Phase separation of cryogen in cryosurgical instrument

A cryosurgical instrument comprising:

• a shaft having a pointed distal end and a proximal end adapted and configured to receive an inflow of cryogen and to exhaust a flow of expanded cryogen;
• a core disposed within the shaft;
• a cryogen delivery tube having a helical portion that spirals around the core and delivers a flow of cryogen toward the pointed distal end of the shaft, the delivery tube being in fluid tight contact with the core and an inner surface of the shaft;
• and
• a cryogen return tube having a helical portion that spirals around the core, the return tube configured to accept, at an upstream end thereof near the distal pointed end of the shaft, a return flow of cryogen,
• wherein the respective spirals of the helical portions of the tubes are respectively spaced,
• wherein the helical portions spin a cryogen flowing therethrough so as to promote phase separation of the cryogen,
• wherein the spaced spirals of the helical portions of the tubes, the core, and the inner surface of the shaft cooperate so as to form a spiraling cryogen return pathway that spins a cryogen flowing therethrough so as to promote phase separation of a flow cryogen therethrough, and
• wherein expanded cryogen may be exhausted via the return tube or the return pathway.

A cryosurgical instrument, comprising:

• a shaft having a pointed distal end and a proximal end adapted and configured to receive an inflow of cryogen and to exhaust a flow of expanded cryogen;
• and
• a core disposed within the shaft and in fluid tight contact with an inner surface of the shaft, the core having two exterior spiraling threads that cooperate with the inner surface of the shaft to form first and second respective spiraling pathways, a first spiraling pathway being a cryogen delivery pathway, the second spiraling pathway being a cryogen return pathway,
• wherein the cryogen delivery pathway is configured to deliver a received flow of cryogen to a downstream end near the pointed distal end, and
• wherein the cryogen return pathway is configured to accept, at an upstream end thereof, a return flow of cryogen from the distal pointed end.