Interna tional Neurourology Journal 2010;14:26-33 Predictors of Postoperative Voiding Dysfunction following Transobsturator Sling Procedures in Patients with Stress Urinary Incontinence Sung-Tae Cho, Hyeong-Cheol Song, Ha-Jong Song, Young-Goo Lee and Ki-Kyung Kim Department of Urology, Hallym University Kangnam Sacred Heart Hospital, Seoul, Korea This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

INTRODUCTION We evaluated the influence of preoperative physical examination (PE) and urodynamic study (UDS) findings on objective postoperative bladder emptying, the subjective development of bladder storage symptoms, and patient-reported success of correction of stress urinary incontinence (SUI). MATERIALS AND METHODS From January 2007 to August 2008, a total of 159 female patients with SUI underwent transobturator midurethral sling surgery (TOT). The patients were selected for SUI, with no overactive bladder (OAB) symptoms, no detrusor overactivity (DO) on UDS, no pelvic organ prolapse, and no history of prior anti-incontinence surgery. Of these patients, 128 patients (aged years; mean age, 51.8±7.1 years) with follow-up of at least 12 months were included in the analysis. All patients had PE and UDS findings, including Q-tip testing, free maximal flow rates (Qmax), filling cystometry, Valsalva leak point pressure, detrusor pressure at maximal flow, and maximal urethral closing pressure. The primary outcome was postoperative voiding dysfunction, defined as the subjective feeling of not empting one’s bladder completely and a postvoid residual ≥100 ml. A secondary outcome, "cure" of SUI, was defined as "a negative result on the cough stress test and no subjective complaint of urine leakage." We analyzed the preoperative parameters by univariate and multivariate regression for voiding dysfunction, de novo OAB, cure rate, and the patients’ satisfaction. Interna tional Neurourology Journal 2010;14:26-33

RESULTS Patients with a preoperative Qmax < 15 ml/s (7 patients) had a tendency for postoperative voiding dysfunction compared with those with a Qmax 15 ml/s (15 patients) (35.0% vs. 13.9%, respectively; p=0.046). No other preoperative parameters had a statistically significant influence on postoperative voiding dysfunction. Receiver operating characteristic (ROC) analysis revealed that Qmax was a good predictor because the area under the ROC curve value of Qmax was 0.81 (95% CI: 0.73 to 0.89, p<0.001). The univariate and multivariate analysis of the preoperative PE and UDS parameters demonstrated that no significant differences and no independent risk factors were related to the postoperative de novo OAB, cure rate, or the patients’ satisfaction. CONCLUSIONS These findings suggest that preoperative UDS results, especially Qmax, could be used to predict postoperative voiding dysfunction after the TOT procedure. Interna tional Neurourology Journal 2010;14:26-33

Table 1. Characteristics of the patients Interna tional Neurourology Journal 2010;14:26-33

Figure 1. Results of comparing preoperative parameters including maximal free flow (Qmax), detrusor pressure at maximal flow (PdetQmax) in patient with postoperative voiding dysfunction (PVD). Interna tional Neurourology Journal 2010;14:26-33

Figure 2. Receiver operating character (ROC) curve analysis. The area under the ROC curve (AUC) value of Qmax was 0.81 (95% CI 0.73 to 0.89, p<0.001) and the AUC of PdetQmax was 0.52 (95% CI 0.39 to 0.65,p=0.76), respectively.

Interna tional Neurourology Journal 2010;14:26-33 Table 2. Multivariate analysis for predictive factor for postoperative voiding dysfunction and de novo OAB

Interna tional Neurourology Journal 2010;14:26-33 Table 3. Multivariate analysis for cure of USI and the patients’ satisfaction