Objective
We sought to determine and compare surgical therapeutic indices (STIs) of the retropubic tension-free vaginal tape (TVT) and 2 kinds of transobturator tape (TOT), Monarc (American Medical Systems, Minneapolis, MN), and tension-free vaginal tape obturator.
Study Design
This was a retrospective cohort study. Patients with predominant stress urinary incontinence who underwent retropubic (TVT, n = 257) or TOT (n = 180) procedures were included. STIs for both groups were calculated by dividing cure by complication rate at, respectively, 2 and 12 months.
Results
Two months after surgery the STI was significantly higher after TOT whereas 12 months after surgery results of STIs were equal. The explanation is more durable cure rates and declining long-term side effects after TVT procedures.
Conclusion
Both surgical approaches seem to have their own benefits. Based on the STI, the balance between cure rate and complications is on the short term in favor of TOT but on the long term similar for TOT and retropubic TVT.
Nowadays midurethral sling (MUS) procedures are considered the gold standard for surgical treatment of female stress urinary incontinence (SUI). Due to the broad assortment of MUS procedures, it is important to choose the right surgical procedure for each individual patient.
Several studies indicated that retropubic and obturator tape procedures are equally effective in curing female SUI at 1 year after surgery. Due to small numbers, comparison of medium-term complications between studies is difficult and statistical significance is never reached. Moreover, functional complications are often not or marginally described because the primary endpoint of most studies is cure.
For preoperative counseling purposes the concept of the benefit/risk ratio is often used. Benefit is defined as cure of incontinence and risk as the potential for surgical complications. In pharmacology, the benefit/risk ratio of medication is expressed through a therapeutic index. The therapeutic index describes the ratio of desired effect to toxic effect of a certain drug. Farrell applied this concept to incontinence surgery and first described the surgical therapeutic index (STI).
The STI is defined as the ratio between the cure and complication rate. The complication rate is calculated by summing complications associated with the performed surgical procedure at a defined moment in time. The higher the STI, the safer the procedure. Urogynecologic counseling can be improved by using STIs because they are comprehensible for patients and different MUS procedures can be easily compared by using STIs.
Therefore, the aim of this study was to determine and compare STIs of the retropubic tension-free vaginal tape (TVT) and 2 kinds of transobturator tape (TOT), Monarc (American Medical Systems, Minneapolis, MN), and tension-free vaginal tape obturator (TVT-O).
Materials and Methods
Prospectively collected data from all consecutive patients undergoing TVT, Monarc, or TVT-O procedures in a large teaching hospital in The Netherlands were analyzed. Included were all patients undergoing 1 of these procedures between January 1998 and December 2006. Patients undergoing concomitant surgical procedures were excluded, as were patients who did not show up for both postoperative visits after 2 and 12 months. Selection of surgical procedures was not affected by indication for surgery.
The definitions used are according to the recommendations of the International Continence Society. A history of SUI was defined as the statement of the patient of involuntary leakage during physical activity, coughing, or sneezing. A history of urge urinary incontinence (UUI) was defined as the statement of involuntary leakage preceded by a strong sense of urgency. A history of mixed urinary incontinence (MUI) was defined as a combination of SUI and UUI. Nocturia was defined as a micturition frequency >1 during sleep. Pelvic organ prolapse was scored according to the classification of Baden and Walker.
Multichannel urodynamic investigation was performed in all patients according to the recommendations of the International Continence Society and followed by cystoscopy. During the initial visit and after the cystoscopy a cough stress test was performed in supine position. We presumed SUI to be present based on medical history combined with the positive cough stress test result in patients who demonstrated no urodynamic SUI.
The TVT (Gynecare, Ethicon Inc, Sommerville, NJ) procedure was performed as described by Ulmsten et al. The Monarc tape was inserted through the “outside-in” route, using the technique recommended by the manufacturer. TVT-O (Gynecare), an “inside-out” procedure, was performed as described by de Leval. Cystoscopy was routinely performed after all TVT procedures and only in case of bloody stained urine after TOT procedures (which did not happen).
TVT operations were carried out under local anesthesia using 0.25% prilocaine and/or systemic administered propofol. TVT-O and Monarc procedures were all performed under general anesthesia. Monarc and TVT-O procedures in this study are referred to as TOT.
Intraoperative or postoperative hemorrhage was defined as blood loss of >300 mL. Postvoid residual urine in the immediate postoperative period was defined as a postvoid residual urine of >150 mL identified by ultrasound scanning of the bladder or catheterization. Postoperative urinary retention was defined as the impossibility to void for which an indwelling catheter for >24 hours was necessary.
Follow-up of patients was at 2 and 12 months postoperatively. Urinary symptoms and other symptoms were assessed at both visits. We adhered to the recommendations of International Urogynecological Association on outcome measures. Cure of SUI was defined as the statement of the woman of not experiencing any loss of urine upon physical activity, coughing, or sneezing. Patients reporting any amount of leakage were considered failures. De novo UUI was defined as the development of postoperative UUI while absent prior to surgery. Voiding difficulty was defined as the report of difficult micturition. Furthermore, tape release, vaginal mesh erosion, dyspareunia, and groin pain were evaluated. The complication rate for the STI was calculated by summing all complications associated with the performed surgical procedure at, respectively, 2 and 12 months. STIs for both groups were calculated by dividing cure by complication rate at, respectively, 2 and 12 months. STIs were calculated for Monarc and TVT-O as 1 combined group.
A second STI was calculated based on severity of the complications. The severity factor for de novo UUI and voiding difficulty was based on the quality-of-life (QoL) analysis of the Dutch TVT database. The mean Incontinence Impact Questionnaire-7 values preoperatively, after 2 and 12 months, for patients reporting de novo UUI and voiding difficulty were analyzed. Patients with de novo UUI showed factor 2 and 4 less improvement in QoL after, respectively, 2 and 12 months compared with patients without de novo UUI. Patients with voiding difficulty showed factor 2 less improvement in QoL after 2 and 12 months compared with patients without voiding difficulty. These factors were rounded to the nearest integer to improve practical application. The factor 2 for tape release is based on common sense.
The factors were used as severity factor in the following way: the number of patients reporting de novo UUI after 2 months was multiplied by 2 and after 12 months by 4. The number of patients reporting voiding difficulty after 2 and 12 months was multiplied by 2. For tape release the severity factor was used in the same way as for voiding difficulty.
Continuous variables were compared using unpaired t test and dichotomous variables were compared using χ 2 test. Fisher exact test was used if cross tabs had a cell with an expected frequency <5. To compare dichotomous variables during time, the McNemar test was used. A P value of < .05 was considered to be statistically significant. STIs were compared by their 95% confidence intervals (CIs), after correction for bias and using accelerated nonparametric bootstrapping, drawing 1000 samples of the same size as the original sample separately for each group and with replacement. The bootstrapping approach was used to generate the 95% CIs and to use the nonoverlap of the respective CIs as a means of identifying statistically significant differences. Statistical analysis was performed using software (SPSS for Windows, Version 16.0; SPSS, Chicago, IL).
All patients were participating in prospective studies investigating the outcome of TVT (Dutch TVT database) and at a later stage the TOT (Monarc and TVT-O) as surgical treatment for female SUI. Both studies had been approved by the medical ethical committee of the St. Elisabeth Hospital Tilburg.
Results
In all, 465 patients met the inclusion criteria. A total of 28 patients (6%) did not return for any postoperative visit and were left out of this analysis. From the included patients, 37 failed to show up for the 2-month postoperative visit and 13 patients failed to show up for the 12-month postoperative visit.
Preoperative data are listed in Table 1 . This study population contains 437 patients (257 TVT, 95 Monarc, and 85 TVT-O procedures). A history of pure SUI was reported by 343 patients (78%) whereas 94 patients (22%) had a history of MUI. Anticholinergic medical treatment was given in patients with MUI before surgical treatment was considered and did not alleviate their symptoms. The majority of the patients (89%) underwent preoperative pelvic floor physiotherapy. The age of the TVT group was higher than of the TOT group and SUI during urodynamic investigation was less frequent in the TOT group ( P < .001). There were no statistically significant differences in preoperative data between patients who underwent a Monarc or TVT-O procedure (data not shown).
| Characteristic | TVT | Monarc and TVT-O | P value | ||
|---|---|---|---|---|---|
| Women, n | 257 | 180 | |||
| MEDICAL HISTORY | |||||
| Age, y | |||||
| Mean ± SD | 52 ± 11 | 49 ± 10 | .001 a , d | ||
| Type of incontinence, n | |||||
| SUI | 206 | 80% | 137 | 76% | .311 b |
| MUI | 51 | 20% | 43 | 24% | |
| Daily micturitation frequency, n | |||||
| Mean ± SD | 7 ± 2 | 8 ± 3 | .675 a | ||
| >8 | 72 | 30% | 48 | 30% | .884 b |
| Nocturia, n | |||||
| Present | 43 | 18% | 29 | 18% | .973 b |
| Previous incontinence surgery, n | |||||
| Present | 22 | 9% | 17 | 9% | .750 b |
| Previous prolapse surgery, n | |||||
| Present | 65 | 25% | 34 | 19% | .116 b |
| PHYSICAL EXAMINATION | |||||
| Cystocele, n | |||||
| ≥grade 2 | 5 | 2% | 7 | 4% | .221 b |
| Rectocele, n | |||||
| ≥grade 2 | 3 | 1% | 3 | 2% | .694 c |
| Prolapse of uterine cervix of vaginal vault, n | |||||
| ≥grade 2 | 1 | 0% | 3 | 2% | .311 c |
| URODYNAMIC INVESTIGATION | |||||
| Urodynamic stress incontinence, n | |||||
| Present | 215 | 84% | 121 | 67% | .000 b , d |
| Detrusor overactivity, n | |||||
| Present | 15 | 6% | 12 | 7% | .723 b |
Cure rates of both groups are listed in Table 2 . There were no significant differences in cure rate after 2 and 12 months. Cure rates after TVT procedures were more lasting ( P = .029).
| Variable | Total | TVT | Monarc and TVT-O | P value | ||
|---|---|---|---|---|---|---|
| Outcome | ||||||
| Cured after 2 mo | 217 | 88% | .121 a | |||
| Cured after 12 mo | 182 | 81% | ||||
| Cured after 2 mo | 147 | 83% | .029 a , d | |||
| Cured after 12 mo | 132 | 75% | ||||
| Intraoperative complications | ||||||
| Bladder perforation | 9 | 9 | 4% | 0 | 0% | .011 b , d |
| Fausse route needle introducer | 5 | 3 | 1% | 2 | 1% | 1.000 b |
| Hemorrhage | 1 | 1 | 1% | 0 | 0% | 1.000 b |
| Postoperative complications | ||||||
| >150 mL postvoid residual urine | 80 | 50 | 20% | 30 | 17% | .458 c |
| Urinary retention | 25 | 22 | 9% | 3 | 2% | .003 b , d |
| Complications after 2 mo | ||||||
| De novo UUI | 13 | 11 | 4% | 2 | 1% | .083 b |
| Voiding difficulty | 63 | 50 | 20% | 13 | 8% | .000 c , d |
| Vaginal mesh erosion | 1 | 0 | 1 | 1% | .447 b | |
| Tape release | 0 | 0 | 0 | |||
| Dyspareunia | 2 | 2 | 1% | 0 | .512 b | |
| Groin pain | 0 | 0 | 0 | |||
| Total | 79 | 63 | 26% | 16 | 9% | |
| Complications after 12 mo | ||||||
| De novo UUI | 19 | 10 | 5% | 9 | 5% | .576 c |
| Voiding difficulty | 22 | 15 | 6% | 7 | 4% | .386 b |
| Vaginal mesh erosion | 4 | 0 | 4 | 2% | .037 b , d | |
| Tape release | 7 | 5 | 2% | 2 | 1% | .473 b |
| Dyspareunia | 2 | 0 | 2 | 1% | .193 b | |
| Groin pain | 2 | 0 | 2 | 1% | .193 b | |
| Total | 56 | 30 | 13% | 26 | 15% | |
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