Lewis Chan1
(1)
Department of Urology, Concord Repatriation General Hospital, Sydney, NSW, Australia
Lewis Chan
Email: lewis.chan@sswahs.nsw.gov.au
Electronic supplementary material
The online version of this chapter (doi: 10.1007/978-3-319-04310-4_5) contains supplementary material, which is available to authorized users.
The female pelvis can be imaged via transabdominal, transperineal and transvaginal approaches. There is little doubt that transvaginal imaging is the technique of choice for imaging of the pelvic organs; this is covered in Chap. 7.
Transabdominal imaging is often the initial modality of imaging in assessment of patients with voiding dysfunction. A pelvic ultrasound scan performed via the transabdominal route (Fig. 5.1) allows easy assessment of the bladder, post-void residual (PVR) urine measurements, identification of ureteric jets and general survey of female pelvic organs. There is also a role in the assessment of upper urinary tract especially in cases of voiding dysfunction or suspected neurogenic bladder.
Fig. 5.1
Transabdominal ultrasound of the pelvis (B bladder, V vagina, U uterus, R rectum)
However, in the assessment of voiding dysfunction, urinary incontinence and pelvic organ prolapse, the transperineal approach (Fig. 5.2) allows for an easy, non-invasive method of imaging the three compartments of the pelvic floor. Furthermore, there is little distortion of anatomy and patient discomfort because the transducer is placed externally. Transperineal imaging is often conducted with the patient in supine position (Fig. 5.3) but the standing position (Fig. 5.4) can be utilized and is useful for the assessment of incontinence and pelvic organ prolapse.
Fig. 5.2
Transperineal ultrasound of the pelvis (B bladder, V vagina, U uterus, R rectum, PS pubic symphysis)
Fig. 5.3
Transducer placement for transperineal (translabial) ultrasound
Fig. 5.4
Transducer placement for transperineal (translabial) ultrasound with the patient standing
Slings and synthetic meshes are easily visible as echogenic structures on ultrasound and transperineal imaging allows for good assessment especially in patients with a failed sling or complications post sling.
For most patients with voiding dysfunction, incontinence and pelvic organ prolapse, 2D imaging is sufficient but 3D imaging has an emerging role in evaluation of prolapse and meshes (see Chaps. 6 and 9).
Use of Ultrasound as the Imaging Modality for Video Urodynamics
Urodynamics are a commonly performed investigation in the evaluation of patients with voiding dysfunction and arguably remain the ‘gold standard’. Traditionally video urodynamics have utilized fluoroscopic imaging. However, not all clinicians have access to radiological equipment and there is the risk of radiation exposure to the patient and occupational exposure to the clinician, as well as the requirement to wear heavy protective garments. Furthermore, depending on the equipment, the patient may have to transfer on and off a fluoroscopy table. This poses difficulty for the elderly or patients with neurologic disease. Ultrasound imaging (by suprapubic and transperineal routes) provides an alternative imaging modality of the lower urinary tract during urodynamics (Fig. 5.5). Transperineal imaging, in particular, allows good visualization of the pelvic floor and arguably provides more information than contrast fluoroscopy in assessment of urinary incontinence and pelvic organ prolapse. This is especially the case if there is mesh or a sling present as these are easily visible on ultrasound. A protocol for using ultrasound as the imaging modality for urodynamics is attached (Tips 5.1).
Fig. 5.5
Room setup for video-urodynamics utilising ultrasound imaging (also see Chap. 3)
A Technique of Transperineal 2D Imaging (Tips 5.2)
Indications
Assessment of urinary incontinence, pelvic organ prolapse, and slings/mesh complications.
Equipment
Transperineal (translabial) 2D ultrasound can be performed using standard grayscale ultrasound equipment and the curved array transducer (e.g. 2–5 MHz) used for transabdominal imaging.
Transducer Placement
The transducer is placed on perineum in the sagittal plane (Fig. 5.3) and the image can be orientated according to the preference of the clinician (Videos 5.1 and 5.2). The key anatomic landmarks are pubic symphysis, urethra, bladder, vagina and rectum (Figs. 5.2 and 5.6).
Fig. 5.6
(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), UT uterus
Scanning Position
Patient can be scanned in the supine or standing positions. It is important to avoid excessive pressure of the transducer against the perineum that may cause discomfort and/or distort anatomy.
Movements of the Transducer
The ‘rocking’ manoeuver allows the field of view to be adjusted covering the compartment of interest (anterior, middle or posterior). It is important to adjust the depth-of-view setting to the region of interest.
Dynamic Imaging
The ability of ultrasound to obtain dynamic imaging information is an important advantage of this modality of imaging in the assessment of the pelvic floor. This should be tailored to the clinical problem, hence the importance of clinician input in performance of scans.
Dynamic assessment during transperineal ultrasound include evaluation of the bladder neck and urethral mobility, pelvic organ prolapse during Valsalva and cough, as well as pelvic floor contractions (Video 5.3). Some of these may be best performed with the patient in the standing position (Fig. 5.4). Dynamic imaging can be incorporated as part of video-urodynamics (see Case 1).
Pelvic floor ultrasound can also be used as an adjunct for pelvic floor physiotherapy. This can be performed via transabdominal or transperineal approaches and is usually performed with some urine in bladder (e.g. about 1–200 ml) but not overfilled. Dynamic 2D imaging can detect pelvic floor contraction/‘lift’ (see Video 5.4).
Clinical Cases
The following cases illustrate the utility of 2D pelvic ultrasound in the assessment of voiding dysfunction.
Case 1: Stress Urinary Incontinence
A 50-year-old female presented with symptoms of stress urinary incontinence requiring the use of two pads a day, especially when she exercised (Video 5.5 and Fig. 5.7). Stress incontinence was demonstrated during urodynamics.
Fig. 5.7
Urethral hypermobility – Transperineal ultrasound image of bladder (B) and urethra (U) at rest (left image) and with straining (right image) demonstrating rotational descent of the urethra with opening of the bladder neck/proximal urethra (arrow) leading to stress incontinence. BN bladder neck, INF inferior /caudal, SUP superior/cranial
Comments
These transperineal ultrasound images (and video captured during urodynamic study) show rotational descent with beaking and opening of the bladder neck during Valsalva and cough consistent with urethral hypermobility. This is commonly treated with placement of a mid urethral sling [1].
In the ultrasound assessment of incontinence it is often useful to perform the scan with the patient in the standing position and with at least 200 ml in the bladder to reproduce the exact situation and anatomic configuration when the patient usually experiences stress incontinence (Fig. 5.4).
Case 2: Severe Urinary Incontinence
An 80-year-old female presented with severe urinary incontinence during any activity. There was no pelvic organ prolapse on clinical examination. She requires the use of pull-up pants.
Comments
The images (Fig. 5.8) demonstrate an open bladder neck with little descent with cough or Valsalva. This finding is consistent with intrinsic urethral sphincter deficiency. Such patients have poorer results with mid-urethral synthetic slings and may be considered for a pubo-vaginal fascial sling or injection of a urethral bulking agent.
Fig. 5.8
Intrinsic urethral sphincter deficiency (ISD)- Transperineal ultrasound in a patient with severe urinary incontinence due to intrinsic urethral sphincter deficiency showing open bladder neck/proximal urethra at rest (arrow) and on Valsalva (right image). Note there is little urethral descent/mobility
Case 3: Persisting Incontinence Post Sling Procedure
A 70-year-old female with presented with persisting stress urinary incontinence following a transobturator sling procedure. She underwent urodynamic study with transperineal ultrasound imaging (Fig 5.9 and Video 5.6).
Fig. 5.9
Failed mid-urethral sling. Transperineal ultrasound in a patient with persisting urinary incontinence following mid-urethral sling surgery. Note open bladder neck/proximal urethra (arrow) due to intrinsic urethral sphincter deficiency (s sling)
Comments
The synthetic mid-urethral sling is the commonest surgical procedure worldwide for the treatment of stress urinary incontinence in women. However a proportion of patients will have suboptimal outcomes following sling surgery [1]. Possible causes of sling failure include technical reasons (sling misplacement), detrusor overactivity (either pre-existing, de-novo or secondary to obstruction) or the presence of significant urethral sphincteric deficiency (see Case 2).
Evaluation of the failed sling involves clinical examination and urodynamic assessment. Dynamic pelvic floor ultrasound has a role in evaluation of the position of the sling and urethral/bladder neck movement. The images (Fig. 5.9 and Video 5.6) illustrate an open bladder neck and proximal urethra consistent with the presence of urethral sphincter deficiency that is not corrected by the mid-urethral sling. This patient underwent injection of a bulking agent to the proximal urethra with successful coaptation of the urethra and improvement of her incontinence (Fig. 5.10 and Video 5.7).
Fig. 5.10
Post injection of bulking agent. Transperineal ultrasound in the same patient (as Fig. 5.9) following injection of bulking agent (Bulkamid®, hypoechoic area- arrow) demonstrating coaptation of the proximal urethra above the level of the sling (s)
Case 4: Recurrent Urinary Infections
A 43-year-old female presented with recurrent urinary infections following placement of a mid urethral sling 2 years previously for treatment of stress incontinence (Fig. 5.11a, b).
Fig. 5.11
(a, b) Transabdominal ultrasound of the bladder (sagittal and transverse images) demonstrating an eroded synthetic suburethral sling (arrow)
Comments
In patients with urinary infections following placement of sling or mesh it is important to exclude erosion of mesh into the bladder or urethra, and also sling obstruction with incomplete bladder emptying. In this patient transabdominal ultrasound of the pelvis showed an eroded sling in the bladder (Fig. 5.11). This was confirmed on cystoscopy and the sling segment was removed endoscopically [2].
Case 5: Voiding Dysfunction Post Sling Procedure
A 37-year-old female presented with symptoms of frequency, urgency, poor flow and incomplete bladder emptying following a retropubic mid-urethral sling procedure for stress incontinence. Transperineal ultrasound was performed to assess the sling’s position (Fig. 5.12 and Video 5.8).
Fig. 5.12
Transperineal ultrasound images in a patient with voiding dysfunction post mid-urethral sling demonstrating angulation and kinking of the urethra by the sling (right image- arrow) during Valsalva (bbladder, u urethra)
Comments
The images demonstrate angulation and kinking of the urethra by the sling during straining/Valsalva. This is a common finding in obstructive slings. The patient subsequently underwent urethrolysis with the excision of a suburethral segment of the sling leading to resolution of her voiding dysfunction [3] (Video 5.9 confirms absence of the echogenic sling material behind the urethra following excision of a suburethral segment of sling).
Case 6: Neurogenic Bladder Dysfunction
A 45-year-old female with thoracic syringomyelia presented with urinary frequency, incontinence and recurrent urinary tract infections. These images (Fig. 5.13a, b) were obtained during a urodynamic study that demonstrated the presence of reduced detrusor compliance with a detrusor leak point pressure of 47 cm H2O.
Fig. 5.13
(a, b) Neurogenic bladder. Transabdominal ultrasound images demonstrating trabeculated bladder (a) with dilated ureter (arrow) and hydronephrosis (b) with renal stone (arrow)
Comments
Ultrasound is a good modality of imaging for video urodynamic studies. Apart from assessment of the bladder and urethra, it is easy to assess dilatation of the upper urinary tracts. In assessment of the neurogenic bladder, ultrasound has an advantage over fluoroscopy, as there is no need to transfer a patient with mobility impairment to a fluoroscopy table. However, it is generally not practical to image during the voiding phase. In this case of supra-sacral neurogenic bladder the imaging demonstrated the typical complications of high bladder storage pressures with a trabeculated bladder, vesico-ureteric reflux and renal stones.
Tips 5.1 Imaging Protocol for Ultrasound Urodynamics in the Female Patient
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Tips 5.2 Tips for Transperineal Imaging
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References
1.
Fong ED, Nitti VW. Mid-urethral synthetic slings for female stress urinary incontinence. BJU Int. 2010;106(5):596–608.CrossRefPubMed
2.
Chan LW, Tse VW. Unrecognised bladder perforation while placing a suburethral synthetic sling: a minimally invasive technique for removing an intravesical sling segment. BJU Int. 2005;95(1):187–8.CrossRefPubMed
3.
Tse V, Chan L. Outlet obstruction after sling surgery. BJU Int. 2011;108 Suppl 2:24–8.CrossRefPubMed