Patent ID: 8177784

Claim:
An electrosurgical instrument comprising: a linear elongate conductive shaft having a longitudinal axis, a proximal end configured for connection to an electrosurgical power source and a distal end having a layered electrode assembly mounted at an angle thereto by means of a pair of parallel conductive members that facilitate the attachment of said electrosurgical instrument to a resectoscope, said conductive members having respective proximal ends affixed to the distal end of the shaft and respective distal ends affixed to said layered electrode assembly; wherein said layered electrode assembly has an upper surface and a lower surface and a vertical axis that extends between said surfaces and is transverse to said longitudinal axis, said assembly comprising (a) a planar insulator formed from a nonconductive dielectric material sandwiched between (b) an active electrode formed from an electrically conductive material and electrically connected to said conductive shaft and (c) a floating electrode formed from an electrically conductive material that is not directly connected to an electrosurgical power source, wherein the vertical axis of the electrode assembly forms an acute angle with a longitudinal axis of elongate shaft, further wherein: (i) said active electrode has opposed first and second surfaces, wherein the first surface is a proximal-facing active surface comprised of a continuous or discontinuous array of raised and recessed portions that create regions of high current density for high efficiency vaporization of tissue and the second surface is a distal-facing shielded surface, further wherein the distal ends of said conductive members are directly affixed to said first proximal-facing active surface of said active electrode; (ii) said insulator has opposed first and second surfaces, wherein the first surface is a proximal-facing planar surface and the second surface is a distal-facing planar surface, wherein the first proximal-facing surface of the insulator is adhered to and electrically shields the distal-facing surface of the active electrode; and (iii) said floating electrode has opposed first and second surfaces, wherein the first surface is a proximal-facing planar surface and the second surface is a distal-facing surface, wherein the first proximal-facing surface of the floating electrode is adhered to the second distal-facing surface of the insulator.