Systems and methods for screen electrode securement

Abstract

Systems and methods for securing a screen-type active electrode to the distal tip of an electrosurgical device used for selectively applying electrical energy to a target location within or on a patient's body. A securing electrode is disposed through the screen electrode and mechanically joined to an insulative support body while also creating an electrical connection and mechanical enagement with the screen electrode. The electrosurgical device and related methods are provided for resecting, cutting, partially ablating, aspirating or otherwise removing tissue from a target site, and ablating the tissue in situ. The present methods and systems are particularly useful for removing tissue within joints, e.g., synovial tissue, meniscus, articular cartilage and the like.

What is claimed is: 
     
         1 . A method for securing a substantially flat active screen electrode to a distal end of an electrosurgical instrument comprising:
 disposing the screen electrode upon an electrically insulating support member;   extending an end portion of a securing electrode through the screen electrode and the support member, wherein the securing electrode and the screen electrode are mechanically and electrically connected;   fixedly engaging the end portion of the securing electrode with a portion of the electrically insulating support member, the securing electrode mechanically securing the screen electrode to the support member; and   coupling the securing electrode to an electrical connector, wherein the electrical connector is connected with a high frequency power supply.   
     
     
         2 . The method of  claim 1  wherein the end portion of the securing electrode comprises a tab. 
     
     
         3 . The method of  claim 1  wherein the portion of the electrically insulating support member comprises an axial slot. 
     
     
         4 . The method of  claim 1  wherein the securing electrode has a head that engages a superior surface of the screen electrode. 
     
     
         5 . The method of  claim 1  wherein the screen electrode and the securing electrode are prevented from moving axially and laterally with respect a shaft of the instrument. 
     
     
         6 . The method of  claim 1  wherein the end portion has a threaded surface that threadingly engages a complimentary threaded surface on the support member. 
     
     
         7 . The method of  claim 1  further comprising securing the end portion to the support member with an epoxy. 
     
     
         8 . A method for treating a target tissue whereby a portion of the target tissue is removed, comprising the steps of:
 advancing a probe comprising a proximal end, a shaft, a distal end portion, a substantially flat active screen electrode, and an insulative support member, the screen electrode supported by the support member and secured on the distal end portion of the probe such that the screen electrode is positioned in close proximity to the target tissue, and wherein the screen electrode is electrically coupled and mechanically secured to the support member by first and second bilateral securing electrodes such that an active electrode assembly is formed, wherein the first and second bilateral securing electrodes have end portions extending through and engaging the support member, said probe further comprising at least one electrical connector extending through the shaft and terminating proximal to the end portions of the first and second bilateral securing electrodes;   delivering an electrically conductive fluid to the target tissue;   applying a high frequency voltage between the active electrode assembly and a return electrode sufficient to generate a plasma between the first and second bilateral securing electrodes and the screen electrode; and   whereby the plasma ablates target tissue at a target site.   
     
     
         9 . The method of  claim 8  further comprising applying suction to an aspiration lumen disposed within the probe, the aspiration lumen being in fluid communication with openings in the screen electrode. 
     
     
         10 . The method of  claim 8  wherein the end portions comprise tabs. 
     
     
         11 . The method of  claim 8  wherein the first and second bilateral securing electrodes are symmetrically disposed on the screen electrode. 
     
     
         12 . The method of  claim 8  wherein the plasma between the first and second bilateral securing electrodes and the screen electrode comprises and three dimensional plasma chamber.