Anterior Colporrhaphy (AC) is obsolete as anti- incontinence procedure and is being mentioned to make the point that they are impossible to identify sonographically since there often is no permanent anatomical alteration. What’s worse- AC is a risk factor for ISD (Dietz und Clarke, 2001) and can trigger, unmask or worsen stress urinary incontinence. At times it appears that Kelly sutures, placed under the bladder neck at the time of an AC, can effect some kind of minor colposuspension, but to date there are no systematic studies regarding the anatomical and functional effects of AC and its variations.
Elevation and distortion of the bladder neck arising from a colposuspension is easily documented- the pathognomonic appearance after colposuspension is the ‘colposuspension ridge’ seen in Figure 1. Marked overelevation seems to be associated with postoperative voiding dysfunction and de novo or worsened urge incontinence. Such appearances may also be observed after Laparoscopic colposuspensions. A Marshall Marchetti Urethropexy, or a laparoscopic urethropexy usually results in a more acute retrovesical angle (under 90 degrees).
Fascial slings are usually seen at the level of the bladder neck, and traditional Aldridge type slings result in a complete immobilisation of the bladder neck (Figure 2). They are not as echogenic as modern polypropylene slings but can usually be detected at the level of the internal meatus or under the trigone. Often there also is obvious compression of the proximal urethra, and it is easy to see why those techniques, now fortunately obsolete, were so frequently associated with major postoperative problems.
Injectables vary greatly in their echogenicity. Collagen seems to disappear fairly fast, but synthetic substances such as Macroplastique will be visible after decades as iso- to hyperechogenic zones surrounding the urethra, similar in size and location to an artificial prostate. Unfortunately there does not seem to be a good correlation between sonographic appearance and success, although in some instances one can clearly delineate an injectable implant in unusual, unexpected locations, such as too lateral or within the bladder wall. Figure 3 shows a visually perfect Macroplastique appearance in a patient with recurrent stress incontinence. Occasionally, injectables can be a major management problem, such as with sterile abscesses after Zuidex. These appear iso- to hypoechogenic and can markedly compress the urethral lumen.
Synthetic suburethral slings such as the tensionless vaginal tape (TVT), suprapubic arc tape (SPARC), intravaginal slingplasty (IVS), Monarc and transobturator TVT (TOT) have become very popular during the last 10 years and are now the primary anti- incontinence procedures in many developed countries. These slings are not without their problems, even if biocompatibility is markedly better than for previously used synthetic slings, and they differ from each other in some important aspects. Fortunately, they are easily visible on ultrasound, as shown in Figure 5 which demonstrates a Monarc sling in the three orthogonal planes, and in a rendered volume.
The most commonly used slings such as TVT, TVT-O, Sparc and Monarc are of very similar appearance on midsagittal plane imaging (see Figure 5,6). On Valsalva the effect of such slings on the urethra, a progressive compression against the symphysis pubis, or increasing urethral kinking, is evident. This is even more obvious in the axial plane (see Video 1).
Imaging may be indicated in research, in order to determine location and function of such slings, and possibly even for assessing in vivo biomechanical characteristics. Clinically, complications such as recurrence of stress incontinence, voiding dysfunction, erosion and postoperative symptoms of the irritable bladder may benefit from imaging assessment. Often, patients will not remember the exact nature of previous incontinence or prolapse surgery, and implants may be identified in women who are not aware of their presence, let alone their type. Video 2 shows a rotational volume with 2 overlapping tapes- one a TVT, the other a Monarc.
The most useful measurement after suburethral sling placement seems to be the minimum gap between sling and symphysis pubis (Figure 7), which is strongly associated with both continence and voiding function. The tighter a sling is, the less stress urinary incontinence, and (in transobturator tapes) the less urge incontinence. On the other hand, lower pubis- tape gaps are associated with voiding dysfunction (Chantarasorn et al., 2011). Occasionally, ultrasound will graphically demonstrate mesh complications, such as an urethral perforation/ erosion in Figure 8. In such cases ultrasound can be very valuable in identifying the sling, in planning the surgical removal of the implant which at times may be rather difficult, and in follow-up.
In women in whom the sling is excessively obstructive one sometimes has to resort to sling division, and this may be quite difficult to achieve without sonographic localisation. In addition, the success of sling division can be confirmed on ultrasound, which is particularly useful if symptoms persist (Fig. 9).
Video 1: Sling movement on Valsalva as seen in the orthogonal planes and an axial rendered volume. There is progressive reduction of the gap between tape and symphysis pubis.
Video 2: Two slings made visible in a rotating rendered volume. One can identify first a v- shaped TVT and then a horizontal transobturator tape.
Figure 1: Findings after colposuspension in a patient with 2nd degree uterine prolapse and a pronounced ‘colposuspension ridge’. From: Dietz, Ultrasound Obstet Gynaecol 2004; 23: 80-92
Figure 2: Findings after Aldridge fascial sling. The location of the sling is indicated by arrows.
Figure 3: Findings after Macroplastique treatment. The hyperechogenic implant surrounds the urethra in the shape of a donut.
Figure 4: Findings in a patient with sterile abscess after Zuidex injection. The donut- shaped implant seems to cause a urethral stenosis. (Dr. S. Albrich, Mainz)
Figure 5: Findings after Monarc suburethral sing, seen in the three orthogonal planes (A-C)and in a rendered volume (D). The sling is indicated by arrows.
Figure 6: A comparison of TVT and Monarc tapes at rest (left) and on Valsalva (right). From: Dietz et al., Pelvic Floor Ultrasound. Springer London, 2007
Figure 7: Monarc sling at rest and on Valsalva. The symphysis-sling gap is shown by the two-sided arrow. S= symphysis, U=urethra, B=bladder, R= rectum, A= anal canal. The arrow demonstrates the tape- pubis gap, the most effective measure of tape ‘tightness’.
Figure 8: Urethral erosion/ perforation of a TVT tape (arrows). Half of the tape had already been removed vaginally due to obstructive symptoms.
Figure 9: Findings after tape division. The tape is invisible in the midsagittal plane and clearly interrupted in the axial plane (bottom left and right). The gap between sling ends is about 7 mm.