A holistic view of the effects of episiotomy on pelvic floor

Summary Vaginal delivery is commonly accepted as a risk factor in pelvic floor dysfunction (PFD), however, other obstetric procedures (episiotomy) are still controversial. In this work, to analyze the relationship between episiotomy and pelvic floor function, a finite element model (FEM) of the pelvic cavity is used considering the pelvic floor muscles (PFM) with damaged regions from spontaneous vaginal delivery, and from deliveries with episiotomy. Common features assessed at screening of PFD are evaluated during numerical simulations of both Valsalva maneuver and contraction. As stated in literature, a weakening of the PFM, represented by damaged regions in the FEM, would lead to a bladder neck hypermobility measured as a variation between the alpha angle (angle between the bladder neck and the symphysis pubis line and the midline of the symphysis) during straining and withholding. However, the present work does not associate bladder neck hypermobility to a more damaged muscle, suggesting that other supportive structures also play an important role in the stabilization of the pelvic organs. Furthermore, considering passive behavior of the PFM, independently of the amount of damage considered, the resultant displacements of the pelvic structures are the same. Regarding the PFM contraction, the less the muscle is damaged, the greater the movements of the pelvic organs. Furthermore, the internal organs of the female genital system are the most affected by the unhealthy of the PFM. Additionally, the present study shows that the muscle damage affects more the active muscle component than the passive.