Pelvic Floor Ultrasound: Principles, Applications and Case Studies, 2015th Edition

6. Practical Application of Ultrasound in the Assessment of Pelvic Organ Prolapse

Vincent Tse¹ and Lewis Chan¹

(1)

Department of Urology, Concord Repatriation General Hospital, Sydney, NSW, Australia

Vincent Tse

Email: vincent.tse@sydney.edu.au

Lewis Chan (Corresponding author)

Email: lewis.chan@sswahs.nsw.gov.au

Electronic supplementary material

The online version of this chapter (doi: 10.1007/978-3-319-04310-4_6) contains supplementary material, which is available to authorized users.

Anatomy of Pelvic Organ Prolapse

Pelvic organ prolapse (POP) is a hernia of an adjacent pelvic viscus through attenuated supporting connective tissue into the vagina. Approximately one in nine women are reported to require POP surgery in their lifetime [1]. Risk factors include age, parity, prolonged second stage labour, connective tissue disorders and genetic factors such as defective collagen synthesis. A cystocele will result if the support of the anterior vaginal compartment is attenuated. A rectocele or enterorectocele will form if posterior vaginal compartment support is deficient. Apical weakness may lead to uterine prolapse, or an enterocele if the uterus is absent. Any combination of the above three areas can co-exist in any patient (Fig. 6.1). Transperineal ultrasound allows the clinician to visualize the three compartments of the pelvis in a simple and non-invasive fashion (see Chap. 5).

Fig. 6.1

Pelvic organ prolapse (POP). Weakness of the pelvic floor and supporting structures can result in POP (diagram on right) such as cystocele (orange arrow) and rectocele (blue arrow)

The Normal Female Pelvis

Figure 6.2 demonstrates the normal ultrasonic disposition of the female pelvic organs, namely, normal position of pubic symphysis, bladder, urethra, vagina, uterus, and rectum.

Fig. 6.2

(a, b) Sagittal transperineal ultrasound images demonstrating the three compartments of the pelvis. Bladder (b), urethra (u), vagina (v), rectum (r), pubic symphysis (ps), inferior/caudal (inf), superior/cranial (sup)

Practical Application of Ultrasound in Assessment of POP in Routine Clinical Practice

Although the use of pelvic ultrasound in assessing POP is not new and has been used in many academic centres in discovering and describing many anatomical defects utilizing many different research parameters [2–4], the pelvic floor reconstructive surgeon should also apply it in everyday clinical practice. One of the advantages of possessing ultrasound skills in routine clinical practice is that it can immediately add to the information which the clinician has already obtained in the history and physical examination. This advantage can come in the form of:

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2.

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Armed with this extra information immediately available at the bedside, the reconstructive surgeon can better understand the disease process behind each vaginal compartment, correlate it with the patient’s symptomatology, and thus offer a more expedited and streamlined approach to management. In cases of recurrent POP after mesh repairs, ultrasound can often help the surgeon in understanding why the particular mesh failed, and this can allow the surgeon to reflect on whether it was a technical failure which he/she can improve on in future cases. This aspect has impact on quality improvement, continued professional development, and better patient care.

Technique of Transperineal Imaging of POP and Meshes (See Tips 6.1)

As for imaging mid-urethral slings, the transducer is placed on perineum, at the introitus (see Figs. 5.2 and 5.3). The bladder should be adequately filled. Valsalva manoeuvres are then used to assess the most dependent point of the prolapse in each of the three vaginal compartments so that a POP-Q assessment (Fig. 6.3) can be possible. Slings and pelvic organ prolapse meshes should be easily identified as a hyperechoic area in their respective areas (see Case 2). Scanning position should be in both supine and standing with full bladder if preferable, and take utmost care not to cause discomfort with pressure on the introitus which may also distort anatomy. Dynamic imaging will help to elicit location of the mesh, especially in failed cases, and to assess severity of the POP and how the mesh moves with straining.

Fig. 6.3

POP-Q Quantification System (Image courtesy of American Medical Systems)

In the accompanying figure: the right side ordinates describe normal anatomical position of various points in a subject without prolapse, the left describe a patient with procidentia (i.e. total vaginal eversion)

Advances in 3D/4D Pelvic Floor Ultrasound

In recent years, 3D ultrasound has introduced another dimension to ultrasound examination of the pelvis, and one can utilized this modality to allow more detailed examination of pelvic anatomy in relation to presence of mesh, especially its location in relation to urethra, bladder, rectum, and pubic symphysis (see Chap. 9).

The following cases illustrate the application of 2D transperineal pelvic floor ultrasound in the assessment of POP in routine clinical practice:

Case 1: 65 Year Old Lady Presenting with a Symptomatic Pop-Q Stage 3 Cystocele (Video 6.1, Fig. 6.4)

Fig. 6.4

Sagittal transperineal ultrasound images of POP-Q Stage 3 cystocele at rest (left) and at maximum Valsalva (right)

Comment

This is a video clip of a transperineal ultrasound in the mid-sagittal plane, showing presentation of the cystocele from when the patient is at rest to when the patient achieves maximal Valsalva. At rest, the axis of the urethra is almost parallel to that of the vagina. The bladder is smooth in outline and there is no evidence of any intravesical lesions. There was no obvious POP evident at rest. However, as the patient starts to Valsalva, the urethral axis tilts caudally almost 90° during maximal Valsalva, and a large cystocele is seen protruding through the region of the introitus, reflecting poor lateral and central support of the bladder. The apical and posterior compartment remained relatively undisturbed during Valsalva.

Case 2: 72 Year Old Lady with Recurrent POP After a Previous Anterior Vaginal Mesh Repair and Mid-urethral Sling, Both via a Transobturator Approach (Video 6.2, Fig. 6.5)

Fig. 6.5

Transperineal ultrasound images at rest (a) and on Valsalva (b) demonstrating recurrent POP post anterior vaginal mesh repair and mid urethral sling. Mid urethral sling (s), mesh (white arrows)

Comment

This case indicates further usefulness of having an ultrasound facility at the point of consultation to expedite diagnosis. At rest, this video clip showed a synthetic midurethral sling in situ, albeit located (or possibly migrated since it was placed ) slightly more distal than the mid-urethra. The vagina is easily visible with its lumen. The mesh used in a previous transobturator cystocele repair can be seen as a curvilinear echogenicity adjacent to the bladder base. During Valsalva, (1) the mid-to-distal urethra showed dynamic compression against the sling to effect luminal coaptation; (2) the section of bladder that is adjacent to the mesh as well as the mesh itself, can be seen to move together caudad at least 1.5–2.0 cm. This significant displacement of the mesh tells us that it is no longer attached to the lateral pelvic sidewall and has failed. The most dependent point of the prolapse had protruded past the mesh and presents as a large bulge beyond the introitus with straining. There is also associated descent of the vaginal apex, approximately 3 cm from its resting position during the Valsalva. One can see that the edict of “a picture is better than a thousand words” holds true in this instance whereby her continence as well as the reasons for her recurrent POP symptoms are clearly illustrated by a simple bedside ultrasound.

Case 3: Rectocele: 68 Year Old Lady with Bulge Symptoms as Well as Constipation and Sensation of Incomplete Evacuation (Videos 6.3 and 6.4, Fig. 6.6)

Fig. 6.6

Transperineal ultrasound images of rectocele at rest (Left) and on Valsalva (right)

Comment

This video clip (Video 6.3) demonstrate the presence of a Stage 2 (POP-Q) rectocele. Fecal material is echogenic and when the patient Valsalvas, one can see bulging of the posterior vaginal wall consistent with a rectocele. This is best demonstrated with the patient standing (also see Fig. 5.4) where the prolapse is seen to reach the introitus (Video 6.4) Note that this rectocele does not appear to have caused urethral compression during abdominal straining and this patient did not have any voiding symptoms. Some larger rectoceles may present with voiding symptoms due to urethral compression which will resolve after treating the rectocele. Note that an enterocele (Fig. 6.7) was not present during straining in this patient. Together with her history and physical examination, the images also show that underlying cause of her symptoms are unlikely to be due to rectal intussusception or mucosal prolapse, but most likely due to the rectocele.

Fig. 6.7

Transperineal ultrasound image of an enterocele (arrow) presenting to the introitus in a patient with bulge symptoms. Note presence of mid-urethral sling

Tips 6.1 Protocol and Tips for Transperineal Imaging of POP

· Lighting should be dim in the examination room

· Female chaperone should be present during the examination

· Imaging is often performed in the setting of urodynamic testing or in the office with at least 200 ml of bladder volume

· Static images obtained first of the disposition of the pelvic viscera

· Dynamic images with the patient performing a Valsalva maneuver are obtained, noting bladder neck/urethra mobility, presence of urodynamic stress incontinence or occult stress incontinence after reduction of the prolapse, also note the most dependent point of the prolapse for POP-Q assessment (see below diagram for POP-Q staging)

· Avoid excessive pressure on the introitus with the transducer during the examination as it may cause discomfort, and may obscures the severity of the prolapse

· Upper tract imaging (hydronephrosis/calculi) especially in higher stage prolapse or in a patient with unexplained deterioration in renal function

· Assessment of pelvic floor contraction

· Postvoid residual measurement if done in conjunction with urodynamics

References

1.

Olsen AL, Smith VJ, Bergstrom JO, et al. Epidemiology of surgically managed pelvic organ prolapse and urinary incontinence. Obstet Gynecol. 1997;89:501–6.CrossRefPubMed

2.

Weemholf M, et al. Effect of age on levator function and morphometry of levator hiatus in women with pelvic floor disorders. Int Urogynecol J. 2010;21(9):1137–42.CrossRef

3.

Constantinou C. Dynamics of female pelvic floor function using urodynamics, ultrasound and Magnetic Resonance Imaging (MRI). Eur J Obstet Gynecol Reprod Biol. 2009;144 Suppl 1:S159–65.CrossRefPubMedCentralPubMed

4.

Huebner M, et al. Pelvic architectural distortions are due to pelvic organ prolapse. Int Urogynecol J Pelvic Floor Dysfunct. 2008;19(6):863–7.CrossRefPubMedCentralPubMed