Electrosurgical Apparatus with Integrated Energy Sensing at Tissue Site

• US 20130197503A1
• Filed: 01/30/2012
• Published: 08/01/2013
• Est. Priority Date: 01/30/2012
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Tyco Healthcare Group LP (Medtronic Plc)
• Inventors: Orszulak, James H.
• Granted Patent: US 9,693,816 B2
• Time in Patent Office: Days
• US Class Current: 606/33
• CPC Class Codes: A61B 18/1206 Generators 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 2018/00095 high, i.e. heat conducting
• CPC Class Codes: A61B 2018/00755 Resistance or impedance
• CPC Class Codes: A61B 2018/00791 Temperature
• CPC Class Codes: A61B 2018/00827 Current
• CPC Class Codes: A61B 2018/00892 Voltage
• CPC Class Codes: A61B 2018/00988 Means for storing information, e.g. calibration constants, or for preventing excessive use, e.g. usage, service life counter

Abstract

An electrosurgical system is disclosed. The system includes an electrosurgical instrument having at least one electrode configured as a first sensor for measuring a voltage drop therethrough and a temperature sensor for a thermal sensor configured to measure a temperature difference across the at least one electrode; and a generator including an output stage coupled to the at least one electrode, the output stage configured to generate radio frequency energy; and a controller configured to determine actual radio frequency current based on the voltage drop and electrical resistivity of the at least one electrode and radio frequency power based on the measured temperature difference and the thermal conductivity of the at least one electrode.

Claims

1. An electrosurgical system, comprising:

an electrosurgical instrument including at least one electrode configured as a first sensor for measuring a voltage drop therethrough; and

a generator including;

an output stage coupled to the at least one electrode, the output stage configured to generate radio frequency energy; and

a controller configured to determine actual radio frequency current based on the voltage drop and electrical resistivity of the at least one electrode.

2. The electrosurgical system according to claim 1, wherein the generator further includes a non-transitory storage medium readable by the controller, the non-transitory storage medium configured to store the electrical resistivity of the at least one electrode.

3. The electrosurgical system according to claim 2, wherein the electrosurgical instrument further includes a thermal sensor coupled to the at least one electrode, the thermal sensor configured to measure a temperature difference across the at least one electrode.

4. The electrosurgical system according to claim 3, wherein the non-transitory storage medium is configured to store thermal conductivity of the at least one electrode.

5. The electrosurgical system according to claim 4, wherein the controller is further configured to determine power based on the measured temperature difference and the thermal conductivity of the at least one electrode.

6. The electrosurgical system according to claim 5, wherein the controller is further configured to determine tissue impedance based on the calculated power and current.

7. The electrosurgical system according to claim 1, wherein the generator further includes at least one active output terminal coupled to an active lead and a return output terminal coupled to a return lead, the electrosurgical instrument is coupled to the active lead and the return lead, and the first sensor is coupled to the generator through a sensor lead.

8. The electrosurgical system according to claim 7, further comprising:

an electrosurgical cable including a dielectric core, wherein the sensor lead is disposed within the dielectric core and at least a portion of each of the active lead and the return lead are wound in a double helix about the dielectric core to minimize an electrical field generated thereby.

9. An electrosurgical system, comprising:

an electrosurgical instrument including;

an electrosurgical instrument including at least one electrode configured as a first sensor for measuring a voltage drop therethrough; and

a thermal sensor coupled to the at least one electrode, the thermal sensor configured to measure a temperature difference across the at least one electrode; and

a generator including;

an output stage coupled to the at least one electrode, the output stage configured to generate radio frequency energy; and

a controller configured to determine actual radio frequency current based on the voltage drop and electrical resistivity of the at least one electrode.

10. The electrosurgical system according to claim 9, wherein the generator further includes a non-transitory storage medium readable by the controller, the non-transitory storage medium configured to store the electrical resistivity value and thermal conductivity of the at least one electrode.

11. The electrosurgical system according to claim 10, wherein the controller is further configured to determine power based on the measured temperature difference and the thermal conductivity of the at least one electrode.

12. The electrosurgical system according to claim 11, wherein the controller is further configured to determine tissue impedance based on the calculated power and current.

13. The electrosurgical system according to claim 9, wherein the generator further includes at least one active output terminal coupled to an active lead and a return output terminal coupled to a return lead, the electrosurgical instrument is coupled to the active lead and the return lead, and each of the voltage and thermal sensors is coupled to the generator through a sensor lead.

14. The electrosurgical system according to claim 13, further comprising:

an electrosurgical cable including a dielectric core, wherein the sensor leads are disposed within the dielectric core and at least a portion of each of the active lead and the return lead are wound in a double helix about the dielectric core to minimize an electrical field generated thereby.

15. The electrosurgical system according to claim 9, wherein the electrosurgical instrument is an electrosurgical forceps including at least one shaft member having an end effector disposed at a distal end thereof, the end effector including two jaw members movable from a first position in spaced relation relative to one another to at least one subsequent position wherein the jaw members cooperate to grasp tissue therebetween, each of the jaw members including an electrically conductive sealing surface forming the at least one electrode, wherein one electrically conductive sealing surface is coupled to the active lead and another electrically conductive sealing surface is coupled to the return lead.

16. The electrosurgical system according to claim 15, wherein the voltage and thermal sensors are disposed within at least one of the jaw members.

17. A method comprising:

measuring a voltage drop through at least one electrode of an electrosurgical instrument, the electrosurgical instrument being coupled to a generator;

storing electrical resistivity value of the at least one electrode in a non-transitory storage medium readable by a controller; and

determining actual radio frequency current based on the voltage drop and electrical resistivity of the at least one electrode.

18. The method according to claim 17, further comprising:

storing a thermal conductivity value of the at least one electrode in a non-transitory storage medium readable by a controller;

measuring temperature of the at least one electrode; and

determining power based on the measured temperature difference and the thermal conductivity of the at least one electrode.

19. The method according to claim 18, further comprising:

determining tissue impedance based on the calculated power and current.