Racial differences in pelvic anatomy by magnetic resonance imaging

Assessment of the pelvic and body interface pressure during different recumbent and semi-recumbent birthing positions

BACKGROUND

Childbirth, a multifaceted physiological event, undergoes dynamic changes influenced significantly by the chosen birthing position, impacting comfort and maternal and neonatal outcomes among other factors. This study aimed to investigate the bed-body interface pressure across five commonly adopted birthing positions, particularly focusing on their influence on pelvic expansion biomechanics during labour.

METHODS

Twenty healthy participants, aged between 18 and 49 years, were evaluated. Interface pressure across multiple regions of interest, including the head, shoulder, pelvis, and full body, were meticulously assessed under different combinations of leg and back positioning.

FINDINGS

Significant variations in interface pressure were observed based on chosen positions. Post hoc pairwise comparisons showed different pressure distributions for all regions of interest, with the combination of legs in stirrups and a flat back resulting in the lowest average pressure in the pelvic region. During the closed glottis pushing task, this combination exhibited lower peak pressure and peak pressure index in the pelvic region compared to other positions.

INTERPRETATION

While upright positions are conventionally preferred, the study underscores the nuanced implications of recumbent and semi-recumbent positions. Although using stirrups with a flat back exerts less pressure, lying flat can impede blood flow and exacerbate pain, while stirrups might lead to discomfort and potential complications. Given these complexities, healthcare providers must consider multiple factors to determine optimal birthing positions. The interplay between birthing positions and obstetric outcomes awaits further exploration and refinement, marking an exciting frontier in maternal care.

Radiographic Assessment of Pelvic Inlet and Outlet View Angles in the Ethiopian Population

Background

Accurate radiographic assessment is pivotal in evaluating trauma patients with suspected pelvic ring disruptions. The conventional approach of using anteroposterior, 45° inlet, and 45° outlet radiographs for the evaluation of pelvic injury may not consistently align with varying lumbopelvic anatomy. This study aimed to determine the ideal pelvic inlet and outlet radiographic angles when there is limited access to advanced imaging (e.g., computed tomography [CT]) for assessing clinically relevant pelvic osseous landmarks and to investigate variations based on age, sex, and sacral dysmorphism.

Methods

This cross-sectional study investigated patients who were ≥18 years of age who had no traumatic injuries or pelvic ring pathology; we reviewed abdominopelvic CT scans that were obtained between January 1, 2023, and June 30, 2023. Midsagittal reconstruction and 3D rendering of 148 CT scans facilitated the measurement of pelvic inlet and outlet angles. Standard techniques that were based on previous studies were used to determine the ideal angles. Statistical analyses investigated mean pelvic inlet and outlet angles as well as correlations with age, sex, and sacral dysmorphism.

Results

The mean pelvic inlet angle was 23.8° ± 8.4° (95% confidence interval [CI]: 22.4° to 25.2°), and the mean outlet angle was 40.1° ± 5.9° (95% CI: 39.2° to 41.1°). Male patients exhibited greater inlet angles (27° versus 20°), whereas female patients had greater outlet angles (41° versus 39°). Pelves with dysmorphism showed a 3.6° increase in outlet angles when compared with those with normal sacral anatomy. An inverse relationship between age and inlet angle was observed.

Conclusions

This study highlights that the recommended 45° angle for pelvic inlet and outlet views may not optimally align with the anatomy of the Ethiopian population. The findings suggest that the ideal inlet and outlet angles for this population are 25° and 40°, respectively. Understanding these variations is crucial for optimizing pelvic radiographic views in trauma evaluation, potentially leading to more accurate assessments and improved patient care in this demographic.

Level of Evidence

Diagnostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Population affinity estimation using pelvic measurements based on computed tomographic data acquired from Japanese and Western Australian populations

The present study analyzes morphological differences in the pelvis of Japanese and Western Australian individuals and investigates the feasibility of population affinity classification based on computed tomography (CT) data. The Japanese and Western Australian samples comprise CT scans of 207 (103 females; 104 males) and 158 (78 females; 80 males) adult individuals, respectively. Following volumetric reconstruction, a total of 19 pelvic landmarks were obtained on each sample, and 11 measurements, including two angles, were calculated. Machine learning methods (random forest modeling [RFM] and support vector machine [SVM]) were used to classify population affinity. Classification accuracy of the two-way models was approximately 80% for RFM: the two-way sex-specific and sex-mixed models for SVM achieved > 90% and > 85%, respectively. The sex-specific models had higher accurate classification rates than the sex-mixed models, except for the Japanese male sample. The classification accuracy of the four-way sex and population affinity model had an overall classification accuracy of 76.71% for RFM and 87.67% for SVM. All the correct classification rates were higher in the Japanese relative to the Western Australian sample. Our data suggest that pelvic morphology is sufficiently distinct between Japanese and Western Australian individuals to facilitate the accurate classification of population affinity based on measurements acquired in CT images. To the best of our knowledge, this is the first study investigating the feasibility of population affinity estimation based on CT images of the pelvis, which appears as a viable supplement to traditional approaches based on cranio-facial morphology.

Disparities in Outcomes following Resection of Locally Advanced Rectal Cancer

Surgical margins following rectal cancer resection impact oncologic outcomes. We examined the relationship between margin status and race, ethnicity, region of care, and facility type. Patients undergoing resection of a stage II-III locally advanced rectal cancer (LARC) between 2004 and 2018 were identified through the National Cancer Database. Inverse probability of treatment weighting (IPTW) was performed, with margin positivity rate as the outcome of interest, and race/ethnicity and region of care as the predictors of interest. In total, 58,389 patients were included. After IPTW adjustment, non-Hispanic Black (NHB) patients were 12% (p = 0.029) more likely to have margin positivity than non-Hispanic White (NHW) patients. Patients in the northeast were 9% less likely to have margin positivity compared to those in the south. In the west, NHB patients were more likely to have positive margins than NHW patients. Care in academic/research centers was associated with lower likelihood of positive margins compared to community centers. Within academic/research centers, NHB patients were more likely to have positive margins than non-Hispanic Other patients. Our results suggest that disparity in surgical management of LARC in NHB patients exists across regions of the country and facility types. Further research aimed at identifying drivers of this disparity is warranted.

Quantitative 3D Analysis of Levator Ani Muscle Subdivisions in Nulliparous Women: MRI Feasibility Study

BACKGROUND

The levator ani muscle (LAM) is crucial for pelvic floor stability, yet its quantitative MRI assessment is only a recent focus. Our study aims to standardize the quantitative analysis of the LAM morphology within the 3D Pelvic Inclination Correction System (3D-PICS).

METHODS

We analyzed 35 static MR datasets from nulliparous women examining the pubovisceral (PVM), iliococcygeal (ICM), coccygeal (COC), and puborectal muscle (PRM). The PVM consists of three origin-insertion pairs, namely the puboanal (PAM), puboperineal (PPM) and pubovaginal muscle (PVaM). The analysis included a quantitative examination of the morphology of LAM, focusing on the median location (x/y/z) (x: anterior-posterior, y: superior-inferior, z: left-right) of the origin and insertion points (a), angles (b) and lengths (c) of LAM. Inter-rater reliability was calculated.

RESULTS

Interindividual variations in 3D coordinates among muscle subdivisions were shown. In all, 93% of all origin and insertion points were found within an SD of <8 mm. Angles to the xz-plane range between -15.4° (right PRM) and 40.7° (left PAM). The PRM is the largest pelvic muscle in static MRI. The ICC indicated moderate-to-good agreement between raters.

CONCLUSIONS

The accurate morphometry of the LAM and its subdivisions, along with reliable inter-rater agreement, was demonstrated, enhancing the understanding of normal pelvic anatomy in young nulliparous women.

Updating of pelvimetry standards in modern obstetrics

Clinical value of pelvimetry in modern obstetrics practices has never been established and normal values are set since the middle of the twentieth century. The aim of this study was to describe current dimensions of pelvis in a female French Caucasian population. A retrospective, bi-centric observational study was conducted from August 2013 to August 2019 in two French departments of Obstetrics. We included all Caucasian women who had a computed tomography pelvimetry during pregnancy. The primary outcome was the values of the obstetric transverse diameter, obstetric conjugate diameter and bispinous diameter. Five hundred and fifty-one CT pelvimetries were analyzed. The median Obstetric Transverse Diameter (OTD) was 12.41 cm and the 3rd percentile was 11 cm. The median Obstetric Conjugate Diameter (OCD) was 12.2 cm and the 3rd percentile was 10.5 cm. The median Bispinous Diameter (BSD) in our data collection was 10.9 cm and the 3rd percentile was 9.3 cm. A significant correlation coefficient between women's height and OTD, OCD and BSD was found. In our study, the OCD and the BSD have not evolved since the middle of the twentieth century. The obstetric transverse diameter was smaller than the standard currently used.

Hip and lumbosacral joint centre locations in asian population: Biases produced by existing regression equations and development of new equations

The hip and lumbosacral joint centre (HJC and LSJC) predictions are required to analyse the lumbo-pelvic-hip dynamics during various human motions. Some HJC and LSJC regression equations based on pelvic dimension have been developed; however, the pre-existing methods need to be re-evaluated, and methodological reconsideration may improve the regression methods. Here we show that pre-existing methods produce biased predictions of the LSJC and HJC in 23 male and 24 female Japanese adults, and that the biases in the LSJC differ between sexes, using magnetic resonance imaging (MRI) around the pelvis. Compared with directly measured locations on MRI, the pre-existing regression equations predict LSJC to be more posterior in males and more inferior and posterior in females, and HJC to be more medial in both sexes. The better pre-existing regression equation for LSJC height differs between sexes, with pelvic-width-base better in males and pelvic-depth-base better in females, respectively. We suggest the unsuitability of pre-existing methods to our dataset consisting of Japanese adults and the importance of considering sex differences in regression methods. We propose regression equations to predict HJC and LSJC, considering soft-tissue thickness, sex differences, and a height-directional measure, using least absolute shrinkage and selection operator regression. We validate them using leave-one-out cross-validation (LOOCV). LOOCV shows that our model produces negligible biases and smaller absolute errors than the pre-existing regressions; in particular, the anteroposterior absolute error for LSJC is less than half that of the pre-existing regression. Our regression equation can be a powerful solution for accurate motion analysis.

The association of maternal obesity and obstetric anal sphincter injuries at time of vaginal delivery

BACKGROUND

The risk of third- and fourth-degree perineal laceration after vaginal delivery in patients with obesity is relatively understudied and has mixed findings in existing literature.

OBJECTIVE

This study aimed to examine the association of maternal obesity and obstetric anal sphincter injuries at vaginal delivery.

STUDY DESIGN

The Healthcare Cost and Utilization Project's National Inpatient Sample was retrospectively queried to examine 7,385,341 vaginal deliveries from January 2017 to December 2019. The exposure assignment was obesity status. The main outcomes were third- and fourth-degree perineal lacerations after vaginal delivery. Statistical analysis examining the exposure-outcome association included (1) inverse probability of treatment weighting with log-Poisson regression generalized linear model to account for prepregnant and pregnant confounders for the exposure and (2) multinomial regression model to account for delivery factors in the inverse probability of treatment weighting cohort. The secondary outcomes included (1) the temporal trends of fourth-degree laceration and its associated factors at cohort level and (2) risk factor patterns for fourth-degree laceration by constructing a classification tree model.

RESULTS

In the inverse probability of treatment weighting cohort, patients with obesity were less likely to have fourth-degree lacerations and third-degree lacerations than patients without obesity (fourth-degree laceration: 2.3 vs 3.9 per 1000 vaginal deliveries, respectively; adjusted odds ratio, 0.62; 95% confidence interval, 0.56-0.69; third-degree laceration: 15.6 vs 20.1 per 1000 vaginal deliveries, respectively; adjusted odds ratio, 0.79; 95% confidence interval, 0.76-0.82). In contrast, in patients with obesity vs those without obesity, forceps delivery (54.7 vs 3.3 per 1000 vaginal deliveries, respectively; adjusted odds ratio, 17.73; 95% confidence interval, 16.17-19.44), vacuum-assisted delivery (19.8 vs 2.9 per 1000 vaginal deliveries, respectively; adjusted odds ratio, 5.18; 95% confidence interval, 4.85-5.53), episiotomy (19.2 vs 2.8 per 1000 vaginal deliveries, respectively; adjusted odds ratio, 3.95; 95% confidence interval, 3.71-4.20), and shoulder dystocia (17.8 vs 3.4 per 1000 vaginal deliveries, respectively; adjusted odds ratio, 2.60; 95% confidence interval, 2.29-2.94) were associated with more than a 2-fold increased risk of fourth-degree perineal laceration. Among the group with obesity, patients who had forceps delivery and shoulder dystocia had the highest incidence of fourth-degree laceration (105.3 per 1000 vaginal deliveries). Among the group without obesity, patients who had forceps delivery, shoulder dystocia, and macrosomia had the highest incidence of fourth-degree laceration (294.1 per 1000 vaginal deliveries). The incidence of fourth-degree perineal laceration decreased by 11.9% over time (P trend=.004); moreover, forceps delivery, vacuum-assisted delivery, and episiotomy decreased by 3.8%, 7.6%, and 29.5%, respectively (all, P trend<.05).

CONCLUSION

This national-level analysis suggests that patients with obesity are less likely to have obstetric anal sphincter injuries at the time of vaginal delivery. Furthermore, this analysis confirms other known risk factors for fourth-degree laceration, such as forceps delivery, vacuum-assisted delivery, episiotomy, and shoulder dystocia. However, we noted a decreasing trend in fourth-degree lacerations, which may be due to evolving obstetrical practices.

"Shortcuts" Causing Bias in Radiology Artificial Intelligence: Causes, Evaluation, and Mitigation

Despite the expert-level performance of artificial intelligence (AI) models for various medical imaging tasks, real-world performance failures with disparate outputs for various subgroups limit the usefulness of AI in improving patients' lives. Many definitions of fairness have been proposed, with discussions of various tensions that arise in the choice of an appropriate metric to use to evaluate bias; for example, should one aim for individual or group fairness? One central observation is that AI models apply "shortcut learning" whereby spurious features (such as chest tubes and portable radiographic markers on intensive care unit chest radiography) on medical images are used for prediction instead of identifying true pathology. Moreover, AI has been shown to have a remarkable ability to detect protected attributes of age, sex, and race, while the same models demonstrate bias against historically underserved subgroups of age, sex, and race in disease diagnosis. Therefore, an AI model may take shortcut predictions from these correlations and subsequently generate an outcome that is biased toward certain subgroups even when protected attributes are not explicitly used as inputs into the model. As a result, these subgroups became nonprivileged subgroups. In this review, the authors discuss the various types of bias from shortcut learning that may occur at different phases of AI model development, including data bias, modeling bias, and inference bias. The authors thereafter summarize various tool kits that can be used to evaluate and mitigate bias and note that these have largely been applied to nonmedical domains and require more evaluation for medical AI. The authors then summarize current techniques for mitigating bias from preprocessing (data-centric solutions) and during model development (computational solutions) and postprocessing (recalibration of learning). Ongoing legal changes where the use of a biased model will be penalized highlight the necessity of understanding, detecting, and mitigating biases from shortcut learning and will require diverse research teams looking at the whole AI pipeline.

Predictive value of the trans-perineal three-dimensional ultrasound measurement of the pubic arch angle for vaginal delivery

BACKGROUND

Numerous variables are linked to the success of vaginal delivery, including the subpubic arch angle (SPAA) during labor, the importance of which has not yet been fully elucidated.

AIM

To examine the SPAA distributional characteristics and to ascertain SPAA's ability to predict the type and duration of labor.

METHODS

We determined the SPAA and analyzed the corresponding data. We also evaluated the relationship between the SPAA and the mode of delivery and the duration of labor by regression. The present study comprised a total of 301 pregnant women who had given birth at Beijing Tiantan Hospital of the Capital Medical University between January and December of 2021.

RESULTS

Our analysis of 301 pregnant women revealed that the SPAA measured using three-dimensional trans-perineal ultrasound had a minimum angle of 81° and a maximum angle of 122.2°. The angle in the normal vaginal delivery group was greater than that in the labor cesarean group (P = 0.000). The SPAA was a highly significant positive predictor of normal vaginal delivery (P = 0.000) with an area under the curve of 0.782 (P = 0.000; 95%CI: 0.717-0.848). We found the length of the second stage of labor to be positively influenced by the SPAA using linear regression analysis (P = 0.045).

CONCLUSION

The SPAA was a highly significant positive predictor of normal vaginal delivery. The length of the second stage of labor and normal vaginal birth were predicted by SPAA.

Predictive value of the trans-perineal three-dimensional ultrasound measurement of the pubic arch angle for vaginal delivery

BACKGROUND

Numerous variables are linked to the success of vaginal delivery, including the subpubic arch angle (SPAA) during labor, the importance of which has not yet been fully elucidated.

AIM

To examine the SPAA distributional characteristics and to ascertain SPAA’s ability to predict the type and duration of labor.

METHODS

We determined the SPAA and analyzed the corresponding data. We also evaluated the relationship between the SPAA and the mode of delivery and the duration of labor by regression. The present study comprised a total of 301 pregnant women who had given birth at Beijing Tiantan Hospital of the Capital Medical University between January and December of 2021.

RESULTS

Our analysis of 301 pregnant women revealed that the SPAA measured using three-dimensional trans-perineal ultrasound had a minimum angle of 81° and a maximum angle of 122.2°. The angle in the normal vaginal delivery group was greater than that in the labor cesarean group (P = 0.000). The SPAA was a highly significant positive predictor of normal vaginal delivery (P = 0.000) with an area under the curve of 0.782 (P = 0.000; 95%CI, 0.717–0.848). We found the length of the second stage of labor to be positively influenced by the SPAA using linear regression analysis (P = 0.045).

CONCLUSION

The SPAA was a highly significant positive predictor of normal vaginal delivery. The length of the second stage of labor and normal vaginal birth were predicted by SPAA.

Racial and Ethnic Disparities in Pelvic Organ Prolapse Surgery in the United States: An Analysis of the ACS-NSQIP Clinical Registry

OBJECTIVE

To assess the types of POP surgery performed and patients' morbidity and mortality according to race and ethnicity in the United States.

METHODS

Using the American College of Surgeons National Surgical Quality Improvement Program database, we identified patients who had undergone POP procedures and stratified them by race and ethnicity. We compared differences in patient's baseline comorbidities and distribution of POP repairs performed. We further evaluated racial and ethnic disparities concerning complications, readmissions, reoperations, and mortality rates by performing univariate and multivariate analyses.

RESULTS

From 2012-2017, we identified 50,561 patients who underwent a primary POP repair procedure. The majority of patients were white (89.8%), followed by blacks (5.5%), and others (4.7%). Hispanics made up only 11.2% of the cohort. Black and Hispanic patients were younger, had higher BMI and suffered from a higher number of comorbidities than their white counterparts. There were significant differences in the types of POP procedures performed according to race and ethnicity. Despite no significant differences noted in overall complication rates, the types of complications varied by race and ethnicity. Neither race nor ethnicity was a significant predictor of reoperation or mortality.

CONCLUSION

There are notable racial and ethnic disparities in patients' comorbidities and types of POP repairs performed among women undergoing POP surgery in the United States. Although black patients are at a higher risk for readmission, there were no observed differences in complication, reoperation, or mortality rates according to race and ethnicity.

Hiatal failure: effects of pregnancy, delivery, and pelvic floor disorders on level III factors

INTRODUCTION AND HYPOTHESIS

The failure of the levator hiatus (LH) and urogenital hiatus (UGH) to remain closed is not only associated with pelvic floor disorders, but also contributes to recurrence after surgical repair. Pregnancy and vaginal birth are key events affecting this closure. An understanding of normal and failed hiatal closure is necessary to understand, manage, and prevent pelvic floor disorders.

METHODS

This narrative review was conducted by applying the keywords "levator hiatus" OR "genital hiatus" OR "urogenital hiatus" in PubMed. Articles that reported hiatal size related to pelvic floor disorders and pregnancy were chosen. Weighted averages for hiatal size were calculated for each clinical situation.

RESULTS

Women with prolapse have a 22% and 30% larger LH area measured by ultrasound at rest and during Valsalva than parous women with normal support. Women with persistently enlarged UGH have 2-3 times higher postoperative failure rates after surgery for prolapse. During pregnancy, the LH area at Valsalva increases by 29% from the first to the third trimester in preparation for childbirth. The enlarged postpartum hiatus recovers over time, but does not return to nulliparous size after vaginal birth. Levator muscle injury during vaginal birth, especially forceps-assisted, is associated with increases in hiatal size; however, it only explains a portion of hiatus variation-the rest can be explained by pelvic muscle function and possibly injury to other level III structures.

CONCLUSIONS

Failed hiatal closure is strongly related to pelvic floor disorders. Vaginal birth and levator injury are primary factors affecting this important mechanism.

Anatomical identification of ischial spines applicable to intrapartum transperineal ultrasound based on magnetic resonance imaging of pregnant women

OBJECTIVE

Intrapartum transperineal ultrasound is considered useful in judging fetal head descent; however, the inability to detect ischial spines on ultrasound images has been a drawback to its legitimacy. The current study aimed to determine the anatomical location of ischial spines, which can be directly applied to intrapartum transperineal ultrasound images.

METHOD

Based on magnetic resonance imaging (MRI) of 67 pregnant women at 33⁺² [31⁺⁶-34⁺⁰] weeks gestation (median [interquartile range: IQR]), we calculated the angle between the pubic symphysis and the midpoint of ischial spines (midline symphysis-ischial spine angle; mSIA), which is theoretically equivalent to the angle of progression at fetal head station 0 on ITU, by determining spatial coordinates of pelvic landmarks and utilizing spatial vector analysis. Furthermore, we measured symphysis-ischial spine distance (SID), defined as the distance between the vertical plane passing the lower edge of the pubic symphysis and the plane that passes the ischial spines.

RESULTS

As a result, mSIA was 109.6° [105.1-114.0] and SID 26.4 mm [19.8-30.7] (median, [IQR]). There was no correlation between mSIA or SID and maternal characteristics, including physique.

CONCLUSIONS

We established a novel method to measure the components of the pelvic anatomy by analyzing the three-dimensional coordinates of MRI data and identified the anatomical location of ischial spines which can be applied to ultrasound images. Our results provide valuable evidence to enhance the reliability of intrapartum transperineal ultrasound in assessing fetal head descent by considering the location of ischial spines.

Textbook typologies: Challenging the myth of the perfect obstetric pelvis

Medical education's treatment of obstetric-related anatomy exemplifies historical sex bias in medical curricula. Foundational obstetric and midwifery textbooks teach that clinical pelvimetry and the Caldwell-Moloy classification system are used to assess the pelvic capacity of a pregnant patient. We describe the history of these techniques-ostensibly developed to manage arrested labors-and offer the following criticisms. The sample on which these techniques were developed betrays the bias of the authors and does not represent the sample needed to address their interest in obstetric outcomes. Caldwell and Moloy wrote as though the size and shape of the bony pelvis are the primary causes of "difficult birth"; today we know differently, yet books still present their work as relevant. The human obstetric pelvis varies in complex ways that are healthy and normal such that neither individual clinical pelvimetric dimensions nor the artificial typologies developed from these measurements can be clearly correlated with obstetric outcomes. We critique the continued inclusion of clinical pelvimetry and the Caldwell-Moloy classification system in biomedical curricula for the racism that was inherent in the development of these techniques and that has clinical consequences today. We call for textbooks, curricula, and clinical practices to abandon these outdated, racist techniques. In their place, we call for a truly evidence-based practice of obstetrics and midwifery, one based on an understanding of the complexity and variability of the physiology of pregnancy and birth. Instead of using false typologies that lack evidence, this change would empower both pregnant people and practitioners.

Maternal education and racial/ethnic disparities in nulliparous, term, singleton, vertex cesarean deliveries in the United States

BACKGROUND

Racial and ethnic disparities in obstetrical and neonatal outcomes are prevalent in the United States. Such racial or ethnic disparities have also been documented in the prevalence of cesarean deliveries.

OBJECTIVE

We aimed to evaluate the impact of maternal education on racial or ethnic disparities in the prevalence of low-risk nulliparous, term, singleton, vertex cesarean deliveries in the United States.

STUDY DESIGN

This is a retrospective analysis of the Centers for Disease Control and Prevention live births database (2016–2019). Nulliparous, term, singleton, vertex births from the following racial/ethnic groups were included: non-Hispanic White, non-Hispanic Black, non-Hispanic Asian, and Hispanic. Pregnancies complicated by gestational or pregestational diabetes mellitus and hypertensive disorders were excluded. Data were analyzed on the basis of the level of maternal education (less than high school graduate, high school graduate, college graduate, and advanced degree). We compared the prevalence of cesarean deliveries among the different racial or ethnic groups within each education level using Pearson chi-square test with Bonferroni adjustment. Multivariate logistic regression was performed to assess the association between cesarean deliveries and maternal race/ethnicity, maternal education, and the interaction between maternal race or ethnicity and education level, while controlling for potential confounders. To demonstrate the effect of the interaction, separate logistic regression models with similar covariates were performed for each education level and for each race/ethnicity group. Statistical significance was determined as P<.05, and results were displayed as adjusted odds ratios with 95% confidence intervals.

RESULTS

The overall prevalence of cesarean deliveries during the study period was 23.4% (695,214 of 2,969,207 births). All racial or ethnic minority groups had higher rates of cesarean deliveries than non-Hispanic White women (non-Hispanic Black, 27.4%; non-Hispanic Asian, 25.6%; Hispanic, 23.0%; and non-Hispanic White, 22.4%; [P<.001 for all comparisons]). Similar racial or ethnic differences in cesarean delivery rates were detected among all education levels. Higher levels of education were associated with a lower likelihood of cesarean delivery (adjusted odds ratio, 0.88; [95% confidence interval, 0.87–0.89]) in women with advanced degrees than in women who did not graduate from high school. However, although maternal education was associated with a protective effect in non-Hispanic White and non-Hispanic Asian women (adjusted odds ratio, 0.83 [95% confidence interval, 0.81–0.85] and adjusted odds ratio, 0.81 [95% confidence interval, 0.77–0.86], respectively, for women with advanced degrees), it had a smaller protective effect in non-Hispanic Black women (adjusted odds ratio, 0.93 [95% confidence interval, 0.89–0.97]) and no protective effect in Hispanic women (adjusted odds ratio, 0.98 [95% confidence interval, 0.96–1.01]).

CONCLUSION

We document a significant racial/ethnic disparity in the prevalence of low-risk nulliparous, term, singleton, vertex cesarean deliveries in the United States. Furthermore, our findings suggest that although a higher level of maternal education is associated with a lower likelihood of cesarean delivery, this protective effect varies among racial or ethnic groups. Further research is needed to investigate the underlying causes for this racial/ethnic disparity.

Can Hip-Knee Line Angle Distinguish the Size of Pelvic Incidence?-Development of Quick Noninvasive Assessment Tool for Pelvic Incidence Classification

This study aimed to explore effective measurement angles for pelvic incidence (PI) classification and to develop a quick, noninvasive assessment tool for PI classification. We defined five variation types of hip–knee line (HKL) angles and tested the discrimination ability of the receiver operating characteristic (ROC) analysis using 125 photographs of upright standing posture from the right lateral side. ROC analysis revealed an applicable HKL angle defined by the line connecting the most raised part of the buttock and the central point of the knee and the midthigh line. The acceptable cut-off points for discriminating small or large PIs in terms of HKL angle were 18.5° for small PI (sensitivity, 0.91; specificity, 0.79) and 21.5° for large PI discrimination (sensitivity, 0.74; specificity, 0.72). In addition, we devised a quick noninvasive assessment tool for PI classification using the cut-offs of the HKL angle with a view to practical application. The results of intra- and inter-rater reliability ensured a substantial/moderate level of the tool (Cohen’s kappa coefficient, 0.79; Fleiss’s kappa coefficient, 0.50–0.54). These results revealed that the HKL angle can distinguish the size of the PI with a high/moderate discrimination ability. Furthermore, the tool indicated acceptable inter-/intra-rater reliability for practical applications.

Comparing the pelvis of Tibetan and Chinese Han women in rural areas of China: two population-based studies using coarsened exact matching

This study aims to investigate the difference of pelvic size and shape between Tibetan and Chinese Han women. Data on pelvic dimension measures including interspinous diameter (IS), intercrestal diameter (IC), external conjugate (EC) and transverse outlet (TO) were acquired from two population-based studies amongst Tibetan women in Lhasa, and Chinese Han women in Shaanxi province in China. After coarsened exact matching, there was no statistical difference between any characteristics amongst Tibetan and Chinese Han women (p>.05). The generalised estimating equation models showed Tibetan women had significantly lower IS and IC means than Chinese Han women (IS: 24.39 cm vs. 24.77 cm, p<.001; IC: 26.35 cm vs. 26.93 cm, p<.001) but statistically higher in TO mean (9.12 cm vs. 9.03 cm, p<.001). This study showed Tibetan women have smaller pelvis compared to Chinese Han women. This should offer a useful literature on the comparison of pelvis between Tibetan and Chinese Han women although the difference is small.Impact StatementWhat is already known on this subject? Previous studies in China indicated different populations have different dimensions of pelvis, with the pelvis of Uighur women being bigger than Chinese Han women, and that of Zhuang and Tu women being smaller than Chinese Han women. Little research reports the specific size of Tibetan women's pelvis. Living at high altitude, the Tibetan population have differentiated demographics and show local adaptions, such as unelevated haemoglobin, and significant catch-up growth for infants compared with Chinese Han infants. Therefore, there is a strong rationale for better understanding pelvic characteristics amongst this population.What the results of this study add? This study showed Tibetan women have smaller pelvises compared to Chinese Han women. Tibetan women have a smaller interspinous diameter and intercrestal diameter than Chinese Han women, which leads to relatively narrow hip.What the implications are of these findings for clinical practice and/or further research? This study provides useful comparative information on pelvic features between Tibetan and Chinese Han women although the findings of differences were small. In addition, during the formulation of women's health policy, the results of this study can provide data to support the selection of appropriate indicators of obstetrics and gynaecology for different populations of pregnant women during antenatal care and delivery.

Antenatal management and maternal/fetal outcomes associated with hyperglycaemia in pregnancy (HIP) in Uganda; a prospective cohort study

BACKGROUND

Hyperglycaemia in pregnancy (HIP) is associated with complications for both mother and baby. The prevalence of the condition is likely to increase across Africa as the continent undergoes a rapid demographic transition. However, little is known about the management and pregnancy outcomes associated with HIP in the region, particularly less severe forms of hyperglycaemia. It is therefore important to generate local data so that resources may be distributed effectively. The aim of this study was to describe the antenatal management and maternal/fetal outcomes associated with HIP in Ugandan women.

METHODS

A prospective cohort study of 2917 pregnant women in five major hospitals in urban/semi-urban central Uganda. Women were screened with oral glucose tolerance test (OGTT) at 24-28 weeks of gestation. Cases of gestational diabetes (GDM) and diabetes in pregnancy (DIP) were identified (WHO 2013 diagnostic criteria) and received standard care. Data was collected on maternal demographics, anthropometrics, antenatal management, umbilical cord c-peptide levels, and pregnancy outcomes.

RESULTS

Two hundred and seventy-six women were diagnosed with HIP (237 classified as GDM and 39 DIP). Women had between one and four fasting capillary blood glucose checks during third trimester. All received lifestyle advice, one quarter (69/276) received metformin therapy, and one woman received insulin. HIP was associated with large birthweight (unadjusted relative risk 1.30, 95% CI 1.00-1.68), Caesarean delivery (RR 1.34, 95% CI 1.14-1.57) and neonatal hypoglycaemia (RR 4.37, 95% CI 1.36-14.1), but not perinatal mortality or preterm birth. Pregnancy outcomes were generally worse for women with DIP compared with GDM.

CONCLUSION

HIP is associated with significant adverse pregnancy outcomes in this population, particularly overt diabetes in pregnancy. However pregnancy outcomes in women with milder forms of hyperglycaemia are similar to those with normoglycaemic pregnancies. Intervention strategies are required to improve current monitoring and management practice, and more research needed to understand if this is a cost-effective way of preventing poor perinatal outcomes.

Practical computer vision application to detect hip fractures on pelvic X-rays: a bi-institutional study

Background

Pelvic X-ray (PXR) is a ubiquitous modality to diagnose hip fractures. However, not all healthcare settings employ round-the-clock radiologists and PXR sensitivity for diagnosing hip fracture may vary depending on digital display. We aimed to validate a computer vision algorithm to detect hip fractures across two institutions’ heterogeneous patient populations. We hypothesized a convolutional neural network algorithm can accurately diagnose hip fractures on PXR and a web application can facilitate its bedside adoption.

Methods

The development cohort comprised 4235 PXRs from Chang Gung Memorial Hospital (CGMH). The validation cohort comprised 500 randomly sampled PXRs from CGMH and Stanford’s level I trauma centers. Xception was our convolutional neural network structure. We randomly applied image augmentation methods during training to account for image variations and used gradient-weighted class activation mapping to overlay heatmaps highlighting suspected fracture locations.

Results

Our hip fracture detection algorithm’s area under the receiver operating characteristic curves were 0.98 and 0.97 for CGMH and Stanford’s validation cohorts, respectively. Besides negative predictive value (0.88 Stanford cohort), all performance metrics—sensitivity, specificity, predictive values, accuracy, and F1 score—were above 0.90 for both validation cohorts. Our web application allows users to upload PXR in multiple formats from desktops or mobile phones and displays probability of the image containing a hip fracture with heatmap localization of the suspected fracture location.

Discussion

We refined and validated a high-performing computer vision algorithm to detect hip fractures on PXR. A web application facilitates algorithm use at the bedside, but the benefit of using our algorithm to supplement decision-making is likely institution dependent. Further study is required to confirm clinical validity and assess clinical utility of our algorithm.

Level of evidence

III, Diagnostic tests or criteria.

Iliac Bone Corridors to Host the Transiliac Internal Fixator-An Experimental CT Based Analysis

Background: The transiliac internal fixator (TIFI) is a novel minimally invasive surgical procedure to stabilize posterior pelvic ring fractures. Two bone corridors with different lengths, widths, and angulations are suitable to host screws in the posterior iliac wing. While the length and the width have been described previously, the angulation has not been determined yet. Methods: We created a computer tomography-based 3D-model of 40 patients (20 women, 20 men). The possible bone corridors to host the ilium screws for the TIFIcc (cranio-caudal) and the TIFIdv (dorso-ventral) procedure were identified. After reaching the optimal position, the angles in relation to the sagittal and axial plane were measured. The anterior pelvic plane was chosen as the reference plane. Results: The mean angle of the TIFIcc screws related to the axial plane was 63.4° (±1.8°) and to the sagittal plane was 12.3° (±1.5°). The mean angle of the TIFIdv screws related to the axial plane was 16.1° (±1.2°) and to the sagittal plane was 20.1° (±2.0°). In each group, a high constancy was apparent irrespective of the age or physical dimension of the patient, although a significant gender-dependent difference was observed”. Conclusions: Due to a high inter-individual constancy in length, width, and angulation, bone corridors in the posterior iliac wing are reliable to host screws for posterior pelvic ring fixation irrespective of each individual patient’s anatomy.

Does Vaginal Parity Alter the Association Between Symptoms and Signs of Pelvic Organ Prolapse?

OBJECTIVES

This study aimed to investigate whether the number of vaginal births a woman has alters the association between symptoms and signs of pelvic organ prolapse.

METHODS

In this retrospective study, we investigated data on 1748 women seen between April 2012 and January 2016. To elucidate whether the number of vaginal births is a confounder of this relationship, we used receiver operating characteristic statistics to investigate the association between symptoms and signs of prolapse in women of different vaginal parity.

RESULTS

A higher number of vaginal births was associated with a higher likelihood of symptoms of prolapse for any given degree of prolapse. Multivariate modeling, however, showed this confounding effect to be due to higher vaginal parity in older women (P < .001). Receiver operating characteristic curves obtained for the association between symptoms and signs of prolapse were near identical regardless of whether vaginal parity was included in the modeling. This was true for both clinical and imaging assessments of prolapse.

CONCLUSIONS

Although vaginal childbirth is associated with symptoms of prolapse, the number of vaginal births does not alter the relationship between symptoms and signs of prolapse among individuals presenting to a tertiary care center for evaluation. Previously published limits for "normal" pelvic organ mobility can be used irrespective of vaginal parity.

Fetal head malposition and epidural analgesia in labor: a case-control study

BACKGROUND

The fetal head malposition in labor leads to prolonged labor, cesarean delivery and increased perinatal morbidity. Epidural analgesia has been associated with fetal head malposition, but it remains unknown if this relation is causal.

OBJECTIVE

To compare the incidence of fetal malposition during labor and maternal/fetal outcomes, between women who received epidural analgesia with those who did not use the analgesic method.

STUDY DESIGN

Case control study including 500 women with a single fetus in vertex position who gave birth at term at the Policlinic Hospital of Modena between May 2019 and July 2019. Two-hundred and fifty women belonged to the epidural analgesia (EA) group and 250 to the control group.

RESULTS

The rate of posterior occiput positions occurred 4 times more frequently in the EA group than in the control group (8.8% vs 2.2%, p = .004). Cesarean sections were significantly higher in the EA group (11.6% vs 1.6%, p < .0000) as well as the need for augmentation with oxytocin (20% vs 8%, p = .0001) compared to the control group, in which spontaneous delivery prevailed instead. Women with epidural had labors that lasted on average 7.0 h against the 3.30 h of controls (p < .0000). The length of 2nd stage of labor was 55 vs 30 min (p = .009), respectively. No differences in blood loss and Apgar score between groups. Early breastfeeding was significantly higher among controls (82% vs 92.8%, p = .0004).

CONCLUSIONS

Women receiving epidural analgesia in labor have higher rate of fetal malposition, prolonged labors, and more cesarean sections than controls. However, further studies are required to confirm a causal association between EA and fetal head malposition.

Mediating Effects of Cardiometabolic Risk Factors on the Association Between Maternal Race-Ethnicity and Cesarean Delivery Among Low-Risk Women

Background: While racial-ethnic disparities in cesarean delivery rates among nulliparous women delivering a term singleton in the vertex position (NTSV) exist, it remains unclear the extent to which potentially modifiable maternal cardiometabolic risk factors (obesity, maternal hyperglycemia and hypertensive disorders) underlie these disparities. We examined race-ethnicity and risk of NTSV cesarean deliveries and whether the associations were mediated by maternal cardiometabolic risk factors. Materials and Methods: A cohort study of 62,048 NTSV deliveries in Kaiser Permanente Northern California. The outcome was cesarean delivery. Results: Black, Asian, and Hispanic women were at increased risk of having a NTSV cesarean delivery compared with White women (relative risks and 95% confidence intervals: 1.37 [1.28-1.45]; 1.11 [1.07-1.16]; 1.12 [1.07-1.16], respectively), independent of established risk factors and prenatal care utilization. The extent to which cardiometabolic risk factors mediated the associations between race-ethnicity (each group vs. White, in separate analyses) and NTSV cesarean delivery varied by race-ethnicity. Maternal overweight/obesity (body mass index ≥25.0) mediated the association between Black and Hispanic race-ethnicity and NTSV cesarean delivery (21.1% [15.8-26.4] and 24.7% [14.6-34.8, respectively), but not for Asian race. Maternal hyperglycemia (gestational diabetes mellitus or preexisting diabetes) mediated the association between Asian and Hispanic race and NTSV cesarean delivery (18.5% [9.8-27.2] and 9.8% [5.0-14.7], respectively), but not for Black race. Hypertensive disorders mediated 3.2% (0.70-5.8) of the association between Black race and cesarean delivery, but not for other race-ethnicities. Conclusion: Black, Asian, and Hispanic women are at increased risk for NTSV cesarean deliveries. Maternal cardiometabolic risk factors only partially mediate the associations between race-ethnicity and NSTV cesarean deliveries.

A missing distal complex of the external and internal anal sphincters: a macroscopic and histologic study using Japanese and German elderly cadavers

The lower margin of the internal anal sphincter (IAS) is considered to lie on a J-shaped, subcutaneous part (SCP) of the external anal sphincter (EAS). The lower IAS is united with the J-shaped SCP to form a smooth-striated muscle complex. In the first part of this study, we ensured the presence of the J-shaped EAS in the lateral wall of the anal canal from 12 near-term fetuses. Second, in the lateral anal wall, the examination of the longitudinal section from 20 male and 24 female Japanese cadavers (72-95 years-old) demonstrated that the J-shaped EAS was lost in 15 (34%) due to the very small SCP. Third, we demonstrated that the J-shaped EAS was restricted in the latera anal wall using longitudinal histological sections of the anal canal from 11 male Japanese cadavers (75-89 years-old). Therefore, a site-dependent difference in the IAS-EAS configuration was evident. Finally, we compared a frequency of the lost J-shape between human populations using 10 mm-thick frontal slices from 36 Japanese and 28 German cadavers. The two groups of cadavers were compatible in age (a 0.2-years' difference in males). The macroscopic observations revealed that the J-shaped EAS was absent from 13 (36%) Japanese and six (20%) German specimens, suggesting that the SCP degeneration occurred more frequent in elderly Japanese than elderly German individuals (p < 0.05). The distal IAS-EAS complex seemed to push residual feces out of the anal canal at a transient phase from evacuation to closure. The absence might be the first sigh of anal dysfunction.

Pelvic cross-sectional area at the level of the levator ani and prolapse

INTRODUCTION AND HYPOTHESIS

Intraabdominal pressure acts on the pelvic floor through an aperture surrounded by bony and muscular structures of the pelvis. A small pilot study showed the area of the anterior portion of this plane is larger in pelvic organ prolapse. We hypothesize that there is a relationship between prolapse and anterior (APA) and posterior (PPA) pelvic cross-sectional area in a larger, more diverse population.

STUDY DESIGN

MRIs from 30 prolapse subjects and 66 controls were analyzed in this case-control study. The measurement plane was tilted to approximate the level of the levator ani attachments. Three evaluators made measurements. Patient demographic characteristics were compared using Wilcoxon rank-sum and Fisher's exact tests. A multivariable logistic regression model identified factors independently associated with prolapse.

RESULTS

Controls were 3.7 years younger and had lower parity, but groups were similar in terms of race, height, and BMI. Cases had a larger APA (p < 0.0001), interspinous diameter (ISD) (p = 0.001), anterior-posterior (AP) diameter (p = 0.01), and smaller total obturator internus muscle (OIM) area (p = 0.002). There was no difference in the size of the PPA(p = 0.12). Bivariate logistic regression showed age (p = 0.007), parity (p = 0.009), ISD (p = 0.002), AP diameter (p = 0.02), APA (p < 0.0001), and OIM size (p = 0.01) were significantly associated with prolapse; however, PPA was not (p = 0.12). After adjusting for age, parity, and major levator defect, prolapse was significantly associated with increased anterior pelvic area (p = 0.001).

CONCLUSIONS

We confirm that a larger APA and decreasing OIM area are associated with prolapse. The PPA was not significantly associated with prolapse.

Risk factors associated with neonatal brachial plexus palsy in the United States

Neonatal brachial plexus palsy (NBPP) is a birth injury that can cause severe functional loss in the affected limb. The purpose of this study was to determine the temporal changes in the national incidence of this condition and whether associated risk factors have changed over time. Children born via vaginal delivery were identified in the Kids' Inpatient Database (KID) from 1997 to 2012, and those with NBPP were identified. The trend in incidence and risk factors were assessed through the study period. The nationwide incidence of NBPP decreased during the study period. Infants with shoulder dystocia, fetal macrosomia, and gestational diabetes had the highest risk of developing NBPP, while multiple birth mates during delivery had a protective effect. Multiple risk factors, including shoulder dystocia, macrosomia, and heavy for dates became less predictive of the development of NBPP over time. Several risk factors predispose children to the development of NBPP, and the effect of these risk factors has been changing. This information can guide obstetric treatment to help prevent NBPP. Level of evidence is diagnostic, level 3.

Obstetric fistulas in Uganda: scoping review using a determinant of health approach to provide a framework for health policy improvement

Background

The uneven global and national distribution of obstetric fistulas suggests a complex network of determinants contributing to fistula development. This study aims to create an understanding of the determinants of obstetric fistula in Uganda and to give a framework for health policy improvement.

Methods

A scoping review of existing literature was performed, searching the PubMed/MEDLINE database, Ugandan Demographic and Health Surveys, and official sources of Ugandan statistics. Data was analysed using the model for the determinants of health by Dahlgren and Whitehead.

Results

Obstetric fistulas are associated with different personal lifestyle factors, certain social and community networks, as well as poor working and living conditions. Malnutrition, early childbearing, limited female empowerment, lack of awareness of childbearing risks, low socioeconomic status, and long distances to emergency obstetric care play a part. Certain regions of Uganda are in particular associated with obstetric fistula, where an accumulation of determinants is notable.

Conclusion

Analysis using the model of Dahlgren and Whitehead shows that obstetric fistulas are associated with determinants at different levels of society. Poverty and low education link these in a web that is disproportionately hard to escape from for the poorest women. This inequity asks for co-operation between ministries to dismantle the environment for obstetric fistula.

First assessed cervical dilatation: is it associated with oxytocin augmentation during labour? A retrospective cohort study in a university hospital in Switzerland

OBJECTIVES

The primary objective of this study was to examine the association between the first assessed cervical dilatation in a labourward and the use of oxytocin augmentation during labour. Further analysis was performed by examining the actual stage of labour at the point oxytocin was first administered to those women.

DESIGN

Retrospective cohort study with the data collected from the medical records of the hospital.

SETTING

University Hospital Bern, Switzerland PARTICIPANTS: 1933 term nulliparous and multiparous women with a singleton pregnancy giving birth during the period June 2013 and May 2017, representing Robson groups 1 and 3.

MEASUREMENTS AND FINDINGS

Descriptive statistics and multivariable logistic regression models were performed. It was found that for the entire process of labour, nulliparous and multiparous women (n = 1933) with a first cervical dilatation of 5 or more cm were less likely to be augmented with oxytocin (OR 0.64, 95% CI 0.46; 0.88 and OR 0.56, 95% CI 0.38; 0.82, respectively) compared to women with a first cervical dilatation of less than 5 cm. Out of these augmented women (n = 746) having a first cervical dilatation of 5 or more cm, they had a lower likelihood of being augmented during the first stage of labour compared to women with a first cervical dilatation of less than 5 cm (OR 0.45, 95% CI 0.29; 0.7 for nulliparae and OR 0.32, 95% CI 0.16; 0.6 for multiparae). Additionally, it was observed that other factors contributed to the application of oxytocin. One such example was that epidural analgesia was associated with a high risk of oxytocin augmentation in nulliparae (OR 13.88, 95% CI 9.29; 20.74) and multiparae (OR 15.52, 95% CI 9.94; 24.22). The application of oxytocin was also found to affect the caesarean section rate in nulliparous and multiparous women as it was 20% and 13% respectively for those with oxytocin versus 13% and 4% respectively for those without oxytocin.

KEY CONCLUSIONS

Early admission to the labourward is associated with an increased use of oxytocin to augment labour, particularly, during the first stage of labour. Epidural analgesia is a main predictor for oxytocin augmentation in nulliparous and multiparous women.

IMPLICATIONS FOR PRACTICE

Pregnant women warrant more appropriate support during early labour, avoiding early maternal exhaustion and excessive obstetrical interventions.

Comparing intrapartum ultrasound and clinical examination in the assessment of fetal head position in African women

Introduction

We aimed to examine the agreement between intrapartum ultrasound and digital vaginal examination in assessing the occiput position in black African women who were in the first stage of labor and to evaluate the influence of ruptured membranes on this agreement.

Material and method

This was a cross-sectional study conducted in a teaching hospital in Ghana. Transabdominal ultrasound determination of the fetal head position was compared with digital vaginal examination of women in labor. The agreement between the two methods was examined with Cohen's kappa statistics.

Results

Altogether, 196 women in active labor were studied. The fetal head position could not be determined by digital vaginal examination in 62 cases (32%) while ultrasound could determine all. Moderate agreement (kappa = 0.4) was obtained in the 134 cases determined by both methods. Agreement on the occiput posterior position was very low (kappa = 0.1). Agreement on the occiput posterior position was not significantly different in ruptured versus intact membranes.

Conclusion

This study shows poor agreement between ultrasound and digital VE on the occiput posterior position in black African women who were in the first stage of labor. Again, over 85% of fetal head positions that could not be determined by digital vaginal examination were occiput transverse and posterior positions. This confirms that digital vaginal examination has difficulty in detecting malpositions, with no significant influence of intact or ruptured membranes. Ultrasound is therefore more useful than digital vaginal examination whenever malposition is suspected in the first stage of labor.

Association of race with anal incontinence in parous women

INTRODUCTION AND HYPOTHESIS

To investigate the relationship between race and anal incontinence (AI). Our hypotheses were (a) AI symptoms are similar between white and black women and (b) asymptomatic black and white women are equally likely to develop AI over one year of prospective observation.

METHODS

Parous women enrolled in a longitudinal cohort study were assessed for AI symptoms annually using Epidemiology of Prolapse and Incontinence Questionnaire. An AI score > 0 indicated any bother from AI; a score > 22.8 indicated clinically significant AI. We compared the odds of AI scores >0 at the visit level between white vs black women with logistic regression models using generalized estimating equations. We also estimated the odds of new AI symptoms at time T + 1(one year later) among women free of AI symptoms at time T comparing white vs black women. In the latter analysis, we considered new AI symptoms to be represented by scores above 11.4. Covariates included in the adjusted models were: mode of delivery, obstetrical anal sphincter injuries, body mass index, age at the first delivery, and parity at enrollment.

RESULTS

Among 1256 participants, 189 (15.0%) were black. AI score = 0 was observed at 74.2% (= 5122/6902) person-visits. The adjusted odds ratio of AI score > 0 was 1.83 (95% CI 1.24, 2.70) for white vs black women. Across 4364 visit pairs with AI score = 0 at time T, 203 (4.7%) had AI score > 11.4 at visit T + 1 and white race significantly increased the odds of developing symptoms at time T + 1 (adjusted OR = 2.26, 95% CI 1.28, 3.98).

CONCLUSIONS

In an analysis that controlled for mode of delivery, obstetrical anal sphincter injuries, obesity, age at first delivery, and parity, white race was significantly associated with AI symptoms at any point in time as well as to the development of AI over one year of observation.

A novel measurement of pelvic floor cross-sectional area in older and younger women with and without prolapse

BACKGROUND

An increase in size of the aperture of the pelvis that must be spanned by pelvic floor support structures translates to an increase in the force on these structures. Prior studies have measured the bony dimensions of the pelvis, but the effect of changes in muscle bulk that may affect the size of this area are unknown.

OBJECTIVES

To develop a technique to evaluate the aperture size in the anterior pelvis at the level of the levator ani muscle attachments, and to identify age-related changes in women with and without prolapse.

MATERIALS AND METHODS

This was a technique development and pilot case-control study evaluating pelvic magnetic resonance imaging from 30 primiparous women from the Michigan Pelvic Floor Research Group MRI Data Base: 10 younger women with normal support, 10 older women with prolapse, and 10 older menopausal women without prolapse. Anterior pelvic area measurements were made in a plane that included the bilateral ischial spines and the inferior pubic point, approximating the level of the arcus tendineus fascia pelvis. Measurements of the anterior pelvic area, obturator internus muscles, and interspinous diameter were made by 5 independent raters from the Society of Gynecologic Surgeons Pelvic Anatomy Group who focused on developing pelvic imaging techniques, and evaluating interrater reliability. Demographic characteristics were compared across groups of interest using the Wilcoxon rank sum test, χ2, or Fisher exact test where appropriate. Multiple linear regression models were created to identify independent predictors of anterior pelvic area.

RESULTS

Per the study design, groups differed in age and prolapse stage. There were no differences in race, height, body mass index, gravidity, or parity. Patients with prolapse had a significantly longer interspinous diameter, and more major (>50% of the muscle) levator ani defects when compared to both older and younger women without prolapse. Interrater reliability was high for all measurements (intraclass correlation coefficient = 0.96). The anterior pelvic area (cm2) was significantly larger in older women with prolapse compared to older (60 ± 5.1 vs 53 ± 4.9, P = .004) and younger (60 ± 5.1 vs 52 ± 4.6, P = .001) women with normal support. The younger and older women with normal support did not differ in anterior pelvic area (52 ± 4.6 vs 53 ± 4.9, P = .99). After adjusting for race and body mass index, increased anterior pelvic area was significantly associated with the following: being an older woman with prolapse (β = 6.61 cm2, P = .004), and interspinous diameter (β = 4.52 cm2, P = .004).

CONCLUSION

Older women with prolapse had the largest anterior area, suggesting that the anterior pelvic area is a novel measure to consider when evaluating women with prolapse. Interspinous diameter, and being an older woman with prolapse, were associated with a larger anterior pelvic area. This suggests that reduced obturator internus muscle size with age may not be the primary factor in determining anterior pelvic area, but that pelvic dimensions such as interspinous diameter could play a role. The measurements were highly repeatable. The high intraclass correlation coefficient indicates that all raters were able to successfully learn the imaging software and to perform measurements with high reproducibility.

Preliminary exploration of a quantitative assessment index for the matching performance of anatomical bone plates using computer

BACKGROUND

To explore a new quantitative index to assess the matching performance of anatomical bone plates using digital technology.

METHODS

CT data of normal tibias of 40 adults were collected. Two brands of medial distal tibia plates were digitized. Two trained orthopedists simulated the surgical operation in Rhino 5.1 software by placing the plate curve on the medial distal tibia surface. The volume of the interstice between the plate curve and the bone surface was measured. The inverse value of this average interstice distance was used as the matching performance index (MPI). A wall thickness analysis tool was used to mark various interstice distances with varied colors.

RESULTS

The Kangli medial distal tibia plate had a MPI of 0.55 ± 0.08 by operator A and 0.55 ± 0.06 by operator B. The general care medial distal tibia plate had a MPI of 0.32 ± 0.06 by operator A and 0.31 ± 0.05 by operator B. There were significant variations in the MPI between the two types of plates by both operators (p < 0.001). And significant variations were observed in the MPI of general care medial distal tibia plates among various operator groups (p = 0.028).

CONCLUSION

This quantitative index of matching performance is straightforward and intuitive. However, we still need a method to improve the experimental repeatability, especially when it comes to a plate with poor matching performance.

Pelvic organ prolapse in Caucasian and East Asian women: a comparative study

OBJECTIVE

Ethnicity has been suggested to be a significant risk factor for pelvic organ prolapse (POP); yet, pelvic organ descent in different ethnic groups, especially in Asian populations, is not well studied. The aim of this study was to compare prolapse stages, pelvic organ descent and hiatal dimensions between East Asian and Caucasian women presenting with symptoms of POP.

METHODS

This was a prospective observational study of East Asian and Caucasian women presenting with symptoms of POP to a tertiary urogynecology clinic in, respectively, Hong Kong and Sydney. Demographic data, prolapse symptoms and prolapse stage were assessed. Physical examination was performed using the pelvic organ prolapse quantification (POP-Q) system. All women underwent transperineal ultrasound using Voluson systems. Offline analysis of four-dimensional ultrasound volume data was performed at a later date, by one operator blinded to all clinical data, to ascertain pelvic organ descent and hiatal dimensions on Valsalva maneuver. Levator muscle avulsion was assessed in volumes obtained on pelvic floor muscle contraction. Multiple logistic regression analysis was performed to assess factors associated with prolapse on clinical and ultrasound examinations.

RESULTS

A total of 225 East Asian women were included between July 2012 and February 2014 from the Hong Kong clinic and 206 Caucasian women between January 2015 and July 2016 from the Sydney clinic. There was no significant difference in the overall staging of prolapse. However, in East Asian women, compared with Caucasians, apical compartment prolapse was more common (99.6% vs 71.8%, P < 0.001) and posterior compartment prolapse less common (16.9% vs 48.5%, P < 0.001) on POP-Q examination. On Valsalva maneuver, the position of the uterus was lower in East Asian than in Caucasian women (-11.3 vs 1.35 mm, P < 0.001), while the rectal ampulla position was lower in Caucasians than in East Asians (-10.6 vs - 4.1 mm, P < 0.001). On multiple regression analysis, Caucasian ethnicity was a significant factor for lower risk of apical compartment prolapse on clinical assessment (odds ratio (OR), 0.01; P < 0.001) and on ultrasound (OR, 0.13; P < 0.001), and for a higher risk of posterior compartment prolapse on clinical assessment (OR, 4.36; P < 0.001) and of true rectocele on ultrasound (OR, 8.14; P < 0.001).

CONCLUSIONS

East Asian women present more commonly with uterine prolapse while Caucasians show more often posterior compartment prolapse. Ethnicity was a significant predictor of type of prolapse on multivariate analysis. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Person-Centered Care for Patients with Pessaries

Pelvic organ prolapse is a common condition affecting women of any age but more likely to occur in the aging woman. Prolapse has a significant impact on quality of life, sexuality, and body image. Vaginal support pessaries have been used since ancient times and are a safe and effective nonsurgical treatment option. Fitting a pessary results in immediate symptom improvement. A comprehensive evaluation for pessary fitting is time intensive but necessary. Nurse providers perform direct pessary care and have a role in caring for women with prolapse expanding access to care. Caregiver and family involvement is important for pessary care and follow-up.

The much-awaited Venezia applicator: virtues of combined intracavitary and interstitial brachytherapy in locally advanced cervical cancer

Locally advanced cervix cancer is a major health problem in resource-limited areas of the world. Brachytherapy following pelvic chemoradiation is challenging, as large irregular clinical target volumes need adequate dose delivery while respecting limits of normal tissue tolerance. Achieving this is practically impossible using intracavitary brachytherapy alone. Consequently, combined intracavitary and interstitial brachytherapy provides higher chances of local control.

Pelvic and Lower Gastrointestinal Tract Anatomical Characterization of the Average Male

OBJECTIVE

Colorectal surgeons report difficulty in positioning surgical devices in males, particularly those with a narrower pelvis. The objectives of this study were to (1) characterize the anatomy of the pelvis and surrounding soft tissue from magnetic resonance and computed tomography scans from 10 average males (175 cm, 78 kg) and (2) develop a model representing the mean configuration to assess variability.

METHODS

The anatomy was characterized from existing scans using segmentation and registration techniques. Size and shape variation in the pelvis and soft tissue morphology was characterized using the Generalized Procrustes Analysis to compute the mean configuration.

RESULTS

There was considerable variability in volume of the psoas, connective tissue, and pelvis and in surface area of the mesorectum, pelvis, and connective tissue. Subject height was positively correlated with mesorectum surface area (P = .028, R² = 0.47) and pelvis volume ( P = .041, R² = 0.43). The anterior-posterior distance between the inferior pelvic floor muscle and pubic symphysis was positively correlated with subject height ( P = .043, r = 0.65). The angle between the superior mesorectum and sacral promontory was negatively correlated with subject height ( P = .042, r = -0.65). The pelvic inlet was positively correlated with subject weight ( P = .001, r = 0.89).

CONCLUSIONS

There was considerable variability in organ volume and surface area among average males with some correlations to subject height and weight. A physical trainer model created from these data helped surgeons trial and assess device prototypes in a controllable environment.

Human variation in the shape of the birth canal is significant and geographically structured

The human birth canal shows a tight fit with the size of the neonate, which can lead to obstetric complications. This is not the case in other apes, and has been explained as the outcome of conflicting evolutionary pressures for bipedal locomotion and parturition of a highly encephalized fetus. Despite the suggested evolutionary constraints on the female pelvis, we show that women are, in fact, extremely variable in the shape of the bony birth canal, with human populations having differently shaped pelvic canals. Neutral evolution through genetic drift and differential migration are largely responsible for the observed pattern of morphological diversity, which correlates well with neutral genetic diversity. Climatic adaptation might have played a role, albeit a minor one, with populations from colder regions showing a more transversally oval shape of the canal inlet. The significant extent of canal shape variation among women from different regions of the world has important implications for modern obstetric practice in multi-ethnic societies, as modern medical understanding has been largely developed on studies of European women.

Clinical and MRI changes of puborectalis and iliococcygeus after a short period of intensive pelvic floor muscles training with or without instrumentation : A prospective randomized controlled trial

PURPOSE

This study evaluates the impact of a 3-week period of intensive pelvic floor muscles training (PFMT), with or without instrumentation, on clinical and static magnetic resonance imaging (MRI) changes of puborectalis (PR) and iliococcygeus (IL) muscles.

METHODS

24 healthy young women were enrolled in the study and 17 achieved the 9 sessions of 30 min training exercises and conducted all assessments. Participants were randomly assigned in two training groups: voluntary contractions combined with hypopressive exercises (HYPO) or biofeedback exercises combined with transvaginal electrical stimulations (ELEC). Clinical and T2-weighted MRI assessments were realized before and after training.

RESULTS

Modified Oxford Grading System (MOGS) scores for left PR and perineal body significantly increased in the two groups (p = 0.039, p = 0.008), but MOGS score for right PR significantly increased only in HYPO (p = 0.020). Muscle volumes of right and left IL significantly decreased (p = 0.040, p = 0.045) after training as well as signal intensities of right and left PR (p = 0.040, p = 0.021) and thickness of right and left IL at mid-vagina location (p = 0.012, p = 0.011).

CONCLUSIONS

A short period of intensive PFMT induces clinical and morphological changes in PFMs at rest suggesting a decrease in IL volume and adipose content of PR. Although the results suggested that an intensive non-instrumented PFMT is as effective as an instrumented training, future controlled studies with greater sample sizes are needed to establish the relative and absolute effectiveness of each of the two interventions.

Ethnicity-related differences in inguinal canal dimensions between African and Caucasian populations and their potential impact on the mesh size for open and laparoscopic groin hernia repair in low-resource countries in Africa

Introduction

Access to surgery in Africa is significantly limited. Treatment outcomes in Africa differ significantly compared to those achieved in Europe or the US. Therefore, to popularise tension-free repair, it is essential to determine the economically justified mesh size for the African population.

Aim

To conduct anthropometric evaluation of the inguinal canal in African and European patients to determine its potential consequences for the mesh size for open and laparoscopic hernia repair.

Material and methods

The measurements were made in 44 adult males in Africa (group I) and were compared to measurements in 45 consecutive Caucasian males (group II). The mean age of patients was respectively 48.3 and 51.2 years.

Results

There was no statistically significant difference in the internal ring diameter between groups (2.2 vs. 2.1 cm; p = 0.58). The distance between the pubic tubercle and the inferomedial border of the internal inguinal ring was significantly shorter in group I (3.8 vs. 5.1 cm; p < 0.001). A similar difference was found in the length of transverse arch aponeurosis (2.9 vs. 4.0 cm; p < 0.001). The distance between the pubic tubercle and anterior superior iliac spine in group I was approximately 2 cm shorter on each side (10.0 vs. 11.8 cm; p < 0.001).

Conclusions

The anatomical differences in inguinal dimensions between Central African and European populations support the potential need to adjust the standard size of synthetic mesh used for hernia repair to the needs of local populations. The significantly smaller dimensions of the inguinal canal in African males may allow the use of smaller meshes.

Sonographic evaluation of the fetal spine position and success rate of manual rotation of the fetus in occiput posterior position: A randomized controlled trial

BACKGROUND

To evaluate whether sonographic (US) diagnosis of the fetal spine position could increase the success rate of manual rotation of the fetal occiput (MRFO) in second-stage arrest in persistent occiput posterior position (OPP).

METHODS

In this randomized controlled parallel single-center trial, 58 nulliparous in second-stage arrest of labor with fetus in cephalic presentation and OPP diagnosed by US were randomly assigned to group A where the fetal spine position was not known by the operator or to group B where the operator knew it. The main outcome was the success of MRFO in the two groups. Secondary outcomes were perineal injuries, blood loss, duration of expulsive period, and neonatal APGAR at 5 minutes.

RESULTS

A priori knowledge of the spine position improves the success of the MRFO (41.4% group A versus 82.8% group B, p value < 0.001), the percentage of spontaneous deliveries (27.6% group A versus 69% group B, p value = 0.01), and maternal outcome (intact perineum and blood loss). No differences were detected on the neonatal side.

CONCLUSIONS

MRFO is a safe and useful procedure that should be performed in second-stage arrest in OPP. A better performance was observed when supported by the US knowledge of the spine position. © 2017 Wiley Periodicals, Inc. J Clin Ultrasound 45:472-476, 2017.

Admixture mapping of pelvic organ prolapse in African Americans from the Women's Health Initiative Hormone Therapy trial

Evidence suggests European American (EA) women have two- to five-fold increased odds of having pelvic organ prolapse (POP) when compared with African American (AA) women. However, the role of genetic ancestry in relation to POP risk is not clear. Here we evaluate the association between genetic ancestry and POP in AA women from the Women’s Health Initiative Hormone Therapy trial. Women with grade 1 or higher classification, and grade 2 or higher classification for uterine prolapse, cystocele or rectocele at baseline or during follow-up were considered to have any POP (N = 805) and moderate/severe POP (N = 156), respectively. Women with at least two pelvic exams with no indication for POP served as controls (N = 344). We performed case-only, and case-control admixture-mapping analyses using multiple logistic regression while adjusting for age, BMI, parity and global ancestry. We evaluated the association between global ancestry and POP using multiple logistic regression. European ancestry at the individual level was not associated with POP risk. Case-only and case-control local ancestry analyses identified two ancestry-specific loci that may be associated with POP. One locus (Chromosome 15q26.2) achieved empirically-estimated statistical significance and was associated with decreased POP odds (considering grade ≥2 POP) with each unit increase in European ancestry (OR: 0.35; 95% CI: 0.30, 0.57; p-value = 1.48x10^-5). This region includes RGMA, a potent regulator of the BMP family of genes. The second locus (Chromosome 1q42.1-q42.3) was associated with increased POP odds with each unit increase in European ancestry (Odds ratio [OR]: 1.69; 95% confidence interval [CI]: 1.28, 2.22; p-value = 1.93x10^-4). Although this region did not reach statistical significance after considering multiple comparisons, it includes potentially relevant genes including TBCE, and ACTA1. Unique non-overlapping European and African ancestry-specific susceptibility loci may be associated with increased POP risk.

Can We Deliver Better?

Human childbirth has been described as an "obstetrical dilemma". Evolution favours enlargement of the foetal brain, whilst bipedal locomotion demands a reduction in pelvic breadth for improvements in biomechanical efficiency. The result of this conflict is a human pelvis incongruous with the dynamics of childbirth. Acute genital distortion at delivery can inflict lasting damage to female pelvic function. Pelvic organ prolapse, urinary, faecal incontinence and sexual dysfunction are long-term sequelae rarely discussed at antenatal care, impacting upon the expectant mother's ability to make an informed decision. The alternative option is the elective caesarean section, an abdominal incision bypassing the maladies of a vaginal delivery, although not without complications of its own. Childbirth remains an emotive event where evidence-based medicine can be disempowered, and the rising trend to "normalise" birth can disrupt care of the woman. This needs to be maintained in a healthy balance to best provide competent and safe care for women.

A sequential comparison of postoperative voiding function between two different transobturator sling procedures

INTRODUCTION

We evaluated sequential postoperative voiding function of two types of sling procedures (Monarc^® and ALIGN^®) in patients with stress urinary incontinence.

METHODS

Ninety-one women diagnosed with urodynamic stress incontinence were randomly assigned to the study. All enrolled patients underwent Monarc or ALIGN procedure. They were postoperatively evaluated at one day, one week, one month, three months, 12 months, and 24 months. The voiding function was evaluated with uroflowmetry and post-void residual urine. Patients were asked if voiding had changed after surgery and had to complete the incontinence quality of life scale (I-QoL) questionnaire at 12 months.

RESULTS

The Monarc (n=47) and ALIGN (n=44) groups had similar demographic characteristics. The maximal flow rate (Qmax) was significantly decreased on the first day after surgery and gradually increased during the following weeks. Comparing the two groups at one week, the ALIGN group had a significantly decreased Qmax than the Monarc group (17.6 ± 5.2 vs. 20.7 ± 5.0; p=0.004). However, at one, three, 12, and 24 months, there were no significant differences between the two groups.

CONCLUSIONS

This study demonstrated that an absorbable tensioning suture in the Monarc mesh could increase Qmax compared to ALIGN at one week after surgery. An absorbable tensioning suture may reduce the risk of an early postoperative voiding dysfunction compared to other meshes that do not have this.