Durability of Macroplastique In Women With Stress Urinary Incontinence Secondary to Intrinsic Sphincter Deficiency

INTRODUCTION/OBJECTIVES: Macroplastique (MPQ) is a urethral bulking agent used in the treatment of stress urinary incontinence (SUI) in women with intrinsic sphincter deficiency (ISD). MPQ has been emerging as a viable bulking agent in the United States since 2011 when Collagen (Contigen) became no longer available. Prior studies with Collagen suggest that a stable volume and circumferential configuration of bulking agent around the urethra result in improved clinical outcomes. However, little is known about the durability of the volume/configuration of MPQ over time. Three-dimensional ultrasound (3DUS) is an ideal modality to image the irregularly shaped and echogenic MPQ. Our goal is to evaluate the durability of MPQ in women with SUI secondary to ISD using serial 3DUS measurements. We hypothesize that MPQ will maintain its volume/configuration around the urethra over time. METHODS: Following IRB approval, charts of non-neurogenic women with SUI and ISD (low VLPP; lateral imaging of urethral support with no hypermobility) who underwent MPQ were reviewed from a prospectively maintained database. All had at least two 3DUS measurements after their last MPQ injection. Excluded were women with prior bulking agent injection, urethral hypermobility, or follow-up <6 months. 3DUS was performed using the Philips IU22 ultrasound system with endovaginal 3D 9-3V end-fire probe (Philips Healthcare, Bothell, WA) at 6-8 weeks post-injection and yearly thereafter. The same senior sonographer blinded to clinical outcomes evaluated volume and configuration circumferential/symmetric or asymmetric) at each 3DUS. RESULTS OBTAINED: Between 2011 and 2016, 38 of 146 women met study criteria. Those excluded were due to prior other bulking agent injection (21%) or insufficient 3DUS follow-up (79%). The average age and BMI were 64 and 28, respectively. 63% of patients had prior anti-incontinence surgery. The mean time from first to last 3DUS was 19 months (range: 6-42 months). The mean time between first and second ultrasound was 13 months. An average of 5.6cc were injected total in each patient (range 2.5-10cc). 76% of patients had 1 injection, while the remainder had 2 or more (24%). The change in volume from first 3DUS measurement to last 3DUS measurement decreased from a mean of 5.8cc to 5.5cc (mean change = -0.3 (95% Cl: -0.5, -0.04); p = 0.0262). 29 patients had symmetric MPQ at first 3DUS, out of whom only 4 (14%) had a follow-up 3DUS showing asymmetric MPQ distribution. CONCLUSIONS: At mid-term follow-up, MPQ maintains both its volume and configuration in the urethral wall.