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 anteriorposterior 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.     

盆底器官脱垂患者肛提肌的动态MRI研究

目的:探讨盆底器官脱垂(POP)患者肛提肌的动态MRI表现特征,建立基于MRI的盆底肌肉和韧带损伤的诊断技术。方法:POP组32例,对照组15例。分别比较两组肛提肌裂隙、髂尾肌厚度、耻骨直肠肌厚度、髂尾肌角度和肛提肌板角度的变化。结果:(1)POP组肛提肌裂隙面积较对照组明显增大(P=0.008);(2)POP组左右侧髂尾肌和右侧耻骨直肠肌厚度在静息位和最大腹压时均较对照组薄,差异有统计学意义(P均<0.05);对比腹压作用前后肛提肌厚度的变化,两组差异均无显著性(P均>0.05);(3)最大腹压时,POP组髂尾肌角度和肛提肌板角度较对照组明显增大(P=0.001和0.007);比较腹压作用前后的角度变化,POP组有显著差异(P=0.003和0.044)。结论:MRI检查可以很好地观察肛提肌的形态,动态检查还可以评价肛提肌的功能状态。     

Static and dynamic MRI features of the levator ani and correlation with severity of genital prolapse

BACKGROUND: To describe the static and dynamic MRI features of the levator ani, and evaluate whether they are associated with the MRI evaluation of the severity of genital prolapse. METHODS: Static and dynamic MRI of 40 patients, referred for evaluation prior to genital prolapse surgery, were reviewed retrospectively. Prolapse severity was evaluated on MRI at maximal straining by descent of the bladder neck under the pubococcygeal line for the anterior compartment, by descent of the uterine cervix under the pubococcygeal line for the middle compartment, and by anterior bulging of the rectum for the posterior compartment. For evaluation of the levator ani, the following parameters were recorded: (1) at rest: thinning or defects in both puborectalis and iliococcygeus muscles, (2) at rest and at straining: urogenital hiatus length and width, M line, iliococcygeal and levator plate angles. The levator ani features were tested for potential associations with the MRI evaluation of prolapse severity. RESULTS: Bladder neck descent at straining was correlated with the levator plate angle at rest (p=0.001), and with the hiatus length at rest (p=0.02), and at straining (p=0.008). Uterine cervix descent at straining was correlated with the hiatus length (p=0.0005), and width (p=0.014) at straining, M line (p=0.002) and levator plate angle (p=0.007) at straining, whereas anterior rectal bulging at straining was paradoxically inversely correlated with the hiatus width at rest (p = 0.04). CONCLUSION: In a population of women with genital prolapse, MRI evaluation of the levator ani was associated with MRI evaluation of the severity of genital prolapse.     

Ultrasonographic and Doppler velocimetric evaluation of the levator ani muscle in premenopausal women with and without urinary stress incontinence

OBJECTIVES: The objective was to evaluate the cross-sectional area (CSA) and the Doppler velocimetric parameters of the levator ani muscle vessels in premenopausal women with and without urinary stress incontinence. STUDY DESIGN: Sixty-three premenopausal women constituted three groups: GI (nulliparous), GII (continent multiparous), and GIII (incontinent multiparous). The patients had undergone transperineal ultrasound in which the CSA was measured and Doppler velocimetry was performed. The examination was repeated by a second observer using the same procedure. RESULTS: There was a statistically significant correlation between the measurements of the observers I and II regarding all the parameters studied, except for the A/B ratio in GIII. The CSA was significantly greater in GI and GII than in GIII. As far as Doppler velocimetry is concerned there were no differences in the Doppler velocimetric indices among the three groups. Concerning the absent end diastolic shift, it was observed that there was a significantly greater incidence of such findings in GI+GII (continent women) towards GIII (incontinent women). CONCLUSIONS: The CSA evaluation and the Doppler velocimetry of the levator ani muscle vessels were highly reproducible. The CSA was higher in continent women and the frequency of the absent end diastolic shift was higher in incontinent women.     

Vacuum-assisted vaginal delivery and levator ani avulsion in primiparous women

Objective: We compared the incidence and type of levator ani avulsion diagnosed by translabial ultrasound evaluation in primiparous women six months after vacuum-assisted or spontaneous vaginal delivery.

Material and methods: This retrospective observational study was performed between January 2011 and December 2013. Primiparous women six months after vacuum-assisted vaginal delivery and after spontaneous vaginal delivery underwent translabial ultrasound evaluation. The distance between the urethra and fibers of the musculus levator ani puborectalis (levator–urethra gap) was measured. A levator-urethra gap?>25?mm was considered a musculus levator ani avulsion.

Results: In total, 184 women participated in the study. Among them, 92 had vacuum extraction and 92 had uncomplicated spontaneous delivery. A longer levator–urethra gap on both sides of the pubic bone was found in women after vacuum-assisted vaginal delivery (p?<?0.0001 for both sides). Musculus levator ani avulsion was identified in 20 women (unilateral in 16 cases and bilateral in four cases). No difference in an incidence of musculus levator ani avulsion was identified in women after vacuum-assisted vaginal delivery [11/92 (12%)] compared to spontaneous delivery [9/92 (10%); p?=?0.81].

Conclusion: Vacuum-assisted vaginal delivery in primiparous women is associated with a longer levator–urethra gap but not with a higher frequency of avulsion of the musculus levator ani.     

Two- and 3-dimensional MRI comparison of levator ani structure, volume, and integrity in women with stress incontinence and prolapse

OBJECTIVE: The aim of this study was to identify imaging markers for genuine stress incontinence and pelvic organ prolapse by using magnetic resonance imaging and reconstructed 3-dimensional models. STUDY DESIGN: Thirty women were studied, 10 with prolapse, 10 with genuine stress incontinence, and 10 asymptomatic volunteers. Axial and sagittal T1 and T2 weighted pelvic magnetic resonance scans were obtained with the patient in the supine position. Source images were measured to determine levator hiatus height, bladder neck to pubococcygeal line, levator plate angle, and perineal descent at rest and maximum Valsalva. Manual segmentation and surface modeling was applied to build 3-dimensional models of the organs. The 3-dimensional models were measured to determine levator muscle volume, shape and hiatus width, distance between symphysis and levator sling muscle, posterior urethrovesical angle, bladder neck descent, and levator plate angle. RESULTS: The 3 groups of subjects were comparable in age, parity, and body mass index. In the control, genuine stress incontinence, and prolapse groups, the menopausal rate was 40%, 60%, and 55% (P =.7). In the same order, significant mean 2-dimensional measures were: resting bladder neck descent of 24, 17, and 3 mm (P <.005), straining levator plate angle of -4.3, -11.5, and -31 degrees (P =.01), straining levator hiatus height of 48.5, 51.1, and 65.3 mm (P <.005), and straining perineal descent of 17.2, 22.5, 27.2 mm (P =.02). Similarly ordered mean 3-dimensional parameters showed levator volumes of 32.2, 23.3, and 18.4 cm(3) (P <.005); hiatus widths of 25.7, 34.7, and 40.3 mm (P <.005); left levator sling muscle gaps of 15.6, 20.3, and 23.8 mm (P =.03), right levator sling muscle gaps of 15.6, 22.5, and 30.8 mm, (P = 0.003), and levator shape (90%, 40%, and 20% dome shaped; P <.005). CONCLUSION: Both 2-dimensional magnetic resonance images and 3-dimensional models yield findings that differ among asymptomatic subjects compared with those with genuine stress incontinence and prolapse. Our 3-dimensional data demonstrate a statistically significant continuum in levator volume, shape, and integrity across groups of asymptomatic, genuine stress incontinence, and prolapse subjects.     

Interaction among apical support, levator ani impairment, and anterior vaginal wall prolapse

OBJECTIVE: To use a biomechanical model to explore how impairment of the pubovisceral portion of the levator ani muscle, the apical vaginal suspension complex, or both might interact to affect anterior vaginal wall prolapse severity. METHODS: A biomechanical model of the anterior vaginal wall and its support system was developed and implemented. The anterior vaginal wall and its main muscular and connective tissue support elements, namely the levator plate, pubovisceral muscle, and cardinal and uterosacral ligaments were included, and their geometry was based on midsagittal plane magnetic resonance scans. Material properties were based on published data. The change in the sagittal profile of the anterior vaginal wall during a maximal Valsalva was then predicted for different combinations of pubovisceral muscle and connective tissue impairment. RESULTS: Under raised intra-abdominal pressure, the magnitude of anterior vaginal wall prolapse was shown to be a combined function of both pubovisceral muscle and uterosacral and cardinal ligament ("apical supports") impairment. Once a certain degree of pubovisceral impairment was reached, the genital hiatus opened and a prolapse developed. The larger the pubovisceral impairment, the larger the anterior wall prolapse became. A 90% impairment of apical support led to an increase in anterior wall prolapse from 0.3 cm to 1.9 cm (a 530% increase) at 60% pubovisceral muscle impairment, and from 0.7 cm to 2.4 cm (a 240% increase) at 80% pubovisceral muscle impairment. CONCLUSION: These results suggest that a prolapse can develop as a result of impairment of the muscular and apical supports of the anterior vaginal wall.     

Real-time in vivo assessment of levator ani muscle deformation in women

Objective

To study the deformation of the levator ani muscle in vivo with the use of real-time ultrasound imaging of the pelvic floor.

Study design

Thirty-two women with symptoms of pelvic floor dysfunction underwent real-time in vivo assessment of the strain of the pelvic floor during Valsalva effort. All participants underwent clinical examination, urodynamics and 3D/4D translabial ultrasound scan of the pelvic floor. The deformation curves of the levator ani muscle were plotted and the difference in compliance according to the grade of urogenital prolapse was measured. One-way ANOVA and Spearman's correlation were used to test for significance of the relationship between variables (significance level P < 0.05). Test–retest analysis of the ultrasound measurements of the levator hiatal dimensions was also conducted using intra-class correlation coefficient (ICC).

Results

The deformation curve of the levator hiatus showed a non-linear relationship with gradually increased Valsalva force, which was quite pronounced in the pubourethralis subdivision of the levator ani muscle complex. Women with significant pelvic organ prolapse demonstrated a less compliant levator ani muscle close to its origin from the pubic bone than women with non-significant prolapse (median maximum strain 26% vs 32%, respectively, P = 0.03).

Conclusions

Real-time in vivo assessment of levator ani muscle deformation in women is feasible and yields significant information.     

Three-dimensional magnetic resonance imaging assessment of levator ani morphologic features in different grades of prolapse

OBJECTIVE: The study was undertaken to identify the morphologic changes in the levator ani in different grades of prolapse by using reconstructed three-dimensional models of magnetic resonance images (MRI) and to subclassify prolapse into different categories on the basis of their levator ani morphologic characteristics. STUDY DESIGN: Sixty-one women were studied, 8 women in stage I, 15 women in stage II, 22 women in stage III, 7 women in stage IV prolapse, and 9 asymptomatic volunteers with stage 0 prolapse. Axial, sagittal, and coronal T2-weighted pelvic magnetic resonance scans were obtained with the patient in the supine position. The three-dimensional models were reconstructed from the source images by using manual segmentation and surface modeling. The morphologic characteristics of the puborectalis were assessed on these reconstructed models by measuring (1). the levator symphysis gap, (2). the width of the levator hiatus, and (3). the length of the levator hiatus. To assess the iliococcygeus, we measured (1). the maximum width of the iliococcygeus, (2). the direction of its fibers that was assessed by measuring the iliococcygeal angle, and (3) the levator plate angle. Nine nulliparous asymptomatic women were studied as controls. RESULTS: Alterations in levator ani morphologic features are not dependent on the grade of the prolapse, and not all women with pelvic floor prolapse have abnormal morphologic features. In healthy control subjects, the iliococcygeal width measured less than 40 mm and the iliococcygeal angle measured less than 20 degrees. On the basis of the MRI findings, four patterns of changes in the levator ani have been identified. Both the levator symphysis gap and the levator hiatus, which is dependent on the puborectalis function, widen with increasing grade of prolapse. CONCLUSION: It is possible to subclassify prolapse on the basis of morphologic changes in the levator ani by using MRI. This may be a very useful predictor as to which patients have recurrent prolapse develop after surgery.     

Pelvic muscle electromyography of levator ani and external anal sphincter in nulliparous women and women with pelvic floor dysfunction

OBJECTIVE: The purpose of this study was to compare results of electromyographic assessment of muscular recruitment between nulliparous control subjects without pelvic floor dysfunction and parous subjects with genuine stress urinary incontinence and with pelvic organ prolapse. Interference pattern analysis is an electromyographic technique that reproducibly measures muscular recruitment by detecting both "turns" in the electromyographic signal produced by positive and negative peaks of the motor unit potentials and motor unit potential amplitude. Fewer turns can indicate loss of motor units or failure of central activation of contraction, whereas greater amplitude can indicate reinnervation after nerve damage. STUDY DESIGN: We performed concentric needle electrode electromyographic examinations of the levator ani and external anal sphincter in 15 nulliparous control subjects and 20 parous subjects with abnormalities (n = 9 with genuine stress urinary incontinence, n = 11 with stage III or IV pelvic organ prolapse). We made digital recordings at multiple sites at rest and with moderate and maximal contraction. Interference pattern analysis yielded the number of turns per second and the mean signal amplitude (in microvolts) for each site at each contraction level. We compared individual patient data with data from the healthy population by means of cloud analysis. Mean values of number of turns per second and mean amplitude in each group were then compared with nonparametric methods and regression models. RESULTS: Mean ages were 28.7 years (range, 20-49 years) for the control group, 54.3 years (range, 35-75 years) for subjects with genuine stress urinary incontinence, and 65 years (range, 41-77 years) for subjects with pelvic organ prolapse. Median clinical levator ani strengths were 9 (range, 5-9) in the control group, 5 (range, 2-7) in the genuine stress urinary incontinence group, and 5 (range, 2-8) in the pelvic organ prolapse group. Median external anal sphincter strengths were 9 (range, 7-9) in the control group, 5 (range, 3-9) in the genuine stress urinary incontinence group, and 8 (range, 4-9) in the pelvic organ prolapse group. The external anal sphincters of subjects with pelvic organ prolapse had the highest percentage of abnormal study results according to cloud analysis. Mean number of turns per second in levators was greater in control subjects than in subjects with abnormalities (P =.034). We found similar differences in number of turns per second for the external anal sphincter (P =.004). In contrast, we did not find differences between groups in mean amplitude in either the levator ani or the external anal sphincter. Comparison of patients with genuine stress urinary incontinence versus subjects with pelvic organ prolapse showed no significant difference in the number of turns per second in either muscle. Mean amplitude was greater in the pelvic organ prolapse group than in the genuine stress urinary incontinence group for both muscles (levator ani, P =.028; external anal sphincter, P =.048). Neither mean amplitude nor the number of turns per second could be predicted by clinically estimated levator ani strength, age, or fecal incontinence. CONCLUSION: Compared with nulliparous control subjects, patients with genuine stress urinary incontinence and pelvic organ prolapse had changes in the levator ani and external anal sphincter consistent with either motor unit loss or failure of central activation, or both. Subjects with pelvic organ prolapse had findings consistent with greater recovery than was found in those with genuine stress urinary incontinence. Measures of recruitment by interference pattern analysis correlated better with clinical external anal sphincter strength than with levator ani strength and were independent of age.     

压力性尿失禁及盆底组织膨出患者肛提肌形态学的观察

目的 探讨肛提肌组织形态学的变化及其与压力性尿失禁(stress urinary incontinence,SUI)和盆底组织膨出(pelvic organ prolapse,POP)发病的关系。方法 选择15例SUI患者(SUI组)、19例POP患者(POP组)及3例无SUI和POP的直肠癌患者(对照组),术中行肛提肌活检,冰冻切片常规行HE染色、改良Gomori染色及非特异性酯酶(non—specific esterase,NSE)、酸性磷酸酶(acidphosphrase,ACP)、三磷酸腺苷酶(ATPase)染色,镜下观察肛提肌形态学变化。结果 成功获取肛提肌肌肉组织与未取得肛提肌肌肉组织的SUI患者的年龄、产次、绝经时间、疾病严重程度、漏尿点压力等比较,差异均无显著性(P>0.05)。SUI组和POP组患者肛提肌组织形态学表现为肌纤维密度降低,排列紊乱,被大量的结缔组织填充、取代,肌纤维周围炎性细胞浸润;单个肌纤维细胞既有核中心移位、纤维劈裂、外周吞噬及空泡变性等肌源性改变,也有肌纤维萎缩、角形变、同型纤维聚集等神经源性改变。结论 SUI和POP患者的肛提肌同时存在神经源性和肌源性改变,提示持续的盆底肌去神经支配和继发的肌源性改变,可能是SUR及POP的发病原因之一。     

Changes in levator ani muscle after vaginal hysterectomy and prolapse repair using the Total Prolift procedure

Objective

To assess changes in the levator plate angle (LPA), anteroposterior length of the levator hiatus (H-line), and pelvic floor descent (M-line) after vaginal hysterectomy and prolapse repair using the Gynecare Prolift Total Pelvic Floor Repair System.

Methods

Before and after the intervention, 20 women with pelvic floor prolapse underwent dynamic magnetic resonance imaging in supine position during the Valsalva maneuver to measure the LPA, H-line, and M-line. Paired t tests were performed and Pearson correlation coefficients calculated from values obtained using the pelvic organ prolapse quantification system.

Results

After the intervention the LPA was smaller (46.92° vs 55.39°, P < 0.05), the H-line was shorter (53.70 cm vs 60.46 cm, P < 0.05), and the M-line was shorter (19.58 cm vs 25.27 cm, P < 0.05).

Conclusion

These changes suggest an efficient reconstruction and reinforcement of the pelvic floor after the surgery.     

Quantitative electromyographic analysis of levator ani and external anal sphincter muscles of nulliparous women

OBJECTIVES: Our aims were to introduce a method of digital quantitative electromyography of the levator ani and external anal sphincter muscles and to establish reference values. STUDY DESIGN: Fifteen nulliparous, symptom-free women underwent concentric needle electromyographic examination of the levator ani and external anal sphincter. We sampled the levator ani transvaginally at 4 sites and the external anal sphincter at 2 sites. The signal was filtered and amplified, and digital recordings were made at 3 levels of voluntary activation at each site. Analyses of motor unit action potentials and interference patterns were performed with the use of these taped signals. Normal ranges were generated and compared with those established for other striated muscles. RESULTS: The mean age of the subjects was 28.7+/-7.5 years. A median of 24 motor unit action potentials was recorded in each levator ani, and a median of 6 was recorded in each external anal sphincter. Parameters of the levator ani action potentials were significantly greater than those of the external anal sphincter in amplitude (0.48 vs. 0.37 mV; P =.001), duration (10.40 vs. 8.27 ms; P =.002), number of turns per second (2. 80 vs. 2.28; P<.001), and area (0.65 vs. 0.36; P<.001). Parameters of the interference patterns were significantly greater in the levator ani than in the external anal sphincter in number of turns per second (241.6 vs. 183.9; P =.015), amplitude (302.7 vs. 225.3 microV; P<.0001), activity (95.6 vs 61.2; P =.004), envelope size (861.1 vs 567.6 microV; P<.0001), and number of small segments (105. 8 vs 81.4; P =.047). There were no significant differences between levator ani, external anal sphincter, and published parameters from the biceps muscle with regard to amplitude and duration of motor unit action potentials. CONCLUSIONS: Electromyography of the levator ani and external anal sphincter is feasible and well tolerated. Our findings confirm that the levator ani muscle has larger, more readily recruited motor units than does the external anal sphincter. Ranges for important quantitative electromyographic parameters for these muscles are similar to those published for the biceps.     

Antigenic differences between the endometrium of women with and without endometriosis

Serum and peritoneal fluid from 12 women with endometriosis, 4 women with uterine leiomyomata and 6 fertile women without endometriosis (controls) and serum from 4 women with adenomyosis were tested with a passive hemagglutination assay for antibodies against endometrium from all the controls, 8 patients with endometriosis and all patients with uterine leiomyomata and from implants from 8 patients with endometriosis. Serum antibody titers in patients with endometriosis or leiomyomata were significantly higher against endometrial or implant antigens from patients with endometriosis and 2 patients with leiomyomata than those against the controls' endometrium. Peritoneal fluid endometrial antibody titers failed to reflect these antigenic differences. Controls and patients with adenomyosis had low titers of endometrial antibodies in their serum or peritoneal fluid. Antigenic differences appear to exist between the endometrium of patients with endometriosis and that of controls.     

Computed tomography comparison of bony pelvis dimensions between women with and without genital prolapse

Objective: To compare bony pelvis dimensions between white women with and without genital prolapse using computed tomography (CT) pelvimetry.Methods: Thirty-four multiparous white women with vaginal prolapse beyond the hymen and 34 matched white controls with no signs or symptoms of pelvic support defects underwent CT pelvimetry. The anteroposterior and transverse diameters of the pelvic inlet, the interspinous diameter of the midpelvis, and the intertuberous diameter of the pelvic outlet were measured. Post hoc power analysis showed that 22 women were needed in each group to detect a 10% difference in the pelvic dimensions between groups, with an α error of 1% and a β error of 10%, resulting in a 90% power.Results: Mean (± standard deviation [SD]) age of the subjects was 63.4 ± 8.3 years, compared with 62.9 ± 7.8 years for controls. Mean parity of the subjects was 3.3 ± 1.7, compared with 3.6 ± 1.7 for controls. Mean (± SD) anteroposterior (12.5 ± 1.3 versus 12.8 ± 1.0 cm), interspinous (11.5 ± 0.8 versus 11.2 ± 0.9 cm), and intertuberous (10.0 ± 1.0 versus 9.8 ± 0.8 cm) diameters were not significantly different between study groups. Mean transverse diameter of the pelvic inlet was significantly greater in women with prolapse than those without prolapse (12.9 ± 0.7 versus 12.4 ± 0.6 cm, P = .006).Conclusion: Women with advanced vaginal prolapse have larger transverse inlet diameters than do women with normal pelvic support.     

Relationship between levator ani contraction and motor unit activation in the urethral sphincter

OBJECTIVE: The purpose of this study was to evaluate the relationship between levator ani contraction and motor unit action potential activation in the striated urethral sphincter. STUDY DESIGN: One hundred eight women who underwent preoperative evaluation at our referral center were studied. All women gave a urogynecologic history and underwent physical examination, multichannel urodynamic testing, and urethral sphincter electromyography. Manual muscle testing was used to grade levator ani contractions as poor, moderate, or strong; quantitative electromyography software was used to analyze motor unit action potential activation in the urethral sphincter. RESULTS: Levator ani contractions were graded as poor in 46% of the women, moderate in 31% of the women, and strong in 23% of the women. Manual muscle grade was not related to quantitative electromyography values in the urethral sphincter at rest or with voluntary pelvic floor contraction. Poor manual muscle grade was associated with detrusor instability (P =.004) and more advanced stages of prolapse (P =.037). Levator ani strength was not significantly related to age, genuine stress incontinence, urethrovesical junction hypermobility, menopausal status, or surgical cure rates. CONCLUSION: The ability to contract the levator ani does not appear to be related to the ability to activate motor unit action potentials in the urethral sphincter, which suggests that the function of the levator ani in maintaining urinary continence is independent from the role of the urethral sphincter.     

MRI morphology of the levator ani muscle, endopelvic fascia, and urethra in women with stress urinary incontinence

OBJECTIVE: To evaluate pathomorphologic changes of the levator ani muscle, endopelvic fascia, and urethra in women with stress urinary incontinence (SUI) by MRI. STUDY DESIGN: Fifty-four women with SUI were examined by MRI (1.5T): body phased-array coil, axial and coronal proton-density-weighted sequences. RESULTS: The urethral sphincter muscle showed a reduced thickness of its posterior portion (37%), an omega shape (13%) or higher signal intensity (50%); its abnormal configuration was associated with an increased signal intensity in 70% (p=0.001). The levator ani muscle comprised an unilateral loss of substance in 30%, a higher signal intensity in 28%, and altered origin in 19%. Central defects of the endopelvic fascia were present in 39% (n=21), lateral defects in 46%. There was a significant association between loss of the symphyseal concavity of the anterior vaginal wall and lateral fascial defects (p=0.001) and levator ani changes (p=0.016). CONCLUSION: MRI yields findings supporting current theories on the pathogenesis of SUI.