SISTEr: Stress Incontinence Surgical Treatment Efficacy Trial

Bottom line Positive

In women with stress-predominant incontinence and urethral hypermobility, autologous rectus fascial pubovaginal sling improved 24-month overall and stress-specific success over Burch colposuspension (47% versus 38%; 66% versus 49%), with more urinary tract infections and voiding dysfunction.

Both prespecified success composites favored sling; urinary infections and emptying problems were more frequent.

SISTEr was a nine-center, open-label randomized superiority trial in 655 women with stress-predominant urinary incontinence and urethral hypermobility that compared an autologous rectus fascial pubovaginal sling with Burch colposuspension. At 24 months, the sling improved both overall composite success (47% versus 38%; P = 0.01) and stress-specific success (66% versus 49%; P < 0.001).^[1]

Design and population

Nine-center randomized surgical superiority trial with 24-month time-to-event analysis. Women with pure or stress-predominant urinary incontinence, a positive stress test and urethral hypermobility; prior incontinence surgery was permitted.

Arms

Autologous rectus fascial pubovaginal sling versus Burch colposuspension

Report and follow-up

2007 · 24 months; 520/655 women had an assessed outcome or a prior documented failure

Endpoint	Results	Effect	Finding
24-month Kaplan–Meier overall composite success; absolute risk difference in percentage points (sling minus Burch)	47% vs 38%	difference 9; P 0.01	Met
24-month Kaplan–Meier stress-specific composite success; absolute risk difference in percentage points (sling minus Burch)	66% vs 49%	difference 17; P <0.001	Met

Harms: Any adverse event: 206/326 (63%) vs 156/329 (47%); Urinary tract infection: 157/326 (48%) vs 105/329 (32%); Voiding dysfunction after six weeks: 14% of 326 vs 2% of 329

NCT00064662 · Report DOI

Design

Women had a positive standardized stress test and pure or stress-predominant symptoms. Prior incontinence surgery was allowed. Randomization occurred in the operating room after induction of anesthesia, stratified by clinical center. Participating surgeons used standardized operative elements, including Burch suture type and placement, fascial sling dimensions, antibiotic prophylaxis and cystoscopic bladder assessment. Planned concomitant prolapse operations and hysterectomy were declared before randomization.^[1]

Overall success required no self-reported incontinence, pad gain <15 g, no leakage in a three-day diary, a negative cough and Valsalva stress test, and no retreatment, including behavioral or drug treatment. Stress-specific success retained the symptom, stress-test and retreatment criteria but omitted the pad and diary components. Both were prespecified primary outcomes; the reported percentages are Kaplan–Meier estimates of cumulative success, with the treatment groups compared by a site-adjusted log-rank test.^[1]

Results

At 24 months, 520/655 women had an assessed outcome or an earlier documented failure. The absolute difference in overall composite success was 9 percentage points in favor of sling (47% versus 38%; P = 0.01); for stress-specific success it was 17 points (66% versus 49%; P < 0.001). These time-to-event estimates are not fractions of all randomized patients.^[1]

In a secondary analysis of this cohort, preoperative urodynamic stress incontinence showed a nonsignificant association with overall success (odds ratio 2.26, 95% CI 0.99–5.17). Valsalva leak point pressure and detrusor overactivity did not predict either surgical success outcome in the women studied.^[2]

E-SISTEr enrolled 482/655 original participants for observational follow-up. Under its narrower composite of no diary leakage, no reported stress symptoms and no surgical stress-incontinence retreatment, five-year cumulative continence was 30.8% after sling (95% CI 24.7–36.9%) and 24.1% after Burch (95% CI 18.5–29.7%; log-rank P = 0.002). Among five-year satisfaction respondents, 148/179 sling participants (83%) and 126/172 Burch participants (73%) were satisfied (P = 0.04).^[3]

Surgery and treatment delivery

The Burch operation suspended anterior vaginal tissue at the bladder neck and proximal urethra with permanent sutures fixed to the iliopectineal ligament. For the sling, surgeons harvested rectus fascia, placed the strip under the proximal urethra through a vaginal incision and brought its permanent suture ends retropubically to the anterior abdominal wall for fixation. The study standardized key dimensions and suture details across its centers.^[1]

All 326 sling assignments and 328/329 Burch assignments received the assigned operation. Concomitant prolapse surgery was performed in 55% of sling and 48% of Burch patients. Mean operative time was 136 versus 138 minutes and mean estimated blood loss 229 versus 238 mL, respectively, including concomitant procedures when performed.^[1]

Adverse events

Any adverse event affected 206/326 sling patients (63%) and 156/329 Burch patients (47%), chiefly because urinary tract infection affected 157/326 (48%) versus 105/329 (32%). The trial accepted either culture confirmation or treatment based on clinical suspicion for cystitis. Serious events, defined as modified Dindo grade III–V, occurred in 42/326 (13%) and 32/329 (10%; P = 0.20). Incident cystotomy was reported twice after sling and ten times after Burch; ureteral injury occurred only in two Burch patients.^[1]

Protocol-defined voiding dysfunction—catheter use after six weeks or revision to improve emptying—occurred in 14% after sling and 2% after Burch. Nineteen sling recipients underwent 20 revision procedures for voiding symptoms or retention; no Burch recipient required one. Treated postoperative urge incontinence affected 87/326 (27%) and 65/329 (20%). The excess was mainly persistent urge incontinence (79/326 [24%] versus 59/329 [18%]); new treated cases occurred in 11/326 (3%) and 11/329 (3%).^[1]

During E-SISTEr follow-up, adverse events were reported in 22/243 sling participants (9%) and 23/239 Burch participants (10%).^[3]

Limitations

Patients and clinicians knew the assignment after surgery, and more than half the cohort had another operation. SISTEr enrolled women with urethral hypermobility and stress-predominant symptoms at tertiary centers; 520/655 had a known two-year outcome or earlier failure. Its stringent overall composite counted urgency leakage and any incontinence retreatment as failures.^[1]

E-SISTEr changed the composite definition and was an observational extension: participants who were incontinent at two years were more likely to enroll than those who were continent (85.5% versus 52.2%). Its five-year estimates therefore describe the extension cohort under its own endpoint.^[3]

In conversation

Same setting Ward–Hilton (2002)

Guidelines and approvals

• AUA/SUFU (Surgical Treatment of Female Stress Urinary Incontinence, 2017; amended 2023), statement 12. Counsel index patients considering surgery about efficacy and safety of their options, including autologous fascia pubovaginal sling and Burch colposuspension .^[4]
• AUA/SUFU (2017; amended 2023), statement 19. In patients having concomitant prolapse repair and SUI surgery, clinicians may perform a pubovaginal sling or Burch colposuspension, among other continence procedures .^[4]

Report history

SISTEr report history

Published	Report	Cutoff	Headline results	Citation
2007-05-21	Two-year randomized report · primary	—	24-month Kaplan–Meier overall composite success; absolute risk difference in percentage points (sling minus Burch): 47% vs 38%; difference 9; P 0.01 Met 24-month Kaplan–Meier stress-specific composite success; absolute risk difference in percentage points (sling minus Burch): 66% vs 49%; difference 17; P <0.001 Met	Albo ME, Richter HE, Brubaker L, et al. Burch colposuspension versus fascial sling to reduce urinary stress incontinence. *N Engl J Med.* 2007;356(21):2143-2155. doi:10.1056/NEJMoa070416 DOI
2008-03-04	Preoperative urodynamic predictors · secondary	—	Odds ratio for overall success with versus without urodynamic stress incontinence, pooled across operations: The trend did not reach statistical significance; Valsalva leak point pressure and detrusor overactivity did not predict success.; OR 2.26; CI 0.99–5.17	Nager CW, FitzGerald M, Kraus SR, et al. Urodynamic measures do not predict stress continence outcomes after surgery for stress urinary incontinence in selected women. *J Urol.* 2008;179(4):1470-1474. doi:10.1016/j.juro.2007.11.077 DOI
2012-02-15	E-SISTEr five-year observational follow-up · updated	—	Five-year Kaplan–Meier continence under the extension composite: 30.8% (95% CI 24.7–36.9%) vs 24.1% (95% CI 18.5–29.7%); P 0.002 Descriptive Patient-reported satisfaction at five years: 83% vs 73%; P 0.04 Descriptive	Brubaker L, Richter HE, Norton PA, et al. 5-year continence rates, satisfaction and adverse events of Burch urethropexy and fascial sling surgery for urinary incontinence. *J Urol.* 2012;187(4):1324-1330. doi:10.1016/j.juro.2011.11.087 DOI

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References

1. Albo ME, Richter HE, Brubaker L, et al. "Burch Colposuspension versus Fascial Sling to Reduce Urinary Stress Incontinence." N Engl J Med. 2007;356(21):2143–2155. doi:10.1056/NEJMoa070416

2. Nager CW, FitzGerald M, Kraus SR, et al. "Urodynamic Measures Do Not Predict Stress Continence Outcomes after Surgery for Stress Urinary Incontinence in Selected Women." J Urol. 2008;179(4):1470–1474. doi:10.1016/j.juro.2007.11.077

3. Brubaker L, Richter HE, Norton PA, et al. "5-Year Continence Rates, Satisfaction and Adverse Events of Burch Urethropexy and Fascial Sling Surgery for Urinary Incontinence." J Urol. 2012;187(4):1324–1330. doi:10.1016/j.juro.2011.11.087

4. American Urological Association and Society of Urodynamics, Female Pelvic Medicine & Urogenital Reconstruction. Surgical Treatment of Female Stress Urinary Incontinence. 2017; amended 2023. Statements 12 and 19.