Are we underestimating urinary retention following intravesical onabotulinumtoxinA in women with overactive bladder and a history of prior pelvic surgery?

Aims: This study's purpose is to review the rates of urinary retention requiring intermittent catheterization (IC) post intravesical OnabotulinumtoxinA (BTN/A) injection for idiopathic overactive bladder from a single practicing specialist urological surgeon.

Methods: We performed a retrospective review of a single Australian urologist to identify the rate of intermittent catheterization in our clinical setting. Logistic regression was used to assess associations between requirement of IC and risk factors for urinary retention.

Results: Ninety-four patients were included after inclusion and exclusion criteria were applied and the average age was 69.7 years (SD 17.2) and all participants were female. Thirty-six percent (n = 34) of patients required IC. Of patients requiring IC, 32% had a prior urethral sling, 35% had prior vaginal prolapse surgery, and 29% had a preoperative urinary tract infection (UTI). There was strong evidence of univariate associations between IC and prior sling (odds ratio [OR]: 5.26, 95% confidence interval [CI]: 1.64-16.55, p = 0.005), preoperative UTI (OR: 4.25, 95% CI: 1.31-13.08, p = 0.016) and prior vaginal prolapse surgery (OR: 4.91, 95% CI: 1.64-14.72, p = 0.005). Evidence that prior sling patients were more likely to require IC remained strong in a multivariable model (OR: 7.35, 95% CI: 1.59-34.11, p = 0.011).

Conclusion: Prior urethral sling surgery, prior vaginal prolapse surgery, and positive preoperative UTI, despite treatment, were found to be associated with a higher rate of initiation of intermittent catheterization. The rate of IC initiation of 36% was higher than reported in prior clinical trials.