Urethral Perfusion for Cryoablation of the Prostate

Abstract

Cryosurgery is an emerging treatment method for prostate cancer patients that may expand the scope of practice for perfusionists. Because of the low temperatures needed to cryogenically destroy cancerous tissue, damage to the urethra and bladder may cause incontinence and impotence. As a result of this associated morbidity, an extracorporeal circuit was constructed by the perfusionists at the University of Nebraska Medical Center (Omaha, NE). This urethral perfusion circuit provides a way to maintain normothermic urethral and bladder temperatures during cryogenic procedures, thus preventing trauma to the urethra and bladder. Five patients with a mean age of 73.3 ± 3.0 years diagnosed with localized prostate cancer (Stage A, B, C) were offered cryosurgery using urethral perfusion to treat their cancer. After induction of general anesthesia, a specially designed urethral catheter was inserted. Quarter-inch tubing was attached to barbed connections on the catheter and the free ends were then attached to the circuit. This extracorporeal circuit consisted of a heater/cooler, a twin roller pump, a cardioplegia heat exchanger, and temperature and pressure monitoring devices at the inlet and outlet sites on the catheter. Normal saline was circulated through the tubing of the urethral perfusion circuit to maintain flow rates of 200-400 ml/min, with the circuit pressure not exceeding 300 mmHg. Average urethral perfusion time was 139.3 ± 17.7 minutes. Inlet temperature of the catheter was kept at 42° C to maintain an average bladder temperature of 38.2 ± 2.3° C. All of the patients tolerated the procedure well and were ambulating without assistance on postoperative day one. With the exception of one patient with acute postoperative anuria, patients were discharged on the first postoperative day. Cryosurgery of prostate cancer using urethral perfusion has the potential to serve as a unique practice opportunity for perfusionists.