Finite element model focused on stress distribution in the levator ani muscle during vaginal delivery

Krofta, Ladislav; Havelková, Linda; Urbánková, Iva; Krčmář, Michal; Hynčík, Luděk; Feyereisl, Jaroslav

doi:10.1007/s00192-016-3126-1

Cited by 22 publications

(31 citation statements)

References 26 publications

(47 reference statements)

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“…The maximal stress values in the PVm complex were generated during fetal head extension. The obtained value of 44.53 MPa is also comparable to the literature [16]. Finally, the maximum value in the posteromedial inner area of the PRm was 32.55 MPa at station +4, corresponding with data from [13].…”

Section: Discussionsupporting

confidence: 88%

“…Nevertheless, the model was well validated comparing the results of the OA head position with the published data. The maximal mean stress in the ICm was 15.09 MPa, which corresponds to the results in the literature [16,29]. The maximal stress values in the PVm complex were generated during fetal head extension.…”

Section: Discussionsupporting

confidence: 86%

“…The volunteer/legal representative gave written consent. Our method of obtaining the three-dimensional computer model and the imaging protocol have been published previously [16]. The objective of this study was to simulate changes in the LAM during vaginal delivery with respect to the cardinal movements of labor.…”

Section: Methodsmentioning

confidence: 99%

“…The fetal head was also replaced by a rigid body without any possibility to be deformed [16]. For station, following obstetric convention, the pelvis was divided above and below the ischial spine into levels (expressed in centimeters).…”

Section: Initial and Boundary Conditionsmentioning

confidence: 99%

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Persistent occiput posterior position and stress distribution in levator ani muscle during vaginal delivery computed by a finite element model

et al. 2019

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Introduction and hypothesis Objective of this study was to develop an MRI-based finite element model and simulate a childbirth considering the fetal head position in a persistent occiput posterior position. Methods The model involves the pelvis, fetal head and soft tissues including the levator ani and obturator muscles simulated by the hyperelastic nonlinear Ogden material model. The uniaxial test was measured using pig samples of the levator to determine the material constants. Vaginal deliveries considering two positions of the fetal head were simulated: persistent occiput posterior position and uncomplicated occiput anterior position. The von Mises stress distribution was analyzed. Results The material constants of the hyperelastic Ogden model were measured for the samples of pig levator ani. The mean values of Ogden parameters were calculated as: μ1 = 8.2 ± 8.9 GPa; μ2 = 21.6 ± 17.3 GPa; α1 = 0.1803 ± 0.1299; α2 = 15.112 ± 3.1704. The results show the significant increase of the von Mises stress in the levator muscle for the case of a persistent occiput posterior position. For the optimal head position, the maximum stress was found in the anteromedial levator portion at station +8 (mean: 44.53 MPa). For the persistent occiput posterior position, the maximum was detected in the distal posteromedial levator portion at station +6 (mean: 120.28 MPa). Conclusions The fetal head position during vaginal delivery significantly affects the stress distribution in the levator muscle. Considering the persistent occiput posterior position, the stress increases evenly 3.6 times compared with the optimal head position.

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Section: Discussionsupporting

confidence: 88%

Section: Discussionsupporting

confidence: 86%

Section: Methodsmentioning

confidence: 99%

Section: Initial and Boundary Conditionsmentioning

confidence: 99%

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Persistent occiput posterior position and stress distribution in levator ani muscle during vaginal delivery computed by a finite element model

et al. 2019

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“…The puborectalis muscle is required to be stretched during delivery to more than three times its original length. This stretching is over twice what the striated muscle can endure without injury in a nonpregnant female [3]. Therefore, levator ani muscle (LAM) injuries occur in 13-36% of women following vaginal childbirth [4].…”

Section: Introductionmentioning

confidence: 99%

MRI comparative study of levator ani muscle changes in nulliparous and multiparous females

Azzam

Halim

El-Assaly

et al. 2019

Egypt J Radiol Nucl Med

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Background: Pelvic floor dysfunction is known to be among the principal factors influencing public health, regarding frequency, cost and effect on women's quality of life. Radiographic assessment of the pelvic floor function and anatomy plays a vital role in the recognition of pelvic floor defects. The aim of this study is to detect the postpartum-related levator ani muscle changes thus defining the relationship between the vaginal deliveries and the etiology of pelvic floor dysfunction in order to provide guidelines to decrease the incidence of pelvic floor injuries during parturition and guide the treatment plan. Results: There was a significant difference in the puborectalis muscle thickness between the case and control groups in the right puborectalis (P value ≤ 0.001) and in the left puborectalis (P value (≤ 0.001) as well as significant midpoint thickness (P value = 0.03) with 46.2% puborectalis muscle injury in the case group compared with none in the control group. Conclusion: Pelvic floor MRI is highly recommended as it is a contrast-free modality that allows for both anatomical and functional analysis. Its incorporation in the routine postpartum assessment will allow early detection of abnormalities even in asymptomatic cases thus ensuring proper management and preventing the development of pelvic floor dysfunction predisposed to by repeated vaginal deliveries.

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In vivo evaluation of the levator ani muscle in primiparous women using diffusion tensor imaging and fiber tractography

Cui

Zhao

Cui

et al. 2021

Intl J Gynecology & Obste

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Objective To characterize the levator ani muscle (LAM) injury after first vaginal delivery and investigate the clinical application of diffusion tensor imaging (DTI) and fiber tractography in evaluating the LAM. Methods Fifty‐eight primiparous women at 6 weeks after vaginal delivery and 27 nulliparous women as controls underwent T2‐weighted sequence and DTI sequence of the pelvic floor. A LAM scoring system was used to characterize the morphological changes. Fiber tractography of each major subdivision of LAM was performed, followed by assessment of the quality of fiber tracking. Fractional anisotropy (FA), apparent diffusion coefficient (ADC), fiber volume, and length were calculated. Results Puborectalis and iliococcygeus injuries were observed in 30/58 (51.7%) and 10/58 (17.2%) primiparae, respectively. No LAM defects were identified in the control group. For the puborectalis, the FA values were lower (P = 0.010) and ADC values were higher (P = 0.024) in the primiparous group than in the control group. For the iliococcygeus, the fiber volume values were lower in the primiparous group than in the control group (P = 0.004). Conclusion Vaginal delivery can result in LAM injury at the puborectalis. DTI parameters can assist in the quantitative diagnosis of the LAM injury.

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Finite element model focused on stress distribution in the levator ani muscle during vaginal delivery

Cited by 22 publications

References 26 publications

Persistent occiput posterior position and stress distribution in levator ani muscle during vaginal delivery computed by a finite element model

Persistent occiput posterior position and stress distribution in levator ani muscle during vaginal delivery computed by a finite element model

MRI comparative study of levator ani muscle changes in nulliparous and multiparous females

In vivo evaluation of the levator ani muscle in primiparous women using diffusion tensor imaging and fiber tractography

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