The effects of transurethral needle ablation and resection of the prostate on pressure flow urodynamic parameters: analysis of the United States randomized study

Abstract

Purpose: We evaluated the effects of transurethral needle ablation and prostate resection on pressure flow urodynamic parameters in men with benign prostatic hyperplasia (BPH), compared symptomatic and objective parameters of efficacy 6 months after initial treatment, and determined whether urodynamic assessment may predict symptomatic improvement.

Materials and methods: We enrolled 121 patients with clinical BPH, American Urological Association symptom index of 13 or greater and maximum urinary flow of 12 ml. per second or less in a randomized study comparing transurethral needle ablation to prostate resection at 7 institutions in the United States. Patients underwent baseline and followup assessments at 6 months, including pressure flow studies.

Results: Patients who underwent each procedure had statistically and clinically significant improvement in symptom index, BPH impact index and quality of life score. After needle ablation and prostate resection maximum flow improved from 8.8 to 13.5 (p<0.0001) and 8.8 to 20.8 ml. per second (p<0.0001), detrusor pressure at maximum flow decreased from 78.7 to 64.5 (p = 0.036) and 75.8 to 54.9 cm. water (p<0.001), and the Abrams-Griffiths number decreased from 61.2 to 37.2 (p<0.001) and 58.3 to 10.9 (p<0.001), respectively. At 6 months the differences in transurethral needle ablation and prostate resection were significant in terms of maximum flow (p<0.001) and the Abrams-Griffiths number (p<0.001) but not detrusor pressure at maximum flow or symptom assessment tools. The presence or absence of urinary obstruction at baseline did not predict the degree of symptomatic improvement in either treatment group.

Conclusions: Transurethral needle ablation and prostate resection induce statistically and clinically significant improvement in various quantitative symptom assessment questionnaires at 6 months. The parameters of free flow rates and invasive pressure flow studies also significantly improve after each treatment. However, transurethral prostate resection induces a significantly greater decrease in the parameters of obstruction. Baseline urodynamic parameters do not predict the degree of symptomatic improvement and they may not be helpful in patient selection for transurethral needle ablation.