Patent ID: 8709005

Claim:
A cryosurgical instrument comprising: a shaft having a closed distal end defining an expansion chamber and an open proximal end adapted and configured to receive an inflow of cryogen and to exhaust a flow of expanded cryogen; and a heat exchanger comprising: a solid core element extending along a longitudinal axis of the heat exchanger; and first and second cryogen delivery tubes, the first cryogen delivery tube including an uncoiled portion extending along the longitudinal axis and a coiled portion that spirals around and contacts the solid core element, the second cryogen delivery tube having a coiled portion that spirals around and contacts the uncoiled portion of the first cryogen delivery tube, wherein the coiled portions are spaced apart, and wherein the spirals of the cryogen delivery tubes are spaced from each other and in fluid tight contact with an inner surface of the shaft so as to form a spiraling cryogen exhaust pathway from the distal end of the shaft to the proximal end of the shaft.