An electrosurgical apparatus for coagulating tissue includes an elongated flexible
tube having a proximal end, a distal end and a source for supplying pressurized
ionizable gas to the proximal end of the tube. The apparatus also includes a hollow
sleeve made from a shape memory alloy having a generally curved austenite state
and displaying stress-induced martensite behavior. The hollow sleeve is restrained
in a deformed stress-induced martensite configuration within the tube and partial
extension of a portion of the hollow sleeve from the tube transforms the portion
of the sleeve from the deformed configuration to the generally curved austenite
configuration such that the gas is directed transversely at the issue. An electrode
ionizes the gas in the region between the sleeve and the tissue. Other embodiments
of the present disclosure also include a wire connected to the distal end of the
tube which movable from a first position wherein the tube is disposed in a generally
rectilinear, parallel fashion relative to the tissue to a second retracted position
wherein the distal end of the tube flexes at an angle to direct the gas towards
the tissue. Still other embodiments of the present disclosure include a corona
electrode for inducing ignition of the gas.
