Study design, materials and methods
This was a pilot cross-sectional study approved by the Institutional Review Board of Inova Health System in Falls Church, Virginia. The study recruited only nulliparous women, divided into two groups; young 18-40y/o (the premenopausal group) and old 52-85y/o (the menopausal group), via Inova Health System Facebook webpage, Inova Health System, Inova Net webpage, Inova Health System “Five-in-Five” emails, and flyers. Participants signed an informed consent before participating the study, the consent document informed participants that this study did not diagnose or treat any injuries/anomalies in any way. Recruitment took place between March 2017 and December 2017. Exclusion criteria included a history of prior incontinence or prolapse surgery, a diagnosis of reproductive anomalies, prior pelvic radiation, or inability to complete written questionnaires. The Two groups completed Pelvic Floor Distress Inventory [PFDI-20], Pelvic Floor Impact Questionnaire [PFIQ-7]), Female Sexual Function Inventory (FSFI-19), a standard urogynecological examination, pelvic floor support assessment using the pelvic organ prolapse quantification system (POP-Q), and a 3-D EVUS. Sonographic measurements included: Minimal Levator Hiatus (MLH), Antero-Posterior diameter (AP) , and Left to Right diameter (LR). We used the mid‐sagittal view to locate the shortest distance between the pubic symphysis and the levator plate, which formed the AP diameter of the MLH. The distance between the levator plate and perineal body was measured using transperineal 2-Dimentional ultrasound both at rest and during Kegel exercise.
Results
A total of 22 women were enrolled in the study divided into 12 young nulliparous group with a mean age of 28.2y/o (95% CI 24.8-31.5), and 10 old nulliparous group with a mean age of 61.8 (95% CI 55.8-67.8). There was no significant difference in height, race, and history of medical illness between the two groups. The younger group had a lower (PFDI-20) score, (mean 3.0, 95% CI: 0.0-9.7 vs. 51.7, 95%CI: 23.6-79.7, p<.001) and lower mean Urinary Distress Inventory (UDI-6) score, (mean .0833 versus 1.1333, p=.002). Simple logistic regression analysis revealed negative correlation between age and sexual activity (92% in the young group vs 60% in the old group (p=0.013), and the PFSI was higher among the young group vs older females. Minimal Levator Hiatus (MLH) as measured by EVUS was not significantly different in the two groups, but the Antero-Posterior diameter (AP) was higher in the older group 45.69mm versus 41.33mm (p=.029), Left to Right (LR) diameter was lower but not statistically significant, and the AP/LR ratio was significantly higher in the older group (1.32 vs 1.41, p<.001).
Interpretation of results
Although the minimal hiatus area does not change significantly by aging, its shape changes into a more oval rather than circular shape. This was demonstrated by a longer AP diameter among the older group and shorter LR diameter ; that resulted in higher AP/LR ratio reflecting the oval shape among the older group. This elongation might lead to poorer function in older nulliparous women and more urinary symptoms. Therefore, young females were found to have less pelvic floor dysfunction-related symptoms (PFDI) and less urinary distress symptoms (UDI-6) compared with old nulliparous women. Moreover, moreover, The young nulliparous women were found to have a better sexual activity and sexual function as indicated by the (FSFI) higher scores compared with the older group.