Relationship between Proximal Urethrovaginal Space Thickness and Detrusor Overactivity in Women with Stress Urinary Incontinence

PURPOSE: Detrusor overactivity (DO) cannot be predicted by clinical symptoms. Although it is possible that DO could be related to anatomical structures, scanty data exist about the relations between DO and anatomical structures. The aim of this study was to investigate anatomical differences in DO by measuring the thickness of the urethrovaginal space (UVS) and the urethral length (UL) in women with stress urinary incontinence (SUI). MATERIALS AND METHODS: Prospective data were collected from 72 women with SUI who underwent the midurethral sling operation. The subjects were divided into 2 groups according to the presence of DO by preoperative urodynamic study (UDS). UVS thickness was measured by trans-vaginal ultrasound. UL was measured by using a urethral catheter and a ruler. UVS thickness, UL, Q-tip, and urodynamic parameters, such as maximal urethral closure pressure (MUCP) and Valsalva leak point pressure, were compared between the two groups. RESULTS: Of 72 women, 23 patients had DO (31.9%). The proximal UVS was significantly thinner (p<0.001) and the MUCP was significantly lower (p=0.008) in women with DO. According to the receiver operating characteristic (ROC) curve based DO prediction, the best cutoff value for UVS thickness was 0.84 cm (area under the ROC curve 0.763). CONCLUSIONS: In this study, the proximal UVS was significantly thinner and the MUCP was significantly lower in patients with DO. A proximal UVS thickness of less than 0.84 cm was shown to be a predictive parameter for the development of DO on preoperative UDS. A large-scale prospective study is needed to validate these results.