Electrosurgical electrodes

Abstract

An electrode assembly is provided. The electrode assembly includes a proximal end that is adapted to connect to an electrosurgical instrument including a housing defining a longitudinal axis therethrough and an electrosurgical energy source. A distal end includes a cutting electrode having a loop configuration configured to cut tissue. The distal end includes a return electrode operably disposed adjacent the cutting electrode. A dielectric shield is operably disposed between the cutting electrode and return electrode. The dielectric shield extending distally past the cutting electrode to hinder current flow to the return electrode when the dielectric shield, cutting electrode and return electrode are submersed in a conductive solution and the cutting electrode is energized, thereby concentrating current density at the cutting electrode.

What is claimed is: 
     
         1 . An electrode assembly, comprising:
 a proximal end adapted to connect to an electrosurgical instrument including a housing defining a longitudinal axis therethrough and an electrosurgical energy source;   a distal end including a cutting electrode having a loop configuration configured to cut tissue, the distal end including a return electrode operably disposed adjacent the cutting electrode; and   a dielectric shield operably disposed between the cutting electrode and return electrode, the dielectric shield extending distally past the cutting electrode to hinder current flow to the return electrode when the dielectric shield, cutting electrode and return electrode are submersed in a conductive solution and the cutting electrode is energized, thereby concentrating current density at the cutting electrode.   
     
     
         2 . An electrode assembly according to  claim 1 , wherein the dielectric shield is disposed parallel to the longitudinal axis defined by the housing, and above the cutting electrode. 
     
     
         3 . An electrode assembly according to  claim 1 , wherein the dielectric shield includes a generally arcuate configuration and extends laterally across the electrode assembly. 
     
     
         4 . An electrode assembly according to  claim 1 , wherein the dielectric shield is formed from material selected from the group consisting of flouropolymer, polyimide, polyamide, polyaryl sulfone and silicone plastic. 
     
     
         5 . An electrode assembly according to  claim 1 , wherein a thickness of the dielectric shield ranges from about 0.005 inches to 0.100 inches. 
     
     
         6 . An electrode assembly according to  claim 1 , wherein the cutting electrode is a wire made from metal selected from the group consisting of tungsten, tungsten alloys and stainless steel. 
     
     
         7 . An electrode assembly according to  claim 6 , wherein a cross-section diameter of the wire ranges from about 0.25 mm to about 4 mm. 
     
     
         8 . An electrode assembly according to  claim 1 , wherein the loop configuration of the cutting electrode includes a diameter that ranges from about 3 mm to about 10 mm. 
     
     
         9 . An electrode assembly according to  claim 1 , wherein a cross section of the cutting electrode includes a shape selected from the group consisting of circular, hemicircular, square, rectangular, triangular, polygonal and combinations thereof. 
     
     
         10 . An electrosurgical instrument, comprising:
 an elongated housing having a lumen defining a longitudinal axis therethrough, the elongated housing having distal and proximal ends, the proximal end adapted to connect to an electrosurgical energy source;   an electrode assembly comprising:
 a proximal end adapted to connect to the distal end of the elongated housing; 
 a distal end including a cutting electrode having a loop configuration configured to cut tissue, the distal end including a return electrode operably disposed adjacent the cutting electrode; and 
 a dielectric shield operably disposed between the cutting electrode and return electrode, the dielectric shield extending distally past the cutting electrode to hinder current flow to the return electrode when the dielectric shield, cutting electrode and return electrode are submersed in a conductive solution and the cutting electrode is energized, thereby concentrating current density at the cutting electrode. 
   
     
     
         11 . An electrode assembly, comprising:
 a proximal end adapted to connect to an electrosurgical instrument including a housing defining a longitudinal axis therethrough and an electrosurgical energy source;   a distal end including a cutting electrode having a loop configuration configured to cut tissue, the distal end including a return electrode operably disposed adjacent the cutting electrode; and   an insulative material operably disposed between the cutting electrode and return electrode to hinder current flow to the return electrode when the insulative material, cutting electrode and return electrode are submersed in a conductive solution and the cutting electrode is energized, thereby concentrating current density at the cutting electrode.   
     
     
         12 . An electrode assembly according to  claim 11 , wherein the insulative material is disposed parallel to the longitudinal axis defined by the housing, and above the cutting electrode. 
     
     
         13 . An electrode assembly according to  claim 11 , wherein a proximal end of the cutting electrode includes a pair of curved sections. 
     
     
         14 . An electrode assembly according to  claim 13 , wherein the insulative material is operably disposed along the pair of curved sections of the cutting electrode. 
     
     
         15 . An electrode assembly according to  claim 11 , wherein the insulative material is selected from the group consisting of flouropolymer, polyimide, polyamide, polyaryl sulfone, silicone plastic and polytetrafluoroethylene.