Assessing Postpartum Levator Ani Muscle Recovery: A Feasibility Study on Automated Texture Analysis in Transvaginal Ultrasound.

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

PurposeThe risk of pelvic floor muscle injury is commonly considered to be higher in vaginal than in cesarean delivery. This study aimed to compare levator ani muscle (LAM) elasticity after vaginal and cesarean delivery using shear wave elastography (SWE).MethodsPostpartum women who underwent a single SWE evaluation 1 month after their first delivery were divided into vaginal and cesarean delivery groups. The elastic moduli of both sides of the LAM were measured in a horizontal section and compared between the groups. In addition, a subgroup analysis was performed to compare LAM elasticity according to the delivery method within the vaginal delivery group—normal vaginal delivery, episiotomy, and operative vaginal delivery.ResultsSixty-two women were included (vaginal delivery, n = 47; elective cesarean section, n = 15). Multiple regression analysis revealed that the LAM elastic modulus was significantly lower in the vaginal delivery group than in the cesarean delivery group (right LAM: 44.2 vs. 72.7 kPa, p = 0.0036; left LAM 40.4 vs. 82.7 kPa, p < 0.0001). In the subgroup analysis, the right LAM elastic modulus was significantly lower in the operative vaginal delivery subgroup than in the normal vaginal delivery subgroup (p = 0.0131). However, there was no significant difference in the left LAM elastic modulus between the three subgroups.ConclusionLAM elasticity was significantly lower after vaginal delivery than after cesarean delivery. Furthermore, the elasticity of the right LAM was lower after operative vaginal delivery than after normal vaginal delivery. SWE has the potential to provide an objective quantitative assessment of postpartum pelvic floor muscle recovery.

INTRODUCTION: This study compared the relative odds of levator ani muscle injury using three-dimensional ultrasonography after forceps compared with vacuum delivery. METHODS: This was a retrospective cohort study. Women who had undergone at least one forceps delivery were compared with women who had undergone at least one vacuum birth. Participants were 5–10 years from first delivery. Three-dimensional transperineal ultrasound volumes were captured as cine loops at rest, with Valsalva and with squeeze. The primary outcome was levator ani muscle avulsion. Secondary outcomes included levator–urethral gap, hiatal diameter, and area. RESULTS: Among 89 participants, there were no differences in maternal age at first delivery, parity, body mass index, birth weight, episiotomy, any perineal laceration, or duration of the second stage of labor among women in the two vaginal delivery groups. However, anal sphincter lacerations were more common in the forceps vaginal delivery group. The odd of levator ani muscle avulsion was four times higher for women in forceps vaginal delivery group compared to vacuum vaginal delivery group (odds ratio 4.15, 95% confidence interval 1.32–14.42). Women in the forceps vaginal delivery group also had wider levator–urethral gap, larger hiatal diameter, and widened hiatal area at Valsalva and squeeze. Among women who had forceps vaginal delivery, levator avulsions were associated with older age and lower parity. CONCLUSIONS: Levator avulsion is more common among women with a history of forceps vaginal delivery than vacuum-assisted vaginal delivery. This difference may contribute to the increased prevalence of pelvic floor disorders after forceps compared with vacuum delivery.

The study aimed to explore the value of ultrasound (US) texture analysis in the differential diagnosis of triple-negative breast cancer (TNBC) and non-TNBC.Retrospective analysis was done on 93 patients with breast cancer (35 patients with TNBC and 38 patients with non-TNBC) who were admitted to Taizhou people's hospital from July 2015 to June 2019. All lesions were pathologically proven at surgery. US images of all patients were collected. Texture analysis of US images was performed using MaZda software package. The differences between textural features in TNBC and non-TNBC were assessed. Receiver operating characteristic curve analysis was used to compare the diagnostic performance of textural parameters showing significant difference.Five optimal texture feature parameters were extracted from gray level run-length matrix, including gray level non-uniformity (GLNU) in horizontal direction, vertical gray level non-uniformity, GLNU in the 45 degree direction, run length non-uniformity in 135 degree direction, GLNU in the 135 degree direction. All these texture parameters were statistically higher in TNBC than in non-TNBC (P <.05). Receiver operating characteristic curve analysis indicated that at a threshold of 268.9068, GLNU in horizontal direction exhibited best diagnostic performance for differentiating TNBC from non-TNBC. Logistic regression model established based on all these parameters showed a sensitivity of 69.3%, specificity of 91.4% and area under the curve of 0.834.US texture features were significantly different between TNBC and non-TNBC, US texture analysis can be used for preliminary differentiation of TNBC from non-TNBC.

Description and assessment by 3-D transperineal ultrasound of modifications suffered by pelvic floor muscles during the passage of the fetal head through the birth canal during the second stage of labor, as well as the identification of the precise moment in which levator ani muscle avulsion takes place. Patients included were 35 primigravidae, recruited during the first stage of labor, with at term pregnancy (37-42 weeks), without serious maternal-fetal pathology and cephalic presentation. A prospective observational study of 35 primigravidae, recruited during the first stage of labor, with at term pregnancy (37-42 weeks), with fetus in cephalic presentation and without serious maternal-fetal pathology. Sonographic evaluation was carried out by 3-D transperineal ultrasound during the first and second stages of labor (with fetal head in 1st, 2nd-3rd and 4th planes of Hodge), immediately postpartum and 6 months postpartum. Ultrasound parameters studied were antero-posterior and transverse diameters, as well as levator hiatus area and levator ani muscle thickness and area. Twenty-one patients were studied (15 spontaneous deliveries; 6 instrumental deliveries). When measured with fetal head in the 4th plane of Hodge, a significant increase both in the levator hiatus area (15.39 cm2 /15.68 cm2 /20.96 cm2 /42.55 cm2 /22.92 cm2 /18.18 cm2 ; P < 0.0005) and in the levator ani muscle area (8.78 cm2 /9.18 cm2 /9.69 cm2 /15.07 cm2 /11.33 cm2 /12.36 cm2 ; P < 0.0005) was identified. Four cases of unilateral right avulsion (two vacuum and two forceps deliveries) were identified. We conclude that the phase of delivery that causes a major increase in the area of the levator hiatus area and in the levator ani muscle area is when the fetal head reaches the 4th plane of Hodge. Furthermore, data in our paper indicates that the exact moment in which the avulsion of the levator ani muscle is produced is when the bulging of the fetal head on the maternal perineum occurs.

Pelvic floor dysfunction (PFD) due to vaginal delivery is related to tear of levator ani muscle (LAM) that potentially lead to the impairment of quality of life among women. A number of attempts to predict LAM injury after vaginal delivery had been conducted. This study aims to appraise the accuracy of several prediction index determining LAM injury after vaginal delivery. We conducted a search in Cochrane Library®, Pubmed®, and Medline® with the keywords of “pelvic floor dysfunction” AND “vaginal delivery” AND “prediction.” Critical appraisal determining the validity, importance, and applicability (VIA) was conducted by 2 independent authors. After 6 weeks to 3 months’ duration of follow up, the incidence of LAM avulsion was varied from 15.4% to 35.6% from three studies. Multivariate analysis showed that forceps delivery, OASIS, and active second stage (OR 3.8; 3.1; 1.61; respectively) as the most influential factors for LAM incidence. Maternal age and time spent in active pushing were also contributed to LAM incidence. OASIS and second stage of labor could be used as the most influential components of prediction index for LAM incidence. Prediction indexes for LAM incidence are developed. OASIS and second stage of labor are acknowledged as two most influential variables among three appraised studies.

Angle of progression (AoP) is an accurate and reproducible parameter for assessment of fetal descent. The aim of this study was to evaluate the usefulness of the AoP in the management of prolonged second stage of labour by analysing the change of AoP during second stage in the vaginal delivery group compared to the failed vaginal delivery group. This study included nulliparous women who had term delivery in cephalic presentation in Korea University Guro Hospital and took intrapartum ultrasonogram to measure AoP since cervix was fully dilated. We compared change of AoP during 2nd stage of the labour between the vaginal delivery group and the failed vaginal delivery group. No significant differences were found between two groups in maternal age, gestational age, birth weight, use of epidural anesthesia and oxytocin. Duration between 6cm cervical dilatation and full dilatation was longer in the failed vaginal delivery group compared to vaginal delivery group. AoP were measured in 176 women (147 vaginal deliveries, 29 emergency Caesarean section) since cervix was fully dilated. We analysed AoP data measured for the last time before delivery. Median AoP was significantly higher in the vaginal delivery group compared to the failed vaginal delivery group (136.16±19.12° vs 118.97±16.11° ; P < 0.01). For the prediction of successful vaginal delivery, the optimal AoP cut-off was 125°. AoP was significantly higher in vaginal delivery group compared to the failed vaginal delivery group when second stage of labour lasted more than 120 minutes (139.79±16.09° vs 119.78±16.82°; P < 0.01). Labour dystocia is the most common indication for primary Caesarean section. To reduce the rate of primary Caesarean section, accurate measurement of fetal station is very crucial during the second stage of labour. AoP seems to be very useful in the management of prolonged second stage of labour. AoP may serve as a guidance to clinicians whether vaginal delivery can be expected or not.

Pelvic floor dysfunction and pelvic organ prolapse have been associated with damage to the levator ani (LA) muscle, but the exact mechanisms linking them remain unknown. It has been postulated that factors such as vaginal birth and ageing may contribute to long-term, irreversible LA muscle damage. To investigate the biomechanical significance of the LA muscle during childbirth, researchers and clinicians have used finite element models to simulate the second stage of labour. One of the challenges is to represent the anisotropic mechanical response of the LA muscle. In this study, we investigated the effects of anisotropy by varying the relative stiffness between the fibre and the matrix components, whilst maintaining the same overall stress-strain response in the fibre direction. A foetal skull was passed through two pelvic floor models, which incorporated the LA muscle with different anisotropy ratios. Results showed a substantial decrease in the magnitude of the force required for delivery as the fibre anisotropy was increased. The anisotropy ratio markedly affected the mechanical response of the LA muscle during a simulated vaginal delivery. It is apparent that we need to obtain experimental data on muscle mechanics in order to better approximate the LA muscle mechanical properties for quantitative analysis. These models may advance our understanding of the injury mechanisms of pelvic floor during childbirth.

Background: Pelvic organ prolapse seriously affect women’s physical and mental health. To quantitatively analyze the structure of the pelvic floor during pregnancy and delivery, we utilized transperineal three-dimensional ultrasound (TP-3DUS) imaging combined with real-time shear wave elastography (RT-SWE). This analysis aims to provide exploratory data on female pelvic floor parameters, such as the hardness and thickness of the levator ani muscle (LAM), and to offer personalized recommendations for the prevention and treatment of early clinical pelvic organ prolapse (POP). Methods: From March 2021 to August 2022, a study was conducted at the Affiliated Hospital of Yunnan University involving 150 pregnant patients at various gestational ages, 110 primiparas at 42–45 days post-delivery, and 55 healthy non-childbearing women. RT-SWE was used to quantitatively evaluate changes in the elasticity of the puborectalis muscle (PRM), while TP-3DUS imaging was used to measure various parameters of the pelvic floor. This study investigated changes in pelvic floor structure during pregnancy and postpartum. It evaluated the efficacy of PRM elasticity, levator hiatus (LH) area (LHA), and the thickness of the LAM, along with their combined application in diagnosing early postpartum POP. Results: As gestational weeks progress, the elasticity of PRM increased, while the thickness of LAM decreased. In the control group, cesarean section group, and vaginal delivery group, the elasticity of the PRM and the thickness of the LAM progressively decreased. The area, perimeter, LH anteroposterior (LHAP) diameter and LH lateral diameter (LHLD) increased sequentially in these groups. The combination of LHA, PRM elasticity, and thickness of the LAM in both vaginal delivery and cesarean section groups demonstrated the highest diagnostic efficiency for POP. Conclusions: The combination of TP-3DUS Imaging and RT-SWE represents a novel, effective, and convenient method for evaluating the structure and muscle elasticity of the pelvic floor during pregnancy and the early postpartum period. LHA, PRM hardness, and thickness of the LAM individually possess a diagnostic value for early postpartum POP. However, their combination yields the highest diagnostic efficiency.

To assess the impact of different modes of delivery, vaginal delivery, and cesarean section, on the levator ani muscle (LAM) and pelvic organ prolapse (POP) in women with twin pregnancies using pelvic floor ultrasound. 84 pregnant women with twin pregnancies were randomized either into the vaginal delivery group or the cesarean section group. The incidence of LAM injury was significantly lower in the cesarean section. The resting state and maximum Valsalva maneuver state LAM cleft areas were smaller in the cesarean section group, while the difference (Δ) in LAM area was larger. The sensitivity of LAM injury in diagnosing POP was 0.667. The optimal cutoff value for diagnosing POP based on the resting state LAM cleft area was determined to be 15.37. Pelvic floor ultrasound assessment of LAM status demonstrated some predictive value for the occurrence of POP at 6 months postpartum.

To identify the anatomical morphology of levator ani (LA) in primigravidae at term pregnancy and its natural process of changing after delivery. Forty-one primigravidae (vaginal delivery: 29 women, cesarean delivery in the first stage of labor: 12 women) underwent magnetic resonance imaging (MRI) at full-term pregnancy, 6 weeks and 10months postpartum. Three-dimensional (3-D) model of LA created from MRI data using Mimics v.21.0 software and source images were assessed to determine the morphology. LA volume (LVOL) was calculated and used as indicator of muscle atrophy. Decrease of levator hiatus length (LH-L) was shown in both groups since 6 weeks postpartum. In the vaginal delivery group, the differences in LVOL between time points were significant (p < 0.05), showing a persistent decreasing tendency. Puborectalis attachment width (PAW) on the left was the smallest at 6 weeks postpartum (p < 0.05). LA avulsion and significant 2-D morphological change after delivery were only observed in this group (p < 0.05); In the cesarean section group, smaller LVOL was found at 6 weeks postpartum comparing with full-term pregnancy (p < 0.05); Larger levator-symphysis gap (LSG) and levator hiatus width (LH-W), smaller PAW were observed in vaginal delivery group comparing with cesarean section group at 6 weeks postpartum (p < 0.05), but none of the values exhibited between-group differences (p > 0.05) at 10months postpartum. No other comparisons were considered significant (p >0.05). Vaginal delivery, or even active labor itself may both lead to LA atrophy. And the morphology of LA is basically similar in different delivery modes at 10months postpartum once the onset of labor has occurred, even though it changes more complicatedly after vaginal delivery.

To assess the evolution of levator ani muscle (LAM) avulsion from 1 year to 8 years after first delivery in women with and those without subsequent vaginal delivery. In addition, to assess whether women with full or partial avulsion 8 years after first delivery have larger LAM hiatal area and more symptoms of pelvic organ prolapse compared to women with normal LAM insertion. In this single-center longitudinal study, 195 women who were primiparous at the start of the study were included and underwent transperineal ultrasound examination 1 year and 8 years after first delivery. Muscle insertion was assessed by tomographic ultrasound imaging in the axial plane. Full LAM avulsion was defined as abnormal muscle insertion in all three central slices. Partial LAM avulsion was defined as abnormal muscle insertion in one or two central slices. Eight years after the first delivery, LAM hiatal area was assessed at rest, during maximum pelvic floor muscle contraction and on maximum Valsalva maneuver. To assess symptoms of pelvic organ prolapse, the vaginal symptoms module of the International Consultation on Incontinence Questionnaire was used. At 1-year follow-up, 25 (12.8%) women showed signs of LAM avulsion, of whom 20 fulfilled the sonographic criteria of full avulsion and five of partial avulsion. Eight years after the first delivery, 35 (17.9%) women were diagnosed with avulsion, of whom 25 were diagnosed with full avulsion and 10 with partial avulsion. No woman with partial or full avulsion at 1 year had improved avulsion status at 8-year follow-up. Of the 150 women who had subsequent vaginal delivery, 21 (14.0%) women were diagnosed with partial or full LAM avulsion 1 year after first delivery, and 31 (20.7%) women were diagnosed with partial or full avulsion 8 years after first delivery. Of the 45 women without subsequent vaginal delivery, one woman with partial avulsion 1 year after first delivery was diagnosed with full avulsion at 8-year follow-up. All women with full avulsion at 1-year follow-up were diagnosed with full avulsion at 8-year follow-up regardless of whether they had subsequent vaginal delivery. At 8-year follow-up, women with full avulsion had statistically significantly larger LAM hiatal area compared to women with normal muscle insertion. Mean ± SD vaginal symptom scores ranged between 5.5 ± 5.7 and 6.0 ± 4.0 and vaginal symptom quality of life scores ranged between 0.9 ± 1.4 and 1.5 ± 2.2 and did not differ significantly between women with normal muscle insertion and women with partial or full avulsion at 8-year follow-up. More LAM avulsions were present 8 years compared with 1 year after first delivery in women with subsequent vaginal delivery. Except for one primipara, all women without subsequent vaginal delivery had unchanged LAM avulsion status between 1 year and 8 years after their first delivery. Larger LAM hiatal area was found in women with full avulsion compared to those with normal muscle insertion at 8-year follow-up. Vaginal symptoms scores were low and did not differ between women with normal muscle insertion and those with partial or full avulsion at 8-year follow-up. © 2024 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

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.

To compare levator defect, loss of tenting, change in biometric measurements of the levator ani and genital hiatus according to the mode of delivery, length of the labor, Bishop score, birthweight and head circumference immediately after delivery. One hundred and seventy-one primiparous women who delivered either by vaginal delivery or cesarean were prospectively evaluated. Two 3-D volumes (one at rest, one on Valsalva maneuver) were recorded in the supine position after voiding, and levator biometry, levator defect and loss of tenting were determined on the axial plane. Of 171 nulliparous women, 84 had vaginal delivery and 87 had cesarean delivery. All hiatal dimensions on resting and maximal Valsalva were found to be higher in the vaginal delivery group. Levator defect rate was found to be significantly higher in the vaginal delivery group (P<0.0001). We found a positive correlation with head circumference, fetal weight and first stage labor length in women who delivered vaginally. In the cesarean delivery group, mean fetal head circumference, fetal weight, length of first stage of labor and Bishop score were higher in women with levator ani defect. Loss of tenting rate was significantly higher in vaginal delivery women (P=0.03). Labor itself, and factors such as fetal head circumference and fetal weight that cause prolongation of labor, can induce levator ani muscle defect or microtrauma which in turn can cause morphological alterations of the levator hiatus.

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