A small, disposable cryosurgical probe having a self-contained liquid refrigerant supply can be operated in either a freeze mode or a defrost mode. During the freeze mode the refrigerant is conducted from the supply to the probe tip as a two phase fluid so that the probe can freeze tissue for a relatively long period with a limited refrigerant supply. To facilitate detaching the probe tip from tissue, a button on the probe is depressed which switches the probe to its defrost mode of operation wherein room temperature liquid refrigerant is conducted directly from the supply to the probe tip thereby immediately warming the tip. The probe may be cycled several times between its freeze and defrost modes before the refrigerant supply is exhausted.
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.
An improved defrostable cryosurgical instrument has a unitary in-line valve assembly that permits the assembly to be contained right in the instrument itself without making the instrument unduly large, heavy or upsetting its balance. By a fingertip control right in the instrument itself, the valve assembly can be controlled to route refrigerant through the instrument's tip to operate the instrument in a freeze mode, a defrost mode and to turn the instrument off, while simultaneously depressurizing the tip.
A catalytic thermal tip double catheter provides an alternative energy source for thermal angioplasty without the expense and technical support required for laser or electrical thermal angioplastic devices. The catalytic thermal tip catheter utilizes heat generated by the reactive of a stoichiometric ratio of oxygen and hydrogen gases catalyzed by a small piece of palladium sponge situated in a chamber adjacent to and enclosed by the metallic tip of the catheter, the vapors formed in the chamber generated being evacuated by a vacuum applied to an inner tube. Gas flow regulates catalytic thermal tip temperature which is monitored by a thermocouple positioned within the chamber. Vacuum and gas flow are controlled by an automatic or manual controller which is in direct communication with the temperature monitor.
A cryogenic surgical apparatus using a Sterling-cycle refrigerator connected by elongate flexible conduits to a cryosurgical device having an operating probe. The refrigerator includes a compressor having first and second cylinders with pistons positioned therein. The cryosurgical device includes a housing defining an expansion cylinder. An expansion piston and seals are positioned within the cylinder in such manner that first and second distinct expansion spaces are defined between opposite ends of the piston and ends of the cylinder. The operating probe is connected to or positioned on the end of the housing closest to the first expansion space. A regenerator is positioned in the end of the expansion piston closest to the first expansion space and has an outlet communicating with the first expansion space and an inlet communicating with a space intermediate the two expansion spaces. First and second flexible conduits connect the first and second cylinders of the refrigerator, respectively, to portions of the housing in communication with the inlet to the regenerator and the second expansion space. The first cylinder has a larger cross-sectional area than the second cylinder so that the operating probe is cooled when the compressor rotates in a first direction and is heated when the compressor rotates in an opposite direction. The phase relationship between the two pistons of the refrigerator is selected in such manner that movement of the expansion piston in a direction from the first towards the second of the two expansion spaces is opposed by an increasingly large pressure in the second expansion space.
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.
