical electrode;

first means for providing a continuous alternating current cutting signal having a selected freuency that produces surgical cutting when applied to the body of a patient;

second means for cyclically disabling said first means to provide a coagulating signal that is a succession of bursts of said alternating current signal, said coagulating signal providing coagulation when applied to the body of a patient;

third means for altering the disabling cycle of said second means to extend the length of time said first means operates and to provide a blended signal that alternately produces cutting and coagulation when applied to the body of a patient; and

output means for applying the blended signal to the output terminals.

2. The electrosurgical unit defined by claim 1, said first means including:

drive means for providing drive pulses at a pulse rate corresponding to the frequency of said alternating current signal; and

wherein the output means is responsive to said drive pulses for providing said alternating current signal at the output terminals.

3. The electrosurgical unit defined by claim 2, said drive means including:

a first multivibrator for providing pulses at a rate that is twice said selected frequency;

a bistable means having two states and producing output signals corresponding to each of two states thereof, said bistable device being switched between said two states in response to said pulses from said first multivibrator; and

gating means connected to be responsive to said first multivibrator pulses and to the output signals of said bistable device for providing said drive pulses.

4. The electrosurgical unit defined by claim 3, said gating means including:

first and second NAND gates each receiving from said bistable device an output signal corresponding to a different one of said two states; and

a third NAND gate connected to be responsive to said first multivibrator for simultaneously providing to said first and second NAND gates an input signal corresponding to an inversion of said pulses from said first multivibrator.

5. The electrosurgical unit defined by claim 3, said second means including a second multivibrator connected to distable said bistable device for predetermined time periods at predetermined time intervals, said bistable device being prevented from providing said drive pulses to said gating means when disabled.

6. The electrosurgical unit defined by claim 5, said third means including means for alternately permitting and preventing, in accordance with a predetermined timing sequence, said second multivibrator from disabling said bistable device for said predetermined time periods at said predetermined time intervals.

7. The electrosurgical unit defined by claim 2, further including inductive coupling means for providing said drive pulses to said output means.

8. The electrosurgical unit defined by claim 2, said output means including:

a transistorized push-pull amplifier responsive to said drive pulses; and

a coupling transformer for inductively coupling the output of said push-pull amplifier to said output terminals.

9. The electrosurgical unit defined by claim 8 further including mode selection means for providing moDe selection signals to control the operation of said first, second, and third means to provide cutting signals, coagulation signals, or blended signals.

10. The electrosurgical unit defined by claim 9, further including manually operable actuator means for controlling the selection and generation of desired signals by said unit.

11. The electrosurgical unit defined by claim 8, wherein the push-pull amplifier includes a pair of inputs and an output and wherein the output means includes feedback means coupled between the output and inputs of the amplifier for altering the voltage level at the inputs of said amplifier in accordance with the voltage level at the output thereof to prevent said amplifier from attaining a saturated mode.

12. The electrosurgical unit defined by claim 8, wherein the output means includes a cut level control means and a coagulation level control means for individually controlling the gain of the push-pull amplifier to thereby control the amplitude of the output signal, said cut level control means and said coagulation control means being respectively operated in response to the application thereto of mode selection signals corresponding to cutting and coagulating signals, respectively.

13. The electrosurgical unit defined by claim 12, further including monitoring means for disabling said electrosurgical unit in response to the detection of unequal amounts of current flowing to and from a patient with respect to said unit.

14. The electrosurgical unit defined by claim 12, further including means for monitoring the temperature of said electrosurgical unit to disable said unit in response to said temperature thereof exceeding a selected temperature.

15. The electrosurgical unit defined by claim 14, said drive means including:

a first multivibrator for providing pulses at a rate that is twice said selected frequency;

a bistable means having two states and producing output signals corresponding to each of two states thereof said bistable device being switched between said two states in response to said pulses from said first multivibrator; and

gating means connected to be responsive to said first multivibrator pulses and to the output signals of said bistable device for providing said drive pulses.

16. The electrosurgical unit defined by claim 15, said second means including a second multivibrator connected to disable said bistable device for predetermined time periods at predetermined time intervals, said bistable device being prevented from providing said drive pulses to said gating means when disabled.

17. The electrosurgical unit defined by claim 16, said third means including means for alternately permitting and preventing, in accordance with a predetermined timing sequence, said second multivibrator from disabling said bistable device for said predetermined time periods at said predetermined time intervals.

18. The electrosurgical unit defined by claim 17, further including inductive coupling means for providing said drive pulses to said output means.

19. The electrosurgical unit defined by claim 1 further including actuator means for controlling the selection and generation of said cutting signals, coagulating signals, and blended signals in response to manual manipulation of said actuator means.

20. The electrosurgical unit defined by claim 19, further including mode selection means for generating mode selection signals in response to operation of said actuator means, said mode selection signals being applied to control the operation of said first, second and third means to have selectively provided said cutting signals, coagulating signals, and said blended signals.

21. The electrosurgical unit defined by claim 1, further including monitoring means for disabling said electrosurgical unit in response to the detection of unequal amounts of current flowing to and from a patient with respect to said unit.

22. The electrosurgical unit defined by claim 1, further includiNg means for controlling the output amplitude of said cutting signals and said coagulating signals.

23. The electrosurgical unit defined by claim 1 wherein the output means includes level control means for providing the independent adjustment of the amplitude level of the cutting and coagulating components of the blended signal.

24. The electrosurgical unit defined by claim 23 wherein the level control means includes means for manually adjusting said level control means.

25. The electrosurgical unit defined by claim 24 wherein said third means includes means to provide a blended signal in which the cutting component has a time duration of approximately three times the time duration of the coagulating component.

26. An electrosurgical unit for generating electrical signals to be applied to the body of a patient by an electrosurgical electrode for producing surgical cutting and coagulation, the electrosurgical unit comprising:

first means for generating a high frequency cutting signal for producing surgical cutting when applied to the body of a patient;

second means for generating a succession of bursts of a high frequency signal for providing a coagulating signal which produces coagulation when applied to the body of a patient;

a pair of output terminals adapted to be coupled to the electrosurgical electrode;

output means coupled between the first and second means and the output terminals for applying a blended signal to the output terminals, the blended signal consisting of successive intervals of the cutting signal and coagulating signal to alternately produce cutting and coagulation when applied to the body of a patient; and

level control means coupled to the output means for providing an independent adjustment of the amplitude level of the cutting and coagulating components of the blended signal.