Is urethral mobility really being assessed by the pelvic organ prolapse quantification (POP-Q) system?
OBJECTIVE
To estimate the relationship between Q-tip measurement of urethral hypermobility and visual assessment of the urethrovesical junction as assessed by points Aa and Ba of the pelvic organ prolapse quantification (POP-Q) system.


METHODS
A total of 274 patients with pelvic organ prolapse or urinary incontinence had preoperative Q-tip test straining angles and POP-Q staging measurements. By the Q-tip test, urethral hypermobility was defined as a straining angle of 30 degrees or greater relative to the horizontal. As defined in the POP-Q system, point Aa is located in the midline of the anterior vaginal wall 3 cm from the external urethral meatus and represents the urethrovesical junction. Point Ba represents the most dependent position of the anterior vaginal wall. The correlation between point Aa of the POP-Q system and the Q-tip test was assessed using the Spearman correlation coefficient. Similar assessments were made for point Ba.


RESULTS
Mean age of the 274 subjects was 58.5 +/- 11.8 years; mean parity was 3.1 +/- 1.6. A total of 104 patients reported prior surgery for prolapse or incontinence. Mean Q-tip straining angle was 61 +/- 20 degrees; 258 (94%) had urethral hypermobility. Values of point Aa ranged from -3 cm to +3 cm, with median 0 cm. The correlation coefficient between the Q-tip straining angle and point Aa was r = 0.47 (P <.001). Urethral hypermobility was observed in 95% of patients with stage II prolapse at point Aa and in 100% of patients with stages III and IV prolapse at point Aa. The correlation coefficient between the Q-tip straining angle and point Ba was r = 0.32 (P <.001).


CONCLUSIONS
Although the correlation between the Q-tip straining angle and point Aa of the POP-Q was moderately strong, one value cannot be predicted from the other. The Q-tip test may be unnecessary in patients with stages II, III, and IV prolapse at point Aa as virtually all such patients demonstrate urethral hypermobility.
Cogan
Stephanie L
SL
Department of Gynecology and Obstetrics, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA. cogans@ccf.org
Weber
Anne M
AM
Hammel
Jeffrey P
JP
D005260:Female; D006801:Humans; D008875:Middle Aged; D018579:Patient Selection; D017773:Pelvic Floor; D010808:Physical Examination; D014521:Urethra / Q000503:physiopathology*; D014549:Urinary Incontinence / Q000175:diagnosis* / Q000503:physiopathology; D014596:Uterine Prolapse / Q000175:diagnosis* / Q000503:physiopathology