Clinical consequences of levator trauma

The prevention of perineal trauma during vaginal birth

Perineal trauma after vaginal birth is common, with approximately 9 of 10 women being affected. Second-degree perineal tears are twice as likely to occur in primiparous births, with a incidence of 40%. The incidence of obstetrical anal sphincter injury is approximately 3%, with a significantly higher rate in primiparous than in multiparous women (6% vs 2%). Obstetrical anal sphincter injury is a significant risk factor for the development of anal incontinence, with approximately 10% of women developing symptoms within a year following vaginal birth. Obstetrical anal sphincter injuries have significant medicolegal implications and contribute greatly to healthcare costs. For example, in 2013 and 2014, the economic burden of obstetrical anal sphincter injuries in the United Kingdom ranged between £3.7 million (with assisted vaginal birth) and £9.8 million (with spontaneous vaginal birth). In the United States, complications associated with trauma to the perineum incurred costs of approximately $83 million between 2007 and 2011. It is therefore crucial to focus on improvements in clinical care to reduce this risk and minimize the development of perineal trauma, particularly obstetrical anal sphincter injuries. Identification of risk factors allows modification of obstetrical practice with the aim of reducing the rate of perineal trauma and its attendant associated morbidity. Risk factors associated with second-degree perineal trauma include increased fetal birthweight, operative vaginal birth, prolonged second stage of labor, maternal birth position, and advanced maternal age. With obstetrical anal sphincter injury, risk factors include induction of labor, augmentation of labor, epidural, increased fetal birthweight, fetal malposition (occiput posterior), midline episiotomy, operative vaginal birth, Asian ethnicity, and primiparity. Obstetrical practice can be modified both antenatally and intrapartum. The evidence suggests that in the antenatal period, perineal massage can be commenced in the third trimester of pregnancy to increase muscle elasticity and allow stretching of the perineum during birth, thereby reducing the risk of tearing or need for episiotomy. With regard to the intrapartum period, there is a growing body of evidence from the United Kingdom, Norway, and Denmark suggesting that the implementation of quality improvement initiatives including the training of clinicians in manual perineal protection and mediolateral episiotomy can reduce the incidence of obstetrical anal sphincter injury. With episiotomy, the International Federation of Gynecology and Obstetrics recommends restrictive rather than routine use of episiotomy. This is particularly the case with unassisted vaginal births. However, there is a role for episiotomy, specifically mediolateral or lateral, with assisted vaginal births. This is specifically the case with nulliparous vacuum and forceps births, given that the use of mediolateral or lateral episiotomy has been shown to significantly reduce the incidence of obstetrical anal sphincter injury in these groups by 43% and 68%, respectively. However, the complications associated with episiotomy including perineal pain, dyspareunia, and sexual dysfunction should be acknowledged. Despite considerable research, interventions for reducing the risk of perineal trauma remain a subject of controversy. In this review article, we present the available data on the prevention of perineal trauma by describing the risk factors associated with perineal trauma and interventions that can be implemented to prevent perineal trauma, in particular obstetrical anal sphincter injury.

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.

Transvaginal Two-Dimensional Ultrasound Evaluation as a Screening Tool for Levator ani Muscle Avulsion in Postpartum Women

OBJECTIVES

To evaluate the agreement between two-dimensional transvaginal ultrasound (2D-TVUS) and transperineal tomographic ultrasound imaging on three-dimensional (3D) volume in diagnosing levator ani muscle (LAM) avulsion of postpartum women. Furthermore, we tested the repeatability of the 2D-TVUS in measuring the LAM thickness.

METHODS

A retrospective study was performed using the data sets from postpartum women. One doctor measured the thickness of the LAM on the images at the attachment to the arcus tendinous levator ani and the middle part using the 2D-TVUS ultrasound data sets of postpartum women. These women were examined twice, at 42-56 days and 3-6 months postpartum. Intra-observer repeatability was expressed using intraclass correlation coefficients (ICCs). The other doctor judged whether there was avulsion in the LAM on the 2D-TVUS and transperineal tomography imaging on the 3D volume. The inter-method agreement was determined using Cohen's kappa coefficient (k).

RESULTS

Thickness measurements of the middle part and attachment of the LAM by 2D-TVUS showed excellent and good intra-observer repeatability (ICC 0.84; 95% CI, 0.76-0.88, and ICC 0.74; 95% CI, 0.67-0.84, respectively). The overall agreement was 92% (Cohen's kappa was 0.79) between 2D-TVUS and transperineal tomographic imaging. Compared to transperineal tomographic imaging in the diagnosis of LAM avulsion, the diagnostic sensitivity of 2D-TVUS was 91.7%, the specificity was 92.1%.

CONCLUSIONS

The 2D-TVUS technique, a simple and reproducible method for assessing LAM avulsion, may be helpful as a screening tool for LAM avulsion of postpartum women.

A review of levator ani avulsion after childbirth: Incidence, imaging and management

Key Content • Levator ani muscle (LAM) avulsion injury occurs occultly during childbirth, most commonly during operative vaginal deliveries. • Injuries of levator ani have long term sequelae for pelvic floor health. As life expectancy increases the burden of disease upon urogynaecology services will need to be considered. • Diagnosis of this condition can be difficult as there is no agreed 'gold standard' imaging modality. • There is no consensus regarding surgical management of LAM avulsion. Learning objectives • Review anatomy and function of levator ani muscle • Identify the risk factors for levator ani avulsion injury • Role of imaging to appropriately identify LAM injury and current management options including appropriate follow up • Management of subsequent pregnancy following LAM avulsion Ethical issues • Is there value to the patient in diagnosing levator ani avulsion when there is no recommended treatment for these injuries?

Levator ani muscle coactivation at term is associated with longer second stage of labor in nulliparous women

OBJECTIVE

To assess the effect of levator ani muscle (LAM) coactivation at term on outcome of labor in nulliparous women.

METHODS

This was a prospective study of 284 low-risk nulliparous women with a singleton pregnancy at term recruited before the onset of labor. The anteroposterior diameter of the levator hiatus was measured in each woman on transperineal ultrasound at rest, on maximum pelvic floor muscle contraction and on maximum Valsalva maneuver before and after visual feedback. LAM coactivation was defined as a reduction in the anteroposterior diameter of the levator hiatus on maximum Valsalva maneuver in comparison with that at rest. The association of pelvic hiatal diameter values and LAM coactivation with mode of delivery and duration of labor was assessed.

RESULTS

No significant difference was found between women who underwent Cesarean delivery and those who had a vaginal delivery with regard to the anteroposterior diameter of the levator hiatus at rest, on pelvic floor muscle contraction and on Valsalva maneuver. Longer second stage of labor was associated with shorter anteroposterior diameter of the levator hiatus on all assessments, but in particular at rest and on Valsalva both before and after visual feedback. LAM coactivation was found in 89 (31.3%) and 75 (26.4%) women before and after visual feedback, respectively. Post visual feedback, women with LAM coactivation had a significantly longer second stage of labor than did those without LAM coactivation (83 ± 63 vs 63 ± 42 min; P = 0.006). On Cox regression analysis, LAM coactivation post visual feedback was an independent predictor of longer second stage of labor (adjusted hazard ratio, 1.499 (95% CI, 1.076-2.087); P = 0.017).

CONCLUSION

LAM coactivation in nulliparous women at term is associated with a longer second stage of labor. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Atraumatic normal vaginal delivery: how many women get what they want?

BACKGROUND

Trauma to the perineum, levator ani complex, and anal sphincter is common during vaginal childbirth, but often clinically underdiagnosed, and many women are unaware of the potential for long-term damage.

OBJECTIVE

In this study we use transperineal ultrasound to identify how many women will achieve a normal vaginal delivery without substantial damage to the levator ani or anal sphincter muscles, and to create a model to predict patient characteristics associated with successful atraumatic normal vaginal delivery.

STUDY DESIGN

This is a retrospective, secondary analysis of data sets gathered in the context of an interventional perinatal imaging study. A total of 660 primiparas, carrying an uncomplicated singleton pregnancy, underwent an antepartum and postpartum interview, vaginal exam (Pelvic Organ Prolapse Quantification), and 4-dimensional translabial ultrasound. Ultrasound data were analyzed for levator trauma and/or overdistention and residual sphincter defects. Postprocessing analysis of ultrasound volumes was performed blinded against clinical data and analyzed against obstetric data retrieved from the local maternity database. Levator avulsion was diagnosed if the muscle insertion at the inferior pubic ramus at the plane of minimal hiatal dimensions and within 5 mm above this plane on tomographic ultrasound imaging was abnormal, ie the muscle was disconnected from the inferior pubic ramus. Hiatal overdistensibility (microtrauma) was diagnosed if there was a peripartum increase in hiatal area on Valsalva by >20% with the resultant area ≥25 cm². A sphincter defect was diagnosed if a gap of >30 degrees was seen in ≥4 of 6 tomographic ultrasound imaging slices bracketing the external anal sphincter. Two models were tested: a first model that defines severe pelvic floor trauma as either obstetric anal sphincter injury or levator avulsion, and a second, more conservative model, that also included microtrauma.

RESULTS

A total of 504/660 women (76%) returned for postpartum follow-up as described previously. In all, 21 patients were excluded due to inadequate data or intercurrent pregnancy, leaving 483 women for analysis. Model 1 defined nontraumatic vaginal delivery as excluding operative delivery, obstetric anal sphincter injuries, and sonographic evidence of levator avulsion or residual sphincter defect. Model 2 also excluded microtrauma. Of 483 women, 112 (23%) had a cesarean delivery, 103 (21%) had an operative vaginal delivery, and 17 (4%) had a third-/fourth-degree tear, leaving 251 women who could be said to have had a normal vaginal delivery. On ultrasound, in model 1, 27 women (6%) had an avulsion and 31 (6%) had a residual defect, leaving 193/483 (40%) who met the criteria for atraumatic normal vaginal delivery. In model 2, an additional 33 women (7%) had microtrauma, leaving only 160/483 (33%) women who met the criteria for atraumatic normal vaginal delivery. On multivariate analysis, younger age and earlier gestation at time of delivery remained highly significant as predictors of atraumatic normal vaginal delivery in both models, with increased hiatal area on Valsalva also significant in model 2 (all P ≤ .035).

CONCLUSION

The prevalence of significant pelvic floor trauma after vaginal child birth is much higher than generally assumed. Rates of obstetric anal sphincter injury are often underestimated and levator avulsion is not included as a consequence of vaginal birth in most obstetric text books. In this study less than half (33-40%) of primiparous women achieved an atraumatic normal vaginal delivery.

Can we evaluate the levator ani after Kegel exercise in women with pelvic organ prolapse by transperineal elastography? A preliminary study

OBJECTIVES

The aim of this study was to evaluate the stiffness variation of the levator ani in patients with stage I/II pelvic organ prolapse (POP) before and after Kegel exercises by transperineal elastography.

METHODS

A total of 20 patients who were diagnosed with staged I/II POP underwent conventional transperineal ultrasound and elastography. For each patient, the levator ani was located and evaluated in the state of Valsalva. After Kegel exercises for 12 weeks, transperineal ultrasound and elastography were repeated. The elasticity images were assessed using a four-point scale scoring system.

RESULTS

Of the 20 cases, four had an elastography score of 1, 14 had a score of 2, two had a score of 3, and no cases had a score of 4 in the levator ani before Kegel exercises. After Kegel exercises, one had an elastography score of 1, two had a score of 2, 15 had a score of 3, and two cases had a score of 4. The mean elastography score was statistically significantly higher for the levator ani after Kegel exercises (2.90 ± 0.48) than for the baseline score (1.90 ± 0.29) (p = 0.025).

CONCLUSIONS

Transperineal elastography was an effective and useful tool in the evaluation of the levator ani in patients with POP-Q stage I/II before and after Kegel exercises.

Is curved three-dimensional ultrasound reconstruction needed to assess the warped pelvic floor plane?

OBJECTIVES

Caudal distension of the female pelvic floor is common and results in perineal descent and a caudally curved levator hiatus (warping). Image reconstruction of the pelvic floor using currently available ultrasound techniques involves a linear approach (flat-plane reconstruction). We aimed to evaluate the feasibility, reproducibility and potential usefulness of a new three-dimensional (3D) technique capable of reconstructing a curved plane of the levator hiatus.

METHODS

Primiparous women were recruited to undergo a 3D/four-dimensional transperineal ultrasound examination 3-6 months after delivery. Levator ani muscle warping was evaluated on Valsalva maneuver by measuring the distance between the plane extending from the pubic rami to the anorectal angle and the plane of minimal hiatal dimensions on the coronal plane. Warping distance was used to reconstruct a curved plane of the levator hiatus using the curved OmniView volume contrast imaging (VCI) technique (C-OV). Intra- and interobserver reproducibility of the C-OV technique were assessed, as was intermethod agreement between the C-OV technique and the linear OmniView-VCI (L-OV) technique, for the measurement of levator hiatal area on Valsalva maneuver.

RESULTS

Measurement of the levator hiatal area using C-OV was feasible in all 84 women recruited. The warping distance ranged from -3.5 to 9.7 mm, confirming that the 1-2-cm slice thickness traditionally used for linear reconstruction was adequate for proper assessment of levator hiatal area in our population. C-OV showed excellent intra- and interobserver reproducibility, as well as excellent agreement with the L-OV technique for measuring levator hiatal area. No systematic difference was demonstrated in any of the reproducibility studies performed.

CONCLUSIONS

3D reconstruction of the warped levator hiatal plane is feasible and highly reproducible. In our population, reconstruction of a curved plane to correct for levator hiatal warping did not offer any benefit over the traditionally performed linear reconstruction. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Is obstetric anal sphincter injury a risk factor for levator ani muscle avulsion in vaginal delivery?

OBJECTIVE

To analyze whether women who sustain obstetric anal sphincter injury (OASI) in their first vaginal delivery have a higher incidence of levator ani muscle (LAM) avulsion than do women without OASI.

METHODS

We conducted a prospective observational cohort study of 80 primiparous women who gave birth at our tertiary obstetric unit between September 2011 and July 2013. The women were divided into two groups: women diagnosed with OASI during vaginal delivery (n = 40) and women without OASI (n = 40), matched by mode of delivery and newborn birth weight. Four-dimensional (4D) transperineal ultrasound was performed in all participants at 6-12 months after delivery to assess for integrity or avulsion of the LAM. Ultrasound images were evaluated by two observers who were blinded to group assignment and clinical data. Interobserver agreement was assessed to determine the reproducibility of 4D transperineal ultrasound for diagnosing LAM avulsion.

RESULTS

We found no statistically significant differences between the two groups. The incidence of LAM avulsion was 24.3% in the OASI group and 34.2% in the control group (P = 0.448). Interobserver agreement in the diagnosis of LAM avulsion in the study population using 4D transperineal ultrasound was 89.5%, with a kappa index of 0.76.

CONCLUSIONS

Our findings do not support OASI as a risk factor for LAM avulsion. Prospective studies in larger populations are needed to establish the biomechanical relationships of the pelvic floor structures involved in vaginal delivery. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Pelvic floor health: a concept analysis

AIM

To report an analysis of the concept 'pelvic floor health'.

BACKGROUND

'Pelvic floor health' is a term used by multiple healthcare disciplines, yet as a concept is not well defined.

DESIGN

Rodger's evolutionary view was used to guide this analysis.

DATA SOURCES

Academic literature databases and public domain websites viewed via the Internet search engine Google.

REVIEW METHODS

Literature in English, published 1946-July 2014 was reviewed. Websites were accessed in May 2014, then analysed of presentation for relevance and content until data saturation. Thematic analysis identified attributes, antecedents and consequences of the concept.

RESULTS

Based on the defining attributes identified in the analysis, a contemporary definition is offered. 'Pelvic floor health' is the physical and functional integrity of the pelvic floor unit through the life stages of an individual (male or female), permitting an optimal quality of life through its multifunctional role, where the individual possesses or has access to knowledge, which empowers the ability to prevent or manage dysfunction.

CONCLUSION

This analysis provides a definition of 'pelvic floor health' that is based on a current shared meaning and distinguishes the term from medical and lay terms in a complex, multifaceted and often under-reported area of healthcare knowledge. This definition provides a basis for theory development in future research, by focusing on health rather than disorders or dysfunction. Further development of the meaning is required in an individual's social context, to ensure a contemporaneous understanding in a dynamic system of healthcare provision.

A new simple technique for 3-dimensional sonographic assessment of the pelvic floor muscles

OBJECTIVES

The purpose of this study was to assess the reproducibility of a new technique for 3-dimensional (3D) pelvic floor sonography: OmniView combined with Volume Contrast Imaging (VCI; GE Healthcare, Kretz Ultrasound, Zipf, Austria) for pelvic hiatal area measurement. In addition, we aimed to study the intermethod agreement between the new technique and the standard 3D rendering method.

METHODS

We acquired a static 3D sonographic transperineal volume from 124 nulliparous asymptomatic women and 118 women with symptoms of pelvic floor dysfunction. Each 3D data set was analyzed by the OmniView-VCI technique to measure the pelvic hiatal area twice by one operator and once by another to assess intraobserver and interobserver reproducibility. The first operator later measured the hiatal area using the 3D rendering method to evaluate intermethod agreement. Reproducibility and intermethod agreement were studied by the intraclass correlation coefficient and Bland-Altman method.

RESULTS

Hiatal area measurements by the OmniView-VCI technique showed high intraobserver and interobserver reproducibility in both asymptomatic and symptomatic women. In addition, high agreement was shown between the new technique and 3D rendering in both groups. No systematic differences were noted in any of the reliability studies performed. The new technique took slightly less time to calculate the hiatal area than the standard rendering method in both asymptomatic and symptomatic women.

CONCLUSIONS

OmniView-VCI is a reliable method for pelvic hiatal area measurement. Further studies are needed to assess its reliability under contraction and the Valsalva maneuver and to evaluate its usefulness and reproducibility for diagnosis of levator ani lesions.

Levator hiatus dimensions in late pregnancy and the process of labor: a 3- and 4-dimensional transperineal ultrasound study

OBJECTIVE

The objectives of the investigation were to study the association between levator hiatus dimensions in late pregnancy and both the length of second stage of labor and also the delivery mode in women delivering their first child.

STUDY DESIGN

In this cohort study, 231 nulliparous women were examined with 3- and 4-dimensional transperineal ultrasonography at 37 weeks of gestation. The anteroposterior, transverse diameter, and the area of levator hiatus were measured at rest, during levator ani muscle contraction, and during Valsalva maneuver. The second stage of labor was divided into passive and active second stage and delivery modes into normal vaginal or instrumental deliveries. Spearman correlation coefficient, independent-sample t test, and standard logistic regression were used for analysis.

RESULTS

Larger levator hiatus dimensions at rest and during contraction at 37 weeks of gestation correlated with a shorter duration of the active second stage in women with normal vaginal delivery (Spearman correlation coefficient, -0.13 to -0.35, P ≤ .08). Women having normal vaginal deliveries had significantly larger transverse diameter at rest, during contraction, and during Valsalva maneuver compared with women having instrumental deliveries (mean difference, 0.29; 95% confidence interval (CI), 0.16-0.41; mean difference, 0.33; 95% CI, 0.21-0.44 and mean difference, 0.24; 95% CI, 0.06-0.42; P < .05). The same was true for the levator hiatus area at rest and during contraction (mean difference, 1.22; 95% CI, 0.37-2.07 and mean difference, 0.84; 95% CI, 0.22-1.46; P < .01). These estimates were unchanged by adjustments in the logistic regression analysis.

CONCLUSION

Larger levator hiatus dimensions in late pregnancy had a significant association with a shorter active second stage of labor and normal vaginal delivery.

Learning process for performing and analyzing 3D/4D transperineal ultrasound imaging and interobserver reliability study

OBJECTIVES

To evaluate the learning process for acquiring three- and four-dimensional (3D/4D) transperineal ultrasound volumes of the levator hiatus (LH) dimensions at rest, during pelvic floor muscle (PFM) contraction and on Valsalva maneuver, and for analyzing the ultrasound volumes, as well as to perform an interobserver reliability study between two independent ultrasound examiners.

METHODS

This was a prospective study including 22 women. We monitored the learning process of an inexperienced examiner (IE) performing 3D/4D transperineal ultrasonography and analyzing the volumes. The examination included acquiring volumes during three PFM contractions and three Valsalva maneuvers. LH dimensions were determined in the axial plane. The learning process was documented by estimating agreement between the IE and an experienced examiner (E) using the intraclass correlation coefficient. Agreement was calculated in blocks of 10 ultrasound examinations and analyzed volumes. After the learning process was complete the interobserver reliability for the technique was calculated between these two independent examiners.

RESULTS

For offline analysis of the first 10 ultrasound volumes obtained by E, good to very good agreement between E and IE was achieved for all LH measurements except for the left and right levator-urethra gap and pubic arc. For the next 10 analyzed volumes, agreement improved for all LH measurements. Volumes that had been obtained by IE and E were then re-evaluated by IE, and good to very good agreement was found for all LH measurements indicating consistency in volume acquisition. The interobserver reliability study showed excellent ICC values (ICC, 0.81-0.97) for all LH measurements except the pubic arc (ICC = 0.67).

CONCLUSION

3D/4D transperineal ultrasound is a reliable technique that can be learned in a short period of time.