**3. Patient positioning**

Despite the pervasiveness, our information about the etiology and pathophysiology of female pelvic floor dysfunction is limited, as evaluation is primarily based on physical examination using international guidelines [1]. Imaging is recommended in addition, but current methods are not able to assess the effects of posture and gravity, factors recognized to impact pelvic organ position, pelvic floor muscle integrity, degree of prolapse, and symptom severity. Importantly, the degree of prolapse may be worse after a lengthy time in the upright position

The first imaging of pelvic floor dysfunction was done in the 1920s [2]. Radiological techniques were first used to show bladder manifestations and subsequently for central and posterior compartment prolapse [3]. The advent of B-mode real-time ultrasound presented a technique that allowed for a clear image by the transperineal or the vaginal route [4, 5]. Later, magnetic resonance imaging (MRI) emerged as an option. Although MRI provided imaging of ligamentous and muscular pelvic floor structures in fine detail, the cost of imaging, access problems, and restriction to imaging patients in the supine position have obstructed its general acceptance [6]. Most recently, upright open MRI has become available, which allows the patient to be imaged when sitting or standing as well as supine [7]. We have conducted research literature search that has allowed a protocol to be developed for using upright open MRI to more comprehensively evaluate patients with POP and demonstrate where posture and gravity have impact

Pelvic organ prolapse (POP) is a prevalent condition affecting up to 50% of parous women; it most often presents with symptoms of urinary incontinence [8]. Traditionally, gynecologists identify prolapse by using a simple clinical staging system (stages 0 to III or IV), with 0 indicating normal conditions and III or IV denoting full organ prolapse or vaginal eversion fOP-Q

The accuracy of staging is important, as the treatment or surgery recommended to the patient is based on the staging of their POP. However, surgical repair of prolapse has a failure rate as high as 30%, and this is probably due to current pre-surgical evaluation providing incomplete assessment of the extent of the underlying structural changes causing the prolapse, resulting in incomplete repair. For instance, the levator ani muscle complex plays an important role in pelvic organ support. Evaluation of the integrity of this element of the pelvic structures is

Physicians assess patients using guidelines from organizations such as the International Urogynecological Association (IUGA) and International Continence Society (ICS) to evaluate women for POP and define treatment options to address the associated urinary and fecal

The guidelines recommend steps for physical examination of symptomatic women which recognize that whether the patient is standing, sitting, or lying affects the position of the pelvic organs and the type, occurrence, and severity of symptoms. Hence, examination is done with

particularly difficult, and clinical examination alone is often insufficient [9].

and better when gravity is not a factor, e.g., when lying in the supine position.

on organ positions and symptom severity.

**2. Pelvic organ prolapse**

20 Pelvic Floor Disorders

staging for POP (POP-Q).

incontinence.

The relevance of posture on the extent of POP and severity of associated symptoms is well recognized. However, investigation of the influence of the body posture on pelvic floor pathologies and defecation has been done in only a few studies. Dynamic pelvic floor imaging is performed in the supine position with patients lying in a closed-configuration MR scanner [23]. The principal reason for this is the limitation on imaging to the supine position. Lying supine is also comfortable for most patients, and this technique has been simple to standardize. However, in POP, posture and gravity impact pelvic organ position, pelvic floor muscle integrity, degree of prolapse, and symptom severity. Indeed, the degree of prolapse may be worse after a lengthy time in the upright position and better when gravity is not a factor, e.g., when lying in the supine position [10]. Hence, one could question if measurement in the lying position is valid for assessment of muscle function or the evaluation of patients who are symptomatic in the standing position [24].

situations [10]. Imaging modalities employed currently include 2D and 3D ultrasound,

Effects of Posture and Gravity on Pelvic Organ Prolapse http://dx.doi.org/10.5772/intechopen.77040 23

Imaging the pelvic floor in cases of dysfunction dates back to the 1920s [2]. Radiological techniques were used first to show changes in the bladder's location within the pelvis and subsequently to demonstrate central and posterior compartment prolapse. During the 1980s the advent of B-mode real-time ultrasound allowed a clear image to be obtained by the transperi-

Translabial ultrasound can define uterovaginal prolapse [30]. The inferior border of the symphysis pubis works as a line of reference against which the higher descent of bladder, uterus, culde sac, and rectal ampulla on Valsalva maneuver can be measured [30]. Ultrasound imaging for prolapse quantification is especially helpful in outcome evaluation after pelvic reconstructive surgery, both clinically and in a research context, and it has also led to a re-appraisal

The structures used for evaluation of the three compartments are (a) the bladder neck or the leading edge of a cystocele for the anterior vaginal wall, (b) the cervix (or, within certain limitations, the pouch of Douglas) for the central compartment, and (c) the rectal ampulla for the posterior compartment. All these structures are imaged in real time in the mid-sagittal plane. An exception is a high undescended uterus that may be hidden by a rectocele [10]. Because of its non-invasive nature, ready availability, and lack of distortion, perineal or translabial ultrasound is now commonly applied in clinical practice [30], and almost all gynecologists

Current developments such as the evaluation of levator ani muscle activity and prolapse and the use of color Doppler to define urine leakage are further promoting the clinical utility of ultrasound. Hopefully, improved standardization of parameters will facilitate the ability of

Regardless of which technique is used to define descent of the pelvic organs, it is obvious that there is a large difference in pelvic organ mobility even in young nulliparous women. This difference may be partially genetic in origin. Ultrasound imaging permits quantification of the wide variation in pelvic organ mobility, which will make it easier to use molecular and population genetic approaches to assess the etiology of pelvic floor and bladder dysfunction [30].

It seems to be irrelevant with chapter title Ultrasound imaging of the pelvic floor is safer, lower in cost, and better at providing visualization of the pelvic floor structures in real time than MRI. This includes evaluation of levator function and dynamic changes during contraction and Valsalva [20]. As yet, there are no comparisons of pre- and postnatal results gained with MRI, possibly because of cost and logistic problems. However, such a comparison is

Disadvantages of ultrasound include that a large bowel-filled prolapse, i.e., an enterocele or rectocele, may cause incomplete imaging of the cervix and vault if these structures remain

available for many hundreds of women studied by 4D translabial ultrasound [2].

computed tomography, and magnetic resonance imaging.

**4.1. Ultrasound**

neal or the vaginal route [19].

of what is meant by prolapse.

and urologists are trained in its use [19].

clinicians and researchers to compare data [30].

Additionally, gravity and body weight contribute to pelvic organ muscle contractile features when standing [25]. It is likely that complex factors related to upright posture that produce more contractility over pre-loaded and/or pre-activated muscles come into play, as the weight of pelvic organs and gravity are contributing forces affecting the pelvic floor. This may explain why digital muscle testing and squeeze-pressure readings can be lower in the standing position. However, it is not known exactly which components of pelvic organ muscle activation — squeeze or lift — are influenced by alterations in posture.

Hypothetically speaking, the dynamics of the whole pelvic floor may be modified (or the squeeze and the elevation components might be influenced variously) owing to different effects such as descent of the pelvic organs when standing, different tensions on fascia and ligaments, alteration in resting length and tone of the contractile elements, and other factors.

It is well known that being upright results in a displacement of the pelvic organs and the pelvic organs muscle as compared with being supine [24, 26]. The full bladder is less mobile than the empty organ this factor may prohibit complete pelvic organ prolapse. In the standing orientation, the bladder is situated lower at rest but descends about as far in a lying patient on a Valsalva maneuver [27]. Dietz and Clarke [27] in their population of 132 patients with pelvic floor dysfunction found a 5-mm difference in the resting level of the bladder neck between supine and standing as measured by transperineal ultrasound. The only study comparing MRI in sitting and lying positions found that they were equally efficient in recognizing clinically relevant problems of the pelvic floor [28].

The position and eventual prolapse of pelvic organs is best visualized on MRI in the midsagittal plane. The imaging technique for the pelvic floor involves imaging several pelvic floor positions. Firstly, the position of the pelvic organs is assessed at rest. Then, the pelvic floor muscles images are recorded during squeezing to view the contractility and the strength of contraction of the pelvic floor. In the third phase, pelvic floor pathologies are assessed during straining and evacuation. In a recent study to view the full extent of pelvic floor pathologies, imaging was done during evacuation of a contrast agent; a number of pathologic conditions would have been missed if these defecation phase images had not been acquired [29].
