Introduction

The intravaginal sling (IVS Tyco Health Care UK) for treatment of stress urinary incontinence was introduced into the clinical praxis by Ulmsten and Petros [1] in 1995. Postoperative complications, e.g., erosions are described, caused by the fact that multifilament material is used for the sling’s confectioning [2–6]. Erosions into the urethra or vagina are described after using monofilament material as well [7–13]. Statistically significant differences in erosion between the monofilament (TVT) and multifilament (IVS) suburethral slings were found in favor of monofilament tapes [14, 15]. This is the first reported case of developing a urethrovaginal fistula after surgical treatment of primary stress urinary incontinence using a suburethral sling (after PubMed search using the following terms: urethrovaginal fistula, intravaginal sling, multifilament suburethral tape).

Case report

A sixty-year-old multiparous woman was referred with suppurate vaginal discharge, severe urinary incontinence grade III [16], and vague, diffuse vaginal pain seventeen months after she had undergone an IVS procedure. Her medical history showed obesity. She denied having any allergies.

The pelvic examination revealed an erosion of the sling into the vagina and a large urethrovaginal fistula bordered by granuloma (Figs. 1, 2, and 3). The urethrovaginal fistula began 0.4 cm from the external urinary meatus and extended to the bladder neck with an intact urethral sphincter. During Valsalva, a leakage of urine and after filling the bladder with a solution of indigo carmine also a leakage of the latter through the fistula appeared. The cystoscopy showed no pathological changes.

Fig. 1
figure 1

Urethrovaginal fistula after IVS placement. a Meatus urethrae externus; b urethrovaginal fistula with granuloma

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Fig. 2
figure 2

Urethrovaginal fistula after IVS placement. a tape; b urethrovaginal fistula bordered by granuloma

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Fig. 3
figure 3

Urethrovaginal fistula after IVS placement. a Foley catheter in place; b tape; c urethrovaginal fistula with granuloma

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The sling was removed and a biopsy from the border of the granuloma was taken to exclude malignancy. After primary wound healing, in a second operation, the fistula was repaired by using a vaginal flap in the following manner. First, a U-shaped anterior vaginal flap was marked so that its basis was located near the bladder neck and its tip located in the direction of the apex of the vagina. The granulomatous tissue at the edges of the urethral defect was trimmed. After that, the vaginal wall was incised at the markings. The vaginal wall and the edges of the urethra were mobilized and the vaginal flap was prepared and placed over the fistula. Using a monofilament continuous suture, the edges of the vaginal flap were sutured to the edges of the urethra. Finally, the vaginal wall was closed. The recovery period was uneventful. Three months after the corrective surgery, the patient complained about stress urinary incontinence only, confirmed by Valsalva and urodynamics (Fig. 4). A subsequent conservative treatment regime with noradrenalin–serotonin reuptake blocker (duloxetine) and pelvic floor training improved the stress urinary incontinence from grade III to grade I to the patient’s satisfaction.

Fig. 4
figure 4

Urethral pressure profile at rest and under stress. Functional length of the urethra, 21.2 mm; maximum urethral closure pressure, 115.9 cm H2O; transmission ratio in the proximal urethra, 52%; in the midurethra, 55%; and in the distal urethra, 151.0%

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Discussion

In the past decade, polypropylene slings have gained in popularity and have become the preferred technique for the treatment of stress urinary incontinence in various centers [17]. Sling tapes differ according to the type of polymer, the nature of the fibers, the weight, pore size, and porosity [18]. These differences may result in varied combinations of in vivo reactions and differences in the propensity for infection, erosion, and rejection.

The IVS Tunneller mesh is a type III material [18]. Slack et al. [19] compared the in vivo tissue responses of three available polypropylene suburethral slings that differ in fabric structure and in the size of the resulting interstices and pores. The presence of numerous, closely spaced filaments with a small diameter prevented the formation of extensive fibrous connective tissue at two slings (Obtape and IVS). Peripheral encapsulation with minimal fibrous in growth increases the risk of infection and erosion. This thesis is supported by Falconer et al. [20]. Furthermore, vaginal extrusion of the tape may be related to the surgical technique including factors related to the incision or hemostasis [19]. There are probably multiple factors in addition to the mesh material that can result in urethral erosion, e.g., forceful urethral dilatation in attempts to loosen the sling [21]. This was not the case in our patient.

Bafghi et al. [22] described in their study that among 149 patients operated with a multifilament polypropylene mesh sling (IVS), eleven patients (7.4%) had an infection in the area of the tape. The interval between the mesh implantation and the onset of the first functional signs of infection was an average of 10 months. Lim and Rane [3] reported a case of suburethral vaginal erosion and pyogenic granuloma formation 14 months after intravaginal slingplasty (IVS).

The histological examination of the granulomatous tissue surrounding the urethra–vaginal fistula showed an extensive proliferation of capillary vessels and fibroblasts with inflammatory infiltration of lymphocytes, plasmocytes, macrophages, and segmented granulocytes. It might be possible that in this case the described inflammatory reaction has lead to the erosion of the suburethral sling (IVS) into the urethra and vagina during the 17 postoperative months, followed by the development of urethra–vaginal fistula. As there is no literature regarding the development of urethra–vaginal fistulas after IVS placement, this remains speculative.

After the final surgery, the patient denied any further surgical approach. In spite of the situation, duloxetine was added to the pelvic floor exercise. Although duloxetine is suggested as the first step for the management of stress urinary incontinence [23–26], it is the first time to our knowledge that with the intake of this medication, the stress urinary incontinence improved significantly after urethral reconstruction.