Creation of the biomechanical finite element model of female pelvic floor supporting structure based on thin-sectional high-resolution anatomical images

Abstract

The main purpose of this study is to obtain a finite element biomechanical model that accurately mimics pelvic organ prolapse in women, to study pelvic floor supporting structures' biomechanical properties and function. We used thin-sectional high-resolution anatomical images (Chinese Visible Human, CVH) to reconstruct a detailed three-dimensional (3D) biomechanical finite element model of the female pelvic floor supporting structure including cardinal ligament, uterosacral ligament, levator ani muscle (LAM) and perianal body. The Valsalva maneuver was simulated by loading the uterus and bladder with a pressure increasing from 0 to 10 kPa. The stress, strain and displacement of supporting structures were calculated. The cardinal ligament, the uterosacral ligament and the LAM were stressed greatly when the uterus moved downward, and the maximum stress could reach 0.267 MPa, 1.51 MPa and 0.065 MPa respectively, and the maximum strain could reach 0.154, 0.16, 0.265, and the maximum displacement could reach 1.786 cm, 1.946 cm and 0.567 cm. Displacement of the perineal body also occurred, and its stress, strain and displacement were 0.092 MPa, 0.381, 0.73 cm. The stress, strain and displacement of the supporting structure around the urethra were 0.339 MPa, 0.169, 1.491 cm. Our model based on CVH has more detailed anatomical structures, which is superior to that based on MRI. Our simulation results were consistent with previous findings, which verified the unbalance of abdominal pressure and pelvic floor supporting structures will lead to POP, which provide a theoretical basis for pelvic floor anatomy and function as well as obstetrical surgery.

Keywords: Biomechanics; Chinese Visible Human; Finite element analysis; Levator ani muscle; Prolapse.