Dynamic Magnetic Resonance Imaging and pelvic floor disorders: how and when?

Pelvic organ movements in asymptomatic nulliparous and symptomatic premenopausal women with pelvic organ prolapse in dynamic MRI: a feasibility study comparing midsagittal single-slice with multi-slice sequences

PURPOSE

To compare multi-slice (MS) MRI sequences of the pelvis acquired at rest and straining to dynamic midsagittal single-slice (SS) sequences for the assessment of pelvic organ prolapse (POP).

METHODS

This IRB-approved prospective single-center feasibility study included 23 premenopausal symptomatic patients with POP and 22 asymptomatic nulliparous volunteers. MRI of the pelvis at rest and straining was performed with midsagittal SS and MS sequences. Straining effort, visibility of organs and POP grade were scored on both. Organ points (bladder, cervix, anorectum) were measured. Differences between SS and MS sequences were compared with Wilcoxon test.

RESULTS

Straining effort was good in 84.4% on SS and in 64.4% on MS sequences (p = 0.003). Organ points were always visible on MS sequences, whereas the cervix was not fully visible in 31.1-33.3% on SS sequences. At rest, there were no statistically significant differences of organ point measurements between SS and MS sequences in symptomatic patients. At straining, positions of bladder, cervix, and anorectum were + 1.1 cm (± 1.8 cm), - 0.7 cm (± 2.9 cm), and + 0.7 cm (± 1.3 cm) on SS and + 0.4 mm (± 1.7 cm), - 1.4 cm (± 2.6 cm), and + 0.4 cm (± 1.3 cm) on MS sequences (p < 0.05). Only 2 cases of higher-grade POP were missed on MS sequences (both with poor straining effort).

CONCLUSION

MS sequences increase the visibility of organ points compared to SS sequences. Dynamic MS sequences can depict POP if images are acquired with sufficient straining effort. Further work is needed to optimize the depiction of the maximum straining effort with MS sequences.

Imaging modalities for the detection of posterior pelvic floor disorders in women with obstructed defaecation syndrome

BACKGROUND

Obstructed defaecation syndrome (ODS) is difficulty in evacuating stools, requiring straining efforts at defaecation, having the sensation of incomplete evacuation, or the need to manually assist defaecation. This is due to a physical blockage of the faecal stream during defaecation attempts, caused by rectocele, enterocele, intussusception, anismus or pelvic floor descent. Evacuation proctography (EP) is the most common imaging technique for diagnosis of posterior pelvic floor disorders. It has been regarded as the reference standard because of extensive experience, although it has been proven not to have perfect accuracy. Moreover, EP is invasive, embarrassing and uses ionising radiation. Alternative imaging techniques addressing these issues have been developed and assessed for their accuracy. Because of varying results, leading to a lack of consensus, a systematic review and meta-analysis of the literature are required.

OBJECTIVES

To determine the diagnostic test accuracy of EP, dynamic magnetic resonance imaging (MRI) and pelvic floor ultrasound for the detection of posterior pelvic floor disorders in women with ODS, using latent class analysis in the absence of a reference standard, and to assess whether MRI or ultrasound could replace EP. The secondary objective was to investigate differences in diagnostic test accuracy in relation to the use of rectal contrast, evacuation phase, patient position and cut-off values, which could influence test outcome.

SEARCH METHODS

We ran an electronic search on 18 December 2019 in the Cochrane Library, MEDLINE, Embase, SCI, CINAHL and CPCI. Reference list, Google scholar. We also searched WHO ICTRP and clinicaltrials.gov for eligible articles. Two review authors conducted title and abstract screening and full-text assessment, resolving disagreements with a third review author.

SELECTION CRITERIA

Diagnostic test accuracy and cohort studies were eligible for inclusion if they evaluated the test accuracy of EP, and MRI or pelvic floor ultrasound, or both, for the detection of posterior pelvic floor disorders in women with ODS. We excluded case-control studies. If studies partially met the inclusion criteria, we contacted the authors for additional information.

DATA COLLECTION AND ANALYSIS

Two review authors performed data extraction, including study characteristics, 'Risk-of-bias' assessment, sources of heterogeneity and test accuracy results. We excluded studies if test accuracy data could not be retrieved despite all efforts. We performed meta-analysis using Bayesian hierarchical latent class analysis. For the index test to qualify as a replacement test for EP, both sensitivity and specificity should be similar or higher than the historic reference standard (EP), and for a triage test either specificity or sensitivity should be similar or higher. We conducted heterogeneity analysis assessing the effect of different test conditions on test accuracy. We ran sensitivity analyses by excluding studies with high risk of bias, with concerns about applicability, or those published before 2010. We assessed the overall quality of evidence (QoE) according to GRADE.

MAIN RESULTS

Thirty-nine studies covering 2483 participants were included into the meta-analyses. We produced pooled estimates of sensitivity and specificity for all index tests for each target condition. Findings of the sensitivity analyses were consistent with the main analysis. Sensitivity of EP for diagnosis of rectocele was 98% (credible interval (CrI)94%-99%), enterocele 91%(CrI 83%-97%), intussusception 89%(CrI 79%-96%) and pelvic floor descent 98%(CrI 93%-100%); specificity for enterocele was 96%(CrI 93%-99%), intussusception 92%(CrI 86%-97%) and anismus 97%(CrI 94%-99%), all with high QoE. Moderate to low QoE showed a sensitivity for anismus of 80%(CrI 63%-94%), and specificity for rectocele of 78%(CrI 63%-90%) and pelvic floor descent 83%(CrI 59%-96%). Specificity of MRI for diagnosis of rectocele was 90% (CrI 79%-97%), enterocele 99% (CrI 96%-100%) and intussusception 97% (CrI 88%-100%), meeting the criteria for a triage test with high QoE. MRI did not meet the criteria to replace EP. Heterogeneity analysis showed that sensitivity of MRI performed with evacuation phase was higher than without for rectocele (94%, CrI 87%-98%) versus 65%, CrI 52% to 89%, and enterocele (87%, CrI 74%-95% versus 62%, CrI 51%-88%), and sensitivity of MRI without evacuation phase was significantly lower than EP. Specificity of transperineal ultrasound (TPUS) for diagnosis of rectocele was 89% (CrI 81%-96%), enterocele 98% (CrI 95%-100%) and intussusception 96% (CrI 91%-99%); sensitivity for anismus was 92% (CrI 72%-98%), meeting the criteria for a triage test with high QoE. TPUS did not meet the criteria to replace EP. Heterogeneity analysis showed that sensitivity of TPUS performed with rectal contrast was not significantly higher than without for rectocele(92%, CrI 69%-99% versus 81%, CrI 58%-95%), enterocele (90%, CrI 71%-99% versus 67%, CrI 51%-90%) and intussusception (90%, CrI 69%-98% versus 61%, CrI 51%-86%), and was lower than EP. Specificity of endovaginal ultrasound (EVUS) for diagnosis of rectocele was 76% (CrI 54%-93%), enterocele 97% (CrI 80%-99%) and intussusception 93% (CrI 72%-99%); sensitivity for anismus was 84% (CrI 59%-96%), meeting the criteria for a triage test with very low to moderate QoE. EVUS did not meet the criteria to replace EP. Specificity of dynamic anal endosonography (DAE) for diagnosis of rectocele was 88% (CrI 62%-99%), enterocele 97% (CrI 75%-100%) and intussusception 93% (CrI 65%-99%), meeting the criteria for a triage test with very low to moderate QoE. DAE did not meet the criteria to replace EP. Echodefaecography (EDF) had a sensitivity of 89% (CrI 65%-98%) and specificity of 92% (CrI 72%-99%) for intussusception, meeting the criteria to replace EP but with very low QoE. Specificity of EDF for diagnosis of rectocele was 89% (CrI 60%-99%) and for enterocele 97% (CrI 87%-100%); sensitivity for anismus was 87% (CrI 72%-96%), meeting the criteria for a triage test with low to very low QoE.

AUTHORS' CONCLUSIONS

In a population of women with symptoms of ODS, none of the imaging techniques met the criteria to replace EP. MRI and TPUS met the criteria of a triage test, as a positive test confirms diagnosis of rectocele, enterocele and intussusception, and a negative test rules out diagnosis of anismus. An evacuation phase increased sensitivity of MRI. Rectal contrast did not increase sensitivity of TPUS. QoE of EVUS, DAE and EDF was too low to draw conclusions. More well-designed studies are required to define their role in the diagnostic pathway of ODS.

Clinical applications of pelvic floor imaging: opinion statement endorsed by the society of abdominal radiology (SAR), American Urological Association (AUA), and American Urogynecologic Society (AUGS)

Pelvic floor dysfunction is prevalent, with multifactorial causes and variable clinical presentations. Accurate diagnosis and assessment of the involved structures commonly requires a multidisciplinary approach. Imaging is often complementary to clinical assessment, and the most commonly used modalities for pelvic floor imaging include fluoroscopic defecography, magnetic resonance defecography, and pelvic floor ultrasound. This collaboration opinion paper was developed by representatives from multiple specialties involved in care of patients with pelvic floor dysfunction (radiologists, urogynecologists, urologists, and colorectal surgeons). Here, we discuss the utility of imaging techniques in various clinical scenarios, highlighting the perspectives of referring physicians. The final draft was endorsed by the Society of Abdominal Radiology (SAR), American Urogynecologic Society (AUGS), and the American Urological Association (AUA).

MR defecography review

Pelvic floor dysfunction is a relatively common but often complex condition, presenting with a variety of clinical symptoms, especially when it involves multiple compartments. Clinical exam alone is often inadequate and requires a complementary imaging study. Magnetic resonance defecography (MRD) is an excellent noninvasive diagnostic study with its multiplanar capability, lack of ionizing radiation and excellent soft tissue resolution. It can identify both anatomic and functional abnormalities in the pelvic floor and specifically excels in its ability to simultaneously detect multicompartmental pathology and help with vital pre-operative assessment. This manuscript reviews the relevant anatomical landmarks, describes the optimal technique, highlights an approach to the interpretation of MRD, and provides an overview of the various pelvic floor disorders in the different anatomical compartments.

Mid- to Long-Term Magnetic Resonance Imaging Results of Two Prolapse Surgeries for Apical Defect: A Secondary Analysis of a Randomized Controlled Trial

OBJECTIVE

 Magnetic resonance imaging (MRI) has been considered another tool for use during the pre- and postoperative periods of the management of pelvic-organ prolapse (POP). However, there is little consensus regarding its practical use for POP and the association between MRI lines of reference and physical examination. We aimed to evaluate the mid- to long-term results of two surgical techniques for apical prolapse.

METHODS

 In total, 40 women with apical POP randomized from 2014 to 2016 underwent abdominal sacrocolpopexy (ASC group; n = 20) or bilateral vaginal sacrospinous fixation with an anterior mesh (VSF-AM group; n = 20). A physical examination using the POP Quantification System (POP-Q) for staging (objective cure) and the International Consultation on Incontinence Questionnaire-Vaginal Symptoms (ICIQ-VS: subjective cure), were applied and analyzed before and one year after surgery respectively. All MRI variables (pubococcigeous line [PCL], bladder base [BB], anorectal junction [ARJ], and the estimated levator ani subtended volume [eLASV]) were investigated one year after surgery. Significance was established at p < 0.05.

RESULTS

 After a mean 27-month follow-up, according to the MRI criteria, 60% of the women were cured in the VSF-AM group versus 45% in ASC group (p = 0.52). The POP-Q and objective cure rates by MRI were correlated in the anterior vaginal wall (p = 0.007), but no correlation was found with the subjective cure. The eLASV was larger among the patients with surgical failure, and a cutoff of ≥ 33.5 mm³ was associated with postoperative failure (area under the receiver operating characteristic curve [ROC]: 0.813; p = 0.002).

CONCLUSION

 Both surgeries for prolapse were similar regarding the objective variables (POP-Q measurements and MRI cure rates). Larger eLASV areas were associated with surgical failure.

Role of static and dynamic MRI in evaluation of pelvic posterior compartment pathologies: prospective case series

Background

Pelvic floor dysfunction affects the lifestyle of women worldwide; the aim of this study is to evaluate the role of static MRI and dynamic MR defecography in the diagnosis of the posterior compartment of pelvic floor dysfunction.

This prospective study included 50 female patients. All of them presented with pelvic floor dysfunction. Static and dynamic MRI were performed for all patients after injection of 120–150 ml of intrarectal gel and voiding 2 h before examination. Dynamic MRI was performed at rest, squeezing, straining phases, and during defecation.

Results

MR defecography can detect posterior compartment pathology with high sensitivity and specificity. We found anterior rectocele in 26 patients (52%). Rectocele incidence was analyzed and compared to postoperative reports, and the receiver operator curve (ROC) was calculated that showed area under the curve (AUC) of 0.998. The cut-off value of 1.95 cm gives a sensitivity of 96.4% and specificity of 100% during straining. The percentage of anismus was 26%, rectorectal intussusception 52%, anal prolapse types (rectoanal intussusception 14% and external prolapse 8%), and peritoneocele 34%.

Conclusion

MRI is a valuable imaging modality that can be used to diagnose pelvic floor disorders and does not involve the risk of exposure to ionizing radiation. It can direct the surgical procedure and thus improve the post-operative results and decrease the rate of recurrence due to missed pathology.

Dilemmas in Management of the Geriatric Bladder

Purpose of review

In this article, we will review current dilemmas regarding evaluation and management of the geriatric bladder incorporating concepts of normal changes of aging as well as common lower urinary tract dysfunction.

Recent findings

Increasing age leads to functional changes in essentially all organ systems including the genitourinary system. Understanding the natural changes with age of the bladder as well as the signs and symptoms of pathologic conditions is paramount to diagnosis and treatment of urologic conditions in the geriatric population.

Summary

There are several conundrums in the diagnosis and evaluation of the geriatric bladder including the ability of the bladder to store, empty, as well as sensitivity disturbances. Diagnostic testing and goals of treatment should be individualized for each patient and personalized to consider patient comorbidities, limitations, and expectations.

Relevance of open magnetic resonance imaging position (sitting and standing) to quantify pelvic organ prolapse in women

INTRODUCTION

In pelvic organ prolapse (POP), posture and gravity impact organ position and symptom severity. The advanced magnet configuration in open magnetic resonance imaging (MRO) allows patients to be imaged when sitting and standing, as well in a conventional supine position. This study evaluated if sitting and standing MRO images are relevant as a means of improving quantification of POP because they allow differences in organ position not seen on supine imaging to be identified.

METHODS

Forty women recruited from a university urogynecology clinic had MRO imaging (0.5 T scanner) with axial and sagittal T2-weighted pelvic scans obtained when sitting, standing, and supine. Pelvic reference lines were used to quantify the degree of POP, and the relevance of imaging position on the detection of POP compared.

RESULTS

Images from 40 participants were evaluated (20 with POP and 20 asymptomatic controls). Our results indicate that the maximal extent of prolapse is best evaluated in the standing position using H line, M line, mid-pubic line, and perineal line as reference lines to determine POP.

CONCLUSIONS

MRO imaging of symptomatic patients in a standing position is relevant in the quantification of POP. Compared with supine images, standing imaging identifies that greater levels of downward movement in the anterior and posterior compartments occur, presumably under the influence of posture and gravity. In contrast, no appreciable benefit was afforded by imaging in the sitting position, which precluded use of some reference lines due to upward movement of the anorectal junction.

Practical guide to dynamic pelvic floor MRI

Pelvic floor dysfunction encompasses a spectrum of functional disorders that result from impairment of the ligaments, fasciae, and muscles supporting the pelvic organs. It is a prevalent disorder that carries a lifetime risk over 10% for undergoing a surgical repair. Pelvic floor weakness presents as a wide range of symptoms, including pain, pelvic pressure or bulging, urinary and fecal incontinence, constipation, and sexual dysfunction. A correct diagnosis by clinical examination alone can be challenging, particularly in cases involving multiple compartments. Magnetic resonance imaging (MRI) allows noninvasive, radiation-free, high soft-tissue resolution evaluation of all three pelvic compartments, and has proved a reliable technique for accurate diagnosis of pelvic floor dysfunction. MR defecography with steady-state sequences allows detailed anatomic and functional evaluation of the pelvic floor. This article provides an overview of normal anatomy and function of the pelvic floor and discusses a practical approach to the evaluation of imaging findings of pelvic floor relaxation, pelvic organ prolapse, fecal incontinence, and obstructed defecation.

LEVEL OF EVIDENCE

5 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:1155-1170.

Modern Theories of Pelvic Floor Support : A Topical Review of Modern Studies on Structural and Functional Pelvic Floor Support from Medical Imaging, Computational Modeling, and Electromyographic Perspectives

PURPOSE OF REVIEW

Weakened pelvic floor support is believed to be the main cause of various pelvic floor disorders. Modern theories of pelvic floor support stress on the structural and functional integrity of multiple structures and their interplay to maintain normal pelvic floor functions. Connective tissues provide passive pelvic floor support while pelvic floor muscles provide active support through voluntary contraction. Advanced modern medical technologies allow us to comprehensively and thoroughly evaluate the interaction of supporting structures and assess both active and passive support functions. The pathophysiology of various pelvic floor disorders associated with pelvic floor weakness is now under scrutiny from the combination of (1) morphological, (2) dynamic (through computational modeling), and (3) neurophysiological perspectives. This topical review aims to update newly emerged studies assessing pelvic floor support function among these three categories.

RECENT FINDINGS

A literature search was performed with emphasis on (1) medical imaging studies that assess pelvic floor muscle architecture, (2) subject-specific computational modeling studies that address new topics such as modeling muscle contractions, and (3) pelvic floor neurophysiology studies that report novel devices or findings such as high-density surface electromyography techniques. We found that recent computational modeling studies are featured with more realistic soft tissue constitutive models (e.g., active muscle contraction) as well as an increasing interest in simulating surgical interventions (e.g., artificial sphincter). Diffusion tensor imaging provides a useful non-invasive tool to characterize pelvic floor muscles at the microstructural level, which can be potentially used to improve the accuracy of the simulation of muscle contraction. Studies using high-density surface electromyography anal and vaginal probes on large patient cohorts have been recently reported. Influences of vaginal delivery on the distribution of innervation zones of pelvic floor muscles are clarified, providing useful guidance for a better protection of women during delivery. We are now in a period of transition to advanced diagnostic and predictive pelvic floor medicine. Our findings highlight the application of diffusion tensor imaging, computational models with consideration of active pelvic floor muscle contraction, high-density surface electromyography, and their potential integration, as tools to push the boundary of our knowledge in pelvic floor support and better shape current clinical practice.

Prevalence of dynamic magnetic resonance imaging-identified pelvic organ prolapse in pre- and postmenopausal women without clinically evident pelvic organ descent

Background Dynamic magnetic resonance imaging (dMRI) is an imaging tool that can be used to evaluate and stage pelvic organ prolapse (POP). Greater understanding of the incidental detection of POP in asymptomatic patients is needed. Purpose To evaluate the prevalence of dMRI-detected POP in pre-and postmenopausal women who were imaged for reasons unrelated to pelvic floor dysfunction. Material and Methods A total of 227 women who had diagnoses that did not include POP underwent abdominal/pelvic dMRI. Patients with a positive gynecological examination for or a clinical history of POP ( n = 11), hysterectomy ( n = 4), or gynecologic-oncology surgery ( n = 2) were excluded, as well as patients who were unable to strain during MRI ( n = 11). A total of 199 patients without visible prolapse were enrolled in the study. An H-line, M-line, pubococcygeal line (PCL), and mid-pubic line (MPL) were used to detect and grade prolapse. Results The prevalence of dMRI-identified POP was higher in postmenopausal subjects. The PCL led to a greater frequency of prolapse detection than the MPL. The frequency of middle compartment descent was similar regardless of whether the PCL or MPL was used as a reference line. There was a higher incidence of prolapse in the posterior compartment. Using an H-line and PCL as references, the anterior and posterior compartments were found to significantly differ between pre- and postmenopausal subjects. The MRI parameters that were used to define POP were not correlated with parity, vaginal birth, BMI, or fetal birth weight. With respect to the MPL, age was correlated with both the presence of an elongated H-line and with descent. Conclusion Dynamic MRI identified incidental pelvic organ prolapse in asymptomatic patients. The prevalence of dMRI-detected POP was higher in postmenopausal women without visible prolapse. These findings suggest the need for further studies to identify how to modify the currently used dMRI thresholds for postmenopausal women.

[Changes in pelvic organ mobility and ligamentous laxity during pregnancy and postpartum. Review of literature and prospects]

INTRODUCTION

The role of pregnancy in pelvic floor disorders occurrence remains poorly known. It might exist a link between changes in ligamentous laxity and changes in pelvic organ mobility during this period. Our objective was to conduct a non-systematic review of literature about changes in pelvic organ mobility as well as in ligamentous laxity during pregnancy and postpartum.

METHODS

From the PubMed, Medline, Cochrane Library and Web of Science database we have selected works which pertains clinical assessment of pelvic organ mobility (pelvic organ prolapse quantification), ultrasound assessment of levator hiatus and urethral mobility, ligamentous laxity assessment during pregnancy and postpartum.

RESULTS

Clinical assessments performed in these works show an increase of pelvic organ mobility and perineal distension during pregnancy followed by a recovery phase during postpartum. Pelvic floor imaging shows an increase of levator hiatus area and urethral mobility during pregnancy then a recovery phase in postpartum. Different authors also report an increase of ligamentous laxity (upper and lower limbs) during pregnancy followed by a decrease phase in postpartum.

CONCLUSION

Pelvic organ mobility, ligamentous laxity, levator hiatus and urethral mobility change in a similarly way during pregnancy (increase of mobility or distension) and postpartum (recovery).

LEVEL OF EVIDENCE

3.

Advances in imaging diagnosis of rectocele

Rectocele is one of the common manifestations of outlet obstructive constipation. There are several imaging methods for evaluating rectocele including conventional defecography, dynamic nuclear magnetic resonance imaging (MRI) defecography and pelvic floor ultrasonography. These diagnostic techniques can identify the degree of rectocele and provide evidence for treatment. Defecography is still considered the gold standard for evaluating rectocele and guiding the operation, but it exposes patients to radiation. MRI defecography has the advantages of multi-dimensional imaging, excellent soft-tissue contrast and no radiation, and has broad prospects in the future, but it is expensive nowadays and has an unphysiological defecation way. Pelvic floor ultrasonography, especially endoanal and transperineal techniques, is able to identify all dysfunctions of the posterior pelvic floor compartment without radiation, but needs further studies.

Interobserver agreement of multicompartment ultrasound in the assessment of pelvic floor anatomy

OBJECTIVE

To assess the interobserver agreement of pelvic floor anatomical measurements using multicompartment pelvic floor ultrasound.

METHODS

Females were recruited from the urogynaecology/gynaecology clinics between July and October 2009 and underwent multicompartment pelvic floor ultrasonography (PFUS) using two-dimensional (2D) transperineal ultrasound (TPUS), high-frequency 2D/three-dimensional (3D) endovaginal ultrasound (EVUS) using a biplane probe with linear and transverse arrays and a 360° rotational 3D-EVUS. PFUS measurements were independently analysed by two clinicians.

RESULTS

158 females had PFUS assessment. Good-to-excellent interobserver agreement was observed for bladder-symphysis distance at rest and valsalva, urethral thickness, urethral length, urethral volume, levator hiatus area and width, anteroposterior diameter and anorectal angle. Lins Correlation was used to calculate the interobserver agreement and Bland-Altman plots were created to demonstrate the agreement between the researchers. There was also a good-to-excellent agreement between the two clinicians for the assessment of pelvic organ prolapse (POP) in the anterior, middle and posterior compartment.

CONCLUSION

Multicompartment PFUS is a reliable tool in the anatomical assessment of pelvic floor measurements and POP.

ADVANCES IN KNOWLEDGE

We found a good-to-excellent agreement between the two assessors in the assessment of pelvic floor measurements for all three pelvic floor compartments and suggest that multicompartment PFUS could be considered as a systematic integrated approach to assess the pelvic floor.

[Anatomy of the levator ani muscle and implications for obstetrics and gynaecology]

Pelvic floor disorders include urogenital and anorectal prolapse, urinary and faecal incontinence. These diseases affect 25% of patients. Most of time, treatment is primarily surgical with a high post-operative risk of recurrence, especially for pelvic organ prolapse. Vaginal delivery is the major risk factor for pelvic floor disorders through levator ani muscle injury or nerve damage. After vaginal delivery, 20% of patients experiment elevator ani trauma. These injuries are more common in case of instrumental delivery by forceps, prolonged second phase labor, increased neonatal head circumference and associated anal sphincter injuries. Moreover, 25% of patients have temporary perineal neuropathy. Recently, pelvic three-dimensional reconstructions from RMI data allowed a better understanding of detailed levator ani muscle morphology and gave birth to a clear new nomenclature describing this muscle complex to be developed. Radiologic and anatomic studies have allowed exploring levator ani innervation leading to speculate on the muscle and nerve damage mechanisms during delivery. We then reviewed the levator ani muscle anatomy and innervation to better understand pelvic floor dysfunction observed after vaginal delivery.