Method and system for controlling output of RF medical generator

• US 20050203504A1
• Filed: 01/27/2005
• Published: 09/15/2005
• Est. Priority Date: 10/23/1998
• Status: Active Grant

• Current Assignee: Covidien AG (Medtronic Plc)
• Original Assignee: Covidien AG (Medtronic Plc)
• Inventors: Shields, Chelsea, James, Jeremy S., Wham, Robert H., Tetzlaff, Philip M.
• Granted Patent: US 7,901,400 B2
• Time in Patent Office: Days
• 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. A control system associated with an electrosurgical generator generating electrosurgical energy which is delivered to a patient for performing an electrosurgical procedure for sealing tissue, the system comprising:

a control module executable on at least one processor for receiving sensed data corresponding to at least one physical or electrical property related to delivery of the electrosurgical energy, the sensed data sensed by at least one sensor, processing at least a portion of said received sensed data and controlling the electrosurgical generator including generating at least one corresponding control signal in accordance with said processed sensed data for regulating electrosurgical energy output from said electrosurgical generator, the controlling the electrosurgical generator further including 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.

2. The control system according to claim 1, wherein the sensing, receiving, processing and generating is continuous for real-time regulation of the electrosurgical energy.

3. The control system according to claim 1, wherein the at least one mapping is selected from the group of mappings consisting of a look-up table, a function and a continuous value mapping.

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

5. The control system according to claim 1, wherein the control module further

receives and processes additional data and generates 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 control system according to claim 5, wherein the processing of data of the received sensed data and additional data includes determining change in values of the data over a variable, rate of change of the data over the variable, a change of rate of change of the data over the variable and determining when an event has occurred 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 control system according to claim 6, wherein the variable is selected from the group of variables consisting of time and impedance across the tissue proximate the surgical site.

8. The control system according to claim 5, wherein processing of data of the received sensed data and additional data includes determining 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.

9. The control system according to claim 5, wherein the additional data is at least one of sensed and user entered.

10. The control system 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.

11. The control system according to claim 5, wherein processing of the received sensed data and additional data includes selecting at least one mapping from a plurality of accessible mappings.

12. The control system according to claim 6, wherein the at least one 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.

13. The control system according to claim 12, 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.

14. The control system according to claim 5, wherein processing of data of the received sensed data and additional data includes determining the tissue type.

15. The control system according to claim 6, wherein at least one of completion of a seal and quality of the seal is determined in accordance with the occurrence of an event.

16. The control system 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.

17. The control system according to claim 5, wherein the controlling the electrosurgical energy includes initializing parameters of the electrosurgical energy before beginning the electrosurgical procedure.

18. The control system according to claim 8, wherein upon determining at least one of the imminent damage, the actual damage, the imminent thermal spread, and the actual thermal spread, the control module 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.

19. The control system according to claim 15, wherein the control module further determines 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 controlling includes initiating a new electrosurgical procedure for sealing tissue.

20. The control system according to claim 19, 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.

21. The control system according to claim 15, wherein the system further comprises an indicator device for indicating to an operator at least one of the determined seal quality, and a representation of a comparison of the sensed data corresponding to the at least one control variable to the at least one mapping.

22. The control system according to claim 1, wherein the electrosurgical energy is selected from the group of energies consisting of RF, resistive heat energy, ultrasound and laser.

23. The control system according to claim 1, wherein regulating the electrosurgical energy includes regulating 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.

24. The control system according to claim 22, wherein when the electrosurgical energy is resistive heat energy, controlling the electrosurgical generator further includes controlling resistivity and current levels associated with the electrosurgical generator.

25. The control system according to claim 1, wherein the at least one control variable is selected from at least one of temperature, impedance, current, voltage and power across tissue proximate the surgical site.

26. The control system according to claim 25, wherein the control variable is selected by comparing sensed impedance across tissue proximate the surgical site to at least one predetermined threshold value.

27. The control system according to claim 1, wherein the at least one control variable is selected from the group of variables consisting of current, voltage and power, the at least one mapping maps the control variable as a function of impedance, the control module determines a differential between the actual value for a respective control variable as sensed by the at least one sensor and a target value for the respective control variable as mapped at a point that corresponds to the actual impedance value as sensed by the at least one sensor, and wherein the control module controls the electrosurgical generator in accordance with the determined differential.

28. The control system according to claim 1, wherein the control module includes a first control module for controlling an inner control loop for controlling the electrosurgical generator in accordance with a first mapping of the at least one 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 at least one mapping.

29. The control system according to claim 28, wherein the first mapping maps a respective control variable selected from one of current, voltage and power as a function of impedance, the control module determines a differential between an actual value for the respective control variable as sensed by the at least one sensor and a target value for the respective control variable as mapped at a point that corresponds to the actual impedance value as sensed by the at least one sensor, and wherein the control module controls the electrosurgical generator in accordance with the determined differential.

30. The control system according to claim 29, wherein the second mapping maps a respective control variable selected from one of current, voltage, power, impedance and temperature as a function of time, the control module determines a differential between an actual value for the respective control variable as sensed by the at least one sensor and a target value for the respective control variable as mapped at a point that corresponds to the time of the sensing of the respective control variable, and wherein the second control module controls the first control module in accordance with the differential.

31. The control system according to claim 30, wherein the second control module controls the first control module by adjusting the first mapping in accordance with the differential.

32. The control system according to claim 30, wherein the second control module generates a proportional integral derivative (PID) control signal in accordance with the differential and controls the first module in accordance with the PID control signal.

33. The control system according to claim 1,

wherein an electrosurgical instrument delivering the electrosurgical energy for treating tissue includes an array of electrodes configured as micro-sealing pads, wherein electrosurgical energy output by the electrosurgical controller flows through a respective micro-sealing pad for applying electrosurgical energy to a limited area of tissue for sealing the area of tissue for forming a micro-seal, wherein at least one area of tissue in between respective micro-sealing pads of the array of micro-sealing pads remains substantially viable for creating an intermittent pattern of individual micro-seals across the tissue treated by the electrosurgical instrument;

and

wherein the control module further controls delivery of electrosurgical energy to individual micro-sealing pads of the array of micro-sealing pads for at least one of selecting at least one micro-sealing pad to receive electrosurgical energy and providing electrosurgical energy having a first potential to a first selected at least one micro-sealing pad and a second potential to a second selected at least one micro-sealing pad.

34. The control system according to claim 33, wherein a first electrical path is provided for delivery of the electrosurgical energy having the first potential and a second electrical path is provided for delivery the electrosurgical energy having the second potential, and the first electrical path has a first resistivity and the second path has a second resistivity.

35. The control system according to claim 33, wherein the control module further controls delivery of electrosurgical energy to the individual micro-sealing pads in accordance with at least one of sensed viability of the tissue proximate the surgical site and desired viability of the tissue proximate the surgical site.

36. The control system according to claim 33, wherein a quality of the seal is determined in accordance with a quantitative relationship between substantially viable tissue and substantially nonviable tissue proximate the tissue site.

37. The control system according to claim 36, wherein the control module determines if the seal quality is below a predetermined threshold value, and if so a new electrosurgical procedure is initiated, wherein the control module controls the delivery of electrosurgical energy to the individual micro-sealing pads by at least one of selecting a different at least one micro-sealing pad and changing at least one of the first and second potentials.

38. The control system according to claim 33, wherein the control module controls delivery of the electrosurgical energy to the individual micro-sealing pads in accordance with sensed tissue thickness along a length of the jaws of electrosurgical upon which the micro-sealing pads are disposed.

41. The control system according to claim 33, wherein the electrosurgical instrument further includes a cutting element configured to cut tissue, and the control module determines when a seal is complete and controls the cutting element to sever tissue included in the seal upon determination that the seal is complete.

43. The method according to claim 41, further comprising the step of adjusting at least one mechanical parameter of an electrosurgical instrument delivering the generated electrosurgical energy to the patient, including adjusting at least one of pressure applied by at least one electrode of the electrosurgical instrument through which the electrosurgical energy is delivered, and adjusting a gap between at least two electrodes of the at least one electrode, wherein the controlling of the electrosurgical generator and the adjusting of the at least one mechanical parameter are coordinated for achieving a desired tissue effect.

39. A control system associated with an electrosurgical generator generating electrosurgical energy which is delivered to a patient for performing an electrosurgical procedure for sealing tissue, the system comprising:

a control module executable on at least one processor for controlling an electrosurgical instrument delivering electrosurgical energy generated by the electrosurgical generator, wherein the electrosurgical instrument includes an array of electrodes configured as micro-sealing pads, wherein electrosurgical energy output by the electrosurgical generator flows through a respective micro-sealing pad for applying electrosurgical energy to a limited area of tissue for sealing the area of tissue for forming a micro-seal, wherein at least one area of tissue in between respective micro-sealing pads of the array of micro-sealing pads remains substantially viable for creating an intermittent pattern of individual micro-seals across tissue treated by the electrosurgical instrument; and

wherein the control module further controls delivery of electrosurgical energy to individual micro-sealing pads of the array of micro-sealing pads for at least one of selecting at least one micro-sealing pad to receive electrosurgical energy and providing electrosurgical energy having a first electrical potential to a first selected at least one micro-sealing pad and a second electrical potential to a second selected at least one micro-sealing pad.

40. (canceled)

42. A method for controlling an electrosurgical generator generating electrosurgical energy which is delivered to a patient for performing an electrosurgical procedure for sealing tissue, comprising the steps of:

continually sensing at least one physical or electrical property proximate the surgical site;

generating sensed data corresponding to the sensing;

processing at least a portion of said sensed data; and

controlling the electrosurgical generator comprising the steps of;

generating at least one corresponding control signal in accordance with said processed sensed data for regulating electrosurgical energy output from said electrosurgical generator; and

regulating at least one control variable to follow at least one mapping for optimizing the tissue sealing, wherein a respective control variable of the at least one control variable corresponds to sensed data which corresponds to a property of the at least one physical or electrical property.