Midline Angle Research Articles

Dystocia, Delivery, and Artificial Intelligence in Labor Management: Perspectives and Future Directions.

Labor management remains a critical issue in obstetrics, with dystocic labor presenting significant challenges in both management and outcomes. Recent advancements in intrapartum ultrasound have facilitated substantial progress in monitoring labor progression. This paper explores the integration of artificial intelligence (AI) into obstetric care, focusing on the Artificial Intelligence Dystocia Algorithm (AIDA) for assessing spatial dystocia during labor. The AIDA utilizes intrapartum ultrasonography to measure four geometric parameters: the angle of progression, the degree of asynclitism, the head-symphysis distance, and the midline angle. These measurements are analyzed using machine learning techniques to predict delivery outcomes and stratify risk. The AIDA classification system categorizes labor events into five classes, providing a nuanced assessment of labor progression. This approach offers several potential advantages, including objective assessment of fetal position, earlier detection of malpositions, and improved risk stratification, placing labor events within a broader context of labor dystocia and obstetric care and discussing their potential impact on clinical practice. This paper serves as a more comprehensive overview and discussion of the AIDA approach, its implications, perspectives, and future directions. However, challenges such as the technological requirements, training needs, and integration with clinical workflows are also addressed. This study emphasizes the necessity for additional validation across diverse populations and careful consideration of its ethical implications. The AIDA represents a significant advancement in applying AI to intrapartum care, potentially enhancing clinical decision-making and improving outcomes in cases of suspected dystocia. This paper explicates the key methodological approaches underpinning the AIDA, illustrating the integration of artificial intelligence and clinical expertise. The innovative framework presented offers a paradigm for similar endeavors in other medical specialties, potentially catalyzing advancements in AI-assisted healthcare beyond obstetrics.

AIDA (Artificial Intelligence Dystocia Algorithm) in Prolonged Dystocic Labor: Focus on Asynclitism Degree.

Asynclitism, a misalignment of the fetal head with respect to the plane of passage through the birth canal, represents a significant obstetric challenge. High degrees of asynclitism are associated with labor dystocia, difficult operative delivery, and cesarean delivery. Despite its clinical relevance, the diagnosis of asynclitism and its influence on the outcome of labor remain matters of debate. This study analyzes the role of the degree of asynclitism (AD) in assessing labor progress and predicting labor outcome, focusing on its ability to predict intrapartum cesarean delivery (ICD) versus non-cesarean delivery. The study also aims to assess the performance of the AIDA (Artificial Intelligence Dystocia Algorithm) algorithm in integrating AD with other ultrasound parameters for predicting labor outcome. This retrospective study involved 135 full-term nulliparous patients with singleton fetuses in cephalic presentation undergoing neuraxial analgesia. Data were collected at three Italian hospitals between January 2014 and December 2020. In addition to routine digital vaginal examination, all patients underwent intrapartum ultrasound (IU) during protracted second stage of labor (greater than three hours). Four geometric parameters were measured using standard 3.5 MHz transabdominal ultrasound probes: head-to-symphysis distance (HSD), degree of asynclitism (AD), angle of progression (AoP), and midline angle (MLA). The AIDA algorithm, a machine learning-based decision support system, was used to classify patients into five classes (from 0 to 4) based on the values of the four geometric parameters and to predict labor outcome (ICD or non-ICD). Six machine learning algorithms were used: MLP (multi-layer perceptron), RF (random forest), SVM (support vector machine), XGBoost, LR (logistic regression), and DT (decision tree). Pearson's correlation was used to investigate the relationship between AD and the other parameters. A degree of asynclitism greater than 70 mm was found to be significantly associated with an increased rate of cesarean deliveries. Pearson's correlation analysis showed a weak to very weak correlation between AD and AoP (PC = 0.36, p < 0.001), AD and HSD (PC = 0.18, p < 0.05), and AD and MLA (PC = 0.14). The AIDA algorithm demonstrated high accuracy in predicting labor outcome, particularly for AIDA classes 0 and 4, with 100% agreement with physician-practiced labor outcome in two cases (RF and SVM algorithms) and slightly lower agreement with MLP. For AIDA class 3, the RF algorithm performed best, with an accuracy of 92%. AD, in combination with HSD, MLA, and AoP, plays a significant role in predicting labor dystocia and labor outcome. The AIDA algorithm, based on these four geometric parameters, has proven to be a promising decision support tool for predicting labor outcome and may help reduce the need for unnecessary cesarean deliveries, while improving maternal-fetal outcomes. Future studies with larger cohorts are needed to further validate these findings and refine the cut-off thresholds for AD and other parameters in the AIDA algorithm.

Calculating curvature through gradient descent and nonlinear regression: A novel mathematical approach to digital anatomical morphometry

BackgroundAngular projection measurements have long been an established approach in anatomical morphometry. However, many described projection angles are in reference to inherently curved structures, often oversimplifying their topologies. AimsThe objective of this study is to develop a quick, quantitative method for determining structural curvature from digital images. We aim to utilize readily-available software and statistical methods to extrapolate curvature from images and compare this new method to established angular measurements. MethodsProjection angulation and curvature was modeled on and assessed by the acromia of 50 dry scapulae. Digital images were taken at a known scale, perpendicular to the acromion, and then processed with ImageJ software. Angles were measured by the angle tool and for curvature, seven markers were placed along the external and internal margins of the acromion. Utilizing Excel's Solver function, the coordinate points were passed through a rotation matrix and optimized for second order regression. Solver was instructed to minimize the sum of squared estimated error between our measured and calculated coordinate values by manipulating the angle of point rotation and regression equation coefficients. ResultsSignificant differences were found between external, internal, and midline acromion measurements in both angles and curvatures. External angle = 80.8 (14.2)°; internal angle = 130.3 (13.6)°; midline angle = 105.6 (10.5)°; [reported as mean (SD)]. External curvature = 0.055 (0.015) mm−1; internal curvature = 0.035 (0.025) mm−1; midline curvature = 0.046 (0.017) mm−1; [reported as median (IQR)]. ConclusionsSolver allows for researchers and clinicians to quickly characterize morphometric courses and properties of a given structure. Paired with other scalar measurements, curvature can complete the picture of an anatomical structure's pattern.

The head direction to the angle of progression ratio: a quantitative parameter for intrapartum evaluation of cephalic malposition

No previous study has evaluated the transitions of intrapartum transperineal ultrasound parameters during labor progression in cephalic malposition. We aimed to quantitate the characteristic trends of fetal head position and descent in cephalic malposition by analyzing the transitions of intrapartum transperineal ultrasound parameters and explore an indicator associated with the degree of cephalic malposition. We retrospectively analyzed pregnant women who delivered at term from January 2018 to December 2020 at the University of Tokyo Hospital. The fetal occipital position was classified as occiput anterior and nonocciput anterior according to the fetal occipital angle of 0° to 75° and 75° to 180°, respectively. Fetal occipital angle was defined by the midline angle and position of the ocular orbit. The differences in the trends of head direction, head-symphysis distance, and progression distance relative to the angle of progression between occiput anterior and nonocciput anterior cases were evaluated. In addition, the parameters that showed differences were analyzed to evaluate their relationship to the degree of cephalic malposition. A total of 502 images (occiput anterior, 319; nonocciput anterior, 183) met the inclusion criteria. The distribution of head direction values relative to the angle of progression was smaller in the nonocciput anterior group than in the occiput anterior group, whereas the head-symphysis distance and progression distance values relative to the angle of progression showed no difference in their distribution between the occiput anterior and nonocciput anterior groups. The ratio of head direction to the angle of progression was significantly smaller in the nonocciput anterior group than in the occiput anterior group (median [interquartile range], 0.03 [-0.02 to 0.10] vs 0.21 [0.12-0.28]; P<.0001). Furthermore, this ratio was negatively correlated with fetal occipital angle (Spearman correlation coefficient, -0.66). Our results indicated that the head direction to angle of progression ratio reflects the deviation in the fetal head direction toward the maternal dorsal side, and decreases in proportion to the degree of cephalic malposition. This concept of deviation in the head direction as an indicator for evaluating cephalic malposition with intrapartum transperineal ultrasound may contribute to improving labor management in the case of cephalic malposition.

Eligibility for minithoracotomy aortic valve replacement: from Van Praet classification to complex scanner measurements

Van Praet proposed a classification to predict the ease of minithoracotomy aortic valve replacement (MT-AVR) based on the position of the aorta in the thorax. We have evaluated the relevance of complex computed tomography (CT) scan measurements to predict the ease of performing a MT-AVR. The first 57 patients who underwent MT-AVR from February 2018 to June 2020 were selected prior to surgery using Van Praet's IA and IB classes. We made additional measurements on aorta position related to the chest and the incision on the preoperative CT scan. The main objective was to correlate complex CT measurements with different operating durations. Van Praet criteria were significantly related to the distance from the center of the aorta to the midline (p value < 0.001), the distance from the center of the aortic ring to the midline (p value = 0.013) and aorto-sternal angle (p < 0.001). We did not find a correlation between CT criteria and the different surgical steps durations in patients belonging to Van Praet classes IA and IB. Our cohort of Van Praet class Ia and Ib patients were able to benefit from a MT-AVR without the need for conversion. Complex CT measurements do not provide additional information to predict surgical difficulties. This classification appears to be sufficient to determine a patient's eligibility for MT-AVR, even for a surgeon experienced in sternotomy in his first MT-AVR.

Ecografía transperineal intraparto en la progresión del trabajo de parto

Objective: To determine the usefulness of intrapartum transperineal ultrasound in the progression of labor in patients admitted to the Concepción Palacios Maternity Parting Room Service, in the period May-August 2019. Methods: Prospective, descriptive and longitudinal study involving 98 patients. Transperineal ultrasound was performed every two hours during labor, evaluating cervical characteristics and changes in fetal head position and decline variety, linking them to clinical findings. Results: 219 ultrasounds were performed. At the begin, the ultrasound mean of the dilation was 5.94 x 1.70 cm and by clinic was 5.96 x 1.80 cm (p-0.717). At two hours, it was 8.14 x 1.92 cm and 8.15 x 2.07 cm, respectively (p-0.849). At the third control, it was 8.35 x 1.70 cm per ultrasound and by clinic it was 8.43 x 1.97 (p.0.604). With regard to erasure, among the 4 patients with grade 3 (the least erasure), 1 (25%) neck erased 40% - 50% and 3 (75%), 60% - 70%; 116 (100%) patients ultrasound as grade 0 (the maximum erasure), had a neck erased by more than 80%. There was an association between Hodge’s plane with the head-to-perineum distance (p-0.001) and the mid-line angle (p-0.001). There was no association with head-symphysis distance. Satisfaction was 100%. Conclusion: Intrapartum transperineal ultrasound is useful in evaluating the progression of labor. Keywords: Transperineal, Position variety, Fetal head descent.

Lateral and Frontal Cephalometric Measurements in a Cohort With Saethre-Chotzen Syndrome.

Descriptions of the craniofacial morphology in Saethre-Chotzen syndrome (SCS) are primarily based on case reports or visual assessments of affected families. The aim of this study was to compare cephalometric measurements of the craniofacial skeleton in a cohort of individuals with SCS and age- and sex-matched individuals without craniofacial anomalies. Retrospective case series. Eight girls and 4 boys with SCS (age range, 7.0-19.2 years). Cephalometric measurements were performed using lateral and frontal cephalograms. Most of the individuals with Saethre-Chotzen syndrome exhibited lower values for SNA, SNB, s-n and s-ar, while their NSL/NL, NSL/ML, NL/ML, and n-s-ba values were higher than the respective mean reference values for healthy individuals. In comparison with age- and sex-matched individuals without craniofacial anomalies, the individuals with SCS showed higher values for the maxillary and mandibular angular measurements, as well as for the menton midline angle. This sample of 12 unrelated individuals with SCS is the largest collected to date for cephalometric measurements. We found that the syndrome is associated with bimaxillary retrognathism, posterior maxillary and mandibular inclination, neutral sagittal relation as well as a tendency toward an open vertical skeletal relation, a short and flattened skull base, and facial asymmetry, as compared to individuals without the syndrome.

Intrapartum ultrasound during rotational forceps delivery: a novel tool for safety, quality control, and teaching

Operative vaginal delivery and, in particular, rotational forceps delivery require extensive training, specific skills, and dexterity. Performed correctly, it can reduce the need for difficult late second-stage cesarean delivery and its associated complications. When rotation to occiput anterior position is achieved, pelvic trauma and anal sphincter injury commonly associated with direct delivery from occiput posterior positions may be avoided. We report the original and novel use of real-time intrapartum ultrasound simultaneously during Kielland's rotational forceps delivery to monitor correct execution and increase maternal safety. This is a prospective observational study performed at the Charité University Hospital in Berlin between 2013 and 2018. Simultaneous, real-time, intrapartum suprapubic ultrasound during Kielland's rotational forceps deliveries were performed in a series of laboring women with normal fetuses and arrest of labor in the late second stage and with a fetal head malposition, requiring operative vaginal delivery. In addition to vaginal palpation for head station, rotation, and asynclitism, intrapartum ultrasound was also used to objectively determine head station, head direction, and midline angle. The operator was not blinded to the ultrasound findings. The delivering obstetrician examined the woman and performed the delivery. An assistant, trained in intrapartum ultrasound, placed a curved-array transducer transversely in the midline just above the pubic bone to display the forceps blades being applied and the rotation of the fetal head in occiput anterior position. In all 32 laboring women included in the study, the blades were applied correctly and the fetal heads successfully rotated to an occiput anterior position with direct ultrasound confirmation, and vaginal delivery was achieved. There were no cases of difficult application, repeat application, slippage of the blades, or rotation of the fetal head in the wrong direction. Maternal outcomes showed no vaginal tears, cervical tears, or postpartum hemorrhage >500 mL. There was 1 case of third-degree perineal tear (3a). Neonatal outcomes included mild hyperbilirubinemia (n=1), small cephalohematoma conservatively managed (n=1), and early-onset group B streptococcus sepsis secondary to maternal colonization (n=1). There were no neonatal deaths. Ultrasound guidance during Kielland's rotational forceps delivery is an original and novel approach. We describe the use of intrapartum ultrasound in assessing fetal head station and position and also to simultaneously and objectively monitor performance of rotational forceps delivery. Intrapartum ultrasound enhances operator confidence and, possibly, patient safety. It is a valuable adjunct to obstetrical training and can improve learning efficiency. Real-time ultrasound guidance of fetal head rotation to occiput anterior position with Kielland's forceps may also protect the perineum and reduce anal sphincter injury. This novel approach can lead to a renaissance in the safe use of Kielland's forceps.

Prediction of spontaneous vaginal delivery in nulliparous women with a prolonged second stage of labor: the value of intrapartum ultrasound

A limited number of studies have addressed the role of intrapartum ultrasound in the prediction of the mode of delivery in women with prolonged second stage of labor. The objective of the study was to evaluate the role of transabdominal and transperineal sonographic findings in the prediction of spontaneous vaginal delivery among nulliparous women with prolonged second stage of labor. This was a 2-center prospective study conducted at 2 tertiary maternity units. Nulliparous women with a prolonged active second stage of labor, as defined by active pushing lasting more than 120 minutes, were eligible for inclusion. Transabdominal ultrasound to evaluate the fetal head position and transperineal ultrasound for the measurement of the midline angle, the head-perineum distance, and the head-symphysis distance were performed in between uterine contractions and maternal pushes. At transperineal ultrasound the angle of progression was measured at rest and at the peak of maternal pushing effort. The delta angle of progression was defined as the difference between the angle of progression measured during active pushing at the peak of maternal effort and the angle of progression at rest. The sonographic findings of women who had spontaneous vaginal delivery vs those who required obstetric intervention, either vacuum extraction or cesarean delivery, were evaluated and compared. Overall, 109 were women included. Spontaneous vaginal delivery and obstetric intervention were recorded in 40 (36.7%) and 69 (63.3%) patients, respectively. Spontaneous vaginal delivery was associated with a higher rate of occiput anterior position (90% vs 53.2%, P < .0001), lower head-perineum distance and head-symphysis distance (33.2 ± 7.8 mm vs 40.1 ± 9.5 mm, P= .001, and 13.1 ± 4.6 mm vs 19.5 ± 8.4 mm, P < .001, respectively), narrower midline angle (29.6° ± 15.3° vs 54.2° ± 23.6°, P < .001) and wider angle of progression at the acme of the pushing effort (153.3° ± 19.8° vs 141.8° ± 25.7°, P= .02) and delta-angle of progression (17.3° ± 12.9° vs 12.5° ± 11.0°, P= .04). At logistic regression analysis, only the midline angle and the head-symphysis distance proved to be independent predictors of spontaneous vaginal delivery. More specifically, the area under the curve for the prediction of spontaneous vaginal delivery was 0.80, 95% confidence interval (0.69-0.92), P < .001, and 0.74, 95% confidence interval (0.65-0.83), P= .002, for the midline angle and for the head-symphysis distance, respectively. Transabdominal and transperineal intrapartum ultrasound parameters can predict the likelihood of spontaneous vaginal delivery in nulliparous women with prolonged second stage of labor.

Prediction of maxillary canine impaction based on panoramic radiographs.

ObjectivesThe objective of this article is to establish a large sample‐based prediction model for maxillary canine impaction based on linear and angular measurements on panoramic radiographs and to validate this model.Materials and methodsAll patients with at least two panoramic radiographs taken between the ages of 7 and 14 years with an interval of minimum 1 year and maximum 3 years (T1 and T2) were selected from the Department of Oral Health Sciences, University Hospital Leuven database. Linear and angular measurements were performed at T1. From 2361 records, 572 patients with unilateral or bilateral canine impaction were selected at T1. Of those, 306 patients were still untreated at T2 and were used as study sample. To construct the prediction model, logistic regression analysis was used.ResultsThe parameters analyzed through backward selection procedure were canine to midline angle, canine to first premolar angle, canine cusp to midline distance, canine cusp to maxillary plane distance, sector, quadratic trends for continuous predictors, and all pairwise interactions. The final model was applied to calculate the likelihood of impaction and yielded an area under the curve equal to 0.783 (95% CI [0.742–0.823]). The cut‐off point was fixed on 0.342 with a sensitivity of 0.800 and a specificity of 0.598. The cross‐validated area under the curve was equal to 0.750 (95% CI [0.700, 0.799]).ConclusionThe prediction model based on the above mentioned parameters measured on panoramic radiographs is a valuable tool to decide between early intervention and regular follow‐up of impacted canines.

A simple model to predict the complicated operative vaginal deliveries using vacuum or forceps

Complicated operative vaginal deliveries are associated with high neonatal morbidity and maternal trauma, especially if the procedure is unsuccessful and a cesarean delivery is needed. The decision to perform an operative vaginal delivery has traditionally been based on a subjective assessment by digital vaginal examination combined with the clinical expertise of the obstetrician. Currently there is no method for objectively quantifying the likelihood of successful delivery. Intrapartum ultrasound has been introduced in clinical practice to help predict the progression and final method of delivery. The aim of this study was to compare predictive models for identifying complicated operative vaginal deliveries (vacuum or forceps) based on intrapartum transperineal ultrasound in nulliparous women. We performed a prospective cohort study in nulliparous women at term with singleton pregnancies and full dilatation who underwent intrapartum transperineal ultrasound evaluation prior to operative vaginal delivery. Managing obstetricians were blinded to the ultrasound data. Intrapartum transperineal ultrasound (angle of progression, progression distance, and midline angle) was performed immediately before instrument application, both at rest and concurrently with pushing. Intrapartum evaluation of fetal biometric parameters (estimated fetal weight, head circumference, and biparietal diameter) was also carried out. An operative vaginal delivery was classified as complicated when 1 or more of the following complications occurred: ≥3 tractions needed; third- to fourth-degree perineal tear; severe bleeding during episiotomy repair (decrease of ≥2.5 g/dL in the hemoglobin level); or significant traumatic neonatal lesion (subdural-intracerebral hemorrhage, epicranial subaponeurotic hemorrhage, skeletal injuries, injuries to spine and spinal cord, or peripheral and cranial nerve injuries). Six predictive models were evaluated (information available in Table2). We recruited 84 nulliparous patients, of whom 5 were excluded because of the difficulty of adequately evaluating the biparietal diameter and head circumference. A total of 79 nulliparous patients were studied (47 vacuum deliveries, 32 forceps deliveries) with 13 cases in the occiput-posterior position. We identified 31 cases of complicated operative vaginal deliveries (19 vacuum deliveries and 12 forceps deliveries). No differences were identified in obstetric, neonatal, or intrapartum characteristics between the 2 study groups (operative uncomplicated vaginal delivery vs operative complicated vaginal delivery), with the following exceptions: estimated fetal weight (3243 ± 425 g vs 3565 ± 330 g; P= .001), biparietal diameter (93.2 ± 2.1 vs 95.2 ± 2.3 mm; P= .001), head circumference (336 ± 12 vs 348 ± 6.4 mm; P= .001), sex (female 62.5% vs 29.0%; P= .010), newborn weight (3258 ± 472 g vs 3499 ± 383 g; P= .027), and number of tractions (median, interquartile range) (1 [1-2] vs 4 [3-5]; P < .0005). To predict complicated operative deliveries, all 6 of the studied models presented an area under the receiver-operating characteristics curve between 0.863 and 0.876 (95% confidence intervals, 0.775-0.950 and 0.790-0.963; P < .0005). The results of the study met the criteria of interpretability and parsimony (simplicity), allowing us to identify a binary logistic regression model based on the angle of progression and head circumference; this model has an area under the receiver-operating characteristics curve of 0.876 (95% confidence interval, 0.790-0.963; P < .0005) and a calibration slope B of 0.984 (95% confidence interval, 0.0.726-1.243; P < .0005). The combination of the angle of progression and the head circumference can predict 87% of complicated operative vaginal deliveries and can be performed in the delivery room.

Looking back: sectio in mortua and the role of the midwife

Operative vaginal delivery and, in particular, rotational forceps delivery require extensive training, specific skills, and dexterity. Performed correctly, it can reduce the need for difficult late second-stage cesarean delivery and its associated complications. When rotation to occiput anterior position is achieved, pelvic trauma and anal sphincter injury commonly associated with direct delivery from occiput posterior positions may be avoided.We report the original and novel use of real-time intrapartum ultrasound simultaneously during Kielland’s rotational forceps delivery to monitor correct execution and increase maternal safety.This is a prospective observational study performed at the Charité University Hospital in Berlin between 2013 and 2018. Simultaneous, real-time, intrapartum suprapubic ultrasound during Kielland’s rotational forceps deliveries were performed in a series of laboring women with normal fetuses and arrest of labor in the late second stage and with a fetal head malposition, requiring operative vaginal delivery. In addition to vaginal palpation for head station, rotation, and asynclitism, intrapartum ultrasound was also used to objectively determine head station, head direction, and midline angle. The operator was not blinded to the ultrasound findings.The delivering obstetrician examined the woman and performed the delivery. An assistant, trained in intrapartum ultrasound, placed a curved-array transducer transversely in the midline just above the pubic bone to display the forceps blades being applied and the rotation of the fetal head in occiput anterior position.In all 32 laboring women included in the study, the blades were applied correctly and the fetal heads successfully rotated to an occiput anterior position with direct ultrasound confirmation, and vaginal delivery was achieved. There were no cases of difficult application, repeat application, slippage of the blades, or rotation of the fetal head in the wrong direction. Maternal outcomes showed no vaginal tears, cervical tears, or postpartum hemorrhage >500 mL. There was 1 case of third-degree perineal tear (3a). Neonatal outcomes included mild hyperbilirubinemia (n=1), small cephalohematoma conservatively managed (n=1), and early-onset group B streptococcus sepsis secondary to maternal colonization (n=1). There were no neonatal deaths.Ultrasound guidance during Kielland’s rotational forceps delivery is an original and novel approach. We describe the use of intrapartum ultrasound in assessing fetal head station and position and also to simultaneously and objectively monitor performance of rotational forceps delivery. Intrapartum ultrasound enhances operator confidence and, possibly, patient safety. It is a valuable adjunct to obstetrical training and can improve learning efficiency. Real-time ultrasound guidance of fetal head rotation to occiput anterior position with Kielland’s forceps may also protect the perineum and reduce anal sphincter injury. This novel approach can lead to a renaissance in the safe use of Kielland’s forceps.

Can we predict levator ani muscle avulsion in instrumental deliveries through intrapartum transperineal ultrasound?

Introduction: To determine whether intrapartum translabial ultrasound (ITU) is useful for the prediction of levator ani muscle (LAM) avulsions in instrumental deliveries (vacuum and forceps).Materials and methods: Prospective, observational study, including (1/2016 − 5/2016) 77 nulliparous women, with singleton pregnancies of ≥37 weeks of gestation and with cephalic presentation, who required vacuum or forceps instrumentation to complete the delivery. The ITU parameters evaluated were Angle of Progression (AoP), Progression Distance (PD), Head Direction (HD), and Midline Angle (MLA), both at rest and with maternal push. Evaluation of LAM avulsion was performed at 6 months postpartum with 3–4D transperineal ultrasound. Complete avulsion was defined as an abnormal insertion of LAM in the lower pubic branch identified in all three central slices.Results: Data from 48 nulliparous women were finally included in the study (34 vacuum and 14 forceps). We observed no difference in obstetric parameters between the two study groups (group with avulsion of LAM −14 cases, 29.2% − and group without avulsion of LAM −34 cases, 70.8%). The “LAM avulsion group” had an AoP and a PD of 136.7 ± 22.4 and 43.5 ± 15.6, respectively, versus 141.6 ± 21.3 and 47.2 ± 16.8 recorded in the group without avulsion (NS), respectively. We obtained a ROC curve for AoP and PD with a push of 0.66 (95% CI, 0.28–1.00) and 0.57 (95% CI, 0.39–0.75), respectively.Conclusions: ITU is not a useful technique to predict the occurrence of LAM avulsion in instrumental deliveries with vacuum or forceps.

Ultrasonographic evaluation of the second stage of labor. Predictive parameters for a successful vaginal delivery with or without neuraxial analgesia: a pilot study.

The aim of the study was to evaluate the progression and rotation of the fetal head during the second stage of labor using translabial ultrasound and to compare ultrasonographic data obtained in nulliparous women both receiving and not receiving neuraxial analgesia. The 49 patients enrolled in the study were divided into two groups according to receiving or not receiving neuraxial analgesia. Every half hour from full dilation to delivery, the ultrasonographic translabial parameters of Angle of Progression, Head Symphysis Distance, and Midline Angle were obtained and recorded by a single operator. Then, these records were compared between the two groups of patients. Patients that underwent neuraxial analgesia presented with increased duration of the second stage of labor, with mean values of Angle of Progression significantly higher and of Midline Angle significantly lower for each time interval studied compared to patients without analgesia. A borderline significant relationship was found between administration of neuraxial analgesia and Head Symphysis Distance. In this study, we demonstrated that combined spinal-epidural analgesia influences the duration of the second stage of labor and the initial progression and rotation of the fetal head through the birth canal, but not the kind of delivery. A correlation between Angle of Progression values and success in the application of a vacuum has been reported by other authors and confirmed in our study.

Intra and interobserver variability of intrapartum transperineal ultrasound measurements with contraction and pushing

The aim of this study was to evaluate the inter- and intraobserver correlation of the different intrapartum-transperineal-ultrasound-parameters(ITU) (angle of progression (AoP), progression-distance (PD), head-direction (HD), midline-angle (MLA) and head-perineum distance (HPD)) with contraction and pushing. We evaluated 28 nulliparous women at full dilatation under epidural analgesia. We performed a transperineal ultrasound evaluating AoP and PD in the longitudinal plane, and MLA and HPD in the transverse plane. Interclass correlation coefficients (ICC) with 95% CIs and Bland–Altman analysis were used to assess intra- and interobserver measurement’s repeatability. The ICC of the ITU for the same observer was adequate for all the parameters (p < .005) AoP 0.98 (95%CI, 0.96–0.99), PD 0.98 (95%CI, 0.97–0.99), MLA 0.99 (95%CI, 0.97–0.99), HPD 0.96 (95%CI, 0.88–0.99). The ICC of the ITU for interobserver was: AoP 0.93 (95%CI, 0.79–0.98), PD 0.92 (95%CI, 0.76–0.97), MLA 0.77 (95%CI, 0.42–0.92), HPD 0.47 (95%CI, −0.12–0.8). The HD had an interobserver correlation of 0.53 (95%CI, 0.1–0.9) (Kappa C). The mean difference of the AoP was 2.42°, of the PD 1 mm and 0.28° MLA (Bland–Altman test). ITU has an adequate intra- and interobserver correlation for its use with contraction and pushing under epidural analgesia.Impact statementWhat is already known on this subject: The intrapartum transperineal ultrasound parameters can be used with contraction and pushing under epidural analgesia.What the results of this study add to what we know: ITU may be used to evaluate the difficulty of instrumental delivery/to evaluate the difficulty of instrumentation in vaginal operative deliveries and this study concludes that ITU is reproducible during uterine contraction with pushing.What the implications are of these findings for clinical practice and/or further research: Therefore, ITU could be used without difficulty with an adequate intra- and interobserver correlation for the prediction of instrumentation difficulty in operative vaginal deliveries.

P04.09: Intrapartum ultrasound and mode of delivery in prolonged second stage of labour

To evaluate the relationship between intrapartum sonographic findings and mode of delivery in women with prolonged second stage of labour. Prospective evaluation of labouring women with prolonged second stage of labour, which was defined by pushing efforts lasting over 60 minutes regardless of epidural or parity. Eligible cases were submitted to transabdominal ultrasound (US) for the evaluation of the fetal head position and to transperineal US for the measurement of the midline angle (MLA), the head-perineum distance, the head-symphisis distance (HSD) and the angle of progression (AoP) at rest and at the acme of the pushing effort. Labour outcomes were compared in women who had spontaneous vaginal delivery (SVD) vs those who underwent obstetric intervention (OI), which included vacuum delivery and Caesarean section. Cases where OI was performed solely based on suspected fetal distress were excluded. Overall, 56 women were included. Among these, 19 (33.9%) had SVD and 37 (66.1%) underwent OI. The following differences were noted in the SVD compared with the OI group: lower median head station (1 (0 - +3) vs 1 (-2 - +3), p 0.011), higher rate of occiput anterior position (89.4% vs 57.8%, p 0.013), narrower midline angle (MLA) (24.78 ± 8.39 vs 55.32 ± 24.84, p <0.001), shorter head-symphisis distance (HSD) (15.11 ± 4.78 vs 18.99 ± 6.67, p 0.028) and wider delta-angle of progression (difference between the AoP at rest and the acme of the pushing effort) (24.28 + 11.92 vs 16.34 + 8.50, p 0.036). At multivariable regression analysis MLA was the only independent predictor of the mode of delivery (p 0.009). Below a MLA of 34.6 degrees the residual chance of OI was 41.7%. In women with prolonged second stage of labour a narrow MLA at ultrasound is the strongest predictor of SVD.

Prediction of time to delivery by transperineal ultrasound in second stage of labor.

To investigate whether the transperineal sonographic (TPS) parameters angle of progression (AoP) and midline angle (MLA) can predict the time remaining in the second stage of labor. We evaluated prospectively women with a singleton pregnancy in cephalic presentation at term between October 2013 and September 2014. TPS volumes were obtained immediately after confirmation by digital vaginal examination of a fully dilated cervix. AoP and MLA were measured offline by analyzing the ultrasound volumes. Progression of labor was evaluated every hour during the second stage. The associations of AoP and MLA with the interval between TPS assessment and delivery were evaluated using multivariable Cox proportional hazards analyses in nulliparous and parous women separately. A total of 557 women were evaluated. An AoP ≥ 160° (adjusted hazard ratio (aHR), 2.52 (95% CI, 1.98-3.19)) and MLA ≤ 10° (aHR, 1.79 (95% CI, 1.35-2.34)) in nulliparous women and an AoP ≥ 150° (aHR, 1.86 (95% CI, 1.34-2.57)) and MLA ≤ 20° (aHR, 1.69 (95% CI, 1.21-2.34)) in parous women were significantly associated with the remaining time in labor. The positive/negative likelihood ratios of AoP, MLA, clinical station (fetal head descent as observed by digital examination) and clinical rotation (fetal head rotation as observed by digital examination) at these cut-off points were 3.6/0.6, 2.0/0.6, 1.6/0.6 and 1.6/0.8, respectively, in nulliparous women, and 2.4/0.6, 1.3/0.7, 7.6/0.5 and 5.2/0.7, respectively, in parous women. TPS assessment of AoP and MLA in the second stage of labor was useful for predicting the time remaining in labor and had higher predictive value than did digital vaginal examination in nulliparous women. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Intrapartum translabial ultrasound with pushing used to predict the difficulty in vacuum-assisted delivery of fetuses in non-occiput posterior position

Objective: Our aim is to evaluate the capacity of intrapartum translabial ultrasound (ITU) with pushing in the prediction of difficulty of fetal extraction in vacuum assisted deliveries. Prospective, observational study performed (2/2015–8/2015) on 75 nulliparous women, ≥37 weeks with singleton pregnancies at full dilatation who had ITU-with-pushing performed, previous to vacuum-placement for fetal extraction. Working on the translabial sagittal-plane, we assessed: Angle-Progression (AoP), Progression-Distance (PD) and Head-Direction (HD); in the axial plane we evaluated: Midline-Angle (MLA) and Head-Perineum-Distance (HPD). Vacuum extractions were classified as easy-difficulty (ED) (≤3 vacuum-pulls), difficult-unsuccessful (DD) (>3 vacuum-pulls). We did not assess occipito-posterior-presentations.Results: Seventy nulliparous were studied (44-ED,26-DD). We observed no differences in obstetric, neonatal or intrapartum characteristics between the two study groups, with the following exceptions: newborn weight (3272 ± 438 g versus 3540 ± 372 g; p = 0.011) and number of vacuum-pulls (1.4-ED-vs-4.4-DD; p < 0.0005). AoP-pushing was 143.9° ± 14.6° in ED and 115.1°± 12.9° in DD (p < 0.0005); Head-Up was 79.5% versus 38.4% (p < 0.0005); PD-Pushing was 42.7 ± 11.3 mm versus 30.4 ± 9.8 mm (p < 0.0005); MLA-Pushing was 27.6°± 26.6° versus 57.5°±26.5°(p=0.025); HPD-Pushing was 40.8 ± 10.0 mm versus 47.4 ± 10.9 mm (p = 0.039).Conclusion: We identified that the presence of an AoP-Pushing > 128° predicts an Easy-Vacuum-Delivery (≤3 Vacuum-Pulls) in >85% of cases (Sen 80%–FPR 9.3%).

Utility of intrapartum transperineal ultrasound to predict cases of failure in vacuum extraction attempt and need of cesarean section to complete delivery

Objectives: We aim to evaluate the predictive capacity of intrapartum transperineal ultrasound (ITU) to predict cases of failure in fetal extraction in operative deliveries with vacuum. Prospective, observational study performed on 61 nulliparous women, ≥37 weeks, singleton pregnancies at full dilatation who underwent transperineal ultrasound before placement of vacuum to complete fetal extraction. Working on the transperineal longitudinal plane, we evaluated the following: Angle of Progression (AoP), Progression Distance (PD) and head direction. In the transverse plane, midline angle (MLA) and head–perineum distance were assessed. Vacuum extractions were classified as easy (EG) (three or less vacuum pulls), difficult (DG) (more than three vacuum pulls) or impossible (IG) (delivery completed by cesarean section). Occipito-posterior presentations were not evaluated.Results: Fifty-two patients were studied (26-EG, 19-DG and 7-IG). No differences in obstetric, intrapartum or neonatal characteristics were observed between study groups, with the following exceptions: weight at birth (3147 g-EG, 3523 g-DG and 3588 g-IG) and number of vacuum pulls (1.4-EG, 4.4-DG and 4.1-IG; p < 0.0005). The AoP pushing was 133.1° ± 13.6-EG, 112.8° ± 12.8-DG and 99.1° ± 8.9-IG (p < 0.0005); “head-up” direction was identified in 84.6% of EG, 36.8% of DG and 28.6% of IG (p < 0.001); PD were 37.0 ± 10.4 mm, 33.3 ± 23.3 mm and 20.8 ± 9.5 mm (p < 0.0005); MLA were 35.0° ± 19.6, 55.3° ± 24.4 and 76.0° ± 23.2 (p = 0.003); and head–perineum distances were 41.8 ± 6.6 mm, 49.2 ± 9.8 mm and 48.0 ± 3.4 mm (p = 0.072), respectively.Conclusion: We have observed that the presence of an AoP with pushing <105°, a PD <25 mm, a “head-down” direction and a >45° MLA are very unfavorable ITU parameters which can be used to identify cases of high risk of fetal extraction failure in vacuum-assisted deliveries.

Morphometric Analysis of Lumbar Pedicles in Patients with Spinal Dysraphism

Background: In patients with open neural tube defects, the incidence of scoliosis and requirement for spinal fusions are increased. Historically, there has been no standardized measurement of vertebral morphometry in these patients. However, anecdotally, patients with open neural tube defects have a more medially oriented lumbar pedicle trajectory than the average population. Methods: A single-institution retrospective review of patients with open neural tube defects was conducted. The demographic parameters and functional and anatomical levels of the defects were noted. CT and MRI scans of the lumbar spine were analyzed; the pedicles from L₁ to S₁ were measured for width (W), length (L) and midline angle (α). The measurements were compared bilaterally, at each level, and with data from previously published reports. Results: 16 scans of pediatric patients (mean = 3.0 ± 4.3; age range = 7 days to 14.4 years; 7 males, 9 females) with a diagnosis of either myelomeningocele or lipomyelomeningocele were assessed. Most defects occurred in the lumbar region, with L₂ and L₅ accounting for 37.5% each. All angles demonstrated a quadratic increase from L₁ to S₁ (means: L₁ = 28.3 ± 5.24°; L₂ = 29.1 ± 6.2°; L₃ = 33.2 ± 6.0°; L₄ = 36.8 ± 5.6°; L₅ = 43.8 ± 5.9°; S₁ = 52.0 ± 3.6°) and were more medially angulated than those reported previously; no significant difference existed between right and left measurements (W = 0.65 ≤ p ≤ 0.94; L = 0.91 ≤ p ≤ 1; α = 0.24 ≤ p ≤ 0.86). Conclusions: Patients with open neural tube defects had more medially angled pedicle trajectories in the lumbar spine when compared to previously reported values.