Uroflow via stenotic urethra.

A DANTEC 2100 mictometer type 21C10 with uroflow transducer type 21KO2 was used for investigation of 50 men with urethral strictures (mean age 59 +/- 14 years). The patients underwent a total of 334 clinical evaluations of replicate voiding (minimum 4, maximum 16) before and after successful urethral dilatation on an outpatient basis. Using t-paired comparison test, significant increase in maximum urinary flow rate (P less than 0.01) after the treatment procedure was evidenced in each of the patients. The variability of other urinary flow parameters suggested a lower significance in evaluation of urine stream quality. The McNemar test showed a significant shift from one to another zone of classification suggested by Drach et al. (P less than 0.01), i.e. 64% of patients reached normal or overlap zone in the first spontaneous voiding after urethral dilatation. Furthermore, no significant difference could be established with one-way ANOVA between urodynamic variables of mean values of repetitive voidings in cases of urethral stenosis of different aetiology either before or after urethral dilatation (P greater than 0.05), suggesting that urethral stenoses of different aetiology are characterized by similar urodynamic features. A highly significant linear correlation was found between the maximum flow rate and the voided volume only after urethral dilatation (r = 0.522, P less than 0.01), while correlation with urethral sound sizes could not be established (r = 0.207, P greater than 0.5). We conclude that uroflowmetry provides reliable information on the patient's ability to void. The use of maximum flow rate may predict the time at which urethral dilatation becomes necessary and provides objective evidence of the efficacy of treatment.