Reliability of new three-dimensional ultrasound technique for pelvic hiatal area measurement

Feasibility and reproducibility of new technique for measurement of transverse diameter of levator ani muscle hiatus using two-dimensional transperineal ultrasound in nulliparous women with term pregnancy

OBJECTIVES

The aim of the present study was two-fold. Firstly, we aimed to develop and describe a technique for measurement of the transverse diameter (TD) of the levator ani muscle (LAM) hiatus in the coronal view using two-dimensional (2D) transperineal ultrasound (TPUS) in nulliparous women with a term pregnancy. Secondly, we aimed to evaluate the feasibility and reproducibility of 2D-TPUS assessment of LAM hiatal TD and assess intermethod agreement between 2D-TPUS and three-dimensional (3D) TPUS measurement of TD in the axial plane, which is considered the gold standard in nulliparous women with term pregnancy.

METHODS

We recruited a group of nulliparous women with term pregnancy before the onset of labor. The study was conducted in two phases: Phase 1 involved developing and describing the 2D-TPUS technique for measuring LAM hiatal TD, and Phase 2 focused on assessing the technique's feasibility, reproducibility and intermethod agreement with 3D-TPUS measurement of LAM hiatal TD. In Phase 1, we enrolled 30 women. Each woman underwent acquisition of a 3D-TPUS volume, which was analyzed using multiplanar mode to identify and determine the appearance of the lateral borders of the LAM in the coronal plane, at the level of the plane of minimal hiatal dimensions. These borders were used as landmarks for TD measurement. Additionally, we measured the distance between the plane used for TD measurement and the center of the urethra in the axial view. In Phase 2, we recruited 100 women. Each woman underwent acquisition of three 2D-TPUS videoclips in the coronal plane, each encompassing a sweep of the entire LAM hiatus, and a 3D volume, all obtained during rest. On the 2D videoclips, TD was measured twice by one operator and once by another operator. In the 3D volume, TD was measured once, by one operator, in the axial plane; this measurement was considered the gold standard. Each operator was blinded to all other measurements during their assessments. We analyzed intraobserver and interobserver reproducibility and performed an intermethod (2D vs 3D) comparison. Bland-Altman analysis was conducted, and Levene's W0 test and Student's t-test were performed to explore clinical factors that might contribute to systematic differences.

RESULTS

In Phase 1, we identified successfully the landmarks denoting the lateral borders of the LAM hiatal TD in the coronal view. These appeared as two symmetrical hypoechogenic indentations located at the inner border of the hyperechogenic structure of the LAM, at the point of maximum distance between the two sides of the LAM. The distance between the urethra and the plane where TD should be measured using 3D-TPUS in the axial plane had a median of 4 mm and varied from 0 to 9 mm. This enabled us to describe a method for assessing LAM hiatal TD in the coronal plane using 2D-TPUS. In Phase 2, LAM hiatal TD was measured successfully in all 2D and 3D acquisitions from the entire group of 100 women. The analyses for intraobserver and interobserver reproducibility and the intermethod comparison (2D vs 3D) revealed almost perfect agreement in TD measurements using 2D-TPUS, with intraclass correlation coefficients of 0.95 (95% CI, 0.92-0.96), 0.87 (95% CI, 0.78-0.92) and 0.85 (95% CI, 0.78-0.90), respectively. The average differences between measurements were 0.1 mm for intraobserver, 1.0 mm for interobserver and 0.2 mm for intermethod repeatability. No systematic differences were observed in any of the measurement sets, except in the interobserver analysis, although this difference was clinically not significant (38.2 vs 37.2 mm, P = 0.01). None of the examined clinical factors (maternal body mass index and maternal age) exhibited a statistically significant impact on intraobserver, interobserver or intermethod reliability.

CONCLUSIONS

Utilizing our technique, described herein, to measure the LAM hiatal TD in the coronal view using 2D-TPUS is not only feasible but also highly reproducible and accurate in nulliparous women with term pregnancy. Moreover, it yields measurements that are comparable to those obtained in the reconstructed axial plane generated by 3D-TPUS. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.

Soft-tissue dystocia due to paradoxical contraction of the levator ani as a cause of prolonged second stage: concept, diagnosis, and potential treatment

Smaller pelvic floor dimensions seem to have been an evolutionary need to provide adequate support for the pelvic organs and the fetal head. Pelvic floor dimension and shape contributed to the complexity of human birth. Maternal pushing associated with pelvic floor muscle relaxation is key to vaginal birth. Using transperineal ultrasound, pelvic floor dimensions can be objectively measured in both static and dynamic conditions, such as pelvic floor muscle contraction and pushing. Several studies have evaluated the role of the pelvic floor in labor outcomes. Smaller levator hiatal dimensions seem to be associated with a longer duration of the second stage of labor and a higher risk of cesarean and operative deliveries. Furthermore, smaller levator hiatal dimensions are associated with a higher fetal head station at term of pregnancy, as assessed by transperineal ultrasound. With maternal pushing, most women can relax their pelvic floor, thus increasing their pelvic floor dimensions. Some women contract rather than relax their pelvic floor muscles under pushing, which is associated with a reduction in the anteroposterior diameter of the levator hiatus. This phenomenon is called levator ani muscle coactivation. Coactivation in nulliparous women at term of pregnancy before the onset of labor is associated with a higher fetal head station at term of pregnancy and a longer duration of the second stage of labor. In addition, levator ani muscle coactivation in nulliparous women undergoing induction of labor is associated with a longer duration of the active second stage of labor. Whether we can improve maternal pelvic floor relaxation with consequent improvement in labor outcomes remains a matter of debate. Maternal education, physiotherapy, and visual feedback are promising interventions. In particular, ultrasound visual feedback before the onset of labor can help women increase their levator hiatal dimensions and correct levator ani muscle coactivation in some cases. Ultrasound visual feedback in the second stage of labor was found to help women push more efficiently, thus obtaining a lower fetal head station at ultrasound and a shorter duration of the second stage of labor. The available evidence on the role of any intervention aimed to aid women to better relax their pelvic floor remains limited, and more studies are needed before considering its routine clinical application.

Validation of an automated software (Smartpelvic™) in assessing hiatal area from three dimensional transperineal pelvic volumes of pregnant women: comparison with manual analysis

OBJECTIVES

The aim of this investigation was to evaluate the agreement between a manual and an automatic technique in assessing levator hiatus area (LHA) during pregnancy from three-dimensional (3D) pelvic floor volumes obtained by trans-perineal ultrasound (TPUS).

METHODS

3D volumes were acquired during rest, maximum pelvic floor contraction and Valsalva maneuver from 66 pregnant women. Manual selection of LHA and automatic software (Smart Pelvic™) were applied on TPUS volume starting from a C-plane view. To evaluate intra- and inter-observer variability measurements of LHA were performed twice by the same operator and once by a second sonographer. Reference hiatal contours obtained manually by the first operator were compared with the automated ones. Reproducibility was evaluated by intraclass correlation coefficients (ICC) and Bland-Altman plots.

RESULTS

LHA measurement, using automatic software, achieved excellent intra-observer and inter-observer reproducibility in pregnant women both at rest and after dynamic analysis (ICC>0.9). Further, an excellent agreement resulted between manual selection of the LHA and automatic imaging (ICC>0.9). The average time taken to obtain LHA manually was significantly longer when compared to the automatic analysis (p≤0.0001).

CONCLUSIONS

Smart pelvic software resulted from a reliable method for automatically measuring the LHA, showing high reproducibility and accuracy.

Effects of Pelvic Floor Muscle Physiotherapy on Urinary, Bowel, and Sexual Functions in Women with Deep Infiltrating Endometriosis: A Randomized Controlled Trial

Background and Objectives: Endometriosis is a chronic and recurrent disease defined as the presence and proliferation of endometrial glands and stroma outside the uterine cavity. It affects up to 6-10% of women of reproductive age and can be classified into superficial, ovarian, and deep infiltrating endometriosis (DIE). Deep infiltrating endometriosis can be associated with pain symptoms and pelvic floor muscle hypertone. Moreover, it may be responsible of bowel, urinary, and sexual dysfunctions with impairment of women's quality of life. Few studies have investigated the role of physiotherapy in women with DIE. Here, we aimed first to evaluate the effects of pelvic floor physiotherapy (PFP) on urinary, bowel, and sexual functions. Secondly, we aimed to evaluate the effects of ultrasound visual feedback during PFP on pelvic floor and subjective modifications in the frequency of sexual intercourse. Materials and Methods: This randomized controlled trial was conducted between June 2018 and December 2019 at our tertiary center. Nulliparous women with DIE and superficial dyspareunia were enrolled. At first examination, levator hiatal area (LHA) assessed with 3D/4D transperineal ultrasound, pain symptoms, urinary, bowel, and sexual functions were evaluated. Then, women were randomly assigned to no intervention (control group) or treatment with five individual sessions of PFP (experimental group), and after four months women underwent a second examination. Urinary, bowel, and sexual functions were assessed with validated questionnaires at first and second examinations. In particular, the Bristol Female Lower Urinary Tract Symptoms questionnaire was used to evaluate urinary symptoms, the Knowles-Eccersley-Scott-Symptom questionnaire to assess the presence of constipation, and the Female Sexual Function Index to investigate sexual function. Study outcomes were the comparisons among groups in terms of differences in actual changes in median of questionnaire scores between first and second examinations. Results: Thirty women (17 in the experimental group and 13 in the control group) completed the study. No significant differences were found between the two groups regarding urinary, bowel, and sexual functions, although women in the experimental group showed a tendency towards an improvement in constipation symptoms. Conclusion: In women with DIE, PFP does not appear to affect urinary, bowel, and sexual functions. Therefore, despite the improvement in superficial dyspareunia, chronic pelvic pain, and PFM relaxation with high treatment satisfaction, women should be informed about the unclear impact of PFP on urinary, bowel, and sexual functions. Larger studies are necessary to further investigate the impact of PFP on these functions.

Is there a difference in pelvic floor muscle tone between women with and without pelvic pain? A systematic review and meta-analysis

BACKGROUND

Alterations in pelvic floor muscle (PFM) function have been observed in women with persistent noncancer pelvic pain (PNCPP) as compared with women without PNCPP; however, the literature presents conflicting findings regarding differences in PFM tone between women with and without PNCPP.

AIM

To systematically review the literature comparing PFM tone in women with and without PNCPP.

METHODS

MEDLINE, Embase, Emcare, CINAHL, PsycINFO, and Scopus were searched from inception to June 2021 for relevant studies. Studies were included that reported PFM tone data in women aged ≥18 years with and without PNCPP. The risk of bias was assessed with the National Heart, Lung, and Blood Institute Quality Assessment Tool. Standardized mean differences (SMDs) for PFM tone measures were calculated via random effects models.

OUTCOMES

Resting PFM tone parameters, including myoelectrical activity, resistance, morphometry, stiffness, flexibility, relaxation, and intravaginal pressure, measured by any clinical examination method or tool.

RESULTS

Twenty-one studies met the inclusion criteria. Seven PFM tone parameters were measured. Meta-analyses were conducted for myoelectrical activity, resistance, and anterior-posterior diameter of the levator hiatus. Myoelectrical activity and resistance were higher in women with PNCPP than in women without (SMD = 1.32 [95% CI, 0.36-2.29] and SMD = 2.05 [95% CI, 1.03-3.06], respectively). Women with PNCPP also had a smaller anterior-posterior diameter of the levator hiatus as compared with women without (SMD = -0.34 [95% CI, -0.51 to -0.16]). Meta-analyses were not performed for the remaining PFM tone parameters due to an insufficient number of studies; however, results of these studies suggested greater PFM stiffness and reduced PFM flexibility in women with PNCPP than in women without.

CLINICAL IMPLICATIONS

Available evidence suggests that women with PNCPP have increased PFM tone, which could be targeted by treatments.

STRENGTHS AND LIMITATIONS

A comprehensive search strategy was used with no restriction on language or date to review studies evaluating PFM tone parameters between women with and without PNCPP. However, meta-analyses were not undertaken for all parameters because few included studies measured the same PFM tone properties. There was variability in the methods used to assess PFM tone, all of which have some limitations.

CONCLUSION

Women with PNCPP have higher PFM tone than women without PNCPP; therefore, future research is required to understand the strength of the relationship between pelvic pain and PFM tone and to investigate the effect of treatment modalities to reduce PFM tone on pelvic pain in this population.

Three-Dimensional Ultrasound Evaluation of Pelvic Floor Muscle Contraction in Women Affected by Deep Infiltrating Endometriosis: Application of a Quick Contraction Scale

OBJECTIVES

Using transperineal 3D/4D ultrasound, we evaluated the prevalence of the various categories of a 4-point pelvic contraction scale among women affected by ovarian endometriosis (OE), deep infiltrating endometriosis (DIE), and healthy controls.

METHODS

This prospective study was conducted on nulliparous women scheduled for surgery to remove endometriosis, and nulliparous healthy volunteers who did not show any clinical or sonographic signs of endometriosis, who served as controls. Patients were subjected to 3D/4D transperineal ultrasound obtaining measurements of the antero-posterior diameter (APD), both at rest and during maximal pelvic floor muscle (PFM) contraction (PFMC). The difference of APD from rest to maximal PFMC was then calculated as percent change from baseline (ΔAPD) and patients were thus categorized using the 4-point pelvic contraction scale.

RESULTS

One hundred sixty-four patients were considered for the study. Mean difference in APD between relaxed state and maximal PFMC was 23.3 ± 7.9% (range 2.4-40.0) in controls, 20.5 ± 9.0% (range 0.0-37.3) in patients with OE, and 14.6 ± 10.4% (range 0.0-37.1) in patients with DIE (F-test = 19.5, P-value < .001). A significant negative correlation was found between the contraction scale and dyspareunia (rs = -0.17, P = .032), and it appeared to be stronger among patients with DIE (rs = -0.20, P = .076).

CONCLUSIONS

PFM function in endometriotic patients could be assessed reliably through this 4-point scale. The rapid identification of women suffering from PFM dysfunction, along with deep dyspareunia, could enable gynecologists to offer them additional therapies, such as PFM rehabilitation.

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?

Endometriosis: Epidemiology, Classification, Pathogenesis, Treatment and Genetics (Review of Literature)

Endometriosis is a “mysterious” disease and its exact cause has not yet been established. Among the etiological factors, congenital, environmental, epigenetic, autoimmune and allergic factors are listed. It is believed that the primary mechanism of the formation of endometriosis foci is retrograde menstruation, i.e., the passage of menstrual blood through the fallopian tubes into the peritoneal cavity and implantation of exfoliated endometrial cells. However, since this mechanism is also observed in healthy women, other factors must also be involved in the formation of endometriosis foci. Endometriosis is in many women the cause of infertility, chronic pain and the deterioration of the quality of life. It also represents a significant financial burden on health systems. The article presents a review of the literature on endometriosis—a disease affecting women throughout the world.

The maternal pelvic floor and labor outcome

Vaginal birth is the major cause of pelvic floor damage. The development of transperineal ultrasound has improved our understanding of the relationship between vaginal birth and pelvic floor dysfunction. The female pelvic floor dimensions and function can be assessed reliably in pregnant women. Maternal pushing associated with pelvic floor muscle relaxation is the central requirement of vaginal birth. Many studies have evaluated the role of the pelvic floor on labor outcomes. Smaller levator hiatal dimensions and incomplete or absent levator ani muscle relaxation seem to be associated with a longer duration of the second stage of labor and a higher risk of cesarean and operative deliveries. Here, we presented an overview of the current knowledge of the correlation between female pelvic floor dimension and function, as assessed by transperineal ultrasound, and labor outcome.

The correlation between transperineal ultrasound assessment of the levator ani muscle and postpartum urinary incontinence

AIMS

The primary aim of the present study was to assess the association between levator ani muscle (LAM) integrity and function on the one hand, and the risk of urinary incontinence (UI) on the other. A secondary objective was to assess the association between fundal pressure in the second stage of labor (Kristeller maneuver) and the risk of postpartum UI.

METHODS

In this prospective cohort study, women underwent a clinical and transperineal ultrasound examination at rest, at pelvic floor muscle contraction (PFMC), and at Valsalva maneuver 3-6 months after their first vaginal delivery. LAM avulsion and levator hiatal area (LHA) were evaluated. In addition, women were interviewed about the presence of UI, whether stress (SUI) or urgency (UUI).

RESULTS

Overall, data of 244 women were analyzed. SUI was reported in 50 (20.5%), while UUI was reported in 19 (7.8%) women. Women who reported SUI had a higher prevalence of LAM avulsion and less proportional reduction in LHA from rest to a maximum contraction in comparison to women with no SUI. Women who reported UUI had a greater LHA at rest, during contraction, and during maximal Valsalva in comparison to women without UUI. No significant association was found between the Kristeller maneuver and the incidence of any UI.

CONCLUSION

Levator ani avulsion and less proportional reduction of LHA with PFMC appear to be associated with a higher risk of postpartum urinary stress incontinence.

Assessment of levator hiatal area using 3D/4D transperineal ultrasound in women with deep infiltrating endometriosis and superficial dyspareunia treated with pelvic floor muscle physiotherapy: randomized controlled trial

OBJECTIVES

Deep infiltrating endometriosis (DIE) is associated with chronic pelvic pain, dyspareunia and pelvic floor muscle hypertonia. The primary aim of this study was to evaluate the effect of pelvic floor physiotherapy (PFP) on the area of levator ani hiatus during Valsalva maneuver, assessed using transperineal ultrasound, in women with DIE suffering from superficial dyspareunia.

METHODS

This was a randomized controlled trial of 34 nulliparous women diagnosed with DIE and associated superficial dyspareunia. After an initial clinical examination, all patients underwent three-dimensional/four-dimensional (3D/4D) transperineal ultrasound to measure the levator hiatal area (LHA) at rest, on maximum pelvic floor muscle contraction and on maximum Valsalva maneuver, and were asked to rate their pain symptoms using a numerical rating scale (NRS). Eligible women were assigned randomly (1:1 ratio) to no intervention (control group, 17 women) or treatment with five individual sessions of PFP (study group, 17 women). Four months after the first examination, all women underwent a second evaluation of pain symptoms and LHA on transperineal ultrasound. The primary outcome measure was the percentage change in LHA on maximum Valsalva maneuver between the baseline and follow-up examinations. The percentage changes in pain symptoms between the two examinations, including superficial and deep dyspareunia, dysmenorrhea, chronic pelvic pain, dysuria and dyschezia, were also evaluated.

RESULTS

Thirty women, comprising 17 in the study group and 13 in the control group, completed the study and were included in the analysis. The percentage change in LHA on maximum Valsalva maneuver between the two examinations was higher in the study group than in the control group (20.0 ± 24.8% vs -0.5 ± 3.3%; P = 0.02), indicating better pelvic floor muscle relaxation. After PFP treatment, the NRS score for superficial dyspareunia remained almost unchanged in the control group (median change in NRS (Δ-NRS), 0 (interquartile range (IQR), 0-0)) while a marked reduction was observed in the study group (median Δ-NRS, -3 (IQR, -4 to -2); P < 0.01). Moreover, there was a significant difference between the PFP and control groups with regards to the change in chronic pelvic pain (median Δ-NRS, 0 (IQR, -2 to 0) vs 0 (IQR, 0-1); P = 0.01).

CONCLUSIONS

In women with DIE, PFP seems to result in increased LHA on Valsalva maneuver, as observed by 3D/4D transperineal ultrasound, leading to improved superficial dyspareunia, chronic pelvic pain and pelvic floor muscle relaxation. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Brain views that benefit from three-dimensional ultrasound

PURPOSE OF REVIEW

Fetal central nervous system malformations are among the most common congenital anomalies. Whereas simple axial views are sufficient for basic fetal brain examination, other important views are essential for a more detailed examination, which are sometimes challenging to obtain. Three-dimensional ultrasound can be helpful in obtaining standardized and reproducible images of many difficult fetal brain views. The aim of the present review is to explore the most recent evidence on the utility and technique of three-dimensional ultrasound in the examination of the fetal brain, with particular emphasis on the brain views that benefit from three-dimensional ultrasound.

RECENT FINDINGS

The article describes the various techniques of acquisition and analyses of three-dimensional ultrasound volumes of the fetal brain and their usefulness in the assessment of normal and abnormal fetal brain anatomy. Three-dimensional ultrasound has also permitted the application of many new technologies, such as artificial intelligence and deep machine learning. Recently, thanks to high-quality three-dimensional ultrasound, fetal cortical development can be assessed quantitatively and reliably.

SUMMARY

Three dimensional ultrasound can help as a complementary tool to two-dimensional ultrasound in the assessment of the fetal brain development and malformations. In addition, it paves the way for the application of promising technologies in the evaluation of fetal brain.

VIDEO ABSTRACT

A video summarizing the findings of the article. The video illustrates the various approaches and techniques applied for the examination of the fetal brain using three-dimensional ultrasound. Furthermore, the advantages and future perspectives of the application of three-dimensional ultrasound in the examination of the fetal brain are discussed, http://links.lww.com/COOG/A74.

Transperineal ultrasound assessment of maternal pelvic floor at term and fetal head engagement

OBJECTIVES

To evaluate the association between pelvic floor dimensions in nulliparous women at term and fetal head engagement, as assessed by transperineal ultrasound.

METHODS

This was a prospective observational study of nulliparous women at term. Before the onset of labor, transperineal ultrasound was used to measure the anteroposterior diameter (APD) of the levator hiatus and the angle of progression (AoP) at rest, on maximum pelvic floor muscle contraction and on maximum Valsalva maneuver (before and after visual feedback). We assessed the correlation between pelvic floor static and dynamic dimensions (levator hiatal APD and levator ani muscle coactivation) and AoP, which is an objective index of fetal head engagement.

RESULTS

In total, 282 women were included in the analysis. Among these, 211 (74.8%) women had a vaginal delivery while 71 (25.2%) had a Cesarean delivery. AoP was narrower in the Cesarean-delivery group at rest, on maximum pelvic floor muscle contraction and on maximum Valsalva, whereas no differences in levator hiatal APD were found between the two groups. We found a negative correlation between levator hiatal APD at rest, on maximum pelvic floor muscle contraction and on maximum Valsalva and the duration of the second stage of labor. There was a positive correlation between AoP and levator hiatal APD on maximum Valsalva maneuver after visual feedback (r = 0.15, P = 0.01). Women with levator ani muscle contraction on Valsalva maneuver (i.e. coactivation), both pre and post visual feedback, had a narrower AoP at rest and on maximum Valsalva. After visual feedback, women with levator ani muscle coactivation had a longer second stage of labor than did those without (80.8 ± 61.4 min vs 62.9 ± 43.4 min (P = 0.04)).

CONCLUSIONS

Smaller pelvic floor dimensions and levator ani muscle coactivation are associated with higher fetal head station and with a longer second stage of labor in nulliparous women at term. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

The dynamic change of the anteroposterior diameter of the levator hiatus under Valsalva maneuver at term and labor outcome

AIM

The aim of the present study was to evaluate the correlation between the proportional change of anteroposterior diameter (APD) of levator hiatus from rest to maximum Valsalva maneuver in nulliparous women at term and labor outcome.

METHODS

We prospectively recruited nulliparous women at term before the onset of labor. Women underwent a two-dimensional transperineal ultrasound, measuring the APD of the levator hiatus at rest and under maximum Valsalva's maneuver. APD change from rest to maximum Valsalva was described both in terms of absolute figures and proportional change. Correlation of APD change with the mode of delivery and with labor durations was assessed.

RESULTS

Overall, 486 women were included in the analysis. No significant association between change in APD and the mode of delivery. We found a significant negative correlation between change of APD from rest to Valsalva and the duration of active second stage both in terms of absolute change (Pearson's r = -0.138, P = .009) and in terms of proportional change (Pearson's r = -0.154, P = .004). Survival outcomes based on Cox-regression model showed that APD was independently associated with the duration of active second stage of labor after adjusting for epidural analgesia, maternal age and body mass index (hazard ratio, 1.008; 95% confidence interval, 1.001-1.016; P = .04) CONCLUSION: Women with higher increase of the anteroposterior diameter of the levator hiatus from rest to Valsalva have a shorter active second stage of labor.

Transperineal Ultrasound Visual Feedback Assisted Pelvic Floor Muscle Physiotherapy in Women With Deep Infiltrating Endometriosis and Dyspareunia: A Pilot Study

A prospective study with the aim to evaluate the effects of pelvic floor physiotherapy was conducted among women with deep infiltrating endometriosis (DIE) and associated dyspareunia. At initial evaluation superficial and deep dyspareunia were assessed using a numerical rating scale, and levator hiatus area (LHA) was assessed with 3-D/4-D transperineal ultrasound. Women underwent five individual sessions of ultrasound visual feedback assisted pelvic floor physiotherapy. One month after the therapy, dyspareunia and LHA were reassessed and compared with pre-therapy data. Pelvic floor physiotherapy seems to improve both superficial and deep dyspareunia and pelvic floor muscle relaxation in women with DIE.

Effect of pelvic floor muscle training program in reducing postpartum levator hiatus area in Japanese women: A prospective cohort study using three-dimensional ultrasonography

AIM

To assess the effect of a pelvic floor muscle training (PFMT) program on postpartum levator hiatus area.

METHODS

A prospective cohort study was conducted at a clinic in Japan. Training and control groups were recruited from outpatient pregnant women at two separate time periods. Only the training group underwent the PFMT program, including education for home PFMT, home PFMT, and follow-up instructions. Education for home PFMT was held by 1 month postpartum to acquire the correct contraction of the pelvic floor muscle. Home PFMT was prescribed between 1 and 5 months postpartum; during this period, follow-up instructions were provided to keep the women motivated. Before and after home PFMT, the levator hiatus area was measured using ultrasonography.

RESULTS

In total, 44 women in the training group and 45 in the control group were analyzed. There were 36 women who reached a high adherence to three daily sets of home PFMT. The reduction in the levator hiatus area at rest was not statistically higher in the training group than that in the control group. For the subgroup with high adherence, the reduction in the area at rest was significantly higher by 4.43% in the training group than that in the control group (19.90% vs. 15.49%).

CONCLUSIONS

Although the PFMT program did not significantly reduce the postpartum levator hiatus area at rest, performing at least three sets of home PFMT each day significantly reduced the levator hiatus area by 4.43%.

CLINICAL TRIAL REGISTRATION

UMIN Clinical Trials Registry (ID; UMIN 000026188, Date; 17 February 2017).

Reliability and Diagnostic Accuracy of a New Vaginal Dynamometer to Measure Pelvic Floor Muscle Strength

AIMS

Assess the intrarater and interrater reliabilities and diagnostic accuracy of a new vaginal dynamometer to measure pelvic floor muscle (PFM) strength in incontinent and continent women.

METHODS

A test-retest reliability study including 152 female patients.

EXCLUSION CRITERIA

history of urge urinary incontinence, prolapse of pelvic organ, pregnancy, previous urogynecological surgery, severe vaginal atrophy, or neurological conditions. The examination comprised digital assessment using the modified Oxford scale (MOS) and dynamometry measurements with a new prototype hand-held dynamometer. The MOS score ranges from 0 to 5: 0, no contraction; 1, flicker; 2, weak; 3, moderate; 4, good; 5, strong. Examinations were performed by a physiatrist, a physiotherapist and a midwife. The rest period between each rater measurement was 5 minutes. Assessment of intrarater and interrater reliability was calculated with the intraclass correlation coefficient.

RESULTS

One hundred twenty-two incontinent women and 30 continent women were included. Scores between 0 and 2 in MOS were recorded in 72% of incontinent women versus 20% in continent patients (P < 0.001). Intrarater reliability of the dynamometer was 0.942 (95% confidence interval [CI], 0.920-0.958) and the interrater reliability was 0.937 (95% CI, 0.913-0.954). The analysis of variance analysis showed significant differences in PFM strength across digital assessment categories. The post-hoc analysis showed statistical differences between adjacent categories of MOS 1-2 and 2-3. The diagnostic accuracy showed an area under the curve of 0.82 (95% C,: 0.75-0.89), 0.87 (95% CI, 0.81-0.92), and 0.83 (95% CI, 0.77-0.90) for the physiatrist, midwife, and physiotherapist, respectively.

CONCLUSIONS

The results obtained show a good reliability and validity of this new vaginal dynamometer to quantify PFM strength.

Painful Love: Superficial Dyspareunia and Three Dimensional Transperineal Ultrasound Evaluation of Pelvic Floor Muscle in Women with Endometriosis

We conducted an observational study between March 2015 and March 2018 in our academic center. Symptomatic, sexually active women with clinical and sonographic diagnosis of deep infiltrating endometriosis (DIE) or isolated ovarian endometriosis were enrolled. Women were asked to rank endometriosis-related symptoms, especially superficial and deep dyspareunia. Moreover, 3D transperineal ultrasound was performed to assess the levator hiatus area (LHA) evaluating pelvic floor muscle (PFM) morphometry. Women with endometriosis seem to have a high prevalence of superficial dyspareunia and three-dimensional transperineal ultrasound seems to be a viable technique to assess PFM morphometry in these women.

Detection of Concealed Uterine Prolapse in the Volume-Rendering Mode of 4-Dimensional Translabial Ultrasound: A Retrospective Observational Study

OBJECTIVES

To assess the association between a widened vaginal canal on volume-rendered ultrasound (US) imaging with concealed uterine prolapse.

METHODS

This work was a retrospective study of 253 women who had an International Continence Society Pelvic Organ Prolapse Quantification System examination and translabial US examination. The anteroposterior diameter of the vaginal canal was measured in the rendered axial plane for all women. The widened vaginal canal was defined as an anteroposterior diameter above the 95th centile in women with normal uterine descent. The performance of the widened vaginal canal for prediction of clinical uterine prolapse was tested.

RESULTS

Valid data from 233 women were analyzed. A mean anteroposterior diameter of 5.6 mm (range, 2.3-10.5 mm; 95th percentile, 10 mm) was seen in 119 women with normal uterine descent. An eye-shaped vaginal canal with a mean anteroposterior diameter of 17.8 mm (range, 10.7-26.8 mm) was seen in 69 women with uterine prolapse. A widened vaginal canal was defined as an anteroposterior diameter of greater than 10 mm. Of 45 concealed uterine descents, 32 had a widened vaginal canal (ie, anteroposterior diameter > 10 mm), and 27 had clinical uterine prolapse. The κ test showed good agreement between physical and US findings (κ = 0.76; P < .001). Ultrasound findings had excellent predictive value (odds ratio, 82.3) for the diagnosis of clinical uterine prolapse.

CONCLUSIONS

An eye-shaped vaginal canal with an anteroposterior diameter of greater than 10 mm in the rendered axial plane was a sign of uterine prolapse. This sign may be helpful for detecting concealed uterine prolapse in complex pelvic organ prolapse.

Pelvic floor dysfunction at transperineal ultrasound and voiding alteration in women with posterior deep endometriosis

INTRODUCTION AND HYPOTHESIS

Posterior deep infiltrating endometriosis (DIE) has been associated with pelvic floor muscle (PFM) alteration and voiding dysfunction (VD). The aim of this study is to evaluate the correlation between the presence of VD and altered PFM morphometry, objectively evaluated using 3D/4D transperineal ultrasound at rest and during dynamic maneuvers, in patients with posterior DIE.

METHODS

A prospective study was conducted on 108 symptomatic women scheduled for surgical removal of posterior DIE. The study population was divided in two groups according to presence or absence of VD on the Bristol Female Lower Urinary Tract Symptoms (BFLUTS). A 3D/4D transperineal ultrasound was performed to compare the following PFM morphometric parameters: levator hiatus area (LHA), antero-posterior (AP) and left-right (LR) diameters and levator ani muscle (LAM) coactivation. LAM coactivation was defined as the paradoxical contraction of the pelvic floor muscle during the Valsalva maneuver causing a smaller LHA than in the resting state.

RESULTS

Forty-eight (45.2%) women presented VD, while 60 (54.8%) women did not report any voiding complaints. Baseline characteristics did not significantly differ between the two groups. We did not find any significant statistical differences in PFM parameters between the two groups, except for a higher rate of levator ani muscle coactivation in women with VD compared with women without VD [64.6% (31/48) versus 31.7% (19/60), respectively; p = < 0.001].

CONCLUSIONS

In women affected by posterior DIE, LAM coactivation at 3D/4D transperineal ultrasound seems to be more frequent in patients with than without VD.

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.

Contraction of the levator ani muscle during Valsalva maneuver (coactivation) is associated with a longer active second stage of labor in nulliparous women undergoing induction of labor

BACKGROUND

The Valsalva maneuver is normally accompanied by relaxation of the levator ani muscle, which stretches around the presenting part, but in some women the maneuver is accompanied by levator ani muscle contraction, which is referred to as levator ani muscle coactivation. The effect of such coactivation on labor outcome in women undergoing induction of labor has not been previously assessed.

OBJECTIVE

The aim of the study was to assess the effect of levator ani muscle coactivation on labor outcome, in particular on the duration of the second and active second stage of labor, in nulliparous women undergoing induction of labor.

STUDY DESIGN

Transperineal ultrasound was used to measure the anteroposterior diameter of the levator hiatus, both at rest and at maximum Valsalva maneuver, in a group of nulliparous women undergoing induction of labor in 2 tertiary-level university hospitals. The correlation between anteroposterior diameter of the levator hiatus values and levator ani muscle coactivation with the mode of delivery and various labor durations was assessed.

RESULTS

In total, 138 women were included in the analysis. Larger anteroposterior diameter of the levator hiatus at Valsalva was associated with a shorter second stage (r = -0.230, P = .021) and active second stage (r = -0.338, P = .001) of labor. Women with levator ani muscle coactivation had a significantly longer active second stage duration (60 ± 56 vs 28 ± 16 minutes, P < .001). Cox regression analysis, adjusted for maternal age and epidural analgesia, demonstrated an independent significant correlation between levator ani muscle coactivation and a longer active second stage of labor (hazard ratio, 2.085; 95% confidence interval, 1.158-3.752; P = .014). There was no significant difference between women who underwent operative delivery (n = 46) when compared with the spontaneous vaginal delivery group (n = 92) as regards anteroposterior diameter of the levator hiatus at rest and at Valsalva maneuver, nor in the prevalence of levator ani muscle coactivation (10/46 vs 15/92; P = .49).

CONCLUSION

Levator ani coactivation is associated with a longer active second stage of labor.

Fundal pressure in second stage of labor (Kristeller maneuver) is associated with increased risk of levator ani muscle avulsion

OBJECTIVE

To investigate the association between application of fundal pressure during the second stage of labor (Kristeller maneuver) and the risk of levator ani muscle (LAM) injury.

METHODS

This was a prospective case-control study of women recruited immediately after their first vaginal delivery in our university hospital between March 2014 and September 2016. Women who underwent the Kristeller maneuver were recruited as cases. For each case, a control (no Kristeller) was recruited matched for body mass index, use of epidural analgesia, duration of second stage of labor and birth weight. All women were invited to undergo four-dimensional (4D) transperineal ultrasound (TPU) 3-6 months postpartum. The main outcome measure was the presence of LAM avulsion on 4D-TPU. TPU results were compared between cases and controls. Multivariate logistic regression analysis was performed to identify independent risk factors for LAM avulsion.

RESULTS

During the study period, 134 women in the Kristeller maneuver group and 128 women in the control group underwent TPU assessment. Women who underwent the Kristeller maneuver had a higher prevalence of LAM avulsion than did controls (38/134 (28.4%) vs 18/128 (14.1%); P = 0.005). In addition, women in the Kristeller-maneuver group had a larger hiatal area on maximum Valsalva maneuver and a greater increase in hiatal area from rest to maximum Valsalva. On multivariate logistic regression analysis, use of the Kristeller maneuver was the only independent factor associated with LAM avulsion (odds ratio, 2.5 (95% CI, 1.29-4.51)).

CONCLUSION

The Kristeller maneuver is associated with an increased risk of LAM avulsion when applied in women during their first vaginal delivery. This should be taken into account when deciding to use fundal pressure to accelerate the second stage of labor and when counseling women following childbirth. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Morphometry of the nulliparous pelvic floor

OBJECTIVES

To describe morphometry of the pelvic floor in a large population of nulliparous women, comparing those with and those without pelvic pain. We also aimed to assess its association with characteristics such as age and body mass index (BMI).

METHODS

This was a prospective study performed between January 2013 and November 2015 in non-pregnant nulliparous women attending a general gynecology clinic. Following collection of demographic data, women were examined using translabial four-dimensional (4D) ultrasound. Dynamic volumes of pelvic floor muscle were obtained at rest, on maximal contraction and on Valsalva maneuver, and analyzed at a later date by an assessor blinded to demographic details. Standard measurements for each volume included levator hiatal area and anteroposterior and transverse diameters, and pubovisceral muscle length and width. Subanalysis was performed comparing women with and those without pelvic pain. Linear regression analysis was performed to assess the association between characteristics, including age and BMI, and levator hiatal area at rest.

RESULTS

Three hundred and sixty eight nulliparous women were examined using translabial 4D ultrasound. Median levator hiatal area was 10.62 cm² at rest, 11.95 cm² on Valsalva maneuver and 8.18 cm² on maximal contraction. There was no difference between women with and those without pelvic pain when comparing biometric measurements of the pelvic floor musculature, except for in pubovisceral muscle width during the contraction phase. Regression analysis demonstrated that higher age and BMI were associated with increased levator hiatal area measurement.

CONCLUSIONS

Pelvic floor morphometry in nulliparous women is unchanged by pelvic pain, but levator hiatal area is increased in women with higher BMI and age. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Diagnostic value of Omniview technique on the agenesis of corpus callosum

Objective: This study aimed to discuss the diagnostic value of Omniview technique on the agenesis of corpus callosum. Methods: A total of 43 pregnant women with no obvious structural abnormality and eight pregnant women who diagnosed with agenesis of corpus callosum (ACC) were included in this study. The 2D ultrasonography and the 3D ultrasonography Omniview technique were used to carry out ultrasonic examination on 43 normal fetuses and eight fetuses with agenesis of corpus callosum (as verified through magnetic resonance), respectively. Results: The Omniview technique visually displayed the median sagittal plane of the fetus. The ROC curve of Omniview (0.999) was much higher than that of 2D ultrasonography (0.817). Rating of ACC and normal fetuses showed that the diagnostic efficiency of 3D ultrasonography Omniview technique was much higher than 2D ultrasonography. Conclusion: 3D ultrasonography Omniview technique has certain advantage in the diagnosis of agenesis of corpus callosum, and is of great significance in the prenatal screening of callosum.

Pelvic floor muscle assessment on three- and four-dimensional transperineal ultrasound in women with ovarian endometriosis with or without retroperitoneal infiltration: a step towards complete functional assessment

OBJECTIVES

Previous studies comparing women with deep infiltrating endometriosis (DIE) and healthy controls have underlined an association between pelvic floor muscle (PFM) hypertonic dysfunction and deep lesions. The aim of this study was to compare the morphometry of PFM in women affected by ovarian endometriosis with DIE vs those without DIE in order to assess the impact of retroperitoneal infiltration by the disease on PFM function.

METHODS

This was a prospective study conducted between March 2015 and December 2016 on symptomatic women with a clinical and sonographic diagnosis of ovarian endometriosis with or without DIE, scheduled for laparoscopic surgery. We excluded patients with current or previous pregnancy, previous surgery for deep endometriosis, other causes of chronic pelvic pain or congenital or acquired abnormalities of pelvic floor anatomy. Three- and four-dimensional transperineal ultrasound was performed to evaluate PFM morphometry and assess levator hiatal area (LHA) and diameters at rest, during PFM contraction and during Valsalva maneuver. All volumes were analyzed offline by an investigator blinded to the clinical data.

RESULTS

One hundred and fourteen patients with ovarian endometriosis were enrolled in the study, 75 with DIE and 39 without DIE. The diagnosis of endometriosis was confirmed by histological examination in all patients. Compared with women without DIE, women with DIE showed a smaller LHA at rest, during contraction and during Valsalva maneuver (P = 0.03, P = 0.03 and P = 0.02, respectively) and a smaller reduction in LHA during PFM contraction (P = 0.04).

CONCLUSIONS

Women with ovarian endometriosis who were affected by DIE showed smaller hiatal dimensions than did women without DIE. Considering that PFM dysfunction in patients with DIE could cause pain symptoms and pelvic organ dysfunction, transperineal ultrasound could allow a more complete functional assessment and tailored therapy. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Pelvic floor muscle dysfunction on 3D/4D transperineal ultrasound in patients with deep infiltrating endometriosis: a pilot study

OBJECTIVE

Pelvic floor muscle (PFM) dysfunction seems to play an important role in the pathophysiology of pelvic pain, including that associated with deep infiltrating endometriosis (DIE). The aim of this study was to evaluate the static and dynamic morphometry of the PFM using three-dimensional (3D) and four-dimensional (4D) transperineal ultrasound in women with DIE compared with asymptomatic healthy women.

METHODS

This was a pilot, prospective study conducted at our tertiary center between March and November 2015. Fifty nulliparous women with DIE (study group) and 35 nulliparous asymptomatic healthy women (control group) were included. 3D/4D transperineal ultrasound examination of the PFM was performed in both groups. Levator hiatal area (LHA) and anteroposterior and left-right transverse diameters were evaluated at rest, on maximum PFM contraction and on maximum Valsalva maneuver. Persistent levator ani muscle (LAM) coactivation during Valsalva maneuver was investigated.

RESULTS

Compared with the control group, women with DIE had a smaller LHA at rest (P = 0.03) and during Valsalva maneuver (P < 0.01). Furthermore, reduction in LHA during PFM contraction (P < 0.001) and enlargement in LHA during Valsalva maneuver (P = 0.01) were significantly less marked. In comparison with controls, women with DIE presented a higher frequency of LAM coactivation during Valsalva maneuver, although this difference did not reach statistical significance (P = 0.05).

CONCLUSIONS

3D and 4D transperineal ultrasound is an objective and non-invasive method for PFM morphometry and may have a role in detecting PFM dysfunction in women with DIE. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Three-dimensional/four-dimensional transperineal ultrasound: clinical utility and future prospects

During the last decade, there has been a huge advancement in the use of transperineal ultrasound (TPU) in the field of obstetrics and gynecology. Its main applications in obstetrics include the monitoring of fetal progression in labor and recently the assessment of maternal pelvic dimensions, whereas in gynecology, TPU is at present widely used for the evaluation of the female pelvic floor, opening new boundaries for the assessment of pelvic floor disorders. The association of volumetric three-dimensional techniques has largely contributed to the remarkable progress that has occurred in the use of TPU. The aim of this paper is to offer an overview of the advantages, challenges and future perspectives of the use of TPU for women’s imaging.

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.

Warping of the levator hiatus: how significant is it?

OBJECTIVES

The levator hiatus is the largest potential hernial portal in the human body. Excessive distensibility is associated with female pelvic organ prolapse (POP). Distension occurs not just laterally but also caudally, resulting in perineal descent and hiatal deformation or 'warping'. The aim of this study was to quantify the warping effect in symptomatic women, to validate the depth of the rendered volume used for the 'simplified method' of measuring hiatal dimensions and to determine predictors for the degree of warping.

METHODS

This was a retrospective study utilizing records of patients referred to a tertiary urogynecological service between November 2012 and March 2013. Patients underwent a standardized interview, clinical assessment using the POP quantification system of the International Continence Society and four-dimensional translabial ultrasound. The craniocaudal difference in the location of minimal distances in mid-sagittal and coronal planes was determined by offline analysis of ultrasound volumes, and provided a numerical measure of warping. We tested potential predictors, such as demographic factors, signs and symptoms of prolapse, levator avulsion and levator distensibility, for an association with warping.

RESULTS

Full datasets were available for 190 women. The mean craniocaudal difference in location of minimal distances in mid-sagittal and coronal planes was -1.26 mm (range, -6.7 to 4.6 mm; P < 0.001). This measure of warping was associated with hiatal area on Valsalva maneuver (r = - 0.284; P < 0.0001) and signs of significant prolapse on clinical and ultrasound examination (both P < 0.0001).

CONCLUSIONS

The plane of minimal dimensions of the levator ani hiatus is non-Euclidean, i.e. warped, and the degree of warping is associated with hiatal distension, or 'ballooning', and with POP. However, the degree of warping is minor, the largest difference we found in the location of the plane of minimal dimensions being 6.7 mm. Hence, our results support the determination of hiatal area in a rendered volume of 1-2 cm in depth. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Agreement between two 3D ultrasound techniques for the assessment of the subpubic arch angle

OBJECTIVES

To assess the reliability of a new three-dimensional (3D) ultrasound technique for the measurement of the subpubic arch angle (SPA) and the agreement between two contrast-enhancing 3D ultrasound techniques.

METHODS

We acquired two static 3D transperineal volumes from 72 nulliparous women using two ultrasound machines equipped with two different 3D contrast enhancement and linear reconstruction softwares: 1. Oblique View Extended Imaging with HD-Volume Imaging (OVIX-HDVI™), Samsung; 2. Omniview with Volume Contrast Imaging (Omniview-VCI™), GE Healthcare. An operator measured SPA once by OVIX-HDVI, and twice by Omniview-VCI, while another operator measured SPA once by Omniview-VCI. We evaluated intra- and inter-observer reproducibility of Omniview-VCI and intermethod agreement. Reproducibility and intermethod agreement were studied by means of intraclass correlation coefficient (ICC) and Bland-Altman method.

RESULTS

Omniview-VCI SPA measurements showed excellent intraobserver and interobserver reproducibility (ICC 0.970; 95% C.I. 0.952 to 0.981, 0.932; 95% C.I. 0.893 to 0.957, respectively). Furthermore, Omniview VCI SPA measurements demonstrated excellent agreement with those performed by OVIX-HDVI technique (ICC 0.943; 95 C.I. 0.911 to 0.964). No systematic difference was found in any of the reliability studies.

CONCLUSIONS

OmniView-VCI is a reliable method for SPA assessment. Both OmniView-VCI and OVIX-HDVI can be used interchangeably for SPA measurement.

Subpubic Arch Angle and Mode of Delivery in Low-Risk Nulliparous Women

Objective: To assess whether subpubic arch angle (SPA) measurement before labor onset can predict labor outcome among low-risk pregnant women. Methods: 3D ultrasound volume was transperineally acquired from a series of nulliparous women with uncomplicated pregnancy at term before the onset of labor. SPA was measured offline using Oblique View Extended Imaging (OVIX) on each volume performed by an investigator not involved in the clinical management. Labor outcome was prospectively investigated in the whole study group. Results: Overall, 145 women were enrolled in the study. Of these, 83 underwent spontaneous vaginal delivery, whereas obstetric intervention was performed in 62 cases (Cesarean section in 40 and vacuum extraction in 22). The SPA appeared to be significantly narrower in the women submitted to obstetric intervention compared with those undergoing spontaneous vaginal delivery (116.8 ± 10.3° vs. 123.7 ± 9.6°, p < 0.01). At multivariate analysis SPA and maternal age were identified as independent predictors of the mode of delivery. On the other hand, the duration of labor did not show a significant relationship with SPA. Conclusions: In low-risk nulliparous women at term gestation, SPA measurement obtained by 3D ultrasound before the onset of labor seems to predict the likelihood of an obstetric intervention but not the duration of labor.