The effect of botulinum toxin A in children with non-neurogenic therapy-refractory dysfunctional voiding – A systematic review

Dysfunctional voiding (DV) is a habitual voiding disorder caused by involuntary contraction or non-relaxation of the external urethral sphincter (EUS) during voiding. This contraction causes high post-void residuals (PVR), urinary incontinence and urinary tract infections (UTIs). Various treatments for DV are available, but some children do not respond. Intersphincteric botulinum toxin-A (BTX-A) may be a possible treatment for therapy-refractory children with DV. The aim of this systematic review is to summarize the effects and safety of intersphincteric BTX-A as a treatment for therapy-refractory DV in children. A systematic search in Embase, MEDLINE, Cochrane, and Web of Science databases was performed. Studies reporting on the usage of intersphincteric BTX-A as a treatment for DV in children were included. Data on PVR, maximum flow rate (Qmax), repeat injections and complications were extracted. From a total of 277 articles, five cohort studies were identified, reporting on 78 children with DV of whom 53 were female (68 %) and 25 were male (32 %). Sample sizes ranged from ten to twenty patients. Mean or median age at the time of intervention ranged from 8 to 10.5 years. Meta-analysis could not be performed due to lack of data. The narrative synthesis approach was therefore used to summarize the results. All studies showed significant decrease in PVR after BTX-A injection. Three studies showed a 33–69 % improvement on incontinence after BTX-A injection. Less UTIs were reported after treatment. A temporary increase in incontinence, UTIs and transitory numbness to the gluteus muscle were reported as side-effects. BTX-A could be a safe and effective treatment option for therapy-refractory DV in children by reducing PVR, UTIs and incontinence. Hereby, the synergistic effect of BTX-A and urotherapy should be emphasized in future management. Furthermore, this study identified gaps in current knowledge that are of interest for future research.