Trial of Transurethral Bulking Agent Injection Versus Single-Incision Sling for Stress Urinary Incontinence

This is a multicentered, double-blind, randomized controlled, surgical trial of 358 women with inadequate symptom relief of stress urinary incontinence (SUI) or stress predominant mixed urinary incontinence (MUI) after conservative care.

The Primary Aim is to determine the comparative effectiveness (as defined by "much" or "very much" better on PGI-I) of transurethral bulking agent (TBA) \[for 1 or 2 injections in 12 months\] vs. single-incision sling (SIS) 12 months after treatment intervention in women with predominant stress urinary incontinence (SUI).

The BASIS trial is a multicentered, double-blind, randomized controlled, surgical trial with two active interventions, 1) a transurethral bulking agent (TBA) or 2) a single-incision sling (SIS). Both interventions are FDA-approved treatment options for urinary incontinence and will be used in line with their approved use. Participants will be randomly assigned to one of the interventions. A total of 358 women will be randomized 1:1 to TBA or SIS.

All participants will have data including demographics, medical history, and quality of life assessments as they relate to urinary incontinence collected at baseline. After undergoing treatment (either transurethral bulking agent or single-incision sling), participants will be asked to return to the clinic at 2-4 weeks, 3 months, and 12 months with additional follow-ups at 6 months, 24 months, and 36 months done over the phone.

The primary outcome of the BASIS trial is subjective success measured by PGI-I for TBA vs. SIS at 12 months.

Secondary outcomes include assessments of 1) retreatment rates within 12 months; 2) validated, objective measures of condition improvement through 36 months; 3) objective success at 3 and 12 months as measured by standardized cough stress test; 4) functional outcomes (activity level, perceived recover, sexual function, etc.); 5) quality of life assessments; 6) operative procedure data and adverse events; 7) pain and functional activity, need for sedation and anesthesia, de novo or worsening symptoms; 8) medical resource use (additional medications, procedures, or therapies); and 9) healthy utility measures.

Eligibility Criteria:
Inclusion Criteria:

* Women ≥ 21 years
* Bothersome SUI (PFDI-20 Q:#17 of somewhat, moderately or quite a bit) or stress predominant MUI (PFDI-20 Q:#16 \< Q:#17)50 for \> 3 months with well-controlled UUI on stable medication treatment through baseline and follow-up.
* A positive cough stress test or urodynamic SUI within the past 18 months.
* Normal voiding function as demonstrated by PVR \< 150 mL
* Candidate for either study procedure as determined by treating surgeon (i.e., failed or unable to perform conservative management for SUI including pelvic floor strengthening and failed or declines pessary option for SUI)
* Available for up to 3 years.
* Agrees to randomization.

Exclusion Criteria:

* Anterior/apical vaginal prolapse beyond the hymen (\>0 on POPQ) - Advanced prolapse may require additional surgery or potentially increase the risk of postoperative urinary obstruction and confound the results of the study.
* Urge-predominant mixed UI by UDI-6 despite stable therapy - Urge predominant UI would not be expected to improve after TBA or SIS and may bias results of interventions designed specifically for stress urinary incontinence.
* Planned hysterectomy, urethral or anterior/apical surgeries - additional surgery beyond TBA or SIS has potential to confound the results. Additionally, these procedures generally require general anesthesia and indwelling catheterization immediately post operatively. The impact of urethral instrumentation after TBA is unknown and could impact the efficacy of the urethral coaptation.
* Malignancy or history of radiation of the pelvis - The risk of foreign material rejection and mesh complications may be higher in women with pelvic radiation and other treatment for pelvic malignancy may impact primary outcomes.
* Pregnant, breast feeding or plans for pregnancy within 1 year - subsequent vaginal delivery and hormonal changes of breast feeding prior to primary outcome could impact the efficacy of either treatment.
* Incomplete emptying (PVR \> 150mL) - SUI surgery may increase the risk of urinary retention.
* Prior anti-incontinence procedure - the aim of the study is to identify the role of TBA and SIS in primary, uncomplicated SUI or stress predominant MUI management.
* Neurogenic bladder - the aim of the study is to identify the role of TBA and SIS in primary, uncomplicated SUI or stress predominant MUI management.
* Prior adverse reaction to synthetic mesh or polyacrylamide - to minimize risk of post procedure complications.
* Chronic bladder or pelvic pain conditions (e.g., Interstitial cystitis, painful bladder syndrome, fibromyalgia, chronic pelvic pain, etc.) - given the known risks of postoperative pain with SIS and higher risks of pain in those with baseline chronic pain, we aim to minimize post operative complications.
* Active 3rd line treatment for OAB/UUI with botulinum toxin, sacral neuromodulation stimulation (SNS) or percutaneous tibial nerve stimulation (PTNS) within 12 months or plan for 3rd line or new OAB/UUI treatment within 1 year of SUI surgery. For those on stable medication OAB/UUI treatment, participants should be on stable treatment for 3 months with adequate symptom control prior to baseline measures and plan to remain on stable therapy without 3rd line treatment plans within 1 year of SUI surgery. Those who have received 3rd line treatment (Botox. PTNS or SNS) should have a washout of 1yr from and no plans for restarting within the primary outcome timeframe of 1 year post procedure. Those using SNS for bowel leakage only and no UUI symptoms do not require minimum 3 months. Participants with MUI on OAB/UUI medication therapy will still need to have SUI worse than UUI at baseline. Randomization will be stratified based on presence of UUI treatment component.
* Active treatment for SUI with a pessary. For those using a pessary or other SUI support device, a 3-week washout period should occur prior to assessing baseline measures.