Urethral bulking agents regained popularity in the treatment of female stress urinary incontinence (SUI) owing to their minimally invasive nature and favorable safety profile in the era of mesh-related concerns. The aim of this study is to describe the initial treatment outcomes and patient satisfaction rates of Polyacrylamide hydrogel (PAHG) (Bulkamid®) injection for the treatment of female SUI in  our country

After internal ethical board approval, the data of all female patients who underwent transurethral PAHG injection in the primary or secondary setting between December 2019 and March 2023 due to SUI or stress-predominant mixed urinary incontinence (MUI) were retrospectively evaluated.  Age, duration of complaints, pelvic examination findings, frequency of micturition, postvoid residual urine volume and invasive urodynamic study results were recorded. In all patients, a total of 2 cc PAHG was injected at 4 different sites on bladder neck-urethral junction. The primary outcome was treatment success which was defined as no pad use, negative ICS uniform CST and declaration of no SUI on ICIQ-SF question 6. The secondary outcome was patient satisfaction which was assessed by patient-reported definition of post-injection continence status on a phone interview

A total of 22 female patients with a mean age of 61.8 ± 2.7 (41-84) years were included. One patient who underwent oncological pelvic surgery (endometrium cancer) and had adjuvant pelvic radiotherapy, brachytherapy and chemotherapy complicated by bladder perforation was excluded . Six patients had stress-predominant MUI, 15 had SUI. PAHG injection was the primary treatment in 17 patients while 4 had previous SUI surgeries.  The median duration of symptoms was 24 (6-100) months. The median urinary incontinence frequency was 3/day (2-8). ICS uniform CST was positive in all patients. Eight (38%) of 21 patients had increased urethral mobility. In 8 patients, abdominal leak point pressure (ALPP) was below 60 cmH2O, which was indicative of intrinsic sphincter deficiency (ISD) (Figure 1). The mean operative duration was 16.7 ± 1.2 (10-30) minutes. One patient developed transient urinary retention postoperatively. Otherwise, there were no recorded complications. 
At 1 week follow-up, ICS uniform CST was negative in all patients. At a median follow-up of 17 (1-38) months, overall treatment success rate was 85.7% (18/21). Success rates in primary vs secondary setting and pure SUI vs MUI were 88.2% vs 75% and 80% vs 100%, respectively. Overall patient satisfaction rate was 90% (18/20). Satisfaction rates in primary vs secondary setting and pure SUI vs MUI were 93.6% vs 75% and 85.7% vs 100%, respectively (Figure 2). All patients with ISD reached success and satisfaction criteria following PAHG injection. None of the patients defined post-injection continence status as ‘worsened’.

PAHG entered the market in our country by the end of 2019. This was the first and largest series of our country. Our overall treatment success rate, which was defined as no pad use, negative ICS uniform CST and declaration of no SUI on ICIQ-SF question 6, was 85.7%. Our subjective success rate was 90% as determined by post-injection continence status being defined as” cured” and feeling confident enough to recommend PAHG injection to a friend. This stands on the upper end of the success range (61-95%) that has been reported in relevant studies. [1,2]. This might be a result of the heterogeneity of the outcome assessment tools, such as visual analogue scale, Likert scale, ICIQ-SF, Patient Global Improvement Questionnaire, Incontinence Impact Questionnaire and patients’ definitions of their new conditions on a scale from worsened to improved. Only a few studies compared the outcomes of PAHG injection in patients with pure SUI vs stress-predominant MUI and reported better outcome in pure SUI [3]. In contrary, we detected higher objective and subjective cure rates in stress-predominant MUI. This might be a reflection of small sample size (13 pure SUI vs 8 MUI). Eight patients had ALPPs below 60 cmH2O on preoperative invasive UDS. Regardless of being in the primary or secondary setting or having pure SUI or stress-predominant MUI, treatment success was 100% in these women with ISD. Supporting this data with a larger sample size might better reveal ISD’s value in predicting the outcome of urethral bulking treatment

In a contemporary female  cohort, PAHG injection proved to be a safe and effective minimally invasive treatment option for pure stress and stress-predominant mixed UI in both primary and secondary settings

Lose, G., et al., An open multicenter study of polyacrylamide hydrogel (Bulkamid(R)) for female stress and mixed urinary incontinence. Int Urogynecol J, 2010. 21(12): p. 1471-7
Braga, A., et al., Urethral bulking agents for the treatment of recurrent stress urinary incontinence: A systematic review and meta-analysis. Maturitas, 2022.
Trutnovsky, G., et al., Quality of life after periurethral injection with polyacrylamide hydrogel for stress urinary incontinence. Int Urogynecol J, 2011