Method and system for controlling output of RF medical generator

• US 7,901,400 B2
• Filed: 01/27/2005
• Issued: 03/08/2011
• Est. Priority Date: 10/23/1998
• Status: Expired due to Fees

• Current Assignee: Covidien AG (Medtronic Plc)
• Original Assignee: Covidien AG (Medtronic Plc)
• Inventors: Shields, Chelsea, James, Jeremy S., Wham, Robert H., Tetzlaff, Philip M.
• Primary Examiner(s): PEFFLEY, MICHAEL F
• Application Number:
  US11/044,805
• Publication Number:
  US 20050203504A1
• Time in Patent Office: 2,231 Days
• Field of Search: 606 32- 34, 606 40- 42
• US Class Current: 606/34
• CPC Class Codes: A61B 18/1206 Generators therefor
• CPC Class Codes: A61B 18/1442 Probes having pivoting end effectors, e.g. forceps
• CPC Class Codes: A61B 2018/0016 Energy applicators arranged in a two- or three dimensional array
• CPC Class Codes: A61B 2018/0063 Sealing
• CPC Class Codes: A61B 2018/00684 using lookup tables
• 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 2090/061 for measuring dimensions, e.g. length

Abstract

A system and method are provided for controlling an electrosurgical generator generating electrosurgical energy which is delivered to a patient for performing an electrosurgical procedure for sealing tissue. The system includes a control module executable on a processor for receiving sensed data corresponding to at least one physical or electrical property related to delivery of the electrosurgical energy. The control module processes the received sensed data and controls the electrosurgical generator including generating at least one corresponding control signal in accordance with the processed sensed data for regulating electrosurgical energy output from the electrosurgical generator. The controlling the electrosurgical generator further includes regulating at least one control variable, a respective control variable of the at least one control variable corresponding to sensed data corresponding to a property of the at least one physical or electrical property to follow at least one mapping for optimizing the tissue sealing.

Claims

1. An electrosurgical generator configured to generate electrosurgical energy delivered to a patient for performing an electrosurgical procedure for sealing tissue, the generator comprising:

at least one sensor configured to sense at least one of a physical and electrical property related to the delivery of the electrosurgical energy;

at least one processor configured to receive sensed data corresponding to the at least one of the physical and electrical property and to process at least a portion of said received sensed data to control the electrosurgical generator, the at least one processor further configured to continuously compare the received sensed data to a mapping having a time-based plot of desired progression of the at least one of the physical and electrical property, the at least one processor configured to generate at least one control signal as a function of the comparison of the sensed data with the mapping for regulating electrosurgical energy output from said electrosurgical generator; and

the at least one processor including a first control module for controlling an inner control loop for controlling the electrosurgical generator in accordance with a first mapping of the mapping and a second control module for controlling an outer control loop for controlling the second control module in accordance with a second mapping of the mapping.

2. The electrosurgical generator according to claim 1, wherein the at least one processor determines a differential between the sensed data and a corresponding point of the time-based plot of desired progression of the at least one of the physical and electrical property and a target value and wherein the at least one processor controls the electrosurgical generator in accordance with the determined differential.

3. The electrosurgical generator according to claim 1, wherein the mapping is selected from the group of mappings consisting of a look-up table, a function and a continuous value mapping.

4. The electrosurgical generator according to claim 1, wherein the at least one of the physical and electrical property is selected from the group of properties consisting of temperature, impedance, current, power and voltage of the tissue proximate the surgical site.

5. The electrosurgical generator according to claim 1, wherein the at least one processor is further configured to receive and process additional data and generate the at least one control signal in accordance with the received and processed additional data, wherein the additional data is selected from at least one of an actual optical characteristic of tissue proximate the surgical site selected from the group of characteristics consisting of absorption properties, reflectivity properties, transmissivity properties and opaqueness properties, actual volume of tissue between jaws of an electrosurgical instrument delivering the electrosurgical energy, an actual elastomeric property of tissue proximate the surgical site, actual viability of tissue proximate the surgical site, actual pressure reactivity of tissue proximate the surgical site, actual moisture content level of tissue proximate the surgical site;

actual thickness of tissue proximate the surgical site, actual gap between electrodes of the electrosurgical instrument, actual pressure applied by the electrosurgical instrument, actual leakage current, a desired optical characteristic of tissue proximate the surgical site selected from the group of characteristics consisting of absorption properties, reflectivity properties, transmissivity properties and opaqueness properties, desired volume of tissue between jaws of the electrosurgical instrument, a desired elastomeric property of tissue proximate the surgical site, desired viability of tissue proximate the surgical site, desired viability of sealed tissue, desired pressure reactivity of tissue proximate the surgical site, desired moisture content level of tissue proximate the surgical site;

desired thickness of tissue proximate the surgical site, desired gap between electrodes of the electrosurgical instrument, desired pressure applied by the electrosurgical instrument type of electrosurgical instrument, type of tissue being sealed, patient profile data, patient'"'"'s disease profile data, at least one mapping of the at least one mapping, allowed leakage current, applied voltage, applied current, at least one predetermined threshold value and at least one target parameter for a corresponding parameter of the electrosurgical energy.

6. The electrosurgical generator according to claim 5, wherein the at least one processor is further configured to determine a change in values of the data over a variable, a rate of change of the data over the variable, and a change of rate of change of the data over the variable, and to determine when an event has occurred, the event being selected from the group of events consisting of exceeding a predetermined threshold value by the data, by the change in values of the data over the variable, by the rate of change of the data over the variable, by the change of the rate of change of the data over the variable, by a difference between the data and a predetermined value, by a determined seal quality value, by a determined seal completion value, by a difference between the sensed data and a corresponding target value obtained from the at least one mapping, and by a timing value generated by a timing device.

7. The electrosurgical generator according to claim 6, wherein the at least one processor is further configured to determine when the quality of a seal is below a predetermined threshold level, and upon determining that the seal quality is below the predetermined threshold level the at least one processor initiates a new electrosurgical procedure for sealing tissue.

8. The electrosurgical generator according to claim 7, wherein the initiating the new electrosurgical procedure includes using at least one of the sensed data and parameter settings of the electrosurgical energy from the previous procedure for controlling the electrosurgical generator for the new procedure.

9. The electrosurgical generator according to claim 6, further comprising an indicator device configured to indicate to an operator at least one of the determined seal quality, and a representation of a comparison of the sensed data with the mapping.

10. The electrosurgical generator according to claim 5, wherein the at least one processor is further configured to determine imminent damage to tissue proximate the surgical site, actual damage to tissue proximate the surgical site, imminent thermal spread to tissue proximate the surgical site, and actual thermal spread to tissue proximate the surgical site.

11. The electrosurgical generator according to claim 10, wherein upon determining at least one of the imminent damage, the actual damage, the imminent thermal spread, and the actual thermal spread, the at least one processor performs at least one of controlling the electrosurgical generator for regulating the output of the electrosurgical generator by at least one of reducing output electrosurgical energy and discontinuing output of electrosurgical energy and generating at least one additional control signal for controlling an indicator device for notifying an operator.

12. The electrosurgical generator according to claim 5, wherein the additional data is at least one of sensed and user entered.

13. The electrosurgical generator according to claim 5, wherein the additional data is at least one of received and processed at a pre-surgical time before beginning the electrosurgical procedure and a concurrent-surgical time during the electrosurgical procedure.

14. The electrosurgical generator according to claim 5, wherein the at least one processor is further configured to determine the tissue type.

15. The electrosurgical generator according to claim 5, wherein at least one of the received sensed data and additional data is received at a pre-surgical time before beginning the procedure, and the at least one of the received sensed data and additional data responds to application of a pre-surgical electrosurgical energy applied before beginning the electrosurgical procedure.

16. The electrosurgical generator according to claim 5, wherein the at least one processor is further configured to control the electrosurgical energy by initializing parameters of the electrosurgical energy before beginning the electrosurgical procedure.

17. The electrosurgical generator according to claim 1, wherein mapping includes a continuous value mapping having a target curve plotted over a variable, wherein at a respective point on the target curve the target curve has a target slope and during the procedure a rate of change of the sensed data is compared to the target slope for a respective point on the target curve that corresponds to a condition of the variable when the data was sensed, and the controlling of the electrosurgical generator is in accordance with the results of the comparison.

18. The electrosurgical generator according to claim 17, wherein the target curve includes at least a first stage having a first target slope and second stage having a second target slope, and the first and second target slopes are different, and the controlling of the electrosurgical generator includes changing control from controlling in accordance with the first stage to controlling in accordance with the second stage when an occurrence of an event has been recognized.

19. The electrosurgical generator according to claim 1, wherein the at least one processor is further configured to regulate parameters of the electrosurgical energy selected from the group of parameters consisting of voltage, current, resistance, intensity, power, frequency, amplitude, and pulse parameters, wherein the pulse parameters are selected from the group of pulse parameters consisting of pulse width, duty cycle, crest factor, and repetition rate.

20. An electrosurgical generator configured to generate electrosurgical energy delivered to a patient for performing an electrosurgical procedure for sealing tissue, the generator comprising:

at least one sensor configured to sense at least one of a physical and electrical property related to the delivery of the electrosurgical energy;

at least one processor configured to receive sensed data corresponding to the at least one of the physical and electrical property and to process at least a portion of said received sensed data to control the electrosurgical generator, the at least one processor further configured to continuously compare the received sensed data to a mapping having a time-based plot of desired progression of the at least one of the physical and electrical property, the at least one processor configured to generate at least one control signal as a function of the comparison of the sensed data with the mapping for regulating electrosurgical energy output from said electrosurgical generator;

the at least one processor further configured to receive and process additional data and generate the at least one control signal in accordance with the received and processed additional data, wherein the additional data is selected from at least one of an actual optical characteristic of tissue proximate the surgical site selected from the group of characteristics consisting of absorption properties, reflectivity properties, transmissivity properties and opaqueness properties, actual volume of tissue between jaws of an electrosurgical instrument delivering the electrosurgical energy, an actual elastomeric property of tissue proximate the surgical site, actual viability of tissue proximate the surgical site, actual pressure reactivity of tissue proximate the surgical site, actual moisture content level of tissue proximate the surgical site;

actual thickness of tissue proximate the surgical site, actual gap between electrodes of the electrosurgical instrument, actual pressure applied by the electrosurgical instrument, actual leakage current, a desired optical characteristic of tissue proximate the surgical site selected from the group of characteristics consisting of absorption properties, reflectivity properties, transmissivity properties and opaqueness properties, desired volume of tissue between jaws of the electrosurgical instrument, a desired elastomeric property of tissue proximate the surgical site, desired viability of tissue proximate the surgical site, desired viability of sealed tissue, desired pressure reactivity of tissue proximate the surgical site, desired moisture content level of tissue proximate the surgical site;

desired thickness of tissue proximate the surgical site, desired gap between electrodes of the electrosurgical instrument, desired pressure applied by the electrosurgical instrument type of electrosurgical instrument, type of tissue being sealed, patient profile data, patient'"'"'s disease profile data, at least one mapping of the at least one mapping, allowed leakage current, applied voltage, applied current, at least one predetermined threshold value and at least one target parameter for a corresponding parameter of the electrosurgical energy;

the at least one processor further configured to determine a change in values of the data over a variable a rate of change of the data over the variable and a change of rate of change of the data over the variable, and to determine when an event has occurred, the event being selected from the group of events consisting of exceeding a predetermined threshold value by the data, by the change in values of the data over the variable, by the rate of change of the data over the variable, by the change of the rate of change of the data over the variable, by a difference between the data and a predetermined value, by a determined seal quality value, by a determined seal completion value, by a difference between the sensed data and a corresponding target value obtained from the at least one mapping, and by a timing value generated by a timing device; and

the at least one processor further configured to determine when the quality of a seal is below a predetermined threshold level, and upon determining that the seal quality is below the predetermined threshold level the at least one processor initiates a new electrosurgical procedure for sealing tissue.

21. The electrosurgical generator according to claim 20, wherein the mapping is selected from the group of mappings consisting of a look-up table, a function and a continuous value mapping.

22. The electrosurgical generator according to claim 20, wherein the at least one of the physical and electrical property is selected from the group of properties consisting of temperature, impedance, current, power and voltage of the tissue proximate the surgical site.

23. The electrosurgical generator according to claim 20, wherein the at least one processor is further configured to determine imminent damage to tissue proximate the surgical site, actual damage to tissue proximate the surgical site, imminent thermal spread to tissue proximate the surgical site, and actual thermal spread to tissue proximate the surgical site.

24. The electrosurgical generator according to claim 23, wherein upon determining at least one of the imminent damage, the actual damage, the imminent thermal spread, and the actual thermal spread, the at least one processor performs at least one of controlling the electrosurgical generator for regulating the output of the electrosurgical generator by at least one of reducing output electrosurgical energy and discontinuing output of electrosurgical energy and generating at least one additional control signal for controlling an indicator device for notifying an operator.

25. The electrosurgical generator according to claim 20, wherein the additional data is at least one of sensed and user entered.

26. The electrosurgical generator according to claim 20, wherein the additional data is at least one of received and processed at a pre-surgical time before beginning the electrosurgical procedure and a concurrent-surgical time during the electrosurgical procedure.

27. The electrosurgical generator according to claim 20, wherein mapping includes a continuous value mapping having a target curve plotted over a variable, wherein at a respective point on the target curve the target curve has a target slope and during the procedure a rate of change of the sensed data is compared to the target slope for a respective point on the target curve that corresponds to a condition of the variable when the data was sensed, and the controlling of the electrosurgical generator is in accordance with the results of the comparison.

28. The electrosurgical generator according to claim 27, wherein the target curve includes at least a first stage having a first target slope and second stage having a second target slope, and the first and second target slopes are different, and the controlling of the electrosurgical generator includes changing control from controlling in accordance with the first stage to controlling in accordance with the second stage when an occurrence of an event has been recognized.

29. The electrosurgical generator according to claim 20, wherein the at least one processor is further configured to determine the tissue type.

30. The electrosurgical generator according to claim 20, wherein at least one of the received sensed data and additional data is received at a pre-surgical time before beginning the procedure, and the at least one of the received sensed data and additional data responds to application of a pre-surgical electrosurgical energy applied before beginning the electrosurgical procedure.

31. The electrosurgical generator according to claim 20, wherein the at least one processor is further configured to control the electrosurgical energy by initializing parameters of the electrosurgical energy before beginning the electrosurgical procedure.

32. The electrosurgical generator according to claim 20, wherein the initiating the new electrosurgical procedure includes using at least one of the sensed data and parameter settings of the electrosurgical energy from the previous procedure for controlling the electrosurgical generator for the new procedure.

33. The electrosurgical generator according to claim 20, further comprising an indicator device configured to indicate to an operator at least one of the determined seal quality, and a representation of a comparison of the sensed data with the mapping.

34. The electrosurgical generator according to claim 20, wherein the at least one processor is further configured to regulate parameters of the electrosurgical energy selected from the group of parameters consisting of voltage, current, resistance, intensity, power, frequency, amplitude, and pulse parameters, wherein the pulse parameters are selected from the group of pulse parameters consisting of pulse width, duty cycle, crest factor, and repetition rate.

35. The electrosurgical generator according to claim 20, wherein the at least one processor is further configured to select at least one mapping from a plurality of accessible mappings.