Urethral bulking agents (UBA) are injections of an agent into the submucosal tissues of the urethra to increase the coaptation of the urethral walls, increasing urethral resistance. Due to its efficacy and safety, UBA could be an alternative treatment to women with primary or recurrent stress urinary incontinence (SUI), especially with intrinsic sphincter deficiency (ISD) and/or fixed urethra, and to older women with comorbidities.

The main objective of the present study was to evaluate the results of UBA injection (Bulkamid®) in women with urodynamic SUI USUI) and sonographic fixed urethra at 1 year follow-up.

A prospective study was designed including women with USUI who ask for surgical treatment, in a cohort of women with sonographic fixed urethra (bladder neck descent <5 mm). Demographic variables (age, body mass index, parity and previous SUI surgeries) were collected. Urinary incontinence symptoms were evaluated subjectively by the International Consultation on Incontinence Questionnaire (ICIQ-UI-SF) validated questionnaire, and objectively, by a 24h-pad-test and   urodynamics tests, including measurement of the maximal urethral closure pressure (MUCP). A transperineal ultrasound was performed to all women to evaluate bladder neck descent at baseline. ICIQ-UI-SF were repeated at 3 months after UBA and at 1 year follow-up, including a postsurgical urodynamics and pad-test. Satisfaction after surgery was evaluated by the Patient Global Impression of Improvement (PGI-1) questionnaire.

Up to 44 women with fixed urethra who underwent a UBA injection (Bulkamid®) were included in the study, with a median age of 73.5 (62.3 – 78.8) and median body mass index 27.6 (25.1 – 32.3). Only 4.5% were nullipara and up to 88.6% had history of previous SUI surgery (11 patients underwent 2 SUI surgeries and 2 women, 3 previous SUI surgeries). Comparison of the baseline study variables versus 3 months and 1 year follow-up is showed in Table 1 (17 women have not yet completed 1 year follow-up). The prevalence of symptoms of SUI decreased significantly, with some worsening between 3- and 12-months follow-up. Leakage measured by the pad-test decreased and MUCP increased. More than 70% of women expressed to feel much better after UBA at 3 months, although the degree of satisfaction decreased when evaluated at 1 year follow-up. No adverse effects have been reported, even in patients with presurgical voiding dysfunction confirmed by urodynamics.

Complex patients with fixed urethra improve SUI symptoms after UBA, with a safe profile, taking into account the decrease of efficacy in some patients at 1 year follow-up.

For patients with a severe USUI and fixed urethra, UBA are an effective and safe treatment with an acceptable degree of patient’s satisfaction.

Zheng Y, Rovner E. Update on Urethral Bulking for Stress Urinary Incontinence in Women. Curr Urol Rep. 2022 Oct;23(10):203-209. doi: 10.1007/s11934-022-01099-5
Hoe V, Haller B, Yao HH, O'Connell HE. Urethral bulking agents for the treatment of stress urinary incontinence in women: A systematic review. Neurourol Urodyn. 2021 Aug;40(6):1349-1388. doi: 10.1002/nau.24696.