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abstract

128 - PELVIS AND PELVIC FLOOR MORPHOLOGY OF HEALTHY NULLIPAROUS WOMEN ON MRI

128

PELVIS AND PELVIC FLOOR MORPHOLOGYOF HEALTHY NULLIPAROUS WOMEN ON MRI

O. GOJIS 1, L. KROFTA 1,I. URBANKOVA 2, M. KRCMAR3, F. JAROSLAV1;
1Dep. of Urogynecology, The institue forthe care of mother and and child, Prague 4, Czech Republic, 2KULeuven, Leuven, Belgium, 3urogynecology, Inst. for thecare of mother and child, Prague 4, Czech Republic.

Introduction: The magneticresonance imaging (MRI) produces detailed pictures of the softtissues and bone structures of the pelvic floor. To analyzemorphological changes in women with pelvic floor dysfunction we haveto know the magnitude of normal variation among healthy nulliparouswomen.
Objective: This study aims to describe thephysiological variability of the pelvis, levator ani and theobturator muscle in healthy nulliparous women.
Methods:Twenty-four healthy nulliparous women with normal pelvic organsupport were recruited to undergo a 3T magnetic resonance imaging(MRI) of the pelvis and pelvic floor. MRI scans were performed in allthree projections (slice thickness 2mm, inter-slice gap 0mm) and adynamic midsagittal scan during the Valsalva maneuver plane. Axialand sagittal scans and dynamic sequence were evaluated by twoindependent researchers. In the axial scans, anatomy was evaluated intwo parallel planes; (1) at the plane of the inferior pubic ligamentthat corresponds to the mid-urethra (pL1), and (2) at the planedefined by the bladder base (pL2). Following biometric parameterswere measured1: urogenital hiatus dimensions(anteroposterior dimension, width), the distance between the urethraand puborectal muscle insertion (urethral gap, UG), levator animuscle thickness (pubovisceral muscle complex and iliococcygealmuscle, respectively), the internal obturator muscle thickness (onlyat pL2). Also, the distance between pL1 and pL2 was measured. Axialscans were also used to measure the pelvic bones biometry includingthe sacrococcygeal-inferior pubic point distance (SCIPP), thebi-spinal and bi-tuber diameter. In dynamic sequences measurementswere done at the rest and at the maximal Valsalva maneuver. Wemeasured the distance between the posterior aspect of the uterinecervix and the sacrococcygeal connection, the levator plate angle,and the sacrouterine angle, which was defined as an angle between theSCIPP line and connection between the sacrococcygeal connection andthe posterior aspect of the uterine cervix. The difference betweenleft- and right-sided measurements was compared with a paired T-test(SPSS®, ver. 19).
Results: The mean age and BMIwere 27.5years ±3.3 (22, 34) and 22.6kg/m2±2.0 (18.8,26.3), respectively. There were no differences in the left and rightsided structures (i.e. levator ani, obturator muscle). All datashowed normal distribution, thus they are reported as mean ±standard deviation, and range. At pL1: urethral gap 14.00mm ±2.5(10; 19), pubovisceral muscle-complex thickness 8.1mm ±1.6 (4; 11).At pL2: iliococcygeal muscle thickness 4.6mm ±1.7 (1, 10), obturatormuscle thickness 17.6mm ±3.9 (11, 26). The average distance betweenpL1 and pL2 was 21.5mm ±5.0 (12, 30). The bony pelvis dimensions:bispinal diameter 109.2mm ±8.9 (96, 128), bi-tuber distance 128.2mm±10.4 (109, 149), SCIPP 115.9mm ±25.7 (97.0, 146.0), and theinterpubic angle 86.3° ±8.9 (96, 128). Dynamic midsagittalsequences: the sacrococcygeal-uterine cervix distance at the rest55.0mm ±15.2 (29, 92) and at the Valsalva 49.4mm ±10.6 (33, 75);the levator plate angle at relaxation 21.5° ±7.1 (11.3, 39) and atValsalva 34.7° ±10.4 (14.2, 52.3); the sacro-uterine angle atrelaxation 30.5° ±9.3 (14.3, 50.1) and at Valsalva 19.2° ±12.7(-8.6, 41.2).
Conclusions: MRI is a suitable modality toanalyse in vivo normal anatomy variations. In healthy nulliparouswomen the variability of MLA subdivisions is low. Standardizedinvestigation technique and knowledge of normal anatomy variationsare essentials to discover pelvic floor dysfunction.
References:Ref doi:10.1067/mob.2003.58