TRANSURETHRAL NEEDLE ABLATION (TUNA) OF THE PROSTATE USING LOW-LEVEL RADIOFREQUENCY ENERGY - AN ANIMAL EXPERIMENTAL-STUDY

Transurethral needle ablation of the canine prostate using low level r adiofrequency energy was examined for efficacy and safety in a two-sta ge experimental study. Eleven mongrel dogs were treated via the bladde r neck and prostatic urethra using a specially designed cathether thro ugh which needle antennas were advanced into the prostatic tissue. A r adiofrequency energy source was connected to the catheter and used to create tissue ablation. In the first 5 dogs this was found to be feasi ble. Necrotic lesions were created around the needle antennas. Typical ly, lesions were 1 cm in diameter and conical in shape. The actual siz e of the lesion was directly related to power level used, time of abla tion and length of needle deployment. In the next 6 dogs temperatures were simultaneously measured in the prostatic urethra and rectum. The dogs were sacrificed 0, 2, 2, 14, 28 and 30 days following the experim ents and the bladder, prostate and anterior rectal wall were removed e n bloc and examined macroscopically and histopathologically for any ch anges. It was found that urethral temperatures increased to 46.1-degre es-C on the average while rectal temperature did not rise during the e ntire experiment. The lesions found in the prostate were similar to th ose found in the first 5 dogs. No macroscopic or histopathologic chang es were noted at the bladder base, anterior rectal wall or in the dist al prostatic urethra. It was concluded that prostatic tissue ablation in the canine model can be achieved safely and could justify the start of human trials.