Predictors of Voiding Dysfunction after Mid-urethral Sling Surgery for Stress Urinary Incontinence

PURPOSE: Postoperative voiding dysfunction is a bothersome complication after mid-urethral sling surgery. The current study presents multiple repeated postoperative voiding trials against a urine load of preoperative functional bladder capacity, as estimated by a preoperative frequency volume chart, to identify the relevance of preoperative and immediate factors to the outcome. METHODS: A total of 180 patients were enrolled from August 2008 to August 2011. Patients received mid-urethral sling surgery with a transobturator tape, with or without concomitant cystocele repair. Patients reported relevant medical histories and a 3-day frequency volume chart and underwent urodynamic studies. After surgery, patients were filled to their maximum bladder capacity as dictated by their frequency volume chart and performed the first voiding trial. Two subsequent voiding trials were performed after natural filling. Failure of any single voiding trial was considered failure. Patients who failed the final voiding trial received intermittent catheterization to follow-up. After screening for relevant factors with the use of univariate analyses, preoperative, surgical, and postoperative factors predicting outcome were estimated by logistic regression analysis. RESULTS: The urine load at the voiding trial and the peak flow rate immediately preceding the voiding trial predicted voiding trial success in the multivariate analysis. Urine load and previous trial peak flow rate were relevant when tested against each individual voiding trial. Preoperative and surgical factors, such as age, parity, and concomitant cystocele repair, showed significance in the univariate analysis. Overall, 16.1% of patients who passed the first voiding trial failed on subsequent trials, whereas 36.8% of patients who failed the first voiding trial succeeded. CONCLUSIONS: Postoperative voiding dysfunction is transient and is associated with the immediate voiding conditions following surgery. Close observation against urine overload in the bladder is important when weaning patients back to normal voiding conditions.