Systems and methods systems related to electrosurgical wands with screen electrodes

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.

What is claimed is: 
     
         1 . An electrosurgical wand for treating a target tissue within or on a patient's body comprising:
 an elongate shaft having a handle end 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 insulative spacer defines a side surface and wherein the active electrode defines a peripheral edge surface;   wherein the insulative spacer side surface is configured to initially engage tissue and direct the peripheral edge surface towards the target tissue.   
     
     
         2 . The electrosurgical wand of  claim 1  wherein the insulative spacer body defines a planar end surface having a beveled edge and wherein the active electrode abuts the planar end surface, and the active electrode edge surface is parallel to the beveled edge. 
     
     
         3 . The electrosurgical wand of  claim 1  wherein the active electrode edge surface is free of any asperities. 
     
     
         4 . The electrosurgical wand of  claim 1  wherein the active electrode further comprises an aspiration aperture spaced away from the active electrode peripheral edge surface. 
     
     
         5 . The electrosurgical wand of  claim 1  wherein the insulative spacer side surface is configured to initially engage tissue and also direct the electrode peripheral edge surface towards the target tissue, as the distal end portion rolls. 
     
     
         6 . The electrosurgical wand of  claim 1  wherein the insulative spacer side surface is configured to initially engage tissue and direct the electrode peripheral edge surface towards the target tissue to an orientation such that bubbles formed at the electrode peripheral edge surface will rise towards an aspiration aperture spaced away from the electrode peripheral edge surface. 
     
     
         7 . The electrosurgical wand of  claim 1  wherein the insulative spacer has a distal facing planar surface for abutting the active electrode, the distal facing planar surface oriented along a plane that is angled relative to a wand longitudinal axis. 
     
     
         8 . The electrosurgical wand of  claim 7  wherein the distal facing planar surface defines a non-circular cross-sectional shape. 
     
     
         9 . A method of treating a target tissue using an electrosurgical wand in a targeted orientation relative to the target tissue comprising:
 placing a spacer lateral side surface of a distal end of the wand proximate the target tissue, the distal end comprising an active 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 proximate a tissue contacting surface of the active screen electrode; and.   moving the wand distal end to place a beveled edge of the spacer closer to the target tissue and then continuing to move the wand distal end to place an edge surface of the active electrode adjacent the target tissue in the targeted orientation.   
     
     
         10 . The method of  claim 9  wherein the high frequency voltage is applied while moving the wand distal end portion. 
     
     
         11 . The method of  claim 10  further comprising moving the wand distal end until the vapor layer proximate the edge surface of the active electrode is observed and thereby defining the targeted orientation. 
     
     
         12 . The method of  claim 9  wherein moving comprises rolling the wand distal end. 
     
     
         13 . The method of  claim 9  further comprising aspirating gas bubbles through at least one aspiration aperture disposed in a discrete location spaced away from the active electrode edge surface. 
     
     
         14 . The method of  claim 13  wherein targeted orientation places the at least one aspiration aperture at a location spaced away from the vapor layer, configured so as to minimally disrupt the vapor layer proximate the active electrode edge surface. 
     
     
         15 . A method of placing a lateral edge surface of an active electrode on an distal end of the electrosurgical wand sufficiently close to treat a target tissue:
 first engaging the target tissue with a spacer lateral side; and then moving a beveled edge towards the target tissue and thereby placing the lateral edge surface of an active electrode sufficiently close to treat the target tissue.   
     
     
         16 . The method of  claim 15  further comprising applying a high frequency voltage while first engaging and then moving. 
     
     
         17 . The method of  claim 16  further comprising moving the wand distal end until the vapor layer proximate the lateral edge surface is observed. 
     
     
         18 . The method of  claim 15  wherein moving comprises rolling the wand distal end. 
     
     
         19 . The method of  claim 15  further comprising aspirating gas bubbles through at least one aspiration aperture disposed in a discrete location spaced away from the active electrode lateral edge surface. 
     
     
         20 . The method of  claim 19  wherein moving the wand distal end portion places the at least one aspiration aperture at a location spaced away from the target tissue.