Patent ID: 8323279

Claim:
A system for treating tissue, comprising: an electrosurgical instrument having a shaft with a proximal end and a distal end portion; an electrode assembly positioned on the distal end portion of the shaft comprising at least one active electrode and at least one return electrode axially spaced from the at least one active electrode; a fluid delivery element for delivering electrically conductive fluid to the active electrode comprising an inner lumen extending through a portion of the shaft, and first and second ports extending radially through the shaft in fluid communication with the inner lumen; and a sheath assembly disposed adjacently to the fluid delivery element and comprising at least one radial seal to sealingly engage the shaft and the sheath assembly, the sheath assembly being axially moveable relative to the fluid delivery element from a first position to a second position; wherein the fluid delivery element further comprises a fluid source connected to the sheath assembly proximal to the at least one radial seal and, when the sheath assembly is in the second position, the fluid source flows through a sequential fluid delivery path, through the sheath assembly proximal to the at least one radial seal, the first port, the inner lumen, the second port, the sheath assembly that is distal to the radial seal and via a distal opening disposed adjacent the electrode assembly.