Effect of intrinsic sphincter deficiency on treatment success following urethral bulking with polyacrylamide hydrogel

Intrinsic sphincter deficiency (ISD) is associated with lower stress urinary incontinence (SUI) treatment success. Polyacrylamide hydrogel (PH) is a widely used urethral bulking material in treating SUI. Our goal is to compare treatment outcomes in women with and without ISD who underwent urethral bulking with PH for SUI.

We conducted a retrospective cohort analysis of women who underwent urethral bulking with PH from October 2022 to November 2024. Exclusions included no SUI on preoperative urodynamics, prior surgical SUI treatment, or no follow-up visit. ISD was defined as cough or Valsalva leak point pressure ≤60 cm H₂O or maximal urethral closure pressure ≤20 cm H₂O on preoperative urodynamics. Treatment success was defined as no SUI or improved SUI at initial follow-up.

Of the 171 participants included, 21 (12.3%) met criteria for ISD. Those with ISD were older and received a greater amount of PH compared to those without ISD (1.79 mL vs. 1.65 mL, p=0.05). There were no differences in self-reported race/ethnicity, body mass index, parity, or rates of concomitant prolapse repair. There were no differences in uroflow or micturition pattern or bladder sensation on preoperative urodynamics. Treatment success was high in both (95.2% with ISD vs. 89.9% without ISD, p=0.70). Rates of SUI retreatment were low in both and did not differ.

While there were some differences between those with and without ISD, both had high treatment success rates. Using PH bulking injection to treat SUI in those with ISD is reasonable.