3D analysis of cystoceles using magnetic resonance imaging assessing midline, paravaginal, and apical defects

Comparison of urethral parameters in females presenting cystoceles with and without stress urinary incontinence based on dynamic magnetic resonance imaging: are they different?

PURPOSE

To compare urethral parameters between cystocele patients with and without stress urinary incontinence (SUI) and explore factors influencing SUI in cystocele patients via dynamic MRI.

METHODS

The two-dimensional parameters evaluated included the paravaginal defects, levator ani muscle defects, urethral length, urethral funnel shape, bladder neck funnel width, bladder neck funnel depth, urethral angle, posterior vesicourethral angle, and anterior bladder protrusion. The three-dimensional parameters included the proximal urethra rotation angle, the distal urethra rotation angle, bladder neck mobility, urethral midpoint mobility, and external urethral meatus mobility. The independent samples t test was used for continuous variables, and the chi-square test was used for categorical variables. Binary logistic regression was used to identify factors independently associated with SUI in cystocele patients.

RESULTS

The baseline parameters were similar between the 2 groups. Cystocele patients with SUI had a significantly higher point Aa (1.63 ± 1.06 cm vs. 0.81 ± 1.51 cm, p = 0.008); more anterior bladder protrusion (33.3% vs. 11.4%, p = 0.017); greater bladder neck mobility (36.38 ± 11.46 mm vs. 28.81 ± 11.72 mm, p = 0.005); mid-urethral mobility (22.94 ± 6.50 mm vs. 19.23 ± 6.65 mm, p = 0.014); and external urethral meatus mobility (22.42 ± 8.16 mm vs. 18.03 ± 8.51 mm, p = 0.022) than did cystocele patients without SUI. The other urethral parameters were similar in the groups (p > 0.05). Binary logistic regression showed that bladder neck mobility was independently associated with SUI in females with cystoceles (odds ratio, 1.06; 95% CI 1.015-1.107; p = 0.009).

CONCLUSION

Cystocele patients with SUI have a higher point Aa, more anterior bladder protrusion, and greater urethral mobility than those without SUI. Bladder neck mobility is independently associated with SUI in females with cystoceles.

REGISTRATION NUMBER

NCT03146195.

Variations in structural support site failure patterns by prolapse size on stress 3D MRI

INTRODUCTION AND HYPOTHESIS

Our objective was to develop a standardized measurement system to evaluate structural support site failures among women with anterior vaginal wall-predominant prolapse according to increasing prolapse size using stress three-dimensional (3D) magnetic resonance imaging (MRI).

METHODS

Ninety-one women with anterior vaginal wall-predominant prolapse and uterus in situ who had undergone research stress 3D MRI were included for analysis. The vaginal wall length and width, apex and paravaginal locations, urogenital hiatus diameter, and prolapse size were measured at maximal Valsalva on MRI. Subject measurements were compared to established measurements in 30 normal controls without prolapse using a standardized z-score measurement system. A z-score greater than 1.28, or the 90th percentile in controls, was considered abnormal. The frequency and severity of structural support site failure was analyzed based on tertiles of prolapse size.

RESULTS

Substantial variability in support site failure pattern and severity was identified, even between women with the same stage and similar size prolapse. Overall, the most common failed support sites were straining hiatal diameter (91%) and paravaginal location (92%), followed by apical location (82%). Impairment severity z-score was highest for hiatal diameter (3.56) and lowest for vaginal width (1.40). An increase in impairment severity z-score was observed with increasing prolapse size among all support sites across all three prolapse size tertiles (p < 0.01 for all).

CONCLUSIONS

We identified substantial variation in support site failure patterns among women with different degrees of anterior vaginal wall prolapse using a novel standardized framework that quantifies the number, severity, and location of structural support site failures.

Vaginal delivery effects on 3D morphology of the bladder, urethra, and vagina: a pilot study comparing women with different numbers of deliveries

PURPOSE

To explore 3D morphological changes of the bladder, urethra, and vagina following different numbers of vaginal deliveries.

METHODS

Sampled patients had undergone magnetic resonance imaging for gynecological diseases in Nanfang Hospital. A total of 167 patients who met the study inclusion and exclusion criteria were enrolled and divided into four groups. Mimics and UG software packages were used for reconstructions and measurements, and data were compared with one-way analyses of variance.

RESULTS

A total of 167 3D models were constructed, and eight parameters related to the bladder and urethra were measured (5 angles, 2 lengths, and 1 thickness). No statistically significant differences were found between subgroups, although mean plot figures of urethra pubic and α angles showed trends to increase with more deliveries, and the opposite trend was seen for the urethra tilt angle. There were no obvious trends between other parameters and delivery number. There were seven vaginal parameters (6 lengths and 1 shape). Mid-urethral and vaginal gap measurements tended to become wider as delivery number increased, and the opposite was seen for the distal gap. Mid-vaginal 2D cross-sectional shape and the proportion of shallow concave types also tended to significantly increase with more deliveries, especially after the third birth.

CONCLUSION

As the number of deliveries through the vagina increases, the lateral support function of this organ and the urethra become relatively weaker. These fine anatomical changes are related to delivery numbers and become most obvious after the third birth.

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.

Surgical anatomy of the mid-vagina

AIM

The mid-vagina (MV) represents Level II of the vagina. The surgical anatomy of the MV has not been recently subject to a comprehensive examination and description. MV surgery involving anterior and posterior colporrhaphy represents a key part of surgery for a majority of pelvic organ prolapse (POP).

METHODS

Literature review and surgical observations of many aspects of the MV were performed including MV length and width; MV shape; immediate relationships; histological analysis; anterior and posterior MV prolapse assessment and anterior MV surgical aspects. Unpublished pre- and postoperative quantitative data on 300 women undergoing posterior vaginal compartment repairs are presented.

RESULTS

The MV runs from the lower limit of the vaginal vault (VV) to the hymen. Its length is a mean of 5 cm. Its shape in section overall is a compressed rectangle. Its longitudinal shape is created by its anterior and posterior walls being inverse trapezoid in shape. Histology comprises three layers: (i) mucosa; (ii) muscularis; (iii) adventitia. MV prolapse staging uses pelvic organ prolapse quantification (POP-Q). Anterior MV prolapse can be quantitatively assessed using POP-Q while posterior MV prolapse can be assessed with POP-Q or PR-Q. Around 50% of both cystocele and rectocele are due to VV defects. POP will increase anterior MV width and length. Native tissue anterior colporrhaphy is the current conventional repair with mesh disadvantages outweighing advantages. Posteriorly, Level II (MV) defects are far smaller (mean 1.3 cm) than Level I (mean 6.0 cm) and Level III (mean 2.9 cm).

CONCLUSION

An understanding of the surgical anatomy of the MV can assist anterior and posterior colporrhaphy. In particular, if VV support is employed, the Level II component of a posterior repair should be relatively small.

Multilevel musculo-fascial defect magnetic resonance study of female pelvic floor: retrospective case control study in women with pelvic floor dysfunction after the first vaginal delivery

INTRODUCTION

Magnetic resonance imaging (MRI) provides a detailed display of the pelvic floor structures responsible for normal pelvic floor anatomy. The aim of the study is to assess the appearance of musculo-fascial defects in women with pelvic floor dysfunction following first vaginal delivery.

MATERIAL AND METHODS

Analysis of axial T3 (Tesla 3) MRI scans from a case control study of symptomatic (n = 149) and asymptomatic (n = 60) women after first vaginal delivery. Presence and severity of pelvic organ support and attachment system defects in three axial pelvic planes were assessed.

RESULTS

In the symptomatic group, major muscular defects were found in 67.1% (for pubovisceral muscle complex) and 87.9% (for iliococcygeal muscle). Only 6.7% of major pubovisceral and 35.0% of major iliococcygeal defects were identified in the controls (p = 0.000). Prolapse patients had an odds ratio (OR) of 22.1 (95% CI 8.94-54.67) to have major pubovisceral muscle complex defect and OR of 4.9 (95% CI 1.51-15.71) to have major iliococcygeal muscle defect. Fascial defects were found in 60.4% and 83.2% the symptomatic group, respectively. Those with prolapse had an OR of 29.1 (95% CI 9.77-86.31) to have facial defect at the level of pubovisceral muscle complex and an OR of 16.9 (95% CI 7.62-37.69) to have fascial defect at the level of iliococcygeal muscle. Uterosacral ligaments detachment was associated with prolapse with an OR of 10.1 (95% CI 4.01-25.29). For the model based on combination on all MRI markers, the area under the receiver operating characteristic curve is 0.921.

CONCLUSIONS

This study provides comprehensive data about first vaginal delivery-induced changes in the levator ani muscle and endopelvic fascial attachment system. These changes are seen also in asymptomatic controls, but they are significantly less expressed.

ACR Appropriateness Criteria® Pelvic Floor Dysfunction in Females

Pelvic floor disorders including pelvic organ prolapse (POP), urinary dysfunction, defecatory dysfunction, and complications after pelvic floor surgery are relatively common in the female population. Imaging tests are obtained when the initial clinical evaluation is thought to be incomplete or inconclusive or demonstrates findings that are discordant with patients' symptoms. An integrated imaging approach is optimal to evaluate the complex anatomy and dynamic functionality of the pelvic floor. Fluoroscopic cystocolpoproctography (CCP) and MR defecography are considered the initial imaging tests of choice for evaluation of POP. Fluoroscopic voiding cystourethrography is considered the initial imaging test for patients with urinary dysfunction. Fluoroscopic CCP and MR defecography are considered the initial imaging test for patients with defecatory dysfunction, whereas ultrasound pelvis transrectal is a complementary test in patients requiring evaluation for anal sphincter defects. MRI pelvis without and with intravenous contrast, MRI pelvis with dynamic maneuvers, and MR defecography are considered the initial imaging tests in patients with suspected complications of prior pelvic floor surgical repair. Transperineal ultrasound is emerging as an important imaging tool, in particular for screening of pelvic floor dysfunction and for evaluation of midurethral slings, vaginal mesh, and complications related to prior pelvic floor surgical repair. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Three-dimensional self super-resolution for pelvic floor MRI using a convolutional neural network with multi-orientation data training

PURPOSE

High-resolution pelvic magnetic resonance (MR) imaging is important for the high-resolution and high-precision evaluation of pelvic floor disorders (PFDs), but the data acquisition time is long. Because high-resolution three-dimensional (3D) MR data of the pelvic floor are difficult to obtain, MR images are usually obtained in three orthogonal planes: axial, sagittal, and coronal. The in-plane resolution of the MR data in each plane is high, but the through-plane resolution is low. Thus, we aimed to achieve 3D super-resolution using a convolutional neural network (CNN) approach to capture the intrinsic similarity of low-resolution 3D MR data from three orientations.

METHODS

We used a two-dimensional (2D) super-resolution CNN model to solve the 3D super-resolution problem. The residual-in-residual dense block network (RRDBNet) was used as our CNN backbone. For a given set of low through-plane resolution pelvic floor MR data in the axial or coronal or sagittal scan plane, we applied the RRDBNet sequentially to perform super-resolution on its two projected low-resolution views. Three datasets were used in the experiments, including two private datasets and one public dataset. In the first dataset (dataset 1), MR data acquired from 34 subjects in three planes were used to train our super-resolution model, and low-resolution MR data from nine subjects were used for testing. The second dataset (dataset 2) included a sequence of relatively high-resolution MR data acquired in the coronal plane. The public MR dataset (dataset 3) was used to demonstrate the generalization ability of our model. To show the effectiveness of RRDBNet, we used datasets 1 and 2 to compare RRDBNet with interpolation and enhanced deep super-resolution (EDSR) methods in terms of peak signal-to-noise ratio (PSNR) and structural similarity (SSIM) index. As 3D MR data from one view have two projected low-resolution views, different super-resolution orders were compared in terms of PSNR and SSIM. Finally, to demonstrate the impact of super-resolution on the image analysis task, we used datasets 2 and 3 to compare the performance of our method with interpolation on the 3D geometric model reconstruction of the urinary bladder.

RESULTS

A CNN-based method was used to learn the intrinsic similarity among MR acquisitions from different scan planes. Through-plane super-resolution for pelvic MR images was achieved without using high-resolution 3D data, which is useful for the analysis of PFDs.

Improving of long-term follow-up after cystocele repair

INTRODUCTION

The anterior vaginal wall is the most common site of repair compared with apex and posterior vaginal wall, and is also the site with the highest recurrence rate after surgery. The aim of this study was to evaluate the anatomical location of apex in patients with cystocele staged 2-3 (POP-Q), to correct all anatomical defects and to improve cystocele repair results.

MATERIALS AND METHODS

This was a single-center prospective study of women with cystocele of stage 2-3 with and without apical prolapse who underwent combined surgical treatment. The authors performed combined surgical procedures in women with apical prolapse, including pectopexy. Clinical and anatomical follow-ups were carried out at least in 12 months.

RESULTS

All patients revealed good to excellent results, with a high rate of satisfaction. There were no significant differences in recurrence among women with and without apical prolapse. Of the 22 women after pectopexy, the only one had apical prolapse of grade 1. The median cystocele recurrence rate was 3.8% in group without apical prolapse (grade 1), and 4.5% (grade 1) in pectopexy group. Sexual matters, incontinence score and QoL were significantly improved in both groups. The main reason for cystocele low recurrence rate is defect-oriented multicompartment strategy in all cases including patients with and without apical defect.

CONCLUSION

Pectopexy can be a good choice for prolapse surgery, including the positive effect in cases of lateral anterior wall defect. Using this strategy, it becomes possible to perform native tissue vaginal repair with encouraged long-term follow-ups.

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.

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.

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.

Practice Patterns Regarding Apical Support Procedures at Time of Hysterectomy for Pelvic Organ Prolapse

OBJECTIVES

We sought to understand practice patterns of non-female pelvic medicine and reconstructive surgery (FPMRS) clinicians regarding concurrent apical support procedures during hysterectomies when primarily performed for the treatment of pelvic organ prolapse. We also sought to describe differences between those receiving and not receiving apical support.

METHODS

This retrospective study analyzed medical records of individuals undergoing hysterectomy for the primary indication of pelvic organ prolapse between 2012 and 2017 at all locations within the TriHealth system. Surgeries performed by board-certified FPMRS physicians were excluded. Comparisons were drawn between those who did and did not receive apical support.

RESULTS

A total of 236 charts met the inclusion criteria. Of these, 66 (28%) received concurrent apical suspension, and 94 (39.8%) underwent no reconstructive procedures. The annual proportion of those receiving apical suspension did not differ over the course of the study period. On average, the addition of apical support added 39.9 minutes (P < 0.001) to the length of surgery. There was, however, no difference noted in estimated blood loss. Risk factors for recurrent prolapse including chronic constipation, pulmonary disease, and connective tissue disorders were similar between groups.

CONCLUSION

When excluding FPMRS surgeons, data from our institution showed that most patients undergoing hysterectomy for prolapse did not receive concurrent apical support. This suggests areas of potential improvement for adopting into clinical practice the new American College of Obstetricians and Gynecologists recommendations regarding the treatment of prolapse. Furthermore, this may represent an important opportunity for peer outreach and education by FPMRS surgeons.

Pelvic Organ Prolapse: ACOG Practice Bulletin, Number 214

Pelvic organ prolapse (POP) is a common, benign condition in women. For many women it can cause vaginal bulge and pressure, voiding dysfunction, defecatory dysfunction, and sexual dysfunction, which may adversely affect quality of life. Women in the United States have a 13% lifetime risk of undergoing surgery for POP (). Although POP can occur in younger women, the peak incidence of POP symptoms is in women aged 70-79 years (). Given the aging population in the United States, it is anticipated that by 2050 the number of women experiencing POP will increase by approximately 50% (). The purpose of this joint document of the American College of Obstetricians and Gynecologists and the American Urogynecologic Society is to review information on the current understanding of POP in women and to outline guidelines for diagnosis and management that are consistent with the best available scientific evidence.

Development of anatomically based customizable three-dimensional finite-element model of pelvic floor support system: POP-SIM1.0

To develop an anatomically based customizable finite-element (FE) model of the pelvic floor support system to simulate pelvic organ prolapse (POP): POP-SIM1.0. This new simulation platform allows for the construction of an array of models that objectively represent the key anatomical and functional variation in women with and without prolapse to test pathomechanism hypotheses of the prolapse formation. POP-SIM1.0 consists of anatomically based FE models and a suite of Python-based tools developed to rapidly construct FE models by customizing the base model with desired structural parameters. Each model consists of anatomical structures from three support subsystems which can be customized based on magnetic resonance image measurements in women with and without prolapse. The customizable structural parameters include presence of levator ani (LA) avulsion, hiatus size, anterior vaginal wall dimension, attachment fascia length and apical location in addition to the tissue material properties and intra-abdominal pressure loading. After customization, the FE model was loaded with increasing intra-abdominal pressure (0-100 cmH2O) and solved using ABAQUS explicit solver. We were able to rapidly construct anatomically based FE models with specific structural geometry which reflects the morphology changes often observed in women with prolapse. At maximum loading, simulated structural deformations have similar anatomical characteristics to those observed during clinical exams and stress magnetic resonance images. Simulation results showed the presence of LA muscle avulsion negatively impacts the pelvic floor support. The normal model with intact muscle had the smallest exposed vaginal length of 11 mm, while the bilateral avulsion produced the largest exposed vaginal length at 24 mm. The unilateral avulsion model had an exposed vaginal length of 18 mm and also demonstrated a tipped perineal body similar to that seen in clinical observation. Increasing the hiatus size, vaginal wall length and fascia length also resulted in worse pelvic floor support, increasing the exposed vaginal length from 18 mm in the base model to 33 mm, 54 mm and 23.5 mm, respectively. The developed POP-SIM1.0 can simulate the anatomical structure changes often observed in women with prolapse. Preliminary results showed that the presence of LA avulsion, enlarged hiatus, longer vaginal wall and fascia length can result in larger prolapse at simulated maximum Valsalva.

Novel Incision-free Device for Transvaginal Apical Pelvic Organ Prolapse Repair

STUDY OBJECTIVE

The purpose of this study was to present the feasibility and potential clinical advantages of Apyx (Escala Medical, Israel), a minimally invasive incision-free anchoring device, for apical prolapse repair.

DESIGN

An experimental prospective animal and cadaver study.

SETTING

Animal facility and a cadaver laboratory of a tertiary care teaching hospital.

PATIENTS

Included in this study were 7 ovine models, 2 porcine specimens, and 3 fresh unembalmed female human cadavers.

INTERVENTIONS

The Apyx device for sacrospinous ligament (SSL) suspension was tested on ovine and porcine models. The pullout force needed to detach the Apyx anchor from the SSL was measured. Safety, reliability, and feasibility of this new incision-free procedure were also tested on an ovine model and human cadavers. The precision in deployment of the Apyx device to the SSL was tested via palpation by the surgeon, tissue dissection, and x-ray imaging. The efficacy was tested both by pullout forces and histologic analysis of the vaginal attachment to the SSL.

MEASUREMENTS AND MAIN RESULTS

Forty-two anchors were inserted into the SSLs on ovine and porcine models and on cadaver SSLs. No abnormalities or malfunctions were noted in the functional performance of the anchors or the retrieval device. Mean pullout force for the ovine animal model was 38.64 ± 2.80 N. Pullout force in the porcine model was found to be in correlation with the values observed in the ovine model. None of the measured forces was below 20 N. Accuracy and safety tests showed good consistency when deploying the Apyx device to the SSL with no damage to surrounding organs in the ovine or the human cadaver model. Histology demonstrated biologic adhesion characterized by a gross assessment of a newly formed, firm fibrotic tissue 12 weeks after anchor deployment.

CONCLUSION

The Apyx anchoring system, a novel incision-free minimally invasive prolapse repair device, demonstrated an anatomically feasible, easy-to-use procedure for suspending the vaginal apex to the SSLs. Its clinical safety, efficacy, and impact on patient symptoms and quality of life should be further studied.

Recommended standardized terminology of the anterior female pelvis based on a structured medical literature review

BACKGROUND

The use of imprecise and inaccurate terms leads to confusion amongst anatomists and medical professionals.

OBJECTIVE

We sought to create recommended standardized terminology to describe anatomic structures of the anterior female pelvis based on a structured review of published literature and selected text books.

STUDY DESIGN

We searched MEDLINE from its inception until May 2, 2016, using 11 medical subject heading terms to identify studies reporting on anterior female pelvic anatomy; any study type published in English was accepted. Nine textbooks were also included. We screened 12,264 abstracts, identifying 200 eligible studies along with 13 textbook chapters from which we extracted all pertinent anatomic terms.

RESULTS

In all, 67 unique structures in the anterior female pelvis were identified. A total of 59 of these have been previously recognized with accepted terms in Terminologia Anatomica, the international standard on anatomical terminology. We also identified and propose the adoption of 4 anatomic regional terms (lateral vaginal wall, pelvic sidewall, pelvic bones, and anterior compartment), and 2 structural terms not included in Terminologia Anatomica (vaginal sulcus and levator hiatus). In addition, we identified 2 controversial terms (pubourethral ligament and Grafenberg spot) that require additional research and consensus from the greater medical and scientific community prior to adoption or rejection of these terms.

CONCLUSION

We propose standardized terminology that should be used when discussing anatomic structures in the anterior female pelvis to help improve communication among researchers, clinicians, and surgeons.

Structural, functional, and symptomatic differences between women with rectocele versus cystocele and normal support

BACKGROUND

Prolapse of the anterior and posterior vaginal walls has been generally associated with apical descent and levator ani muscle defects. However, the relative contributions of these factors to the pathophysiology of descent in the different vaginal compartments is not well understood. Furthermore, symptoms uniquely associated with prolapse in these compartments have not been well characterized.

OBJECTIVES

The objectives of the study were to compare the associations between the following: (1) apical support, (2) levator ani muscles, and (3) pelvic floor symptoms in women with posterior-predominant prolapse, anterior-predominant prolapse, and normal support.

STUDY DESIGN

This is a cross-sectional study with 2 case arms: 60 women with posterior prolapse, 90 with anterior prolapse, and a referent control arm with 103 asymptomatic subjects with normal support, determined from pelvic organ prolapse quantification examinations. Levator muscle defects were graded from magnetic resonance imaging. Vaginal closure forces above resting were measured with an instrumented speculum during maximal contraction. Pelvic floor symptoms were measured via the Pelvic Floor Distress Inventory-Short Form.

RESULTS

Mean point C location in controls was -6.9 cm [1.5] (mean [standard deviation]); and was higher in posterior prolapse (-4.7 cm [2.7], 2.2 cm below controls) than the anterior prolapse group (-1.2 cm [4.1]; 5.6 cm below controls, P < .001 for all comparisons). Normal-appearing muscles (ie, muscle without a visible defect) occurred at similar frequencies in posterior prolapse (45%) and controls (51%, P = .43) but less often in anterior prolapse (28%, P ≤ .03 for pairwise comparisons). Major levator ani defects occurred at similar rates in women with posterior (33%) and anterior prolapse (42%, P = .27) but less often in controls (16%, P ≤ .012 for both pairwise comparisons). Similarly, there were significant differences in generated vaginal closure forces across the 3 groups, with the prolapse groups generating weaker closure forces than the control group (P = .004), but the differences between the 2 prolapse groups were not significant after controlling for prolapse size (P = .43). Pelvic floor symptoms were more severe for the posterior (mean Pelvic Floor Distress Inventory score, 129) and anterior prolapse groups (score, 128) than the controls (score, 40.2, P < .001 for both comparisons); the difference between the 2 prolapse groups was not significant (P = .83).

CONCLUSION

Posterior-predominant prolapse involves an almost 3-fold less apical descent below normal than anterior-predominant vaginal prolapse. Levator ani defects and muscle impairment also have a lower impact. Pelvic floor symptoms reflect the presence and size of prolapse more than the predominant lax vaginal compartment.

Modern Theories of Pelvic Floor Support : A Topical Review of Modern Studies on Structural and Functional Pelvic Floor Support from Medical Imaging, Computational Modeling, and Electromyographic Perspectives

PURPOSE OF REVIEW

Weakened pelvic floor support is believed to be the main cause of various pelvic floor disorders. Modern theories of pelvic floor support stress on the structural and functional integrity of multiple structures and their interplay to maintain normal pelvic floor functions. Connective tissues provide passive pelvic floor support while pelvic floor muscles provide active support through voluntary contraction. Advanced modern medical technologies allow us to comprehensively and thoroughly evaluate the interaction of supporting structures and assess both active and passive support functions. The pathophysiology of various pelvic floor disorders associated with pelvic floor weakness is now under scrutiny from the combination of (1) morphological, (2) dynamic (through computational modeling), and (3) neurophysiological perspectives. This topical review aims to update newly emerged studies assessing pelvic floor support function among these three categories.

RECENT FINDINGS

A literature search was performed with emphasis on (1) medical imaging studies that assess pelvic floor muscle architecture, (2) subject-specific computational modeling studies that address new topics such as modeling muscle contractions, and (3) pelvic floor neurophysiology studies that report novel devices or findings such as high-density surface electromyography techniques. We found that recent computational modeling studies are featured with more realistic soft tissue constitutive models (e.g., active muscle contraction) as well as an increasing interest in simulating surgical interventions (e.g., artificial sphincter). Diffusion tensor imaging provides a useful non-invasive tool to characterize pelvic floor muscles at the microstructural level, which can be potentially used to improve the accuracy of the simulation of muscle contraction. Studies using high-density surface electromyography anal and vaginal probes on large patient cohorts have been recently reported. Influences of vaginal delivery on the distribution of innervation zones of pelvic floor muscles are clarified, providing useful guidance for a better protection of women during delivery. We are now in a period of transition to advanced diagnostic and predictive pelvic floor medicine. Our findings highlight the application of diffusion tensor imaging, computational models with consideration of active pelvic floor muscle contraction, high-density surface electromyography, and their potential integration, as tools to push the boundary of our knowledge in pelvic floor support and better shape current clinical practice.

What's new in the functional anatomy of pelvic organ prolapse?

PURPOSE OF REVIEW

Provide an evidence-based review of pelvic floor functional anatomy related to pelvic organ prolapse.

RECENT FINDINGS

Pelvic organ support depends on interactions between the levator ani muscle and pelvic connective tissues. Muscle failure exposes the vaginal wall to a pressure differential producing abnormal tension on the attachments of the pelvic organs to the pelvic sidewall. Birth-induced injury to the pubococcygeal portion of the levator ani muscle is seen in 55% of women with prolapse and 16% of women with normal support. Failure of the lateral connective tissue attachments between the uterus and vagina to the pelvic wall (cardinal, uterosacral, and paravaginal) are strongly related with prolapse (effect sizes ∼2.5) and are also highly correlated with one another (r ∼ 0.85). Small differences exist with prolapse in factors involving the vaginal wall length and width (effect sizes ∼1). The primary difference in ligament properties between women with and without prolapse is found in ligament length. Only minor differences in ligament stiffness are seen.

SUMMARY

Pelvic organ prolapse occurs because of injury to the levator ani muscles and failure of the lateral connections between the pelvic organs to the pelvic sidewall. Abnormalities of the vaginal wall fascial tissues may play a minor role.

Natural history of pelvic organ prolapse in symptomatic patients actively seeking treatment

INTRODUCTION AND HYPOTHESIS

At our institution many symptomatic patients must wait months or years for surgery. Our aim was to determine the rates of clinically significant pelvic organ prolapse (POP) progression and identify risk factors associated with POP progression.

METHODS

Data from a prospectively maintained database of POP patients evaluated between 2008 and 2013 were analyzed. Women with symptomatic POP and two or more POP-Q examinations prior to surgery were included. POP progression was defined as having any of the POP-Q points Aa, Ba, C, D, Ap or Bp above the hymen at the baseline examination and at or below the hymen at the follow-up examination. Multivariable logistic analysis was preformed and the results are presented as odds ratios (OR) with 95% confidence intervals (CI).

RESULTS

Of consecutive patients evaluated between July 2008 and June 2013, 388 met the inclusion criteria and were included. The median time between the POP-Q examinations was 9.9 months (IQR 7.8 to 13.8 months). The POP progression rate was 29.1% (95% CI 24.6-33.6%). Predictors of progression included age (OR 1.7, 95% CI 1.01-2.87) and the baseline status of points Ba, C, Bp and gH (OR 1.91, 95% CI 1.01-3.62; OR 0.53, 95% CI 0.3-0.94; OR 0.54, 95% CI 0.32-0.93; OR 2.15, 95% CI 1.13-4.1; respectively). POP-Q point correlations showed that anterior and posterior compartment points evolve with apical compartment points and gH evolves with both the anterior compartment and the apex.

CONCLUSIONS

Up to 29.1% of symptomatic patients with POP showed clinically significant progression over a median follow-up of 9.9 months. The likelihood of progression was not significantly associated with time. Those ≥60 years of age as well as those with point Ba ≥4 cm or gH ≥5 cm at baseline were at increased risk of POP progression.

Structural Failure Sites in Anterior Vaginal Wall Prolapse: Identification of a Collinear Triad

OBJECTIVE

To test the null hypothesis that six factors representing potential fascial and muscular failure sites contribute equally to the presence and size of a cystocele: two vaginal attachment factors (apical support and paravaginal defects), two vaginal wall factors (vaginal length and width), and two levator ani factors (hiatus size and levator ani defects).

METHODS

Thirty women with anterior-predominant prolapse (women in a case group) and 30 women in a control group underwent three-dimensional stress magnetic resonance imaging. The location of the anterior vaginal wall at maximal Valsalva was identified with the modified Pelvic Inclination Coordinate System and the six factors measured. Analysis included repeated-measure analysis of variance, logistic regression, and stepwise linear regression.

RESULTS

We identified a collinear triad consisting of apical location, paravaginal location, and hiatus size that were not only the strongest predictors of cystocele size, but were also highly correlated with one another (r=0.84-0.89, P<.001) for the presence and size of the prolapse. Together they explain up to 83% of the variation in cystocele size. Among the less significant vaginal factors, vaginal length explained 19% of the variation in cystocele size, but no significant difference in vaginal width existed. Women in the case group were more likely to have abnormalities in collinear triad factors (up to 80%) than vaginal wall factors (up to 23.3%). Combining the strongest collinear triad with the vaginal factors, the model explained 92.5% of the variation in cystocele size.

CONCLUSION

Apical location, paravaginal location, and hiatus size are highly correlated and are strong predictors of cystocele presence and size.

A biofidelic computational model of the female pelvic system to understand effect of bladder fill and progressive vaginal tissue stiffening due to prolapse on anterior vaginal wall

Treatment of anterior vaginal prolapse (AVP), suffered by over 500,000 women in the USA, is a challenge in urogynecology because of the poorly understood mechanics of AVP. Recently, computational modeling combined with finite element method has been used to model AVP through the study of pelvic floor muscle and connective tissue impairments on the anterior vaginal wall (AVW). Also, the effects of pelvic organ displacements on the AVW were studied numerically. In our current work, an MRI-based full-scale biofidelic computational model of the female pelvic system composed of the urinary bladder, vaginal canal, and the uterus was developed, and a novel finite element method framework was employed to simulate vaginal tissue stiffening and also bladder filling due to expansion for the first time. A mesh convergence study was conducted to choose a computationally efficient mesh, and a non-linear hyperelastic Yeoh's material model was adopted for the study. The AVW displacements, mechanical stresses, and strains were estimated at varying degrees of bladder fills and vaginal tissue stiffening. Both bladder filling and vaginal stiffening were found to increase the stress concentration on the AVW with varying trends, which have been discussed in detail in the paper. To our knowledge, this study is the first to estimate the individual and combined effects of bladder filling and vaginal tissue stiffening due to prolapse on the AVW. Copyright © 2016 John Wiley & Sons, Ltd.

Paravaginal defect: anatomy, clinical findings, and imaging

INTRODUCTION AND HYPOTHESIS

The paravaginal defect has been a topic of active discussion concerning what it is, how to diagnose it, its role in anterior vaginal wall prolapse, and if and how to repair it. The aim of this article was to review the existing literature on paravaginal defect and discuss its role in the anterior vaginal wall support system, with an emphasis on anatomy and imaging.

METHODS

Articles related to paravaginal defects were identified through a PubMed search ending 1 July 2015.

RESULTS

Support of the anterior vaginal wall is a complex system involving levator ani muscle, arcus tendineus fascia pelvis (ATFP), pubocervical fascia, and uterosacral/cardinal ligaments. Studies conclude that physical examination is inconsistent in detecting paravaginal defects. Ultrasound (US) and magnetic resonance imaging (MRI) have been used to describe patterns in the appearance of the vagina and bladder when a paravaginal defect is suspected. Different terms have been used (e.g., sagging of bladder base, loss of tenting), which all represent changes in pelvic floor support but that could be due to both paravaginal and levator ani defects.

CONCLUSION

Paravaginal support plays a role in supporting the anterior vaginal wall, but we still do not know the degree to which it contributes to the development of prolapse. Both MRI and US are useful in the diagnosis of paravaginal defects, but further studies are needed to evaluate their use.

Cystocele and functional anatomy of the pelvic floor: review and update of the various theories

INTRODUCTION AND HYPOTHESIS

We updated anatomic theories of pelvic organ support to determine pathophysiology in various forms of cystocele.

METHODS

PubMed/MEDLINE, ScienceDirect, Cochrane Library, and Web of Science databases were searched using the terms pelvic floor, cystocele, anatomy, connective tissue, endopelvic fascia, and pelvic mobility. We retrieved 612 articles, of which 61 matched our topic and thus were selected. Anatomic structures of bladder support and their roles in cystocele onset were determined on the international anatomic classification; the various anatomic theories of pelvic organ support were reviewed and a synthesis was made of theories of cystocele pathophysiology.

RESULTS

Anterior vaginal support structures comprise pubocervical fascia, tendinous arcs, endopelvic fascia, and levator ani muscle. DeLancey's theory was based on anatomic models and, later, magnetic resonance imaging (MRI), establishing a three-level anatomopathologic definition of prolapse. Petros's integral theory demonstrated interdependence between pelvic organ support systems, linking ligament-fascia lesions, and clinical expression. Apical cystocele is induced by failure of the pubocervical fascia and insertion of its cervical ring; lower cystocele is induced by pubocervical fascia (medial cystocele) or endopelvic fascia failure at its arcus tendineus fasciae pelvis attachment (lateral cystocele).

CONCLUSIONS

Improved anatomic knowledge of vaginal wall support mechanisms will improve understanding of cystocele pathophysiology, diagnosis of the various types, and surgical techniques. The two most relevant theories, DeLancey's and Petros's, are complementary, enriching knowledge of pelvic functional anatomy, but differ in mechanism. Three-dimensional digital models could integrate and assess the mechanical properties of each anatomic structure.

A multi-compartment 3-D finite element model of rectocele and its interaction with cystocele

We developed a subject-specific 3-D finite element model to understand the mechanics underlying formation of female pelvic organ prolapse, specifically a rectocele and its interaction with a cystocele. The model was created from MRI 3-D geometry of a healthy 45 year-old multiparous woman. It included anterior and posterior vaginal walls, levator ani muscle, cardinal and uterosacral ligaments, anterior and posterior arcus tendineus fascia pelvis, arcus tendineus levator ani, perineal body, perineal membrane and anal sphincter. Material properties were mostly from the literature. Tissue impairment was modeled as decreased tissue stiffness based on previous clinical studies. Model equations were solved using Abaqus v 6.11. The sensitivity of anterior and posterior vaginal wall geometry was calculated for different combinations tissue impairments under increasing intraabdominal pressure. Prolapse size was reported as pelvic organ prolapse quantification system (POP-Q) point at point Bp for rectocele and point Ba for cystocele. Results show that a rectocele resulted from impairments of the levator ani and posterior compartment support. For 20% levator and 85% posterior support impairments, simulated rectocele size (at POP-Q point: Bp) increased 0.29 mm/cm H2O without apical impairment and 0.36 mm/cm H2O with 60% apical impairment, as intraabdominal pressures increased from 0 to 150 cm H2O. Apical support impairment could result in the development of either a cystocele or rectocele. Simulated repair of posterior compartment support decreased rectocele but increased a preexisting cystocele. We conclude that development of rectocele and cystocele depend on the presence of anterior, posterior, levator and/or or apical support impairments, as well as the interaction of the prolapse with the opposing compartment.

Three-dimensional modeling of the pelvic floor support systems of subjects with and without pelvic organ prolapse

The purpose of this study was to develop three-dimensional finite element models of the whole pelvic support systems of subjects with and without pelvic organ prolapse (POP) that can be used to simulate anterior and posterior wall prolapses. Magnetic resonance imaging was performed in one healthy female volunteer (55 years old, para 2) and one patient (56 years old, para 1) with anterior vaginal wall prolapse. Contours of the pelvic structures were traced by a trained gynecologist. Smoothing of the models was conducted and attachments among structures were established. Finite element models of the pelvic support system with anatomic details were established for both the healthy subject and the POP patient. The models include the uterus, vagina with cavity, cardinal and uterosacral ligaments, levator ani muscle, rectum, bladder, perineal body, pelvis, obturator internus, and coccygeal muscle. Major improvements were provided in the modeling of the supporting ligaments and the vagina with high anatomic precision. These anatomically accurate models can be expected to allow study of the mechanism of POP in more realistic physiological conditions. The resulting knowledge may provide theoretical help for clinical prevention and treatment of POP.

ACR Appropriateness Criteria pelvic floor dysfunction

Pelvic floor dysfunction is a common and potentially complex condition. Imaging can complement physical examination by revealing clinically occult abnormalities and clarifying the nature of the pelvic floor defects present. Imaging can add value in preoperative management for patients with a complex clinical presentation, and in postoperative management of patients suspected to have recurrent pelvic floor dysfunction or a surgical complication. Imaging findings are only clinically relevant if the patient is symptomatic. Several imaging modalities have a potential role in evaluating patients; the choice of modality depends on the patient's symptoms, the clinical information desired, and the usefulness of the test. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions; they are reviewed every 3 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals, and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Anatomical Position of Four Different Transobturator Mesh Implants for Female Anterior Prolapse Repair

Purpose: Polypropylene mesh implants are frequently used for pelvic floor reconstruction in women. Yet they vary in size and fixation. The purpose of this study is to compare four mesh products with regard to their anatomical positioning and functionality within the pelvic floor, to determine whether each mesh fits equally well in a female cadaver. Methods: One female pelvis was dissected, opening the retropubic space exposing the endopelvic fascia and demonstrating the arcus tendineus fasciae pelvis (ATFP). Anatomical parameters were measured before and after implanting four meshes via the transobturator approach. Results: The anterior fixation of the ATFP was found to be 5 mm lateral to the symphysis in this cadaver. The endopelvic fascia covered 54.6 cm². The obturator nerve was located 35 mm from the white line. The distance of the proximal and lateral points of mesh fixation from the ischial spine or ATFP varied from 0 to 25 mm. The meshes varied in size and anatomical positioning. Conclusion: These observations demonstrate the necessity of developing optimally sized meshes and appropriate introducer techniques that can provide sufficient vaginal support. Surgeons, furthermore, need profound knowledge of anatomy, the patient's pelvic floor defect and the meshes available on the market.

The length of anterior vaginal wall exposed to external pressure on maximal straining MRI: relationship to urogenital hiatus diameter, and apical and bladder location

INTRODUCTION AND HYPOTHESIS

In cystoceles, the distal anterior vaginal wall (AVW) bulges out through the introitus and is no longer in contact with the posterior vaginal wall or perineal body, exposing the pressure differential between intra-abdominal pressure and atmospheric pressure. The goal of this study is to quantify the length of the exposed vaginal wall length and to investigate its relationship with other factors associated with the AVW support, such as most dependent bladder location, apical location, and hiatus diameter, demonstrating its key role in cystocele formation.

METHODS

Fifty women were selected to represent a full spectrum of AVW support. Each underwent supine, dynamic MR imaging. Most dependent bladder location and apical location were measured relative to the average normal position on the mid-sagittal plane using the Pelvic Inclination Correction System . The length of the exposed AVW and the hiatus diameter were measured as well. The relationship between exposed AVW and most dependent bladder location, apical location, and hiatus diameter were examined.

RESULTS

A bilinear relationship has been observed between exposed vaginal wall length and most dependent bladder location (R(2) = 0.91, P < 0.001). When the bladder descents up to the inflection point (about 4.4 cm away from its normal position), there is little change in the exposed AVW length. With further descent, the exposed vaginal wall length increases significantly, with a 2 cm increase in exposed AVW length for every additional 1 cm of drop bladder location. A similar but weaker bilinear relationship exists between exposed AVW and apical location. Exposed vaginal wall length is also highly correlated with hiatus diameter (R(2) = 0.85, P < 0.001).

CONCLUSION

A bilinear relationship exists between exposed vaginal wall length and most dependent bladder location and apical location. It is when the bladder descent is beyond the inflection point that exposed vaginal wall length increases significantly.

Relationship between intra-abdominal pressure and vaginal wall movements during Valsalva in women with and without pelvic organ prolapse: technique development and early observations

OBJECTIVES

To develop and test a method for measuring the relationship between the rise in intra-abdominal pressure and sagittal plane movements of the anterior and posterior vaginal walls during Valsalva in a pilot sample of women with and without prolapse.

METHODS

Mid-sagittal MRI images were obtained during Valsalva while changes in intra-abdominal pressure were measured via a bladder catheter in 5 women with cystocele, 5 women with rectocele, and 5 controls. The regional compliance of the anterior and posterior vagina wall support systems were estimated from the ratio of displacement (mm) of equidistant points along the anterior and posterior vaginal walls to intra-abdominal pressure rise (mmHg).

RESULTS

The compliance of both anterior and posterior vaginal wall support systems varied along different regions of vaginal wall for all three groups, with the highest compliance found near the vaginal apex and the lowest near the introitus. Women with cystocele had more compliant anterior and posterior vaginal wall support systems than women with rectocele. The movement direction differs between cystocele and rectocele. In cystocele, the anterior vaginal wall moves mostly toward the vaginal orifice in the upper vagina, but in a ventral direction in the lower vagina. In rectocele, the direction of the posterior vaginal wall movement is generally toward the vaginal orifice.

CONCLUSIONS

Movement of the vaginal wall and compliance of its support is quantifiable and was found to vary along the length of the vagina. Compliance was greatest in the upper vagina of all groups. Women with cystocele demonstrated the most compliant vaginal wall support.

Using stress MRI to analyze the 3D changes in apical ligament geometry from rest to maximal Valsalva: a pilot study

INTRODUCTION AND HYPOTHESIS

A method was developed using 3D stress magnetic resonance imaging (MRI) and was piloted to test hypotheses concerning changes in apical ligament lengths and lines of action from rest to maximal Valsalva.

METHODS

Ten women with (cases) and ten without (controls) pelvic organ prolapse (POP) were selected from an ongoing case-control study. Supine, multiplanar stress MRI was performed at rest and at maximal Valsalva and was imported into 3D Slicer v. 3.4.1 and aligned. The 3D reconstructions of the uterus and vagina, cardinal ligament (CL), deep uterosacral ligament (USL(d)), and pelvic bones were created. Ligament length and orientation were then measured.

RESULTS

Adequate ligament representations were possible in all 20 study participants. When cases were compared with controls, the curve length of the CL at rest was 71 ±16 mm vs. 59 ± 9 mm (p = 0.051), and the USL(d)was 38 ± 16 mm vs. 36 ± 11 mm (p = 0.797). Similarly, the increase in CL length from rest to strain was 30 ± 16 mm vs. 15 ± 9 mm (p = 0.033), and USL(d) was 15 ± 12 mm vs. 7 ± 4 mm (p = 0.094). Likewise, the change in USL(d) angle was significantly different from CL (p < 0.001).

CONCLUSIONS

This technique allows quantification of 3D geometry at rest and at strain. In our pilot sample, at maximal Valsalva, CL elongation was greater in cases than controls, whereas USL(d) was not; CL also exhibited greater changes in ligament length, and USL(d) exhibited greater changes in ligament inclination angle.

Posterior vaginal prolapse shape and position changes at maximal Valsalva seen in 3-D MRI-based models

INTRODUCTION AND HYPOTHESIS

Two-dimensional magnetic resonance imaging (MRI) of posterior vaginal prolapse has been studied. However, the three-dimensional (3-D) mechanisms causing such prolapse remain poorly understood. This discovery project was undertaken to identify the different 3-D characteristics of models of rectocele-type posterior vaginal prolapse (PVP(R)) in women.

METHODS

Ten women with (cases) and ten without (controls) PVP(R) were selected from an ongoing case-control study. Supine, multiplanar MR imaging was performed at rest and maximal Valsalva. Three-dimensional reconstructions of the posterior vaginal wall and pelvic bones were created using 3D Slicer v. 3.4.1. In each slice the posterior vaginal wall and perineal skin were outlined to the anterior margin of the external anal sphincter to include the area of the perineal body. Women with predominant enteroceles or anterior vaginal prolapse were excluded.

RESULTS

The case and control groups had similar demographics. In women with PVP(R) two characteristics were consistently visible (10/10): (1) the posterior vaginal wall displayed a folding phenomenon similar to a person beginning to kneel ("kneeling" shape) and (2) a downward displacement in the upper two thirds of the vagina. Also seen in some, but not all of the scans were: (3) forward protrusion of the distal vagina (6/10), (4) perineal descent (5/10), and (5) distal widening in the lower third of the vagina (3/10).

CONCLUSIONS

Increased folding (kneeling) of the vagina and an overall downward displacement are consistently present in rectocele. Forward protrusion, perineal descent, and distal widening are sometimes seen as well.