Long Term Voiding Function Following Retropubic Sling.

Abstract

Introduction: Midurethral slings (MUS) are highly effective in the management of stress urinary incontinence (SUI). Voiding dysfunction is a well-recognized complication of any sling procedure even if MUS is placed tension-free. Retropubic slings carry an increased risk of early voiding dysfunction compared with transobturator or single incision slings but there is limited information on voiding function in the long-term. Objective(s): To assess long-term voiding dysfunction in women following insertion of retropubic midurethral sling Methods: We conducted a retrospective cohort study of women who had a retropubic MUS 5 years or more previously. The study population comprised both women who were contacted from chart review and offered participation in addition to women who attended with pelvic floor symptoms and had undergone a MUS. The primary outcome was the change in maximum flow rate (Qmax) and post void residual (PVR) at uroflow assessment with a minimum voided volume of 100ml from baseline to follow-up. Secondary outcomes were subjective outcomes based on validated quality of life questionnaires for voiding dysfunction: International Prostate Symptom Score questionnaire (IPSS). IPSS correlates well with degree of bother and effect on QOL when studying lower urinary tract symptoms (LUTS) in women. A total score of >20 indicates severe symptoms. IPSS-Voiding/Storage (V/S) ratio of <1.3 suggests storage rather than voiding dysfunction. Univariable and multivariable linear mixed-effects models were used to assess changes in logarithmically transformed measures of volume voided, Qmax and PVR, accounting for the within-subjects design (before and after surgery at long-term follow-up visit) and loss to follow-up. Result(s): One hundred and fourteen women agreed to participate in the study. The median time from surgery to follow-up was 76.5 (IQR 65.0, 96.0) months. A total of six (5%) women had sling loosening within two weeks of surgery. There was a significant reduction in the Qmax from the preoperative to follow-up: Qmax 27ml/s (IQR 21, 34.5) to 18ml/s (IQR 12, 28); p <0.001. The PVR increased from 15ml (IQR 5, 50) to 31.5ml (16, 60) from preoperative to follow-up; p = 0.003. These changes remained significant when adjusted for age at surgery, point Ba > 0 at follow-up, previous surgery for stress urinary incontinence and follow-up time (Qmax p<0.001, PVR p = 0.005). One clinical definition of voiding dysfunction includes Qmax <15 ml/sec and/or PVR >100ml. By this definition, preoperatively 14% (16/116) had a Qmax <15ml/sec, 3.5% (4/114) had PVR >100 ml and 1.7% (2/114) had both. At follow up 36% (41/114), 11% (13/114) and 7% (8/114) met the same criteria for Qmax, PVR and both respectively. The median IPSS score at follow-up was 10 (IQR 4,15). A total of 82% (84/102) had an IPSS score <= 20. The median IPSS V/S at follow-up was 0.8 (0.3, 1.2); 82% (83/101) had a score <1.3. At follow-up, 15% (17/112) had a positive cough stress test. Conclusion(s): Retropubic midurethral sling was associated with a decrease in Qmax and an increase in PVR but no clinical intervention was required in this cohort at a median follow up of 6 years.