Abstract: A cryogenic surgical instrument and method of manufacturing the same are described. The instrument is a cryosurgical probe having concentrically arranged cryogenic fluid supply and return tubes extending through a concentric handle portion into a closed end probe shaft wherein the handle portion and a substantial length of the probe shaft are evacuated to provide a layer of thermal insulation between the cryogenic fluid supply and return tubes and the exterior of the instrument. All the parts of the probe structure are joined by vacuum brazing method carried out in an evacuated furnace. The method involves assembling the probe parts into sub-assemblies which are vacuum brazed at a temperature of at least about 1000.degree. F. and a vacuum of at least about 1.times.10.sup.-3 Torr. The sub-assemblies are then assembled into the final probe assembly which is likewise vacuum brazed.

Abstract: The present invention is directed to a closed circulation tissue warming apparatus for use during surgery to maintain the temperature of tissues at a desired level and to a method of using the apparatus in prostate surgery particularly during transperineal cryoablation of the prostate gland in human males to maintain the temperature of the urethral tissues and thereby prevent urethral sloughing. It may also have utility where it is desired to lower the temperature of surrounding tissues, such as during laser ablation. The apparatus includes a multi-lumen catheter inserted into the urethra and connected to a fluid warming and circulation control means whereby warmed water is circulated through the lumens at a controlled flow rate and temperature. The concentric lumen structure of the catheter provides improved flow and even temperature maintenance along the length of the catheter and the urethra.