Systems and methods for limiting joint temperature

• US 9,452,008 B2
• Filed: 12/07/2012
• Issued: 09/27/2016
• Est. Priority Date: 12/12/2008
• Status: Active Grant

• Current Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Original Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Inventors: DeCou, Robert, Marion, Duane W., Knudsen, Katherine
• Primary Examiner(s): Bouchelle, Laura
• Assistant Examiner(s): Snyder, Melissa A
• Application Number:
  US13/708,246
• Publication Number:
  US 20130116689A1
• Time in Patent Office: 1,390 Days
• Field of Search: 606/32, 606/34, 606 38- 40, 606/41, 607/102, 604/114, 604/19
• US Class Current: 1/1
• CPC Class Codes: A61B 18/1206 Generators therefor
• CPC Class Codes: A61B 18/1233 with circuits for assuring patient safety
• CPC Class Codes: A61B 18/14 Probes or electrodes therefor
• CPC Class Codes: A61B 2017/00084 Temperature
• CPC Class Codes: A61B 2018/00583 Coblation, i.e. ablation using a cold plasma
• CPC Class Codes: A61B 2018/00702 Power or energy
• CPC Class Codes: A61B 2018/00791 Temperature
• CPC Class Codes: A61B 2018/1472 for use with liquid electrolyte, e.g. virtual electrodes
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• CPC Class Codes: A61B 5/4528 Joints A61B5/4533, A61B5/4538 take precedence

Abstract

Joint temperature monitoring and control systems and methods are described herein in which the temperature of a fluid within a body or joint space is determined and/or monitored despite the energy generated during treatment by an ablation probe. One or more temperature sensors are positioned along the probe proximally of the electrode assembly and measure the temperature of an electrically conductive fluid without being overly influenced by the surgical effect occurring proximate the electrode assembly. The controller coupled to the probe can also be configured to set temperature limits and treatment times as well as moderating joint temperature by altering the electrically conductive fluid flow.

Claims

1. An apparatus for treating tissue at a target site within a body or joint space comprising:

an electrosurgical probe having a shaft with a distal end and a proximal end, the electrosurgical probe further comprising;

an active electrode disposed near the distal end;

a return electrode disposed on the shaft; and

a temperature sensor disposed on the shaft spaced away from the active electrode and the return electrode for measuring the temperature of an electrically conductive fluid located in the body or joint space, and wherein the temperature sensor is electrically insulated from the electrically conductive fluid;

a high frequency power supply, the high frequency power supply coupled to the active electrode, the high frequency power supply configured to provide an electrical energy output between the active electrode and the return electrode.

2. The apparatus of claim 1 wherein the temperature sensor is disposed at least 5 mm away from the distal end.

3. The apparatus of claim 1 wherein the electrically conductive fluid located at the target site provides a current path between the active electrode and the return electrode.

4. The apparatus of claim 1, the high frequency power supply further comprising an analog-to-digital converter for converting measured temperature to a digital signal.

5. The apparatus of claim 1 wherein the temperature sensor is at least one selected from the group consisting of:

a thermocouple;

a T type thermocouple;

a thermistor;

a resistance detector.

6. The apparatus of claim 1, wherein the target site comprises a joint in a patient body.

7. The apparatus of claim 1, further comprising a fluid delivery element for delivering the electrically conductive fluid to the target site.

8. The apparatus of claim 7 wherein the fluid delivery element comprises a pump, and wherein the pump is operable to control fluid inflow to the target site and fluid outflow from the target site.

9. The apparatus of claim 8 wherein the pump regulates the fluid inflow and the fluid outflow in order to maintain the temperature of the fluid below a predetermined level.

10. The apparatus of claim 1 wherein temperature sensor is disposed proximally from the electrodes, and is between 3 mm and 20 mm, inclusive, away from the distal end of the shaft.

11. The apparatus of claim 1 wherein the high frequency power supply is configured to generate plasma proximate the active electrode.

12. The apparatus of claim 1 further comprising:

a microprocessor for controlling the high frequency power supply in accordance with an output of the temperature sensor, wherein the microprocessor is programmed with a series of temperature limits, and is configured to generate an alarm if the temperature sensor measures temperature of the electrically conductive fluid in excess of a first limit, and to reduce or deactivate the electrical energy output if the temperature sensor measures temperature of the electrically conductive fluid in excess of a second limit.

13. The apparatus of claim 12 wherein the microprocessor is configured for monitoring and controlling a power output from the active electrode in accordance with the temperature of the electrically conductive fluid.

14. The apparatus of claim 12 wherein the microprocessor is configured for a user to select the first limit of the series of temperature limits.

15. A method for treating tissue at a target site comprising:

delivering an electrically conductive fluid to the target site in a patient'"'"'s body or joint space;

positioning an electrosurgical instrument adjacent to the target site, the electrosurgical instrument comprising an elongate shaft, an active electrode disposed on the elongate shaft and a return electrode disposed on the elongate shaft;

generating a plasma proximate the active electrode by applying a high frequency voltage between the active electrode and the return electrode, wherein the electrically conductive fluid provides a conductive path between the active electrode and the return electrode; and

sensing a temperature of the electrically conductive fluid in the body or joint space, the sensing by a temperature sensor disposed on an exterior surface of the elongate shaft, the temperature sensor disposed proximally from the electrodes, and the temperature sensor between 3 mm and 20 mm, inclusive, away from a distal end of the elongate shaft.

16. The method of claim 15, further comprising:

delivering a circulating flow of the electrically conductive fluid to the body or joint space;

comparing the temperature to a desired temperature range; and

adjusting the circulating flow of the electrically conductive fluid based on the temperature.

17. The method of claim 15, wherein the step of sensing further comprises correlating a target tissue temperature from the temperature of the electrically conductive fluid.

18. The method of claim 15 further comprising:

generating an alarm upon the temperature of the electrically conductive fluid exceeding a first limit; and

controlling the high frequency voltage applied between the active electrode and the return electrode upon the temperature of the electrically conductive fluid exceeding a second limit.

19. The method of claim 18, further comprising:

comparing the temperature to a desired temperature range; and

adjusting the voltage based on the temperature.

20. The method of claim 19, wherein the desired temperature range is selected according to a tissue type or a procedure type.

21. The method of claim 18, further comprising selecting, by a user, the first limit within a series of temperature limits.

22. A tissue treatment apparatus, comprising:

an electrosurgical probe having an elongate shaft with an active electrode positioned near or at a distal end of the elongate shaft, and a return electrode positioned on the elongate shaft proximally of the active electrode; and

at least one temperature sensor spaced away from the active and return electrodes, the at least one temperature sensor within or along the shaft, the at least one temperature sensor configured to detect a temperature of an electrically conductive fluid, and the at least one temperature sensor electrically insulated from the electrically conductive fluid.

23. The apparatus of claim 22 wherein the at least one temperature sensor comprises a thermocouple, thermistor, or resistance temperature detector.

24. The apparatus of claim 22 wherein the at least one temperature sensor is positioned proximally from the return electrode by a distance of at least 5 mm.

25. The apparatus of claim 22 wherein the at least one temperature sensor is thermally insulated from the elongate shaft.

26. The apparatus of claim 22 further comprising a controller coupled to the electrosurgical probe.

27. The apparatus of claim 26, wherein the controller further comprises:

a microprocessor for controlling the apparatus; and

an analog-to-digital converter for converting the temperature of the electrically conductive fluid to a digital signal readable by the microprocessor.

28. The apparatus of claim 22 further comprising:

a microprocessor coupled to the at least one temperature sensor and programmed with a series of temperature limits, the microprocessor configured to generate an alarm if the temperature sensor detects temperature of the electrically conductive fluid in excess of a first limit, and to reduce or deactivate an electrical energy output if the temperature sensor detects temperature of the electrically conductive fluid in excess of a second limit.

29. The apparatus of claim 28 wherein the microprocessor is pre-programmed with a series of temperature limits.

30. The apparatus of claim 28 wherein the microprocessor is configured for a user to select the first limit of the series of temperature limits.

31. The apparatus of claim 22 further comprising a high frequency power supply, the high frequency power supply coupled to the active electrode and the return electrode, and the high frequency power supply configured to generate plasma proximate the active electrode by supplying an electrical energy output between the active electrode and the return electrode.

32. The apparatus of claim 22 wherein the at least one temperature sensor is positioned proximally from the active and return electrodes, and the temperature sensor is between 3 mm and 20 mm, inclusive, away from the distal end of the elongate shaft.

33. A tissue treatment apparatus, comprising:

an electrosurgical probe that defines

an elongate shaft that defines a distal end and a proximal end;

a suction lumen within the elongate shaft, and the suction lumen has a distal opening;

an active electrode disposed on the elongate shaft at the distal end of the elongate shaft, and the active electrode disposed over the distal opening;

a return electrode disposed on the elongate shaft proximally of the active electrode;

a tubing layer telescoped over and covering a portion of the elongate shaft, the tubing layer disposed proximal of the active and return electrodes, the tubing layer extends toward the proximal end of the elongate shaft, and the tubing layer is electrically insulative; and

a temperature sensor disposed on the elongate shaft proximally of the return electrode, and the temperature sensor disposed beneath the tubing layer;

a high frequency power supply, the high frequency power supply coupled to the active electrode, the high frequency power supply configured to generate plasma proximate the active electrode by supplying an electrical energy output between the active electrode and the return electrode.

34. The tissue treatment apparatus of claim 33 wherein the return electrode is concentrically disposed on the elongate shaft.

35. The tissue treatment apparatus of claim 33 wherein temperature sensor is at least 5 mm away from the distal end of the elongate shaft.

36. The tissue treatment apparatus of claim 33 further comprising:

a thermally insulative layer disposed between the temperature sensor and the elongate shaft and

wherein the temperature sensor is between 3 mm and 20 mm, inclusive, away from the distal end of the elongate shaft.