Risk Factors Associated with Postoperative Urinary Retention Following Mid-Urethral Sling

Objectives: Mid-urethral sling (MUS) is the most commonly used surgical procedure to correct stress urinary incontinence in women, and a well-known risk of this surgery is postoperative urinary retention. This study aims to investigate risk factors and possible ways to mitigate this complication. A previous randomized-controlled trial demonstrated that tamsulosin was effective at reducing postoperative retention through its alpha antagonist mechanism of relaxing the bladder outlet following surgery for pelvic organ prolapse, but patients undergoing MUS were excluded from this study. Determining if tamsulosin is beneficial in preventing urinary retention after MUS could be a significant step in improving outcomes with this procedure.

Methods: This retrospective study was conducted using the electronic medical record to obtain a cohort of patients who underwent retropubic MUS procedures between January 2020 and December 2022. Patients were excluded if they underwent a concurrent procedure, had a cystotomy requiring prolonged catheterization or underwent a transobturator or fascial sling. Variables including demographic characteristics, preoperative diagnoses, preoperative medications and intraoperative data were collected. Postoperative urinary retention was defined as failing a postoperative active voiding trial and being discharged home with a catheter. Power calculations were completed based on an average rate of urinary retention of 30% with the suspected rate of urinary retention decreasing to 10% in previously published studies. This calculation estimated a sample size of 124 patients. Patient characteristics were analyzed using chi-square and t-test, as appropriate. Univariate and multivariate analyses were completed for all variables.

Results: 434 patients were identified on the initial chart review. After screening patients based on the exclusion criteria, a cohort of 189 patients who underwent only a retropubic MUS and cystoscopy remained (Table 1). Seventy patients (37.1%) had received perioperative tamsulosin, while 119 patients did not. Twenty patients (10.5%) were discharged home with a catheter due to postoperative urinary retention. Those with urinary retention were older (62.2 vs 55.8, p=0.025) and had a lower BMI (26.9 vs 32.6, p=0.002). Multivariate logistic regression demonstrated that increasing age was associated with increased rate of postoperative urinary retention (OR 1.04) while increasing BMI was associated with a decreased rate of urinary retention (OR 0.86). Tamsulosin was not significantly associated with postoperative urinary retention. (Table 2)

Conclusions: This retrospective study demonstrates that BMI and patient age were associated with postoperative urinary retention following MUS procedure, while tamsulosin was not.