Biomechanical properties of prolapsed vaginal tissue in pre- and postmenopausal women.

The aim of this study was to explore the relationship between biomechanical properties and the occurrence of pelvic organ prolapse (POP) through analysis on biomechanical properties of vaginal tissue. The biopsy specimens were obtained from 43 patients undergoing transvaginal hysterectomy, who were assigned into premenopausal POP, postmenopausal POP, premenopausal control and postmenopausal control groups. Tissue specimens were biomechanically assessed by a purpose-built tissue puller system, and stress-strain curves were digitally recorded. The Young's modulus, Poisson's ratio, maximum elongation, maximum fracture of vaginal tissue were 9.45 +/- 0.70, 0.43 +/- 0.01, 1.50 +/- 0.02, 0.60 +/- 0.02 in premenopausal POP group; 12.10 +/- 1.10, 0.39 +/- 0.01, 1.14 +/- 0.05, 0.27 +/- 0.03 in postmenopausal POP group; 6.65 +/- 1.48, 0.46 +/- 0.01, 1.68 +/- 0.11, 0.79 +/- 0.05 in premenopausal control group and 10.26 +/- 1.10, 0.42 +/- 0.01, 1.37 +/- 0.04, 0.42 +/- 0.03 in postmenopausal control group. There was significant difference in biomechanical properties between premenopausal POP group and premenopausal control group (p < 0.01). There was significant difference in biomechanical properties between postmenopausal POP group and postmenopausal control group (p < 0.01). Biomechanical properties in POP group were significantly lower than that in control group, suggesting that degeneration of biomechanical properties in pelvic support construction might lead to the occurrence of POP.