Ambulatory Urodynamics in Asymptomatic,Young, Healthy Male Volunteers

Objectives: To assess the incidence of detrusor overactivity and reproducibility of data from ambulatory urodynamic monitoring (AUM) in male volunteers. Methods: Sixteen asymptomatic healthy male volunteers with a mean age of 26.3 years (range: 22–30) underwent AUM by natural filling cystometry followed by a pressure/flow study. The studies were repeated three times. Results: Detrusor overactivity (DO) was detected in six subjects (37.5%), but clinically significant detrusor overactivity was noted only in three (18.8%). Q_max, detrusor opening pressure, and P_detQ_max were similar among the three measurements. The bladder outlet obstruction index (BOOI) varied, and there was a significant difference between the first and third measurements (P = 0.0371). Obstruction grade was ranked as unobstructed in all studies for 13 subjects, equivocal (BOOI 45 and 46) in one subject, and both unobstructed and equivocal (BOOI 30, 43 and 30) in one subject. There was a significant difference in bladder contractility index (BCI) between the first and third studies (P = 0.0186). The BCI was always strong in five subjects, always normal in eight subjects, and strong to normal in three subjects. Conclusion: DO was found in 37.5% of male volunteers. BOOI and BCI may not be highly reproducible, and the third study may provide the best result if the first and second studies differ. However, 87.5% of subjects were rated as unobstructed and all subjects were rated as normal or strong, with the categories of obstruction and bladder contractility showing no change in most subjects. AUM with three studies seem adequate for the evaluation of lower urinary tract dysfunction in males.