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

INTRODUCTION AND HYPOTHESIS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

A novel measurement of pelvic floor cross-sectional area in older and younger women with and without prolapse

BACKGROUND

An increase in size of the aperture of the pelvis that must be spanned by pelvic floor support structures translates to an increase in the force on these structures. Prior studies have measured the bony dimensions of the pelvis, but the effect of changes in muscle bulk that may affect the size of this area are unknown.

OBJECTIVES

To develop a technique to evaluate the aperture size in the anterior pelvis at the level of the levator ani muscle attachments, and to identify age-related changes in women with and without prolapse.

MATERIALS AND METHODS

This was a technique development and pilot case-control study evaluating pelvic magnetic resonance imaging from 30 primiparous women from the Michigan Pelvic Floor Research Group MRI Data Base: 10 younger women with normal support, 10 older women with prolapse, and 10 older menopausal women without prolapse. Anterior pelvic area measurements were made in a plane that included the bilateral ischial spines and the inferior pubic point, approximating the level of the arcus tendineus fascia pelvis. Measurements of the anterior pelvic area, obturator internus muscles, and interspinous diameter were made by 5 independent raters from the Society of Gynecologic Surgeons Pelvic Anatomy Group who focused on developing pelvic imaging techniques, and evaluating interrater reliability. Demographic characteristics were compared across groups of interest using the Wilcoxon rank sum test, χ2, or Fisher exact test where appropriate. Multiple linear regression models were created to identify independent predictors of anterior pelvic area.

RESULTS

Per the study design, groups differed in age and prolapse stage. There were no differences in race, height, body mass index, gravidity, or parity. Patients with prolapse had a significantly longer interspinous diameter, and more major (>50% of the muscle) levator ani defects when compared to both older and younger women without prolapse. Interrater reliability was high for all measurements (intraclass correlation coefficient = 0.96). The anterior pelvic area (cm2) was significantly larger in older women with prolapse compared to older (60 ± 5.1 vs 53 ± 4.9, P = .004) and younger (60 ± 5.1 vs 52 ± 4.6, P = .001) women with normal support. The younger and older women with normal support did not differ in anterior pelvic area (52 ± 4.6 vs 53 ± 4.9, P = .99). After adjusting for race and body mass index, increased anterior pelvic area was significantly associated with the following: being an older woman with prolapse (β = 6.61 cm2, P = .004), and interspinous diameter (β = 4.52 cm2, P = .004).

CONCLUSION

Older women with prolapse had the largest anterior area, suggesting that the anterior pelvic area is a novel measure to consider when evaluating women with prolapse. Interspinous diameter, and being an older woman with prolapse, were associated with a larger anterior pelvic area. This suggests that reduced obturator internus muscle size with age may not be the primary factor in determining anterior pelvic area, but that pelvic dimensions such as interspinous diameter could play a role. The measurements were highly repeatable. The high intraclass correlation coefficient indicates that all raters were able to successfully learn the imaging software and to perform measurements with high reproducibility.

Are bony pelvis dimensions associated with levator ani defects? A case-control study

INTRODUCTION AND HYPOTHESIS

Bony pelvis dimensions have been shown to differ in women with and without pelvic floor dysfunction. The goal of this study was to determine whether bony pelvis dimensions are different when comparing women with severe bilateral levator ani defects (LAD) with those with normal muscles.

METHODS

This is a secondary analysis of a case-control study comparing women with and those without pelvic organ prolapse. Subjects underwent pelvic organ prolapse quantification (POP-Q) examination and were classified as either having prolapse or being normal. All underwent pelvic magnetic resonance imaging (MRI). Levator defects were assessed based on the muscles' appearance on imaging and subjects were stratified into two groups--women with normal muscles (n = 99) and women with severe bilateral LAD (n = 50). Bony pelvis dimensions were measured via MRI pelvimetry. The subpubic angle, interspinous and intertuberous diameters, and the sacrococcygeal joint-to-infrapubic point (SCIPP) lengths were compared.

RESULTS

Both groups had similar demographics. The SCIPP length was 2.5 % (3 mm) shorter in women with severe LAD than in those without defects (P = 0.02). The SCIPP measured 4 % (5 mm) less in women with prolapse and severe LAD than in subjects with prolapse but normal muscles (P = 0.01). Logistic regression identified SCIPP length and history of forceps delivery as being independent predictors of severe bilateral LAD.

CONCLUSIONS

Severe bilateral LAD are associated with shorter SCIPP length and forceps-assisted vaginal delivery.

Racial differences in self-reported healthcare seeking and treatment for urinary incontinence in community-dwelling women from the EPI Study

AIMS

Objectives of this study are: (1) to examine the prevalence of healthcare seeking among black and white women with self-reported urinary incontinence (UI), (2) to investigate barriers to treatment for incontinence, and (3) To investigate commonly used therapeutic modalities for UI.

METHODS

This is a planned secondary analysis of responses from 2,812 black and white community-dwelling women living in southeastern Michigan, aged 35-64 years, who completed a telephone interview concerning UI, healthcare-seeking behaviors and management strategies. The study population was 571 subjects (278 black, 293 white) who self-identified as having urinary incontinence.

RESULTS

Of these women with UI, 51% sought healthcare with no statistically significant difference between the two races (53% black, 50.6% white, P = 0.64). In multivariate logistic regression analysis, a higher likelihood of seeking healthcare was associated with increased age, body mass index lower than 30  kg/m(2) , prior surgery for UI, having regular pelvic exams, having a doctor, and worsening severity of UI. There was no significant association between hypothesized barriers to care seeking and race. Almost 95% of the subjects identified lack of knowledge of available treatments as one barrier. Black and white women were similar in percentage use of medications and some self-care strategies, for example, pad wearing and bathroom mapping, but black women were significantly more likely to restrict fluid intake than white women and marginally less likely to perform Kegels.

CONCLUSIONS

Black and white women seek healthcare for UI at similar, low rates. Improved patient-doctor relationships and public education may foster healthcare seeking behavior.

Assessment of lung-cancer mortality reduction from CT Screening

BACKGROUND

CT screening has been shown to increase lung cancer curability and we now assess the corresponding reduction in lung cancer mortality.

METHODS

Lung-cancer mortality in a cohort of 7995 smokers who underwent CT screening for lung cancer in New York State (NYS) was compared with two unscreened cohorts (CPS-II and CARET). The standardized mortality ratio (SMR) of observed to expected lung cancer deaths for NYS was jointly adjusted for age, sex, and smoking history. As more current NYS smokers might have quit as a result of the screening, thus reducing deaths from lung cancer, another analysis was restricted to those participants smoking at entry and still smoking 6 years later.

RESULTS

The SMR was 64/99.8=0.64 (P = 0.84 × 10⁻⁴) and 28/77.6=0.36 (P = 0.83 × 10⁻¹⁰), showing a significant reduction in deaths from lung cancer of 36% and 64% for CPS-II and CARET, respectively. Considering participants who were smoking at entry and still smoking 6 years later, the SMR using CPS-II rates was 29/49.1 = 0.59 (P = 0.001) and using CARET rates it was 21/57.4 = 0.37 (P = 0.31 × 10⁻⁷).

CONCLUSIONS

CT screening significantly reduces lung-cancer mortality.

Correlation between levator ani muscle injuries on magnetic resonance imaging and fecal incontinence, pelvic organ prolapse, and urinary incontinence in primiparous women

OBJECTIVE

The objective of the study was to correlate the presence of major levator ani muscle (LAM) injuries on magnetic resonance imaging (MRI) with fecal incontinence (FI), pelvic organ prolapse (POP), and urinary incontinence (UI) in primiparous women 6-12 months postpartum.

STUDY DESIGN

A published scoring system was used to characterize LAM injuries on MRI dichotomously (MRI negative, no/mild vs MRI positive, major).

RESULTS

Major LAM injuries were observed in 17 of 89 (19.1%) women who delivered vaginally with external anal sphincter (EAS) injuries, 3 of 88 (3.5%) who delivered vaginally without EAS injury, and 0 of 29 (0%) who delivered by cesarean section before labor (P=.0005). Among women with EAS injuries, those with major LAM injuries trended toward more FI, 35.3% vs 16.7% (P=.10) and POP, 35.3% vs 15.5% (P=.09), but not UI (P=1.0).

CONCLUSION

These data support the growing body of literature suggesting that both EAS and LAM are important for fecal continence and that multiple injuries contribute to pelvic floor dysfunction.

Heterogeneity in Anatomic Outcome of Sacrospinous Ligament Fixation for Prolapse

OBJECTIVE

To explore why failure rates vary so much between published reports of sacrospinous ligament fixation to correct pelvic organ prolapse and what the potential sources of heterogeneity may be.

DATA SOURCES

MEDLINE was queried for studies between 1966 and 2005 that included the term "sacrospinous."

METHODS OF STUDY SELECTION

One-hundred eighty-seven studies were reviewed. Studies were selected if they 1) involved a surgical procedure performed unilaterally with a posterior or apical vaginal incision and approach to the ligament; 2) reported objective outcomes with a classification system (Baden-Walker, pelvic organ prolapse quantification) over a defined follow-up period; and 3) were published in English, French, or German. Random effects meta-analyses were conducted for both objective and subjective measures of failure.

TABULATION, INTEGRATION, AND RESULTS

Seventeen cohorts met the selection criteria, and the Baden-Walker vaginal profile or a close variation suitable for meta-analysis was used in 10 of them. Variability in failure rates was observed depending on site of and grade of vaginal support (P<.05). The anterior compartment was the most common site of failure for any given grade. This was most striking when the criterion for failure was grade 1 (40.1% anterior, 11.0% apical, 18.2% posterior) or grade 2 prolapse (21.3% anterior, 7.2% apical, 6.3% posterior). Areas of vaginal support were more equally affected when the criterion for failure was grade 3 prolapse (3.7% anterior, 2.7% apical, 2.3% posterior). Among cohorts using grade 2 prolapse as the criterion for objective failure, the pooled measure of failure to relieve symptoms was 10.3% (95% confidence interval 4.4-16.2%) and to provide patient satisfaction was 13.0% (95% confidence interval 7.4-18.6%).

CONCLUSION

The variation in published failure rates after sacrospinous ligament fixation is, in part, accounted for by differences in how anatomical outcomes are evaluated and which compartment of vaginal support is being considered. Failure rates are highest in the anterior compartment.

Racial differences in the structure and function of the stress urinary continence mechanism

OBJECTIVE

To compare the structure and function of the urethral sphincter and the urethral support in nulliparous black and white women.

METHODS

Eighteen black women (mean age 28.1 years) and 17 white women (mean age 31.3 years) completed this cross-sectional study. The following assessments were made: urethral function using multichannel cystometrics and urethral pressure profilometry, pelvic muscle strength using an instrumented speculum, urethral mobility using the cotton-swab test and perineal ultrasound, and pelvic muscle bulk using magnetic resonance imaging.

RESULTS

Black women demonstrated a 29% higher average urethral closure pressure during a maximum pelvic muscle contraction (154 cm H(2)O versus 119 cm H(2)O in the white subjects; P =.008). Although not statistically significant, black women had a 14% higher maximum urethral closure pressure at rest (108 cm H(2)O versus 95 cm H(2)O; P =.23) and a 21% larger urethral volume (4818 mm(3) versus 3977 mm(3); P =.06). In addition, there was a 36% greater vesical neck mobility measured with the cotton-swab test (blacks 49 degrees versus whites 36 degrees; P =.02) and a 42% difference in ultrasonically measured vesical neck mobility during a maximum Valsalva effort (blacks = -17 mm versus whites -12 mm; P =.08).

CONCLUSION

Functional and morphologic differences exist in the urethral sphincteric and support system of nulliparous black and white women.

Differential effects of cough, valsalva, and continence status on vesical neck movement

OBJECTIVE

We tested the null hypothesis that vesical neck descent is the same during a cough and during a Valsalva maneuver. We also tested the secondary null hypothesis that differences in vesical neck mobility would be independent of parity and continence status.

METHODS

Three groups were included: 17 nulliparous continent (31.3 +/- 5.6; range 22-42 years), 18 primiparous continent (30.4 +/- 4.3; 24-43), and 23 primiparous stress-incontinent (31.9 +/- 3.9; 25-38) women. Measures of vesical neck position at rest and during displacement were obtained by ultrasound. Abdominal pressures were recorded simultaneously using an intravaginal microtransducer catheter. To control for differing abdominal pressures, the stiffness of the vesical neck support was calculated by dividing the pressure exerted during a particular effort by the urethral descent during that effort.

RESULTS

The primiparous stress-incontinent women displayed similar vesical neck mobility during a cough effort and during a Valsalva maneuver (13.8 mm compared with 14.8 mm; P =.49). The nulliparous continent women (8.2 mm compared with 12.4 mm; P =. 001) and the primiparous continent women (9.9 mm compared with 14.5 mm; P =.002) displayed less mobility during a cough than during a Valsalva maneuver despite greater abdominal pressure during cough. The nulliparas displayed greater pelvic floor stiffness during a cough compared with the continent and incontinent primiparas (22.7, 15.5, 12.2 cm H(2)O/mm, respectively; P =.001).

CONCLUSION

There are quantifiable differences in vesical neck mobility during a cough and Valsalva maneuver in continent women. This difference is lost in the primiparous stress-incontinent women.

Sonographic evaluation of the bladder neck in continent and stress-incontinent women

OBJECTIVE

To evaluate a new sonographic method to measure depth and width of proximal urethral dilation during coughing and Valsalva maneuver and to report its use in a group of stress-incontinent and continent women.

METHODS

Fifty-eight women were evaluated, 30 with and 28 without stress incontinence proven urodynamically, with a bladder volume of 300 mL and the subjects upright. Urethral pressure profiles at rest were performed with a 10 French microtip pressure catheter. Bladder neck dilation and descent were assessed by perineal ultrasound (5 MHz curved linear array transducer) with the help of ultrasound contrast medium (galactose suspension-Echovist-300), whereas abdominal pressure was assessed with an intrarectal balloon catheter. Statistical analysis used the nonparametric Mann-Whitney test.

RESULTS

The depth and diameter of urethral dilation could be measured in all women. During Valsalva, all 30 incontinent women exhibited urethral dilation. One incontinent woman showed dilation only while performing a Valsalva maneuver, not during coughing. In the continent group, 12 women presented dilation during Valsalva and six during coughing. In continent women, dilation was visible only in those who were parous. Nulliparous women did not have dilation during Valsalva or coughing. Bladder neck descent was visible in continent and incontinent women.

CONCLUSION

This method permits quantification of depth and diameter of bladder neck dilation, showing that both incontinent and continent women might have bladder neck dilation and that urinary continence can be established at different locations along the urethra in different women. Parity seems to be a main prerequisite for a proximal urethral defect with bladder neck dilation.

Quantification of cough-related urine loss using the paper towel test

OBJECTIVE

To develop and test a simple and rapid method for quantifying the urine loss resulting from three deep coughs using an ordinary brown paper towel.

METHODS

A brown paper towel is held lightly against the perineum during three single coughs performed in the upright stance. The resulting wetted area was calculated using simple geometry; if desired, leakage volume can be interpolated from a calibration curve, which demonstrates the relationship between wetted area (cm2) and volume (mL) of leakage. Four bench tests of the method were performed. In addition, the test-retest reliability of the method was evaluated in eight elderly women with mild stress urinary incontinence, a sample size adequate to detect a 1-mL difference with 80% power.

RESULTS

The smallest measurable quantity of fluid resulted in a wetted area of 0.04 cm2 (equivalent to 0.2 microl). For leakage volumes up to 6 mL, the regression showed that each 1 mL of fluid volume resulted in an average 25.4 cm2 increase in wetted area (coefficient of determination: 0.97). In eight women with stress incontinence 95% of within- and across-visit comparisons of urine loss were within 1 mL.

CONCLUSION

The paper towel test is a simple and reliable measure providing immediate visual and quantitative feedback of cough-related urine loss typical of mild-to-moderate stress urinary incontinence.

Effect of pelvic muscle exercise on transient incontinence during pregnancy and after birth

OBJECTIVE

To test the effect of pelvic muscle exercise on postpartum symptoms of stress urinary incontinence and pelvic muscle strength in primigravidas during pregnancy and postpartum.

METHODS

A prospective trial randomized women into treatment (standardized instruction in pelvic muscle exercise) or control (routine care with no systematic pelvic muscle exercise instruction). Urinary incontinence symptoms were measured by questionnaire. Pelvic muscle strength was quantified by an instrumented gynecologic speculum. Time points were 20 and 35 weeks' gestation and 6 weeks, 6 months, and 12 months postpartum.

RESULTS

Outcomes are reported for 46 women with vaginal or cesarean birth and for a subsample of 37 women with vaginal birth. Longitudinal analyses are reported for cases with complete data across time points. Diminished urinary incontinence symptoms were seen in the treatment group, with significant treatment effects demonstrated at 35 weeks' gestation (F [1,43] = 4.36, P = .043), 6 weeks postpartum (F [1,43] = 4.94, P = .032), and 6 months postpartum (F [1,43] = 4.29, P = .044). A repeated measures analysis of variance showed a significant interaction between time and treatment for urinary incontinence (F [4, 41] = 2.83, P = .037). A significant effect of initial pelvic muscle strength was demonstrated; ie, pelvic muscle strength at 20 weeks' gestation predicted significantly 12-months postpartum strength (F [1, 13] = 8.12, P = .014). Group differences in pelvic muscle strength were observed (the treatment group had greater strength at 6 weeks and at 6 months postpartum than did controls), but these differences were not statistically significant.

CONCLUSION

Practice of pelvic muscle exercise by primiparas results in fewer urinary incontinence symptoms during late pregnancy and postpartum.

Size of the urogenital hiatus in the levator ani muscles in normal women and women with pelvic organ prolapse

OBJECTIVE

Compare urogenital hiatus size in normal women and women with pelvic organ prolapse.

METHODS

The sagittal and transverse urogenital hiatus diameters were measured and hiatus area calculated in 300 women whose support was scored using a modified Baden system.

RESULTS

In women with normal support and without prior surgery, hiatus area was 5.4 cm2 (+/-1.71 standard deviation [SD], n = 197). In women with uncorrected clinical prolapse (grade 2-3), the area of the hiatus was enlarged (9.6 cm2 +/- 3.97, n = 34, P < .05) and became larger with progressive prolapse (grade 0, 5.4 cm2 +/- 1.71, n = 197; grade 1, 7.3 cm2 +/- 1.91, n = 27; grade 2, 8.3 cm2 +/- 2.45, n = 18; grade 3, 11.0 cm2 +/- 4.90, n = 16). When matched for age and parity, prolapse patients had a larger hiatus than normal women. Women with recurrent prolapse had a larger hiatus than cured women (13.3 cm2 +/- 3.86, n = 8 compared with 8.1 cm2 +/- 2.44, n = 16, P < .05) or women with recurrence after one operation (8.9 cm2 +/- 1.77, n = 18, P < .05). Hiatus size in patients surgically cured (8.3 cm2 +/- 2.44, n = 16) did not return to normal (5.4 cm2 +/- 1.71, n = 197, P < .05). Increasing area of the hiatus was correlated with an increase in anterior-posterior diameter (r2 = 0.9, P < .05), was less attributable to increased transverse diameter (r2 = 0.6, P < .05), and was not related to thickness of the perineal body (r2 = 0.0, P > .05).

CONCLUSION

Increasing pelvic organ prolapse is associated with increasing urogenital hiatus size; the hiatus is larger after several failed operations than after successful surgery or single failure.

Intraurethral ultrasound correlated with urethral histology

OBJECTIVE

To examine the anatomic identity of sonographically visible sphincteric structures of the female urethra.

METHODS

The urethra, urinary bladder, and vagina were removed from 11 fresh female cadavers and placed in a water bath. Intraurethral ultrasound was performed with a 360 degrees-rotating 7.5-MHz ultrasound probe. Afterward, the specimens were fixed and cross sections were made transverse to the urethral axis at 5-mm intervals. Corresponding ultrasonograms and histologic images were matched and depicted simultaneously side by side. The anatomic identity of sonographically visible structures was determined by histologic examination and thickness of the longitudinal smooth urethral sphincter measured.

RESULTS

Structures visible sonographically were the striated and smooth urethral sphincter muscle layers, vagina, and blood vessels with diameters exceeding 0.2 mm. The longitudinal smooth muscle layer appeared as a well-defined internal hypoechoic ring. The outer circular smooth muscle layers and the striated muscle layers were a more irregular and hyperechoic zone. The circular smooth muscle layers and the striated sphincter muscle layers could not always be differentiated easily. With formalin fixation, tissue shrinkage resulted in a smaller thickness of the longitudinal smooth muscle measured on the histologic specimen.

CONCLUSION

With intraurethral ultrasound, the longitudinal smooth muscle layer appears as a well-defined and measurable hypoechoic ring. The region of the circular smooth muscle and the striated muscle emerges as a hyperechoic and less definable outer zone.

Internal and external anal sphincter anatomy as it relates to midline obstetric lacerations

OBJECTIVE

To examine the anatomy of the internal and external anal sphincters in the area of midline obstetric lacerations, to gain insight into sphincter damage and repair.

METHODS

The length, craniocaudal extent, and overlap of the internal and external anal sphincters in the perineal body were measured in 17 cadavers. Further anatomic observations were made in four sets of whole pelvis cross-sections taken in the sagittal, coronal, and transverse planes. During the repair of 20 acute fourth-degree lacerations, observations were made to determine the internal sphincter visibility following birth.

RESULTS

The external and internal and sphincters overlap by 17.0 mm (standard deviation [SD] 6.9), with the internal sphincter lying between the external sphincter and the anal canal. The internal sphincter extends an additional 12.2 mm (SD 5.9) cranial to the proximal extent of the external sphincter, whereas the caudal margin of the internal sphincter lies 3.7 mm (SD 7.2) cranial to the distal margin of the external sphincter. In pregnant women who sustained a fourth-degree laceration, we found that the internal sphincter can be identified as a rubbery white layer adjacent to the anal submucosa lying between the external sphincter and the anal canal.

CONCLUSION

The internal anal sphincter lies between the anal mucosa and the external anal sphincter and extends more than a centimeter above the cranial margin of the external sphincter, a region where it is disrupted when a fourth-degree obstetric laceration has occurred.

Pelvic organ prolapse in young women

OBJECTIVE

To determine differences in the characteristics and type of genital prolapse in young women compared with older women.

METHODS

A retrospective analysis was performed, identifying 647 women who underwent surgical repair of various types of genital prolapse for the years 1979-1991. One hundred ninety-one patients met our inclusion criteria, having well-documented genital prolapse to or beyond the hymen. Patients were stratified into two age groups, those over 35 years and those 35 or younger. The patients were compared regarding "complexity" of prolapse (ie, the total number of deficient sites per patient), grade of prolapse, parity and coexistent medical conditions.

RESULTS

During the study period, 27 young women (mean age +/- standard deviation [SD] 30.3 +/- 3.4 years) and 164 older women (mean age +/- SD 60.6 +/- 11.9 years) met our criteria. Young women were more likely than older women to have 1) potential predisposing medical conditions (congenital anomalies or neurologic or connective tissue diseases) (22.2% versus 6.7%, P < .05), 2) lower mean parity (2.8 versus 3.4, P < .05), 3) only one site of prolapse (56% versus 23%, P < .01), and 4) lower grade of prolapse (33% versus 87% grade 3 or higher, P < .001).

CONCLUSION

Young patients undergoing surgery for genital prolapse were more likely to have lower parity and single-site and lower-grade prolapse. A higher than expected prevalence of congenital anomalies, as well as rheumatologic and neurologic diseases in the younger women is intriguing, but further study is necessary before these conditions can be implicated in the genesis of genital prolapse.

Changes in vesical neck mobility following vaginal delivery

OBJECTIVE

To assess changes in urethral movement during the Valsalva maneuver and pelvic floor muscle contraction following vaginal delivery.

METHODS

In a prospective repeated-measures study, 25 primigravidas, 20 multiparas, and ten women who were to have elective cesarean delivery were examined sonographically at 36-42 weeks of pregnancy and 6-10 weeks after delivery. Vesical neck position at rest and excursion during Valsalva maneuver and maximum pelvic muscle contraction were measured with perineal ultrasound. Data about resting bladder neck position and bladder neck elevation at contraction were compared with findings in age-matched nulligravid volunteers.

RESULTS

The bladder neck was significantly lower at rest in women after vaginal delivery than in those who had an elective cesarean delivery and in nulligravid controls. Bladder neck mobility had increased during the Valsalva maneuver in 16 of 25 primigravidas and 15 of 20 multiparas 6-10 weeks after vaginal delivery. The ability to elevate the vesical neck during pelvic muscle contraction was decreased in six of 25 primigravidas and in two of 20 multiparas 6-10 weeks after birth. Two women, one primigravid and one para 2 (with a previous elective cesarean delivery), both of whom had forceps delivery, completely lost the ability to contract voluntarily the pelvic floor muscles.

CONCLUSION

Vaginal delivery alters vesical neck descent during the Valsalva maneuver, and the ability of the pelvic muscles to elevate the urethra in some women.

Magnetic resonance imaging anatomy of the female urethra: a direct histologic comparison

OBJECTIVE

To define the urethral structures visible on magnetic resonance imaging (MRI) relevant to stress urinary incontinence.

METHODS

The urethra and surrounding tissues were harvested from 13 female cadavers (ages 21-81) and fixed in 10% buffered formalin. High-resolution T1- and T2-weighted images were obtained at 1.5 tesla. Mallory trichrome-stained histologic sections were prepared in corresponding planes from the cadaveric specimens. Immunohistologic stains for smooth muscle (actin) and vascular endothelium (CD-34 and factor VIII) were obtained on two specimens. Histology and MRI were compared using side-by-side correlation of projected images and by superimposing projected images. Comparison was also made to a non-cadaveric urethral MRI of a 29-year-old woman and to the MRI of another specimen imaged pre- and post-fixation.

RESULTS

Distinct layers of the cadaveric urethra were seen best on proton density and T2-weighted images. From the center to the periphery, a series of concentric rings were visible: an inner bright ring, the mucosa; a dark ring, the submucosa; an outer bright ring, the smooth muscle of the urethra in a loose connective tissue matrix; and a peripheral dark ring, the striated urogenital sphincter muscle of the urethra in dense connective tissue. No significant alterations were caused by fixation. These cadaveric images matched the non-cadaveric MRI of the 29-year-old woman.

CONCLUSION

The internal urethral anatomy visible on high-resolution MRI can be identified and confirmed histologically, and these findings may form the basis for future anatomic investigation of stress urinary incontinence and other urethral abnormalities.