Effect of an Intrapartum Pelvic Dilator Device on Levator Ani Muscle Avulsion During Primiparous Vaginal Delivery: A Pilot Randomized Controlled Trial.

INTRODUCTION AND HYPOTHESIS: The objective was to evaluate the safety and effectiveness of an intrapartum electromechanical pelvic floor dilator designed to reduce the risk of levator ani muscle (LAM) avulsion during vaginal delivery. METHODS: A multicenter, randomized controlled trial enrolled nulliparous participants planning vaginal delivery. During the first stage of labor, participants were randomized to receive the intravaginal device or standard-of-care labor management. The primary effectiveness endpoint was the presence of full LAM avulsion on transperineal pelvic-floor ultrasound at 3 months. Three urogynecologists performed blinded interpretation of ultrasound images. The primary safety endpoint was adverse events (AEs) through 3 months. RESULTS: A total of 214 women were randomized to Device (n = 113) or Control (n = 101) arms. Of 113 Device assignees, 82 had a device placed, of whom 68 delivered vaginally. Of 101 Control participants, 85 delivered vaginally. At 3 months, 110 participants, 46 Device subjects who received full device treatment, and 64 Controls underwent ultrasound for the per-protocol analysis. No full LAM avulsions (0.0%) occurred in the Device group versus 7 out of 64 (10.9%) in the Control group (p = 0.040; two-tailed Fisher's test). A single maternal serious AE (laceration) was device related; no neonate serious AEs were device related. CONCLUSIONS: The pelvic floor dilator device significantly reduced the incidence of complete LAM avulsion in nulliparous individuals undergoing first vaginal childbirth. The dilator demonstrated an acceptable safety profile and was well received by recipients. Use of the intrapartum electromechanical pelvic floor dilator in laboring nulliparous individuals may reduce the rate of LAM avulsion, an injury associated with serious sequelae including pelvic organ prolapse.

Systematic Review and Meta-analysis of the Prevalence of Levator Ani Avulsion with Obstetric Anal Sphincter Injury and its Effects on Pelvic Floor Dysfunction.

INTRODUCTION AND HYPOTHESIS: The objective was to evaluate the prevalence of levator ani avulsion (LAA) among primiparous women with obstetric anal sphincter injury (OASI) and how this association could affect future pelvic floor dysfunction. METHODS: Three electronic databases (MEDLINE/PubMed/EMBASE) were searched in December 2018 and again in October 2022. Nine full-text articles were included in the analysis. The exclusion criteria were language other than English, studies not based on primiparous women only, conference abstracts, and evaluation without ultrasound or MRI. RESULTS: The overall prevalence of LAA was 24% (95% CI: 18-30%). Those with OASI, were at a higher risk of LAA, OR 3.49 (95% CI: 1.46 to 8.35). In women with LAA + OASI versus OASI alone, Three of Five studies showed worsened AI symptoms. Three of Five studies assessing urinary incontinence (UI) reported no significant difference in UI, whereas two reported increased UI. All studies that looked at pelvic organ prolapse reported a higher incidence of symptomatic prolapse and reduced pelvic floor muscle strength in women with LAA + OASI compared with those without LAA. CONCLUSION: Levator ani avulsion is prevalent following vaginal birth and is strongly associated with OASI. Incidence of AI does not increase in women with LAA and OASI, but they had greater symptom bother. OASI with LAA appears to increase the incidence of pelvic floor weakness and pelvic organ prolapse. There is no consensus agreement on the effect of LAA + OASI on UI.

Pelvic floor injury during vaginal birth is life-altering and preventable: what can we do about it?

Pelvic floor disorders after childbirth have distressing lifelong consequences for women, requiring more than 300,000 women to have surgery annually. This represents approximately 10% of the 3 million women who give birth vaginally each year. Vaginal birth is the largest modifiable risk factor for prolapse, the pelvic floor disorder most strongly associated with birth, and is an important contributor to stress incontinence. These disorders require 10 times as many operations as anal sphincter injuries. Imaging shows that injuries of the levator ani muscle, perineal body, and membrane occur in up to 19% of primiparous women. During birth, the levator muscle and birth canal tissues must stretch to more than 3 times their original length; it is this overstretching that is responsible for the muscle tear visible on imaging rather than compression or neuropathy. The injury is present in 55% of women with prolapse later in life, with an odds ratio of 7.3, compared with women with normal support. In addition, levator damage can affect other aspects of hiatal closure, such as the perineal body and membrane. These injuries are associated with an enlarged urogenital hiatus, now known as antedate prolapse, and with prolapse surgery failure. Risk factors for levator injury are multifactorial and include forceps delivery, occiput posterior birth, older maternal age, long second stage of labor, and birthweight of >4000 g. Delivery with a vacuum device is associated with reduced levator damage. Other steps that might logically reduce injuries include manual rotation from occiput posterior to occiput anterior, slow gradual delivery, perineal massage or compresses, and early induction of labor, but these require study to document protection. In addition, teaching women to avoid pushing against a contracted levator muscle would likely decrease injury risk by decreasing tension on the vulnerable muscle origin. Providing care for women who have experienced difficult deliveries can be enhanced with early recognition, physical therapy, and attention to recovery. It is only right that women be made aware of these risks during pregnancy. Educating women on the long-term pelvic floor sequelae of childbirth should be performed antenatally so that they can be empowered to make informed decisions about management decisions during labor.

A unified pelvic floor conceptual model for studying morphological changes with prolapse, age, and parity.

Several 2-dimensional and 3-dimensional measurements have been used to assess changes in pelvic floor structures and shape. These include assessment of urogenital and levator hiatus dimensions, levator injury grade, levator bowl volume, and levator plate shape. We argue that each assessment reflects underlying changes in an individual aspect of the overall changes in muscle and fascial structures. Vaginal delivery, aging, and interindividual variations in anatomy combine to affect pelvic floor structures and their connections in different ways. To date, there is no unifying conceptual model that permits the evaluation of how these many measures relate to one another or that reflects overall pelvic floor structure and function. Therefore, this study aimed to describe a unified pelvic floor conceptual model to better understand how the aforementioned changes to the pelvic floor structures and their biomechanical interactions affect pelvic organ support with vaginal birth, prolapse, and age. In this model, the pelvic floor is composed of 5 key anatomic structures: the (1) pubovisceral, (2) puborectal, and (3) iliococcygeal muscles with their superficial and inferior fascia; (4) the perineal membrane or body; and (5) the anal sphincter complex. Schematically, these structures are considered to originate from pelvic sidewall structures and meet medially at important connection points that include the anal sphincter complex, perineal body, and anococcygeal raphe. The pubovisceral muscle contributes primarily to urogenital hiatus closure, whereas the puborectal muscle is mainly related to levator hiatus closure, although each muscle contributes to the other. Dorsally and laterally, the iliococcygeal muscle forms a shelflike structure in women with normal support that spans the remaining area between these medial muscles and attachments to the pelvic sidewall. Other features include the levator plate, bowl volume, and anorectal angle. The pelvic floor conceptual model integrates existing observations and points out evident knowledge gaps in how parturition, injury, disease, and aging can contribute to changes associated with pelvic floor function caused by the detachment of one or more important connection points or pubovisceral muscle failure.

Three-dimensional endovaginal ultrasound assessment using the levator ani deficiency score in primiparas: A replication study.

INTRODUCTION: It is essential to assess the levator ani properly as part of clinical care in patients presenting with pelvic floor dysfunction. The levator ani deficiency scoring system is a previously published method to assess levator ani defects with three-dimensional endovaginal ultrasound. The primary aim of this study was to determine the intra- and interrater reliability of the levator ani deficiency score in a cohort of non-instrumentally delivered primiparas. MATERIAL AND METHODS: Primiparas (n = 141) were examined at least 1 year after vaginal birth. Three-dimensional endovaginal ultrasound volumes were acquired by a single examiner using two different automated ultrasound probes. The volumes were analyzed by two separate raters who were blinded to each other's assessments. Descriptive statistics were calculated for levator ani deficiency score and categorized into three levels (mild, moderate, severe). Kendall's tau-b was calculated for intra- and interrater comparisons. RESULTS: Intrarater comparisons of levator ani deficiency score and levator ani deficiency category were high (Kendall's tau-b ≥0.80 for Rater 1; >0.79 for Rater 2). Interrater comparisons of levator ani deficiency score and levator ani deficiency category were also high (Kendall's tau-b >0.9 for assessment 1 and >0.78 for assessment 2). Varying by rater, probe and assessment, 75.9%-80.1% of the study population had no/mild deficiency, 6.4%-9.2% had moderate deficiency, and 4.3%-6.4% had severe levator ani deficiency. CONCLUSIONS: The levator ani deficiency scoring system is a feasible method to assess defects of the levator ani muscle and can be reproduced with high intra- and interrater correlations. Using the scoring system in clinical practice may facilitate concordant assessment between different examiners. However, the system should be used to support clinical findings and symptomatology and not as a screening tool, as the score is lacking the category of no levator ani deficiency.

Management of levator ani avulsion: a systematic review and narrative synthesis.

PURPOSE: Levator ani muscle (LAM) avulsion affects up to 35% of women. Unlike obstetric anal sphincter injury, LAM avulsion is not diagnosed immediately after vaginal delivery, however, has a profound impact on quality of life. The management of pelvic floor disorders is in growing demand yet the significance of LAM avulsion in the context of pelvic floor dysfunction (PFD) is poorly understood. This study collates information on success of treatment for LAM avulsion to establish the best options for management of women. METHODS: MEDLINE®, MEDLINE® In-Process, EMBASE, PubMed, CINAHL and The Cochrane Library were searched for articles that evaluated the management techniques used to treat LAM avulsion. The protocol was registered with PROSPERO (CRD42021206427). RESULTS: Natural healing of LAM avulsion occurs in 50% of women. Conservative measures, including pelvic floor exercises and pessary use are poorly studied. Pelvic floor muscle training for major LAM avulsions was of no benefit. Post-partum pessary use was only of benefit in the first three months for women. Surgeries for LAM avulsion are poorly researched but studies suggest they may provide benefit for 76-97% of patients. CONCLUSIONS: Whilst some women with PFD secondary to LAM avulsion improve spontaneously, 50% continue to have pelvic floor symptoms 1 year following delivery. These symptoms result in a significant negative impact on quality of life, however, it is not clear whether conservative or surgical methods are helpful. There is a pressing need for research to find effective treatments and explore appropriate surgical repair techniques for women with LAM avulsion.

Impact of Laparoscopic Prolapse Repair in the Levator Hiatus Area.

STUDY OBJECTIVE: To determine whether laparoscopic surgery by sacrocolpopexy or sacrocervicopexy with posterior mesh attachment to levator ani to treat pelvic organ prolapse reduces the levator hiatus area, as measured by transperineal 3- and 4-dimensional ultrasound. The secondary objective was to assess the risk factors for prolapse recurrence. DESIGN: This is a prospective cohort study. SETTING: A university tertiary hospital. PATIENTS: Women with symptomatic apical prolapse at a high risk of recurrence were included. High risk of recurrence was defined as age <60 years and levator injury (avulsion and/or ballooning) or stage III-IV prolapse Pelvic Organ Prolapse Quantification. INTERVENTIONS: Women were treated with laparoscopic sacrocolpopexy or sacrocervicopexy. MEASUREMENTS AND MAIN RESULTS: Women underwent clinical examination according to assessment by the Pelvic Organ Prolapse Quantification system and transperineal ultrasound for the levator hiatus area at Valsalva. We collected demographic, clinical, and ultrasound data before surgery from clinical records and performed a comparative analysis of the levator hiatus areas before and after surgery and univariate and multivariate analyses of the risk factors for recurrence. Among the 30 women who enrolled, the levator hiatus area at Valsalva decreased significantly after surgery by an average of 4.68 cm2 (p = .028). However, despite a recurrence rate of 13.3%, we found no risk factors associated with recurrence in either the univariate or the multivariate analyses. CONCLUSION: Laparoscopic surgery by sacrocolpopexy or sacrocervicopexy for pelvic organ prolapse with mesh posterior attachment to levator ani significantly reduces the levator hiatus area measured by transperineal ultrasound. Further large-scale studies will be needed to confirm our results and identify risk factors for recurrence.

Is age at menarche a predictor of maternal birth trauma?

OBJECTIVE: Age at menarche and the interval between menarche and age at first vaginal birth have been shown to be associated with reproductive performance; however, their association with maternal birth trauma has not been studied. We aimed to determine whether age at menarche, age at first vaginal birth and their interval are associated independently with levator ani muscle (LAM) avulsion and external anal sphincter (EAS) defect. METHODS: This was a retrospective analysis of the ultrasound volume datasets of 466 vaginally parous patients attending one of two tertiary urogynecological units in Australia. All patients had undergone a standardized interview and clinical examination using the pelvic organ prolapse quantification staging system, followed by four-dimensional translabial ultrasound. Tomographic ultrasound imaging was used to evaluate the LAM for avulsion and the EAS for significant defect. RESULTS: Of the 466 women analyzed, LAM avulsion was diagnosed in 121 (26.0%) and significant EAS defect in 55 (11.8%). Logistic regression analysis showed no association between age at menarche and LAM avulsion (P = 0.67). Weak but significant associations were noted between LAM avulsion and age at first vaginal birth (odds ratio (OR), 1.070 (95% CI, 1.03-1.11); P = 0.0007) and between LAM avulsion and menarche-to-first-vaginal-birth interval (OR, 1.064 (95% CI, 1.02-1.11); P = 0.0018). No significant associations were noted between significant EAS defect and any of the evaluated variables (all P ≥ 0.49). CONCLUSIONS: Age at menarche is not predictive of maternal birth trauma i.e. LAM avulsion and EAS residual defect. There was a statistically significant association between LAM avulsion and menarche-to-first-vaginal-birth interval; however, this was not stronger than the previously established association between LAM avulsion and age at first vaginal birth, arguing against any distinct effect of prolonged prepregnancy hormonal stimulation on the biomechanical properties of the pelvic floor. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Vaginal birth after Cesarean section and levator ani avulsion: a case-control study.

OBJECTIVE: The aim of this study was to explore the risk of levator ani muscle (LAM) avulsion and enlargement of the levator hiatus following vaginal birth after Cesarean section (VBAC) in comparison with vaginal delivery in primiparous women. METHODS: In this two-center observational case-control study, we identified all women who had a term VBAC for their second delivery at the Departments of Obstetrics and Gynecology at the Faculty of Medicine in Pilsen and the 1st Faculty of Medicine in Prague, Charles University, Czech Republic, between 2012 and 2016. Women with a repeat VBAC, preterm birth or stillbirth were excluded from the study. As a control group, we enrolled a cohort of primiparous women who delivered vaginally during the study period. To increase our control sample, we also invited all primiparous women who delivered vaginally in both participating units between May and June 2019 to participate. All participants were invited for a four-dimensional pelvic floor ultrasound scan to assess LAM trauma. LAM avulsion and the area of the levator hiatus were assessed offline from the stored pelvic floor volumes obtained at rest, during maximum contraction and during Valsalva maneuver. The laterality of the avulsion was also noted. The cohorts were then compared using the χ2 test and Wilcoxon's two-sample test according to the normality of the distribution. P < 0.05 was considered statistically significant. Multivariate regression analysis, controlling for age and body mass index (BMI), was also performed. RESULTS: A total of 356 women had a VBAC for their second delivery during the study period. Of these, 152 (42.7%) attended the ultrasound examination and full data were available for statistical analysis for 141 women. The control group comprised 113 primiparous women. A significant difference was observed between the VBAC group and the control group in age (32.7 vs 30.1 years; P < 0.05), BMI (28.4 vs 27.4 kg/m2 ; P < 0.05) and duration of the first and second stages of labor (293.1 vs 345.9 min; P < 0.05 and 27.6 vs 35.3 min; P < 0.05, respectively) at the time of the index birth. The LAM avulsion rate was significantly higher in the VBAC compared with the control group (32.6% vs 18.6%; P = 0.01). The difference between the groups was observed predominantly in the rate of unilateral avulsion and remained significant after controlling for age and BMI (adjusted odds ratio 2.061 (95% CI, 1.103-3.852)). There was no statistically significant difference in the area of the levator hiatus at rest (12.0 vs 12.6 cm2 ; P = 0.28) or on maximum Valsalva maneuver (18.6 vs 18.7 cm2 ; P = 0.55) between the VBAC and control groups. The incidence of levator hiatal ballooning was comparable between the groups (17.7% and 18.6%; P = 0.86). CONCLUSIONS: VBAC is associated with a significantly higher rate of LAM avulsion than is vaginal birth in nulliparous women. The difference was significant even after controlling for age and BMI. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Delivery mode, levator avulsion and obstetric anal sphincter injury: A cross-sectional study 20 years after childbirth.

BACKGROUND: Levator ani muscle (LAM) and anal sphincter injuries are common after vaginal birth and are associated with pelvic organ prolapse and anal incontinence. AIMS: Our objective was to investigate long-term association between delivery mode, LAM avulsion and obstetric anal sphincter injuries (OASIS) in women at least 20 years after their first birth. METHODS: All women recruited at 'index birth' of the Dunedin (New Zealand) arm of ProLong (PROlapse and incontinence LONG-term research) Study, were invited to have translabial and transperineal ultrasound assessment of LAM and anal sphincters. Post-processing analysis of imaging data was performed blinded against delivery data. Statistical analysis was performed using the χ2 test and results are expressed as odds ratios (OR). RESULTS: Of the initial 1250 participants, 196 women returned for examination. Mean age was 50.8 years with a mean body mass index of 27.6 and median parity was three. They were seen on average 23 years after their first delivery. Four data sets were unavailable and one declined ultrasound assessment, leaving 191 for analysis. LAM avulsion was diagnosed in 29 (15.2%), and 24 women (12.6%) had significant anal sphincter defect. LAM avulsion was associated with forceps delivery (OR 2.45, 95% CI 1.04-5.80, P = 0.041). Forceps conveyed a greater risk of OASIS (21%) compared to a spontaneous vaginal delivery (11%) but did not reach statistical significance. CONCLUSIONS: Forceps delivery is associated with long-term injurious effect on pelvic floor structures. Discussions of the long-term negative impact of pelvic floor structures and their functions are necessary to achieve an informed consent toward an operative vaginal delivery.

New Method for Assessment of Levator Avulsion Injury: A Comparative Elastography Study.

OBJECTIVE: The aim of this study was to introduce elastography as a new method for sonographic assessment of postpartum pelvic floor trauma. METHODS: We examined 86 postpartum primiparous women, of whom 43 had undergone primary caesarean section (group_CS) and 43 vaginal delivery (group_VD). In a puborectal-symphysis plane, B-mode and elastographic ultrasonography were used to evaluate pelvic floor trauma. The strain value of left and right puborectal muscle was assessed close to the symphysis (Trauma_Elastography). The strain ratio maximum of this measurement was stored (Trauma_Index). RESULTS: The elastographic evaluation revealed more trauma-suspicious lesions than the B-mode investigation (60.5% versus 39.5%; P < .001). The median Trauma_Index was higher in group_VD compared to group_CS (1.63 versus 1.18; P < .001). CONCLUSION: Sonographic elastography assessment in a new examination plane shows postpartum trauma of the pelvic floor in women after vaginal delivery. This new method may help to identify women with a higher risk of postpartum pelvic floor disorders.

Association between pelvic organ prolapse types and levator-urethra gap as measured by 3D transperineal ultrasound.

OBJECTIVES: To evaluate the association between pelvic organ prolapse (POP) types and levator-urethra gap (LUG) as measured by 3-dimensional transperineal tomographic ultrasound. METHODS: A retrospective study was carried out on 98 women with symptomatic POP. Three-dimensional transperineal tomographic ultrasound images and POP quantification coordinates were reviewed. Each vaginal compartment was staged for the degree of prolapse, and total number of involved compartments identified. LUG was measured on 3-dimensional tomographic sonograms as the distance between the center of the urethra and the levator insertion bilaterally. Based on prior studies, an abnormal LUG of 25 mm or greater indicated levator avulsion. The LUG and the presence or absence of unilateral/bilateral avulsions was analyzed with reference to the clinical diagnosis of prolapse (single versus multicompartment, and mild [stage II] versus severe [stage III-IV]). Generalized logit models were used to evaluate the association between avulsion and prolapse type and stage. RESULTS: The LUG was substantially larger in women with multicompartment compared to single-compartment POP (28.9 ± 4.1 mm versus 22.7 ± 4.1 mm, P < .01). Similarly, LUG was substantially larger in women with severe (stage III-IV) compared to mild (stage II) POP (28.8 ± 4.7 mm versus 23.3 ± 4.5 mm, P < .01). Women with severe prolapse were 32 times more likely than women with mild prolapse to have bilateral levator avulsion. Those with POP involving all 3 vaginal compartments were 76 times more likely than single-compartment POP to have bilateral levator avulsions. CONCLUSIONS: Bilateral levator ani avulsion as diagnosed by LUG measurements of 25 mm or greater at rest is associated with multicompartment, severe prolapse.

It is the first birth that does the damage: a cross-sectional study 20 years after delivery.

INTRODUCTION AND HYPOTHESIS: Levator ani muscle (LAM) and anal sphincter tears are common after vaginal birth and are associated with female pelvic organ prolapse and anal incontinence. The impact of subsequent births on LAM and external anal sphincter (EAS) integrity is less well defined. The objective of this study was to determine the prevalence of LAM and EAS trauma in primiparous (VP1) and multiparous (VP2+) women who had delivered vaginally to assess if there were differences between the two groups. The null hypothesis was: there is no significant difference in the prevalence of LAM and EAS trauma between the two groups. METHODS: This was a cross-sectional study involving 195 women, participants of the Dunedin arm of the ProLong study (PROlapse and incontinence LONG-term research study) seen 20 years after their index birth. Assessment included a standardized questionnaire, ICS POP-Q and 4D translabial ultrasound. Post-imaging analysis of LAM and EAS integrity was undertaken blinded against other data. Statistical analysis was performed using Fisher's exact test and results were expressed as odds ratios (OR). RESULTS: LAM avulsion and EAS defects were diagnosed in 31 (16%) and 24 (12.4%) women respectively. No significant difference in the prevalence of levator avulsion and EAS defects between primiparous (VP1) and multiparous (VP2+) women who had delivered vaginally (OR 1.9, 95% CI 0.72-5.01, p = 0.26) and (OR 1.2, 95% CI 0.4-3.8, p = 0.76) respectively. CONCLUSIONS: Most LAM avulsions and EAS defects seem to be caused by the first vaginal birth. Subsequent vaginal deliveries after the first were unlikely to cause further LAM trauma.

The association between maternal age at first delivery and risk of obstetric trauma.

BACKGROUND: There are a number of poor birth outcomes with advancing maternal age. Although there is some evidence of a higher risk of trauma to obstetric anal sphincter and the levator ani muscle with advancing age, findings to date are inconclusive. OBJECTIVE: The aim of this study was to assess the risk of pelvic floor injury using translabial 3- and 4-dimensional ultrasound relative to advancing maternal age in primiparous women after a singleton vaginal delivery at term and to determine any association between maternal age and obstetric trauma, including obstetric anal sphincter injuries, levator avulsion, and irreversible overdistension of the levator hiatus. STUDY DESIGN: This is a subanalysis of a perinatal intervention trial conducted in a specialist urogynecology referral unit at 2 tertiary units. All primiparous women with singleton birth at term underwent 3- and 4-dimensional translabial pelvic floor ultrasound both ante- and postnatally for the assessment of the obstetric trauma including levator ani muscle avulsion, hiatal overdistension to 25 cm(2) or more, and obstetric anal sphincter injuries. A multivariate logistic regression analysis was performed to examine the association between maternal age and obstetric trauma diagnosed on 3- and 4-dimensional translabial ultrasound. Multiple confounders were included, and the most significant (forceps and vacuum delivery) were used for probability modeling. RESULTS: Of 660 women recruited for the original study, a total of 375 women who had a vaginal delivery with complete data sets were analyzed. A total of 174 women (46.4%) showed evidence of at least 1 form of major pelvic floor trauma. Advancing maternal age at first delivery carries with it a significant incremental risk of major pelvic floor trauma with an odds ratio of 1.064 for overall risk of injury for each increasing year of age past age 18 years (P = .003). The probability of any type of trauma appears to be substantially higher for forceps delivery. Vacuum delivery appears to increase the risk of obstetric anal sphincter injuries but not of levator avulsion. CONCLUSION: There is a significant association between the risk of major pelvic floor injury and increasing maternal age at first delivery.

The natural history of levator avulsion one year following childbirth: a prospective study.

OBJECTIVE: To explore the natural history of levator avulsion in primipara 1 year postpartum and correlate this to pelvic floor dysfunction (PFD). DESIGN: Observational longitudinal cohort study. SETTING: District General University Hospital. POPULATION OR SAMPLE: Nullipara at 36 weeks of gestation, 3 months and 1 year postpartum. METHODS: Validated methods assessed muscle strength, prolapse, ultrasound measurements of levator hiatus and avulsion, and questionnaires for sexual function, and urinary and anal incontinence. Pattern differences over time were evaluated using linear mixed models. MAIN OUTCOME MEASURES: Natural history of levator avulsion and relationship with PFD. RESULTS: Of the 269 nullipara, 191 returned at 3 months and 147 (55%) at 1 year postpartum; 109 had a vaginal delivery and 38 had a caesarean delivery. Sixty-two percent (n = 13/21; 95% CI 41-79%) of levator avulsions diagnosed 3 months postpartum were no longer evident at 1 year. Following vaginal delivery, nine women (8%, 95% CI 4.2-15.1%) had persistent levator avulsion. Most changes in PFD occurred between the antenatal and first postnatal visit, without improvement at 1 year. Women with persistent levator avulsion had significantly worse deterioration patterns of muscle strength, hiatus measurements and vaginal symptoms (loose vagina/lump sensation). However, evidence of PFD was also related to no longer evident levator avulsion. CONCLUSIONS: Sixty-two percent of levator avulsions were no longer evident 1 year postpartum. Partial avulsion has a tendency to improve over time, which seems to be less common for complete levator avulsions. Women with no longer evident and persistent levator avulsion had PFD, with worse patterns in presence of persistent avulsion.

Does the prevalence of levator ani muscle avulsion differ when assessed using tomographic ultrasound imaging at rest vs on maximum pelvic floor muscle contraction?

OBJECTIVE: It has been suggested that transperineal ultrasound images obtained during maximum pelvic floor muscle contraction improve the diagnosis of levator ani muscle (LAM) avulsion by comparison with those obtained at rest. The objective of this study was to establish, using transperineal tomographic ultrasound imaging (TUI), the correlation between LAM avulsion diagnosed at rest and that on contraction. METHODS: Primiparous women were examined 3 months postpartum by Pelvic Organ Prolapse Quantification (POP-Q) assessment and for LAM avulsion clinically by digital palpation and by transperineal TUI performed at rest and on pelvic floor muscle contraction. LAM avulsion was diagnosed on TUI when the three central slices were abnormal. A comparison was made between LAM avulsion diagnosed at rest and on maximum contraction. Two independent blinded investigators performed the analyses and a third investigator resolved discrepancies. RESULTS: One hundred and ninety primiparae were analyzed providing 380 results for comparison, as right and left LAM were analyzed independently. LAM avulsion was found in 36 (9.5%) images obtained at rest and in 35 (9.2%) on contraction, revealing moderate correlation between the two (ICC, 0.58 (95% CI, 0.51-0.64)). Twenty-two cases of LAM avulsion were identified both at rest and on contraction. One woman had LAM avulsion on palpation, which was seen on TUI as LAM avulsion on contraction, but not at rest. More cases of anterior and posterior compartment prolapse were found in women with LAM avulsion diagnosed on contraction only compared to LAM avulsion observed at rest only (POP-Q assessment point Ba, -1.8 vs -2.5 (P = 0.075) and point Bp, -2.5 vs -2.8 (P = 0.072)). CONCLUSIONS: Findings on transperineal TUI performed in women at rest and on contraction correlate reasonably well. However, given the trend towards an association with signs of pelvic floor dysfunction, diagnosis of LAM avulsion on contraction seems to be more reliable. Consistency in technique and interpretation should be maintained.

Levator ani muscle avulsion during childbirth: a risk prediction model.

OBJECTIVE: To establish the incidence of levator ani muscle (LAM) avulsion in primiparous women and to develop a clinically applicable risk prediction model. DESIGN: Observational longitudinal cohort study. SETTING: District General University Hospital, United Kingdom. SAMPLE: Nulliparous women at 36 weeks of gestation and 3 months postpartum. METHODS: Four-dimensional transperineal ultrasound was performed during both visits. Tomographic ultrasound imaging at maximum contraction was used to diagnose no, minor or major LAM avulsion. A risk model was developed using multivariable ordinal logistic regression. MAIN OUTCOME MEASURES: Incidence of LAM avulsion and its risk factors. RESULTS: Of 269 women with no antenatal LAM avulsion 71% (n = 191) returned postpartum. No LAM avulsion was found after caesarean section (n = 48). Following vaginal delivery the overall incidence of LAM avulsion was 21.0% (n = 30, 95% confidence interval [95% CI] 15.1-28.4). Minor and major LAM avulsion were diagnosed in 4.9% (n = 7, 95% CI 2.2-9.9) and 16.1% (n = 23, 95% CI 10.9-23.0), respectively. Risk factors were obstetric anal sphincter injuries (odds ratio [OR] 4.4, 95% CI 1.6-12.1), prolonged active second stage of labour per hour (OR 2.2, 95% CI 1.4-3.3) and forceps delivery (OR 6.6, 95% CI 2.5-17.2). A risk model and nomogram were developed to estimate a woman's individual risk: three risk factors combined revealed a 75% chance of LAM avulsion. CONCLUSIONS: Twenty-one percent of women sustain LAM avulsion during their first vaginal delivery. Our risk model and nomogram are novel tools to estimate individual chances of LAM avulsion. We can now target postnatal women at risk of sustaining a LAM avulsion.

The relationship between postpartum levator ani muscle avulsion and signs and symptoms of pelvic floor dysfunction.

OBJECTIVE: To establish the relationship between postpartum levator ani muscle (LAM) avulsion and signs and/or symptoms of pelvic floor dysfunction (PFD). DESIGN: Observational longitudinal cohort study. SETTING: District General University Hospital, UK. POPULATION OR SAMPLE: Primigravida at 36 weeks' gestation and 3 months postpartum. METHODS: Pelvic floor muscle strength (PFMS) and pelvic organ prolapse were assessed clinically using validated methods. Transperineal ultrasound was performed to identify LAM avulsion and measure hiatus dimensions. Validated questionnaires evaluated sexual function, urinary and faecal incontinence. MAIN OUTCOME MEASURES: PFD signs and symptoms related to LAM avulsion. RESULTS: Two hundred and sixty nine primigravida without LAM avulsion participated and 71% (n = 191) returned postpartum. LAM avulsion was found in 21% of vaginal deliveries (n = 30, 95%CI 15.1-28.4%). Women with minor and major avulsion had worse PFMS (P < 0.038) and more anterior compartment prolapse (maximum stage 2; P < 0.024). Antenatal hiatus antero-posterior diameter on ultrasound was significantly smaller in women sustaining avulsion (P = 0.011). Postnatal measurements were significantly increased following avulsion. Women with major avulsion were less sexually active at both antenatal and postnatal periods (P < 0.030). These women had more postnatal urinary incontinence and symptoms such as reduced vaginal sensation and 'too loose vagina'. No postnatal differences were found for faecal incontinence, prolapse symptoms or quality of life. The correlation of differences in variables was only slight-fair with avulsion severity. CONCLUSIONS: Twenty one percent of women sustain LAM avulsion during their first vaginal delivery with significant impact on signs and symptoms of PFD. As avulsion has been described as the missing link in the development of prolapse; longer term follow-up is vital.