An approach on determining the displacements of the pelvic floor during voluntary contraction using numerical simulation and MRI

Abstract

The present study was conducted in order to establish a methodology based on the finite element method to simulate the contraction of the pelvic floor (PF) muscles. In the generated finite element model, a downward pressure of 90 cm H₂O was applied, while actively contracting the PF muscles with different degrees of muscular activation (10, 50 and 100%). The finite element methodology of the active contraction behaviour proposed in this study is adequate to simulate PF muscle contraction with different degrees of muscular activation. In this case, in particular, for an activation of 100%, the numerical model was able to displace the pubovisceral muscle in a range of values very similar to the displacement found in the magnetic resonance imaging data. In the analysed case study, it would be possible to conclude that an intensity contraction of 50% would be necessary to produce enough stiffness to avoid possible urine loss.

Keywords:

• finite elements method
• pelvic floor contraction
• stress urinary incontinence

Acknowledgements

This work was partially done under the scope of the following research projects ‘Methodologies to Analyze Organs from Complex Medical Images – Applications to the Female Pelvic Cavity’, ‘Cardiovascular Imaging Modeling and Simulation – SIMCARD’ and ‘Aberrant Crypt Foci and Human Colorectal Polyps: Mathematical Modelling and Endoscopic Image Processing’, with the references PTDC/EEA-CRO/103320/2008, UTAustin/CA/0047/2008 and UTAustin/MAT/0009/2008, respectively, financially supported by FCT – Fundação para a Ciência e a Tecnologia in Portugal.

The authors truly acknowledge the funding provided by CAPES and CNPq from Brazil and Ministério da Ciência, Tecnologia e Ensino Superior, FCT, Portugal (Proc. 4.1.3/CAPES/FCT); as well as the funding by FCT/FEDER under grants PTDC/SAUBEB/71459/2006. The authors also wish to thank Dr Luciana Capanema, Dr Joana Loureiro, Dr Campos Costa and Consultório de Tomografia Computorizada, S.A.