The uroflowmetry in normal men and after prostatectomy.

OBJECTIVE

This study was designed to determine and compare the uroflow parameters of normal men and patients after prostatectomy in order to investigate the flow rate expression in men without bladder outlet obstruction.

MATERIALS AND METHODS

Five hundred and fourteen men aged from 17 to 84 years who subjectively felt that their urination was normal and were objectively demonstrated to be without prostatic hyperplasia were enrolled in the normal group. For comparison, 356 patients after prostatectomy were also included as age-matched treated groups. Both groups were further divided into age-based subgroups. Uroflowmetry and transrectal sonography were performed in all the subjects. The uroflow parameters and prostatic volumes of different patient groups were compared. Regression analysis was used to estimate the correlation between maximal flow rate (Qmax) and age, as well as between Qmax and volume.

RESULTS

The results show that voided volume decreased with age in asymptomatic men without prostatic hyperplasia. The decreased voided volume with age resulted in declining Qmax in normal men. In patients after prostatectomy, however, infravesical obstruction affected detrusor contractility more with age and resulted in a declining flow rate expressed in similar voided volumes. In normal men, the mean Qmax was 20.7 +/- 7.3 ml/s in a mean voided volume of 290.7 +/- 123.2 ml. As age increased, smaller bladder capacity resulted in lower flow rate expressions, but the corrected Qmax showed no significant differences.

CONCLUSION

Normal elderly men without prostatic hyperplasia can have good urinary flow and good bladder energetics. Asymptomatic men with low flows might have incipient infravesical obstructions. Patients after prostatectomy had impaired detrusor contractility that resulted in a low flow rate expression with age.