Urethral Sphincter Injection of Botulinum Toxin A: A Review of Its Application and Outcomes.

The first reported application of Botulinum toxin-A (BTX-A) into the urethral sphincter predates the first documented use in the bladder. The aim of this review is to describe the clinical indications of BTX-A injection into the urethral sphincter and its clinical efficacy. This review of the literature includes the larger more significant published studies that have reported on this use of BTX-A. Case reports and articles not published in English were excluded. There have been many published clinical studies describing the use of BTX-A in the urethral sphincter, four of which are randomized placebo controlled trials. These studies tend to include patients either in urinary retention or with obstructed voiding, both in the neuropathic and non-neuropathic populations. Studies tend to demonstrate improvements in urodynamic parameters and quality of life after injection. There have been many small clinical studies in this area, however larger placebo-controlled trials are needed to evaluate this treatment at higher levels of evidence.