Introital ultrasonography:: a comparison of women with stress incontinence due to urethral hypermobility and continent women

OBJECTIVE To determine if there is a variable on introital ultrasonography (IUS) that can be used to distinguish between women with stress urinary incontinence (SUI) due to urethral hypermobility (UH) and continent women. PATIENTS AND METHODS This single-centre, prospective, blind, cohort, observational study comprised 383 women (245 continent and 138 incontinent) who were all appropriately informed volunteers selected according to the inclusion criteria. IUS with a convex probe was performed on all women; the measurement plane was standardized and coordinates were obtained at rest and on straining. Several distances were measured to determine if any provided an objective distinction between continent and incontinent women. RESULTS Among all the IUS variables assessed, sliding (calculated as the difference between the distance urethra-bladder neck, U-BN, at rest and under stress) was the best for distinguishing continent and incontinent women. The receiver operating characteristic curves showed that with a threshold of 8 mm, sliding had a sensitivity of 92% and a specificity of 79.6% for detecting SUI due to UH. The distances symphysis-urethra (S-U) and U-BN at rest could also discriminate, but with lower significance. CONCLUSIONS IUS is an important tool for diagnosing SUI; there are three independent variables, one dynamic (sliding) and two static (distances S-U and U-BN), that can be used to distinguish between continent women and those with SUI due to UH. Sliding is the most reliable, as it has the highest sensitivity and specificity. We think that the simplicity, low financial cost and reliability of IUS could allow it to be a routine procedure for physicians working in incontinence units.