Pelvic Floor Structures Research Articles

Women's Bike Seats: A Pressing Matter for Competitive Female Cyclists

There are numerous genital complaints in women cyclists, including pain, numbness, and edema of pelvic floor structures. Debate ensues about the best saddle design for protection of the pelvic floor. To investigate the relationships between saddle design, seat pressures, and genital nerve function in female, competitive cyclists. We previously compared genital sensation in healthy, premenopausal, competitive women bicyclists and runners. The 48 cyclists from our original study comprise the study group in this subanalysis. Main outcome measures were: (i) genital vibratory thresholds (VTs) determined using the Medoc Vibratory Sensation Analyzer 3000 and (ii) saddle pressures as determined using a specially designed map sensor. More than half of the participants (54.8%) used traditional saddles, and the remainder (45.2%) rode with cut-out saddles. On bivariate analysis, use of traditional saddles was associated with lower mean perineal saddle pressures (MPSP) than riding on cut-out saddles. Peak perineal saddle pressures (PPSP) were also lower; however, the difference did not reach statistical significance. Saddle design did not affect mean or peak total saddle pressures (MTSP, PTSP). Saddle width was significantly associated with PPSP, MTSP, and PTSP but not with MPSP. Women riding cut-out saddles had, on average, a 4 and 11 kPa increase in MPSP and PPSP, respectively, compared with women using traditional saddles (P = 0.008 and P = 0.010), after adjustment for other variables. Use of wider saddles was associated with lower PPSP and MTSP after adjustment. Although an inverse correlation was seen between saddle pressures and VTs on bivariate analysis, these differences were not significant after adjusting for age. Cut-out and narrower saddles negatively affect saddle pressures in female cyclists. Effects of saddle design on pudendal nerve sensory function were not apparent in this cross-sectional analysis. Longitudinal studies evaluating the long-term effects of saddle pressure on the integrity of the pudendal nerve, pelvic floor, and sexual function are warranted.

Biomechanics of the female pelvic floor: a prospective trail of the alteration of force–displacement-vectors in parous and nulliparous women

We hypothesize that the holistic and multiplanar depiction of pelvic floor structures by dynamic MRI is of particular value in rendering information about the extent of functional changes that can lead to pelvic floor dysfunction. 134 women were prospectively included for assessment of their pelvic floor function. Study groups differed significantly in the direction of their force-displacement-vectors. A shift from ventral to dorsal is present depending on parity, mode of delivery and age. Maternal age and body height correlated to the force-displacement-vector, whereas maternal weight did not. Pressing direction proved to be dependent on the inclination of the pelvis and the aperture of the levator hiatus while remaining independent from the aperture of the abdominal wall. Biomechanical data interpretation uncovered the pathogenetic relevance of progressive retroflection of the force-displacement-vector. This is responsible for the onset of a vicious cycle of trauma-related force deflection perpetuating pelvic floor traumatization.

Endoanorectal Ultrasonography

Endoanorectal ultrasonography (EARUS) may be used for diagnosing various anorectal disorders. EARUS is easy to perform, has a short learning curve, and causes less discomfort than routine digital examination. Anal sphincters can be clearly visualized, and one can easily distinguish between the internal (hypoechoic) and external (hyperechoic) anal sphincters. Other pelvic floor structures, like the puborectalis muscle, can also be visualized. The use of contrast agents can increase the accuracy of EARUS in the assessment of perianal fistulae. In addition, EARUS is an excellent alternative to expensive magnetic resonance imaging. Besides its use in incontinence and perianal sepsis, the presence of slight or massive submucosal invasion in early rectal cancer may be imaged in greater detail. With 3-dimensional EARUS, it is possible to diagnose the anorectal diseases, in multiplane, with high spatial resolution, adding important information about the therapeutic decision. The normal sonographic anatomy of the anorectum, sonographic findings of anorectal diseases, and indications and limitations of endosonography with complementary techniques such as transvaginal and transperineal ultrasound are reviewed in this article.

Malignant Tumors of the Female Pelvic Floor: Imaging Features That Determine Therapy: Pictorial Review

Objective The objective of this article is to discuss malignant tumors of the female pelvic floor and the imaging features that determine therapy. Conclusion After completing this article, the reader should have an improved ability to explain the clinically important anatomic structures of the female pelvic floor and the malignant tumors that arise from each of them; identify the tumor growth patterns on CT, MRI, and PET that preclude complete surgical resection; and recognize malignant transformation of endometriosis on MRI.

Segmentations of MRI images of the female pelvic floor: A study of inter‐ and intra‐reader reliability

To describe the inter- and intra-operator reliability of segmentations of female pelvic floor structures. Three segmentation specialists were asked to segment out the female pelvic structures in 20 MR datasets on three separate occasions. The STAPLE algorithm was used to compute inter- and intra-segmenter agreement of each organ in each dataset. STAPLE computed the sensitivity, specificity, and positive predictive values (PPV) for inter- and intra-segmenter repeatability. These parameters were analyzed using intra-class correlation analysis. Correlation of organ volume to PPV and sensitivity was also computed. Mean PPV of the segmented organs ranged from 0.82 to 0.99, and sensitivity ranged from 33 to 96%. Intra-class correlation ranged from 0.07 to 0.98 across segmenters. Pearson correlation of volume to sensitivity were significant across organs, ranging from 0.54 to 0.91. Organs with significant correlation of PPV to volume were bladder (-0.69), levator ani (-0.68), and coccyx (-0.63). Undirected manual segmentation of the pelvic floor organs are adequate for locating the organs, but poor at defining structural boundaries.

Modeling childbirth: elucidating the mechanisms of labor

The process of childbirth and the mechanisms of labor have been studied for over a century, beginning with simple measurements of fetal skull and maternal pelvis dimensions. More recently, X-rays, ultrasound, and magnetic resonance imaging have been used to try and quantify the biomechanics of labor. With the development of computational technologies, biomechanical models have emerged as a quantitative analysis tool for modeling childbirth. These methods are well known for their capabilities to analyze function at the organ scale. This review provides an overview of the state-of-the-art finite element models of the mechanics of vaginal delivery, with detailed descriptions of the data sources, modeling frameworks, and results. We also discuss the limitations and improvements required in order for the models to be more accurate and clinically useful. Some of the major challenges include: modeling the complex geometry of the maternal pelvic floor muscles and fetal head motion during the second stage of labor; the lack of experimental data on the pelvic floor structures; and development of methods for clinical validation. To date, models have had limited success in helping clinicians understand possible factors leading to birth-induced pelvic floor muscle injuries and dysfunction. However, much more can be achieved with further development of these quantitative modeling frameworks, such as tools for birth planning and medical education.

Fecal incontinence in older women: are levator ani defects a factor?

We sought to compare pelvic floor structure and function between older women with and without fecal incontinence (FI) and young continent (YC) women. YC (n=9) and older continent (OC) (n=9) women were compared to older women with FI (older incontinent [OI]) (n=8). Patients underwent a pelvic organ prolapse quantification, measurement of levator ani (LA) force at rest and with maximum contraction, and magnetic resonance imaging. Displacement of structures and LA defects were determined on dynamic magnetic resonance imaging. LA defects were more common in the OI vs the YC (75% vs 11%, P=.01) and OC (22%, P=.14) groups; women with FI were more likely to have LA defects than women without (odds ratio, 14.0, 95% confidence interval, 1.8-106.5). OI women generated 27.0% and 30.1% less force during maximum contraction vs the OC (P=.13) and YC (P=.04) groups. During Kegel, OI absolute structural displacements were smaller than in the OC group (P=.01). OI women commonly have LA defects, and cannot augment pelvic floor strength.

Dynamic magnetic resonance imaging for assessment of minimally invasive pelvic floor reconstruction with polypropylene implant

Introduction The purpose of the study was to assess the usefulness of dynamic MRI in patients with pelvic organ prolapse after pelvic floor repair with polypropylene mesh. Materials and methods Fifteen consecutive patients (mean age 66.5 years) who were scheduled for either anterior ( n = 9) or posterior ( n = 6) pelvic floor repair were prospectively evaluated by clinical assessment and dynamic MRI 1 day before and 3 months after surgery. MRI diagnoses and MRI measurements of relevant anatomical points at rest and on straining were analysed before and after surgery. Results At follow-up assessment 93.3% of all patients were clinically cured. Dynamic MRI showed newly developed ( n = 6) or increased ( n = 6) pelvic organ prolapse in 80% ( n = 12) of all patients 3 months after pelvic floor repair. Most of them ( n = 11; 91.7%) affected the untreated pelvic floor compartment. On straining anatomical points of reference in the anterior pelvic floor compartment were significantly ( p < 0.05) elevated after anterior repair and rectal bulging was significantly ( p = 0.036) reduced after posterior pelvic floor repair. Conclusions In this study dynamic MRI could verify the effective support of anterior and posterior pelvic floor structures by anterior and posterior polypropylene implant respectively. But dynamic MRI demonstrates if one compartment of the pelvic floor is repaired another compartment frequently (73.3%) develops dysfunction. These results did not correspond to clinical symptoms on short-term follow-up (3 months). Studies with long-term follow-up are necessary to prove if dynamic MRI can reliably identify clinically significant pelvic organ prolapse after pelvic floor repair before the onset of symptoms.

The Pathophysiology, Diagnosis and Treatment of Constipation: Obsolescence of X-ray Defecography

Muller-Lissner in his article mentions conventional x-ray defecography as the imaging procedure of choice in the diagnosis of defecation disorders. This procedure is obsolete, owing to its radiation exposure and its limited validity. Dynamic magnetic resonance imaging (MRI) of the pelvic floor, which is unfortunately not mentioned at all, can be conducted speedily and simply. It does not entail exposure to ionizing radiation and is better tolerated by patients. The reason is that the investigators are outside the room where the patient is lying in the scanner and evacuates into diapers. It was shown years ago that analyzing defecation while the patient is lying down is equivalent to analyzing it while the patient is sitting up (2). Since defecation disorders are often complex dysfunctions of the pelvic floor, a further advantage lies in the fact that by using MRI, the bladder, urethra, vagina, and uterus can be imaged during one examination, without the need for any further invasive procedures or for contrast medium (1). MRI also enables the representation of complications such as enterocele or sigmoidocele. High resolution imaging of the pelvic floor structures allows for assessment of atrophies and scarring of the levator sling as well as the fascia and ligaments of the pelvic floor (3).

Pelvic structure and function at 1 month compared to 7 months by dynamic magnetic resonance after vaginal birth

We sought to determine whether changes exist in location and movement of pelvic floor structures at 1 and 7 months postpartum. Midsagittal magnetic resonance images from 13 primiparous women with birth events associated with levator ani damage at early ( approximately 1 month) and late ( approximately 7 months) postpartum time points were analyzed. Pelvic floor structure locations at rest and displacements from rest to maximum Kegel and Valsalva were determined. Urogenital and levator hiatus diameters were measured as well. The perineal body was 7.1 mm and anal verge 7.9 mm higher at 7 months postpartum (P = .003). Both the urogenital and levator hiatus diameters were smaller at 7 months (P < .05). Displacement during Kegel and Valsalva was similar between the 2 time points. Resting locations of the perineal body and anal verge are higher at 7 months postpartum, but the amount of movement during Kegel or Valsalva does not change.

Imaging pelvic floor dysfunction

Pelvic floor function and structure are complex, and imaging (integrated with an understanding of physiology) is central to guiding the clinician in managing patients with incontinence, constipation, difficult rectal evacuation and pelvic organ prolapse. Multimodal imaging techniques such as static and dynamic imaging techniques (sometimes combined in a single sitting) have revolutionised our understanding of functional anatomy. The advent of endo-luminal imaging has increased our spatial resolution by its closer proximity to the area of interest. Dynamic imaging gives us a near physiological data set which helps us to simulate what is likely to happen in real life and gives us a better understanding of the multifactorial causes, and consequences, of pelvic floor dysfunction.

Measurements from image-based three dimensional pelvic floor reconstruction: a study of inter- and intraobserver reliability.

To describe inter- and intraobserver reliability of 3D measurements of female pelvic floor structures. Twenty reconstructed MR datasets of primiparas at 6-12 months postpartum were analyzed. Pelvic organ measurements were independently made twice by three radiologists blinded to dataset order. A "within-reader" analysis, a "between-reader" analysis, and the intraclass correlation (ICC), and standard deviation ratio (SDR) were computed for each parameter. Fifteen continuous variables and one categorical variable were measured. Eight continuous parameters showed excellent agreement (ICC >0.85 / SDR <0.40), five parameters showed relatively good agreement (ICC >0.70 / SDR >or=0.40, <0.60). Two parameters showed poor agreement (ICC <or=0.70 and/or SDR >or=0.60). The categorical variable showed poor agreement. Agreement was best where landmark edges were well defined, acceptable where more "reader judgment" was needed, and poor where levator defects made landmarks difficult to identify. Automated measurement algorithms are under study and may improve agreement in the future.

High-resolution three-dimensional endovaginal ultrasonography in the assessment of pelvic floor anatomy: a preliminary study

Our aim was to evaluate the morphological characteristics of the female pelvic floor that may be further elucidated with three-dimensional endovaginal ultrasonography (3D-EVUS). A consecutive series of 20 nulliparous females underwent 3D-EVUS. Measurements were determined according to pre-established criteria. Descriptive statistics and Spearman's correlation test were performed. The levator hiatus (LH) was measured in the oblique plane parallel to the pubovisceral muscle. A positive correlation was found between LH area and age (p = 0.03). The anteroposterior diameter of the urogenital hiatus, measured in the axial plane tilted from the symphysis pubis to the ischiopubic rami, correlated with LH area (p = 0.008). No urethral rotations were observed in the coronal plane. Significant correlations were found among urethral parameters. Mean anal sphincter measurements were comparable to previously reported magnetic resonance imaging and ultrasound measurements. 3D-EVUS allows measurements of key pelvic floor structures in planes that cannot be determined by conventional imaging modalities.

Biomechanical Analyses of the Efficacy of Patterns of Maternal Effort on Second-Stage Progress

To develop and use a biomechanical computer model to simulate the effect of varying the timing of voluntary maternal pushes during uterine contraction on second-stage labor duration. Published initial pelvic floor geometry was imported into technical computing software to build a simplified three-dimensional biomechanical model with six representative viscoelastic levator muscle bands interconnected by a hyperelastic iliococcygeal raphe. An incompressible sphere simulated the molded fetal head. Forces from uterine contraction and voluntary expulsive efforts were summed to push the model fetal head along the curve of Carus opposed by the resistance of the pelvic floor structures to stretch. Holding uterine maximal contraction force and push strength constant, pushes were timed before ("pre"), at ("peak"), and after ("post") maximal uterine contraction force. The effect of different combinations of pushes on second stage duration and the number of pushes required for delivery were evaluated. Calculated second stage durations ranged from 57.5 minutes (triple or pre-peak-post pattern) to 75.8 minutes (prepush and postpush patterns). Delivery with the triple-push pattern required 59 voluntary pushes, while the peak-push pattern required 23 voluntary pushes, a 61% reduction. The corresponding reduction for the pre-and-peak-push pattern was 29%, the peak-and-post push pattern was 30%, the prepush pattern was 54%, and the postpush pattern was 56%. Although the triple-push pattern resulted in a 16% shorter second stage, this came at the energetic expense of a 61% increase in the number of pushes required. III.

Recovery of Continence Function following Simulated Birth Trauma Involves Repair of Muscle and Nerves in the Urethra in the Female Mouse

BackgroundThe natural history and the mechanisms behind the alteration of vaginal distension (VD) in a mouse model are not clear. ObjectiveWe examined the temporal sequelae of VD and pudendal nerve transection (PNT) on leak-point pressure (LPP) and the muscular and nerve components of the urethra in mice. Design, setting, and participantsSeventy-two virgin female C57BL/6 mice were equally distributed into three groups. The VD group underwent VD for 1h. The PNT group received bilateral PNT. A control group underwent sham VD. InterventionEach group was divided into four subgroups of six mice for measurement of LPP at 0, 4, 10, and 20 d after VD or PNT. MeasurementsLPP was measured. Morphology and neurofilament-immunoreactive nerve of the urethra were assessed. Results and limitationsLPP was decreased at 0, 4, and 10 d but not at 20 d after VD. Decreased LPP persisted to 20 d in the PNT group. The external urethral striated muscle appeared disrupted and/or wavy in two mice at 0 d, in three mice at 4 d, in one mouse at 10 d, and in one mouse in 20 d after VD. The density of neurofilament-immunoreactive nerve in the urethra was reduced at 4 and 10 d after VD, but not at 20 d, and at 4, 10, and 20 d after PNT compared with the corresponding values of the sham VD group. The limitation of this animal model is that the pelvic floor structure of the mouse is different from that of female humans. Therefore, results of this study should be carefully applied to human subjects. ConclusionsVD causes reversible stress urinary incontinence in female mice. Recovery of continence function following VD is associated with repair of the external urethral sphincter and reinnervation of the urethra. This mouse model will be useful for mechanistic investigation and targeting of therapeutic intervention by taking advantage of genetic manipulation.

Reproducibility of ultrasonic measurements of pelvic floor structures in women suffering from urinary incontinence

The aim of this study was to examine the reproducibility of ultrasound (US) findings relating to pelvic floor muscle in women with urinary incontinence (UI). Eighteen women with UI were examined twice by the same examiners over an interval of 1 month. The US findings comprised of (1) distance between bladder neck and symphysis pubis (BN/SP) at rest, during contraction, and while performing the Valsalva maneuver and (2) distance between anorectal angle and symphysis pubis (AR-SP) during the same conditions. Statistical analysis included test-retest correlations (ICC(3,K)), and the assessment of measurement error and smallest real difference (SRD) for change. BN-SP and AR-SP exhibited high ICCs. The lowest SRD values related to the AR-SP variables (10-19%). US-based measures of the bladder neck and the anorectal angle, distance, and displacement seem to offer reasonable clinical reproducibility.

Safe manual handling: pelvic floor considerations

Occupational health and safety (OHS) legislation in Ausralia and the UK requires organisations to identify, assess and ontrol hazards related to manual tasks at work [1,2]. To fulll their OHS training obligations, organisations frequently ngage physiotherapists and other trainers to conduct manual andling education sessions for staff. This education follows risk management approach to reduce musculoskeletal injury rom manual tasks. These sessions often focus on low back njury prevention; however, little attention has been paid to ossible injury of pelvic floor structures, despite a growing vidence base for a link between the structures within the bdominopelvic region [3–6]. This article aims to provoke iscussion and debate about the inclusion of information on he pelvic floor in manual handling training sessions. Sugestions for a screening tool to be used prior to training are ncluded.

Ageing of the female pelvic floor: towards treatment a la carte of the “geripause”

The study of menopause and female ageing “geripause” is receiving much attention lately from the health care community for three main reasons [1–3]. The first is the global increase in female life expectancy as a result of improved health awareness and services with continuing reduction of adult mortality, progressive transition from high to low fertility, and recent socioeconomic affluence in most countries. This unprecedented demographic change, which started in the developed world in the 19th century and more recently in developing countries, allowed women to experience menopausal manifestations during approximately one third of their lifespan and reach the geripause. Secondly, the process of medicalization within the broader context of the dominance of health as a cultural preoccupation in recent societies and women’s motivation by personal concerns and cultural forces to take more control of the effects of menopause and/or ageing on their bodies has resulted in increasing use of female sex hormones as a replacement therapy. Finally, there is a growing public and medical concern about the serious adverse effects of estrogen/progestin replacement therapy in old postmenopausal “geripausal” women that had been recently reported in the Women’s Health Initiative Trial. This is accompanied by considerable interest in the contemporary biomedical literature, in particular, about the prevalence, detrimental effects, and management of support-related pelvic floor dysfunction (pelvic organ prolapse, urinary incontinence, and fecal incontinence) in the geripausal population. There seems to be no consensus, however, whether the exact underlying mechanism is normative ageing, falling circulating estrogen levels caused by menopausal ovarian failure, or a combination of both factors [3–9]. It is widely believed that estrogen deprivation at the climacteric is primarily responsible for support-related pelvic floor dysfunction in geripausal women. This assumption is based on the detection of estrogen receptors in the components of continence-maintaining and supportive pelvic floor structures in premenopausal women and experimental animals [3–6]. In turn, estrogen replacement had been extensively used to prevent or restore the decline in pelvic floor support and/or deterioration of urinary and fecal control after the menopause but without critical analysis of the long-term cure rates or evidence-based improvement in clinical outcome after treatment in most studies [7]. Paradoxically, a recent meta-analysis and a Int Urogynecol J (2008) 19:455–458 DOI 10.1007/s00192-008-0576-0

Anatomical considerations in TNM staging and therapeutical procedures for low rectal cancer

Separation of the mesoderm-derived muscular structures and the endoderm-derived structures of the hindgut and reclassification of their involvement based on their embryological origin may be of clinical importance in providing anatomical support for a more standardized perineal resection during abdominoperineal resection. The aim of this study was to utilize magnetic resonance images and histological studies of fetal and neonatal specimens to redefine the T3/T4 distinction by reassessment of the intersphincteric plane and the pelvic diaphragm as they pertain to cancer infiltration and as part of the embryological development of the pelvic floor muscles and their connective tissue compartments. Pelvic floor anatomy was studied in seven newborn children and 120 embryos and fetuses. Anatomical data were completed by magnetic resonance imaging in 82 patients with T3 and T4 rectal cancers (64 T3, 18 T4; 35 women and 47 men) undergoing neoadjuvant chemoradiation for locally advanced (T3 or T4) rectal cancers. Clear demarcation between mesodermal and endodermal structures of the pelvic floor, which is equally evident in plastinated sections and magnetic resonance images, is already visible in early fetal stages. There is a constitutive overlap between the endoderm- and the ectoderm-derived components of the pelvic floor. Our data suggest that the current classification of rectal cancer staging is confusing, where the routinely used TNM classification system unnecessarily differentiates between embryologically identical muscular structures. Tumor spread along the musculature of the hindgut beyond the dentate line could possibly explain the occasional involvement of lymph nodes outside the conventional mesorectum.

Three‐dimensional ultrasound imaging of the levator hiatus in late pregnancy and associations with delivery outcomes

To determine the correlations between dimensions of the levator hiatus in late pregnant nulliparous women, mode of delivery and length of second stage. This was a prospective observational pilot study of 61 nulliparous women seen and examined between 36 and 40 weeks of pregnancy. A translabial ultrasound examination was undertaken, and three-dimensional volumes comprising the levator hiatus were recorded at rest, during a pelvic floor muscle contraction and on Valsalva. The volumes were analysed in a blinded fashion using proprietary software to determine linear dimensions and hiatal area. Information regarding delivery outcomes and course of labour was obtained from the obstetric database. Statistical analysis was undertaken for correlations between hiatal dimensions and labour outcomes. No consistent correlations were found between levator dimensions and delivery mode. However, an inverse correlation was demonstrated between the area of the hiatus, particularly on pelvic floor contraction, and length of total second stage. Levator hiatal dimensions are associated with the length of the second stage of labour. Although the numbers were small, our findings suggest that the effect of pelvic floor structures on progress in labour is worth further study.