Pelvic organ prolapse (POP) can have a large effect on a woman’s quality of life secondary to discomfort, decreased energy, and social isolation.1 In a contemporary population-based analysis, the risk of a woman undergoing surgery for prolapse by age 80 years was an estimated 13%.2 Although abdominal sacrocolpopexy is considered the gold standard operation for POP,3 the preferred approach to address coexistent stress urinary incontinence (SUI) is unclear—Burch retropubic urethropexy conveniently through the same abdominal incision or retropubic midurethral sling with a separate suburethral incision. This consideration is important given the volume of open sacrocolpopexies performed. In a study of POP procedures from 2005 to 2013, 30% of sacrocolpopexies were performed with an open abdominal approach.4
We previously conducted a randomized superiority trial comparing these anti-incontinence procedures during abdominal sacrocolpopexy.5 Although women undergoing midurethral sling reported greater satisfaction (78% vs 57%; P=.04), no difference was found in overall (midurethral sling vs Burch, 51% vs 41%; P=.30) and stress-specific continence (midurethral sling vs Burch, 74% vs 57%; P=.06) between the two treatment groups at 6-month follow-up.5 As part of a planned secondary analysis, we report continence (overall and stress-specific), voiding dysfunction, increased postvoid residual, de novo or resolution of urgency incontinence, incontinence severity, satisfaction, and adverse events at 1 and 2 years of follow-up.
MATERIALS AND METHODS
This was a planned secondary analysis of a randomized, multicenter superiority trial comparing Burch retropubic urethropexy with a retropubic midurethral sling in women with occult SUI or SUI undergoing concurrent abdominal sacrocolpopexy for symptomatic POP. The specific details of the trial have been previously published.5 The trial protocol was approved by the institutional review boards of the participating sites, was registered at ClinicalTrials.gov (NCT00934999), and is reported in accordance with the modified Consolidated Standards of Reporting Trials Statement.6 All participants provided written informed consent before enrollment.
Study-eligible women were at least 21 years of age; opted for an abdominal prolapse repair of symptomatic stage II or greater apical or anterior vaginal wall prolapse (POP quantification point Aa, Ba, or C at 1 cm or greater)7; had symptomatic stress or stress-predominant mixed urinary incontinence symptoms or occult SUI, and cystometric capacity 200 mL or greater; signed written consent; and were willing to complete follow-up visits. Follow-up assessments consisted of completion of validated questionnaires and clinical examinations at 6 weeks, 6 months, 1 year, and 2 years after the randomized surgery. For this planned secondary analysis, the primary outcomes of overall continence and stress-specific continence were assessed at 1- and 2-year follow-up. Patients were considered overall continent if they had the following criteria: 1) negative standardized cough stress test performed by an observer to whom procedures were masked, 2) no interim surgical retreatment of SUI, and 3) no self-reported urinary incontinence (ie, score of 0 on the International Consultation on Incontinence Questionnaire, Short Form).8 Stress-specific continence required fulfilling criteria 1 and 2 and having no self-reported stress-related incontinence leakage of urine (a response of never or rarely to six questions from the stress incontinence subscale of the Medical, Epidemiological, and Social Aspects of Aging questionnaire).9 Patient satisfaction, voiding dysfunction, increased postvoid residual, apical or anterior prolapse failure, de novo or resolution of urgency incontinence, and incontinence severity were assessed as secondary outcomes (see previous publication for definitions).4
All women received an abdominal sacrocolpopexy, as described by Maher et al,10 with either a Burch modified Tanagho procedure11 or a midurethral sling with a commercially available retropubic sling, as described by Ulmstein et al.12 All surgeons were fellowship-trained and had experience with both anti-incontinence surgeries. Surgeon discretion was used to determine whether a posterior repair was needed at the time of surgery.
Primary outcome analyses conducted at 1- and 2-year follow-up were performed using an intention-to-treat principle that included all randomly assigned patients; those who did not return for follow-up were considered not to be continent. A within-protocol analysis was also performed that included all patients with follow-up at the time of interest or who had interim retreatment at or before the time of interest. Demographic variables and primary and secondary outcomes were compared between the two groups using a two-sample t test for continuous variables, Wilcoxon rank-sum test for ordinal measures, and χ2 test or Fisher exact test for categorical variables. P values were two-sided and considered significant when P<.05. Statistical analyses were performed with SAS 9.3.
Women were enrolled in the study between June 1, 2009, and August 31, 2013 (Fig. 1); baseline clinical and demographic patient characteristics are summarized in Table 1. The two groups were similar in all measured baseline features, including dynamic allocation variables (ie, age, body mass index, prior incontinence surgery, intrinsic sphincter deficiency, and prolapse stage). The majority of participants were postmenopausal, white, multiparous women with greater than a high school education.
Outcome follow-up assessments were available for 51 (89%) of the 57 patients in the retropubic midurethral sling group and 47 (84%) of the 56 patients in the Burch retropubic urethropexy group at 1 year and for 48 patients (84%) in the retropubic midurethral sling group and 45 patients (80%) in the Burch retropubic urethropexy group at 2 years. Using the intention-to-treat principle, patients in the midurethral sling group had significantly higher rates of overall continence than patients in the Burch group (28/57 [49%] vs 16/56 [29%]; P=.03) at 1-year follow-up but not at 2-year follow-up (27/57 [47%] vs 18/56 [32%]; P=.10). Similar findings were observed for the within-protocol analyses. Women in the midurethral sling group had significantly higher rates of stress-specific continence than women in the Burch group at both 1-year (40/57 [70%] vs 26/56 [46%]; P=.01) and 2-year (40/57 [70%] vs 25/56 [45%]; P=.006) follow-up (Table 2).
The occurrence of each component of the composite continence primary outcome criteria at 2 years is shown in Figure 2. Most women were deemed incontinent because of a positive response to the International Consultation on Incontinence Questionnaire, Short Form question “Do you leak urine?” There was no difference between the groups in the proportion of women who had an International Consultation on Incontinence Questionnaire, Short Form score greater than 0, needed a repeat operation for SUI, had a positive stress test, or had an International Consultation on Incontinence Questionnaire, Short Form score greater than 0 and stress-specific symptoms at 2 years.
No difference was found between the two groups in patient perception of symptom improvement or incontinence severity at 2 years (Table 3). In addition, a similar proportion of patients reported satisfaction at 2 years with the midurethral sling and the Burch procedures (34/44 [77%] vs 29/42 [69%]; P=.39). Furthermore, no differences were observed between groups in the proportion of patients with apical or anterior prolapse failure, persistent voiding dysfunction, or a postvoid residual greater than 150 mL. Likewise, no difference was detected in the rate of de novo urgency incontinence, antimuscarinic medication use, or rate of resolution of baseline urgency symptoms (Table 3). Two patients in the Burch group, compared with none in the sling group, needed a reoperation for incomplete bladder emptying.
A higher proportion of women in the midurethral sling group had mesh exposure related to the abdominal sacrocolpopexy necessitating surgical revision than in the Burch group (7/56 [13%] vs 1/55 [2%]; P=.06) (two women had no postoperative visit and therefore were not included in the denominators). In addition, one sling-related mesh exposure was identified; it resolved with topical estrogen therapy. No bladder perforations occurred during retropubic midurethral sling trocar passage. The one death noted during the trial was unrelated to study participation; cause of death was complications from drug overdose.
We found that retropubic midurethral sling placement at the time of sacrocolpopexy was associated with significantly improved continence rates at 1- and 2-year follow-up compared with Burch retropubic urethropexy. This extends the findings from our previously reported multicenter superiority trial comparing the retropubic midurethral sling with the Burch procedure in women undergoing abdominal sacrocolpopexy.5 Whereas in our initial report of 6-month follow-up, we found no statistically significant difference in the rate of overall and stress-specific continence between groups,5 here we report that women undergoing retropubic midurethral sling had significantly greater stress-specific continence in the analyses of intention-to-treat and within protocol at 1- and 2-year follow-up. Similarly, women who received the sling also had greater overall continence than participants undergoing a Burch urethropexy in all analyses at 1 year. No difference was found in patient satisfaction, incontinence severity, or rate of voiding dysfunction between groups. The difference in findings between the 6-month results in our original publication5 and the 1- and 2-year results seen in the present study is likely secondary to a larger deterioration in overall and stress-specific continence rates in the Burch retropubic urethropexy group than in the retropubic midurethral sling group over time. Clinically, these findings can be used to better inform preoperative patient counseling and can aid in the selection of an anti-incontinence procedure to perform at the time of sacrocolpopexy.
A large, robustly designed, multicenter European trial comparing isolated Burch with the retropubic midurethral sling similarly found no difference in continence rates between the procedures at 6-month and 2-year follow-up.13,14 However, the trial used a less stringent primary outcome (1-hour pad test) and was underpowered because of extensive loss to follow-up in both groups at 2 years.14 In contrast, a large multicenter trial, using a similarly stringent continence composite outcome, showed that Burch yielded inferior overall success (38% vs 47%) and stress-specific continence (49% vs 66%) rates compared with an autologous pubovaginal sling at 2 years.15 This difference in overall continence persisted at 5 years.16
More recently, participants in the Stress Incontinence Surgical Treatment Efficacy trial15 and women in a large equivalence trial comparing retropubic and transobturator slings17 were pooled to compare continence rates among autologous slings, Burch, and midurethral slings (Kenton KCT, Zyczynski H, Stoddard A. Outcomes and complications of Burch, fascial, and midurethral slings [abstract]. Neurourol Urodyn 2013;32:774–5). Propensity score matching was used to minimize bias among the trials. In this analysis, the risk of failure at 2-year follow-up was 1.69 times higher for the Burch group than the midurethral sling group (95% CI 1.20–2.36) (Kenton et al, Neurourol Urodyn 2013). Moreover, women undergoing Burch were more likely to seek retreatment of SUI and reported more urgency incontinence symptoms, suggesting that the Burch may yield inferior continence results compared with a midurethral sling (Kenton et al, Neurourol Urodyn 2013).
The reason is unclear why continence after a Burch procedure would deteriorate with time. The opposing vectors for Burch (toward the anterior abdominal wall) and sacrocolpopexy (toward the sacrum) may result in diminished efficacy for Burch over time. Of note, a large multicenter equivalence trial comparing transobturator and retropubic slings noted equivalence for objective continence at 12, but not 24 or 60, months.17–19 These findings suggest that waning of efficacy with time may occur after different types of SUI operations and call for medium-term comparison studies in the future.
Although significant differences occurred in overall and stress-specific continence between groups in our study, we observed no significant differences in patient satisfaction or other secondary outcomes. Nevertheless, the direction of the comparisons consistently favored the retropubic midurethral sling, and hence these secondary outcomes may have been underpowered to reach significance at 12-month and 2-year follow-up. The overall sacrocolpopexy-related mesh exposure rate at 2 years (7.2% [8/111]) was similar to what has been previously reported in a randomized trial comparing sacrocolpopexy with and without a concomitant Burch procedure (13% [20/158]).11 Although the exposure rate was greater for the sling than the Burch group, this outcome was unrelated to the additional sling-related mesh. Only one woman had sling-related exposure, and it resolved with topical estrogen and did not require revision.
Our study had limitations. Its population was primarily postmenopausal white women from the U.S. Midwest region who underwent open abdominal sacrocolpopexy. Hence, the generalizability of our findings to more racially diverse populations or those undergoing laparoscopic or robotic sacrocolpopexy is unclear. Likewise, all surgeons in the study underwent fellowship training at the same institution, allowing for standardization of surgical techniques and postoperative care. Although this bolsters internal validity, it may limit generalizability.
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© 2018 by The American College of Obstetricians and Gynecologists. Published by Wolters Kluwer Health, Inc. All rights reserved.
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