Ballooning of the foreskin and physiological phimosis: is there any objective evidence of obstructed voiding?

OBJECTIVES To determine whether physiological phimosis with or without ballooning of the prepuce is associated with noninvasive urodynamic or radiological evidence of bladder outlet obstruction. PATIENTS AND METHODS From August 2001 to October 2002 all boys with a foreskin problem and referred to one paediatric surgeon were assessed in special clinics. Those with physiological phimosis were recruited for the study and had upper tract and bladder ultrasonography (US), followed by uroflowmetry and US-determined postvoid residual urine volumes (PVR). Data were compared between boys with and with no ballooning of the prepuce. The project was approved by the local research ethics committee and informed consent was obtained from all study participants. RESULTS In all, 54 patients were referred for circumcision; 32 boys with physiological phimosis completed the uroflow and US investigations. Ballooning of the foreskin was present in 18 boys (mean age 6.8 years, range 3-12); 14 had physiological phimosis with no ballooning (mean age 6.5 years, range 4-11). Upper tract US and bladder wall thickness were normal in all boys. The mean maximum urinary flow rate (Q(max)) was not significantly different in boys with ballooning and those without (mean 15.3 mL/s, sd 4.4, range 9-24, vs 15.4, sd 2.9, range 10.7-20, P = 0.96). In addition, all Q(max) values were within the normal range when correlated with voided volume and compared with age-related nomograms. Most boys had flow rate patterns showing a normal bell-shaped curve; a few (9%) had subtle changes in the flow-rate profile, with either a plateau-type curve or slow initial increase in flow and prolonged time to achieve Q(max). The two groups had comparable mean PVRs (3.5 mL, sd 5.1, range 0-18 with ballooning vs 6.1, sd 10.7, range 0-38 without, P = 0.37). Only one patient had a marginally abnormal PVR. CONCLUSIONS Physiological phimosis with or without ballooning of the prepuce is not associated with noninvasive objective measures of obstructed voiding. Minor abnormalities in the flow-rate pattern in this patient group deserve further study.