The Role of Chemical Sphincterotomy with Urethral Botulinum Toxin Injection in Patients with Neurogenic and Non-neurogenic Failure to Empty

Abstract

This review focuses on the evidence for injection of botulinum A toxin (BTX) to the external urinary sphincter for management of impaired bladder emptying secondary to neurogenic conditions such as detrusor sphincter dyssynergia (DSD) and non-neurogenic conditions such as dysfunctional voiding (DV). The application of urethral BTX for patients with impaired emptying secondary to detrusor underactivity will also be discussed. The goal of the review is to comprehensively analyze the evidence surrounding urethral BTX in this context and help guide decision-making. A robust body of literature including case series, a randomized control trial (RCT), and a meta-analysis support the use of urethral BTX for the treatment of DSD in spinal cord injury (SCI) patients, with documented improvement in urethral pressure and post-void residual urine volume (PVR). A second RCT among patients with DSD and MS demonstrated no improvement in urethral pressure, PVR, or maximum urine flow rate following urethral BTX relative to control. For non-neurogenic conditions like DV and pelvic floor spasticity, there are mixed data regarding the efficacy of urethral BTX. Small series have reported improvement in PVR and urethral pressure, but a RCT in this patient population demonstrated no benefit of urethral BTX relative to control. Urethral BTX effectively lowers urethral pressure and PVR in SCI patients with DSD, though the long-term impact on renal function requires further study. For patients with MS and those with non-neurogenic conditions like DV, pelvic floor spasticity, and detrusor under activity, the role of urethral BTX is not well defined. Further study in these patient populations should be undertaken prior to widespread utilization.