Janis M. Miller

Comparison of levator ani muscle defects and function in women with and without pelvic organ prolapse.

BACKGROUND: To compare levator ani defects and pelvic floor function among women with prolapse and controls. METHODS: Levator ani structure and function were measured in a case–control study with group matching for age, race, and hysterectomy status among 151 women with prolapse (cases) and 135 controls with normal support (controls) determined by pelvic organ prolapse quantification examination. Magnetic resonance imaging was used to determine whether there were “major” (more than half missing), “minor” (less than half of the muscle missing), or no defects in the levator ani muscles. Vaginal closure force at rest and during maximal pelvic muscle contraction was measured with an instrumented vaginal speculum. RESULTS: Cases were more likely to have major levator ani defects than controls (55% compared with 16%), with an adjusted odds ratio of 7.3 (95% confidence interval 3.9–13.6, P<.001) but equally likely to have minor defects (16% compared with 22%). Of women who reported delivery by forceps, 53% had major defects compared with 28% for the nonforceps women, adjusted odds ratio 3.4 (95% confidence interval 1.95–5.78). Women with prolapse generated less vaginal closure force during pelvic muscle contraction than controls (2.0 Newtons compared with 3.2 Newtons P<.001), whereas those with defects generated less force than women without defects (2.0 Newtons compared with 3.1 Newtons, P<.001). The genital hiatus was 50% longer in cases than controls (4.7±1.4 cm compared with 3.1±1.0 cm, P<.001). CONCLUSION: Women with prolapse more often have defects in the levator ani and generate less vaginal closure force during a maximal contraction than controls. LEVEL OF EVIDENCE: II

Obstetric factors associated with levator ani muscle injury after vaginal birth.

OBJECTIVE: To identify obstetric factors associated with development of levator ani injury after vaginal birth. METHODS: Magnetic resonance images were taken of the pelvic floor of 160 women 9 to 12 months after first term vaginal delivery. Half the women had de novo stress incontinence and half were continent controls. Abnormalities of the pubovisceral portion were identified on magnetic resonance as present or absent. Defect severity was further scored in each muscle from 0 (no defect) to 3 (complete muscle loss). A summed score for the 2 sides (0 to 6) was assigned and grouped as minor (0–3) or major (4–6). Obstetric details were collected. The association between obstetric variables and muscle injury were analyzed using Fisher exact test and t tests. RESULTS: The following increased odds ratios for levator defect were found: forceps use 14.7 (95% confidence interval [CI] 4.9–44.3), anal sphincter rupture 8.1 (95% CI 3.3–19.5) and episiotomy 3.1 (95% CI 1.4–7.2) but not vacuum delivery 0.9 (95% CI 0.19–4.3), epidural use 0.9 (95% CI 0.4–2.0), or oxytocin use 0.8 (95% CI 0.3–1.8). Women with levator injury were 3.5 years older and had a 78-minute longer second stage of labor. Differences in gestational age, birth weight, and head circumference were not statistically significant. A major defect in the pubovisceral muscle was seen in 22 women and a minor defect in 7 women. CONCLUSION: Injuries to the levator ani muscles in women after their first vaginal delivery are associated with several obstetric factors indicating difficult vaginal birth and with older age. LEVEL OF EVIDENCE: II-3

A pelvic muscle precontraction can reduce cough-related urine loss in selected women with mild SUI

OBJECTIVES: To test the hypothesis that selected older women with mild‐to‐moderate stress urinary incontinence (SUI) can learn to demonstrate significantly reduced urine loss in 1 week by intentionally contracting the pelvic floor muscles before and during a cough (a skill we have termed “The Knack”).

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.

Stress Urinary Incontinence: Relative Importance of Urethral Support and Urethral Closure Pressure

PURPOSEnTreatment strategies for stress incontinence are based on the concept that urethral mobility is the predominant causal factor with sphincter function a secondary contributor. To our knowledge the relative importance of these 2 factors has not been assessed in properly controlled studies.nnnMATERIALS AND METHODSnThe Research on Stress Incontinence Etiology project is a case-control study that compared 103 women with stress incontinence and 108 asymptomatic controls in groups matched for age, race, parity and hysterectomy. Urethral closure pressure, urethral and pelvic organ support, levator ani muscle function and intravesical pressure were measured and analyzed using logistic regression and multivariable modeling.nnnRESULTSnMean +/- SD maximal urethral closure pressure was 42% lower in cases (40.8 +/- 17.1 vs 70.2 +/- 22.4 cm H(2)O, d = 1.47). Lesser effect sizes were seen for support parameters, including resting urethral axis and urethrovaginal support (d = 0.41 and 0.50, respectively). Other pelvic floor parameters, including genital hiatus size and urethral axis during muscle contraction (d = 0.60 and 0.58, respectively), differed but levator strength and levator defect status did not. Maximum cough pressure, which is an assessment of stress on the continence mechanism, was also different (d = 0.43). After adjusting for body mass index the maximal urethral closure pressure alone correctly classified 50% of cases. Adding the best predictors for urethrovaginal support and cough strength to the model added 11% of predictive ability.nnnCONCLUSIONSnThe finding that maximal urethral closure pressure and not urethral support is the factor most strongly associated with stress incontinence implies that improving urethral function may have therapeutic promise.

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 H2O/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.

Pelvic Floor Muscle Contraction During a Cough and Decreased Vesical Neck Mobility

Objective To test the hypothesis that a voluntary pelvic muscle contraction initiated in preparation for a cough, a maneuver we call the Knack, significantly reduces vesical neck displacement. Methods A convenience sample of 22 women consisted of 11 young, continent nulliparas (mean age [± standard deviation] 24.8 ± 7.0 years) and 11 older, incontinent paras (mean age [±SD] 66.9 ± 3.9 years). With the use of perineal ultrasound, we quantified vesical neck displacement at rest and during coughs using caliper tracing and a coordinate system. The subjects coughed with and without voluntary pelvic floor muscle contraction. Results Vesical neck mobility during coughs was significantly decreased when voluntary contraction was used: from a median (range) of 5.4 (20.0) mm without volitional contraction to 2.9 (18.3) mm with volitional contraction (P < .001). The younger women demonstrated a median (range) decrease in excursion from 4.6 (19.5) to 0.0 (17.0) mm (P = .007), and the older incontinent women demonstrated a median (range) decrease from 6.2 (10.0) to 3.5 (15.4) mm (P = .003). At rest, the median vesical neck position in the group of older incontinent women was significantly further dorsocaudal (P = .001) than in the younger women. Conclusion A pelvic floor muscle contraction in preparation for, and throughout, a cough can augment proximal urethra support during stress, thereby reducing the amount of dorsocaudal displacement.

Graphic integration of causal factors of pelvic floor disorders : an integrated life span model

There is growing interest in causal factors for pelvic floor disorders. These conditions include pelvic organ prolapse and urinary and fecal incontinence and are affected by a myriad of factors that increase occurrence of symptomatic disease. Unraveling the complex causal network of genetic factors, birth-induced injury, connective tissue aging, lifestyle and comorbid factors is challenging. We describe a graphical tool to integrate the factors affecting pelvic floor disorders. It plots pelvic floor function in 3 major life phases: (1) development of functional reserve during an individuals growth, (2) variations in the amount of injury and potential recovery that occur during and after vaginal birth, and (3) deterioration that occurs with advancing age. This graphical tool accounts for changes in different phases to be integrated to form a disease model to help assess the overlap of different causal factors.

Establishing the Prevalence of Incontinence Study: Racial Differences in Women's Patterns of Urinary Incontinence

PURPOSEnWe examine racial differences in urinary incontinence prevalence, frequency, quantity, type, and risk factors in a population based sample of community dwelling black and white women.nnnMATERIALS AND METHODSnWomen 35 to 64 years old were sampled from telephone records from 3 southeast Michigan counties. Women self-identifying as black or white race completed a telephone interview that assessed demographics, health history, lifestyle factors and urinary incontinence experience. Statistical analysis included descriptive statistics, factor analysis and multivariable logistic regression to determine adjusted odds of urinary incontinence. Estimates were weighted to reflect probability and nonresponse characteristics of the sample, and to increase generalizability of the findings.nnnRESULTSnInterviews were completed by 1,922 black and 892 white women (response rate = 69%). The overall prevalence of urinary incontinence was 26.5%. By race, urinary incontinence prevalence was 14.6% for black women and 33.1% for white women (p <0.001). Among incontinent women there was no difference by race in the frequency of urinary incontinence. However, black women reported more urine loss per episode (p <0.05). A larger proportion of white women with incontinence (39.2%) reported symptoms of pure stress incontinence compared to black women (25.0%), whereas a larger proportion of black women (23.8%) reported symptoms of pure urge incontinence compared to white women (11.0%). Risk factors for urinary incontinence were generally similar for white and black women.nnnCONCLUSIONSnIn this population based study we observed racial differences in prevalence, quantity and type of urinary incontinence. Frequency of and risk factors for urinary incontinence were generally similar for white and black women.

Vaginal birth and de novo stress incontinence: Relative contributions of urethral dysfunction and mobility

OBJECTIVE: To evaluate the relative contributions of urethral mobility and urethral function to stress incontinence. METHODS: This was a case-control study with group matching. Eighty primiparous women with self-reported new stress incontinence 9–12 months postpartum were compared with 80 primiparous continent controls to identify impairments specific to stress incontinence. Eighty nulliparous continent controls were evaluated as a comparison group to allow us to determine birth-related changes not associated with stress incontinence. Urethral function was measured with urethral profilometry, and vesical neck mobility was assessed with ultrasound and cotton swab test. Urethral sphincter anatomy and mobility were evaluated using magnetic resonance imaging. The associations among urethral closure pressure, vesical neck movement, and incontinence were explored using logistic regression. RESULTS: Urethral closure pressure (±standard deviation) in primiparous incontinent women (62.9±25.2 cm H20) was lower than in primiparous continent women (83.9±21.0, P<.001; effect size d=0.91) who were similar to nulliparous women (90.3±25.0, P=.091). Vesical neck movement measured during cough with ultrasonography was the mobility measure most associated with stress incontinence; 15.6±6.2 mm in incontinent women compared with 10.9±6.2 in primiparous continent women (P<.001, d=0.76) or nulliparas (9.9±5.0, P=.322). Logistic regression disclosed the two-variable model (max-rescaled R2=0.37, P<.001) was more strongly associated with stress incontinence than either single-variable model, urethral closure pressure (R2=0.25, P<.001) or vesical neck movement (R2=0.16 P<.001). CONCLUSION: Lower maximal urethral closure pressure is the measure most associated with de novo stress incontinence after first vaginal birth followed by vesical neck mobility. LEVEL OF EVIDENCE: II