Transurethral needle ablation (TUNA): safety, feasibility, and tolerance of a new office procedure for treatment of benign prostatic hyperplasia.

Many attempts have been made to develop a method for treating benign prostatic hyperplasia (BPH) that is minimally invasive, efficacious, and low cost. The transurethral needle ablation (TUNA) device has recently been developed to treat BPH by selectively ablating hyperplastic prostatic tissue. A special catheter incorporates needles that deliver low-level radiofrequency power directly to a very localized area of the prostate. The needles have adjustable shields to protect the urethra if desired or necessary. It is positioned via transrectal ultrasound or direct vision. A pilot study was performed in patients to evaluate TUNA feasibility via histopathological measurement of thermal lesion size and TUNA safety by: (1) monitoring urethral and rectal temperatures; (2) assessing the ability to localize lesions, and (3) determining patient tolerance of the procedure without anesthesia. Twenty patients were treated using TUNA prior to scheduled retropubic prostatectomy. The surgical prostatic specimens were recovered from 1 day to 1 month after TUNA, were step-sectioned, and examined histologically. Patients were 68 years old on average with prostate weight varying from 14 to 88 g. The TUNA procedure averaged 27 min, 4 lesion treatments per prostate, and 4-15 W of power applied for 3 min. Proximal lesion temperature was about 40-50 degrees C with central lesion temperatures of about 80-100 degrees C. Urethral temperature averaged 37-42 degrees C and rectal temperature remained unchanged. Macroscopic examination of the specimens demonstrated localized lesions averaging 12 x 7 mm. Microscopic examination showed larger lesions of extensive coagulative necrosis averaging 30 x 15 mm. Specific immunohistochemical staining showed destruction of all tissue components.(ABSTRACT TRUNCATED AT 250 WORDS)