Botulinun A toxin urethral sphincter injection for neurogenic or nonneurogenic voiding dysfunction.

Voiding dysfunction due to detrusor underactivity or urethral sphincter dysfunction is a treatment challenge for urologists. Recently, urologists have used botulinum toxin A (BoNT-A) injection into the urethral sphincter to treat voiding dysfunction. This treatment has been found to decrease urethral pressure and postvoid residual volume, and increase voiding efficiency in patients with neurogenic detrusor sphincter dyssynergia, nonneurogenic dysfunctional voiding, and detrusor underactivity. Although not all patients can achieve excellent therapeutic outcomes, patients with idiopathic detrusor underactivity might have recovery of detrusor contractility after urethral sphincter BoNT-A injection. However, urinary incontinence might be a adverse event after treatment. Repeat urethral injection is necessary to maintain therapeutic efficacy. Patients should be fully informed of the limited therapeutic efficacy and possible adverse events prior to treatment. This article reviews recent studies of urethral sphincter BoNT-A treatment for voiding dysfunction.