Electrosurgical device

Abstract

A surgical instrument is configured to reduce conductivity between an RF electrosurgical portion and a cutting portion. This reduces improves the efficiency and consistency of the generated RF field, with higher current densities nearest the target tissue, improving the performance of the RF electrosurgical instrument. The conductivity may be reduced using a layer of insulating material, a projecting insulating portion or a cutting portion constructed from an insulating material. Further, by providing a lubricous insulating layer shedding may be reduced, increasing the usable life of the cutting portion.

1 . An electrosurgical end effector, comprising:
 a rotary shaver arrangement, having a rotatable tubular element with a cutting portion having a cutting blade formed therein that when in use is able to cut tissue located in an operative cutting direction;   an active electrode;   a second tubular element concentrically arranged around the rotatable tubular element, the second tubular element having a cutting window formed in a wall thereof such that the cutting blade of the rotatable tubular element is located within the window, wherein the outside surface of the second tubular element is a return electrode; and   an insulating portion projecting distally from the distal end of the rotatable tubular element, arranged so as to reduce conductivity between the second tubular element and the first cutting portion.   
     
     
         2 . The electrosurgical end effector according to  claim 1 , wherein the insulating portion is in contact with the inner distal end of the second tubular element, acting as the bearing surface between the rotatable tubular element and the second tubular element. 
     
     
         3 . The electrosurgical end effector according to  claim 1 , wherein the insulating portion is one of:
 a ceramic; or   a polymer.   
     
     
         4 . The electrosurgical end effector according to  claim 1 , wherein the insulating portion is overmoulded or deposited on the distal end of the first cutting portion. 
     
     
         5 . The electrosurgical end effector according to  claim 1 , wherein the insulating portion comprises a push-fit insert that is inserted into a suitable receiving geometry, wherein the suitable receiving geometry is located on one of:
 the distal end of the first cutting portion; or   the inner distal hemisphere of the second tubular element.   
     
     
         6 . The electrosurgical end effector according to  claim 1 , wherein the material of the insulating portion is lubricous. 
     
     
         7 . An electrosurgical instrument comprising an electrosurgical end effector according to  claim 1 , the electrosurgical instrument comprising:
 a hand-piece;   one or more user operable buttons on the handpiece that control the instrument; and   an operative shaft, having RF electrical connections, and drive componentry for the end effector, the rotary shaver arrangement being operably connected to the drive componentry to drive the rotary shaver to operate in use, and the active electrode being connected to the RF electrical connections.   
     
     
         8 . An electrosurgical system comprising an electrosurgical instrument according to  claim 7 , and further comprising:
 an RF electrosurgical generator; and   a suction source;   the arrangement being such that in use the RF electrosurgical generator supplies an RF coagulation or ablation signal via the RF electrical connections to the active electrode, to permit tissue coagulation or ablation.   
     
     
         9 . An electrosurgical end effector, comprising:
 a rotary shaver arrangement, having a rotatable tubular element with a cutting portion having a cutting blade formed therein that when in use is able to cut tissue located in an operative cutting direction;   an active electrode;   a second tubular element concentrically arranged around the rotatable tubular element, the second tubular element having a cutting window formed in a wall thereof such that the cutting blade of the rotatable tubular element is located within the window, wherein the outside surface of the second tubular element is a return electrode; and   an insulating layer arranged so as to reduce the conductivity between the second tubular element and the first cutting portion.   
     
     
         10 . The electrosurgical end effector according to  claim 9 , wherein the insulating layer is one of:
 a surface treatment, such as an anodized layer;   a polymer layer; or   a diamond like carbon, DLC, layer.   
     
     
         11 . The electrosurgical end effector according to  claim 9 , wherein the material of the insulating layer is lubricous. 
     
     
         12 . The electrosurgical end effector according to  claim 9 , wherein the insulating layer is a layer covering one or more of:
 the rotatable tubular element;   the distal end of the rotatable tubular element;   the internal radius of the second tubular element; and/or   the external radius of the second tubular element.   
     
     
         13 . The electrosurgical end effector according to  claim 9  wherein the rotatable tubular element is constructed of a non-conductive material, such as ceramic, wherein the surface of the non-conductive material acts as the insulating layer. 
     
     
         14 . An electrosurgical instrument comprising an electrosurgical end effector according to  claim 9 , and further comprising:
 a hand-piece;   one or more user operable buttons on the handpiece that control the instrument; and   an operative shaft, having RF electrical connections, and drive componentry for an end effector, the rotary shaver arrangement being operably connected to the drive componentry to drive the rotary shaver to operate in use, and the active electrode being connected to the RF electrical connections.   
     
     
         15 . An electrosurgical system comprising an electrosurgical end effector according to  claim 9 , and further comprising:
 an RF electrosurgical generator; and   a suction source;   the arrangement being such that in use the RF electrosurgical generator supplies an RF coagulation or ablation signal via the RF electrical connections to the active electrode, to permit tissue coagulation or ablation.   
     
     
         16 . An electrosurgical system comprising an electrosurgical instrument according to  claim 14 , and further comprising:
 an RF electrosurgical generator; and   a suction source;   the arrangement being such that in use the RF electrosurgical generator supplies an RF coagulation or ablation signal via the RF electrical connections to the active electrode, to permit tissue coagulation or ablation.