Relationship between Q-Tip Test and Urethral Hypermobility on Perineal Ultrasound

Background: The aim of this study was to assess the correlation between the overall rest–stress distance measured by transperineal ultrasound (TPUS) and Q-tip test angle in women with urodynamic stress incontinence (USI), and determine a cut-off value of rest–stress distance for predicting urethral hypermobility (UH). Methods: Women with USI scheduled for mid-urethral sling surgery were retrospectively recruited. UH was defined as a Q-tip angle more than or equal to 30 degrees. Ultrasonic measurement of the overall rest–stress distance was defined as the linear distance of bladder-neck position change from resting status to maximal strain. Results: Among the 132 enrolled women, the Pearson correlation coefficient between the overall rest–stress distance in TPUS and Q-tip test angle was 0.9104 (95% CI, 0.8758–0.9357, p < 0.001). In receiver-operating-characteristic-curve analysis, a rest–stress distance of more than 13.3 mm was an optimal cut-off value to predict UH (sensitivity = 76.47%, specificity = 93.3%; area = 0.937, 95% confidence interval: 0.881–0.972). Conclusions: The overall rest–stress distance in TPUS correlated well with the Q-tip test angle, indicating that it can be an alternative method for the assessment of USI. A rest–stress distance of more than 13.3 mm was an optimal cut-off value to predict UH in women with USI.