In vivo assessment of the elastic properties of women's pelvic floor during pregnancy using shear wave elastography: design and protocol of the ELASTOPELV study

Bertrand Gachon, Xavier Fritel, Fabrice Pierre, Antoine Nordez, Bertrand Gachon, Xavier Fritel, Fabrice Pierre, Antoine Nordez

Abstract

Background: Animal studies have reported an increase in pelvic floor muscle stiffness during pregnancy, which might be a protective process against perineal trauma at delivery. Our main objective is to describe the changes in the elastic properties of the pelvic floor muscles (levator ani, external anal sphincter) during human pregnancy using shear wave elastography (SWE) technology. Secondary objectives are as follows: i) to look for specific changes of the pelvic floor muscles compared to peripheral muscles; ii) to determine whether an association between the elastic properties of the levator ani and perineal clinical and B-mode ultrasound measures exists; and iii) to provide explorative data about an association between pelvic floor muscle characteristics and the risk of perineal tears.

Methods: Our prospective monocentric study will involve three visits (14-18, 24-28, and 34-38 weeks of pregnancy) and include nulliparous women older than 18 years, with a normal pregnancy and a body mass index (BMI) lower than 35 kg.m- 2. Each visit will consist of a clinical pelvic floor assessment (using the Pelvic Organ Prolapse Quantification system), an ultrasound perineal measure of the anteroposterior hiatal diameter and SWE assessment of the levator ani and the external anal sphincter muscles (at rest, during the Valsalva maneuver and during pelvic floor contraction), and SWE assessment of both the biceps brachii and the gastrocnemius medialis (at rest, extension and contraction). We will collect data about the mode of delivery and the occurrence of perineal tears. We will investigate changes in continuous variables collected using the Friedman test. We will look for an association between the elastic properties of the levator ani muscle and clinical / ultrasound measures using a Spearman test at each trimester. We will investigate the association between the elastic properties of the pelvic floor muscles and perineal tear occurrence using a multivariate analysis with logistic regression.

Discussion: This study will provide original in vivo human data about the biomechanical changes of pregnant women's pelvic floor. The results may lead to an individualized risk assessment of perineal trauma at childbirth.

Trial registration: This study was registered on https://ichgcp.net/clinical-trials-registry/NCT03602196" title="See in ClinicalTrials.gov">NCT03602196).

Keywords: Anal sphincter; Childbirth; Levator ani muscle; Obstetric anal sphincter injury; Perineal trauma; Pregnancy; Shear wave elastography.

Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Fig. 1
Fig. 1
ELASTOPELV study design, inclusion criteria and data collected
Fig. 2
Fig. 2
Levator ani muscle SWE assessment: probe position and example of acquisition
Fig. 3
Fig. 3
External anal sphincter SWE assessment: probe position and example of acquisition
Fig. 4
Fig. 4
SWE acquisitions of the biceps brachii muscle at rest and standardized extension
Fig. 5
Fig. 5
SWE acquisitions of the gastrocnemius medialis muscle at rest and standardized extension

References

    1. Fritel X, Gachon B, Desseauve D, et al. Anal incontinence and obstetrical anal sphincter injuries, epidemiology and prevention. Gynecol Obstet Fertil Senol. 2018;46:419–426.
    1. Gachon B, Nordez A, Pierre F, et al. Tissue biomechanical behavior should be considered in the risk assessment of perineal trauma at childbirth. Arch Gynecol Obstet. 2019;300:1821–1826.
    1. Van Delft K, Sultan AH, Thakar R, et al. The relationship between postpartum levator ani muscle avulsion and signs and symptoms of pelvic floor dysfunction. BJOG. 2014;121:1164–1171.
    1. Van Delft K, Thakar R, Sultan AH, et al. Does the prevalence of levator ani muscle avulsion differ when assessed using tomographic ultrasound imaging at rest vs on maximum pelvic floor muscle contraction? Ultrasound Obstet Gynecol. 2015;46:99–103.
    1. Ashton-Miller JA, DeLancey JO. Functional anatomy of the female pelvic floor. Ann N Y Acad Sci. 2007;1101:266–296.
    1. Meriwether KV, Rogers RG, Dunivan GC, et al. Perineal body stretch during labor does not predict perineal laceration, postpartum incontinence, or postpartum sexual function: a cohort study. Int Urogynecol J. 2016;27:1193–1200.
    1. Knoepp LR, McDermott KC, Munoz A. Joint hypermobility, obstetrical outcomes, and pelvic floor disorders. Int Urogynecol J. 2013;24:735–740.
    1. Gachon B, Desgranges M, Fradet L, et al. Is increased peripheral ligamentous laxity in term pregnant women associated with obstetric anal sphincter injury? Int Urogynecol J. 2018;29:1589–1595.
    1. Alperin M, Kaddis T, Pichika R, et al. Pregnancy-induced adaptations in intramuscular extracellular matrix of rat pelvic floor muscles. Am J Obstet Gynecol. 2016;215:210.e1–210.e7.
    1. Alperin M, Lawley DM, Esparza MC, et al. Pregnancy-induced adaptations in the intrinsic structure of rat pelvic floor muscles. Am J Obstet Gynecol. 2015;213:e191–e197.
    1. Catanzarite T, Bremner S, Barlow CL, et al. Pelvic muscles’ mechanical response to strains in the absence and presence of pregnancy-induced adaptations in a rat model. Am J Obstet Gynecol. 2018;218:512e1–512.e9.
    1. LaCroix AS, Duenwald-Kuehl SE. Lakes RS and al. Relationship between tendon stiffness and failure: a metaanalysis. J Appl Physiol. 2013;115:43–51.
    1. Gachon B, Nordez A, Pierre F, et al. In vivo assessment of the levator ani muscles using shear wave elastography: a feasibility study in women. Int Urogynecol J. 2019;30:1179–1186.
    1. Kruger JA, Nielsen PM, Budgett SC, et al. An automated hand-held elastometer for quantifying the passive stiffness of the levator ani muscle in women. Neurourol Urodyn. 2015;34:133–138.
    1. Hug F, Tucker K, Gennisson JL, et al. Elastography for muscle biomechanics: toward the estimation of individual muscle force. Exerc Sport Sci Rev. 2015;43:125–133.
    1. Ashton-Miller JA, Delancey JO. On the biomechanics of vaginal birth and common sequelae. Annu Rev Biomed Eng. 2009;11:163–176.
    1. Gachon B, Fritel X, Fradet L, et al. Is levator hiatus distension associated with peripheral ligamentous laxity during pregnancy? Int Urogynecol J. 2017;28:1223–1231.
    1. Marnach ML, Ramin KD, Ramsey PS, et al. Characterization of the relationship between joint laxity and maternal hormones in pregnancy. Obstet Gynecol. 2003;101:331–335.
    1. Schauberger CW, Rooney BL, Goldsmith L, et al. Peripheral joint laxity increases in pregnancy but does not correlate with serum relaxin levels. Am J Obstet Gynecol. 1996;174:667–671.
    1. Gennisson JL, Deffieux T, Fink M, et al. Ultrasound elastography: principles and techniques. Diagn Interv Imaging. 2013;94:487–495.
    1. Bercoff J, Tanter M. Fink M supersonic shear imaging: a new technique for soft tissue elasticity mapping. IEEE Trans Ultrason Ferroelectr Freq Control. 2004;51:396–409.
    1. Royer D, Gennisson JL, Deffieux T, et al. On the elasticity of transverse isotropic soft tissues. J Acoust Soc Am. 2011;129:2757–2760.
    1. Eby SF, Song P, Chen S, et al. Validation of shear wave elastography in skeletal muscle. J Biomech. 2013;46:2381–2387.
    1. Taljanovic MS, Gimber LH, Becker GW, et al. Shear-wave Elastography: basic physics and musculoskeletal applications. Radiographics. 2017;37:855–870.
    1. Lacourpaille L, Hug F, Bouillard K, et al. Supersonic shear imaging provides a reliable measurement of resting muscle shear elastic modulus. Physiol Meas. 2012;33:19–28.
    1. Gennisson JL, Muller M, Gabor P, et al. Quantification of elasticity changes in the myometrium during labor using supersonic shear imaging: a feasibility study. Ultrasonics. 2015;56:183–188.
    1. Mottet N, Metz JP, Chaussy Y. Evolution of fetal lung stiffness during gestation in two different congenital malformations. J Obstet Gynaecol Res. 2019;45:931–934.
    1. Bump RC, Mattiasson A, Bo K, et al. The standardization of terminology of female pelvic organ prolapse and pelvic floor dysfunction. Am J Obstet Gynecol. 1996;175:10–17.
    1. Dietz HP. Pelvic floor ultrasound: a review. Am J Obstet Gynecol. 2010;202:321–334.
    1. Dietz HP, Shek C, Clarke B. Biometry of the pubovisceral muscle and levator hiatus by three-dimensional pelvic floor ultrasound. Ultrasound Obstet Gynecol. 2005;25:580–585.
    1. Orno AK, Dietz HP. Levator co-activation is a significant confounder of pelvic organ descent on Valsalva maneuver. Ultrasound Obstet Gynecol. 2007;30:346–350.
    1. Dietz HP, Shek KL. Levator defects can be detected by 2D translabial ultrasound. Int Urogynecol J Pelvic Floor Dysfunct. 2009;20:807–811.
    1. Dietz HP. Exoanal imaging of the anal sphincters. J Ultrasound Med. 2018;37:263–280.
    1. Lacourpaille L, Nordez A, Hug F, et al. Time-course effect of exercise-induced muscle damage on localized muscle mechanical properties assessed using elastography. Acta Physiol. 2014;211:135–146.
    1. Royal College of Obstetricians and Gynaecologists. Green-top Guideline No. 29. The management of third- and fourth-degree perineal tears 2015. Last consultation on the 10/02/2020.
    1. Ducarme G, Pizzoferrato AC, de Tayrac R, et al. Perineal prevention and protection in obstetrics: CNGOF clinical practice guidelines. J Gynecol Obstet Hum Reprod. 2018;48:455–460.
    1. Kruger JA, Budgett SC, Wong V, et al. Characterising levator-ani muscle stiffness pre- and post-childbirth in European and Polynesian women in New Zealand: a pilot study. Acta Obstet Gynecol Scand. 2017;96:1234–1242.
    1. Egorov V, van Raalte H, Sarvazyan AP. Vaginal tactile imaging. IEEE Trans Biomed Eng. 2010;57:1736–1744.
    1. Van Raalte H, Egorov V. Characterizing female pelvic floor conditions by tactile imaging. Int Urogynecol J. 2015;26:607–609.
    1. Chen L, Low LK, DeLancey JO, et al. In vivo estimation of perineal body properties using ultrasound quasistatic elastography in nulliparous women. J Biomech. 2015;48:1575.
    1. Kreutzkamp JM, Schäfer SD, Amler S, et al. Strain elastography as a new method for assessing pelvic floor biomechanics. Ultrasound Med Biol. 2017;43:868–872.
    1. Xie M, Zhang X, Zhang X, et al. Can we evaluate the levator ani after Kegel exercise in women with pelvic organ prolapse by transperineal elastography? A preliminary study. J Med Ultrason. 2018;45:437–441.
    1. Masslo K, Mollers M, De Murcia KO, et al. New method for assessment of levator avulsion injury: a comparative elastography study. J Ultrasound Med. 2018. 10.1002/jum.14810.
    1. De Freitas SS, Cabral AL. De Melo Costa pinto R et al. effects of perineal preparation techniques on tissue extensibility and muscle strength: a pilot study. Int Urogynecol J. 2019;30:951–957.
    1. Paschoal A, Zanetti MRD, Petricelli CD, et al. Quantitative assessment of pelvic floor muscle extensibility in pregnant women with a perineal elasticity meter. J Matern Fetal Neonatal Med. 2019;27:1–5.
    1. Dietz HP, Shek C, De Leon J, et al. Ballooning of the levator hiatus. Ultrasound Obstet Gynecol. 2008;31:676–680.
    1. Oliveira DA, Parente MP, Calvo B, et al. A biomechanical analysis on the impact of episiotomy during childbirth. Biomech Model Mechanobiol. 2016;15:1523–1534.

Source: PubMed

Sponsorit ja yhteistyökumppanit

Sairaudet

Huumeiden interventiot

3
Tilaa