Preoperative prolapse phenotype is predictive of surgical outcome with minimally invasive sacrocolpopexy.

BACKGROUND: The gold-standard treatment for advanced pelvic organ prolapse is sacrocolpopexy. However, the preoperative features of prolapse that predict optimal outcomes are unknown. OBJECTIVE: This study aimed to develop a clinical prediction model that uses preoperative scores on the Pelvic Organ Prolapse Quantification examination to predict outcomes after minimally invasive sacrocolpopexy for stages 2, 3, and 4 uterovaginal prolapse and vaginal vault prolapse. STUDY DESIGN: A 2-institution database of pre- and postoperative variables from 881 cases of minimally invasive sacrocolpopexy was analyzed. Data from patients were analyzed in the following 4 groups: stage 2 uterovaginal prolapse, stage 3 to 4 uterovaginal prolapse, stage 2 vaginal vault prolapse, and stage 3 to 4 vaginal vault prolapse. Unsupervised machine learning was used to identify clusters and investigate associations between clusters and outcome. The k-means clustering analysis was performed with preoperative Pelvic Organ Prolapse Quantification points and stratified by previous hysterectomy status. The "optimal" surgical outcome was defined as postoperative Pelvic Organ Prolapse Quantification stage <2. Demographic variables were compared by cluster with Student t and chi-square tests. Odds ratios were calculated to determine whether clusters could predict the outcome. Age at surgery, body mass index, and previous prolapse surgery were used for adjusted odds ratios. RESULTS: Five statistically distinct prolapse clusters (phenotypes C, A, A>P, P, and P>A) were found. These phenotypes reflected the predominant region of prolapse (apical, anterior, or posterior) and whether support was preserved in the nonpredominant region. Phenotype A (anterior compartment prolapse predominant, posterior support preserved) was found in all 4 groups of patients and was considered the reference in the analysis. In 111 patients with stage 2 uterovaginal prolapse, phenotypes A and A>P (greater anterior prolapse than posterior prolapse) were found, and patients with phenotype A were more likely than those with phenotype A>P to have an optimal surgical outcome. In 401 patients with stage 3 to 4 uterovaginal prolapse, phenotypes C (apical compartment predominant, prolapse in all compartments), A, and A>P were found, and patients with phenotype A>P were more likely than those with phenotype A to have ideal surgical outcome. In 72 patients with stage 2 vaginal vault prolapse, phenotypes A, A>P, and P (posterior compartment predominant, anterior support preserved) were found, and those with phenotype A>P were less likely to have an ideal outcome than patients with phenotype A. In 297 patients with stage 3 to 4 vaginal vault prolapse, phenotypes C, A, and P>A (prolapse greater in posterior than in anterior compartment) were found, but there were no significant differences in rate of ideal outcome between phenotypes. CONCLUSION: Five anatomic phenotypes based on preoperative Pelvic Organ Prolapse Quantification scores were present in patients with stages 2 and 3 to 4 uterovaginal prolapse and vaginal vault prolapse. These phenotypes are predictive of surgical outcome after minimally invasive sacrocolpopexy. Further work needs to confirm the presence and predictive nature of these phenotypes. In addition, whether the phenotypes represent a progression of prolapse or discrete prolapse presentations resulting from different anatomic and life course risk profiles is unknown. These phenotypes may be useful in surgical counseling and planning.

Pubococcygeal Line Versus H-line as MR Defecography Reference for Bladder Descent.

INTRODUCTION AND HYPOTHESIS: Magnetic resonance defecography imaging techniques have been used widely to study pelvic floor function and diagnose pelvic organ prolapse (POP). The aim of this study was to investigate the diagnostic accuracy of the H-line to detect bladder descent compared with the current landmark, the pubococcygeal line (PCL). METHODS: In this retrospective cohort study, patients who underwent MR defecography in our medical center and were diagnosed with moderate to severe cystocele by radiological measurements were recruited. One rest image and one maximum evacuation image for each subject were used for the following measurements: bladder base perpendicular distance from the genital hiatus (GH), indicative of clinically significant bladder descent, PCL as the current radiological reference line, and the H-line, or minimal levator hiatus line, indicative of pelvic floor muscle and connective tissue support. Subjects were categorized as having clinically significant cystocele if the "bladder base" reached within 1 cm or lower of the GH (stage II or higher cystocele). A comparison was performed to assess differences and predictive capabilities of the reference lines relative to the GH measure. RESULTS: Seventy subjects were included, 30 with clinically significant bladder descent based on distance to GH. Women with bladder descent were older (64.0 ± 11.8 vs 51.2 ± 15.6, p < 0.001), had increased parity (3 [1-7] vs 2 [0-5], p = 0.009), and had a bladder that descended lower than the H-line at rest (1.9 ± 0.5 vs 2.2 ± 0.4, p = 0.003) and evacuation (-2.4 ± 1.6 vs -0.7 ± 1.1, p < 0.001). Multivariate regression analysis confirmed that age, length of the H-line at evacuation, the perpendicular distances between the H-line and the lowest bladder point at rest, and the PCL to the lowest bladder point at evacuation significantly correlated with bladder descent. Receiver operating characteristic analysis was used to identify a measurement threshold to diagnose clinically significant cystocele for both measurements, bladder base to the H-line: -1.2 (80.0, 72.5) area under the curve (AUC) 0.82, and bladder base PCL: -3.3 (77.8, 79.5) AUC 0.86. CONCLUSION: Our data support the application of using the minimal levator hiatus plane and specifically the H-line as a reliable landmark to diagnose bladder descent using MR defecography imaging.

Pregnancy-induced remodeling of the murine reproductive tract: a longitudinal in vivo magnetic resonance imaging study.

Mammalian pregnancy requires gradual yet extreme remodeling of the reproductive organs to support the growth of the embryos and their birth. After delivery, the reproductive organs return to their non-pregnant state. As pregnancy has traditionally been understudied, there are many unknowns pertaining to the mechanisms behind this remarkable remodeling and repair process which, when not successful, can lead to pregnancy-related complications such as maternal trauma, pre-term birth, and pelvic floor disorders. This study presents the first longitudinal imaging data that focuses on revealing anatomical alterations of the vagina, cervix, and uterine horns during pregnancy and postpartum using the mouse model. By utilizing advanced magnetic resonance imaging (MRI) technology, T1-weighted and T2-weighted images of the reproductive organs of three mice in their in vivo environment were collected at five time points: non-pregnant, mid-pregnant (gestation day: 9-10), late pregnant (gestation day: 16-17), postpartum (24-72 h after delivery) and three weeks postpartum. Measurements of the vagina, cervix, and uterine horns were taken by analyzing MRI segmentations of these organs. The cross-sectional diameter, length, and volume of the vagina increased in late pregnancy and then returned to non-pregnant values three weeks after delivery. The cross-sectional diameter of the cervix decreased at mid-pregnancy before increasing in late pregnancy. The volume of the cervix peaked at late pregnancy before shortening by 24-72 h postpartum. As expected, the uterus increased in cross-sectional diameter, length, and volume during pregnancy. The uterine horns decreased in size postpartum, ultimately returning to their average non-pregnant size three weeks postpartum. The newly developed methods for acquiring longitudinal in vivo MRI scans of the murine reproductive system can be extended to future studies that evaluate functional and morphological alterations of this system due to pathologies, interventions, and treatments.

Vaginal morphology and position associated with prolapse recurrence after vaginal surgery: A secondary analysis of the DEMAND study.

OBJECTIVE: To identify vaginal morphology and position factors associated with prolapse recurrence following vaginal surgery. DESIGN: Secondary analysis of magnetic resonance images (MRI) of the Defining Mechanisms of Anterior Vaginal Wall Descent cross-sectional study. SETTING: Eight clinical sites in the US Pelvic Floor Disorders Network. POPULATION OR SAMPLE: Women who underwent vaginal mesh hysteropexy (hysteropexy) with sacrospinous fixation or vaginal hysterectomy with uterosacral ligament suspension (hysterectomy) for uterovaginal prolapse between April 2013 and February 2015. METHODS: The MRI (rest, strain) obtained 30-42 months after surgery, or earlier for participants with recurrence who desired reoperation before 30 months, were analysed. MRI-based prolapse recurrence was defined as prolapse beyond the hymen at strain on MRI. Vaginal segmentations (at rest) were used to create three-dimensional models placed in a morphometry algorithm to quantify and compare vaginal morphology (angulation, dimensions) and position. MAIN OUTCOME MEASURES: Vaginal angulation (upper, lower and upper-lower vaginal angles in the sagittal and coronal plane), dimensions (length, maximum transverse width, surface area, volume) and position (apex, mid-vagina) at rest. RESULTS: Of the 82 women analysed, 12/41 (29%) in the hysteropexy group and 22/41 (54%) in the hysterectomy group had prolapse recurrence. After hysteropexy, women with recurrence had a more laterally deviated upper vagina (p = 0.02) at rest than women with successful surgery. After hysterectomy, women with recurrence had a more inferiorly (lower) positioned vaginal apex (p = 0.01) and mid-vagina (p = 0.01) at rest than women with successful surgery. CONCLUSIONS: Vaginal angulation and position were associated with prolapse recurrence and suggestive of vaginal support mechanisms related to surgical technique and potential unaddressed anatomical defects. Future prospective studies in women before and after prolapse surgery may distinguish these two factors.

Sacrum and Coccyx Shape Changes During Pregnancy and After Delivery.

Remodeling of the sacrum and coccyx to accommodate pregnancy and delivery has been hypothesized but not directly quantified. This study aimed to quantify the remodeling of the sacrum and coccyx by comparing midsagittal lengths, angles, curvature, and shape between nulliparous, pregnant, and parous women using both 2 and 3 dimensional measures. Ninety pelvic magnetic resonance images of the pelvis were retrospectively collected and segmented. Twelve length, angle, and curvature measurements were made using definitions from previous literature on the midsagittal plane to define the sacrum, coccyx, and combined sacrum-coccyx shape. These measures were followed by a statistical shape analysis, which returned modes of variation and principal component scores. A separate MANCOVA analysis was conducted for both the 2D and 3D measures. The 2D and 3D analyses agreed that pregnant women had a significantly straighter coccyx and combined sacrum/coccyx than nulliparous (9.1% and 5.6%, respectively) and parous (7.5% and 2.7%, respectively) subjects. All comparisons showed that, on average, a pregnant woman's sacrum and coccyx were significantly straighter than their nulliparous counterparts. Then after delivery, the sacrum/coccyx returned, but not completely back to a more curved configuration.

Quantifying the effect of an endo-vaginal probe on position of the pelvic floor viscera and muscles.

INTRODUCTION AND HYPOTHESIS: Endovaginal ultrasound has long been hypothesized to have a significant effect on locations of what it visualizes. However, little work has directly quantified its effect. This study aimed to quantify it. METHODS: This cross-sectional study consisted of 20 healthy asymptomatic volunteers who underwent both endovaginal ultrasound and MRI. The urethra, vagina, rectum, pelvic floor, and pubic bone were segmented in both ultrasound and MRI using 3DSlicer. Then, using 3DSlicer's transform tool the volumes were rigidly aligned based on the posterior curvature of the pubic bone. The organs were then split into thirds along their long axis to compare their distal, middle, and proximal sections. Using Houdini, we compared the location of the centroid of each of the urethra, vagina, and rectum and the surface-to-surface difference of the urethra and rectum. The anterior curvature of the pelvic floor was also compared. Normality of all variables was assessed by Shapiro-Wilk test. RESULTS: The largest amount of surface-to-surface distance was observed in the proximal region for the urethra and rectum. Across all three organs, the majority of the deviation was in the anterior direction for geometries obtained from ultrasound versus those from MRI. For each subject, the trace defining the midline of the levator plate was more anterior for ultrasound compared to MRI. CONCLUSIONS: While it has often been assumed that placing a probe in the vagina probably distorts the anatomy, this study quantified the distortion and displacement of the pelvic viscera. This allows for better interpretation of clinical and research findings based on this modality.

Effect of Squeeze, Cough, and Strain on Dynamic Urethral Function in Nulligravid Asymptomatic Women: A Cross-Sectional Cohort Study.

IMPORTANCE: In the past, urethral shape, mobility, and urodynamics have been used to retrospectively demonstrate correlations with stress urinary incontinence. Our previous work has shown a relationship between urethral function and shape in symptomatic women. OBJECTIVE: This study aimed to characterize the effect of pelvic floor squeeze and strain maneuvers on urethral shapes and pressure in a cohort of patients without pelvic floor disorders. STUDY DESIGN: In this cross-sectional study, volunteers underwent dynamic pelvic floor ultrasound examination, and a modified urodynamic study. Urethral length, thickness, and proximal and distal swing angles were measured at rest, squeeze, and strain. The midsagittal urethral walls were traced so that a statistical shape model could be performed. Means and standard deviations of imaging and urodynamic measures were calculated. RESULTS: Data from 19 participants were analyzed. On average during squeeze compared with rest, urethral length increased by 6%, thickness decreased by 42% (distal, P < 0.001), 10% (middle), and urethral pressure increased by 14%. Opposite shape changes-length decreased by 10% ( P = 0.001), thickness increased by 57% (distal, P < 0.001), 20% (middle, P < 0.001)-and increased urethral mobility were observed during strain, with larger pressure increases occurring (29%, P < 0.001). Fifty-one percent of the total shape variance described the differences between maneuvers. These differences were statistically different between groups ( P < 0.001 for comparisons, all others P > 0.05). CONCLUSIONS: Dynamic ultrasound and urodynamics allow for the establishment of baseline ranges in urethral metrics (2-dimensional measures, shape, and pressure) and how they are altered during maneuvers. These data can allow for a more objective identification of incontinence via ultrasound and urodynamic testing.

Multimodal measurements of levator bowl volume in nulligravid asymptomatic women: endovaginal ultrasound versus MRI.

INTRODUCTION AND HYPOTHESIS: Measurements of levator bowl volume using advanced imaging, may be predictive of pelvic floor muscle function. The aim of this study was to compare the volume of the levator bowl using both magnetic resonance imaging (MRI) and endovaginal ultrasound (EVU) of healthy asymptomatic women. METHODS: All participants underwent a comprehensive interview including completion of the Pelvic Floor Distress Inventory Questionnaire-20 questionnaire, pelvic examination with a pelvic organ prolapse quantification evaluation, MRI, and EVU. The pelvic floor was segmented using Slicer and the MRI segmentations were trimmed using two methods: soft-tissue landmarks and the field of view (FOV) of the ultrasound volume. The levator bowl volume of the 3D segmented shapes was measured using Blender's 3D printing toolkit. Normality was tested using the Shapiro-Wilks test and comparisons were made using self-paired t tests. RESULTS: The final analysis included 19 patients. Levator bowl volume measured via MRI was larger than that measured in EVU (46.1 ± 7.9 cm3 vs 27.4 ± 5.9 cm3, p<0.001). Reducing the FOV of the MRI to that of EVU caused the MRI volume to be much closer to the EVU volume (35.5 ± 3.3 cm3 vs 27.4 ± 5.9 cm3, p<0.001); however, it remained significantly larger. CONCLUSION: Levator bowl volume measured using MRI was larger than that measured using EVU no matter the method of delineation of the levator muscles. Although EVU is safe, cheap, and easy to perform, it captures a smaller volume of levator bowel than MRI.

Morphological Variation in the Pelvic Floor Muscle Complex of Nulliparous, Pregnant, and Parous Women.

Specific levator ani muscle imaging measures change with pregnancy and vaginal parity, though entire pelvic floor muscle complex (PFMC) shape variation related to pregnancy-induced and postpartum remodeling has never been quantified. We used statistical shape modeling to compute the 3D variation in PFMC morphology of reproductive-aged nulliparous, late pregnant, and parous women. Pelvic magnetic resonance images were collected retrospectively and PFMCs were segmented. Modes of variation and principal component scores, generated via statistical shape modeling, defined significant morphological variation. Nulliparous (have never given birth), late pregnant (3rd trimester), and parous (have given birth and not currently pregnant) PFMCs were compared via MANCOVA. The overall PFMC shape, mode 2, and mode 3 significantly differed across patient groups (p < 0.001, = 0.002, = 0.001, respectively). This statistical shape analysis described greater perineal and external anal sphincter descent, increased iliococcygeus concavity, and a proportionally wider mid-posterior levator hiatus in late pregnant compared to nulliparous and parous women. The late pregnant group was the most divergent, highlighting differences that likely reduce the mechanical burden of vaginal childbirth. This robust quantification of PFMC shape provides insight to pregnancy and postpartum remodeling and allows for generation of representative non-patient-specific PFMCs that can be used in biomechanical simulations.

Quantifying the physiologic motions of the pelvic viscera during evacuation in nulligravid asymptomatic women.

INTRODUCTION AND HYPOTHESIS: Pelvic organ prolapse (POP) is often diagnosed during an in-office examination, which looks for motion of the vaginal wall while performing a strain maneuver. It is believed that the pelvic organs in adequately supported women are relatively stationary. This study was aimed at investigating the physiological displacements of pelvic organs using MR defecography. METHODS: This prospective cohort study included 19 volunteers. Midsagittal slices representing rest and the maximum movement of the posterior vaginal fornix during three maneuvers were identified. Normalized axes for analysis were defined as the x' (line connecting the inferior-posterior-most point on the pubic symphysis to the anterior edge of the sacrococcygeal joint) and the y' (line orthogonal to the x axis that passed through the sacral promontory). The positions of the posterior vaginal fornix, mid-vagina, bladder neck, anorectal junction, and hymen were recorded. These subjects were then analyzed using the current radiological grading system of POP to determine any overlap between asymptomatic subjects and diagnostic ranges of POP. RESULTS: Evacuation caused the most motion in the landmarks. The majority of the motion of the landmarks was along the y axis. The posterior vaginal fornix experienced significant descent (125% of the initial distance) without much anterior-posterior translation (7% of the initial distance) during defecation. All landmarks experienced similar trends. CONCLUSIONS: We have shown that there is significant rotational motion of the pelvic organs around the pubic bone in adequately supported women. This motion when described using radiological grading is likely to be considered mild or moderate prolapse, which may contribute to overdiagnosis of POP.

A Computational Procedure to Derive the Curve of Carus for Childbirth Computational Modeling.

Computational modeling serves an important role in childbirth-related research. Prescribed fetal descent trajectory is a key characteristic in childbirth simulations. Two major types of fully prescribed fetal descent trajectories can be identified in the literature: straight descent trajectories and curve of Carus. The straight descent trajectory has the advantage of being simpler and can serve as a reasonable approximation for relatively small fetal movements during labor, but it cannot be used to simulate the entire childbirth process. The curve of Carus is the well-recognized fetal descent trajectory with physiological significance. However, no detailed procedure to geometrically define the curve of Carus can be found in existing computational studies. This status of curve of Carus simulation in the literature hinders the direct comparison of results across different studies and the advancement of computational techniques built upon previous research. The goals of this study are: (1) propose a universal approach to derive the curve of Carus for the second stage of labor, from the point when the fetal head engages the pelvis to the point when the fetal head is fully delivered; and (2) demonstrate its utility when considering various fetal head sizes. The current study provides a detailed formulation of the curve of Carus, considering geometries of both the mother and the fetus. The maternal geometries were obtained from MRI data, and the fetal head geometries were based on laser scanning of a replica of a real fetal head.

3D quantitative analysis of normal clitoral anatomy in nulliparous women by MRI.

INTRODUCTION AND HYPOTHESIS: We present a 3D computational approach for automated clitoral measurements. We hypothesized that computationally derived measurements would be comparable and less variable than reported manual measures. METHODS: In this retrospective study, MRIs of 22 nulliparous women age 20-49 years with normal vaginal and clitoral anatomy were collected. Manual segmentations were performed to reconstruct 3D models of the whole clitoris (glans, body, crura, and bulbs) and vagina. The length, width, and volume of the clitoral structures and the distance between the vagina and clitoral structures were calculated. Computed clitoral morphometrics (length, width) were compared to median [range] values from a previously published cadaver study (N = 22) using the median test and Moses extreme reaction test. Calculated distances were compared to mean (± SD) reported by a 2D MRI study (N = 20) using independent t-test and Levene's test. RESULTS: Overall, computed clitoral morphometrics were similar to manual cadaver measurements, where the majority of length and width measures had ~1-2 mm difference and had less variability (smaller range). All calculated distances were significantly smaller and had smaller SDs than manual 2D MRI values, with two-fold differences in the means and SDs. Large variation was observed in clitoral volumetric measures in our cohort. CONCLUSIONS: The proposed 3D computational method improves the standardization and consistency of clitoral measurements compared to traditional manual approaches. The use of this approach in radiographic studies will give better insight into how clitoral anatomy relates to sexual function and how both are impacted by gynecologic surgery, where outcomes can assist treatment planning.

Smooth Muscle Organization and Nerves in the Rat Vagina: A First Look Using Tissue Clearing and Immunolabeling.

Smooth muscle fibers within the vagina, as well as the nerve fibers that contribute to their control mechanisms, are important for the maintenance and alteration of vaginal length and tone. Vaginal smooth muscle (VaSM) is typically described as being arranged into two distinct concentric layers: an inner circular muscular layer and an outer longitudinal muscular layer. However, the distribution of VaSM oriented in the longitudinal direction (LD) and circumferential direction (CD) has never been quantified. In this study, tissue clearing and immunohistochemistry were performed so that the VaSM, and surrounding nerves, within whole rat vaginas ([Formula: see text]) could be imaged without tissue sectioning, preserving the three-dimensional architecture of the organs. Using these methods, the vagina was viewed through the full thickness of the muscularis layer, from the distal to the proximal regions. The VaSM orientation in the proximal and distal regions and the VaSM content along the LD and CD were quantified. Additionally, a qualitative assessment of vaginal nerves was performed. When compared using a permuted version of the Watson [Formula: see text] test, the orientation of VaSM in the proximal and distal regions were found to be significantly different in 4 of the 6 imaged rat vaginas ([Formula: see text]). While the distal vagina contained a similar amount of VaSM oriented within [Formula: see text] of the LD and within [Formula: see text] of the CD, the proximal vagina contained significantly more VaSM oriented towards the LD than towards the CD. Nerve fibers were found to be wavy, running both parallel and perpendicular to vascular and non-vascular smooth muscle within the vagina. Micro-structural analyses, like the one conducted here, are necessary to understand the physiological function and pathological changes of the vagina.

Urethral support in female urinary continence part 1: dynamic measurements of urethral shape and motion.

INTRODUCTION AND HYPOTHESIS: Urethral closure mechanism dysfunction in female stress urinary incontinence (SUI) is poorly understood. We aimed to quantify these mechanisms through changes in urethral shape and position during squeeze (voluntary closure) and Valsalva (passive closure) via endovaginal ultrasound in women with varying SUI severity. METHODS: In this prospective cohort study, 76 women who presented to our tertiary center for urodynamic testing as preoperative assessment were recruited. Urodynamics were performed according to International Continence Society criteria. Urethral pressures were obtained during serial Valsalva maneuvers. Urethral lengths, thicknesses, and angles were measured in the midsagittal plane via dynamic anterior compartment ultrasound. Statistical shape modeling was carried out by a principal component analysis on aligned urethra shapes. RESULTS: Age, parity, and BMI did not vary by SUI group. Ultrasound detected a larger retropubic angle, urethral knee-pubic bone angle (a novel measure developed for this study), and infrapubic urethral length measurements at Valsalva in women with severe SUI (p = 0.016, 0.015, and 0.010). Shape analysis defined increased "c" shape concavity and distal wall pinching during squeeze and increased "s" shape concavity and distal wall thickening during Valsalva (p < 0.001). It also described significant urethral shape differences across SUI severity groups (p < 0.001). CONCLUSIONS: Dynamic endovaginal ultrasound can visualize and allow for quantification of voluntary and passive urethral closure and variations with SUI severity. In women with severe SUI, excessive bladder neck and distal urethra swinging during Valsalva longitudinally compressed the urethra, resulting in a proportionally thicker wall at the mid-urethra and urethral knee.

A soft elastomer alternative to polypropylene for pelvic organ prolapse repair: a preliminary study.

INTRODUCTION AND HYPOTHESIS: We compared the impact of a mesh manufactured from the soft elastomer polydimethylsiloxane (PDMS) to that of a widely used lightweight polypropylene (PP) mesh. To achieve a similar overall device stiffness between meshes, the PDMS mesh was made with more material and therefore was heavier and less porous. We hypothesized that the soft polymer PDMS mesh, despite having more material, would have a similar impact on the vagina as the PP mesh. METHODS: PDMS and PP meshes were implanted onto the vaginas of 20 rabbits via colpopexy. Ten rabbits served as sham. At 12 weeks, mesh-vagina complexes were explanted and assessed for contractile function, histomorphology, total collagen, and glycosaminoglycan content. Outcome measures were compared using one-way ANOVA and Kruskal-Wallis testing with appropriate post-hoc testing. RESULTS: Relative to sham, vaginal contractility was reduced following the implantation of PP (p = 0.035) but not the softer PDMS (p = 0.495). PP had an overall greater negative impact on total collagen and glycosaminoglycan content, decreasing by 53% (p < 0.001) and 54% (p < 0.001) compared to reductions of 35% (p = 0.004 and p < 0.001) with PDMS. However, there were no significant differences in the contractility, collagen fiber thickness, total collagen, and glycosaminoglycan content between the two meshes. CONCLUSIONS: Despite having a substantially higher weight, PDMS had a similar impact on the vagina compared to a low-weight PP mesh, implicating soft polymers as potential alternatives to PP. The notion that heavyweight meshes are associated with a worse host response is not applicable when comparing across materials.

Obstructed Defecation Symptom Severity and Degree of Rectal Hypermobility and Folding Detected by Dynamic Ultrasound.

ABSTRACT: We used dynamic pelvic floor ultrasound to investigate the relationship between obstructed defecation symptom (ODS) severity and the degree of rectal hypermobility/folding. In this retrospective study, women who presented with ODS from October 2017 to January 2019 and underwent an interview, pelvic examination, and pelvic floor ultrasound were recruited. Patients were diagnosed with abdominal constipation, dyssynergia, or pelvic constipation. Pelvic constipation patients were categorized based on their reported frequency of incomplete emptying of stool (<50% or ≥50% of bowel movements) representing mild and severe ODS, respectively. Using dynamic ultrasound, rectal hypermobility was quantified via rectovaginal septum length at rest and Valsalva and its compression ratio, where shorter lengths and larger compression ratios are indicative of increased rectal hypermobility. One hundred twenty-one patients (41 with abdominal constipation, 7 with dyssynergia, and 73 with pelvic constipation) were included. Compression ratios were higher in women with severe versus mild ODS (17.36 ± 16.89 vs 36.38 ± 25.82, P = 0.0039). The risk of having severe symptoms was 4 times greater (odds ratio = 4.2, 95% confidence interval = 1.4 to 12.6, P = 0.01) among those with a high compression ratio (≥20%) after controlling for age, body mass index, and levator plate descent angle. Incomplete emptying was weakly, positively, linearly correlated with rectal hypermobility/folding (r = -0.2724, -0.3767 to 0.3922, and P = 0.0197, 0.0010, 0.0006, respectively). Women with more severe ODS experienced more rectal hypermobility/folding as measured via dynamic ultrasound-a cheaper, effective alternative to magnetic resonance defecography for evaluation of obstructed defecation.

The establishment of a 3D anatomical coordinate system for defining vaginal axis and spatial position.

BACKGROUND AND OBJECTIVE: Pelvic organ prolapse (POP), the herniation of the pelvic organs toward the vaginal opening, is a common pelvic floor disorder (PFD) whose etiology is poorly understood. Traditional methods for evaluating POP are often constrained to external vaginal examination, limited to 2D, or have poor reproducibility. We propose a reliable 3D anatomic coordinate system for standardized 3D assessment of pelvic anatomy using magnetic resonance imaging (MRI). METHODS: The novel 3D anatomic reference system is based on six bony landmarks of the pelvis manually identified in MRI: the ischial spines and the superior and inferior pubic points of the left and right pubic symphysis. The origin of this system is defined as the midpoint of the ischial spines. The reproducibility and applicability of the pelvic coordinate system were evaluated by (1) implementing it in a new method to quantify vaginal position and axis (angulation) in 3D space from MRI segmentations of the vagina and (2) computing the intraclass correlation (ICC) on coordinate system and vaginal measures. The MRI analysis was performed by four non-medically trained observers on five pelvic MRI datasets on approximately five separate occasions. RESULTS: Overall, all bony landmarks had excellent intra-observer reliability and inter-observer reliability (ICC>0.90); intra-observer reliability was moderate-to-good among the vaginal position parameters (0.5

Defining mechanisms of recurrence following apical prolapse repair based on imaging criteria.

BACKGROUND: Prolapse recurrence after transvaginal surgical repair is common; however, its mechanisms are ill-defined. A thorough understanding of how and why prolapse repairs fail is needed to address their high rate of anatomic recurrence and to develop novel therapies to overcome defined deficiencies. OBJECTIVE: This study aimed to identify mechanisms and contributors of anatomic recurrence after vaginal hysterectomy with uterosacral ligament suspension (native tissue repair) vs transvaginal mesh (VM) hysteropexy surgery for uterovaginal prolapse. STUDY DESIGN: This multicenter study was conducted in a subset of participants in a randomized clinical trial by the Eunice Kennedy Shriver National Institute of Child Health and Human Development Pelvic Floor Disorders Network. Overall, 94 women with uterovaginal prolapse treated via native tissue repair (n=48) or VM hysteropexy (n=46) underwent pelvic magnetic resonance imaging at rest, maximal strain, and poststrain rest (recovery) 30 to 42 months after surgery. Participants who desired reoperation before 30 to 42 months were imaged earlier to assess the impact of the index surgery. Using a novel 3-dimensional pelvic coordinate system, coregistered midsagittal images were obtained to assess study outcomes. Magnetic resonance imaging-based anatomic recurrence (failure) was defined as prolapse beyond the hymen. The primary outcome was the mechanism of failure (apical descent vs anterior vaginal wall elongation), including the frequency and site of failure. Secondary outcomes included displacement of the vaginal apex and perineal body and change in the length of the anterior wall, posterior wall, vaginal perimeter, and introitus of the vagina from rest to strain and rest to recovery. Group differences in the mechanism, frequency, and site of failure were assessed using the Fisher exact tests, and secondary outcomes were compared using Wilcoxon rank-sum tests. RESULTS: Of the 88 participants analyzed, 37 (42%) had recurrent prolapse (VM hysteropexy, 13 of 45 [29%]; native tissue repair, 24 of 43 [56%]). The most common site of failure was the anterior compartment (VM hysteropexy, 38%; native tissue repair, 92%). The primary mechanism of recurrence was apical descent (VM hysteropexy, 85%; native tissue repair, 67%). From rest to strain, failures (vs successes) had greater inferior displacement of the vaginal apex (difference, -12 mm; 95% confidence interval, -19 to -6) and perineal body (difference, -7 mm; 95% confidence interval, -11 to -4) and elongation of the anterior vaginal wall (difference, 12 mm; 95% confidence interval, 8-16) and vaginal introitus (difference, 11 mm; 95% confidence interval, 7-15). CONCLUSION: The primary mechanism of prolapse recurrence following vaginal hysterectomy with uterosacral ligament suspension or VM hysteropexy was apical descent. In addition, greater inferior descent of the vaginal apex and perineal body, lengthening of the anterior vaginal wall, and increased size of the vaginal introitus with strain were associated with anatomic failure. Further studies are needed to provide additional insight into the mechanism by which these factors contribute to anatomic failure.

Strains induced in the vagina by smooth muscle contractions.

The ability of the vagina to contract gives rise to a set of active mechanical properties that contribute to the complex function of this organ in-vivo. Regional differences in the morphology of the vagina have been long recognized, but the large heterogeneous deformations that the vagina experiences during contractions have never been quantified. Furthermore, there is no consensus regarding differences in contractility along the two primary anatomical directions of the vagina: the longitudinal direction (LD) and the circumferential direction (CD). In this study, square vaginal specimens from healthy virgin rats (n=15) were subjected to isometric planar biaxial tests at four equi-biaxial stretches of 1.0, 1.1, 1.2, and 1.3. Contractions were induced at each stretch by a high concentration potassium solution. The digital image correlation method was used to perform full-field strain measurements during contractions. The vagina was found to undergo significantly higher compressive strains, tensile strains, and contractile forces along the LD than along the CD during contractions. Specifically, when computed over all the applied equi-biaxial stretches, mean (± std. dev.) absolute maximum compressive strains were -(13.43 ± 1.56)% along the LD and -(3.19 ± 0.25)% along the CD, mean absolute maximum tensile strains were (10.92 ± 1.73)% along the LD and (3.62 ± 0.57)% along the CD, and mean maximum contractile forces were 6.24 ± 0.55 mN along the LD and 3.35 ± 0.56 mN along the CD. Moreover, the vaginal tissue appeared to undergo compression in the proximal region and tension in the distal region while kept at constant equi-biaxial stretches. The active mechanical properties of the healthy vagina need to be fully investigated so that detrimental alterations in vaginal contractility, such as those caused by pelvic floor disorders and current treatment strategies, can be prevented. STATEMENT OF SIGNIFICANCE: Contractile forces of the vagina have been measured by several investigators using uniaxial tensile testing methods. Unlike previous studies, in this study planar-biaxial tests of vaginal specimens were performed while the full-field strains of the vagina, as induced by smooth muscle contraction, were measured. The vagina was found to generate significantly larger contractile strains and forces in the longitudinal direction than in the circumferential direction. Knowledge of the contractile mechanics of the healthy vagina is essential to understand the detrimental effects that pelvic organ prolapse and the use of surgical meshes have on the functionality of smooth muscle in the vagina.

Novel Application of Photogrammetry to Quantify Fascicle Orientations of Female Cadaveric Pelvic Floor Muscles.

Although critical for understanding and simulating pelvic floor muscle function and pathophysiology, the fascicle arrangements of the coccygeus and levator ani remain mostly undetermined. We performed close-range photogrammetry on cadaveric pelvic floor muscles to robustly quantify surface fascicle orientations. The pelvic floor muscles of 5 female cadavers were exposed through anatomic dissections, removed en bloc, and photographed from every required angle. Overlapping images were mapped onto in silico geometries and muscle fascicles were traced manually. Tangent vectors were calculated along each trace; interpolated to define continuous, 3D vector fields; and projected onto axial and sagittal planes to calculate angles with respect to the pubococcygeal line. Contralateral and ipsilateral pelvic floor muscles were compared within each donor (Kuiper's tests) and using mean values from all donors (William-Watsons tests). Contralateral muscles and all but one ipsilateral muscle pair differed significantly within each donor (p < 0.001). When mean values were considered collectively, no contralateral or ipsilateral statistical differences were found but all muscles compared differed by more than 10° on average. Close-range photogrammetry and subsequent analyses robustly quantified surface fascicle orientations of the pelvic floor muscles. The continuous, 3D vector fields provide data necessary for improving simulations of the female pelvic floor muscles.