European Urology

1. Introduction

Urinary incontinence (UI) is a very common condition, especially in women, and affects almost all aspects of everyday life, influencing not only affected individuals but also their families [1]. The prevalence of UI increases with age, with a typical rate in young adults ranging from 20% to 30%, reaching 30–40% around middle age, with a further steady increase in older age (prevalence: 30–50%) [2]. Tension-free suburethral slings revolutionized surgical treatment of female stress UI (SUI) [3]. A very short learning curve for the procedure accompanied by high clinical efficacy are the underlying causes of its current clinical usefulness [4], [5], and [6]. Although considered minimally invasive, the classical retropubic sling (tension-free vaginal tape [TVT] or TVT-like method such as IVS-02) is not devoid of intraoperative and postoperative complications, and this is the main reason for developing new, even less invasive methods of SUI surgical treatments. The following complications are commonly encountered by any clinician using the retropubic approach during midurethral tape placement: bladder and urethra perforations, postoperative difficulties in bladder emptying, retropubic hematomas, intraoperative bleeding, and wound and tape infections that can finally cause vaginal wall erosion or even tape rejection [7]. Additionally, blind insertion of the needles makes cystoscopy absolutely necessary, and this increases the risk of urinary tract infection. Therefore, the introduction into clinical practice of the transobturator route of midurethral tape insertion was very promising in the treatment of SUI [8]. The open question is whether the transobturator route of midurethral tape placement is equally effective in the treatment of female SUI, including patients with intrinsic sphincter deficiency (ISD). Therefore, the aim of our study was to examine the clinical outcomes of patients treated surgically for SUI by retropubic (IVS-02) slings or by transobturator (IVS-04) slings.

2. Methods

Consolidated Standards of Reporting Trials (CONSORT) criteria were followed for the description of this trial [9] and were approved by the local ethics committee; the patients gave informed consent. The study was conducted in the Second Department of Gynecology, Medical University of Lublin, Poland, from January 2003 to December 2005. The flow of participants through each stage of the trial is described in Fig. 1. The following criteria were used for enrollment in the study: SUI as indicated by a full clinical examination, including a complete history; standard urodynamic evaluation; urinalysis; urine culture; a complete gynecologic examination; and a cough provocation test in the supine and standing positions with a comfortably full bladder. Participants in the study were free of any other gynecologic diseases such as uterine myoma, ovarian cyst, or advanced uterine or vaginal prolapse. Only patients in grade 0 and grade 1 according to the pelvic organ prolapse-quantification scale (POP-Q) were included in the study. The POP-Q scale was used preoperatively as well as during every follow-up visit. Urodynamic studies were performed according to the International Continence Society standards. Leak-point pressures during Valsalva maneuver (VLPP) were measured. VLPP was determined at 180 ml of bladder filling. ISD was defined as VLPP of ≤60 cmH₂O. Postvoid residual volume (PVR) was measured after spontaneous micturition. The Stamey incontinence score (grade 0, continent; grade 1, loss of urine with sudden increases in abdominal pressure (coughing, sneezing, laughing); grade 2, leaks with lesser degrees of physical stress, such as walking, standing erect from a sitting position, or sitting up in bed; grade 3, total incontinence—urine is lost without any relation to physical activity or position) was used for grading the severity of SUI [10]. Finally 537 women were randomly allocated into the study. Both surgical techniques were already registered for the treatment of SUI. We used original IVS-02 (blue) and IVS-04 (green) needles and multifilament tape (type 3). The institutional review board approved the study design. All patients who were operated with IVS-02 were checked for bladder injury with cystoscopy with a 70° lens. Cystoscopy is not routinely performed during transobturator tape placement due to our clinical experience. (We routinely performed cystoscopy during our first 150 transobturator procedures, which were not included in this study, and we never encountered problems with bladder perforation; therefore, we discontinued this procedure, assuming that it was not necessary.) Simple randomization was used from pseudorandom numbers generated by a computer to allocate patients into the IVS-02 group or the IVS-04 group. Pseudorandom number means that the patients were operated on by the IVS-02 or the IVS-04 method in a ratio of 1:1. Investigators Jankiewicz and Futyma were not involved in the surgical procedures, but they were responsible for the randomization process. Some 398 patients were available for an 18-mo follow-up efficacy evaluation. Demographic and urodynamic parameters of patients in both study groups are given in Table 1 and Table 2.

Fig. 1 Flow of participants through each stage of the trial.POP-Q = pelvic organ prolapse–quantification scale; IVS-02 = retropubic arm; IVS-04 = transobturator arm.

Because the surgical instruments for each type of procedure are different, the surgeon was aware of the procedure being used, but the doctors who were conducting the follow-up visits (Jankiewicz and Futyma) were blinded with regard to the type of surgery. The surgical procedures were carried out according to the standard protocol, using a midline incision at the midurethra. After every IVS-02 surgery, cystoscopy was performed to check continuity of the bladder wall. The clinical effectiveness of each procedure was assessed using gynecologic examination and cough tests in the supine and standing positions with a comfortably full bladder, which were done on every patient during check-up in the outpatient department. The follow-up visits were scheduled for 1, 4, 6, 12, and 18 mo after surgery. Patients were considered totally cured when they were free of all SUI symptoms and cough tests in the supine and standing positions were negative. Moreover, the totally cured patients reported that the use of hygienic pads was not necessary. The operation was deemed a failure with any of the following conditions: the patient still reported urine leakage during an increase in intra-abdominal pressure; the cough test with a comfortably full bladder was positive; the woman had to use pads because of urine leakage during the day. In the improvement group, the cough test was negative but patients still experienced stress urinary leakage (much less frequently than previously) and the pads were occasionally wet. Statistical analysis was performed using Statistica v.7.1 (StatSoft, Inc., Poland). Nominal values of parameters analyzed in the nominal scale were characterized by number and percentage, whereas, in the quotient scale, they were characterized by mean, standard deviation (SD), median, lower and upper quartile, and maximal range. Based on the data from our pilot study, we calculated that each of the study groups should have at least 180 patients, assuming 75% power to calculate the clinical efficacy for both procedures with high accuracy [11]. Two-group test power analysis was calculated at 52% when p = 0.1. Analysis of nonmeasurable parameters was performed using multipartitive tables and χ² tests. When comparing two independent groups, a Mann-Whitney U test was performed; when comparing more than two groups, the Kruskall-Wallis H test and the post hoc multiple comparison were used. All statistical tests were 2-sided p tests. A 5% inference error and a p value <0.05 were considered to be statistically significant.

3. Results

Mean operation time was significantly shorter in the IVS-04 (transobturator) group (12 ± 4 min) than in the IVS-02 (retropubic) group (23 ± 5 min; p < 0.01). No bladder injury occurred in the IVS-04 group, whereas 13 intraoperational bladder perforations (6.5%) occurred in the IVS-02 group (p < 0.001). The rate of postoperative urinary retention was 3.5% (n = 7) in the IVS-04 group versus 5.0% (n = 10) in the IVS-02 group (p = 0.43). Retropubic hematoma was found postoperatively in 2.0% of patients in the IVS-02 group and in 0% of patients in the IVS-04 group (p = 0.046). The rate of tape erosions was 2.0% after retropubic sling and 2.5% after transobturator sling (p = 0.7). Other complications of retropubic slings and transobturator slings and their respective modes of treatment are given in Table 3.

After 18 mo of follow-up, 398 patients were available for clinical check-up (201 from the IVS-02 group and 197 from the IVS-04 group). Clinical effectiveness was estimated based on a subjective cure-rate scale. Only investigators Jankiewicz and Futyma were involved in the follow-up process, and they were blinded with regard to the treatment procedure used. There was no statistically significant difference in clinical efficacy between these two procedures (χ² = 1.88, p = 0.39). In the IVS-02 group, 75.1% of patients (n = 151) remained dry (cured); 16.9% of patients (n = 34) reported significant improvement; and 8.0% of patients (n = 16) were still incontinent. In the IVS-04 group, 74.1% of patients (n = 146) remained dry; 14.2% of patients (n = 28) reported significant improvement; and 11.7% of patients (n = 23) were considered to have had failed procedures.

Clinical efficacy of both midurethral slings procedures stratified against severity of SUI are shown in Table 4, Table 5, and Table 6. Statistically significant differences in cure rates between groups with different Stamey incontinence scores were found for the IVS-04 procedure and for the IVS-04 and IVS-02 groups in total. These results confirm that the transobturator sling method is less efficient compared with the retropubic sling method among patients with severe symptoms of SUI (Stamey grade 3).

Very interesting results were found when VLPP was used as differentiating parameter. The 18-mo efficacy calculated for patients operated on via the transobturator route was significantly lower when VLPP was ≤60 cmH₂O (the cut-off value for ISD). On the contrary, the retropubic sling is equally effective despite low pressure urethra (Table 7, Table 8, and Table 9).

4. Discussion

Surgery remains the cornerstone of treatment of women with a diagnosis of severe SUI and also of those who have failed to improve using conservative methods. Surgical procedures used in SUI treatment include anterior colporraphy and its various modifications, Marschall-Marchetti-Krantz and Burch colposuspension with its laparoscopic modifications, paravaginal repair, needle-suspension procedures, sling procedures (using autologous and synthetic materials), injectable agents, and artificial sphincters. However, according to expert opinion, anterior repairs with bladder buttress are the least likely of the four major operative categories (ie, anterior repair, suburethral sling, colposuspension, and long-needle suspension) to be efficacious in the long term [12]. The use of sling procedures in the treatment of stress incontinence was first described >100 yr ago, but these procedures were not very popular until the TVT was introduced into clinical practice by Petros and Ulmsten in 1995 [3]. The data presented by Novara et al in meta-analysis concerning effectiveness of tension-free midurethral slings suggest similar efficacy for retropubic tape (TVT) and transobturator tape (TVT-O), both in terms of subjective (odds ratio [OR]: 0.98; p = 0.92) and objective (OR: 0.81; p = 0.34) cure rates [13]. Moreover, comparing the TVT method with the TVT-O method, bladder perforations (p = 0.007), pelvic hematomas (p = 0.03), and bladder storage problems (p = 0.01) were significantly less common in patients treated with TVT-O [14]. At the present time, generally all suburethral sling operations follow tension-free principles, that is, tapes are placed beneath the urethra without any additional fixation. Moreover, the relatively simple technique of the operation accompanied by a rather short learning curve and a high clinical efficacy are the main reasons that the transobturator method is now the method of choice in the treatment of female SUI. Since its introduction in 2001, the transobturator out–in route of midurethral tape placement has become increasingly popular [8]. Two years later, de Leval modified this technique by introducing the inside-out technique with TVT tape [15]. General principles for both methods are almost the same, and the main reason for its introduction into practice was to maintain the high efficacy of the retropubic approach together with a marked decrease in typical complications such as bladder perforation and retropubic hematomas. In recent literature, several publications comparing these two methods of SUI treatment have been published. In our series comparing 398 patients with proven SUI, we confirmed comparable efficacy of both methods, accompanied by much shorter surgery time for the transobturator route, without a single case of bladder perforation. To the best of our knowledge this is the largest randomized study comparing the retropubic method (IVS-02) with the transobturator (IVS-04) method for SUI treatment with 18-mo of follow-up and properly calculated statistical power. Similar results comparing TVT and TVT-O were reported by Liapis et al; however, this study was much smaller [16]. They analyzed a group of 91 SUI sufferers and found that operation time was significantly shorter in the TVT-O group when compared with classical TVT, whereas blood loss was similar in both groups. Clinical effectiveness of both surgical methods was also similar (89% and 90%) in 12 mo of follow-up. Neuman reported similar comparison on the group of 150 women (75 in each group) [17]. Interestingly, in the TVT-O group he did not catheterized the bladder after operation, and he did not find any cases of postoperative urinary retention. Similar to our findings, he did not observe any bladder perforations in the TVT-O group (8% in TVT group), whereas the cure rate was the same in both analyzed groups: 90% in 12 mo of follow-up. In a recently published clinical comparison between TVT and IVS-02, tape erosions were found in 9% of patients after multifilament tape placement, with no such complications in the TVT (monofilament) group [18]. However, it has been demonstrated by Sivaslioglu in a randomized controlled trial that correct technique is essential when using a nonstretch tape. The tape should actually touch the urethra, and it should be covered with approximated vaginal hammock fascia [19]. In our study the erosion rate was <2.5% in general, with no difference between both study groups. In some patients this could be caused not by infection, but due to immunologic reasons [20]. Our trial confirmed the previously published observation that the retropubic sling is more effective among patients with ISD [21]. However, in recently published observations on 145 females, both slings were equally effective regardless of the VLPP values [22]. In contrast, the Thessaloniki group published a 12-mo follow-up of 315 women, and they concluded that both approaches showed similar high rates of cure during the first postoperative year, while complications were less common with the transobturator procedure [23].

The short-term functional outcomes, urodynamic parameters, and improvement of quality of life of patients after procedures using transobturator routes and retropubic routes were also evaluated in 88 women by Darai et al [24]. These authors concluded that retropubic routes and transobturator routes for the treatment of female SUI have equally high cure rates and equally high improvement of quality of life, but due to much lower rate of complications, the transobturator route appears to be the better option. Very similar results were published previously by Fisher et al [25], who compared their data on the first TVT and TVT-O procedures, except that patients were limited to those with SUI due to urethral hypermobility and/or due to intrinsic sphincter deficiency not showing signs of vaginal prolapse. They found that the transobturator approach seemed to be preferable in terms of efficacy and safety. Our own experiences, like reports in other literature, show that the transobturator access route is equally safe and does not require intraoperative cystoscopic control. The clinical results appear to be equivalent, in terms of recovery, to the rates obtained with classical retropubic TVT. Recently similar findings were published by Araco et al, who compared clinical efficacy of TVT versus TVT-O stratified against severity of SUI symptoms and the urodynamic evaluation (McGuire classification) [26]. After a 1-yr follow-up, they concluded that grade 2 SUI should be treated with TVT (efficacy 100%) because the efficacy of TVT-O was only 66%. Schierlitz et al also found that retropubic TVT to be a more effective operation than the transobturator tape sling operation in women with SUI and ISD [27]. In recently published data, the long-term (5-yr) TVT success rate did not depend on predictive factors at multivariate analysis; however, high body mass index, low abdominal leak-point pressure, and high-grade incontinence impaired the cure rate [28].

5. Conclusions

Both analyzed techniques of SUI treatment IVS-02 (retropubic) and IVS-04 (transobturator) are equally clinically effective in an 18-mo follow-up. Transobturator sling technique (out–in) markedly reduces intraoperational complications such as bladder perforation and retropubic hematoma. Significantly shorter surgery time without need for routine cystoscopy, accompanied by equal clinical effectiveness, makes the transobturator route the method of choice in the treatment of SUI in females. ISD might be an indication for retropubic placement of a midurethral sling.

Author contributions: Konrad Futyma had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Study concept and design: Rechberger.

Acquisition of data: Futyma, Jankiewicz.

Analysis and interpretation of data: Rechberger, Futyma, Jankiewicz.

Drafting of the manuscript: Rechberger.

Critical revision of the manuscript for important intellectual content: Skorupski, Adamiak.

Statistical analysis: Futyma, Jankiewicz.

Obtaining funding: Rechberger.

Administrative, technical, or material support: Rechberger.

Supervision: Rechberger.

Other (specify): None.

Financial disclosures: I certify that all conflicts of interest, including specific financial interests and relationships and affiliations relevant to the subject matter or materials discussed in the manuscript (eg, employment/affiliation, grants or funding, consultancies, honoraria, stock ownership or options, expert testimony, royalties, or patents filed, received, or pending), are the following: None.

Funding/Support and role of the sponsor: This study was supported by KBN (Komitet Badań Naukowych) grant no. N407 309433.

Acknowledgment statement: The authors acknowledge Medical University of Lublin for administrative support.