Combined Urethral Bulking Agent and Intravesical Botulinum Toxin as Therapies for the Management of Mixed Urinary Incontinence

INTRODUCTION: One-third of women with urinary incontinence experience mixed urinary incontinence (MUI) characterized by both stress (SUI) and urgency urinary incontinence (UUI). One approach for MUI treatment is a combined procedure of urethral bulking and intravesical botulinum toxin A (Botox). These procedures are ideal for patients who are poor surgical candidates, have failed prior behavioral or pharmacologic therapies, or desire a minimally invasive, office-based treatment. There is insufficient literature on the real-world efficacy and safety of performing these two treatments in a single, office-based procedure. OBJECTIVE: To describe the short-term efficacy and safety of combined urethral bulking and intravesical Botox injection as a single office-based procedure for the management of MUI. METHODS: This was a retrospective cohort study of patients with MUI at a single academic institution who were scheduled for combined urethral bulking using polyacrylamide hydrogel and intravesical Botox from January 2022 to September 2024 by 5 fellowship-trained urogynecologists. Botox was performed using a rigid cystoscope followed by urethral bulking using the manufacturer’s optimal technique. Chart review was performed to identify demographic characteristics, pre-procedure diagnostics, treatment outcomes, and adverse event data. RESULTS: Twenty-nine patients were scheduled for a combined procedure, with a mean ± SD age of 75 ± 12 years, body mass index of 31 ± 7 kg/m2, and Charleston comorbidity index of 5 ± 2 (Table 1). Seventy-two percent were White and 86% used public insurance. Most patients had received prior therapies, including midurethral sling (45%), medication (48%), intravesical Botox alone (21%), urethral bulking alone (17%), and sacral neuromodulation (10%). Combined bulking and Botox were administered to 86% (25/29) of patients. Reasons for receiving only one therapy included pain at the time of procedure (3/29) and lack of demonstrable SUI on retrofill testing or urodynamic studies (UDS) (1/29). Formal UDS were performed on 55% (16/29) of patients. Clinical diagnoses of UUI were based on patient-reported symptoms with 17% (5/29) demonstrating uninhibited detrusor contractions on UDS. SUI diagnosis was confirmed via retrofill cough stress testing (62%, 18/29) or urodynamic stress incontinence on UDS (31%, 9/25) in most cases. Five patients were lost to follow-up after the procedure (Figure 1). A majority (80%, 16/20) reported significant improvement in incontinence symptoms or ≥50% reduction in incontinence episodes within 1 month of treatment (Table 2). Fifteen percent (3/20) reported complete resolution of incontinence. Positive responses were temporary with 65% (13/20) of patients reporting worsening incontinence within 6 months of treatment. Nearly all cases with recurrence had return of both SUI (12/13) and UUI (13/13). Forty percent (8/20) of patients underwent an additional procedure within 6 months, including repeat Botox (5/20), repeat bulking (3/20), and midurethal sling (2/20). There were 0 cases of urinary retention requiring catheterization and 5 cases (25%) of UTI that occurred within 2 months of treatment. CONCLUSIONS: Combined urethral bulking and intravesical Botox can be tolerated in the office and temporarily improve MUI in a refractory MUI cohort without adding significant risk. Additional research is needed to identify key patient and disease characteristics associated with optimal treatment response (Tables 1 and 2).