Role of urodynamics in stress urinary incontinence: A critical appraisal

INTRODUCTION Role of urodynamics prior to surgery of stress urinary incontinence (SUI) is under constant debate. Demonstration of the presence of detrusor overactivity is the only aspect that has been emphasized in the literature so far. We believe that there are number of other factors which may influence the evaluation and in turn the choice of surgical management and prediction of outcome of treatment. They are as follows: (1) Presence of voiding inefficiency, (2) asymptomatic detrusor overactivity, (3) and severity of SUI. These features may complicate the precise evaluation of patients of SUI. The main objective of this study is to analyze the dynamics of leakage and voiding using urodynamics. This study also aims at correlating these findings with clinical information. MATERIALS AND METHODS One hundred consecutive cases referred to our center for preoperative evaluation of SUI were recruited in the study prospectively. All patients were interrogated using International Consultation on Incontinence Questionnaire. All patients underwent complete urodynamic evaluation including uroflowmetry, filling cystometry, leak point pressure measurement, and pressure flow studies, according to Good Urodynamic Practice guidelines. Patients' symptoms were correlated with urodynamic findings, with special emphasis on the presence of detrusor overactivity, severity of SUI, voiding efficiency, and presence of bladder outlet obstruction. Clinical information and urodynamic findings were correlated using Chi-square test. RESULTS There is a statistically significant correlation between the presence of symptoms of urge urinary incontinence and urodynamic findings of detrusor overactivity at P < 0.05. There is a statistically significant correlation between the symptoms of urge incontinence (in addition to SUI) and urodynamic findings of intrinsic sphincter deficiency at P < 0.05. Fifteen of 51 patients who did not have associated storage symptoms were found to have some degree of detrusor overactivity on urodynamic evaluation. There was no statistically significant correlation between asymptomatic cases of urge incontinence and incidental finding of detrusor overactivity at P < 0.05. There is no statistically significant correlation between the urodynamic findings of symptoms of voiding dysfunction and urodynamic findings, suggestive of the same value at P < 0.05. CONCLUSIONS Urodynamic study in SUI has a potential of giving much more information than demonstration of Detrusor Overactivity alone. The predominant symptom of urge urinary incontinence can predictably diagnose detrusor overactivity in these cases. However, the incidence of asymptomatic detrusor overactivity remains as high as 15% and may have implication in postoperative results. This study clearly shows that there is a definite incidence of significant voiding dysfunction, which cannot be reliably evaluated without properly conducted pressure flow study. This factor may govern the choice of correct treatment which also predicts the outcome more reliably. Preoperative urodynamic study thus adds a dimension of precision to evaluation of the patients of SUI and may also influence technique and outcome measures in this group of patients.