Large-scale randomized trials have not only documented the efficacy of minimally invasive midurethral slings for stress urinary continence, they have also provided more adequate data on the incidence of complications. In practice, meanwhile, we are seeing more complications as the number of midurethral sling placements increases.
Often times, complications can be significantly more impactful than the original urinary incontinence. It is important to take the complications of sling placement seriously. Let patients know that their symptoms matter, and that there are ways to manage complications.
With more long-term data and experience, we have learned more about what to do, and what not to do, to prevent, diagnose, and manage the complications associated with midurethral slings. Here is my approach to the complications most commonly encountered, including bladder perforation, voiding dysfunction, erosion, pain, and recurrent stress urinary incontinence.
I will not address vascular injury in this article, but certainly, this is a surgical emergency that needs to be handled as such. As described in the February 2015 edition of Master Class on midurethral sling technique, accurate visualization toward the ipsilateral shoulder during needle passage is an essential part of preventing vascular injuries during retropubic sling placement.
Bladder perforation has consistently been shown to be significantly more common with retropubic slings than with transobturator slings. Reported incidence has ranged from 0.8% to 34% for tension-free vaginal tape (TVT) procedures, with the higher rates seen mainly in teaching institutions. Most commonly, the reported incidence is less than 10%.
Bladder perforation has no effect on the efficacy of the treatment, and no apparent long-term consequences, as long as the injury is identified. Especially with a retropubic sling, cystoscopy should be performed after both needles are placed but prior to advancing the needles all the way through the retropubic space. Simply withdrawing a needle will cause little bladder injury while retracting deployed mesh is significantly more consequential.
I recommend filling the bladder to approximately 300 cc, or to the point where you can see evidence of full distension such as flattened urethral orifices. This confirms that the bladder is under enough distension to preclude any mucosal wrinkles or folds that can hide a trocar injury.
The first step upon recognition of a perforation is to stay calm. In the vast majority of cases, simply withdrawing the needle, replacing it, and verifying correct replacement will prevent any long-term consequences. On the other hand, you must be fully alert to the possibility that the needle wandered away from the pubic bone, and consequently may have entered a space such as the peritoneum. Suspicion for visceral injury should be increased.
Resist the temptation to replace the needle more laterally. This course correction is often an unhelpful instinct, because a more lateral replacement will not move the needle farther from the bladder; it will instead bring it closer to the iliac vessels. Vascular injuries resulting from the surgeon’s attempts at needle replacement are unfortunate, as a minor complication becomes a major one. The key is to be as distal as possible – as close to the pubic bone as possible – and not to replace the needles more laterally.
Postoperative drainage for 1-2 days may be considered, but there is nothing in the literature to require this, and many surgeons do not employ any sort of extra catheterization after surgery where perforation has been observed.
Some degree of voiding dysfunction is not uncommon in the short term, but when a patient is still unable to void normally or completely after several days, an evaluation is warranted. As with bladder perforation, reported incidence of voiding dysfunction has varied widely, from 2% to 45% with the newer midurethral slings. Generally, the need for surgical revision is about 2%.
There are two reasons for urinary retention: Insufficient contraction force in the bladder or too much resistance. If retention persists beyond a week – in the 7-10 day postop time period – I assess whether the problem is resulting from too much obstruction from the sling, some form of hypotonic bladder, other surgery performed in conjunction with sling placement, medications, or something else.
Difficulty in passing a small urethra catheter in the office may indicate excessive obstruction, for instance, and there may be indications on vaginal examination or through cystoscopy that the sling is too tight. A midurethral “speed bump,” or elevation at the midpoint, with either catheterization or the scope is consistent with over-correction.