UROLOGICAL SURVEY   ( Download pdf )

 

NEUROUROLOGY & FEMALE UROLOGY

Does uroflow predict ISD?
Smith PP, Appell RA
Scott Department of Urology, Baylor College of Medicine, Houston, Texas, USA
Neurourol Urodyn. 2008; 27: 40-4

  • 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.

  • Editorial Comment
    The authors examine the correlation of catheter free uroflow to the presence of intrinsic sphincter deficiency during urodynamic evaluation in a population of patients with symptomatic pelvic organ prolapse. This population was selected in that it was conjectured that the pelvic organ prolapse group would offer the truest evaluation of urethral sphincter function since the impact of the external sphincter mechanism would be minimized secondary to their anatomic pathology. The authors found that catheter free uroflow rates were not correlated to leak point pressures in this select population of women (symptomatic pelvic organ prolapse and stress urinary incontinence).
    An excellent article from a noted leader in the field. The introduction and discussion section alone are worth reading for the commentary and description of the continence control mechanisms. I found it interesting that in review of the tables and the results section there was no notation of variability of voiding pattern: pure Valsalva voiders; combined detrusor contraction with Valsalva voiding; and voiders who empty their bladder by relaxing the pelvic floor. All who have evaluated female voiding dysfunction have found the noted voiding patterns at times to be very confounding with regards to analysis secondary to their variability (1).

Reference
1. Lemack GE: Urodynamic assessment of bladder-outlet obstruction in women. Nat Clin Pract Urol. 2006; 3: 38-44.

Dr. Steven P. Petrou
Associate Professor of Urology
Chief of Surgery, St. Luke’s Hospital
Associate Dean, Mayo School of Graduate Medical Education
Jacksonville, Florida, USA