Quantity and distribution of levator ani stretch during simulated vaginal childbirth

Hoyte, Lennox; Damaser, Margot S.; Warfield, Simon K.; Chukkapalli, Giridhar; Majumdar, Amitava; Choi, Dong Ju; Trivedi, Abhishek; Krysl, Petr

doi:10.1016/j.ajog.2008.04.027

Cited by 107 publications

(112 citation statements)

References 18 publications

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“…Biomechanical modelling of the second stage of labour is complicated because it requires detailed morphological descriptions of the pelvic floor structures, with very sparse data [13,14,15]. In this study, we have presented a quantitative modelling framework by integrating available information (e.g.…”

Section: Discussionmentioning

confidence: 99%

Modelling Childbirth: Comparing Athlete and Non-athlete Pelvic Floor Mechanics

Kruger

Chung

et al. 2008

Lecture Notes in Computer Science

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Abstract. There is preliminary evidence that athletes involved in highintensity sports for sustained periods have a higher probability of experiencing a prolonged second stage of labour compared to non-athletes. The mechanisms responsible for these differences are not clear, although it is postulated that muscle hypertrophy and increased muscle tone in athletes may contribute to difficulties in vaginal delivery. In order to test these hypotheses, we have constructed individual-specific finite element models of the female pelvic floor (one athlete and one non-athlete) and the fetal head to simulate vaginal delivery and enable quantitative analysis of the differences. The motion of the fetal head descending through the pelvic floor was modelled using finite deformation elasticity with contact mechanics. The force required to push the head was compared between the models and a 45% increase in peak force was observed in the athlete model compared to the non-athlete. In both cases, the overall maximum stretch was induced at the muscle insertions to the pubis. This is the beginning of a quantitative modelling framework that is intended to help clinicians assess the risk of natural versus caesarean birth by taking into account the possible mechanical response of pelvic floor muscles based on their size and activation patterns prior to labour.

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Section: Discussionmentioning

confidence: 99%

Modelling Childbirth: Comparing Athlete and Non-athlete Pelvic Floor Mechanics

Kruger

Chung

et al. 2008

Lecture Notes in Computer Science

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“…Several studies have used the finite element method (FEM) to simulate LA muscle mechanics (Lien et al 2004;Martins et al 2007;Hoyte et al 2008;Lee et al 2005). Mechanical properties of the LA muscle have been approximated with parameters from other muscular tissues such as the heart (Martins et al 2007), or the facial muscles (Lee et al 2005), due to a sparsity of data on pelvic floor muscles.…”

Section: Introductionmentioning

confidence: 99%

Anisotropic effects of the levator ani muscle during childbirth

Kruger

Nash

et al. 2010

Biomech Model Mechanobiol

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Pelvic floor dysfunction and pelvic organ prolapse have been associated with damage to the levator ani (LA) muscle, but the exact mechanisms linking them remain unknown. It has been postulated that factors such as vaginal birth and ageing may contribute to long-term, irreversible LA muscle damage. To investigate the biomechanical significance of the LA muscle during childbirth, researchers and clinicians have used finite element models to simulate the second stage of labour. One of the challenges is to represent the anisotropic mechanical response of the LA muscle. In this study, we investigated the effects of anisotropy by varying the relative stiffness between the fibre and the matrix components, whilst maintaining the same overall stress-strain response in the fibre direction. A foetal skull was passed through two pelvic floor models, which incorporated the LA muscle with different anisotropy ratios. Results showed a substantial decrease in the magnitude of the force required for delivery as the fibre anisotropy was increased. The anisotropy ratio markedly affected the mechanical response of the LA muscle during a simulated vaginal delivery. It is apparent that we need to obtain experimental data on muscle mechanics in order to better approximate the LA muscle mechanical properties for quantitative analysis. These models may advance our understanding of the injury mechanisms of pelvic floor during childbirth.

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“…Previous work focused on the computational analysis of the pelvic floor muscles during vaginal delivery (Hoyte et al, 2008;Li et al, 2008;Parente et al, 2009b). In those studies, the authors modeled the fetus head as an undeformable structure or having stiff material properties.…”

Section: Introductionmentioning

confidence: 99%