Hypothesis / aims of study
Complications following mid-urethral sling placement can include pelvic pain, dyspareunia, voiding symptoms, retention, extrusion and recurrent urinary tract infections. These can occur in approximately 3.7% of patients and may require sub-urethral sling removal (SSR). Following SSR, stress urinary incontinence (SUI) may occur in up to 59% of patients1. Macroplastique (MPQ) is a bulking agent used in the treatment of stress urinary incontinence (SUI) secondary to intrinsic sphincter deficiency (ISD). Although the outcomes of Macroplastique have been previously examined in patients with stress urinary incontinence secondary to intrinsic sphincter deficiency 2-3, the success rate following sub-urethral sling removal has never been reported in the literature. Our study sought to evaluate outcomes following urethral Macroplastique (MPQ) injection in women with stress urinary incontinence following sub-urethral sling removal.
Study design, materials and methods
Following Institutional Review Board (IRB) approval, charts of non-neurogenic women with stress urinary incontinence after sub-urethral sling removal who underwent subsequent MPQ injection were reviewed from a prospectively maintained database. Patients with a history of neurogenic bladder, indwelling suprapubic tube or a follow-up time of less than 6 months were excluded. Two female pelvic and reconstructive medicine experts performed the MPQ injections on an outpatient basis under light anesthesia. Transurethral injections were performed at 3 and 9 o’clock positions at the mid-urethral level. A total of 5 ml injected, with 2.5mL at each injection site. Baseline data included UDI-6 and VAS Quality of Life (QoL) Questionnaire scores. Patients were followed with repeat questionnaires and three-dimensional ultrasound (3D US) evaluating volume and configuration of MPQ. Success following MPQ was defined as a self-reported composite score of a UDI-6 question 3 score of 0-1 and no additional anti-incontinence therapy.
From 2011 - 2018, 70 women with mean age 62.7 years met study criteria. At a mean follow-up of 46.4 ± 1.5 months, the success rate after MPQ injection was 45.7% (32 of 70 pts). Of the 38 patients who failed initial injection, 27 patients underwent a repeat MPQ injection with a success rate of 59% (16 of 27 patients). The overall success rate for the entire cohort was 68.6% (48 of 70 pts). Of the 11 patients who failed a second MPQ injection, 9 had stable MPQ volume / configuration on three-dimensional ultrasound (mean volume 8.43ml ± 0.72ml). Two of these patients went on to have autologous pubovaginal sling placement (PVS) to treat residual ISD with 100% success. Of the patients who did not seek a second injection, 11 sought no further treatment while 3 underwent autologous PVS placement. Despite objective failure, the majority of patients reported subjective improvement (83%) and reduced pad usage (78%). On multivariate analysis: age, BMI, previous hysterectomy, HRT, type of sling removed and baseline UDS parameters (Qmax, Pdet at Qmax, PVR and VLPP) were not predictors of MPQ failure. Higher parity was a predictor of MPQ failure (HR: 1.980, p = 0.032).
Interpretation of results
The management of SUI after sub-urethral sling removal for complications can be challenging. Many patients are hesitant to undergo a repeat synthetic sling, or even an autologous fascial sling. Macroplastique (MPQ) is a bulking agent used in the treatment of stress urinary incontinence secondary to intrinsic sphincter deficiency and it has an important role to play in this situation as demonstrated in this series with significant efficacy and long-term follow-up.