High-intensity focused ultrasound energy for benign prostatic hyperplasia: clinical response at 6 months to treatment using Sonablate 200.

We evaluated the safety and efficacy of high-intensity focused ultrasound (HIFU) using a modified Sonablate 200 and compared the clinical response with that of the prototype Sonablate at 6 months after treatment. Since 1995, 35 patients ages 66 +/- 7 years underwent HIFU with the Sonablate 200 for symptomatic benign prostatic hyperplasia (BPH) under low spinal anesthesia. The estimated prostatic volume was 40.4 +/- 4.8 cc before treatment. A silicon-coated 16F latex catheter was indwelling during determination of the therapy zone and treatment so that critical tissue at the midline was thoroughly treated. Twenty-two patients were analyzed with complete 6-month follow-up data. Side effects were transient urinary retention in four of these patients, hematuria in five, and hematospermia in eight. Peak urinary flow rate increased from 7.4 +/- 4.0 mL/sec to 11.4 +/- 4.0 mL/sec (P < 0.001) (54% increase). During the same period, the mean International Prostatic Symptom Score decreased from 20.4 +/- 7.1 to 9.0 +/- 7.5 (P < 0.001) (56% decrease). Quality of Life score improved from 5.4 +/- 0.6 to 2.4 +/- 1.3 (P < 0.001). Magnetic resonance imaging by means of an endorectal surface coil revealed significant coagulative necrosis areas in the periurethral gland at 1 month on T2-weighted images. These data demonstrate that HIFU for BPH using the Sonablate 200 produced a better clinical response than the prototype Sonablate and is expected to provide long-term durability of the response.