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.