Electrosurgical system and method having enhanced temperature measurement

• US 8,696,659 B2
• Filed: 04/30/2010
• Issued: 04/15/2014
• Est. Priority Date: 04/30/2010
• Status: Active Grant

• Current Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Original Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Inventors: Marion, Duane W.
• Primary Examiner(s): Peffley, Michael
• Assistant Examiner(s): VAHDAT, KHADIJEH A
• Application Number:
  US12/771,129
• Publication Number:
  US 20110270242A1
• Time in Patent Office: 1,446 Days
• Field of Search: 606 27- 52, 607/102, 604/19, 604/114
• US Class Current: 606/34
• CPC Class Codes: A61B 18/1233 with circuits for assuring patient safety
• CPC Class Codes: A61B 18/148 having a short, rigid shaft for accessing the inner body transcutaneously, e.g. for neurosurgery or arthroscopy
• CPC Class Codes: A61B 2017/00084 Temperature
• CPC Class Codes: A61B 2017/00088 using thermistors
• CPC Class Codes: A61B 2018/00011 with fluids
• CPC Class Codes: A61B 2018/00702 Power or energy
• CPC Class Codes: A61B 2018/00744 Fluid flow
• CPC Class Codes: A61B 2018/00767 Voltage
• 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 2218/007 Aspiration
• CPC Class Codes: A61B 90/06 Measuring instruments not otherwise provided for

Abstract

Electrosurgical 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. A controller automatically suspends energy delivery for one or more periods of time while the temperature is monitored.

Claims

1. An electrosurgical method for monitoring temperature during an electrosurgical procedure to ablate soft tissue comprising:

delivering high frequency energy to an active electrode terminal located at a distal end of an electrosurgical probe, said active electrode terminal being positioned in electrically conductive fluid during the electrosurgical procedure and wherein a current flow path from the active electrode terminal, through the electrically conductive fluid, to a return electrode is created when the high frequency energy is delivered;

monitoring a temperature signal indicative of a temperature of the electrically conductive fluid;

automatically suspending the delivering step for at least one suspension period;

during the at least one suspension period, measuring or calculating the temperature of the electrically conductive fluid from the temperature signal; and

repeating the step of delivering upon completion of the at least one suspension period, wherein the at least one suspension period has a duration sufficient for an electrical noise associated with the step of delivering the high frequency energy to diminish and to allow the temperature signal to stabilize.

2. The method of claim 1 wherein said at least one suspension period is at least 250 ms.

3. The method of claim 1 further comprising:

circulating the electrically conductive fluid to a target site at a flowrate;

comparing the temperature signal indicative of the temperature of the electrically conductive fluid to a desired temperature range; and

adjusting the flowrate based on the measured or calculated temperature of the electrically conductive fluid.

4. The method of claim 1 wherein said delivering step forms a plasma in the vicinity of the active electrode terminal.

5. The method of claim 1 wherein said soft tissue is within a joint.

6. The method of claim 1 wherein said automatically suspending step is performed by reducing the high frequency energy so as to reduce an applied voltage difference between the active electrode terminal and the return electrode to less than 100 volts.

7. An electrosurgical method for monitoring temperature during an electrosurgical procedure to ablate soft tissue comprising:

delivering high frequency energy to an active electrode terminal located at a distal end of an electrosurgical probe, said active electrode terminal being positioned in electrically conductive fluid during the electrosurgical procedure and wherein a current flow path from the active electrode terminal, through the electrically conductive fluid, to a return electrode is created when the high frequency energy is delivered;

adjusting the high frequency energy for at least one suspension period;

during the at least one suspension period, monitoring a temperature signal indicative of the temperature of the electrically conductive fluid; and

repeating the step of delivering upon completion of the at least one suspension period, wherein the at least one suspension period has a duration sufficient for an electrical noise associated with the step of delivering the high frequency energy to diminish and to allow the temperature signal to stabilize.

8. The method of claim 7 wherein the step of adjusting is done automatically by a controller in electrical communication with the electrosurgical probe.

9. The method of claim 7 wherein adjusting the high frequency energy comprises suspending the high frequency energy delivery for the at least one suspension period.

10. The method of claim 7 wherein adjusting the high frequency energy comprises reducing the high frequency energy delivery for the at least one suspension period.

11. The method of claim 7 wherein monitoring the temperature signal indicative of the temperature of the electrically conductive fluid further comprises measuring or calculating a sensed temperature of the electrically conductive fluid.