**Hypothesis/Aims of Study**

To determine the relationship between POP-Q point Aa and maximum urethral straining angle (Q-tip strain) and if the relationship is affected by pelvic organ prolapse in a cohort of women with stress predominant urinary incontinence.

**Study Design. Materials, and Methods**

Maximum urethral straining angles and Aa measurements were obtained from 655 women with stress predominant urinary incontinence and urethral hypermobility who were enrolled in a multicenter randomised surgical trial comparing the retropubic urethropexy and the sling procedures. Respective Institutional Review Boards approved this study. Urethral hypermobility was measured with the Q-tip test, using a goniometer, and was defined by a resting angle or displacement angle at maximum valsalva effort, of >30º from the horizontal plane. Point Aa was measured relative to the hymen in the midline of the anterior vagina with a centimeter ruler with the subject in the supine position, straining maximally. This point of the POP-Q score represents the urethrovesical junction (UVJ). Pearson correlations and linear regression analyses were performed on baseline measures obtained prior to surgery. Q-tip values were treated as continuous variables and point Aa as ordinal data.

**Results**

Subjects had a mean age of 51±10 years and mean BMI of 30±6.5 kg/m2. Seventy three percent were Caucasian, 11% Hispanic and 7% black. The median for point Aa was -1 cm (range –3cm to +3cm ) and the median Q-tipstrain value was 60o (range 10° to 130°). The distribution of point Aa is displayed in Figure 1. The distribution of overall stage of prolapse was 25% stage 0/I, 59% stage II, 16% stage III/IV. Fifteen percent reported prior anterior vaginal or incontinence surgery. Point Aa and Q-tipstrain were weakly correlated (o=0.34, p<0.0001). Results of a linear regression show that as maximum straining angle increases 1 degree, Aa increases 0.026 cm (p<0.0001). When POP-Q stage was held constant in the regression model, as Q-tipstrain increases 1 degree, Aa increases only 0.014 cm (p<0.0001). Therefore, the positive correlation between Aa and Q-tipstrain is not independent of prolapse stage. Age and prior anterior vaginal wall or incontinence surgery had no significant effect on the correlation between Aa and Q-tipstrain (p=0.07, p=0.64 respectively).

**Interpretation of Results**

There is a weak relationship between point Aa and Q-tipstrain angle in this sample of stress incontinent women. As the degree of urethral hypermobility increases, Point Aa becomes more prolapsed. However, one value does not predict the other. Twenty-nine percent of our cohort of stress incontinent women with urethral hypermobility appeared to have good UVJ support by visual inspection, with a point Aa of –2 or above. Our findings suggest that using the criterion of POP-Q point Aa ≥ –1cm to identify women with urethral hypermobility will exclude as many as 31% who meet the standard by Qtip test.

**Concluding Message**

Point Aa of the POP-Q system provides the convenience of a non-instrumented measure of UVJ rotational descent. At values of –1 and more distal, point Aa can serve as a surrogate measure for the Q-tipstrain angle in identifying urethral hypermobility in stress incontinent women. When clinical care has the potential to be influence by the presence or absence of urethral hypermobility, a Q-tip test should be performed in women whose point Aa value is proximal to –1cm.