Introduction and hypothesis: The objective of the study was to compare anterior compartment compliance between women with and without pelvic organ prolapse and to explore factors determining the extent of anterior compartment prolapse.
Methods: Ten women with normal pelvic support and nine with anterior compartment prolapse were analyzed. Abdominal pressure was measured during Valsalva and simultaneous midsagittal dynamic MR imaging. The distance between the most dependent anterior vaginal wall point and a previously determined average nulliparous anterior vaginal wall point was measured. A best-fit line was determined when anterior vaginal wall displacement was plotted relative to abdominal pressure. The slope of this line is a measure of anterior compartment compliance. Multivariate analyses and t tests were performed.
Results: Mean compliance (centimeters per centimeter of water) was higher for cases [0.05 +/- 0.006 standard error of the mean (SEM)] than controls (0.03 +/- .007, p = 0.039). Degree of anterior compartment prolapse correlated best with compliance (R (2) = 0.75, p < 0.01) and also with resting anterior vaginal wall point (R (2) = 0.55, p < 0.01).
Conclusions: Women with anterior compartment prolapse have a 67% more compliant support system compared with those with normal support. Both compliance and resting anterior vaginal wall location are predictors of the degree of anterior compartment prolapse.