A Thermal Protective Urethral Heater Applied to Modulate the Prostate Cryoablation Area

BACKGROUND: Urethral warmer and cryoheater are invented and applied in cryoablation to overcome urethral cryoinjury, but these devices cannot be fixed and precisely control the released heat which excessively reduces the effective ablation area. Current warmers enlarge the operation difficulty and decrease the precision in temperature control. OBJECTIVE: A reformed catheter termed urethral heater aims to protect the urethra and simultaneously control the released heat so as to meet the aid of doctors' convenient operation in effective therapy, device fixation and precise heat controllability. MATERIALS AND METHODS: In this paper, the temperature controller combined with temperature monitor was used to control the heating behavior of the urethral heater with the initial active temperature. The controllability and thermal protection of the urethral heater was simulated and tested, which compared with that of urethral warmer. RESULTS: During the trials in vitro, the lowest temperature at the urethra surface is -3.7°C when one cryoprobe was introduced in the cryoablation for 15 min and -15.3°C with two cryoprobes. Above all, the effective cryoablation area increased with the decline of initial active temperatures. CONCLUSION: The urethral heater is able to prevent the urethra from irreversible damage and modulate the ablation area. The delay of heat is a new way to decline the recurrence rate and facilitate the desire of aconuresis during the cryoablation.