A system comprising an electrosurgical device comprising: a cannula comprising one or more electrically insulated portions and one or more electrically exposed conductive portions, the cannula defining one or more lumens; and an elongate member disposed within one of the one or more lumens such that at least a portion of the elongate member is in electrical and thermal contact with the cannula, wherein the elongate member is disposed within the one of the one or more lumens such that at least a portion of the elongate member is in electrical contact with at least one of the one or more electrically exposed conductive portions for delivering energy from the elongate member to the at least one electrically exposed conductive portion, and such that at least a portion of the elongate member is in thermal contact with at least one of the one or more electrically exposed conductive portions for cooling the at least one electrically exposed conductive portion, wherein the elongate member is adapted to be internally cooled; characterized in that the elongate member comprises at least two internal tubes for delivering fluid to a distal region of the elongate member, wherein the at least two internal tubes comprise a first internal tube having a proximal end connected to a reservoir of a first fluid for delivery to the distal region of the elongate member and a second internal tube having a proximal end connected to a separate reservoir of a second fluid for delivery to the distal region of the elongate member, wherein the first and second fluids are selected to react endothermically when mixed, wherein the two reservoirs, the first fluid, and the second fluid are comprised by the system. a cannula comprising one or more electrically insulated portions and one or more electrically exposed conductive portions, the cannula defining one or more lumens; and an elongate member disposed within one of the one or more lumens such that at least a portion of the elongate member is in electrical and thermal contact with the cannula, wherein the elongate member is disposed within the one of the one or more lumens such that at least a portion of the elongate member is in electrical contact with at least one of the one or more electrically exposed conductive portions for delivering energy from the elongate member to the at least one electrically exposed conductive portion, and such that at least a portion of the elongate member is in thermal contact with at least one of the one or more electrically exposed conductive portions for cooling the at least one electrically exposed conductive portion, wherein the elongate member is adapted to be internally cooled; characterized in that the elongate member comprises at least two internal tubes for delivering fluid to a distal region of the elongate member, wherein the at least two internal tubes comprise a first internal tube having a proximal end connected to a reservoir of a first fluid for delivery to the distal region of the elongate member and a second internal tube having a proximal end connected to a separate reservoir of a second fluid for delivery to the distal region of the elongate member, wherein the first and second fluids are selected to react endothermically when mixed, wherein the two reservoirs, the first fluid, and the second fluid are comprised by the system.