Retrograde urethral sphincterometry

2.1.1 Stress urinary incontinence is the involuntary leakage of urine during exercise or certain movements such as coughing, sneezing and laughing. It is usually caused by weak or damaged muscles and connective tissues in the pelvic floor and urethral sphincter.

2.1.2 Diagnosis of stress urinary incontinence is usually based on symptoms, examination and exclusion of underlying causes or comorbidity.

2.1.3 Retrograde urethral sphincterometry measures the pressure needed to open, and just keep open, a closed urethra by the retrograde infusion of fluid. This has been proposed as an assessment of urethral function in women with symptoms of stress urinary incontinence.

2.1.4 Established tests of urethral function include urethral pressure profilometry (UPP) and valsalva leak point pressure. Radiographic assessment of urethral function can be done using videocystourethrography.

2.2.1 Retrograde urethral sphincterometry (RUS) involves placing a cone-shaped device a short distance (about 5 mm) into the external urethral meatus. The device then infuses fluid at a controlled rate into the urethra. The pressure required to open the urethral sphincter is displayed on the device.

2.3.1 Preliminary data on the use of this procedure in women with stress urinary incontinence found that there was a weak relationship between the results of this test and other standard tests. In a trial of 258 symptomatic women the mean retrograde urethral pressure as measured by RUS was 71 cm H₂O, and the mean values were reported as decreasing with increasing symptom severity. In another study, the mean retrograde urethral pressure was found to be 112.6 cm H₂O in 61 asymptomatic women.

2.3.2 The impact of this procedure on patient outcomes is currently unclear. For more details, refer to the Sources of evidence.

2.3.3 The Specialist Advisors noted that efficacy outcomes are yet to be established.

2.4.1 In a study of 258 women, pain (2%) and dysuria (2%) were the two most commonly reported complaints. A total of 12 adverse events were noted in a study of 61 asymptomatic women who had RUS; these included lower back pain (2%), discomfort (2%), urethral pain (3%), dysuria (3%), urinary urgency (3%), urinary frequency (3%) and transient incontinence (3%). For more details, refer to the Sources of evidence.

2.4.2 The Specialist Advisors noted urinary tract infection and mild discomfort as potential adverse events.