Influence of preoperative detrusor underactivity on the continence rate and satisfaction after midurethral sling patient with stress urinary incontinence

Objectives: We studied the influence of preoperative detrusor underactivity in patients with stress urinary incontinence on the postoperative continence rates and patient satisfaction. Methods: Medical records of 41 female patients who had detrusor underactivity and had undergone a midurethral sling procedure with a follow up of at least 12 months were reviewed. The preoperative evaluation included a history taking, physical examination, voiding diary for 3 days and an urodynamic study. Detrusor underactivity was defined at pressure flow study by a maximal flow rate (Q_max) less than 15 mL/sec and a detrusor pressure at maximal flow rate (P_detQ_max) less than 20 cmH₂O. The postoperative evaluation included a continence state, questionnaire regarding patient satisfaction (5: very satisfied, 1: very unsatisfied), uroflowmetry and residual urine volume. Results: The mean patient age was 52.9 (range 39-68) years. Preoperatively, mean Q_max was 12.6 ± 2.1 mL/sec, mean residual urine volume was 16.1 ± 32.3 mL and mean P_detQ_max was 13.1 ± 4.7 cmH₂O. Postoperative continence rate was 88% (36/41). Five patients experienced minimal incontinence when they coughed violently. The amount of patients satisfied with postoperative status was 71%. Postoperatively, three patients needed medication with alpha blocker because of voiding difficulty. There was significant differences between preoperative and postoperative Q_max (13.1 ± 0.9 mL/sec vs 17.1 ± 0.9 mL/sec, P < 0.05). In addition postoperative residual urine volume (26.1 ± 27.9 mL) was significantly increased compared to the preoperative residual urine volume (16.1 ± 32.3 mL) (P < 0.05). Conclusion: Midurethral sling can be done safely for the patients with stress urinary incontinence and detrusor underactivity. However, the evaluation of preoperative detrusor function is important since the therapeutic outcome and postoperative voiding pattern may be affected by detrusor underactivity.