The effect of midurethral slings on denovo urgency and urgency urinary incontinence.

Abstract

Hypothesis/aims of study Systematic reviews have suggested that the rate of denovo irritative voiding symptoms from RCTs of midurethral slings (MUS) is in the order of 11-19% (1). Population based prevalence studies have indicated a greater impact on health related quality of life from the urgency component of lower urinary tract symptoms (2). Although MUS procedures are generally very effective in treating stress urinary incontinence (SUI), there is a concern these procedures might lead to de novo urgency urinary incontinence, and consequently patient dissatisfaction. We aim to determine the independent risk factors for development of denovo urgency (dU) or denovo urgency urinary incontinence (dUUI) following MUS procedures. Study design, materials and methods We prospectively assessed 598 consecutive women who presented without urgency or urgency urinary incontinence, all of whom underwent MUS surgery from May 1999 till Aug 2007, with a mean follow up of 50 months. Consent was obtained from women together with approval from the local ethics committee. Comprehensive history comprised of demographics, medical history, symptoms of lower urinary tract and pelvic floor dysfunction, followed by full physical examination, urodynamic assessment and surgical reports, recorded on a detailed proforma. dU or dUUI was defined as occurring in those women who presented without urinary urgency OR urgency urinary incontinence and subsequently developed urinary urgency or urgency urinary incontinence following MUS, respectively at long term follow up. Women who defaulted from follow up were interviewed via telephone using structured questionnaires derived from Urogenital Distress Inventory (3). Clinical data were separated according to presence or absence of (i) dU (n=374); (ii) dUUI (n=598). Chi-square tests, independent t tests, and ANOVA tests were used to compare the two groups (presence vs. absence of dU or dUUI) by baseline characteristics and clinical factors. Clinical parameters possibly associated with each of above factors were assessed using multiple logistic regression analysis with stepwise building of an optimal model for prediction. Receiver operator curve (ROC) was performed for calculated probabilities from the final model. Results The mean age was 59.4+/-13.3 years. The overall subjective rate for dU & dUUI was 27.7% & 13.7% respectively. The mean follow-up was 215.3+/-101.9 weeks. Results of univariate analysis of clinical parameters is summarised in Table 1, with Table 2 summarising the independent risk factors for developing dU or dUUI. Age, length of follow up, menopausal status, use of HRT, parity, cystometric capacity, volume at first sensation, urodynamic voiding dysfunction level of surgical experience, type of anaesthesia, presence of intraoperative bladder perforation, use of mesh for prolapse surgery, were not significant risk factors (p>0.05). Multivariate analysis showed intrinsic sphincter deficiency (ISD), previous stress incontinence surgery, urodynamic detrusor overactivity (DO) confers significant odds whereas concomitant apical prolapse surgery confers inverse odds towards developing dU or dUUI post MUS. Interpretation of results The presence of intrinsic sphincter deficiency (ISD), history of previous sling / colposuspension or prolapse surgery and urodynamic detrusor overactivity (DO) significantly increased the risks of women developing dU or dUUI post MUS. A concurrent apical prolapse operation protects against developing dU or dUUI post MUS. The ROC for dU and dUUI indicate the model is a good fit with area under curve of 0.7875 and 0.6851 respectively. Concluding message Previous stress incontinence surgery, presence of urodynamic ISD or DO significantly increases, whereas concomitant apical prolapse surgery significantly decreases the risk of women developing denovo overactive bladder symptoms following MUS. (Figure Presented).