Intra-abdominal pressure measurement during ultrasound assessment of women with stress urinary incontinence: a novel model

Abstract

PURPOSE: To determine the influence of intra-abdominal pressure on the ultrasonographic evaluation of the urethrovesical junction (UVJ) and proximal urethra (PU) in women with stress urinary incontinence (SUI). METHODS: This is a prospective cross-sectional study undertaken at the Urinary Incontinence Research Unit (UIRU) of the Universidade Federal de Pernambuco (UFPE). Thirty-six women complaining of SUI underwent perineal ultrasound assessments of the UVJ and PU having the bladder barely empty (< 50 ml of urine) with simultaneous measurement of the intra-abdominal pressure (IAP). An ALOKA ultrasound machine with a 7 MHz vaginal probe was used for the assessments. In order to measure the IAP, an Uromaster MPX616 urodynamic equipment, connected to a 10Fr rectal catheter with a pressure sensitive baloon, was used. RESULTS: The participants' mean age was 46.4 ± 10.2 years. On maximum straining, the mean IAP was 99.3 ± 51.8 cmH(2)0, varying from 7 to 193 cmH(2)0, and the median was 99.5 cmH(2)0. Twenty-eight of 31 patients with UVJ hypermobility (90.3%) easily showed it with an IAP over 40 cmH(2)0. There was no significant association between the mean IAP measurements on maximum straining and the parameters studied. The IAP did induce a significant elongation of the proximal urethra length over 14 mm up to a cut-off over 80 cmH2O, most likely to increase urethral resistance and pressure profile, thus avoiding urine leakage. However, all 19 women with such a characteristic already presented so with an IAP > 40 cmH2O. CONCLUSION: There is no need to measure IAP routinely on perineal ultrasound assessments of the UVJ and PU in women with SUI having a barely empty bladder.