Biomechanical mapping of the female pelvic floor: changes with age, parity and weight.

Quantitative biomechanical characterization of pelvic supportive structures and functions in vivo is thought to provide insight into the pathophysiology of pelvic floor disorders including pelvic organ prolapse (POP). An innovative approach - vaginal tactile imaging - allows biomechanical mapping of the female pelvic floor to quantify tissue elasticity, pelvic support, and pelvic muscle functions. The objective of this study is to explore an extended set of 52 biomechanical parameters to characterize pelvic floor changes with age, parity, and subject weight for normal pelvic floor conditions. 42 subjects with normal pelvic conditions (no POP, no stress urinary incontinence) were included in the data analysis from an observational, case-controlled study. The Vaginal Tactile Imager (VTI) was used with an analytical software package to automatically calculate 52 biomechanical parameters for 8 VTI test procedures (probe insertion, elevation, rotation, Val-salva maneuver, voluntary muscle contractions in 2 planes, relaxation, and reflex contraction). The ranges, mean values, and standard deviations for all 52 VTI parameters were established. 12 VTI parameters were identified as statistically sen-sitive (p < 0.05; t-test) to the subject age; 9 parameters were identified as statistically sensitive (p < 0.05; t-test) to the subject parity; no sensitivity was found to subject weight. Among the 12 parameters sensitive to women's age, 6 parameters show changes (decrease) in tissue elasticity and 6 parameters show weakness in pelvic muscle functions with age. Among the 9 parameters sensitive to parity, 5 parameters show changes (decrease) in tissue elasticity and 4 parameters show weakness in pelvic muscle functions after giving birth. The biomechanical mapping of the female pelvic floor with the VTI provides a unique set of parameters characterizing pelvic changes with age and parity. These objectively measurable biomechanical transformations of pelvic tissues, support structures, and functions may be used in future research and practical applications.