Introduction

In 1995, Ulmsten and Petros introduced a new minimally invasive therapy for stress urinary incontinence (SUI). One such technique is the midurethral sling procedure using tension-free vaginal tape (TVT), which was developed in 1996 by Ulmsten et al. [1]. Another midurethral sling delivery system known as SPARC (suprapubic arc) was introduced in late 2001. Each system uses polypropylene mesh as the sling material. Erosion of surgical mesh materials into the genitourinary tract is a known but uncommon complication after intravaginal midurethral sling operation. The reported incidence varies from 0.3 to 23%, with lower rates with the use of autologous materials [2]. The advantages of superior strength and durability, easy availability, and versatility compared to autografts such as rectal sheath or fascia lata has to be balanced against an increased risk of infection and erosion [3]. The TVT and other wide-weave Prolene tapes have unique biomechanical characteristics. These properties may be at least partly responsible for the apparent clinical success of the implants [4]. Clemens et al. and Sweat et al. recently reported the diagnosis and management of urinary tract erosion after synthetic pubovaginal sling placement. After erosion is identified, it must be removed as soon as possible [5].

To date the TVT procedure has gained worldwide acceptance due to high rates of success and relatively low morbidity. However, there has been concern regarding the potential erosion of synthetic materials into the vagina or bladder. We describe seven patients with complications due to tape erosion into the vagina or bladder during follow-up on TVT and SPARC polypropylene mesh midurethral sling operations. We also discuss the technical aspects of how to treat these complications.

Materials and methods

Between July 1999 and July 2004, 546 patients underwent a TVT polypropylene midurethral sling operation. The first SPARC procedure for SUI was performed at our institute in January 2003, and since then until July 2004, 80 patients have received a SPARC polypropylene midurethral sling. Since January 2003, these two anti-incontinence procedures have been concurrently used in our department. During the follow-up period, a total of seven patients suffered from urogenital erosion, six with vaginal and one with bladder erosions, who were further studied. Of the six patients in the vaginal erosion group, five underwent the TVT and one the SPARC procedure. The bladder erosion patient underwent the TVT procedure. All of the patients gave informed consent, and the study protocol received the approval of the Ethics Committee of our hospital. All patients received oral estrogen replacement therapy with the exception of patients 1 and 7 without estrogen vaginal cream before surgeries. All patients received vaginal douche and antibiotics before surgery. Six patients with vaginal erosion received oral doxycycline 100 mg twice per day starting 1 day before surgery for a total of 6 days. The one bladder erosion patient was administered intravenous antibiotics with cefamezine 500 mg every 6 h and gentamicin 80 mg starting 1 day before surgery for a total of 7 days.

Patient 1 felt a rigid, rough surface over the anterior vaginal wall herself 1 month after the TVT operation with no special discomfort during intercourse for both partners. During our routine pelvic examination, a rough fibrotic band measuring about 1 cm over the right anterior vaginal wall was noted. At the 3-month follow-up, the rough fibrotic band persisted and was thus excised as requested by the patient. Patient 2 complained of a palpable rough surface over the anterior vaginal wall herself 3 months after TVT surgery. There was a visible tape about 1 cm over the right anterior vaginal wall without increasing vaginal discharge. Due to fear of progressive tape erosion, the patient decided to have the vaginal tape excised. Two patients (3 and 4) complained of a palpable vaginal rough surface and sexual discomfort by the partner like a prickly pain sensation during sexual intercourse 3 months after TVT surgeries. Pelvic examination showed visible tape and fibrotic band about 1 cm over the right anterior vaginal wall. Patient 4 requested tape removal and refused observation. Patient 3 hesitated about the tape excision and was followed for 24 months without any sequelae. Patient 5 was a heavy worker who suffered from diabetes mellitus for more than 10 years and was taking medication. She had undergone transabdominal hysterectomy and bilateral salpingo-oophorectomy 1 year previously due to bilateral tubo-ovarian abscesses. She underwent the SPARC sling procedure for pure SUI and suffered from progressive vaginal discharge and pelvic pain 1 month after the SPARC procedure. Pelvic examination showed migrated vaginal tape and erosive vaginal wall during the 3-month follow-up period. Transvaginal excision of the migrated tape with eroded vaginal wall was performed. Patient 6 had uterine myoma and SUI, and underwent concomitant TVT surgery with laparoscopically assisted vaginal hysterectomy. She felt the vagina mesh herself without other complaints or discomfort and was lost to follow-up until 7 months after the TVT operation. Under pelvic examination, a clean visible tape about 2.5 cm without vaginal wall erosion was seen over the anterior vaginal wall. Excision of the visible mesh was arranged. All of the six patients received transvaginal tape excision along with the fibrotic tissues around the mesh. During the excision, the anterior vaginal wall was dissected and the TVT tape was exposed. Excision of the exposed tape with surrounding fibrotic tissues was done followed by suture of the vaginal wall (Table 1).

Table 1 Patient characteristics. ATH abdominal total hysterectomy, VTH vaginal total hysterectomy, APC anteroposterior colporrhaphy, LAVH laparoscopically assisted vaginal hysterectomy
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Patient 7 with bladder erosion suffered from irritative bladder symptoms of frequency, urgency, urge incontinence, hematuria, and lower abdominal pain 3 weeks after the operation. This patient had bladder perforation during the TVT procedure. Cystoscopy showed TVT tape inside the bladder. Trocar reinsertion was performed and the second cystoscopy confirmed left bladder laceration (<0.5 cm) without TVT tape in the bladder. Unfortunately, she suffered from severe irritative bladder symptoms and cystoscopy was performed for the third time. Left anterior bladder wall scar formation with mesh exposed in the previous bladder perforation area was noted. Minimal laparotomy from the left suprapubic abdominal TVT wound was performed. Dissection of the anterior vaginal wall was also done to expose the TVT tape. The tape was pulled out and excised and both the anterior vaginal wall and suprapubic abdominal wall were closed. The bladder was not repaired and a three-way Foley catheter was inserted for 10 days until hematuria subsided. A combination of two antibiotics, cefamezine and gentamicin at regular dosage, was used for 7 days. The symptoms were partially resolved and the patient needed anticholinergic medications for urgency and urge incontinence symptoms.

Results

Patients 1 and 2 suffered from palpable rigid surface over the suburethral area in the vagina 1 and 3 months after TVT surgery, respectively. During the follow-up period after removal of the tape, there was no increase in vaginal discharge, no expansion of the rough surface, and no urine leakage during follow-up urodynamic examination. Patient 3 complained of her sexual partner’s discomfort 24 months after the TVT procedure without any other deteriorated symptoms during the 24-month follow-up period. After removal of the vaginal tape and fibrotic band, the urodynamic examinations in patients 3 and 4 showed no urine leakage. Patient 5 had no vaginal discharge and pelvic pain. After removal of the migrated tape and surrounding erosive vaginal wall, follow-up urodynamic examination showed no urine leakage and no other urinary symptoms (Table 2).

Table 2 Evaluation, treatment, and results
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Patient 6 suffered from palpable vaginal rough surface, and pelvic examination showed visible tape on the anterior vaginal wall without vaginal discharge. The vaginal tape erosion may have resulted from a “buttonhole” defect due to misplacement during the TVT procedure and negligence on the part of the examiner during the postoperative follow-up period. After the excision, there was no urine leakage during the follow-up urodynamic examination. The bladder erosion patient had bladder perforation during the trocar insertion of the TVT procedure. After minimal suprapubic laparotomy combined with vaginal excision of the eroded TVT tape, the symptoms subsided but were not resolved. After removal of the eroded tape at the 3-month follow-up, repeated cystoscopy showed no tape and no bladder erosion. She still complained of urgency and urge incontinence and needed anticholinergic medications to control her irritative bladder syndrome.

Discussion

The intravaginal midurethral sling operation has become an increasingly popular form of treatment for female SUI. Various materials have been described, but there is an increasing trend towards the use of macroporous materials such as polypropylene mesh. These polypropylene meshes (e.g., TVT, SPARC) are designed with a pore size larger than 75 µm to allow the admission of fibroblasts, macrophages, white blood cells, and collagen. This supports the theory that macroporous polypropylene mesh improves incorporation and decreases infection [6]. In our institution, the TVT and SPARC procedures have apparently become the most popular techniques for treatment of female SUI. Erosion is defined as the presence of foreign material within the genitourinary tract. The term “erosion” implies that the foreign body was initially present outside the genitourinary tract and gradually eroded into the bladder, urethra, or vagina [2]. The erosion rate of polypropylene mesh in our series is 7 of 626 (1.1%), which is compatible with other literature reports of 0.5% (2/404) [7], 0.9 (3/350) [8], 1.3% (4/313) [9], and 10 of 1415 patients (0.7%) [10]. Although there are several reports of mesh extrusion into the vagina and erosion into the bladder or urethra, the overall erosion rate for TVT is low at about 1%. This would appear to compare favorably with other forms of slings, which have been associated with an erosion rate of 6–12% for Gore-Tex, 4–6% for Mersilene, and 0–3% for Marlex [11]. The real mechanism of erosion is still poorly understood. In 1993, Bent et al. reported 24 patients with erosion of polytetrafluoroethylene (Teflon) suburethral slings; 23 slings were eventually removed. Histologic evaluations revealed gram-positive cocci in all expanded polytetrafluoroethylene patch interstices. Fibrous tissues, fibroblasts, and collagen were present in one-half of the specimens. It is reasonable to believe that erosions may occur in the presence of multiple factors, such as poor incorporation, infection, and excessive foreign body reaction [12]. Another cause of erosion is the rolling of the tape, causing a narrow band of synthetic material along the urethra. The resulting band can cause pressure necrosis and erosion. Possible reasons for this complication include inadequate vaginal incision suturing, wound infection, impaired wound healing, or foreign body rejection since chronic inflammation of the tape is the main cause of disturbed wound healing and vaginal erosion. The possibility of surgeon error should be considered. One theory suggests that subclinical infection of sling material results in wound separation, which may result in erosion [13]. In our experience, the symptoms of vaginal erosion include palpable roughly rigid surface on the vagina and partner discomfort during sexual intercourse. There was no severe vaginal discharge except in the diabetic patient. The irritative voiding symptoms of frequency, urgency, and urge incontinence were not found in the vaginal erosion patients. Most groups suggest that removal of the eroded tape will resolve the problem [2, 14, 15]. Kobashi et al. reported four patients with vaginal erosion of polypropylene slings who were managed conservatively with observation which resulted in completely spontaneous healing [16]. Four of our patients with a vaginal erosion area less than 1 cm were observed for 3 months and there was no vaginal epithelialization. Therefore, all of the six patients underwent transvaginal excision of the visible tape with surrounding eroded vaginal wall. In our experience, the eroded vaginal wall, the visible tape in the vagina, and the fibrotic vaginal wall should all be excised to prevent further vaginal erosion or tissue reactions. After excision of the suburethral sling, all of the six patients were continent during the follow-up interval. According to the integral theory of Ulmsten and Petros in 1995, 3 months after an intravaginal sling operation, the polypropylene mesh around the suburethral area will enhance the strength of the pubourethral ligament, suburethral vaginal wall, and paraurethral tissues. Even with excision of the suburethral sling, the urethral continence function will still be effective. In 2001, Klutke et al. reported 16 urinary retention patients after TVT procedures who underwent sling release and have remained dry by subjective report and stress test on physical examination [17].

The bladder erosion patient needs medications to control urgency and urge incontinence symptoms after removal of the exposed TVT polypropylene tape. In the operation to remove the tape, the right tape was preserved to maintain the integrity of urethral support. After observation for 3 months, the irritative voiding symptoms were not completely resolved. It is assumed that de novo detrusor instability occured after bladder erosion. We support that the complete removal of all of the polypropylene tape may be better than partial removal. We described our experience in the management of complications of tape erosion after intravaginal sling operations because most gynecologists are still not familiar with the possible complications. Therefore, we cannot definitively answer the question on the best method to treat tape erosion complications. However, if conservative treatment for more than 3 months shows no improvement or the erosion tape is more than 1 cm, tape removal should be considered.