Bladder-outlet obstruction--assessment of symptoms

Assessment of symptoms plays a central role in the evaluation of men with suspected bladder-outflow obstruction (BOO) secondary to benign prostatic hyperplasia (BPH). It is on the basis of symptoms that treatment designed to relieve outflow obstruction is recommended. However, a variety of studies have suggested that a considerable proportion of men presenting with suspected outflow obstruction are not obstructed as determined by pressure-flow criteria. The relationship between many so-called "obstructive" symptoms and BOO has not yet been defined. Furthermore, all previous studies have defined BOO on the basis of urethral resistance factors, which are now regarded as outdated. Using current concepts of urethral pressure-flow relationships, we studied in detail the relationship between the "obstructive" symptoms of BPH, objective evidence of abnormal voiding and BOO. Only the symptoms of hesitancy and poor flow were found to be significantly related to BOO. The symptoms of straining to void, intermittency, terminal dribbling and feeling of incomplete bladder emptying were not specific for BOO. Objective evidence of an intermittent flow pattern and of terminal dribbling do, however, have a high specificity and positive predictive value for BOO. The assessment of men with lower-urinary-tract symptoms must include objective tests of voiding function. A better understanding of the pathophysiology of lower-urinary-tract symptoms should lead to an improved symptomatic outcome of prostatectomy.