Introduction
Stress urinary incontinence (SUI) is a common condition in women, with a prevalence of 35.5% in urology and obstetrics and gynecology outpatient clinics in Turkey (1), similar with that in the other European countries with the rate of 35% (2).
The main goal of the surgical treatment of SUI is to restore continence with minimal morbidity. Midurethral slings (MUS) are defined and performed continuously for the treatment of female SUI. Tension-free vaginal tape (TVT), which is a minimally invasive technique, was described in 1995 by Ulmsten and Petros (3) and has been used for the treatment of SUI in women. Despite the high success rates ranging from 84% to 95% that were notified for TVT, (4,5,6,7), there are concerns regarding its operative safety. Most perioperative complications of the TVT procedure have been related to penetration into the retropubic space (8,9). Transobturator tape (TOT), which was described by Delorme et al. (10) in 2001, was adopted because of perioperative and postoperative complications of TVT.
The aim of this study was to evaluate the predictive factors that could affect the effectiveness and complication rates of MUS, which has been performed for the surgical treatment of SUI in 5 medical centers in Turkey since 1999.
Materials and Methods
In this study, we included a total of 594 women (outside to in transobturator in 285, inside to out transobturator in 91, retropubic in 218) from 5 medical centers in Turkey, who were diagnosed with urodynamic SUI and underwent a MUS operation between October 1999 and August 2011 (Table 1). The study was approved by the İstanbul University Cerrahpaşa Faculty of Medicine Local Ethics Committee (approval number: 32821). Consent form was filled out by all participants.
The median age was 53.9 (27-82) years. A postoperative follow-up period of less than 6 months was the exclusion criterion in this study.
Patients presenting with stress or mixed (stress + urgency) type urinary incontinence were evaluated with medical history, physical examination, urinalysis, urine culture, 3-day bladder diary and multichannel urodynamic studies. Provocative stress test was performed in all patients and urethral mobility and pelvic organ prolapse (POP) were evaluated. The urodynamic study consisted of uroflowmetry, measurement of post-void residual urine, 1-h pad test, cystometry and measurement of valsalva leak point pressure. Most of the urodynamic investigations in this study were performed according to the standards of International Continence Society (ICS) “Good Urodynamic Practice” after it was published (11) and the ICS terminology was used for all definitions (12). The International Consultation on Incontinence Questionnaire-Short Form (ICIQ-SF) was used as a patient reported outcome measure after the validation of the Turkish version in 2004 (13). In total, 246 of 594 women had completed ICIQ-SF.
All patients underwent retropubic or transobturator placement of midurethral slings as previously defined (1,6) either using ready to use slings or homemade meshes by experienced surgeons or residents. All patients received intravenous antibiotic at the beginning of the operation. The operations were performed under local or general anesthesia. Cystoscopy was performed in all TVT patients, however, it was done in TOT patients if there was a hematuria or any difficulties during the passage of the trocars. The catheter was removed in the evening of the operation day in TVT group and immediately after the operation in TOT group.
Two outcome measures were evaluated; subjective cure rate and complication rate. Subjective cure was defined as the statement of the women of not experiencing any loss of urine upon physical activity, coughing or sneezing. Any amount of leakage was considered as surgical failure. Reported complications were bleeding, bladder perforation, other organ injury, retention, voiding dysfunction, de novo urgency, urinary infection, pain, and skin complications.
Statistical Analysis
Statistical analysis was done to assign the factors that had a significant impact on the effectiveness and complication rates of MUS. Statistical analyses were done with SPSS version 15.0. Univariate analyses were done using chi-square test, Student’s t-test and the Mann-Whitney U test. Multivariate analyses were done using logistic regression analysis.
Results
The median follow-up period was 48 months. Patient characteristics are shown in Table 2. Preoperative evaluation findings and operative characteristics are shown in Table 3 and Table 4, respectively. Subjective cure rate was 84% and overall complication rate was 11.2%.
In univariate analysis, age, having stress incontinence (rather than mixed or urge incontinence), presence of detrussor overactivity in preoperative urodynamic investigation, use of a ready to use mesh, and concurrent POP repair were the factors that had a significant influence on the improvement of subjective cure rate (Table 5). However, number of delivery and pregnancies, comorbidity [diabetes mellitus (DM), neurologic disease], preoperative ICIQ-SF score, abdominal leak point pressure (ALPP) and experience of surgeon did not affect the subjective outcome. In multivariate analysis, increased age was a factor that negatively affected subjective cure rate and only to have a “stress type of incontinence” proved to improve cure rate (Table 6).
Univariate analysis of factors that could affect complication rate is shown in Table 7. Complication rate in the retropubic MUS patients were significantly higher compared to that in transobturator (either “inside-out” or “outside-in”) MUS patients (50/168 vs. 17/359, respectively) (p<0.001). The type of mesh used also seemed to affect complication rate in univariate analysis. The complication rate was higher in patients who were operated with homemade meshes compared to those operated with ready to use meshes (17/71 vs. 50/456, respectively) (p=0.01). In multivariate analysis, only the type of surgery proved to affect complication rate (Table 8). Table 9 shows the complications with respect to types of MUS.
Discussion
In the present study, the age of the patients and the type of incontinence were found to be independent factors affecting the cure rates of MUS in the treatment of SUI in women. There are studies assessing the risk factors affecting cure and complication rates after MUS (14,15,16). The factors that have been demonstrated to affect success following MUS procedure were the type of incontinence, previous continence surgery, age, body mass index, usage of anticholinergic medications preoperatively, concurrent prolapse surgery and the type of surgery (14,15,16).
There are several studies that demonstrated the relationship between the age of the patient and success of MUS. Chen et al. (17) reported that the success rate of transobturator MUS was greater in women aged 60 years old or younger, compared with those older than 60 years [odds ratio (OR): 11.7; 95% confidence interval (CI): 1.8-76]. Patient age was found the only statistically significant parameter affecting the cure rate in another study and the cure rate was significantly lower in TVT patients over 55 years of age (18). However, there are also several studies that have demonstrated satisfactory outcomes after TVT in elderly patients (19,20). Nonetheless, elderly is known to be a greater risk for morbidity in any surgery. In this study, the subjective cure rate was lower in elderly patients (OR: 0.97, 95% CI: 0.95-0.99, p=0.038).
Mixed urinary incontinence was found to be a significant independent predictor for failure in our study. Holmgren et al. (21) reported that the long-term (8 years) cure rate after TVT in women with mixed urinary incontinence was lower than in women with pure SUI (21). However, others have found that the presence of urge symptoms did not reduce the success rates (22,23). Existing literature showed the difference between the mixed and pure SUI, however, those studies mostly included patients who were treated with retropubic MUS (21,23). Our study included both retropubic and transobturator groups and demonstrated that to have a pure SUI improved the success rate 2.17 times (OR: 2.17, 95% CI: 1.31-3.60, p=0.002) greater than mixed incontinence. Postoperative urge incontinence remains one of the most significant reasons for patient dissatisfaction and patients with mixed urinary incontinence should be informed preoperatively about the lower cure rates.
Although the type of mesh, concurrent prolapse repair and detrussor overactivity were significant in univariant analysis, they were not affecting the outcome of the surgery significantly in multivariate analysis. Some other studies indicated these variables as independent risk factors for surgical outcome (14,15,16). In a recent study, it was reported that concomitant prolapse surgery decreased the likelihood of surgical failure after MUS (14), and that concurrent prolapse surgery, taking anticholinergic medications preoperatively and increased age were independent risk factors affecting successful outcome after MUS (16).
In the present study, number of delivery and pregnancies, comorbidity (DM, neurologic disease), ALPP, and preoperative ICIQ-SF score did not affect the surgical outcome. However, it was observed that women with an ALPP of 60 cm H2O or less had 12 times greater risk for continued SUI than women with a ALPP of more than 60 cm H2O (24). In this study, we found no relationship between ALPP and treatment outcome. Pregnancy, delivery and other conditions, such as comorbidities, have been evaluated in the literature and identified as risk factors for SUI (25), however, they were not found as independent risk factors for outcome in our study. In addition, preoperative ICIQ-SF score that revealed the degree of incontinence and quality of life of the women did not affect the surgical outcome, although 246 of 594 women had completed ICIQ-SF score sheet in this study.
The complication rate in the retropubic MUS patients was significantly higher compared to that in transobturator (either “inside out” or “outside in”) MUS patients. The type of the surgery predicts the complication rate of MUS. In addition, our study demonstrated that among the predictive factors that could affect the complication rates associated with MUS. Only the type of surgery proved to affect complication rate.
The complication rates are higher with retropubic routes than with transobturator tapes (26), although there are some studies against this conclusion (27,28,29). For instance, a randomized comparative trial suggested that patients in transobturator group had more complications than the retropubic group (27). However, in another study, it was demonstrated that TOT was equally effective as TVT with fewer complication, and the authors suggested that TOT would be the procedure of choice (30). In our opinion, the study design is important when comparing the complications rate between two groups. Minor complications included in the study (e.g. groin pain) and follow-up time could affect the complication rates of MUS. Similarly, Latthe et al. (31) reported that the rate of major complications, such as bladder injuries and haematomas, was higher in TVT than in TOT. However, groin/thigh pain and vaginal injuries were lower in TVT than in TOT (31). Additionally, operator experience may be another important factor for the complication rates. However, experience of surgeon did not affect the outcome and complication rate of the surgery in our study. Hence, most of the surgeries were performed by experienced surgeons with residents observing by experienced surgeons during the procedure in our study. In the existing literature, there are several major complications after retropubic MUS, such as nerve, bowel or major vascular injuries, pelvic hematoma, necrotizing fasciitis, ischiorectal abscess, and even death (26). Notwithstanding, the majority of complications were not reported in small randomized controlled trials. In the present study, reported complications were bleeding, bladder perforation, other organ injury, retention, voiding dysfunction, de novo urgency, urinary infection, pain, and skin complications (Table 9). The risk of complication in retropubic MUS was 6.28 (95% CI: 3.51-11.22, p<0.001) times higher than in transobturator MUS in a 48-month follow-up period.
Study Limitations
Some limitations should be pointed out with regard to our study design. The retrospective nature was the first bias of our study. Besides, this study was not a randomized trial. However, it was a multicenter study including sites throughout the country. The operations were performed by different surgeons and this point could be thought as another bias. However, the cure rate was not affected by the experience of the surgeon.
Conclusion
We conclude that age of the patient and type of incontinence were significant predictive factors affecting the cure rate for MUS in women with SUI. Risk factors for treatment failure are similar for TVT and TOT. However, retropubic approach should be considered a high risk factor for complication after MUS.
Ethics
Ethics Committee Approval: The study was approved by the İstanbul University Cerrahpaşa Faculty of Medicine Local Ethics Committee (approval number: 32821).
Informed Consent: Consent form was filled out by all participants.
Peer-review: Externally peer-reviewed.
Authorship Contributions
Surgical and Medical Practices: O.D., B.Ç., C.Özyurt, T.T., C.Ö., İ.Ş., Concept: S.Ç., O.D., C.Özyurt, C.Ö., B.Ç., Design: S.Ç., O.D., T.T., B.Ç., Data Collection or Processing: S.Ç., N.M., C.Ö., S.Çiftçi, L.İ., İ.Ş., Analysis or Interpretation: S.Ç., O.D., N.M., A.Ş., Literature Search: C.Özyurt, İ.Ş., N.M., T.T., Writing: S.Ç., N.M., T.T., O.D.
Conflict of Interest: No conflict of interest was declared by the authors.
Financial Disclosure: The authors declared that this study received no financial support.
