IN-VITRO AND IN-VIVO ASSESSMENT OF URETHRAL WARMING CATHETERS FOR THETRANSPERINEAL CRYOABLATION OF PROSTATIC-CARCINOMA

Objective To evaluate the two most common urethral warming catheters c urrently available for their effectiveness in preventing urethral inju ry in an animal model and thus during transperineal cryosurgery for th e treatment of prostate cancer. Patients, materials and methods The wa rming efficiency of the variable-diameter thin latex-balloon catheter (Cook, Australia) and the fixed-diameter PVC catheter (Candela, USA) w ere evaluated in a water-bath. A sheep model was then used for subsequ ent experiments to further evaluate the better catheter. The technique used for the insertion of the Cook catheter in a series of 33 patient s treated with prostate cryosurgery is also described. Results In vitr o, the Cook catheter was more effective (P<0.01) than the Candela cath eter in preventing localized cooling. In vivo, results in five animals showed that the urethral epithelium was viable in all sections that h ad been protected by the catheter and focally denuded or necrotic in t hose sections not protected, with each animal used as its own control (P<0.01 Fisher's exact test). The 33 patients treated while using the Cook catheter had no subsequent complications. Conclusion The urethral warming catheter currently in use for prostatic cryosurgery in Austra lia is more effective in vitro than its competitor and is effective in preventing urethral injury in vivo.