Ablation apparatus having reduced nerve stimulation and related methods

• US 7,862,560 B2
• Filed: 03/23/2007
• Issued: 01/04/2011
• Est. Priority Date: 03/23/2007
• Status: Expired due to Fees

• Current Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Original Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Inventors: Marion, Duane W.
• Primary Examiner(s): Cohen; Lee S
• Assistant Examiner(s): DELLA, JAYMI E
• Application Number:
  US11/690,449
• Publication Number:
  US 20080234671A1
• Time in Patent Office: 1,383 Days
• Field of Search: 606/32, 606/37, 606/39, 606/40, 606 51- 52
• US Class Current: 606/34
• CPC Class Codes: A61B 18/1233 with circuits for assuring patient safety
• 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 2018/00083 low, i.e. electrically insulating
• CPC Class Codes: A61B 2218/002 Irrigation

Abstract

Apparatus and methods for reducing nerve stimulation in electrosurgical instruments utilizing electrically isolated pairs of electrodes are disclosed. At least two pairs of electrodes may be configured to create at least two opposing currents which effectively cancel one another such that a net current flow is inhibited from developing within surrounding tissue structures to mitigate or eliminate undesired electrical stimulation of the tissue.

Claims

1. An electrosurgical instrument electrically coupled to a primary input circuit of a power supply transformer and configured to inhibit electrical stimulation of surrounding tissue structures, comprising:

a first electrode pair electrically connected to a first output coil of the transformer, the primary input circuit inducing a first current in the first output coil and thereby a first voltage waveform between the first electrode pair; and

a second electrode pair electrically isolated from the first electrode pair and disposed adjacent to the first electrode pair,

wherein the second electrode pair is electrically connected to a second output coil of the transformer, wherein the second output coil is electrically isolated from the first output coil and the primary input circuit induces a second current in the second electrode pair and thereby a second voltage waveform between the second electrode pair which is out of phase with the first voltage waveform.

2. The instrument of claim 1 further comprising an elongated shaft upon which the first and second electrode pairs are positioned adjacent to one another.

3. The instrument of claim 1 wherein the first electrode pair comprises at least one active electrode and at least one return electrode.

4. The instrument of claim 1 wherein the second electrode pair comprises at least one active electrode and at least one return electrode.

5. The instrument of claim 1 wherein an amplitude of the first voltage waveform is equal to an amplitude of the second voltage waveform.

6. The instrument of claim 1 wherein the first electrode pair has a current flowing from a first active electrode to a first return electrode.

7. The instrument of claim 1 wherein an amplitude of the first current is equal to an amplitude of the second current.

8. The instrument of claim 1 wherein the first and second voltage waveforms are 180°

out-of-phase compared to one another.

17. The instrument of claim 1, wherein the first current travels in the opposite direction to the second current.

9. A method of reducing or eliminating a net current in tissue structures adjacent to an electrosurgical instrument, comprising:

positioning an electrosurgical instrument in proximity to a tissue region to be treated, the electrosurgical instrument having at least a first electrode pair and a second electrode pair adjacent to the first electrode pair, wherein each electrode pair is powered by a separate, electrically isolated output circuit of a power supply transformer;

inducing a first current flowing through the first electrode pair; and

inducing a second current flowing through the second electrode pair such that an output of the first current is out-of-phase compared to an output of the second current.

10. The method of claim 9 wherein positioning comprises advancing the electrosurgical instrument within a body space of a patient.

11. The method of claim 10 wherein advancing comprises placing the electrosurgical instrument within a joint space of the patient.

12. The method of claim 9, wherein the tissue region comprises one tissue selected from the group consisting of tonsils, turbinates, disks, vertebral bodies, cartilage, meniscus, fascia, synovial tissue, tendon, and capsular tissue.

13. The method of claim 9, wherein inducing the first current comprises inducing the first current via a power supply common to the first and second electrode pairs.

14. The method of claim 9, wherein inducing the second current comprises inducing the second current to be of equal amplitude compared to the first current.

15. The method of claim 9, wherein the output of the first current is at least 180°

out-of-phase compared to the output of the second current.

16. The method of claim 9 further comprising treating the tissue region via the first or second electrode pairs.