SYSTEMS AND METHODS SYSTEMS RELATED TO ELECTROSURGICAL WANDS WITH SCREEN ELECTRODES

• US 20150245862A1
• Filed: 02/28/2014
• Published: 09/03/2015
• Est. Priority Date: 02/28/2014
• Status: Active Grant

• Current Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Original Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Inventors: Goode, Johnson E., Tetzlaff, Philip M., Woloszko, Jean, Bieberich, Mark
• Granted Patent: US 9,526,556 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 18/042 using additional gas becoming plasma
• CPC Class Codes: A61B 18/14 Probes or electrodes therefor
• 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 2018/00577 Ablation
• CPC Class Codes: A61B 2018/1405 Electrodes having a specific shape
• CPC Class Codes: A61B 2018/162 located on the probe body
• CPC Class Codes: A61B 2218/007 Aspiration

Abstract

An electrosurgical wand for treating tissue at a target site within or on a patient'"'"'s body is described, having an elongate shaft with a handle and a distal end portion. The distal end portion has an active electrode, an insulative spacer body and a return electrode; the active electrode supported by the insulative spacer body and spaced away from the return electrode. The active electrode has both lateral and medial edge surfaces. The insulative spacer body has an aspiration cavity fluidly connected with an aspiration lumen, and at least one tapered aperture extending beyond at least one of the electrode medial edge surfaces and directed to the aspiration cavity.

Claims

1. An electrosurgical wand for treating tissue at a target site within or on a patient'"'"'s body comprising:

an elongate shaft characterized by a handle and a distal end portion, the distal end portion comprising an active electrode, an insulative spacer body and a return electrode, wherein the active electrode is supported on the insulative spacer body and is spaced away from the return electrode;

wherein the active electrode defines lateral and medial edge surfaces;

wherein the insulative spacer body defines an aspiration cavity fluidly connected with an aspiration lumen, the insulative spacer body further defined by at least one tapered aperture extending beyond at least one of the medial edge surfaces and directed to the aspiration cavity.

2. The electrosurgical wand of claim 1 wherein at least one active electrode lateral edge surface is free of any asperities and spaced away from the at least one aperture.

3. The electrosurgical wand of claim 2 wherein the active electrode further comprises an electrode aperture in fluid communication with the aspiration cavity and spaced away from both the lateral edge surface and the at least one tapered aperture.

4. The electrosurgical wand of claim 1 further comprising at least two tapered apertures extending beyond the medial edge surfaces and directed to the aspiration cavity and wherein the two tapered apertures are disposed on opposing medial edge surfaces.

5. The electrosurgical wand of claim 1 wherein the medial edge surface of the screen electrode further comprises at least one internal cusp.

6. The electrosurgical wand of claim 1 wherein the active electrode defines a central aspiration aperture aligned with the aspiration cavity.

7. The electrosurgical wand of claim 1 further comprising at least one securing wire of conductive material, electrically coupled to and mechanically secured to a tissue contacting surface of the active electrode and wherein the at least one securing wire is disposed along a path defined by at least one active electrode wire aperture, at least one spacer body wire conduit and the elongate shaft and wherein the at least one securing wire is in electrical communication with a high frequency energy source.

8. The electrosurgical wand of claim 1 wherein the aspiration cavity is characterized by an elongate funnel shape, tapering to a lumen of circular cross section within the spacer body.

9. The electrosurgical wand of claim 8 wherein the aspiration cavity tapers so as to define a maximum gap within the aspiration cavity, the gap operable to trap any larger tissue fragments within the aspiration cavity so that the tissue fragment are further ablated by a portion of the active screen electrode before allowing the fragments to pass into the lumen of circular cross section.

10. The electrosurgical wand of claim 4 wherein one of the tapered apertures extends a first distance beyond a first medial edge surface and a second tapered aperture extends a second distance beyond a second medial edge surface of the active electrode and wherein the first distance is smaller than the second distance.

11. The electrosurgical wand of claim 4 wherein a first medial edge surface of the active electrode has at least one internal cusp with a first depth and a second medial edge surface of the active electrode has at least one internal cusp with a second depth and wherein the first cusp depth is significantly smaller than the second cusp depth.

12. The electrosurgical wand of claim 5 wherein the at least one internal cusp is defined by an intersection between two adjacent curved portions, the intersection characterized by a minimal transition between the two adjacent curved portions.

13. An electrosurgical wand for treating tissue at a surgical site comprising:

an elongate housing that defines a handle end and a tissue contacting surface at a distal end;

an active screen electrode defining a portion of the tissue contacting surface, the active electrode disposed on an insulating spacer, said insulating spacer also defining a portion of the tissue contacting surface;

wherein the screen electrode comprises at least one lateral edge surface free of any surface asperities, and a distal edge surface characterized by at least one surface asperity and a proximal edge surface, characterized by at least one surface asperity;

wherein the tissue contacting surface further comprises a first aspiration aperture spaced at discrete location away from the lateral edge surface, the first aspiration aperture in fluid communication with an aspiration lumen disposed within the wand and operable to remove debris from the surgical site, and wherein the first aspiration aperture has a perimeter defined by a portion of an insulating spacer cavity and a portion of either the electrode distal edge surface or the electrode proximal edge surface.

14. The electrosurgical wand of claim 13 wherein the tissue contacting surface further comprises a second aspiration aperture spaced away from the lateral edge surface and the first aspiration aperture, the second aspiration aperture in fluid communication with an aspiration lumen disposed within the wand and operable to remove debris from the surgical site, and wherein the second aspiration aperture has a perimeter defined by a portion of the insulating spacer cavity and a portion of either the electrode distal end surface or the electrode proximal edge surface.

15. The electrosurgical wand of claim 14 further comprising a third aspiration aperture defined completely by the active electrode and wherein the first, second and third aspiration apertures are coplanar on a plane that is medially spaced from the lateral edge surface.

16. The electrosurgical wand of claim 15 wherein the active electrode has two opposing lateral edge surfaces and the aspiration apertures are disposed on a plane characterized as equidistant between the two opposing lateral edge surfaces.

17. The electrosurgical wand of claim 13 wherein the distal and proximal edge surface asperities are internal cusps.

18. A method of treating a target tissue using an electrosurgical wand comprising:

placing a distal end portion of the wand proximate a target tissue, the distal end portion comprising a substantially flat active screen electrode and an insulative spacer, the screen electrode supported by the spacer;

applying a high frequency voltage between the active electrode and a return electrode spaced away from the active electrode, the high frequency voltage sufficient to generate a vapor layer or plasma proximate a tissue contacting surface of the active electrode;

orienting the distal end portion so that a lateral edge surface of the active electrode is proximate a target tissue and treating the target tissue; and

aspirating tissue fragments and gas bubbles through at least one aspiration aperture disposed in a discrete location spaced away from the lateral edge surface so as to not disrupt the vapor layer or plasma proximate the active electrode lateral edge surface, wherein the at least one aspiration aperture is defined by a portion of the active screen electrode and a portion of a spacer aspiration cavity.

19. The method of claim 18 wherein the at least one aspiration aperture comprises at least three aspiration apertures and wherein the step of aspirating further comprises aspirating the tissue fragments and gas bubbles approximately equally through the at least three aspiration apertures, wherein the at least three apertures are coplanar on a plane spaced away from the lateral edge surface and the at least three apertures are approximately evenly spaced and of differing sizes so as to uniformly aspirate along a length of the lateral edge surface.