Method for treating articular cartilage defects

• US 6,416,507 B1
• Filed: 01/18/2000
• Issued: 07/09/2002
• Est. Priority Date: 01/07/1992
• Status: Expired due to Fees

• Current Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Original Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Inventors: Eggers, Philip E., Thapliyal, Hira V.
• Primary Examiner(s): COHEN, LEE S
• Application Number:
  US09/484,087
• Time in Patent Office: 903 Days
• Field of Search: 606/32, 606/41, 606/46, 606/49, 607/98, 607/99, 607/105, 607/113, 604/114
• US Class Current: 606/32
• CPC Class Codes: A61B 18/042 using additional gas becoming plasma
• CPC Class Codes: A61B 18/12 by passing a current through the tissue to be heated, e.g. high-frequency current
• CPC Class Codes: A61B 18/1206 Generators therefor
• CPC Class Codes: A61B 18/1402 Probes for open surgery
• 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 18/1482 having a long rigid shaft for accessing the inner body transcutaneously in minimal invasive surgery, e.g. laparoscopy
• CPC Class Codes: A61B 18/1485 having a short rigid shaft for accessing the inner body through natural openings
• CPC Class Codes: A61B 18/149 bow shaped or with rotatable body at cantilever end, e.g. for resectoscopes, or coagulating rollers
• CPC Class Codes: A61B 18/1492 having a flexible, catheter-like structure, e.g. for heart ablation A61B18/1477 takes precedence
• CPC Class Codes: A61B 2017/00026 Conductivity or impedance, e.g. of tissue
• CPC Class Codes: A61B 2017/00084 Temperature
• CPC Class Codes: A61B 2017/00097 one of the thermometric elements being an electrode or the heating element
• CPC Class Codes: A61B 2017/00101 using an array of thermosensors
• CPC Class Codes: A61B 2017/00106 ultrasonic
• CPC Class Codes: A61B 2017/00247 Making holes in the wall of the heart, e.g. laser Myocardial revascularization
• CPC Class Codes: A61B 2017/00292 mounted on or guided by flexible, e.g. catheter-like, means
• CPC Class Codes: A61B 2017/003 Steerable
• CPC Class Codes: A61B 2017/22001 Angioplasty, e.g. PCTA
• CPC Class Codes: A61B 2017/22038 with a guide wire
• CPC Class Codes: A61B 2018/00029 open
• CPC Class Codes: A61B 2018/00083 : low, i.e. electrically insulating
• CPC Class Codes: A61B 2018/00119 : with metal oxide nitride
• CPC Class Codes: A61B 2018/0016 : Energy applicators arranged in a two- or three dimensional array
• CPC Class Codes: A61B 2018/00178 : Electrical connectors
• CPC Class Codes: A61B 2018/00196 : reciprocating lengthwise
• CPC Class Codes: A61B 2018/00327 : Ear, nose or throat
• CPC Class Codes: A61B 2018/00392 : Transmyocardial revascularisation
• CPC Class Codes: A61B 2018/0047 : Upper parts of the skin, e.g. skin peeling or treatment of wrinkles
• CPC Class Codes: A61B 2018/00476 : Hair follicles
• CPC Class Codes: A61B 2018/00505 : Urinary tract
• CPC Class Codes: A61B 2018/00577 : Ablation
• CPC Class Codes: A61B 2018/00583 : Coblation, i.e. ablation using a cold plasma
• CPC Class Codes: A61B 2018/00601 : Cutting
• CPC Class Codes: A61B 2018/00642 : with feedback, i.e. closed loop control
• CPC Class Codes: A61B 2018/0066 : without feedback, i.e. open loop control
• CPC Class Codes: A61B 2018/00678 : upper
• CPC Class Codes: A61B 2018/00702 : Power or energy
• CPC Class Codes: A61B 2018/00726 : Duty cycle
• CPC Class Codes: A61B 2018/00738 : Depth, e.g. depth of ablation
• CPC Class Codes: A61B 2018/00755 : Resistance or impedance
• CPC Class Codes: A61B 2018/00761 : Duration
• CPC Class Codes: A61B 2018/00791 : Temperature
• CPC Class Codes: A61B 2018/00797 : measured by multiple temperature sensors
• CPC Class Codes: A61B 2018/00821 : measured by a thermocouple
• CPC Class Codes: A61B 2018/00827 : Current
• CPC Class Codes: A61B 2018/00875 : Resistance or impedance
• CPC Class Codes: A61B 2018/00886 : Duration
• CPC Class Codes: A61B 2018/00982 : combined with or comprising means for visual or photographic inspections inside the body, e.g. endoscopes
• CPC Class Codes: A61B 2018/1213 : creating an arc
• CPC Class Codes: A61B 2018/124 : switching the output to different electrodes, e.g. sequentially
• CPC Class Codes: A61B 2018/1246 : characterised by the output polarity
• CPC Class Codes: A61B 2018/1253 : monopolar
• CPC Class Codes: A61B 2018/126 : bipolar
• CPC Class Codes: A61B 2018/1273 : including multiple generators in one device
• CPC Class Codes: A61B 2018/1407 : Loop
• CPC Class Codes: A61B 2018/1467 : using more than two electrodes on a single probe
• CPC Class Codes: A61B 2018/1472 : for use with liquid electrolyte, e.g. virtual electrodes
• CPC Class Codes: A61B 2018/162 : located on the probe body
• CPC Class Codes: A61B 2018/165 : Multiple indifferent electrodes
• CPC Class Codes: A61B 2090/378 : using ultrasound
• CPC Class Codes: A61B 2090/3782 : transmitter or receiver in catheter or minimal invasive instrument
• CPC Class Codes: A61B 2218/002 : Irrigation
• CPC Class Codes: A61B 2218/007 : Aspiration
• CPC Class Codes: A61F 2/2493 : Transmyocardial revascularisation [TMR] devices
• CPC Class Codes: A61F 2/95 : Instruments specially adapted for placement or removal of stents or stent-grafts
• CPC Class Codes: A61M 25/0133 : Tip steering devices
• CPC Class Codes: A61M 25/0147 : with movable mechanical means, e.g. pull wires
• CPC Class Codes: A61M 25/0158 : with magnetic or electrical means, e.g. by using piezo materials, electroactive polymers, magnetic materials or by heating of shape memory materials

Abstract

An electrosurgical probe (10) comprises a shaft (13) having an electrode array (58) at its distal end and a connector (19) at its proximal end for coupling the electrode array to a high frequency power supply (28). The shaft includes a return electrode (56) recessed from its distal end and enclosed within an insulating jacket (18). The return electrode defines an inner passage (83) electrically connected to both the return electrode and the electrode array for passage of an electrically conducting liquid (50). By applying high frequency voltage to the electrode array and the return electrode, the electrically conducting liquid generates a current flow path between the return electrode and the electrode array so that target tissue may be cut or ablated. The probe is particularly useful in dry environments, such as the mouth or abdominal cavity, because the electrically conducting liquid provides the necessary return current path between the active and return electrodes.

Claims

1. A method for smoothing body structures comprising:

positioning an electrode terminal into at least close proximity with a target surface of a body structure at a target site in the presence of an electrically conductive fluid;

positioning a return electrode in close proximity to the body structure such that the return electrode is not in contact with said target surface;

applying high frequency voltage to the electrode terminal and the return electrode such that an electrical current flows from the electrode terminal, through the target site, and to the return electrode; and

smoothing the target surface of the body structure with the high frequency voltage.

2. The method of claim 1 wherein the body structure comprises articular cartilage on the surface of a condyle, the method comprising smoothing an irregular surface of the articular cartilage.

3. The method of claim 2 wherein the voltage is sufficient to smooth the irregular surface of the articular cartilage while minimizing the depth of ablation and necrosis in the articular cartilage.

4. The method of claim 2 further comprising providing sufficient voltage to the electrode terminal to ablate at least a portion of cartilage strands on the irregular surface of the articular cartilage to smooth said surface.

5. The method of claim 2 further comprising providing sufficient voltage to the electrode terminal to heat at least a portion of cartilage strands on the irregular surface of the articular cartilage to smooth said surface.

6. The method of claim 2 further comprising providing sufficient voltage to the electrode terminal to thermally soften at least a portion of the irregular surface of the articular cartilage to smooth said surface.

7. The method of claim 1 further comprising positioning the return electrode within the electrically conductive fluid to generate a current flow path between the electrode terminal and the return electrode.

8. The method of claim 7 further comprising immersing the target site within a volume of the electrically conductive fluid and positioning the return electrode within the volume of electrically conductive fluid to generate the current flow path between the target site and the return electrode.

9. The method of claim 8 wherein the electrically conductive fluid has originated from an external source outside of the patient'"'"'s body.

10. The method of claim 8 wherein the electrically conductive fluid comprises isotonic saline.

11. The method of claim 1 wherein the electrical current flows substantially through the electrically conductive fluid while minimizing electrical current flow passing through the body structure.

12. The method of claim 1 wherein at least a portion of the electrical current passes through the body structure.

13. The method of claim 1 wherein the electrode terminal comprises a single electrode disposed near the distal end of an instrument shaft.

14. The method of claim 1 wherein the electrode terminal includes an array of electrically isolated electrode terminals disposed near the distal end of an instrument shaft.

15. The method of claim 13 including independently controlling current flow from at least two electrode terminals based on electrical impedance between each electrode terminal and the return electrode.

16. The method of claim 1 wherein the return electrode is spaced from the electrode terminal such that when the electrode terminal is brought adjacent a tissue structure immersed in electrically conductive fluid, the return electrode is spaced from the tissue structure and the electrically conductive fluid completes a conduction path between the electrode terminal and the return electrode.

17. The method of claim 16 further comprising moving the electrode terminal transversely across the body structure.

18. The method as in claim 1 further including maintaining a space between the electrode terminal and the body structure during the applying step.

19. The method of claim 1 wherein the electrically conductive fluid is directed through a cannula into a body cavity, the electrode terminal and the return electrode being submerged in the fluid within the body cavity.

20. The method of claim 1 further comprising providing one or more electrode terminals surrounded by an insulating matrix to electrically isolate each terminal, the insulating matrix comprising an inorganic material.

21. The method of claim 1 wherein the high frequency voltage is greater than 10 volts RMS and less than 1000 volts RMS.

22. The method of claim 1 wherein the electrode terminal is disposed over a lateral surface of an electrode support member.

23. The method of claim 1 wherein the electrode terminal has a shape selected from the group consisting essentially of flat, concave, convex, hemispherical, pyramidal, conical and cylindrical.

24. The method of claim 1 wherein the power to the electrode terminal is controlled based on the electrical impedance between the electrode terminal and the return electrode.

25. The method of claim 1 wherein temperature at the target site is measured by a temperature sensor adjacent to the electrode terminal such that power delivery to the electrode terminal is limited if the measured temperature exceeds a threshold value.

26. The method of claim 25 wherein the temperature sensor is integral with the electrode terminal.