Transurethral needle ablation (TUNA): histopathological, radiological and clinical studies 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 the size of the thermal lesion and TUNA safety. Fifty patients have been treated, twenty-five 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 69 years old on average with a prostate weight varying from 14 to 88 g. The TUNA procedure averaged 30 minutes, 4 lesion treatments per prostate, and 4-15 W of power applied for 3 to 5 minutes. Proximal lesion temperature was about 40-70 degrees C with central lesion temperatures of about 110 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 for 3 mins. and 10 x 17 for 5 mins. treatment. Microscopic examination showed larger lesions of extensive coagulative necrosis up to 35 x 15 mm. Specific immunohistochemical staining showed destruction of all tissue components. Preservation of the urethra and capsule integrity were noted. Magnetic resonance imaging performed in vivo and ex vivo showed lesions in the prostate corresponding to the recovered surgical specimen. All patients were treated without anesthesia and tolerated the procedure well. Of the 9 patients treated for chronic retention, 6 recovered voiding within 48 hours. Three month follow-up in 11 patients showed significant improvement in both objective and subjective parameters. Because of good lesion localization and maintenance of a normal rectal temperature TUNA appears to be safe. The feasibility of its widespread use was shown by the creation and sustainability of adequately sized lesions and good tolerance as an outpatient treatment. Ongoing clinical studies are evaluating the sustained efficacy of the procedure.
Schulman
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CC
Department of Urology, Erasme Hospital, University Clinics of Brussels, Belgium.
Zlotta
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AR
D000368:Aged; D000369:Aged, 80 and over; D000556:Ambulatory Surgical Procedures; D017115:Catheter Ablation / Q000009:adverse effects / Q000295:instrumentation; D006801:Humans; D008297:Male; D009339:Needles; D010865:Pilot Projects; D011467:Prostate / Q000473:pathology; D011470:Prostatic Hyperplasia / Q000175:diagnosis / Q000601:surgery*; D013997:Time Factors