Planar ablation probe and method for electrosurgical cutting and ablation

• US 5,902,272 A
• Filed: 07/16/1996
• Issued: 05/11/1999
• Est. Priority Date: 01/07/1992
• Status: Expired due to Term

• Current Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Original Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Inventors: Eggers, Philip E., Thapliyal, Hira V.
• Primary Examiner(s): Yasko, John D.
• Assistant Examiner(s): MENDEZ, MANUEL A
• Application Number:
  US08/690,159
• Time in Patent Office: 1,029 Days
• Field of Search: 604/22, 604/113, 604/114, 604/41, 606/27-32, 606/35, 606/38, 606/41
• US Class Current: 604/114
• 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 18/14 Probes or electrodes 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 2017/00247 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 2018/00434 : Neural system
• 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 2018/00642 : 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 2018/00761 : 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 2018/1213 : creating an arc
• CPC Class Codes: A61B 2018/124 : switching the output to different electrodes, e.g. sequentially
• 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 2018/1467 : 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 2018/1497 : Electrodes covering only part of the probe circumference
• 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 2218/002 : Irrigation
• CPC Class Codes: A61B 2218/007 : Aspiration
• CPC Class Codes: A61F 2/2493 : Transmyocardial revascularisation [TMR] devices
• 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 ablation probe is provided having a shaft with a proximal end portion and a tongue-shaped distal end portion sized to fit within confined (e.g., narrow) spaces within the patient'"'"'s body, such as the spaces around the articular cartilage between the femur and tibia and the spaces between adjacent vertebrae in the patient'"'"'s spine. The probe includes at least one active electrode integral with or coupled to the tongue-shaped distal end portion and a connector on the proximal end portion for coupling the active electrode to an electrosurgical generator. The tongue-shaped distal end portion is substantially planar, and it offers a low profile, to allow access to confined spaces without risking iatrogenic injury to surrounding tissue, such as articular cartilage.

Claims

1. An electrosurgical system for use with a high frequency power supply, the system comprising:

an electrosurgical probe comprising a shaft having inner and outer surfaces, a proximal end portion and a distal end portion, one or more active electrodes each having an elongate body disposed at the distal end portion of the shaft, and a connector near the proximal end of the shaft for electrically coupling the active electrodes to the electrosurgical power supply, the distal end portion having a substantially narrow body sized to fit within a confined space within the patient'"'"'s body;

a return electrode on the shaft proximally spaced from the distal end portion to generate a current flow path between the active electrodes and the return electrode; and

an electrically conducting fluid supply, the shaft defining a fluid path coupled to the electrically conducting fluid supply and in electrical contact with and between the return electrode and the active electrodes for generating a current flow path between the return electrode and active electrodes.

2. The system of claim 1 wherein the active electrodes each have an active portion with a surface geometry configured to promote substantially high electric field intensities and associated electric field intensities between the active portion and the target site when a high frequency voltage is applied to the active electrodes.

3. The system of claim 1 wherein the distal end portion of the shaft has an active side and a substantially planar non-active side opposing the active side, the active electrodes being disposed on the active side and being insulated from the non-active side.

4. The system of claim 1 wherein the distal end portion has a thickness from the active side to the non-active side of less than 2 mm.

5. A method for applying electrical energy to a target site within a confined space in a patient'"'"'s body, the method comprising:

introducing one or more active electrodes into a narrow, confined space within the patient'"'"'s body to at least close proximity with the target site in the presence of electrically conductive fluid, the space having a minimum dimension of about 0.5 to 5.0 mm; and

applying a high frequency voltage difference between the active electrodes and a return electrode such that an electrical current flows from the active electrodes, through the body structure in the region of the target site, and to the return electrode.

6. The method of claim 5 wherein the active electrodes are introduced into spaces between articular cartilage and the meniscus between the tibia and the femur to access meniscal tissue at the meniscus/tibial plateau interface.

7. The method of claim 5 wherein the active electrodes are introduced into spaces between intervertebral disks in the spine.

8. The method of claim 5 wherein the active electrodes are disposed on an active side of a distal end portion of a shaft, the method further comprising insulating the active electrodes from an opposing non-active side of the distal end portion of the shaft.

9. The method of claim 8 further comprising supporting the active electrodes with a tongue-shaped support member on the distal end portion of the shaft and insulating the active electrodes from the support member.

10. The method of claim 5 further comprising positioning the return electrode within the electrically conducting fluid to generate a current flow path between the active electrodes and the return electrode.

11. The method of claim 10 wherein the return electrode is on the shaft proximal to the active electrodes.

12. The method of claim 5 wherein the active electrodes comprise an array of independent, isolated electrodes, the method further comprising independently controlling current flow from at least two of the electrodes based on impedance between the electrode and the return electrode.

13. The method of claim 5 further comprising promoting substantially high, localized electric field intensities between an active portion of the active electrodes and the tissue.

14. The method of claim 13 wherein the active portion of each active electrode has one or more edges for promoting localized electric fields around the edges.

15. The method of claim 14 wherein the active portion of each active electrode defines a semi-circular transverse cross-sectional shape with first and second ends and an inner slot therebetween.

16. The method of claim 10 further comprising vaporizing the electrically conducting fluid in a thin layer over at least a portion of the active electrode and inducing the discharge of energy from the vapor layer.

17. The method of claim 16 further comprising imparting sufficient energy into the target site to ablate several cell layers of the body structure without causing substantial tissue necrosis beyond the several cell layers.