A comparison of urethral profilometry using microtip and fiberoptic catheters

This paper compares urethral profilometry measurements using two different types of catheter: the Millar microtip transducer and the FST fiberoptic catheter. Outcome variables were functional urethral length (FUL), maximum urethral closure pressure (MUCP), and mean pressure/transmission ratio (PTR). Thirty women presenting to the urodynamics laboratory with symptoms of stress urinary incontinence were evaluated with both catheters. All subjects underwent two passive urethral pressure profiles and two dynamic (cough) urethral pressure profiles with each catheter. For FUL and MUCP, the means of the two passive measurements were compared between catheters. For PTR, the means of the two dynamic measurements were compared between catheters. There was no difference in FUL between the two catheter types. The FST measurements of MUCP and PTR were lower than the microtip measurements. Twenty percent of patients would have been diagnosed with low-pressure urethra with the FST catheter, but not with the microtip catheter. Caution must be used when applying urethral measurements taken with the fiberoptic catheters to standards set with microtip catheters.