A cryosurgical instrument having a tip which is cooled by the Joule-Thomson expansion of a pressurized gas. The gas is conveyed to the tip by an inlet tube and exhausts through an exhaust tube connected to the rear of a fitting. The tip is connected to the forward portion of the fitting. The rear and forward portions of the fitting are rotatably connected by a bearing coupling which enables the tip to be rotated independent of the inlet and exhaust tubes.

Cryosurgery may be performed by a microinvasive technique employing a novel cryosurgical probe. It is very thin, very long, and highly flexible. These characteristics are achieved by a construction consisting of a tube within a tube with no intermediate supporting elements therebetween. The probe is capable of being passed through a blood vessel and into the heart without external guidance other than the blood vessel itself.

Cryosurgical apparatus for necrosing human tissue or the like, the apparatus comprising a coolant supply where coolant comprising nitrous oxide, carbon dioxide, Freon 13 or Freon 23 is disposed within a container as a liquid under its own vapor pressure; pressure elevating means for increasing the vapor pressure so that it is greater than what it would be at room temperature and for maintaining the elevated vapor pressure substantially constant; a cryosurgical instrument having a hollow tissue contacting portion and a coolant expansion means disposed at the distal end of a feed passageway and a discharge path disposed outside of the passageway; and means for supplying the coolant to the feed passageway of the cryosurgical instrument so that the temperature of the coolant discharged through the expansion means is lowered. Means are also disclosed including switchable valve means connected to the discharge path of the cryosurgical instrument, the switchable valve means being switchable to a first position freeze mode to exhaust the coolant from the apparatus and to a second position defrost mode for closing the switchable valve means; defrost discharge means also connected to the discharge path of the cryosurgical instrument, the flow impedance of the defrost discharge means being substantially greater than that of the switchable valve means when it is in its first position freeze mode and substantially less than that of the switchable valve means when it is in its second position defrost mode.

In the cryo-probe, refrigerant is furnished from a high pressure, room temperature supply. Insulation of the refrigerant lines is unnecessary. Refrigerant flows through a pre-cooling heat exchanger in the probe and through a restrictor wherein the pressure drops. In accordance with the Joule-Thompson effect, the refrigerant expands and becomes cold and liquid is applied in the region of the cryo-tip to provide rapid cooling thereof. Expanded refrigerant gas at low pressure reverses direction and flows back from the cold tip in counterflow arrangement through the aforementioned heat exchanger to give a pre-cooling effect to the refrigerant incoming from the external supply. A second tube for conveying warm-up gas is located in the probe and extends to the cold tip. After cryosurgery is complete, the high pressure flow is stopped and warm gas is delivered to the tip in the probe at reduced pressure through the second tube from the same refrigerant supply as is used for cooling. Accordingly, the tip is rapidly warmed.

A cryosurgical probe for freezing human or animal tissue in a surgical procedure utilising the Joule Thomson effect. The probe is provided with a valve arrangement which enables selective purging and freezing cycles to be employed in rapid succession, and remote from the Joule-Thomson nozzle. In this way purging is limited to those parts of the probe which are affected by moisture contamination during the normal pre-sterilising process, and without interference with the Joule-Thomson nozzle.