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

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

Frequency and trends in usage of eponyms in gynecologic anatomical terminology: A cross-sectional culturonomics study

On average, gynecologic eponyms were used more than twice as frequently as their preferred anatomical synonyms in published printed sources between 2000 and 2019.

Dynamic analysis of the individual patterns of intakes, voids, and bladder sensations reported in bladder diaries collected in the LURN study

The goal of this study was to develop the novel analytical approach and to perform an in-depth dynamic analysis of individual bladder diaries to inform which behavioral modifications would best reduce lower urinary tract symptoms, such as frequency and urgency. Three-day bladder diaries containing data on timing, volumes, and types of fluid intake, as well as timing, volumes, and bladder sensation at voids were analyzed for 197 participants with lower urinary tract symptoms. A novel dynamic analytic approach to bladder diary time series data was proposed and developed, including intra-subject correlations between time-varying variables: rates of intake, bladder filling rate, and urge growth rate. Grey-box models of bladder filling rate and multivariable linear regression models of urge growth rate were developed for individual diaries. These models revealed that bladder filling rate, rather than urine volume, was the primary determinant of urinary frequency and urgency growth rate in the majority of participants. Simulations performed with the developed models predicted that the most beneficial behavioral modifications to reduce the number of urgency episodes are those that smooth profiles of bladder filling rate, which might include behaviors such as exclusion of caffeine and alcohol and/or other measures, e.g., increasing number and decreasing volumes of intakes.

Dynamic analysis of the individual patterns of intakes, voids, and bladder sensations reported in bladder diaries collected in the LURN study

The goal of this study was to perform an in-depth dynamic analysis of individual bladder diaries to inform which behavioral modifications would best reduce lower urinary tract symptoms, such as frequency and urgency. Three-day bladder diaries containing data on timing, volumes, and types of fluid intake, as well as timing, volumes, and bladder sensation at voids were analyzed for 197 participants with lower urinary tract symptoms. A novel dynamic analytic approach to bladder diary time series data was proposed and developed, including intra-subject correlations between time-varying variables: rates of intake, bladder filling rate, and urge growth rate. Grey-box models of bladder filling rate and multivariable linear regression models of urge growth rate were developed for individual diaries. These models revealed that bladder filling rate, rather than urine volume, was the primary determinant of urinary frequency and urgency growth rate in the majority of participants. Simulations performed with the developed models predicted that the most beneficial behavioral modifications to reduce the number of urgency episodes are those that smooth profiles of bladder filling rate, which might include behaviors such as exclusion of caffeine and alcohol and/or other measures, e.g., increasing number and decreasing volumes of intakes.

Electrochemical Sensing of Urinary Chloride Ion Concentration for Near Real-Time Monitoring

Urinary chloride concentration is a valuable health metric that can aid in the early detection of serious conditions, such as acid base disorders, acute heart failure, and incidences of acute renal failure in the intensive care unit. Physiologically, urinary chloride levels frequently change and are difficult to measure, involving time-consuming and inconvenient lab testing. Thus, near real-time simple sensors are needed to quickly provide actionable data to inform diagnostic and treatment decisions that affect health outcomes. Here, we introduce a chronopotentiometric sensor that utilizes commercially available screen-printed electrodes to accurately quantify clinically relevant chloride concentrations (5-250 mM) in seconds, with no added reagents or electrode surface modification. Initially, the sensor's performance was optimized through the proper selection of current density at a specific chloride concentration, using electrical response data in conjunction with scanning electron microscopy. We developed a unique swept current density algorithm to resolve the entire clinically relevant chloride concentration range, and the chloride sensors can be reliably reused for chloride concentrations less than 50 mM. Lastly, we explored the impact of pH, temperature, conductivity, and additional ions (i.e., artificial urine) on the sensor signal, in order to determine sensor feasibility in complex biological samples. This study provides a path for further development of a portable, near real-time sensor for the quantification of urinary chloride.

Hiatal failure: effects of pregnancy, delivery, and pelvic floor disorders on level III factors

INTRODUCTION AND HYPOTHESIS

The failure of the levator hiatus (LH) and urogenital hiatus (UGH) to remain closed is not only associated with pelvic floor disorders, but also contributes to recurrence after surgical repair. Pregnancy and vaginal birth are key events affecting this closure. An understanding of normal and failed hiatal closure is necessary to understand, manage, and prevent pelvic floor disorders.

METHODS

This narrative review was conducted by applying the keywords "levator hiatus" OR "genital hiatus" OR "urogenital hiatus" in PubMed. Articles that reported hiatal size related to pelvic floor disorders and pregnancy were chosen. Weighted averages for hiatal size were calculated for each clinical situation.

RESULTS

Women with prolapse have a 22% and 30% larger LH area measured by ultrasound at rest and during Valsalva than parous women with normal support. Women with persistently enlarged UGH have 2-3 times higher postoperative failure rates after surgery for prolapse. During pregnancy, the LH area at Valsalva increases by 29% from the first to the third trimester in preparation for childbirth. The enlarged postpartum hiatus recovers over time, but does not return to nulliparous size after vaginal birth. Levator muscle injury during vaginal birth, especially forceps-assisted, is associated with increases in hiatal size; however, it only explains a portion of hiatus variation-the rest can be explained by pelvic muscle function and possibly injury to other level III structures.

CONCLUSIONS

Failed hiatal closure is strongly related to pelvic floor disorders. Vaginal birth and levator injury are primary factors affecting this important mechanism.

Comparison of in vivo visco-hyperelastic properties of uterine suspensory tissue in women with and without pelvic organ prolapse

The uterine suspensory tissue (UST) complex includes the cardinal (CL) and uterosacral "ligaments" (USL), which are mesentery-like structures that play a role in resisting pelvic organ prolapse (POP). Since there is no information on the time-dependent material properties of the whole structure in situ and in vivo, we developed and tested an intraoperative technique to quantify in vivo whether there is a significant difference in visco-hyperelastic behavior of the CL and USL between women with and without POP. Thirteen women with POP (cases) and four controls scheduled for surgery were selected from an ongoing POP study. Immediately prior to surgery, a computer-controlled linear servo-actuator with a series force transducer applied a continuous, caudally directed traction force while simultaneously recording the resulting cervical displacement in the same direction. After applying an initial 1.1 N preload, a ramp rate of 4 mm/s was used to apply a maximum force of 17.8 N in three "ramp-and-hold" test trials. A simplified bilateral four-cable biomechanical model was used to identify the material behavior of each ligament. For this, the initial cross-section areas of the CL and USL were measured on 3-T magnetic resonance image-based 3D models from each subject. The time-dependent strain energy function of CL/USL was defined with a three-parameter hyperelastic Mooney-Rivlin material model and a two-term Prony series in relaxation form. When cases were compared with controls, the estimated time-dependent material constants of CL and USL did not differ significantly. These are the first measurements that compare the in vivo and in situ visco-hyperelastic response of the tissues comprising the CL and USL to loading in women with and without prolapse. Larger sample sizes would help improve the precision of intergroup differences.

Natural history of lower urinary tract symptoms in treatment-seeking women with pelvic organ prolapse; the Symptoms of Lower Urinary Tract Dysfunction Research Network (LURN)

BACKGROUND

The association of pelvic organ prolapse with overactive bladder and other lower urinary tract symptoms, and the natural history of those symptoms are not well characterized. Previous cross-sectional studies demonstrated conflicting relationships between prolapse and lower urinary tract symptoms.

OBJECTIVE

This study primarily aimed to determine the baseline association between lower urinary tract symptoms and prolapse and to assess longitudinal differences in symptoms over 12 months in women with and without prolapse. Secondary aims were to explore associations between lower urinary tract symptoms and prolapse treatment. We hypothesized that: (1) prolapse is associated with the presence of lower urinary tract symptoms, (2) lower urinary tract symptoms are stable over time in patients with and without prolapse, and (3) prolapse treatment is associated with lower urinary tract symptom improvement.

STUDY DESIGN

Women enrolled in the Symptoms of Lower Urinary Tract Dysfunction Research Network Observational Cohort Study with adequate 12-month follow-up data were included. Prolapse and lower urinary tract symptom treatment during follow-up was guided by standard of care. Outcome measures included the Lower Urinary Tract Symptoms Tool total severity score (in addition to overactive bladder, obstructive, and stress urinary incontinence subscales) and Urogenital Distress Inventory-6 Short Form. Prolapse (yes or no) was defined primarily when Pelvic Organ Prolapse Quantification System points Ba, C or Bp were >0 (beyond the hymen). Mixed-effects models with random effects for patient slopes and intercepts were fitted for each lower urinary tract symptom outcome and prolapse predictor, adjusted for other covariates. The study had >90% power to detect differences as small as 0.4 standard deviation for less prevalent group comparisons (eg, prolapse vs not).

RESULTS

A total of 371 women were analyzed, including 313 (84%) with no prolapse and 58 (16%) with prolapse. Women with prolapse were older (64.6±8.8 vs 55.3±14.1 years; P<.001) and more likely to have prolapse surgery (28% vs 1%; P<.001) and pessary treatment (26% vs 4%; P<.001) during the study. Average baseline Lower Urinary Tract Symptoms Tool total severity scores were lower (fewer symptoms) for participants with prolapse compared with those without (38.9±14.0 vs 43.2±14.0; P=.036), but there were no differences in average scores between prolapse groups for other scales. For all urinary outcomes, average scores were significantly lower (improved) at 3 and 12 months compared with baseline (all P<.05). In mixed-effects models, there were no statistically significant interactions between pelvic organ prolapse measurement and visit and time-dependent prolapse treatment groups (P>.05 for all regression interaction coefficients). The Lower Urinary Tract Symptoms Tool obstructive severity score had a statistically significant positive association with Pelvic Organ Prolapse Quantification System Ba, Bp, and point of maximum vaginal descent. The Lower Urinary Tract Symptoms Tool total severity scale had a statistically significant negative association with Pelvic Organ Prolapse Quantification System Ba and point of maximum vaginal descent. No other associations between prolapse and lower urinary tract symptoms were significant (P>.05 for all regression coefficients). Symptom differences between prolapse groups were small: all regression coefficients (interpretable as additive percentage change in each score) were between -5 and 5 (standard deviation of outcomes ranged from 14.0-32.4).

CONCLUSION

Among treatment-seeking women with urinary symptoms, obstructive symptoms were positively associated with prolapse, and overall lower urinary tract symptom severity was negatively associated with prolapse. Lower Urinary Tract Symptoms Tool scores improved over 12 months regardless of prolapse status, including in those with treated prolapse, untreated prolapse, and without prolapse.

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

INTRODUCTION AND HYPOTHESIS

We aimed to develop a deep learning-based multi-label classification model to simultaneously diagnose three types of pelvic organ prolapse using stress magnetic resonance imaging (MRI).

METHODS

Our dataset consisted of 213 midsagittal labeled MR images at maximum Valsalva. For each MR image, the two endpoints of the sacrococcygeal inferior-pubic point line were auto-localized. Based on this line, a region of interest was automatically selected as input to a modified deep learning model, ResNet-50, for diagnosis. An unlabeled MRI dataset, a public dataset, and a synthetic dataset were used along with the labeled image dataset to train the model through a novel training strategy. We conducted a fivefold cross-validation and evaluated the classification results using precision, recall, F1 score, and area under the curve (AUC).

RESULTS

The average precision, recall, F1 score, and AUC of our proposed multi-label classification model for the three types of prolapse were 0.84, 0.72, 0.77, and 0.91 respectively, which were improved from 0.64, 0.53, 0.57, and 0.83 from the original ResNet-50. Classification took 0.18 s to diagnose one patient.

CONCLUSIONS

The proposed deep learning-based model were demonstrated feasible and fast in simultaneously diagnosing three types of prolapse based on pelvic floor stress MRI, which could facilitate computer-aided prolapse diagnosis and treatment planning.

Pelvic inclination correction system for magnetic resonance imaging analysis of pelvic organ prolapse in upright position

INTRODUCTION AND HYPOTHESIS

Pelvic organ prolapse quantification by means of upright magnetic resonance imaging (MRI) is a promising research field. This study determines the angle for the pelvic inclination correction system (PICS) for upright patient position, which is hypothesized to deviate from the supine PICS angle. The necessity of different PICS angles for various patient positions will also be discussed.

METHODS

Magnetic resonance scans of 113 women, acquired in an upright patient position, were used to determine the upright PICS angle, defined as the angle between the sacrococcygeal-inferior pubic point (SCIPP) line and the horizontal line. The difference and correlation between the upright and supine PICS angles were calculated using the paired Student's t-test and the Pearson's correlation coefficient (r) respectively. The effect of the difference between the upright and supine PICS angle on the measured pelvic organ extent was calculated using goniometry.

RESULTS

The mean (interquartile range) PICS angles were 29° (26-35°) for the upright and 33° (30-37°) for the supine patient position. They were significantly different (p<0.001) and very strongly correlated (r = 0.914, p<0.001). The 4° difference between the average upright and supine PICS angle results in an average underestimation of the measured cervix height of approximately 0.5 cm for patients scanned in upright position.

CONCLUSIONS

The PICS angle for the upright patient position is 29°. The use of a dedicated PICS angle for different patient positions allows for more accurate pelvic organ extent analysis in patients with prolapse.

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.

Changes in cardinal ligament length and curvature with parity and prolapse and their relation to level III hiatus measures

INTRODUCTION AND HYPOTHESIS

Test the hypotheses that (1) cardinal ligament (CL) straightening and lengthening occur with parity and prolapse, (2) CL straightening occurs before lengthening, and (3) CL length is correlated with level III measures.

METHODS

We performed a secondary analysis of MRIs from women in three groups: (1) nulliparous with normal support, (2) parous with normal support, and (3) uterine prolapse (POP-Q point C > - 4 and Ba > 1 cm). The 3D stress MRI images at rest and maximal Valsalva were analyzed. CLs were traced from their origin to cervico-vaginal insertions. Curvature ratio was calculated as curved length/straight length. Level III measures included urogenital hiatus (UGH), levator hiatus (LH), and levator bowl volume (LBV), and their correlations with CL length were calculated.

RESULTS

Ten women were included in each group. Compared to the nulliparous group, CL length was 18% longer in parous controls (p = .04) and 59% longer with prolapse (p < .01) at rest, while at Valsalva, CL length was 10% longer in parous controls (p = .21) and 49% longer with prolapse (p < .01). Curvature ratios showed 18% more straightening in women with prolapse compared to parous controls (p < .01). Curved CL length and level III measures were moderately to strongly correlated: UGH (rest: R = 0.68, p < .01; Valsalva: R =0.80, p < .01), LH (rest: R = 0.60, p < .01; Valsalva: R = 0.78, p < .01), and LBV (rest: R = 0.71, p < .01; Valsalva: R =0.89, p < .01).

CONCLUSION

Our findings suggest that the CLs undergo three times as much lengthening with prolapse as with parity; however, straightening only occurs with prolapse. Strong correlations exist between level I and level III support.

Novel 3D MRI technique to measure perineal membrane structural changes with pregnancy and childbirth: Technique development and measurement feasibility

INTRODUCTION AND HYPOTHESIS

We aimed to develop and validate a new MRI-based perineal membrane reconstruction and morphological measurement technique, and test its feasibility on nulliparous and parous women to determine the effects of pregnancy and childbirth on the perineal membrane.

METHODS

The perineal membrane was traced on high-resolution MRI using 3D Slicer® and analyses performed using Rhinoceros 6.0 SR23®. Validation was done by comparing MRI-based perineal membrane reconstruction to dissection measurements in a cadaver. Feasibility of reconstruction was assessed in the following three groups: nulliparous (NP), primiparous women who underwent cesarean delivery (CD), and primiparous women with vaginal delivery (VD). The following parameters were measured: (1) swinging door angle, (2) bony and (3) soft tissue attachment lengths, (4) separation at perineal body level, (5) surface area, and (6) hiatal area. ANOVA and post-hoc comparisons were performed, and the effect sizes (d) were reported.

RESULTS

Model reconstruction was similar to cadaver dissection findings. Morphological measurements were feasible in all women (NP, n = 10; CS, n = 6; VD, n = 19). Swinging door angle was 13^o greater in CD (p = 0.03; d = 1.15) and 16^o greater in VD (p < 0.001; d = 1.41) compared to NP. VD showed 13% larger separation at the perineal body than NP (p = 0.097, d = 0.84) and 23% larger hiatal area than CD (p = 0.14, d = 0.94).

CONCLUSION

This novel and anatomically validated MRI-based perineal membrane reconstruction technique is feasible. Preliminary findings show that pregnancy and childbirth both influence perineal membrane morphology with VD being associated with the largest swinging door angle and perineal body separation.

Symptom Based Clustering of Men in the LURN Observational Cohort Study

PURPOSE

Conventional classification of patients with lower urinary tract symptoms into diagnostic categories based on a predefined symptom complex or predominant symptom appears inadequate. This is due to the frequent presentation of patients with multiple urinary symptoms which could not be perfectly categorized into traditional diagnostic groups. We used a novel clustering method to identify subtypes of male patients with lower urinary tract symptoms based on detailed multisymptom information.

MATERIALS AND METHODS

We analyzed baseline data on 503 care seeking men in the LURN (Symptoms of Lower Urinary Tract Dysfunction Research Network) Observational Cohort Study. Symptoms and symptom severity were assessed using the LUTS (Lower Urinary Tract Symptoms) Tool and the AUA SI (American Urological Association Symptom Index), which include a total of 52 questions. We used a resampling based consensus clustering algorithm to identify patient subtypes with distinct symptom signatures.

RESULTS

Four distinct symptom clusters were identified. The 166 patients in cluster M1 had predominant symptoms of frequency, nocturia, hesitancy, straining, weak stream, intermittency and incomplete bladder emptying suggestive of bladder outlet obstruction. The 93 patients in cluster M2 mainly endorsed post-micturition symptoms (eg post-void dribbling and post-void leakage) with some weak stream. The 114 patients in cluster M3 reported mostly urinary frequency without incontinence. The 130 patients in cluster M4 reported severe frequency, urgency and urgency incontinence. Most other urinary symptoms statistically differed between cluster pairs. Patient reported outcomes of bowel symptoms, mental health, sleep dysfunction, erectile function and urological pain significantly differed across the clusters.

CONCLUSIONS

We identified 4 data derived clusters among men seeking care for lower urinary tract symptoms. The clusters differed from traditional diagnostic categories. Further subtype refinement will be done to incorporate clinical data and nonurinary patient reported outcomes.

Longitudinal changes in symptom-based female and male LUTS clusters

AIMS

Lower urinary tract symptoms (LUTS) are diverse in type and variable in severity. We examined symptom change within the Symptoms of the Lower Urinary Tract Dysfunction Research Network (LURN) Observational Cohort study identified clusters over time and tested associations with treatments received.

METHODS

Patient-reported LUTS and treatment data were collected at multiple time points between baseline and 12 months from the LURN Observational Cohort study. LUTS severity scores were calculated to summarize changes in symptom reporting over time in previously identified LURN clusters. Repeated measures linear regression models tested adjusted associations between cluster membership and severity scores.

RESULTS

Four-hundred seventeen men and 396 women were classified into improved, unchanged, and worsened symptoms between baseline and 12 months (men: 44.1%, 40.5%, and 15.3%; women: 55.8%, 33.1%, 11.1%, respectively). Improvement in LUTS severity scores varied by cluster (estimated adjusted mean change from baseline range: -.04 change in standard deviations of severity scores (ΔSD) to -.67 ΔSD). Prostate surgery was associated with improved severity scores (-.63 ΔSD) in men, while stress incontinence surgery was associated with improved severity scores (-.88 ΔSD) in women.

CONCLUSION

Symptom improvement varied by cluster indicating response to therapy differs amongst subtypes of patients with LUTS. The differential improvement of patients in clusters suggests mechanistic differences between clusters and may aid in selecting more targeted treatments in the future.

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.

The Distribution of Post-Void Residual Volumes in People Seeking Care in the Symptoms of Lower Urinary Tract Dysfunction Network Observational Cohort Study With Comparison to Asymptomatic Populations

OBJECTIVE

To describe the distribution of post-void residual (PVR) volumes across patients with and without lower urinary tract symptoms (LUTS) and examine relationships between self-reported voiding symptoms, storage symptoms, and PVR.

METHODS

PVR and demographic data were obtained from the Symptoms of Lower Urinary Tract Dysfunction Research Network (LURN) observational cohort study. Self-reported symptoms were collected using the American Urological Association Symptom Index and the LUTS Tool. PVR values were obtained from 2 other cohorts: living kidney donors with unknown LUTS from the Renal and Lung Living Donors Evaluation Study (RELIVE), and continent women in the Establishing the Prevalence of Incontinence (EPI) study, a population-based study of racial differences in urinary incontinence prevalence.

RESULTS

Across the 3 studies, median PVRs were similar: 26 mL in LURN (n = 880, range 0-932 mL), 20 mL in EPI (n = 166, range 0-400 mL), and 14 mL in RELIVE (n = 191, range 0-352 mL). In LURN, males had 3.6 times higher odds of having PVR > 200 mL (95% CI = 1.72-7.48). In RELIVE, median PVR was significantly higher for males (20 mL vs 0 mL, P= .004). Among women, only the intermittency severity rating was associated with a probability of an elevated PVR. Among men, incomplete emptying and burning severity rating were associated with a higher odds of elevated PVR, but urgency severity ratings were associated with lower odds of elevated PVR.

CONCLUSION

Care-seeking patients have PVRs similar to those in people with unknown history of LUTS (RELIVE) and without self-reported LUTS (EPI). Although PVR was correlated with voiding symptoms, the mean differences only explain ∼2% of the variance.

Are three-day voiding diaries feasible and reliable? Results from the Symptoms of Lower Urinary Tract Dysfunction Research Network (LURN) cohort

AIMS

The aims of this study were to assess the completeness of voiding diaries in a research context and to correlate diary data with patient-reported questionnaires.

METHODS

Men and women enrolled in the Symptoms of Lower Urinary Tract Dysfunction Research Network (LURN) were given a 3-day voiding and fluid-intake diary to fill-out. Diaries were assessed for completeness and intake-output imbalances. They were assigned to one of four categories based on a percentage of missing data and fluid imbalance: no diary submitted, unusable (>40% missing void or intake volumes, or unphysiological fluid imbalance), usable but not complete, and complete.

RESULTS

A total of 1064 participants were enrolled and 85% (n = 902) returned the bladder diary. Of the diaries returned, 94% (n = 845) had data on three separate days, 87% (n = 786) had no missing intake volumes, 61% (n = 547) had no missing voided volumes, and 70% (n = 635) had a fluid imbalance within 3 L across the 3-day time period, resulting in 50% (n = 448) of participants with 100% complete diaries. Younger age was associated with a higher likelihood of not submitting a diary, or submitting an unusable diary. Women had a higher likelihood of submitting an unusable diary or a usable but incomplete diary.

CONCLUSION

Overall, 50% of LURN participants returned voiding diaries with perfectly complete data. Incomplete data for voided volumes was the most common deficiency. There was only a moderate correlation between diary data and questionnaire responses, indicating that diaries are a source of unique information.

Symptom Based Clustering of Women in the LURN Observational Cohort Study

PURPOSE

Women with lower urinary tract symptoms are often diagnosed based on a predefined symptom complex or a predominant symptom. There are many limitations to this paradigm as often patients present with multiple urinary symptoms which do not perfectly fit the preestablished diagnoses. We used cluster analysis to identify novel, symptom based subtypes of women with lower urinary tract symptoms.

MATERIALS AND METHODS

We analyzed baseline urinary symptom questionnaire data obtained from 545 care seeking female participants enrolled in the LURN (Symptoms of Lower Urinary Tract Dysfunction Research Network) Observational Cohort Study. Symptoms were measured with the LUTS (lower urinary tract symptoms) Tool and the AUA SI (American Urological Association Symptom Index), and analyzed using a probability based consensus clustering algorithm.

RESULTS

Four clusters were identified. The 138 women in cluster F1 did not report incontinence but experienced post-void dribbling, frequency and voiding symptoms. The 80 women in cluster F2 reported urgency incontinence as well as urgency and frequency but minimal voiding symptoms or stress incontinence. Cluster F3 included 244 women who reported all types of incontinence, urgency, frequency and mild voiding symptoms. The 83 women in cluster F4 reported all lower urinary tract symptoms at uniformly high levels. All but 2 of 44 LUTS Tool and 8 AUA SI questions significantly differed between at least 2 clusters (p <0.05). All clusters contained at least 1 member from each conventional group, including continence, and stress, urgency, mixed and other incontinence.

CONCLUSIONS

Women seeking care for lower urinary tract symptoms cluster into 4 distinct symptom groups which differ from conventional clinical diagnostic groups. Further validation is needed to determine whether management improves using this new classification.

Technique development and measurement of cross-sectional area of the pubovisceral muscle on MRI scans of living women

INTRODUCTION AND HYPOTHESIS

Measurements of the anatomic cross-sectional area (CSA) of the pubovisceral muscle (PVM) in women are confounded by the difficulty of separating the muscle from the adjacent puborectal (PRM) and iliococcygeal (ICM) muscles when visualized in a plane orthogonal to the fiber direction. We tested the hypothesis that it might be possible to measure the PVM CSA within a defined region of interest based on magnetic resonance images (MRI).

METHODS

MRI scans of 11 women with unilateral PVM tears and seven primiparous women with intact muscles following elective C-section were used to identify the PVM injury zone defined by the mean location of its boundaries with the adjacent intact PRM and ICM from existing anatomic reference points using 3D Slicer and ImageJ software. Then, from the 15 or more 2-mm transverse slices available, the slice with the maximum anatomic CSA of the left and right PVM was found in 24 primiparous women with bilaterally intact muscles who had delivered via C-section.

RESULTS

Mean [± standard deviation (SD)] of the maximum left or right PVM cross-section areas for the 24 women, measured by two different raters, was 1.25 ± 0.29 cm² (range 0.75-1.86). The 5th, 50th, and 95th percentile values were 0.77, 1.23, and 1.80 cm², respectively. Inter- and intrarater measurement repeatability intraclass correlation coefficients exceeded 0.89 and 0.90, respectively.

CONCLUSIONS

It is possible to use MRI to identify the volume of interest with the maximum anatomic cross section of the PVM belly while minimizing the inadvertent inclusion of adjacent PRM or ICM in that measurement.

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.

Magnetic resonance imaging of vaginal support structure before and after Vecchietti procedure in women with Mayer-Rokitansky-Küster-Hauser syndrome

INTRODUCTION

It is unclear how pelvic floor supporting structures might be affected by the absence of the vagina. It was the aim of this prospective study to analyze the magnetic resonance imaging morphology of pelvic support prior and after a Vecchietti procedure in women suffering Mullerian agenesis (Mayer-Rokitansky-Küster-Hauser syndrome).

MATERIAL AND METHODS

26 women with a diagnosis of Mayer-Rokitansky-Küster-Hauser syndrome associated vaginal agenesis were recruited prospectively prior to the laparoscopic creation of a neovagina according to the Vecchietti procedure. The primary outcome measure was the magnetic resonance imaging morphology of supporting structures. Secondary outcome measures were anatomical and functional vaginal length. Follow up was conducted six months after surgery.

RESULTS

Twenty-six women were analyzed. Mean age was 19.8 ± 4.4 years (±SD) and mean body mass index was 23.7 ± 4.3 kg/m² (±SD). All were Caucasian. Supporting structures consistent with cardinal and uterosacral ligaments were visible on magnetic resonance imaging in all cases (100%). There were no levator ani defects. The vaginal apex could be visualized postoperatively in 12 women (46.2%) reaching up to Level I. The vagina was visible in both Level II and III with normal relations to the pelvic walls in all cases. On gynecological examination, vaginal length was 8.8 ± 2.1 cm (mean ± SD) anatomically and 10.2 ± 2.2 cm (mean ± SD) functionally.

CONCLUSIONS

The preoperative presence of pelvic support structures into which the vagina is lengthened by the surgery likely explains the uncommon occurrence of vaginal prolapse in women who had the Vecchietti procedure.

The 3D Pelvic Inclination Correction System (PICS): A universally applicable coordinate system for isovolumetric imaging measurements, tested in women with pelvic organ prolapse (POP)

In pelvic organ prolapse (POP), the organs are pushed downward along the lines of gravity, so measurements along this longitudinal body axis are desirable. We propose a universally applicable 3D coordinate system that corrects for changes in pelvic inclination and that allows the localization of any point in the pelvis at rest or under dynamic conditions on magnetic resonance images (MRI) of pelvic floor disorders in a scanner- and software independent manner. The proposed 3D coordinate system called 3D Pelvic Inclination Correction System (PICS) is constructed utilizing four bony landmark points, with the origin set at the inferior pubic point, and three additional points at the sacrum (sacrococcygeal joint) and both ischial spines, which are clearly visible on MRI images. The feasibility and applicability of the moving frame was evaluated using MRI datasets from five women with pelvic organ prolapse, three undergoing static MRI and two undergoing dynamic MRI of the pelvic floor in a supine position. The construction of the coordinate system was performed utilizing the selected landmarks, with an initial implementation completed in MATLAB. In all cases the selected landmarks were clearly visible, with the construction of the 3D PICS and measurement of pelvic organ positions performed without difficulty. The resulting distance from the organ position to the horizontal PICS plane was compared to a traditional measure based on standard measurements in 2D slices. The two approaches demonstrated good agreement in each of the cases. The developed approach makes quantitative assessment of pelvic organ position in a physiologically relevant 3D coordinate system possible independent of pelvic movement relative to the scanner. It allows the accurate study of the physiologic range of organ location along the body axis ("up or down") as well as defects of the pelvic sidewall or birth-related pelvic floor injuries outside the midsagittal plane, not possible before in a 2D reference line system. Measures in 3D can be monitored over time and may reveal pathology before bothersome symptoms appear, as well as allowing comparison of outcomes between different patient pools after different surgical approaches.

Defining Patient Knowledge and Perceptions of Vaginal Pessaries for Prolapse and Incontinence

OBJECTIVE

The aim of this study was to define patient knowledge and perceptions of pessaries to identify barriers to care and inform physician counseling efforts.

METHODS

An anonymous survey was distributed to a convenience sample of new patients presenting to the urogynecology clinic at a single academic medical center. Data analysis was performed using standard bivariate and logistic regression models.

RESULTS

A total of 254 women completed the survey. Only half of respondents indicated prior knowledge of pessaries. The most common source of prior knowledge was a physician or other health care provider (100/130, 76.9%); comparatively few women had heard about pessaries from any other source. Patients presented with a negative view of pessaries, 3.6 ± 2.2 on a 0- to 10-point Likert scale, and only a third of patients indicated they would consider pessary use as a treatment option for their condition. On multivariable logistic regression, having previously seen a gynecologist (P = 0.03) and a lower level of education (P = 0.05) independently predicted aversion to pessary use.

CONCLUSIONS

Only half of patients presenting to a referral-based practice had previous knowledge of vaginal pessaries. Few patients had heard about pessaries from any source other than a physician or other health care provider. Patients presented with a negative impression of pessaries and a high level of aversion to pessary use. Patients who indicated they would decline pessary use reported a lower level of education and were more likely to have previously seen a gynecologist for evaluation of their condition. These data may inform physician counseling efforts.

Traction force needed to reproduce physiologically observed uterine movement: technique development, feasibility assessment, and preliminary findings

INTRODUCTION AND HYPOTHESIS

This study aimed to describe a novel strategy to determine the traction forces needed to reproduce physiologic uterine displacement in women with and without prolapse.

METHODS

Participants underwent dynamic stress magnetic resonance imaging (MRI) testing as part of a study examining apical uterine support. Physiologic uterine displacement was determined by analyzing uterine location in images taken at rest and at maximal Valsalva. Force-displacement curves were calculated based on intraoperative cervical traction testing. The intraoperative force required to achieve the uterine displacement measured during MRI was then estimated from these curves. Women were categorized into three groups based on pelvic organ support: group 1 (normal apical and vaginal support), group 2 (normal apical support but vaginal prolapse present), and group 3 (apical prolapse).

RESULTS

Data from 19 women were analyzed: five in group 1, five in group 2, and nine in group 3. Groups were similar in terms of age, body mass index (BMI), and parity. Median operating room (OR) force required for uterine displacement measured during MRI was 0.8 N [interquartile range (IQR) 0.62-3.22], and apical ligament stiffness determined using MRI uterine displacement was 0.04 N/mm (IQR 0.02-0.08); differences between groups were nonsignificant. Uterine locations determined at rest and during maximal traction were lower in the OR compared with MRI in all groups.

CONCLUSIONS

Using this investigative strategy, we determined that only 0.8 N of traction force in the OR was required to achieve maximal physiologic uterine displacement seen during dynamic (maximal Valsalva) MRI testing, regardless of the presence or absence of prolapse.

Quantitative analyses of variability in normal vaginal shape and dimension on MR images

INTRODUCTION AND HYPOTHESIS

We present a technique for quantifying inter-individual variability in normal vaginal shape, axis, and dimension, and report findings in healthy women.

METHODS

Eighty women (age: 28∼70 years) with normal pelvic organ support underwent supine, multi-planar proton-density MRI. Vaginal width was assessed at five evenly-spaced locations, and vaginal axis, length, and surface area were quantified via ImageJ and MATLAB.

RESULTS

The mid-sagittal plane angles, relative to the horizontal, of three vaginal axes were 90 ± 11, 72 ± 21, and 41 ± 22° (caudal to cranial, p < 0.001). The mean (± SD) vaginal widths were 17 ± 5, 24 ± 4, 30 ± 7, 41 ± 9, and 45 ± 12 mm at the five locations (caudal to cranial, p < 0.001). Mid-sagittal lengths for anterior and posterior vaginal walls were 63 ± 9 and 98 ± 18 mm respectively. The vaginal surface area was 72 ± 21 cm(2) (range: 34 ∼ 164 cm(2)). The coefficient of determination between any demographic variable and any vaginal dimension did not exceed 0.16.

CONCLUSIONS

Large variations in normal vaginal shape, axis, and dimensions were not explained by body size or other demographic variables. This variation has implications for reconstructive surgery, intravaginal and surgical product design, and vaginal drug delivery.

Evaluating maternal recovery from labor and delivery: bone and levator ani injuries

OBJECTIVE

We sought to describe occurrence, recovery, and consequences of musculoskeletal (MSK) injuries in women at risk for childbirth-related pelvic floor injury at first vaginal birth.

STUDY DESIGN

Evaluating Maternal Recovery from Labor and Delivery is a longitudinal cohort design study of women recruited early postbirth and followed over time. We report here on 68 women who had birth-related risk factors for levator ani (LA) muscle injury, including long second stage, anal tears, and/or older maternal age, and who were evaluated by MSK magnetic resonance imaging at both 7 weeks and 8 months' postpartum. We categorized magnitude of injury by extent of bone marrow edema, pubic bone fracture, LA muscle edema, and LA muscle tear. We also measured the force of LA muscle contraction, urethral pressure, pelvic organ prolapse, and incontinence.

RESULTS

In this higher-risk sample, 66% (39/59) had pubic bone marrow edema, 29% (17/59) had subcortical fracture, 90% (53/59) had LA muscle edema, and 41% (28/68) had low-grade or greater LA tear 7 weeks' postpartum. The magnitude of LA muscle tear did not substantially change by 8 months' postpartum (P = .86), but LA muscle edema and bone injuries showed total or near total resolution (P < .05). The magnitude of unresolved MSK injuries correlated with magnitude of reduced LA muscle force and posterior vaginal wall descent (P < .05) but not with urethral pressure, volume of demonstrable stress incontinence, or self-report of incontinence severity (P > .05).

CONCLUSION

Pubic bone edema and subcortical fracture and LA muscle injury are common when studied in women with certain risk factors. The bony abnormalities resolve, but levator tear does not, and is associated with levator weakness and posterior-vaginal wall descent.

In vivo properties of uterine suspensory tissue in pelvic organ prolapse

The uterine suspensory tissue (UST), which includes the cardinal (CL) and uterosacral ligaments (USL), plays an important role in resisting pelvic organ prolapse (POP). We describe a technique for quantifying the in vivo time-dependent force-displacement behavior of the UST, demonstrate its feasibility, compare data from POP patients to normal subjects previously reported, and use the results to identify the properties of the CL and USL via biomechanical modeling. Fourteen women with prolapse, without prior surgeries, who were scheduled for surgery, were selected from an ongoing study on POP. We developed a computer-controlled linear servo actuator, which applied a continuous force and simultaneously recorded cervical displacement. Immediately prior to surgery, the apparatus was used to apply three "ramp and hold" trials. After a 1.1 N preload was applied to remove slack in the UST, a ramp rate of 4 mm/s was used up to a maximum force of 17.8 N. Each trial was analyzed and compared with the tissue stiffness and energy absorbed during the ramp phase and normalized final force during the hold phase. A simplified four-cable model was used to analyze the material behavior of each ligament. The mean ± SD stiffnesses of the UST were 0.49 ± 0.13, 0.61 ± 0.22, and 0.59 ± 0.2 N/mm from trial 1 to 3, with the latter two values differing significantly from the first. The energy absorbed significantly decreased from trial 1 (0.27 ± 0.07) to 2 (0.23 ± 0.08) and 3 (0.22 ± 0.08 J) but not from trial 2 to 3. The normalized final relaxation force increased significantly with trial 1. Modeling results for trial 1 showed that the stiffnesses of CL and USL were 0.20 ± 0.06 and 0.12 ± 0.04 N/mm, respectively. Under the maximum load applied in this study, the strain in the CL and USL approached about 100%. In the relaxation phase, the peak force decreased by 44 ± 4% after 60 s. A servo actuator apparatus and intraoperative testing strategy proved successful in obtaining in vivo time-dependent material properties data in representative sample of POP. The UST exhibited visco-hyperelastic behavior. Unlike a knee ligament, the length of UST could stretch to twice their initial length under the maximum force applied in this study.

Validity and reliability of an instrumented speculum designed to minimize the effect of intra-abdominal pressure on the measurement of pelvic floor muscle strength

BACKGROUND

Measurements of pelvic floor muscle strength are contaminated by crosstalk from intra-abdominal pressure. We tested an improved instrumented speculum designed to minimize this crosstalk. The hypotheses were that the speculum yields: 1) maximum vaginal closure forces unrelated to intra-abdominal pressure, 2) discriminatory validity between women with strong vs. weak pelvic floor muscles, and 3) acceptable test-retest reliability.

METHODS

Maximum voluntary vaginal closure force was measured in 40 incontinent women (20-77 years) on two visits spaced one month apart. At the baseline visit, intra-abdominal pressure was also estimated via intra-vesical catheterization during the vaginal closure force measurement. Subjective estimate of pelvic floor muscle strength was also assessed using digital palpation by a skilled examiner to determine group placement as "strong" (n=31) or "weak" (n=9).

FINDINGS

Vaginal closure force was not significantly correlated with intra-abdominal pressure (r=-.26, P=.109). The groups with subjectively scored strong and weak pelvic floor muscles differed significantly by mean [SD] maximum vaginal closure force (3.8 [1.7] vs. 1.9 [0.8] N respectively, P<.01.) Across both time points the mean vaginal closure force was 3.42 [1.67] N with a range of .68 to 9.05 N. Mean Visit 1 and Visit 2 vaginal closure force scores did not differ (3.41 [1.8] and 3.42 [1.6] N, respectively). The vaginal closure force repeatability coefficient was 3.1N.

INTERPRETATION

The improved speculum measured maximum vaginal closure force without evidence of crosstalk from intra-abdominal pressure, while retaining acceptable discriminant validity and repeatability.

The rectovaginal septum: visible on magnetic resonance images of women with Mayer-Rokitansky-Küster-Hauser syndrome (Müllerian agenesis)

INTRODUCTION AND HYPOTHESIS

Ongoing debate exists about whether the rectovaginal septum (Denonvilliers' fascia) is myth or reality. This study evaluates magnetic resonance images (MRI) of women with Müllerian agenesis for the presence of fascial layers between the rectum and the bladder to test the hypothesis that this layer exists in the absence of the vagina.

METHODS

This is a secondary analysis of a study describing MRI aspects in women with vaginal agenesis before and after laparoscopic Vecchietti procedure. Study participants (n =16) had a multiplanar pelvic MR scan. Images were evaluated independently by two investigators (MH, JOLD) for the appearance of layers separate from the bladder and rectum in the area of interest, with characteristic anatomical features of the septum.

RESULTS

Participants' mean age was 19.4±2.6 years ± standard deviation (SD). In 12 of 16 patients (75 %) a distinct layer between rectum and bladder was identified in either the axial(4/16; 25 %) or sagittal (12/16; 75 %) scan or both. Characteristic anatomical features included lateral attachment to the levator ani muscle, cranial fusion to the cul-de-sac peritoneum,and caudal insertion into the perineal body.Conclusions Three quarters of women with Müllerian agenesis have a visible layer between bladder and rectum. As none of the participants had a vagina, these results support the existence of a rectovaginal septum, separate from a vaginal adventitia.

Comparison of muscle fiber directions between different levator ani muscle subdivisions: in vivo MRI measurements in women

INTRODUCTION AND HYPOTHESIS

This study describes a technique to quantify muscle fascicle directions in the levator ani (LA) and tests the null hypothesis that the in vivo fascicle directions for each LA subdivision subtend the same parasagittal angle relative to a horizontal reference axis.

METHODS

Visible muscle fascicle direction in the each of the three LA muscle subdivisions, the pubovisceral (PVM; synonymous with pubococcygeal), puborectal (PRM), and iliococcygeal (ICM) muscles, as well as the external anal sphincter (EAS), were measured on 3-T sagittal MRI images in a convenience sample of 14 healthy women in whom muscle fascicles were visible. Mean ± standard deviation (SD) angle values relative to the horizontal were calculated for each muscle subdivision. Repeated measures ANOVA and post-hoc paired t tests were used to compare muscle groups.

RESULTS

Pubovisceral muscle fiber inclination was 41 ± 8.0°, PRM was -19 ± 10.1°, ICM was 33 ± 8.8°, and EAS was -43 ± 6.4°. These fascicle directions were statistically different (p < 0.001). Pairwise comparisons among levator subdivisions showed angle differences of 60° between PVM and PRM, and 52° between ICM and PRM. An 84° difference existed between PVM and EAS. The smallest angle difference between levator divisions was between PVM and ICM 8°. The difference between PRM and EAS was 24°. All pairwise comparisons were significant (p < 0.001).

CONCLUSIONS

The null hypothesis that muscle fascicle inclinations are similar in the three subdivisions of the levator ani and the external anal sphincter was rejected. The largest difference in levator subdivision inclination, 60°, was found between the PVM and PRM.

Anatomy of the pubovisceral muscle origin: Macroscopic and microscopic findings within the injury zone

AIMS

The levator ani muscle (LA) injury associated with vaginal birth occurs in a characteristic site of injury on the inner surface of the pubic bone to the pubovisceral portion of the levator ani muscle's origin. This study investigated the gross and microscopic anatomy of the pubic origin of the LA in this region.

METHODS

Pubic origin of the levator ani muscle was examined in situ then harvested from nine female cadavers (35-98 years). A combination of targeted feature sampling and sequential sampling was used where each specimen was cut sequentially in approximately 5 mm thick slices apart in the area of known LA injury. Histological sections were stained with Masson's trichrome.

RESULTS

The pubovisceral origin is transparent and thin as it attaches tangentially to the pubic periosteum, with its morphology changing from medial to lateral regions. Medially, fibers of the thick muscle belly coalesce toward multiple narrow points of bony attachment for individual fascicles. In the central portion there is an aponeurosis and the distance between muscle and periosteum is wider (∼3 mm) than in the medial region. Laterally, the LA fibers attach to the levator arch where the transition from pubovisceral muscle to the iliococcygeal muscle occurs.

CONCLUSIONS

The morphology of the levator ani origin varies from the medial to lateral margin. The medial origin is a rather direct attachment of the muscle, while lateral origin is made through the levator arch.

Comparison of muscle fiber directions between different levator ani muscle subdivisions: in vivo MRI measurements in women

INTRODUCTION AND HYPOTHESIS

This study describes a technique to quantify muscle fascicle directions in the levator ani (LA) and tests the null hypothesis that the in vivo fascicle directions for each LA subdivision subtend the same parasagittal angle relative to a horizontal reference axis.

METHODS

Visible muscle fascicle direction in the each of the three LA muscle subdivisions, the pubovisceral (PVM; synonymous with pubococcygeal), puborectal (PRM), and iliococcygeal (ICM) muscles, as well as the external anal sphincter (EAS), were measured on 3-T sagittal MRI images in a convenience sample of 14 healthy women in whom muscle fascicles were visible. Mean ± standard deviation (SD) angle values relative to the horizontal were calculated for each muscle subdivision. Repeated measures ANOVA and post-hoc paired t tests were used to compare muscle groups.

RESULTS

Pubovisceral muscle fiber inclination was 41 ± 8.0°, PRM was -19 ± 10.1°, ICM was 33 ± 8.8°, and EAS was -43 ± 6.4°. These fascicle directions were statistically different (p < 0.001). Pairwise comparisons among levator subdivisions showed angle differences of 60° between PVM and PRM, and 52° between ICM and PRM. An 84° difference existed between PVM and EAS. The smallest angle difference between levator divisions was between PVM and ICM 8°. The difference between PRM and EAS was 24°. All pairwise comparisons were significant (p < 0.001).

CONCLUSIONS

The null hypothesis that muscle fascicle inclinations are similar in the three subdivisions of the levator ani and the external anal sphincter was rejected. The largest difference in levator subdivision inclination, 60°, was found between the PVM and PRM.

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.

A screening tool for clinically relevant urinary incontinence

AIMS

The Michigan Incontinence Symptom Index (M-ISI) is a validated measure for urinary incontinence. This study evaluates the M-ISI as a screening tool for clinically relevant urinary incontinence in a population-based sample of women.

METHODS

The Establishing the Prevalence of Incontinence (EPI) Study is a case-control, population-based study that enrolled women ages 35-64, with and without urinary incontinence. The M-ISI is a validated questionnaire with subdomains for stress and urgency urinary incontinence. Two hundred fourteen EPI subjects underwent a clinical evaluation and urodynamic testing to establish the presence and type of urinary incontinence, and also completed the M-ISI. The M-ISI scores were evaluated using receiver operating characteristic (ROC) curves to determine the optimal diagnostic threshold scores above which women were likely to have clinically relevant urinary incontinence.

RESULTS

The optimal M-ISI diagnostic threshold scores were determined to be ≥ 3 for the stress urinary incontinence subdomain (area under the curve of 0.79), ≥ 5 for the urgency urinary incontinence subdomain (area under the curve of 0.88), and ≥ 7 for the Total M-ISI score (area under the curve of 0.89). The sensitivity and specificity of the M-ISI questionnaire for stress, urgency, and total urinary incontinence were 77% and 73%, 86% and 76%, and 84% and 75%, respectively.

CONCLUSIONS

The M-ISI may be used to screen for clinically relevant urinary incontinence with high sensitivity and specificity among women ages 35-64. A brief, self-administered tool such as the M-ISI can help health care providers identify and manage women with urinary incontinence.

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.

The Michigan Incontinence Symptom Index (M-ISI): a clinical measure for type, severity, and bother related to urinary incontinence

AIMS

To develop a clinically relevant, easy to use, and validated instrument for assessing severity and bother related to urinary incontinence.

METHODS

Survey items were piloted and refined following psychometric principles in five separate patient cohorts. Patient and expert endorsement of items, factor analyses, Spearman rank correlations and response distributions were employed for item selection. Formal reliability and validity evaluation were conducted for the final questionnaire items.

RESULTS

Expert physicians and patient focus groups confirmed face and content validity for the measure. A 10-item measure called the Michigan Incontinence Symptom Index (M-ISI) was developed with two domains: a Total M-ISI Domain consisting of subdomains for stress urinary incontinence, urgency urinary incontinence, and pad use, and a Bother Domain. High construct validity was demonstrated with a Cronbach's alpha for the Total M-ISI Domain (items 1-8) of 0.90 and for the Bother Domain (items 9-10) of 0.82. Cronbach's alpha for the subdomains were all > 0.85. Construct validity, convergent and divergent validity, internal discriminant validity, and predictive validity were all robust. The minimally important difference for the measure was determined to be 4 points (out of 32) for the Total M-ISI Severity Domain, and 1-2 points (out of 8-12) for the individual subdomains.

CONCLUSIONS

The M-ISI is a parsimonious measure that has established reliability and validity on several levels and complements current clinical evaluative methods for patients with urinary incontinence.

Dynamic MRI evaluation of urethral hypermobility post-radical prostatectomy

AIMS

One postulated cause of post-prostatectomy incontinence is urethral and bladder neck hypermobility. The objective of this study was to determine the magnitude of anatomical differences of urethral and bladder neck position at rest and with valsalva in continent and incontinent men post-prostatectomy based on dynamic MRI.

METHODS

All subjects underwent a dynamic MRI protocol with valsalva and non-valsalva images and a standard urodynamic evaluation. MRI measurements were taken at rest and with valsalva, including (1) bladder neck to sacrococcygeal inferior pubic point line (SCIPP), (2) urethra to pubis, and (3) bulbar urethra to SCIPP. Data were analyzed in SAS using two-tailed t tests.

RESULTS

A total of 21 subjects (13 incontinent and 8 continent) had complete data and were included in the final analysis. The two groups had similar demographic characteristics. On MRI, there were no statistically significant differences in anatomic position of the bladder neck or urethra either at rest or with valsalva. The amount of hypermobility ranged from 0.8 to 2 mm in all measures. There were also no differences in the amount of hypermobility (position at rest minus position at valsalva) between groups.

CONCLUSIONS

We found no statistically significant differences in bladder neck and urethral position or mobility on dynamic MRI evaluation between continent and incontinent men status post-radical prostatectomy. A more complex mechanism for post-prostatectomy incontinence needs to be modeled in order to better understand the continence mechanism in this select group of men.

Understanding the dissemination of sacral neuromodulation

OBJECTIVES

To assess trends in the use of sacral neuromodulation and to measure the magnitude of variation in its use across geographic regions.

METHODS

We used the State Ambulatory Surgery Database (SASD) from 2002 to 2009 from Florida to identify patients implanted with a neuromodulator. Age- and gender-adjusted rates of implantation were calculated by year and by geographic region, defined by the Hospital Service Area. The coefficient of variation was estimated to quantify the magnitude of variation for different time periods.

RESULTS

Adjusted rates of sacral neuromodulation increased significantly from 1.1 per 100,000 population in 2002 to 10.4 per 100,000 population in 2009. The majority of cases were performed for overactive bladder. There was a very large amount of geographic variation in rates of these procedures as evidenced by the high coefficients of variation: 1.67 (2002 and 2003), 1.70 (2004 and 2005), 1.49 (2006 and 2007), and 1.05 (2008 and 2009).

CONCLUSIONS

Rates of sacral neuromodulation have increased dramatically over the past decade. However, these rates of utilization are highly variable across regions, with some regions performing large numbers of these procedures and other regions performing few to no procedures. This range in practice patterns may reflect medical uncertainty surrounding the role of this procedure.

Spontaneous pushing to prevent postpartum urinary incontinence: a randomized, controlled trial

INTRODUCTION AND HYPOTHESIS

The risk for urinary incontinence can be 2.6-fold greater in women after pregnancy and childbirth compared with their never-pregnant counterparts, with the incidence increasing with parity. We tested the hypothesis that the incidence of de novo postpartum urinary incontinence in primiparous women is reduced with the use of spontaneous pushing alone or in combination with perineal massage compared with women who experienced traditional directed pushing for second-stage management.

METHODS

This was a prospective clinical trial enrolling and randomizing 249 women into a four-group design: (1) routine care with coached or directed pushing, (2) spontaneous self-directed pushing, (3) prenatal perineal massage initiated in the third trimester, and (4) the combination of spontaneous pushing plus perineal massage. Self-report of incontinence was assessed using analysis of variance (ANOVA) and covariance (ANCOVA) models in 145 remaining women at 12 months postpartum using the Leakage Index, which is sensitive to minor leakage.

RESULTS

No statistical difference in the incidence of de novo postpartum incontinence was found based on method of pushing (spontaneous/directed) (P value = 0.57) or in combination with prenatal perineal massage (P value = 0.57). Fidelity to pushing treatment of type was assessed and between-groups crossover detected.

CONCLUSIONS

Spontaneous pushing did not reduce the incidence of postpartum incontinence experienced by women 1 year after their first birth due to high cross-over between randomization groups.

Post-reduction stress urinary incontinence rates in posterior versus anterior pelvic organ prolapse: a secondary analysis

INTRODUCTION/HYPOTHESIS

Stress incontinence with vaginal prolapse reduction is less common in women with posterior-predominant prolapse (rectocele) compared with those with anterior-predominant prolapse (cystocele).

METHODS

This was a secondary analysis of a cohort of prospectively enrolled women with symptomatic pelvic organ prolapse at or beyond the hymen and prolapse-reduced stress urinary incontinence (SUI) testing. Subjects were included if they had anterior- or posterior-predominant prolapse with at least a 1 cm difference in pelvic organ prolapse quantification (POP-Q) points Ba and Bp (N = 214). We evaluated the prevalence and risk factors of post-reduction SUI between the two groups.

RESULTS

Comparing posterior (n = 45) and anterior (n = 169) prolapse groups, we identified similar rates of post-reduction SUI (posterior: 6/45, 13.3 %; anterior:18/169, 10.7 %; p = 0.52) and SUI without reduction (posterior:4.4 %; anterior:11.2 %; p = 0.26). Maximum prolapse size was slightly larger in anterior than in posterior patients (+3.1 vs +2.0 cm beyond the hymen, p = 0.001), while a higher proportion of posterior subjects reported a prior hysterectomy (p = 0.04). Among posterior subjects, lower maximum urethral closure pressure values (MUCP; p = 0.02) were associated with post-reduction SUI. In contrast, among anterior-predominant prolapse, larger prolapse measured at POP-Q point Ba (p = 0.003) and maximum POP-Q measurement (p = 0.006) were each associated with higher rates of post-reduction SUI and were highly correlated with each other (R = 0.90).

CONCLUSIONS

We observed similar rates of post-reduction SUI in women with anterior- and posterior-predominant pelvic organ prolapse. Factors affecting the anterior and posterior prolapse groups differed, suggesting different mechanisms of continence protection. These findings suggest that reduction incontinence testing for operative planning would be as relevant to posterior-predominant prolapses as it is to anterior prolapse.

The relationship between pelvic organ prolapse, genital body image, and sexual health

AIMS

Pelvic organ prolapse involves physical changes to the genitals, potentially distressing to women. We hypothesized poorer genital body image in prolapsed women versus controls and that genital body image would correlate with sexual health.

METHODS

Seventy-four sexually active women, 13 with prolapse, 24 with surgically corrected prolapse, 37 without prolapse, completed the Genital Self Image Scale (GSIS-20), Body Esteem Scale (BES), and Female Sexual Function Index (FSFI).

RESULTS

In prolapsed women median GSIS-20 scores were 28/40, women with surgically corrected prolapse 32/40 and never prolapsed 34/40 (χ(2) = 9.6, P < 0.01). Post hoc analysis showed significant differences between prolapsed and never prolapsed groups (P < 0.05). After adjusting for BES, GSIS-20 correlated with overall FSFI (r = 0.384, P < 0.01), and its subscales of desire (r = 0.34, P < 0.05) and satisfaction (r = 0.41, P < 0.01).

CONCLUSIONS

Women with prolapse are at risk for poorer genital body image and reduced sexual health.

A subject-specific anisotropic visco-hyperelastic finite element model of female pelvic floor stress and strain during the second stage of labor

OBJECTIVES

To develop an improved model representation of the biomechanics of the levator muscles during the second stage of labor and to use a sensitivity analysis to explore the pathomechanics of levator muscle injury.

METHODS

A subject-specific finite element model of human pelvic floor and fetal head was developed based on in vivo MRI data of a fetal head and maternal pelvis. An anisotropic visco-hyperelastic constitutive model employed material parameters estimated from biaxial tests on pelvic floor tissues. Boundary conditions reflected both anatomic constraints and the curve of Carus. A short second stage of labor, scaled to 10 min, was then simulated using a single expulsive push made in the absence of levator co-contraction.

RESULTS

Large levator stresses occurred near the levator hiatus reaching 9 MPa at the pubovisceral muscle enthesis. The dominant principal stresses were located at, and aligned with, the edge of the hiatus. Muscle stretch bordering the levator hiatus was inhomogeneous: the average levator stretch was 3.55 with a high of 4.64 at the pubovisceral muscle enthesis. Decreasing perineal body stiffness by 40%, 50%, and 60% led to reductions in the maximum principal stretch ratio at the pubovisceral muscle enthesis of 8%, 13%, and 18%, respectively.

CONCLUSIONS

The pubovisceral muscle enthesis and the muscle near the perineal body are the regions of greatest strain thereby placing them at highest risk for stretch-related injury. Decreasing perineal body tissue stiffness significantly reduced tissue stress and strain, and therefore injury risk, in those regions.

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

INTRODUCTION AND HYPOTHESIS

This study assesses relative contributions of "midline defects" (widening of the vagina) and "paravaginal defects" (separation of the lateral vagina from the pelvic sidewall).

METHODS

Ten women with anterior predominant prolapse and ten with normal support underwent pelvic MR imaging. 3-D models of the anterior vaginal wall (AVW) were generated to determine locations of the lateral AVW margin, vaginal width, and apical position.

RESULTS

The lateral AVW margin was farther from its normal position in cases than controls throughout most of the vaginal length, most pronounced midvagina (effect sizes, 2.2-2.8). Vaginal widths differed in the midvagina with an effect size of 1.0. Strong correlations between apical and paravaginal support were evident in mid- and upper vagina (r = 0.77-0.93).

CONCLUSIONS

Changes in lateral AVW location were considerably greater than changes in vaginal width in cases vs controls, both in number of sites affected and effect sizes. These "paravaginal defects" are highly correlated with apical descent.