Urodynamic implications of benign prostatic hyperplasia.

By the age of 60, about 70% of men have developed benign prostatic hyperplasia (BPH), and 85%-95% of these have symptomatic dysfunction of the lower urinary tract, 10%-20% undergoing prostatectomy. Although transurethral resection of the prostate is generally considered to be a safe and effective surgical procedure, it has recently been shown that immediate surgery, as opposed to a wait-and-see strategy, leads to a 1-month reduction in life expectancy. In 10%-15% of the patients who undergo surgery, the postoperative result is unsatisfactory as symptoms persist. Between 4% and 40% of patients undergoing prostatectomy become impotent. A urodynamic study with a scope extending beyond that of the standard urological examination is therefore needed to help reduce the number of treatment failures. The value of preoperative cystometry is questionable, since preoperative documentation of detrusor instability has no bearing on the postoperative result. Measurement of urinary flow, in contrast, is of predictive value in BPH, patients in whom the maximum urinary flow before surgery is more than 15 ml/s having significantly worse results of surgery than those with a maximum urinary flow of less than 15 ml/s before surgery. Further data relevant to the prognosis are yielded by pressure-flow investigations, which allow a quantitative estimate of the degree of obstruction.(ABSTRACT TRUNCATED AT 250 WORDS)