Complications Associated With Midurethral Slings

Voiding dysfunction is a common concern after sling surgery. In contrast to the often prolonged period of incomplete bladder emptying observed after retropubic colposuspensions, spontaneous voiding is generally achieved rapidly with midurethral sling placement.[41] Urinary retention requiring catheterization occurs in 2-20% of patients, although its duration is generally limited.[41] Levin et al.[42] reported a 2.5% rate of urinary retention requiring catheterization for a period of longer than 7 days; only one patient failed to void spontaneously by 1 month after surgery. Apart from the risk of overt urinary retention, the development of either objective changes to voiding patterns or debilitating obstructive symptoms is possible after sling placement.[43-45] Klutke et al.[46] noted a 2.8% rate of obstructive symptoms that ultimately required transvaginal sling release in a series of 600 patients who underwent TVT.

The development of de novo urgency following midurethral sling placement is a concern. This symptom is reported in 0-26% of patients, and is attributed to obstructive or locally irritative causes.[41] Midurethral sling placement is, however, more likely than traditional sling procedures to alleviate preoperative urgency and irritative symptoms. For example, in one review, nearly 9% of patients required anticholinergic therapy for de novo urgency, whereas 58% of the patients (in the same cohort) who required anticholinergic drugs before surgery were able to stop this therapy after sling placement.[47] When de novo urgency does occur, it is typically treated with dietary and behavioral modification and anticholinergic therapy.

Bladder perforation is a relatively common occurrence during sling placement, seen in 1-10% of cases.[21,48] A combined experience of 92 surgeons indicated a 7% bladder perforation rate in a study population of over 12,000 patients.[49] Despite the theoretically improved control obtained through top-to-bottom passage during placement, no difference in bladder perforation rates has been noted between the use of SPARC® and TVT.[26] Unsurprisingly, however, bladder perforation rates are substantially lower with the transobturator approach, although urethral perforation has been reported.[50] Given these data, we believe that cystourethroscopy should be performed intraoperatively following sling placement, irrespective of technique.

Vascular injury and hemorrhage are arguably the most feared complications of any sling placement, despite their rarity; hemorrhagic complications have occasionally resulted in death.[51] Abouassaly et al.[52] report blood loss of greater than 250 ml in 5% and 500 ml in 3% of patients undergoing TVT, with only 2% of patients developing retropubic hematoma.[52] Few data exist on the relative frequencies of hemorrhagic complications after retropubic versus transobturator sling insertion, although reported trends seem to favor the transobturator approach. Anatomical studies in cadavers have suggested a worse vascular safety margin with an inside-out approach than with outside-in transobturator techniques.

Similarly, bowel perforation is a rare but potentially devastating complication.[53] In contrast to other types of complication, there is a definite advantage to the transobturator approach with respect to the avoidance of bowel injury.

Finally, mesh erosion and vaginal extrusion exist as notable concerns related to the use of synthetic slings. Use of polypropylene mesh has become standard, because of the increased erosion rates associated with other synthetic fibres, such as polyester.[54,55] Erosion and vaginal extrusion are seen not only with midurethral sling techniques, but also with most types of anti-incontinence and vaginal reconstructive surgeries that employ synthetic materials in general. Despite the common use of polypropylene, differences in sling characteristics, such as pore size and weave characteristics, could theoretically yield differences in erosion or extrusion rates. For example, our experience suggests an unacceptably high incidence of vaginal extrusion associated with use of ObTape®, despite its polypropylene makeup, which might be attributable to the small pore size of its mesh.[56]

Vaginal extrusion rates of 0-6% are reported.[24,26,30,50] A trend towards increased extrusion rates might be associated with the transobturator approach, although further data are needed to confirm this finding. Of importance, while erosion and extrusion can present with bleeding, pain, or recurrent incontinence, these complications may also be asymptomatic. Accordingly, a thorough postoperative examination and high index of suspicion for these sequelae is necessary following sling placement.


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