Purpose: We determined patient tolerance and the sequence of histopathological changes of thermal injury and healing of the prostate after treatment with a novel, rapid, high temperature, liquid filled, flexible balloon thermotherapy system.
Materials and methods: A total of 17 patients scheduled for prostatic surgery received preoperative high temperature water balloon thermotherapy. In 13 patients intraprostatic, urethral and rectal temperatures were continuously monitored and determined using stereotactic thermal mapping with the patient under spinal anesthesia. The remaining 4 patients had lidocaine gel as the only method of pain control. Patient discomfort was recorded at all times during the procedure. After treatment a prostatic stent was left in place until surgery or spontaneous voiding. Serial sections of the resected prostates were evaluated pathologically with mapping.
Results: Treatment was well tolerated by all patients. Prostates were enucleated (in 12 patients) or entirely removed (in 5) at a mean of 35 days (range 15 to 173) after thermotherapy. The predominant pathological findings in the early phase were uniform periurethral hemorrhagic necrosis, extensive urothelial denudation and varying degrees of inflammation. The mean radial depth of necrosis (from the urethra to the viable tissue border) was 0.9 cm (range 0.6 to 1.5) involving a mean of 16% of the prostatic adenoma (range 7.8% to 32%). In the late (resolution) phase necrotic tissue had been replaced by scar tissue (fibrosis and hyalinization) with a mean radial depth of 0.13 cm (range 0.01 to 0.24), and the urothelium had largely regrown along the urethra.
Conclusions: The fast liquid ablation system for hyperplasia is a new minimally invasive treatment that induces considerable thermal injury to the prostate with uniform necrosis and subsequent sloughing of dead tissue, allowing enlargement of the urethral lumen.