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).

Inclusion Criteria: * Women ≥ 21 years * For \> 3 months, bothersome SUI (response of somewhat, moderately, or quite a bit) without UUI or stress-predominant MUI. For those with equal bother of UUI and SUI, clinician determination that SUI is more severe/significant than UUI is required. * A positive cough stress test on standardized non-invasive testing or urodynamic SUI within the past 18 months. * Normal PVR \< 150 mL * Candidate for either study procedure as determined by treating surgeon * Available for up to 3 years. * Agrees to randomization. Exclusion Criteria: * Anterior/apical vaginal prolapse beyond the hymen (\>0 on POPQ) * Urge-predominant mixed UI despite stable therapy * Advanced UUI/OAB 3rd line therapy treatment within 1 year of enrollment. * Planned hysterectomy, urethral or anterior/apical surgeries s requiring general anesthesia at the time of SUI treatment, during the last 6 months, or planned within the next 12 months. * Malignancy or history of radiation of the pelvis * Pregnant, post-partum, breast feeding or plans for pregnancy within 1 year * Incomplete emptying (PVR \> 150mL) * Prior anti-incontinence procedure * Neurogenic bladder * Unwilling to continue current UUI treatment until completion of primary outcome at 12 months * Prior adverse reaction to synthetic mesh or urethral bulking material * Chronic bladder or pelvic pain conditions (e.g., Interstitial cystitis, painful bladder syndrome, fibromyalgia, chronic pelvic pain, etc.) * 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.