Urethral pressures: analysis of transmission pressure ratios

Transmission pressure ratio (TPR) analysis of urethral pressure profilometry data has been advocated for the diagnosis of genuine stress incontinence (GSI). However, the clinical usefulness of the technique has not been adequately evaluated. Using videourodynamics as the gold standard, the TPR results of 150 continent women and 153 with GSI have been compared. The mean TPR for each quartile of the functional urethral length was computed, as was the maximum TPR value (TPR-max) and the position on the urethra where it occurred (TPR-mode). There was a statistically significant difference between the 2 groups for TPR values in the distal 2 quartiles of the urethra and for TPR-max and TPR-mode. With the use of the Kappa statistic it was found that the TPR-mode was the most discriminatory of the TPR parameters. Even using this measure, the overlap between normal and GSI was so great as to make accurate diagnosis impossible. It was therefore concluded that TPR analysis is useless for the diagnosis of GSI. However, such an analysis is helpful for the understanding of the pathophysiology of GSI and its treatment.