Introduction and hypothesis: The purpose of this study was to analyze the histomorphometric properties of the vaginal wall in women with pelvic organ prolapse (POP).
Methods: In 15 women undergoing surgery for POP, full-thickness biopsies were collected at two different sites of location from the anterior and/or posterior vaginal wall. Properties of the precervical area (POP-Q point C/D) were compared with the most distal portion of the vaginal wall (POP-Q point Ba/Bp) using histological staining and immunohistochemistry. The densities of total collagen fibers, elastic fibers, smooth muscle cells, and blood vessels were determined by combining high-resolution virtual imaging and computer-assisted digital image analysis.
Results: The mean elastin density was significantly decreased in the lamina propria and muscularis layer of the vaginal wall from the most distal portion of the prolapsed vaginal wall compared with the precervical area. This difference was statistically significant in the lamina propria for both anterior (8.4 ± 1.2 and 12.1 ± 2.0, p = 0.048) and posterior (6.8 ± 0.5 and 10.1 ± 1.4, p = 0.040) locations, and in the muscularis for the anterior (5.2 ± 0.4 and 8.4 ± 1.2, p = 0.009) vaginal wall. There were no statistically significant differences in the mean densities of collagen fibers, smooth muscle cells or blood vessels between the two locations.
Conclusions: In this study, we observed changes in elastin density in two different locations of the vaginal wall from women with POP. The histomorphometric properties of the vaginal wall can be variable from one place to another in the same patient. This result supports the existence of most vulnerable locations within the vaginal wall and the potential benefit of site-specific prolapse surgery.