Effect of Preoperative Flow Rate on Postoperative Retention and Voiding Difficulty After Transobturator Tape Operation

PURPOSE Controversy exists over the preoperative risk factors for postoperative urinary retention after the midurethral sling procedure for stress urinary incontinence (SUI). We intended to analyze the effect of preoperative flow rate on postoperative urinary retention after the transobturator tape (TOT) operation. MATERIALS AND METHODS A total of 322 patients who underwent TOT from June 2006 to May 2012 were included in this retrospective study. All patients were preoperatively investigated for urinary symptoms and underwent preoperative urodynamic studies including urine flow rate. Postoperative urinary retention, voiding difficulty, and uroflowmetry were checked. Urinary retention was defined as the need for additional catheterization longer than 1 day. Patients were divided by preoperative peak flow rate (Qmax) of 15 mL/s (low Qmax group and normal Qmax group). RESULTS There were 3 cases of postoperative urinary retention (0.9%) and 52 cases of voiding difficulty (16.1%). The low Qmax group included 40 patients (12.4%) and the normal Qmax group included 282 patients (87.5%). Between the two groups, there were no significant differences in age, previous pelvic surgery history, or past medical history. The low Qmax group had higher scores for voided volume and detrusor pressure at Qmax. However, there was no significant difference in postoperative voiding difficulty between the two groups. Furthermore, three patients who experienced postoperative retention showed high flow rates preoperatively. CONCLUSIONS Our results suggest that voiding difficulty in the group with low preoperative flow was tolerable and the treatment success rate was comparable to that in patients in the normal flow group. According to our analysis, patients with a low flow rate preoperatively can be safely treated with TOT for SUI.