Pelvic floor injury during vaginal birth is life-altering and preventable: what can we do about it?

Pelvic floor disorders after childbirth have distressing lifelong consequences for women, requiring more than 300,000 women to have surgery annually. This represents approximately 10% of the 3 million women who give birth vaginally each year. Vaginal birth is the largest modifiable risk factor for prolapse, the pelvic floor disorder most strongly associated with birth, and is an important contributor to stress incontinence. These disorders require 10 times as many operations as anal sphincter injuries. Imaging shows that injuries of the levator ani muscle, perineal body, and membrane occur in up to 19% of primiparous women. During birth, the levator muscle and birth canal tissues must stretch to more than 3 times their original length; it is this overstretching that is responsible for the muscle tear visible on imaging rather than compression or neuropathy. The injury is present in 55% of women with prolapse later in life, with an odds ratio of 7.3, compared with women with normal support. In addition, levator damage can affect other aspects of hiatal closure, such as the perineal body and membrane. These injuries are associated with an enlarged urogenital hiatus, now known as antedate prolapse, and with prolapse surgery failure. Risk factors for levator injury are multifactorial and include forceps delivery, occiput posterior birth, older maternal age, long second stage of labor, and birthweight of >4000 g. Delivery with a vacuum device is associated with reduced levator damage. Other steps that might logically reduce injuries include manual rotation from occiput posterior to occiput anterior, slow gradual delivery, perineal massage or compresses, and early induction of labor, but these require study to document protection. In addition, teaching women to avoid pushing against a contracted levator muscle would likely decrease injury risk by decreasing tension on the vulnerable muscle origin. Providing care for women who have experienced difficult deliveries can be enhanced with early recognition, physical therapy, and attention to recovery. It is only right that women be made aware of these risks during pregnancy. Educating women on the long-term pelvic floor sequelae of childbirth should be performed antenatally so that they can be empowered to make informed decisions about management decisions during labor.

Electrodiagnostic subtyping in Guillain-Barré syndrome patients in the International Guillain-Barré Outcome Study.

BACKGROUND AND PURPOSE: Various electrodiagnostic criteria have been developed in Guillain-Barré syndrome (GBS). Their performance in a broad representation of GBS patients has not been evaluated. Motor conduction data from the International GBS Outcome Study (IGOS) cohort were used to compare two widely used criterion sets and relate these to diagnostic amyotrophic lateral sclerosis criteria. METHODS: From the first 1500 patients in IGOS, nerve conduction studies from 1137 (75.8%) were available for the current study. These patients were classified according to nerve conduction studies criteria proposed by Hadden and Rajabally. RESULTS: Of the 1137 studies, 68.3% (N = 777) were classified identically according to criteria by Hadden and Rajabally: 111 (9.8%) axonal, 366 (32.2%) demyelinating, 195 (17.2%) equivocal, 35 (3.1%) inexcitable and 70 (6.2%) normal. Thus, 360 studies (31.7%) were classified differently. The areas of differences were as follows: 155 studies (13.6%) classified as demyelinating by Hadden and axonal by Rajabally; 122 studies (10.7%) classified as demyelinating by Hadden and equivocal by Rajabally; and 75 studies (6.6%) classified as equivocal by Hadden and axonal by Rajabally. Due to more strictly defined cutoffs fewer patients fulfilled demyelinating criteria by Rajabally than by Hadden, making more patients eligible for axonal or equivocal classification by Rajabally. In 234 (68.6%) axonal studies by Rajabally the revised El Escorial (amyotrophic lateral sclerosis) criteria were fulfilled; in axonal cases by Hadden this was 1.8%. CONCLUSIONS AND DISCUSSION: This study shows that electrodiagnosis in GBS is dependent on the criterion set utilized, both of which are based on expert opinion. Reappraisal of electrodiagnostic subtyping in GBS is warranted.

Functional Anatomy of Urogenital Hiatus Closure: the Perineal Complex Triad Hypothesis.

INTRODUCTION: Urogenital hiatus enlargement is a critical factor associated with prolapse and operative failure. This study of the perineal complex was performed to understand how interactions among its three structures: the levator ani, perineal membrane, and perineal body-united by the vaginal fascia-work to maintain urogenital hiatus closure. METHODS: Magnetic resonance images from 30 healthy nulliparous women with 3D reconstruction of selected subjects were used to establish overall geometry. Connection points and lines of action were based on perineal dissection in 10 female cadavers (aged 22-86 years), cross sections of 4 female cadavers (aged 14-35 years), and histological sections (cadavers aged 16 and 21 years). RESULTS: The perineal membrane originates laterally from the ventral two thirds of the ischiopubic rami and attaches medially to the perineal body and vaginal wall. The levator ani attaches to the perineal membrane's cranial surface, vaginal fascia, and the perineal body. The levator line of action in 3D reconstruction is oriented so that the levator pulls the medial perineal membrane cranio-ventrally. In cadavers, simulated levator contraction and relaxation along this vector changes the length of the membrane and the antero-posterior diameter of the urogenital hiatus. Loss of the connection of the left and right perineal membranes through the perineal body results in diastasis of the levator and a widened hiatus, as well as a downward rotation of the perineal membrane. CONCLUSION: Interconnections involving the levator ani muscles, perineal membrane, perineal body, and vaginal fascia form the perineal complex surrounding the urogenital hiatus in an arrangement that maintains hiatal closure.

Comparison of the Vaginal and Labial Dimensions of Ethnic Chinese and Western Nullipara.

INTRODUCTION AND HYPOTHESIS: Vaginal dimensions have clinical and surgical implications. We sought to quantify the differences between vaginal and labial dimensions in healthy ethnic Chinese and Western women with normal pelvic organ support. METHODS: This is a cross-sectional study of a convenience sample of ethnic Chinese nulliparas (n = 33) and Western nulliparas (n = 33) recruited for research purposes. For each subject, magnetic resonance imaging was used to quantify the vaginal and labial dimensions. Specifically, we identified the anterior and posterior vaginal wall, the outline of the cervix in the mid-sagittal and coronal planes, and the distance from the labia majora to the hymenal ring at the urethral meatus. RESULTS: There were significant differences in age and weight between groups. Substantial variation in vaginal and labial dimensions was found within each group. The vaginal and labial dimensions of ethnic Chinese women ranged from 9-21% smaller than those of Western women; In the ethnic Chinese group, increasing weight and BMI correlated with greater labial distance (r = 0.66 and r = 0.63 respectively); as did height and the distance from the vaginal opening to the cervical os (r = 0.5). In the Western group, only weight correlated with the labial distance (r = 0.51). CONCLUSIONS: Significant group differences in vaginal and labial dimensions were found, with the dimensions of Chinese nulliparas being up to 21% smaller than those of Western nulliparas.

Predicting Leg Forces and Knee Moments Using Inertial Measurement Units: An In Vitro Study.

We compared the ability of seven machine learning algorithms to use wearable inertial measurement unit (IMU) data to identify the severe knee loading cycles known to induce microdamage associated with anterior cruciate ligament rupture. Sixteen cadaveric knee specimens, dissected free of skin and muscle, were mounted in a rig simulating standardized jump landings. One IMU was located above and the other below the knee, the applied three-dimensional action and reaction loads were measured via six-axis load cells, and the three-dimensional knee kinematics were also recorded by a laboratory motion capture system. Machine learning algorithms were used to predict the knee moments and the tibial and femur vertical forces; 13 knees were utilized for training each model, while three were used for testing its accuracy (i.e., normalized root-mean-square error) and reliability (Bland-Altman limits of agreement). The results showed the models predicted force and knee moment values with acceptable levels of error and, although several models exhibited some form of bias, acceptable reliability. Further research will be needed to determine whether these types of models can be modified to attenuate the inevitable in vivo soft tissue motion artifact associated with highly dynamic activities like jump landings.

A unified pelvic floor conceptual model for studying morphological changes with prolapse, age, and parity.

Several 2-dimensional and 3-dimensional measurements have been used to assess changes in pelvic floor structures and shape. These include assessment of urogenital and levator hiatus dimensions, levator injury grade, levator bowl volume, and levator plate shape. We argue that each assessment reflects underlying changes in an individual aspect of the overall changes in muscle and fascial structures. Vaginal delivery, aging, and interindividual variations in anatomy combine to affect pelvic floor structures and their connections in different ways. To date, there is no unifying conceptual model that permits the evaluation of how these many measures relate to one another or that reflects overall pelvic floor structure and function. Therefore, this study aimed to describe a unified pelvic floor conceptual model to better understand how the aforementioned changes to the pelvic floor structures and their biomechanical interactions affect pelvic organ support with vaginal birth, prolapse, and age. In this model, the pelvic floor is composed of 5 key anatomic structures: the (1) pubovisceral, (2) puborectal, and (3) iliococcygeal muscles with their superficial and inferior fascia; (4) the perineal membrane or body; and (5) the anal sphincter complex. Schematically, these structures are considered to originate from pelvic sidewall structures and meet medially at important connection points that include the anal sphincter complex, perineal body, and anococcygeal raphe. The pubovisceral muscle contributes primarily to urogenital hiatus closure, whereas the puborectal muscle is mainly related to levator hiatus closure, although each muscle contributes to the other. Dorsally and laterally, the iliococcygeal muscle forms a shelflike structure in women with normal support that spans the remaining area between these medial muscles and attachments to the pelvic sidewall. Other features include the levator plate, bowl volume, and anorectal angle. The pelvic floor conceptual model integrates existing observations and points out evident knowledge gaps in how parturition, injury, disease, and aging can contribute to changes associated with pelvic floor function caused by the detachment of one or more important connection points or pubovisceral muscle failure.

Two emerging phenotypes of atypical inclusion body myositis: illustrative cases.

OBJECTIVES: Sporadic inclusion body myositis (IBM) is the most common acquired myopathy in those aged above 50. It is classically heralded by weakness in the long finger flexors and quadriceps. The aim of this article is to describe five atypical cases of IBM, outlining two potential emerging clinical subsets of the disease. METHODS: We reviewed relevant clinical documentation and pertinent investigations for five patients with IBM. RESULTS: The first phenotype we describe is young-onset IBM in two patients who had symptoms since their early thirties. The literature supports that IBM can rarely present in this age range or younger. We describe a second phenotype in three middle-aged women who developed early bilateral facial weakness at presentation in tandem with dysphagia and bulbar impairment followed by respiratory failure requiring non-invasive ventilation (NIV). Within this group, two patients were noted to have macroglossia, another possible rare feature of IBM. CONCLUSIONS: Despite the classical phenotype described within the literature IBM can present in a heterogenous fashion. It is important to recognise IBM in younger patients and investigate for specific associations. The described pattern of facial diplegia, severe dysphagia, bulbar dysfunction and respiratory failure in female IBM patients requires further characterisation. Patients with this clinical pattern may require more complex and supportive management. Macroglossia is a potentially under recognised feature of IBM. The presence of macroglossia in IBM warrants further study, as its presence may lead to unnecessary investigations and delay diagnosis.

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.

On the management of maternal pushing during the second stage of labor: a biomechanical study considering passive tissue fatigue damage accumulation.

BACKGROUND: During the second stage of labor, the maternal pelvic floor muscles undergo repetitive stretch loading as uterine contractions and strenuous maternal pushes combined to expel the fetus, and it is not uncommon that these muscles sustain a partial or complete rupture. It has recently been demonstrated that soft tissues, including the anterior cruciate ligament and connective tissue in sheep pelvic floor muscle, can accumulate damage under repetitive physiological (submaximal) loads. It is well known to material scientists that this damage accumulation can not only decrease tissue resistance to stretch but also result in a partial or complete structural failure. Thus, we wondered whether certain maternal pushing patterns (in terms of frequency and duration of each push) could increase the risk of excessive damage accumulation in the pelvic floor tissue, thereby inadvertently contributing to the development of pelvic floor muscle injury. OBJECTIVE: This study aimed to determine which labor management practices (spontaneous vs directed pushing) are less prone to accumulate damage in the pelvic floor muscles during the second stage of labor and find the optimum approach in terms of minimizing the risk of pelvic floor muscle injury. STUDY DESIGN: We developed a biomechanical model for the expulsive phase of the second stage of labor that includes the ability to measure the damage accumulation because of repetitive physiological submaximal loads. We performed 4 simulations of the second stage of labor, reflecting a directed pushing technique and 3 alternatives for spontaneous pushing. RESULTS: The finite element model predicted that the origin of the pubovisceral muscle accumulates the most damage and so it is the most likely place for a tear to develop. This result was independent of the pushing pattern. Performing 3 maternal pushes per contraction, with each push lasting 5 seconds, caused less damage and seemed the best approach. The directed pushing technique (3 pushes per contraction, with each push lasting 10 seconds) did not reduce the duration of the second stage of labor and caused higher damage accumulation. CONCLUSION: The frequency and duration of the maternal pushes influenced the damage accumulation in the passive tissues of the pelvic floor muscles, indicating that it can influence the prevalence of pelvic floor muscle injuries. Our results suggested that the maternal pushes should not last longer than 5 seconds and that the duration of active pushing is a better measurement than the total duration of the second stage of labor. Hopefully, this research will help to shed new light on the best practices needed to improve the experience of labor for women.

Multi-label classification of pelvic organ prolapse using stress magnetic resonance imaging with deep learning.

INTRODUCTION AND HYPOTHESIS: We aimed to develop a deep learning-based multi-label classification model to simultaneously diagnose three types of pelvic organ prolapse using stress magnetic resonance imaging (MRI). METHODS: Our dataset consisted of 213 midsagittal labeled MR images at maximum Valsalva. For each MR image, the two endpoints of the sacrococcygeal inferior-pubic point line were auto-localized. Based on this line, a region of interest was automatically selected as input to a modified deep learning model, ResNet-50, for diagnosis. An unlabeled MRI dataset, a public dataset, and a synthetic dataset were used along with the labeled image dataset to train the model through a novel training strategy. We conducted a fivefold cross-validation and evaluated the classification results using precision, recall, F1 score, and area under the curve (AUC). RESULTS: The average precision, recall, F1 score, and AUC of our proposed multi-label classification model for the three types of prolapse were 0.84, 0.72, 0.77, and 0.91 respectively, which were improved from 0.64, 0.53, 0.57, and 0.83 from the original ResNet-50. Classification took 0.18 s to diagnose one patient. CONCLUSIONS: The proposed deep learning-based model were demonstrated feasible and fast in simultaneously diagnosing three types of prolapse based on pelvic floor stress MRI, which could facilitate computer-aided prolapse diagnosis and treatment planning.

Pelvic floor muscle injury during a difficult labor. Can tissue fatigue damage play a role?

Pubovisceral muscle (PVM) injury during a difficult vaginal delivery leads to pelvic organ prolapse later in life. If one could address how and why the muscle injury originates, one might be able to better prevent these injuries in the future. In a recent review we concluded that many atraumatic injuries of the muscle-tendon unit are consistent with it being weakened by an accumulation of passive tissue damage during repetitive loading. While the PVM can tear due to a single overstretch at the end of the second stage of labor we hypothesize that it can also be weakened by an accumulation of microdamage and then tear after a series of submaximal loading cycles. We conclude that there is strong indirect evidence that low cycle fatigue of PVM passive tissue is a possible mechanism of its proximal failure. This has implications for finding new ways to better prevent PVM injury in the future.

Mechanisms of pelvic floor muscle training for managing urinary incontinence in women: a scoping review.

BACKGROUND: Pelvic floor muscle training is recommended as first line treatment for urinary incontinence in women based on three proposed theorized mechanisms: 'Enhanced Pelvic Floor Muscle Strength,' 'Maximized Awareness of Timing,' and 'Strengthened Core Muscles'. The purpose of this scoping review was to systematically map evidence for and against theorized mechanisms through which pelvic floor muscle training interventions work to reduce urinary incontinence in women. METHODS: The scoping review is based upon a comprehensive search of relevant literature published from 1990 to 2020 in PubMed, CINAHL, PsycINFO, ClinialTrials.gov, reference lists from review articles, and hand searches of articles by known researchers in the field. We included English-language, peer-reviewed articles on pelvic floor muscle training as an intervention for adult women if they provided empirical evidence to testing the theorized intervention mechanisms. Two independent reviewers screened articles for inclusion and extracted data to describe details of each study (author, year, country, design, sampling), measures of pelvic floor muscle strength and urinary incontinence, statistical analysis of linkage between changes in the measures, and pelvic floor muscle training regimens. Data were summarized to facilitate the integration of diverse evidence to draw conclusions on supporting or refuting the three proposed theorized mechanisms for managing urinary incontinence in women. RESULTS: Of the 278 articles identified with the search, 13 (4.7%) met inclusion criteria. There was weak to no evidence for the mechanism of enhanced pelvic floor muscle strength, equivocal support for maximized awareness of timing, and no evidence for strengthened core muscles. CONCLUSIONS: This review revealed extremely limited data supporting the proposed theorized mechanisms underlying pelvic floor muscle training programs to manage urinary incontinence in women. Such evidence is needed to help women and clinicians understand how, why and when a woman benefits from pelvic floor muscle training. Future studies should specifically state and report statistical analysis that relates the theorized mechanisms to the training outcomes observed.

Testing a Quaternion Conversion Method to Determine Human Three-Dimensional Tibiofemoral Angles During an In Vitro Simulated Jump Landing.

Lower limb joint kinematics have been measured in laboratory settings using fixed camera-based motion capture systems; however, recently inertial measurement units (IMUs) have been developed as an alternative. The purpose of this study was to test a quaternion conversion (QC) method for calculating the three orthogonal knee angles during the high velocities associated with a jump landing using commercially available IMUs. Nine cadaveric knee specimens were instrumented with APDM Opal IMUs to measure knee kinematics in one-legged 3-4× bodyweight simulated jump landings, four of which were used in establishing the parameters (training) for the new method and five for validation (testing). We compared the angles obtained from the QC method to those obtained from a commercially available sensor and algorithm (APDM Opal) with those calculated from an active marker motion capture system. Results showed a significant difference between both IMU methods and the motion capture data in the majority of orthogonal angles (p < 0.01), though the differences between the QC method and Certus system in the testing set for flexion and rotation angles were smaller than the APDM Opal algorithm, indicating an improvement. Additionally, in all three directions, both the limits of agreement and root-mean-square error between the QC method and the motion capture system were smaller than between the commercial algorithm and the motion capture.

A Comparison of Inertial Measurement Unit and Motion Capture Measurements of Tibiofemoral Kinematics during Simulated Pivot Landings.

Injuries are often associated with rapid body segment movements. We compared Certus motion capture and APDM inertial measurement unit (IMU) measurements of tibiofemoral angle and angular velocity changes during simulated pivot landings (i.e., ~70 ms peak) of nine cadaver knees dissected free of skin, subcutaneous fat, and muscle. Data from a total of 852 trials were compared using the Bland-Altman limits of agreement (LoAs): the Certus system was considered the gold standard measure for the angle change measurements, whereas the IMU was considered the gold standard for angular velocity changes. The results show that, although the mean peak IMU knee joint angle changes were slightly underestimated (2.1° for flexion, 0.2° for internal rotation, and 3.0° for valgus), the LoAs were large, ranging from 35.9% to 49.8%. In the case of the angular velocity changes, Certus had acceptable accuracy in the sagittal plane, with LoAs of ±54.9°/s and ±32.5°/s for the tibia and femur. For these rapid motions, we conclude that, even in the absence of soft tissues, the IMUs could not reliably measure these peak 3D knee angle changes; Certus measurements of peak tibiofemoral angular velocity changes depended on both the magnitude of the velocity and the plane of measurement.

Delivering an advice and guidance service in neurology.

It is increasingly common for secondary care to provide advice to primary care without an outpatient appointment. Even before the increased telemedicine during COVID-19, many hospital services gave advice alone for some referrals, yet there are few published data about patient outcomes. Does advice and guidance alter outpatient numbers or simply mean that patients are seen later? Which neurological conditions can we manage at a distance? Do complaints increase from either primary care or patients? Do clinics become more complex and time consuming? Our department has developed an advice and guidance service embedded within the English electronic referral system since 2017, allowing detailed analysis of the outcome of 6500 patients over 2.5 years. We suggest ways to set up and run a neurology advice and guidance service, looking at the potential benefits and the barriers.

Expression patterns for Bcl-2, EMA, ß-catenin, E-cadherin, PAX8, and MIB1 in thymomas.

The expression of immunohistochemical markers has been extensively investigated in thymomas to assist in the differential diagnosis. We have studied six select markers to determine their utility in the evaluation of these tumors. A series of 126 thymomas including 33 type A, 27 type AB, 20 type B1, 22 type B2, and 24 type B3, were examined utilizing a tissue microarray (TMA) technique with antibodies to e-cadherin, ß-catenin, PAX8, bcl-2, EMA, and MIB-1. Keratin AE1/AE3 and p63 were used for quality control. A significant finding was strong and consistent positivity for bcl-2 in type A (90%) and type AB (88.8%) thymoma, while 100% of B1, B2, and B3 were negative. The distribution of e-cadherin and ß-catenin was not useful for differential diagnosis. E-cadherin and ß-catenin were expressed in a high proportion of all the tumors (92-100%), except for B2 thymoma which showed only 45% expression. A significant increase in the expression of the MIB-1 proliferation marker (mean: 12.8% nuclear positivity) was also observed in B3 thymoma compared with the other histologic types. Statistical significance was confirmed using Kruskal's non-parameterized test for distribution. EMA was generally negative except for spindle cells in the fibrous septa in types A and AB thymoma. PAX8 showed less consistent nuclear staining than p63 and was only widely expressed in 55.7% of cases. Bcl-2 may serve as a useful marker to separate spindle cell thymomas (Type A and AB) from the other types, and the MIB1 proliferation index may be of use to differentiate type B2 from type B3 thymoma.

A new 3D stress MRI measurement strategy to quantify surgical correction of prolapse in three support systems.

AIMS: The aim of this study was to develop and test the feasibility of a magnetic resonance imaging (MRI)-based measurement strategy to evaluate the effectiveness of surgical procedures in restoring normal anatomy in all three systems of pelvic floor support and quantify the structural changes induced by prolapse surgery. METHODS: Patients underwent clinical examination and stress MRI preoperatively and again 3 months postoperatively. Preoperative and postoperative measures of three MRI-based structural support systems were made: (1) vaginal wall, (2) apical and paravaginal support, and (3) hiatal closure system. Preoperative to postoperative structural changes were calculated and compared to normal values, and bivariate associations were determined. RESULTS: The three structural support systems were successfully quantified for both preoperative and postoperative MRIs regardless of operative approaches in all 15 women in the pilot group. Apical support was restored to normal in 11 of 12 patients who underwent an apical suspension procedure and 9 of 14 patients with a posterior repair had normalization of genital hiatus size. Mid-vaginal paravaginal location was elevated an average of 2.5 ± 2.0 cm despite no paravaginal repairs being performed. Paravaginal location improvements were also significantly correlated with apical elevation (r values 0.99-0.87, p < 0.001). CONCLUSIONS: A strategy that quantifies structural-specific preoperative impairments and improvements after prolapse surgery was successfully developed. Early findings reveal that prolapse surgery is more successful in restoring normal anatomy at Level I than Level III. Improvement in paravaginal location is significantly correlated with apical elevation.

Feasibility of a deep learning-based method for automated localization of pelvic floor landmarks using stress MR images.

INTRODUCTION AND HYPOTHESIS: Magnetic resonance imaging (MRI) plays an important role in assessing pelvic organ prolapse (POP), and automated pelvic floor landmark localization potentially accelerates MRI-based measurements of POP. Herein, we aimed to develop and evaluate a deep learning-based technique for automated localization of POP-related landmarks. METHODS: Ninety-six mid-sagittal stress MR images (at rest and at maximal Valsalva) were used for deep-learning model training and generalization testing. We randomly split our dataset into a training set of 73 images and a testing set of 23 images. One soft-tissue landmark (the cervical os [P1]) and three bony landmarks (the mid-pubic line [MPL] endpoints [P2&P3] and the sacrococcygeal inferior-pubic point [SCIPP] line endpoints [P3&P4]) were annotated by experts. We used an encoder-decoder structure to develop the deep learning model for automated localization of the four landmarks. Localization performance was assessed using the root square error (RSE), whereas the reference lines were assessed based on the length and orientation differences. RESULTS: We localized landmarks (P1 to P4) with mean RSEs of 1.9 mm, 1.3 mm, 0.9 mm, and 3.6 mm. The mean length errors of the MPL and SCIPP line were 0.1 and -2.1 mm, and the mean orientation errors of the MPL and SCIPP line were -0.7° and -0.3°. Our method predicted each image in 0.015 s. CONCLUSIONS: We demonstrated the feasibility of a deep learning-based approach for accurate and fast fully automated localization of bony and soft-tissue landmarks. This sped up the MR interpretation process for fast POP screening and treatment planning.

Structural failure sites in posterior vaginal wall prolapse: stress 3D MRI-based analysis.

INTRODUCTION AND HYPOTHESIS: The objective was to identify structural failure sites in rectocele by comparing women with and those without posterior vaginal wall prolapse and accessing their relative contribution to rectocele size based on stress MRI-based measurements. METHODS: We studied three-dimensional stress MRI at maximal Valsalva of 25 women with (cases) and 25 without (controls) posterior vaginal prolapse of similar age and parity. Vaginal wall factors (posterior wall length and width); attachment factors (paravaginal posterior wall location, posterior fornix height, and perineal height); and hiatal factors (hiatal size and levator ani defects) were measured using Slicer 4.3.0® and a custom Python program. Stepwise linear regression was used to assess the relative contribution of all factors to the posterior prolapse size. RESULTS: We identified three primary factors with large effect sizes of 2 or greater: two attachment factors-posterior paravaginal descent and perineal height; and one hiatal factor-genital hiatus size. These were the strongest predictors of the presence and size of rectocele, the most common failure sites, found in 60-76% of cases; and highly correlated with one another (r = 0.72-0.84, p < .001). Longer vaginal length, wider distal vagina, lower posterior fornix, and larger levator ani hiatus had smaller effect sizes and were less likely to fall outside the norm (20-24%) than the three primary factors. When considering all the supporting factors, the combination of perineal height, posterior fornix height, and vaginal length explained 73% of the variation in rectocele size. CONCLUSIONS: Lower perineal and lateral posterior vaginal location and enlarged genital hiatus size were strong predictors of rectocele occurrence and size and correlated highly.

Mechanisms of hiatus failure in prolapse: a multifaceted evaluation.

INTRODUCTION AND HYPOTHESIS: We investigated whether factors influencing pelvic floor hiatal closure are inter-related or independent, hypothesizing that (1) hiatus size is moderately correlated with levator defect, pelvic floor muscle strength, and change in hiatus size with contraction and (2) urogenital hiatus (UGH) and levator hiatus (LH) measures are similar in patients with anterior wall (AW) and posterior wall (PW) prolapse. METHODS: This cross-sectional case-control study included subjects with AW prolapse (n = 50), PW prolapse (n = 50), and normal support (n = 50). Hiatus measurements and levator defects were assessed on MRI, and vaginal closure force was measured with an instrumented speculum. Pearson correlation coefficients and simple and multivariable linear regression models were performed. RESULTS: During contraction, LH narrowed 47% more in the PW compared to AW group (p = 0.001). With straining, LH lengthened 34% more in the PW than AW group (p < 0.001). With straining, UGH and LH lengthening was greater by 72% and 44% in those with major compared to no/minor defect (p < 0.001 and p = 0.004). Contraction strength explained, at most, 4% of UGH (r = 0.17) or LH (r = 0.20) shortening during contraction (r = 0.17 and r = 0.20, respectively), indicating that these factors are largely independent. After controlling for prolapse size, resting UGH and levator defect status were associated with straining UGH (p < 0.001, p = 0.004), but muscle strength and resting tone were not. CONCLUSIONS: Hiatus measures are complex and differ according to prolapse occurrence and type. They are, at best, only weakly correlated with pelvic floor muscle strength and movement during contraction.