Can urethral mobility be assessed using the pelvic organ prolapse quantification system? An analysis of the correlation between point Aa and Q-tip angle in varying stages of prolapse.

Objectives: To determine whether the Pelvic Organ Prolapse-Quantification (POP-Q) system can be used as a replacement for Q-tip testing to assess urethral mobility in women.

Methods: We performed a retrospective review of a clinical database of 1490 patients presenting to a urogynecology clinic. The evaluation included both Q-tip straining angle and POP-Q examination. Urethral hypermobility was defined by the Q-tip test as a straining angle of 30 degrees or greater relative to the horizontal. The correlation between point Aa of the POP-Q system and the maximal Q-tip straining angle was determined using the Spearman correlation coefficient.

Results: The mean age of the 1490 patients was 59.5 +/- 13.1 years; the median parity was 2. A total of 62 patients (4.2%) reported prior surgery for incontinence or prolapse. The mean Q-tip straining angle was 44.7 degrees +/- 21.8 degrees. The point Aa values were +3 to -3 cm (median -2). The correlation coefficient between the Q-tip straining angle and point Aa was 0.54 (P <0.001). Urethral hypermobility was observed in 93.3% patients with stage 3 prolapse, 92.5% with stage 2, 88.9% with stage 1, and 55.8% with stage 0. Only in patients with stage 4 prolapse was urethral hypermobility observed 100% of the time.

Conclusions: The correlation between point Aa of the POP-Q and the Q-tip straining angle was moderately strong when analyzed across all degrees of prolapse. However, urethral hypermobility could not be reliably predicted from POP-Q measurement alone. Therefore, the Q-tip test remains an essential part of the urogynecologic evaluation.