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Repeat Surgical Intervention for Stress Urinary Incontinence after a Failed Mid Urethral Sling
urologypracticejournal.com
Repeat Surgical Intervention for Stress Urinary Incontinence after a Failed Mid Urethral Sling Blayne Welk*,y and Jennifer Winick-Ng From the Department of Surgery and Epidemiology and Biostatistics, Western University (BW) and Institute for Clinical Evaluative Sciences (BW, JW-N), London, Ontario, Canada
Abstract
Abbreviations and Acronyms
Introduction: We determined the incidence of stress urinary incontinence surgery performed after mid urethral sling procedures and the impact of physician volume on mid urethral sling failure.
CIHI = Canadian Institutes for Health Information
Methods: Administrative data were used to identify all women who underwent a mid urethral sling procedure in Ontario, Canada between 2002 and 2013. The primary outcome was subsequent stress urinary incontinence surgery. The primary exposure was surgeon mid urethral sling case volume with high volume defined as greater than the 75th percentile.
CIHI-DAD/SDS = CIHI Discharge Abstract Database and Same Day Surgeries
Results: A total of 59,556 women with a median age of 52 years (IQR 45e63) received a mid urethral sling, of whom 3.3% underwent additional stress urinary incontinence operations. The most common secondary surgery was a repeat mid urethral sling in 78.3% of cases and a pubovaginal sling in 5.8%. The cumulative incidence of repeat stress urinary incontinence surgery at 10 years of followup was 5.2% (95% CI 4.9e5.5). On multivariable survival analysis the effect of surgeon mid urethral sling volume on subsequent stress urinary incontinence surgery was nonsignificant (HR 0.89, 95% CI 0.76e1.03). Younger patient age, lower comorbidity and simultaneous hysterectomy decreased the hazard of future stress urinary incontinence surgery. In this cohort 1,425 women (2.4%) required surgical revision or removal of the initial mid urethral sling, of whom 215 (15%) underwent a simultaneous or subsequent incontinence procedure. The most common procedure was still a mesh sling, which was placed in 159 women (74.0%).
ICES = Institute for Clinical Evaluative Sciences
Submitted for publication August 5, 2015. No direct or indirect commercial incentive associated with publishing this article. The corresponding author certifies that, when applicable, a statement(s) has been included in the manuscript documenting institutional review board, ethics committee or ethical review board study approval; principles of Helsinki Declaration were followed in lieu of formal ethics committee approval; institutional animal care and use committee approval; all human subjects provided written informed consent with guarantees of confidentiality; IRB approved protocol number; animal approved project number. Supported by an Ontario Ministry of Health and Long-Term Care annual grant (ICES) and an Academic Medical Organization of Southwestern Ontario operating grant (ICES Western). 2352-0779/16/36-475/0 UROLOGY PRACTICE Ó 2016 by AMERICAN UROLOGICAL ASSOCIATION EDUCATION
AND
SD = standardized difference SUI = stress urinary incontinence
The opinions, results and conclusions are those of the authors and no endorsement by ICES, Ontario Ministry of Health and Long-Term Care or Academic Medical Organization of Southwestern Ontario is intended or should be inferred. Parts of this material are based on data and information compiled and provided by CIHI. However, the analyses, conclusions, opinions and statements expressed herein are those of the authors and not necessarily those of CIHI. * Correspondence: Division of Urology, Western University, Room B4-667, St Joseph’s Health Care, 268 Grosvenor St., London, Ontario N6A 4V2, Canada (telephone: 519 646-6367; FAX: 519 646-6037; e-mail address: [email protected]). y Financial interest and/or other relationship with Astellas.
RESEARCH, INC.
http://dx.doi.org/10.1016/j.urpr.2015.10.004 Vol. 3, 475-480, November 2016 Published by Elsevier
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Repeat Incontinence Surgery after Mid Urethral Sling
Conclusions: Secondary stress urinary incontinence surgery after mid urethral sling placement was observed in 3.3% of women. The majority of women with recurrent incontinence were treated with a repeat mid urethral sling. There is a nonsignificant trend toward higher mid urethral sling provider volume being correlated with a reduced risk of future stress urinary incontinence surgery. Key Words: urethra; suburethral slings; urinary incontinence, stress; reoperation; Canada
Large cross-sectional surveys have estimated that more than 40% of women experience at least occasional SUI.1 There has been a general increase in operative interventions for female SUI in the last 30 years.2 A claims based study using data from 2007 to 2011 estimated that by age 80 years 14% of women will have undergone SUI surgery.3 There are several different options for surgical intervention but the dominant procedure is the mid urethral sling.4 While initial mid urethral sling case series and a Cochrane meta-analysis demonstrated excellent objective cure rates of 80% to 90%,5 randomized trials with strict definitions of success suggest a more modest success rate of 55% to 60%.6 There is a recognized failure rate of mid urethral slings with time. Data from randomized, controlled trials suggest that noticeable SUI develops in at least 10% of women after 5 years.7,8 In addition, a small subset of women will have complications from the mid urethral sling, such as mesh erosion into the urethra or vagina, chronic pain, urethral fistula or voiding dysfunction.9 These patients often require surgical removal of the mid urethral sling and they may then have recurrent incontinence.9 A patient with a failed mid urethral sling represents a new and growing subset of patients with SUI. There are few guidelines available on the management of stress incontinence in these women and no randomized clinical trials to provide an objective assessment of different interventions.10 Groups have advocated several approaches, including colposuspension,11 a repeat mid urethral sling,12 autologous fascial slings13 and bulking agents.14 Surveys of surgeons have shown significant practice variability.11 The primary objective of this study was to use administrative data to assess the incidence and type of SUI procedures performed after an index mid urethral sling procedure and examine the effect of mid urethral sling provider volume on the probability of future SUI surgery. The secondary objective was to assess the incidence and type of SUI procedures performed in the subset of women in whom a mid urethral sling complication required removal or revision.
April 1, 2002 and December 31, 2013 in Ontario, Canada. The entire population of approximately 13 million people has access to a universal health care system, allowing us to consider this a population based sample. This study was done according to a prespecified protocol. The research ethics board at Sunnybrook Hospital, Toronto, Ontario, approved this study. Data Sources
We used 3 linked databases for our study, including 1) CIHI-DAD/SDS databases for hospital based diagnostic and procedural information, 2) OHIP (Ontario Health Insurance Plan) for physician claims and 3) RPDB (Registered Persons Database) for demographic information. These data sets were linked using unique encoded identifiers and analyzed at the ICES Western site. The databases are essentially complete for all study variables. The accuracy of these databases has been previously described and they are valid and reliable.15 Patient Cohort
CCI (Canadian Classification of Health Intervention) codes from CIHI-DAD/SDS were used to identify the cohort of women who underwent a mid urethral sling procedure (supplementary Appendix 1, http://urologypracticejournal. com/). The date of this procedure was considered the index date. Patients were censored at death, emigration from the province (no health care contact for 12 months), end of study (March 31, 2014) or at the occurrence of the primary outcome. Our study exclusion criteria were age younger than 18 years (8 women), not residing in Ontario (40 women), previously operated on for SUI in the 5 years prior to the index date (1,057 women) and missing institutional identity number (491 women). To address the question of management of SUI after a mid urethral sling complication we created a subcohort of patients who underwent surgical revision or removal of the mid urethral sling.15 We measured the frequency of our primary outcome in this subgroup.
Methods Study Design and Setting
Primary Outcome
We performed a population based, retrospective cohort study of all women who received a mid urethral sling between
We used CIHI-DAD/SDS CCI codes to identify subsequent SUI surgery in our cohort (supplementary Appendix 2,
Repeat Incontinence Surgery after Mid Urethral Sling
http://urologypracticejournal.com/). Codes were classified into categories, including bulking agents, a repeat mid urethral sling, other mesh slings (for example, bladder neck slings), retropubic suspensions (such as Burch colposuspension), pubovaginal slings and bladder neck reconstruction.
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considered significant. The Cochrane-Armitage test for linear trends was used to assess for significant changes in the 1-year event rate with time. Results Baseline Characteristics
Exposures and Covariates
Our primary exposure was the yearly surgeon volume of mid urethral slings at the time of index mid urethral sling implantation. We hypothesized that patients of low volume mid urethral sling providers would be more likely to require subsequent SUI surgery. Surgeon volume was determined for each year in our study period using physician identifiers in CIHI-DAD/SDS. We considered high volume surgeons as being in greater than the 75th percentile of mid urethral sling implanters in a given year. They could move between high and low volume categories with time. Secondary exposures of interest were surgeon specialty (urology, obstetrics/gynecology or unknown) and a history of a high risk feature prior to the index mid urethral sling (a binary variable indicating a previous urinary fistula, urethral diverticulum, urethral injury or pelvic radiation). Other covariates were patient age, obesity (body mass index greater than 40 kg/m2), diabetes, combined hysterectomy or pelvic organ prolapse repair, provincial region, academic or community hospital, rural residence, comorbidity, socioeconomic status and health care utilization in the year prior to the mesh SUI procedure. For comorbidity health care utilization was used as a proxy for overall health with data obtained from ADG (Aggregated Diagnostic GroupsÔ) resource utilization bands from the validated Johns Hopkins Adjusted Clinical GroupsÒ Case-Mix System.16 For socioeconomic status data we used ON-Marg (Ontario Marginalization Index), a measure of regional marginalization, which served as a proxy for individual socioeconomic status.17
Statistical Analysis
We reported frequencies (counts) or medians with the IQR. Differences in baseline characteristics of patients in whom the initial mid urethral sling performed by a high or low volume surgeon were assessed using SDs, which identify clinically meaningful differences (SD greater than 10%) better than p values.18 Our primary analysis was a multivariable survival analysis performed using robust standard error estimates to account for patient clustering within surgeons using PROC PHREG in SASÒ, version 9.4. Results are reported as the HR and 95% CIs with p <0.05
We identified 59,556 women who underwent a mid urethral sling procedure during the almost 12-year study period. A total of 310,143 person-years of followup were available and median followup was 4.9 years (IQR 2.7e7.5). Median patient age was 52 years (IQR 45e63) years, and 1,913 (3.2%) and 1,340 patients (2.2%) were censored due to death and emigration, respectively. The supplementary table (http://urologypracticejournal. com/) shows cohort demographics. Women who received the initial mid urethral sling from a high volume surgeon were significantly less likely to undergo simultaneous hysterectomy (11.7% vs 16.3%, SD 13%) and significantly more likely to have the procedure done at an academic/teaching hospital (28.8% vs 16.4%, SD 30%). In terms of health care utilization high volume surgeons saw patients significantly less in the year before surgery (median visits 2 vs 3, SD 26%) and were significantly more likely to perform urodynamics (41.8% vs 32.4%, SD 20%). A total of 1,042 surgeons performed these operations during the study period. Primary Analysis
Overall 1,958 women (3.3%) underwent repeat SUI surgery after the initial mid urethral sling procedure. A total of 2,142 incontinence procedures were performed and 1,811 of 1,958 women (92.5%) underwent only 1 additional procedure. Median time to this procedure was 1.7 years (IQR 0.8e3.9). The most frequent repeat SUI procedures were a mid urethral sling in 1,679 cases (78.3%), a pubovaginal sling in 124 (5.8%), retropubic suspension in 116 (5.4%), another mesh sling in 101 (4.7%), a bulking agent in 114 (5.3%) and bladder neck repair in 8 (0.4%). Figure 1 shows the cumulative incidence rate of a secondary SUI procedure. At 10 years it reached 5.2% (95% CI 4.9e5.5). The first repeat incontinence procedure was performed by the same surgeon who placed the mid urethral sling in 1,039 of 1,958 cases (53.1%). To assess whether the likelihood of secondary SUI surgery changed with time a 1-year event rate was created and each patient was assigned to one of the fiscal years of our study based on surgery date. There was a significant decrease in the proportion of patients who underwent repeat incontinence surgery in this first year from 1.51% in 2002 to 0.6% in 2012
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Repeat Incontinence Surgery after Mid Urethral Sling
Table. Multivariable survival analysis to assess patient and provider risk factors associated with repeat SUI surgery after index mid urethral sling HR (95% CI)
Figure 1. Cumulative incidence of SUI surgery after index mid urethral sling procedure. Bars indicate 95% CI around data points.
(Cochrane-Armitage test for trend p <0.01, supplementary Appendix 3, http://urologypracticejournal.com/). For our primary exposure of surgeon volume we found that patients of high volume surgeons and low volume surgeons did not significantly differ in the primary outcome of secondary SUI surgery. For high volume surgeons the rate was 3.2% (1,399 of 43,611 cases) for an event rate of 6.1/1,000 person-years and for low volume surgeons the rate was 3.5% (559 of 15,945 cases) for an event rate of 6.9/ 1,000 person-years (chi-square test p ¼ 0.07). Figure 2 shows the distribution of yearly surgeon volumes during the study period. On multivariable survival analysis the surgeon volume of mid urethral slings did not significantly impact the need for secondary SUI surgery (HR 0.89, 95% CI 0.76e1.03, see table). Similarly, surgeon specialty and prior high risk features were not significant predictors of future SUI surgery. Higher comorbidity levels increased the chance of
Surgeon vol (referent high vol) Surgeon: Urologist Gynecologist Unknown High risky Age/10-yr increase ADG Resource Utilization Band (referent 0/1, healthy user) Obesity Diabetes Simultaneous hysterectomy Simultaneous pelvic organ prolapse surgery Ontario Marginalization Index: Dependency Deprivation Ethnic concentration Instability Academic/teaching hospital
0.89 (0.76e1.03)
p Value* 0.12
1.00 0.93 0.50 1.11 0.94 1.23
(referent) (0.75e1.16) (0.21e1.18) (0.36e3.37) (0.90e0.99) (1.15e1.32)
e 0.53 0.11 0.86 <0.01 <0.01
0.91 0.97 0.79 0.99
(0.72e1.15) (0.84e1.13) (0.63e0.97) (0.85e1.16)
0.42 0.73 0.03 0.91
1.02 1.00 0.98 1.00 0.92
(0.97e1.06) (0.96e1.04) (0.94e1.02) (0.96e1.04) (0.75e1.13)
0.51 0.82 0.24 0.97 0.42
*Provincial region p <0.01 (data not shown). y History of fistula, diverticulum, radiation or urethral injury.
secondary SUI surgery (HR 1.23, 95% CI 1.15e1.32) and simultaneous hysterectomy (HR 0.79, 95% CI 0.63e0.97) while younger age decreased the chance of secondary SUI surgery (HR 0.94, 95% CI 0.90e0.99). There was significant regional variation in the province.
Secondary Analysis
Our secondary objective was to evaluate the use of secondary incontinence procedures after a patient had undergone surgical removal or revision of the mid urethral sling. We identified 1,425 of 59,556 patients (2.4%) who required removal or revision of the mid urethral sling.15 Of these 1,425 women 215 (15.1%) underwent a second incontinence operation simultaneously with removal/revision of the mid urethral sling (84 of 215 or 39.1%) or in the future (131 of 215 or 60.9%). The 215 women had a median followup of 4.6 years (IQR 2.4e7.1). Of these 215 patients 203 (94%) underwent a single subsequent procedure. The first repeat procedure was a mid urethral or other mesh sling in 159 women (74.0%), a pubovaginal sling in 42 (19.5%) or another operation such as retropubic suspension, a bulking agent or bladder neck repair in 26 (12.1%).
Discussion Figure 2. Yearly mid urethral sling procedure volumes during study period. Median number to be considered high volume at greater than 75th percentile was 17 procedures per year.
Despite the complications associated with vaginal mesh, mid urethral slings are considered a standard surgical option
Repeat Incontinence Surgery after Mid Urethral Sling
for female SUI.19 While efficacy has been well assessed in randomized clinical trials, objective and subjective failure rates do not correlate well with patient dissatisfaction.7,8 One of the more absolute measures of patient dissatisfaction is the proportion of women who undergo a secondary SUI procedure. This captures patients with continued or recurrent SUI and those with significant bother, and it represents a definitive failure of the mid urethral sling procedure. We found that among a large group of women who had a mid urethral sling 3.3% underwent subsequent SUI surgery with a cumulative incidence of 5.2% after 10 years of followup. Overall our results are similar to the 4% to 10% reported after a variety of SUI procedures.20e23 Of the women who underwent re-treatment for SUI 82% underwent a repeat mid urethral sling procedure, which is in keeping with general operative patterns,4 practice pattern surveys11 and studies from other countries.22 While this practice is common, it is concerning that it is based only on expert opinion and case series,12,24 and may be associated with an increased risk of mesh complications.15 The significant decrease in early reoperation for recurrent SUI that we observed during our study period likely reflects a shift toward a more conservative practice pattern in mid urethral sling cases as well as the discontinuation of collagen as a bulking agent in Canada in 2010. Although there appeared to be a trend toward a significant volume-outcome relationship between placement of the index mid urethral sling and subsequent SUI surgery, it was not statistically significant. This is in contrast to a robust volume-outcome relationship that we previous noted between mid urethral sling implantation volume and subsequent surgery for mid urethral sling complications.15 This difference is likely due to the increased complexity of mid urethral sling failures. Appropriate initial patient selection, type of mid urethral sling procedure, postoperative patient activities, patient expectations and the surgeon approach to the failed mid urethral sling patient all influence the chance of procedural failure. Not all of these factors are necessarily related to a technically sound procedure. Similar to other administrative data studies21 and a secondary analysis of the SISTEr (Stress Incontinence Surgical Treatment Efficacy) Trial, which examined pubovaginal slings and retropubic suspensions,25 younger age was associated with decreased SUI reoperation. This is likely due to differences in tissue quality at surgery and the numerous age related changes to bladder and sphincter function.25 We also found that simultaneous hysterectomy was associated with a lower risk of future incontinence surgery, which again was previously identified.20,26 This may be due to a beneficial change to the mechanics of the pelvic floor or because some of these slings may have been
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placed prophylactically. The increased risk of recurrent SUI surgery with more comorbidities may be due to more complex incontinence and altered healing. Regional variation has been demonstrated in the delivery of stress incontinence surgery.27 In our study it was likely a result of differences in physician density and a large geographic area with variable population densities. Approximately 1 of 7 women who underwent removal or revision of a mid urethral sling also underwent simultaneous or subsequent SUI surgery. While the practice pattern of repeat mid urethral sling placement in the reoperation cohort as a whole was not surprising, the fact that mesh based slings (bladder neck or mid urethral slings) were used predominately in this subgroup of patients was unexpected. AUA (American Urological Association) guidelines suggest that mid urethral slings should be avoided in patients with prior mesh complications.28 While there may be specific clinical circumstances when this practice is appropriate, which we were unable to evaluate given the limitations of administrative data, we would have expected a higher proportion of pubovaginal slings, which have been described in this challenging population.13 This administrative data study was performed using data from a universal health care system, which ensures complete capture of all procedures. Furthermore, a low emigration rate allows for complete and long-term followup of the population. In Ontario patients require a referral from a physician to see a specialist and there are no limitations on patient referrals or restrictions on which specialist they see. This ensures equitable accessibility of our study population to repeat SUI procedures. Limitations of administrative data should be acknowledged. Clinical characteristics, such as the degree of incontinence or the specific type of mid urethral sling, cannot be determined. In addition, one must accept a degree of misclassification in the data. While we excluded patients treated with SUI procedures in the 5 years before the first mid urethral sling, it is likely that a small proportion of our cohort underwent other SUI procedures prior to this. As with any observational study, our comparison of high and low volume surgeons may have residual confounders that were not measurable with our data sources. Finally, it is important to note that the actual rate of recurrent SUI after an index mid urethral sling is likely higher, given that many women may not elect to undergo repeat treatment. Conclusions
There is an increase in repeat SUI surgery after an index mid urethral sling from 1.2% at 1 year to 5.2% at 10 years. The risk of a patient undergoing repeat SUI surgery is not
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Repeat Incontinence Surgery after Mid Urethral Sling
significantly influenced by the surgeon yearly volume of mid urethral slings. However, healthier, younger patients and those undergoing simultaneous hysterectomy were significantly less likely to have a second SUI procedure. Surgeons predominately used mid urethral slings to manage recurrent SUI and predominately used mesh based procedures even after removal or revision of the initial mid urethral sling.
References 1. Coyne KS, Sexton CC, Thompson CL et al: The prevalence of lower urinary tract symptoms (LUTS) in the USA, the UK and Sweden: results from the Epidemiology of LUTS (EpiLUTS) study. BJU Int 2009; 104: 352. 2. Oliphant SS, Wang L, Bunker CH et al: Trends in stress urinary incontinence inpatient procedures in the United States, 1979-2004. Am J Obstet Gynecol 2009; 200: 521.e1. 3. Wu JM, Matthews CA, Conover MM et al: Lifetime risk of stress urinary incontinence or pelvic organ prolapse surgery. Obstet Gynecol 2014; 123: 1201. 4. Chughtai BI, Elterman DS, Vertosick E et al: Midurethral sling is the dominant procedure for female stress urinary incontinence: analysis of case logs from certifying American Urologists. Urology 2013; 82: 1267. 5. Rapp DE and Kobashi KC: The evolution of midurethral slings. Nat Clin Pract Urol 2008; 5: 194. 6. Richter HE, Albo ME, Zyczynski HM et al: Retropubic versus transobturator midurethral slings for stress incontinence. N Engl J Med 2010; 362: 2066. 7. Kenton K, Stoddard AM, Zyczynski H et al: 5-year longitudinal followup after retropubic and transobturator mid urethral slings. J Urol 2015; 193: 203. 8. Laurikainen E, Valpas A, Aukee P et al: Five-year results of a randomized trial comparing retropubic and transobturator midurethral slings for stress incontinence. Eur Urol 2014; 65: 1109. 9. Blaivas JG, Purohit RS, Weinberger JM et al: Salvage surgery after failed treatment of synthetic mesh sling complications. J Urol 2013; 190: 1281. 10. Bakali E, Buckley BS, Hilton P et al: Treatment of recurrent stress urinary incontinence after failed minimally invasive synthetic suburethral tape surgery in women. Cochrane Database Syst Rev 2013; 2: CD009407. 11. Giarenis I, Thiagamoorthy G, Zacchè M et al: Management of recurrent stress urinary incontinence after failed midurethral sling: a survey of members of the International Urogynecological Association (IUGA). Int Urogynecol J 2015; 26: 1285. 12. Pradhan A, Jain P and Latthe PM: Effectiveness of midurethral slings in recurrent stress urinary incontinence: a systematic review and meta-analysis. Int Urogynecol J 2012; 23: 831.
13. Milose JC, Sharp KM, He C et al: Success of autologous pubovaginal sling after failed synthetic mid urethral sling. J Urol 2015; 193: 916. 14. Lee HN, Lee YS, Han JY et al: Transurethral injection of bulking agent for treatment of failed mid-urethral sling procedures. Int Urogynecol J 2010; 21: 1479. 15. Welk B, Al-Hothi H and Winick-Ng J: Removal or revision of vaginal mesh used for the treatment of stress urinary incontinence. JAMA Surg 2015; 150: 1. 16. Austin PC, van Walraven C, Wodchis WP et al: Using the Johns Hopkins Aggregated Diagnosis Groups (ADGs) to predict mortality in a general adult population cohort in Ontario, Canada. Med Care 2011; 49: 932. 17. Matheson FI, Dunn JR, Smith KL et al: Development of the Canadian Marginalization Index: a new tool for the study of inequality. Can J Public Health, suppl., 2012; 103: S12. 18. Austin PC: Using the standardized difference to compare the prevalence of a binary variable between two groups in observational research. Commun Stat Simul Comput 2009; 38: 1228. 19. Nager C, Tulikangas P, Miller D et al: Position statement on mesh midurethral slings for stress urinary incontinence. Female Pelvic Med Reconstr Surg 2014; 20: 123. 20. Fialkow M, Symons RG and Flum D: Reoperation for urinary incontinence. Am J Obstet Gynecol 2008; 199: 546.e1. 21. Jonsson Funk M, Siddiqui NY, Kawasaki A et al: Long-term outcomes after stress urinary incontinence surgery. Obstet Gynecol 2012; 120: 83. 22. Wu MP, Long CY, Liang CC et al: Trends in reoperation for female stress urinary incontinence: a nationwide study. Neurourol Urodyn 2014; 34: 693. 23. Abdel-Fattah M, Familusi A, Fielding S et al: Primary and repeat surgical treatment for female pelvic organ prolapse and incontinence in parous women in the UK: a register linkage study. BMJ Open 2011; 1: e000206. 24. Fenner A: Incontinence: sling when you’re winning-determining the value of repeat surgery after failed midurethral sling. Nat Rev Urol 2012; 9: 672. 25. Richter HE, Goode PS, Brubaker L et al: Two-year outcomes after surgery for stress urinary incontinence in older compared with younger women. Obstet Gynecol 2008; 112: 621. 26. Duru C, Jha S and Lashen H: Urodynamic outcomes after hysterectomy for benign conditions: a systematic review and metaanalysis. Obstet Gynecol Surv 2012; 67: 45. 27. Suskind AM, Kaufman SR, Dunn RL et al: Population-based trends in ambulatory surgery for urinary incontinence. Int Urogynecol J 2013; 24: 207. 28. Dmochowski RR, Blaivas JM, Gormley EA et al: Update of AUA guideline on the surgical management of female stress urinary incontinence. J Urol 2010; 183: 1906.
Repeat Surgical Intervention for Stress Urinary Incontinence after a Failed Mid Urethral Sling Blayne Welk*,y and Jennifer Winick-Ng From the Department of Surgery and Epidemiology and Biostatistics, Western University (BW) and Institute for Clinical Evaluative Sciences (BW, JW-N), London, Ontario, Canada
Abstract
Abbreviations and Acronyms
Introduction: We determined the incidence of stress urinary incontinence surgery performed after mid urethral sling procedures and the impact of physician volume on mid urethral sling failure.
CIHI = Canadian Institutes for Health Information
Methods: Administrative data were used to identify all women who underwent a mid urethral sling procedure in Ontario, Canada between 2002 and 2013. The primary outcome was subsequent stress urinary incontinence surgery. The primary exposure was surgeon mid urethral sling case volume with high volume defined as greater than the 75th percentile.
CIHI-DAD/SDS = CIHI Discharge Abstract Database and Same Day Surgeries
Results: A total of 59,556 women with a median age of 52 years (IQR 45e63) received a mid urethral sling, of whom 3.3% underwent additional stress urinary incontinence operations. The most common secondary surgery was a repeat mid urethral sling in 78.3% of cases and a pubovaginal sling in 5.8%. The cumulative incidence of repeat stress urinary incontinence surgery at 10 years of followup was 5.2% (95% CI 4.9e5.5). On multivariable survival analysis the effect of surgeon mid urethral sling volume on subsequent stress urinary incontinence surgery was nonsignificant (HR 0.89, 95% CI 0.76e1.03). Younger patient age, lower comorbidity and simultaneous hysterectomy decreased the hazard of future stress urinary incontinence surgery. In this cohort 1,425 women (2.4%) required surgical revision or removal of the initial mid urethral sling, of whom 215 (15%) underwent a simultaneous or subsequent incontinence procedure. The most common procedure was still a mesh sling, which was placed in 159 women (74.0%).
ICES = Institute for Clinical Evaluative Sciences
Submitted for publication August 5, 2015. No direct or indirect commercial incentive associated with publishing this article. The corresponding author certifies that, when applicable, a statement(s) has been included in the manuscript documenting institutional review board, ethics committee or ethical review board study approval; principles of Helsinki Declaration were followed in lieu of formal ethics committee approval; institutional animal care and use committee approval; all human subjects provided written informed consent with guarantees of confidentiality; IRB approved protocol number; animal approved project number. Supported by an Ontario Ministry of Health and Long-Term Care annual grant (ICES) and an Academic Medical Organization of Southwestern Ontario operating grant (ICES Western). 2352-0779/16/36-475/0 UROLOGY PRACTICE Ó 2016 by AMERICAN UROLOGICAL ASSOCIATION EDUCATION
AND
SD = standardized difference SUI = stress urinary incontinence
The opinions, results and conclusions are those of the authors and no endorsement by ICES, Ontario Ministry of Health and Long-Term Care or Academic Medical Organization of Southwestern Ontario is intended or should be inferred. Parts of this material are based on data and information compiled and provided by CIHI. However, the analyses, conclusions, opinions and statements expressed herein are those of the authors and not necessarily those of CIHI. * Correspondence: Division of Urology, Western University, Room B4-667, St Joseph’s Health Care, 268 Grosvenor St., London, Ontario N6A 4V2, Canada (telephone: 519 646-6367; FAX: 519 646-6037; e-mail address: [email protected]). y Financial interest and/or other relationship with Astellas.
RESEARCH, INC.
http://dx.doi.org/10.1016/j.urpr.2015.10.004 Vol. 3, 475-480, November 2016 Published by Elsevier
476
Repeat Incontinence Surgery after Mid Urethral Sling
Conclusions: Secondary stress urinary incontinence surgery after mid urethral sling placement was observed in 3.3% of women. The majority of women with recurrent incontinence were treated with a repeat mid urethral sling. There is a nonsignificant trend toward higher mid urethral sling provider volume being correlated with a reduced risk of future stress urinary incontinence surgery. Key Words: urethra; suburethral slings; urinary incontinence, stress; reoperation; Canada
Large cross-sectional surveys have estimated that more than 40% of women experience at least occasional SUI.1 There has been a general increase in operative interventions for female SUI in the last 30 years.2 A claims based study using data from 2007 to 2011 estimated that by age 80 years 14% of women will have undergone SUI surgery.3 There are several different options for surgical intervention but the dominant procedure is the mid urethral sling.4 While initial mid urethral sling case series and a Cochrane meta-analysis demonstrated excellent objective cure rates of 80% to 90%,5 randomized trials with strict definitions of success suggest a more modest success rate of 55% to 60%.6 There is a recognized failure rate of mid urethral slings with time. Data from randomized, controlled trials suggest that noticeable SUI develops in at least 10% of women after 5 years.7,8 In addition, a small subset of women will have complications from the mid urethral sling, such as mesh erosion into the urethra or vagina, chronic pain, urethral fistula or voiding dysfunction.9 These patients often require surgical removal of the mid urethral sling and they may then have recurrent incontinence.9 A patient with a failed mid urethral sling represents a new and growing subset of patients with SUI. There are few guidelines available on the management of stress incontinence in these women and no randomized clinical trials to provide an objective assessment of different interventions.10 Groups have advocated several approaches, including colposuspension,11 a repeat mid urethral sling,12 autologous fascial slings13 and bulking agents.14 Surveys of surgeons have shown significant practice variability.11 The primary objective of this study was to use administrative data to assess the incidence and type of SUI procedures performed after an index mid urethral sling procedure and examine the effect of mid urethral sling provider volume on the probability of future SUI surgery. The secondary objective was to assess the incidence and type of SUI procedures performed in the subset of women in whom a mid urethral sling complication required removal or revision.
April 1, 2002 and December 31, 2013 in Ontario, Canada. The entire population of approximately 13 million people has access to a universal health care system, allowing us to consider this a population based sample. This study was done according to a prespecified protocol. The research ethics board at Sunnybrook Hospital, Toronto, Ontario, approved this study. Data Sources
We used 3 linked databases for our study, including 1) CIHI-DAD/SDS databases for hospital based diagnostic and procedural information, 2) OHIP (Ontario Health Insurance Plan) for physician claims and 3) RPDB (Registered Persons Database) for demographic information. These data sets were linked using unique encoded identifiers and analyzed at the ICES Western site. The databases are essentially complete for all study variables. The accuracy of these databases has been previously described and they are valid and reliable.15 Patient Cohort
CCI (Canadian Classification of Health Intervention) codes from CIHI-DAD/SDS were used to identify the cohort of women who underwent a mid urethral sling procedure (supplementary Appendix 1, http://urologypracticejournal. com/). The date of this procedure was considered the index date. Patients were censored at death, emigration from the province (no health care contact for 12 months), end of study (March 31, 2014) or at the occurrence of the primary outcome. Our study exclusion criteria were age younger than 18 years (8 women), not residing in Ontario (40 women), previously operated on for SUI in the 5 years prior to the index date (1,057 women) and missing institutional identity number (491 women). To address the question of management of SUI after a mid urethral sling complication we created a subcohort of patients who underwent surgical revision or removal of the mid urethral sling.15 We measured the frequency of our primary outcome in this subgroup.
Methods Study Design and Setting
Primary Outcome
We performed a population based, retrospective cohort study of all women who received a mid urethral sling between
We used CIHI-DAD/SDS CCI codes to identify subsequent SUI surgery in our cohort (supplementary Appendix 2,
Repeat Incontinence Surgery after Mid Urethral Sling
http://urologypracticejournal.com/). Codes were classified into categories, including bulking agents, a repeat mid urethral sling, other mesh slings (for example, bladder neck slings), retropubic suspensions (such as Burch colposuspension), pubovaginal slings and bladder neck reconstruction.
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considered significant. The Cochrane-Armitage test for linear trends was used to assess for significant changes in the 1-year event rate with time. Results Baseline Characteristics
Exposures and Covariates
Our primary exposure was the yearly surgeon volume of mid urethral slings at the time of index mid urethral sling implantation. We hypothesized that patients of low volume mid urethral sling providers would be more likely to require subsequent SUI surgery. Surgeon volume was determined for each year in our study period using physician identifiers in CIHI-DAD/SDS. We considered high volume surgeons as being in greater than the 75th percentile of mid urethral sling implanters in a given year. They could move between high and low volume categories with time. Secondary exposures of interest were surgeon specialty (urology, obstetrics/gynecology or unknown) and a history of a high risk feature prior to the index mid urethral sling (a binary variable indicating a previous urinary fistula, urethral diverticulum, urethral injury or pelvic radiation). Other covariates were patient age, obesity (body mass index greater than 40 kg/m2), diabetes, combined hysterectomy or pelvic organ prolapse repair, provincial region, academic or community hospital, rural residence, comorbidity, socioeconomic status and health care utilization in the year prior to the mesh SUI procedure. For comorbidity health care utilization was used as a proxy for overall health with data obtained from ADG (Aggregated Diagnostic GroupsÔ) resource utilization bands from the validated Johns Hopkins Adjusted Clinical GroupsÒ Case-Mix System.16 For socioeconomic status data we used ON-Marg (Ontario Marginalization Index), a measure of regional marginalization, which served as a proxy for individual socioeconomic status.17
Statistical Analysis
We reported frequencies (counts) or medians with the IQR. Differences in baseline characteristics of patients in whom the initial mid urethral sling performed by a high or low volume surgeon were assessed using SDs, which identify clinically meaningful differences (SD greater than 10%) better than p values.18 Our primary analysis was a multivariable survival analysis performed using robust standard error estimates to account for patient clustering within surgeons using PROC PHREG in SASÒ, version 9.4. Results are reported as the HR and 95% CIs with p <0.05
We identified 59,556 women who underwent a mid urethral sling procedure during the almost 12-year study period. A total of 310,143 person-years of followup were available and median followup was 4.9 years (IQR 2.7e7.5). Median patient age was 52 years (IQR 45e63) years, and 1,913 (3.2%) and 1,340 patients (2.2%) were censored due to death and emigration, respectively. The supplementary table (http://urologypracticejournal. com/) shows cohort demographics. Women who received the initial mid urethral sling from a high volume surgeon were significantly less likely to undergo simultaneous hysterectomy (11.7% vs 16.3%, SD 13%) and significantly more likely to have the procedure done at an academic/teaching hospital (28.8% vs 16.4%, SD 30%). In terms of health care utilization high volume surgeons saw patients significantly less in the year before surgery (median visits 2 vs 3, SD 26%) and were significantly more likely to perform urodynamics (41.8% vs 32.4%, SD 20%). A total of 1,042 surgeons performed these operations during the study period. Primary Analysis
Overall 1,958 women (3.3%) underwent repeat SUI surgery after the initial mid urethral sling procedure. A total of 2,142 incontinence procedures were performed and 1,811 of 1,958 women (92.5%) underwent only 1 additional procedure. Median time to this procedure was 1.7 years (IQR 0.8e3.9). The most frequent repeat SUI procedures were a mid urethral sling in 1,679 cases (78.3%), a pubovaginal sling in 124 (5.8%), retropubic suspension in 116 (5.4%), another mesh sling in 101 (4.7%), a bulking agent in 114 (5.3%) and bladder neck repair in 8 (0.4%). Figure 1 shows the cumulative incidence rate of a secondary SUI procedure. At 10 years it reached 5.2% (95% CI 4.9e5.5). The first repeat incontinence procedure was performed by the same surgeon who placed the mid urethral sling in 1,039 of 1,958 cases (53.1%). To assess whether the likelihood of secondary SUI surgery changed with time a 1-year event rate was created and each patient was assigned to one of the fiscal years of our study based on surgery date. There was a significant decrease in the proportion of patients who underwent repeat incontinence surgery in this first year from 1.51% in 2002 to 0.6% in 2012
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Repeat Incontinence Surgery after Mid Urethral Sling
Table. Multivariable survival analysis to assess patient and provider risk factors associated with repeat SUI surgery after index mid urethral sling HR (95% CI)
Figure 1. Cumulative incidence of SUI surgery after index mid urethral sling procedure. Bars indicate 95% CI around data points.
(Cochrane-Armitage test for trend p <0.01, supplementary Appendix 3, http://urologypracticejournal.com/). For our primary exposure of surgeon volume we found that patients of high volume surgeons and low volume surgeons did not significantly differ in the primary outcome of secondary SUI surgery. For high volume surgeons the rate was 3.2% (1,399 of 43,611 cases) for an event rate of 6.1/1,000 person-years and for low volume surgeons the rate was 3.5% (559 of 15,945 cases) for an event rate of 6.9/ 1,000 person-years (chi-square test p ¼ 0.07). Figure 2 shows the distribution of yearly surgeon volumes during the study period. On multivariable survival analysis the surgeon volume of mid urethral slings did not significantly impact the need for secondary SUI surgery (HR 0.89, 95% CI 0.76e1.03, see table). Similarly, surgeon specialty and prior high risk features were not significant predictors of future SUI surgery. Higher comorbidity levels increased the chance of
Surgeon vol (referent high vol) Surgeon: Urologist Gynecologist Unknown High risky Age/10-yr increase ADG Resource Utilization Band (referent 0/1, healthy user) Obesity Diabetes Simultaneous hysterectomy Simultaneous pelvic organ prolapse surgery Ontario Marginalization Index: Dependency Deprivation Ethnic concentration Instability Academic/teaching hospital
0.89 (0.76e1.03)
p Value* 0.12
1.00 0.93 0.50 1.11 0.94 1.23
(referent) (0.75e1.16) (0.21e1.18) (0.36e3.37) (0.90e0.99) (1.15e1.32)
e 0.53 0.11 0.86 <0.01 <0.01
0.91 0.97 0.79 0.99
(0.72e1.15) (0.84e1.13) (0.63e0.97) (0.85e1.16)
0.42 0.73 0.03 0.91
1.02 1.00 0.98 1.00 0.92
(0.97e1.06) (0.96e1.04) (0.94e1.02) (0.96e1.04) (0.75e1.13)
0.51 0.82 0.24 0.97 0.42
*Provincial region p <0.01 (data not shown). y History of fistula, diverticulum, radiation or urethral injury.
secondary SUI surgery (HR 1.23, 95% CI 1.15e1.32) and simultaneous hysterectomy (HR 0.79, 95% CI 0.63e0.97) while younger age decreased the chance of secondary SUI surgery (HR 0.94, 95% CI 0.90e0.99). There was significant regional variation in the province.
Secondary Analysis
Our secondary objective was to evaluate the use of secondary incontinence procedures after a patient had undergone surgical removal or revision of the mid urethral sling. We identified 1,425 of 59,556 patients (2.4%) who required removal or revision of the mid urethral sling.15 Of these 1,425 women 215 (15.1%) underwent a second incontinence operation simultaneously with removal/revision of the mid urethral sling (84 of 215 or 39.1%) or in the future (131 of 215 or 60.9%). The 215 women had a median followup of 4.6 years (IQR 2.4e7.1). Of these 215 patients 203 (94%) underwent a single subsequent procedure. The first repeat procedure was a mid urethral or other mesh sling in 159 women (74.0%), a pubovaginal sling in 42 (19.5%) or another operation such as retropubic suspension, a bulking agent or bladder neck repair in 26 (12.1%).
Discussion Figure 2. Yearly mid urethral sling procedure volumes during study period. Median number to be considered high volume at greater than 75th percentile was 17 procedures per year.
Despite the complications associated with vaginal mesh, mid urethral slings are considered a standard surgical option
Repeat Incontinence Surgery after Mid Urethral Sling
for female SUI.19 While efficacy has been well assessed in randomized clinical trials, objective and subjective failure rates do not correlate well with patient dissatisfaction.7,8 One of the more absolute measures of patient dissatisfaction is the proportion of women who undergo a secondary SUI procedure. This captures patients with continued or recurrent SUI and those with significant bother, and it represents a definitive failure of the mid urethral sling procedure. We found that among a large group of women who had a mid urethral sling 3.3% underwent subsequent SUI surgery with a cumulative incidence of 5.2% after 10 years of followup. Overall our results are similar to the 4% to 10% reported after a variety of SUI procedures.20e23 Of the women who underwent re-treatment for SUI 82% underwent a repeat mid urethral sling procedure, which is in keeping with general operative patterns,4 practice pattern surveys11 and studies from other countries.22 While this practice is common, it is concerning that it is based only on expert opinion and case series,12,24 and may be associated with an increased risk of mesh complications.15 The significant decrease in early reoperation for recurrent SUI that we observed during our study period likely reflects a shift toward a more conservative practice pattern in mid urethral sling cases as well as the discontinuation of collagen as a bulking agent in Canada in 2010. Although there appeared to be a trend toward a significant volume-outcome relationship between placement of the index mid urethral sling and subsequent SUI surgery, it was not statistically significant. This is in contrast to a robust volume-outcome relationship that we previous noted between mid urethral sling implantation volume and subsequent surgery for mid urethral sling complications.15 This difference is likely due to the increased complexity of mid urethral sling failures. Appropriate initial patient selection, type of mid urethral sling procedure, postoperative patient activities, patient expectations and the surgeon approach to the failed mid urethral sling patient all influence the chance of procedural failure. Not all of these factors are necessarily related to a technically sound procedure. Similar to other administrative data studies21 and a secondary analysis of the SISTEr (Stress Incontinence Surgical Treatment Efficacy) Trial, which examined pubovaginal slings and retropubic suspensions,25 younger age was associated with decreased SUI reoperation. This is likely due to differences in tissue quality at surgery and the numerous age related changes to bladder and sphincter function.25 We also found that simultaneous hysterectomy was associated with a lower risk of future incontinence surgery, which again was previously identified.20,26 This may be due to a beneficial change to the mechanics of the pelvic floor or because some of these slings may have been
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placed prophylactically. The increased risk of recurrent SUI surgery with more comorbidities may be due to more complex incontinence and altered healing. Regional variation has been demonstrated in the delivery of stress incontinence surgery.27 In our study it was likely a result of differences in physician density and a large geographic area with variable population densities. Approximately 1 of 7 women who underwent removal or revision of a mid urethral sling also underwent simultaneous or subsequent SUI surgery. While the practice pattern of repeat mid urethral sling placement in the reoperation cohort as a whole was not surprising, the fact that mesh based slings (bladder neck or mid urethral slings) were used predominately in this subgroup of patients was unexpected. AUA (American Urological Association) guidelines suggest that mid urethral slings should be avoided in patients with prior mesh complications.28 While there may be specific clinical circumstances when this practice is appropriate, which we were unable to evaluate given the limitations of administrative data, we would have expected a higher proportion of pubovaginal slings, which have been described in this challenging population.13 This administrative data study was performed using data from a universal health care system, which ensures complete capture of all procedures. Furthermore, a low emigration rate allows for complete and long-term followup of the population. In Ontario patients require a referral from a physician to see a specialist and there are no limitations on patient referrals or restrictions on which specialist they see. This ensures equitable accessibility of our study population to repeat SUI procedures. Limitations of administrative data should be acknowledged. Clinical characteristics, such as the degree of incontinence or the specific type of mid urethral sling, cannot be determined. In addition, one must accept a degree of misclassification in the data. While we excluded patients treated with SUI procedures in the 5 years before the first mid urethral sling, it is likely that a small proportion of our cohort underwent other SUI procedures prior to this. As with any observational study, our comparison of high and low volume surgeons may have residual confounders that were not measurable with our data sources. Finally, it is important to note that the actual rate of recurrent SUI after an index mid urethral sling is likely higher, given that many women may not elect to undergo repeat treatment. Conclusions
There is an increase in repeat SUI surgery after an index mid urethral sling from 1.2% at 1 year to 5.2% at 10 years. The risk of a patient undergoing repeat SUI surgery is not
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Repeat Incontinence Surgery after Mid Urethral Sling
significantly influenced by the surgeon yearly volume of mid urethral slings. However, healthier, younger patients and those undergoing simultaneous hysterectomy were significantly less likely to have a second SUI procedure. Surgeons predominately used mid urethral slings to manage recurrent SUI and predominately used mesh based procedures even after removal or revision of the initial mid urethral sling.
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13. Milose JC, Sharp KM, He C et al: Success of autologous pubovaginal sling after failed synthetic mid urethral sling. J Urol 2015; 193: 916. 14. Lee HN, Lee YS, Han JY et al: Transurethral injection of bulking agent for treatment of failed mid-urethral sling procedures. Int Urogynecol J 2010; 21: 1479. 15. Welk B, Al-Hothi H and Winick-Ng J: Removal or revision of vaginal mesh used for the treatment of stress urinary incontinence. JAMA Surg 2015; 150: 1. 16. Austin PC, van Walraven C, Wodchis WP et al: Using the Johns Hopkins Aggregated Diagnosis Groups (ADGs) to predict mortality in a general adult population cohort in Ontario, Canada. Med Care 2011; 49: 932. 17. Matheson FI, Dunn JR, Smith KL et al: Development of the Canadian Marginalization Index: a new tool for the study of inequality. Can J Public Health, suppl., 2012; 103: S12. 18. Austin PC: Using the standardized difference to compare the prevalence of a binary variable between two groups in observational research. Commun Stat Simul Comput 2009; 38: 1228. 19. Nager C, Tulikangas P, Miller D et al: Position statement on mesh midurethral slings for stress urinary incontinence. Female Pelvic Med Reconstr Surg 2014; 20: 123. 20. Fialkow M, Symons RG and Flum D: Reoperation for urinary incontinence. Am J Obstet Gynecol 2008; 199: 546.e1. 21. Jonsson Funk M, Siddiqui NY, Kawasaki A et al: Long-term outcomes after stress urinary incontinence surgery. Obstet Gynecol 2012; 120: 83. 22. Wu MP, Long CY, Liang CC et al: Trends in reoperation for female stress urinary incontinence: a nationwide study. Neurourol Urodyn 2014; 34: 693. 23. Abdel-Fattah M, Familusi A, Fielding S et al: Primary and repeat surgical treatment for female pelvic organ prolapse and incontinence in parous women in the UK: a register linkage study. BMJ Open 2011; 1: e000206. 24. Fenner A: Incontinence: sling when you’re winning-determining the value of repeat surgery after failed midurethral sling. Nat Rev Urol 2012; 9: 672. 25. Richter HE, Goode PS, Brubaker L et al: Two-year outcomes after surgery for stress urinary incontinence in older compared with younger women. Obstet Gynecol 2008; 112: 621. 26. Duru C, Jha S and Lashen H: Urodynamic outcomes after hysterectomy for benign conditions: a systematic review and metaanalysis. Obstet Gynecol Surv 2012; 67: 45. 27. Suskind AM, Kaufman SR, Dunn RL et al: Population-based trends in ambulatory surgery for urinary incontinence. Int Urogynecol J 2013; 24: 207. 28. Dmochowski RR, Blaivas JM, Gormley EA et al: Update of AUA guideline on the surgical management of female stress urinary incontinence. J Urol 2010; 183: 1906.