Does uroflow predict ISD?

AIM: The term superflow has been given to abnormally high flow rates in women, and has been thought to be indicative of intrinsic sphincteric deficiency (ISD), as ISD is associated with low urethral pressure. Pelvic organ prolapse (POP) damages the sphincteric mechanism extrinsic to the urethra. The aim of this study was to determine if ISD can be predicted from voiding flow rates in women with symptomatic POP.

METHODS: The charts of 82 patients who had undergone surgery for repair of symptomatic vaginal prolapse were reviewed. Uroflow and urodynamic endpoints were compared between dry and stress incontinent patients, and correlations between abdominal leak point pressures (LPP) and pressure/flow data evaluated.

RESULTS: Average maximum flow (Q(max)) at uroflow was greater than at urodynamics with no significant difference in voided volumes. Twenty eight patients were found to have urodynamic stress incontinence (SUI), and an additional 19 to have "occult" stress incontinence. Patients with SUI had higher flow rates at urodynamics than continent patients. Voiding detrusor pressures and flow rates were not different when categorized by LPP cutoffs of 100 and 60 cm/w. Abdominal leak point pressure did not significantly correlate with any uroflow or urodynamic pressure/flow parameter.

CONCLUSIONS: Flow rates, whether determined by uroflow testing or at urodynamics, are not predictive of ISD as defined by a low abdominal leak point pressure, in patients with symptomatic POP. Either the effect of ISD on flow rates is a non-linear complex relationship or LPP does not adequately define ISD.