Method for epidermal tissue ablation

• US 6,773,431 B2
• Filed: 02/22/2001
• Issued: 08/10/2004
• Est. Priority Date: 06/07/1995
• 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
• Application Number:
  US09/791,504
• Publication Number:
  US 20010049522A1
• Time in Patent Office: 1,265 Days
• Field of Search: 606/32, 606/41, 606/99, 606/105, 606/113, 604/114, 128/898
• US Class Current: 606/32
• 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 2017/00247 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 2018/00761 : 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 2018/1253 : 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 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

A system and method for surface tissue ablation on the patient'"'"'s outer skin, such as the epidermis or the underlying dermis. An electrosurgical probe 130) comprises a shaft 132) having an array of active electrodes 136) on its distal tip and a connector 134) at its proximal end for coupling the electrode array to a high frequency power supply. An electrically conducting liquid is directed along a fluid flow path 142) past a return electrode surface 138) to the target site to provide a current flow path between the target site and the return electrode. High frequency voltage is then applied to the active and return electrodes so that an electric current flows from the active electrode, through a layer of vapor formed at the tip of the electrode, and to the return electrode through the current flow path provided by the electrically conducting liquid. The high frequency voltage will preferably be sufficient to establish high electric field densities between the active electrode array and the epidermal tissue to thereby induce molecular breakdown or disintegration of several cell layers of the tissue.

Claims

1. A method for dermatological treatment of a patient body surface comprising:

positioning a probe having an active electrode surface in close proximity to a target site on the epidermis of the patient;

directing an electrically conducting liquid along a fluid flow path past a return electrode surface to the target site to provide a current flow path between the target site and the return electrode; and

applying high frequency voltage between the active electrode surface and the return electrode surface to impart sufficient energy into the target site to ablate several cells layers of the epidermis without causing substantial tissue necrosis beyond said several cell layers.

2. The method of claim 1 wherein the applying step comprises:

vaporizing the electrically conducting liquid in a thin layer over at least a portion of the active electrode surface; and

inducing the discharge of energy from the vapor layer.

3. The method of claim 2 wherein the energy is in the form of ultraviolet energy.

4. The method of claim 2 wherein the energy is in the form of energetic electrons.

5. The method of claim 1 wherein the active electrode surface comprises an electrode array including a plurality of isolated electrode terminals.

6. The method of claim 5 wherein the electrode terminals are substantially flush with an electrically insulating matrix on a distal tip of the probe.

7. The method of claim 5 wherein the electrode terminals are proximally recessed a distance of 0.0 to 0.005 inches from an electrically insulating matrix on a distal tip of the probe.

8. The method of claim 5 wherein the electrode terminals distally extend a distance of 0.0 to 0.005 inches from an electrically insulating matrix on a distal tip of the probe.

9. The method of claim 5 further comprising axially reciprocating the electrode terminals to adjust a distance between a distal surface of the electrode terminals and an electrically insulating matrix on a distal tip of the probe.

10. The method of claim 5 further comprising translating the electrode array transversely across a layer of epidermal tissue.

11. The method of claim 10 wherein a distal end of the probe is beveled to facilitate translation of the electrode array.

12. The method of claim 5 further comprising generating a high electric field intensity at a distal portion of the electrode array.

13. The method of claim 12 wherein the electric field intensity is sufficient to cause molecular disintegration of tissue structure on the target site.

14. The method of claim 1 wherein the high frequency voltage is in the range from 600 to 1400 volts peak to peak.

15. The method of claim 1 wherein the depth of necrosis is 10 to 200 microns.