Predictive Value of Biomechanical Mapping for Pelvic Organ Prolapse Surgery

OBJECTIVE: This study examined biomechanical changes in pelvic floor after urogynecological surgery. METHODS: This multisite clinical study was designed to explore changes in tissue elasticity, pelvic support, and certain functions (contractive strength, muscle relaxation speed, muscle motility) after pelvic organ prolapse (POP) surgery. A biomechanical mapping of the pelvic floor was performed before and 4 to 6 months after the surgery. The biomechanical data for 52 parameters were acquired by vaginal tactile imaging for manually applied deflection pressures to vaginal walls and pelvic muscle contractions. The two-sample t-test (P < 0.05) was used to test the null hypothesis that presurgery data in group 1 (positive parameter change after surgery) and presurgery data in group 2 (negative parameter change after surgery) belonged to the same distribution. RESULTS: A total of 78 subjects with 255 surgical procedures were analyzed across 5 participating clinical sites. All 52 t-tests for group 1 versus group 2 had P value in the range from 4.0 × 10-10 to 4.3 × 10-2 associating all of the 52 parameter changes after surgery with the presurgical conditions. The P value of before and after surgery correlation ranged from 3.7 × 10-18 to 1.6 × 10-2 for 50 of 52 tests, with Pearson correlation coefficient ranging from -0.79 to -0.27. Thus, vaginal tactile imaging parameters strongly correlated weak pelvic floor presurgery with the positive POP surgery outcome of improved biomechanical properties. CONCLUSIONS: Pelvic organ prolapse surgery, in general, improves the biomechanical conditions and integrity of the weak pelvic floor. The proposed biomechanical parameters can predict changes resulting from POP surgery.