Phase separation of cryogen in cryosurgical instrument

A cryosurgical instrument comprising:

• a shaft having a closed distal end defining an expansion chamber and a proximal end adapted and configured to receive an inflow of cryogen and to exhaust a flow of cryogen that has expanded in the expansion chamber;
• a core disposed along a longitudinal axis of the shaft;
• and
• a helical cryogen delivery tube that spirals around the core, is in fluid tight contact with the core, and is in fluid tight contact with an inner surface of the shaft, the respective spirals of the delivery tube being respectively spaced,
• wherein, spirals of the cryogen delivery tube spin the inflow of cryogen during delivery to the expansion chamber, and
• wherein the spaced spirals of the cryogen delivery tube, the solid core, and an inner surface of the shaft cooperate so as to form a spiraling cryogen exhaust pathway that delivers an exhaust flow of cryogen from the expansion chamber and spins the exhaust flow as the exhaust flow flows from the expansion chamber.

A cryosurgical instrument having a hollow shaft having a closed distal end forming a tip, the instrument comprising:

• a phase separator that includes:
• a core disposed within the shaft and extending along a longitudinal axis of the shaft;
• and
• a coiled cryogen delivery tube that spirals around the longitudinal axis such that the respective spirals are spaced from each other,
• wherein the respective spirals are in fluid tight contact with the core and an inner surface of the shaft,
• wherein the spaced spirals of the cryogen delivery tube, the core, and an inner surface of the shaft cooperate so as to form a spiraling cryogen exhaust pathway that spins a flow of expanded cryogen flowing away from the tip.

A method, comprising:

• directing a flow of cryogen to an expansion chamber at a tip end of a shaft of a cryosurgical instrument via a spiraling delivery path;
• permitting cryogen in the expansion chamber to expand and cool at least the tip of the cryosurgical instrument;
• directing a flow of expanded cryogen away from the tip of the cryosurgical instrument via a spiraling exhaust path;
• and
• spinning the flow of cryogen during the directing a flow of cryogen to an expansion chamber;
• spinning the flow of expanded cryogen during the directing a flow of expanded cryogen away from the expansion chamber,
• wherein the spiraling delivery path and the spiraling exhaust path spiral around a core and between the core and an inner surface of a shaft of the cryosurgical instrument, and
• wherein the spiraling delivery tube is in fluid tight contact with an inner surface of the shaft and the core, the spirals of the cryogen delivery tube are spaced from each other, and the spiraling delivery path, in cooperation with the core and the inner surface of the shaft, form the spiraling exhaust pathway.