Diagnostic power of the noninvasive condom catheter method in patients eligible for transurethral resection of the prostate.

ABSTRACT

AIMS: The aim of this study was to determine the accuracy of the non-invasive condom catheter method for diagnosing B(ladder) O(utlet) O(bstruction) in patients eligible for T(rans)U(rethral) R(esection) of the P(rostate). METHODS: A group of 71 patients eligible for TURP on clinical grounds were invasively and non-invasively studied. On the basis of invasive pressure-flow studies they were stratified into obstructed, equivocal or unobstructed, according to the International Continence Society standard. Subsequently they were diagnosed non-invasively on the basis of a free flowrate measurement, or on the basis of the free flowrate measurement plus the isovolumetric bladder pressure measured with the condom catheter method. R(eceiver) O(perating) C(haracteristic)s were calculated. RESULTS: The A(rea) U(nder) the (RO)C for discriminating unobstructed/equivocal patients from obstructed patients was 0.68 in our population. This improved to 0.84 for the 50 patients in whom the isovolumetric bladder pressure was not underestimated by the non-invasive method. CONCLUSIONS: In our population of TURP patients, the low flowrates affected the accuracy of the condom method to a degree that it did not perform better than a free flowrate measurement, which performed remarkably well. By excluding measurements in which the condom pressure underestimated the isovolumetric bladder pressure this method may contribute to a more accurate, patient friendly diagnosis of BOO in these patients. In the present study this exclusion was done by comparison with an invasive pressure measurement. A practical non-invasive test would necessitate a non-invasive exclusion criterion, which might be based on the risetime of the condom pressure.