Intradetrusor Injections of Onabotulinum Toxin-A in Children With Urinary Incontinence due to Neurogenic Detrusor Overactivity Refractory to Antimuscarinic Treatment

Purpose: This was a prospective single-arm study to assess the efficacy and safety of intradetrusor injections of onabotulinum toxin-A in children with urinary incontinence associated with neurogenic detrusor overactivity due to myelomeningocele. All patients had failed the first-line treatment of a combination of oral antimuscarinics and intermittent catheterization.

Materials and methods: The study group consisted of 31 children with myelomeningocele with a mean age of 7.95 years (range, 5-3 years) who were followed up for a mean of 29 weeks. The amount of onabotulinum toxin A injected was 10 U/kg with a maximal dose of 300 U. There were 20 to 30 injection sites with rigid cystoscopic guidance under general anesthesia.

Results: Thirty of 31 patients reported dryness between intermittent catheterization intervals. The mean reduction in maximum detrusor pressure and the mean increase in maximum cystometric capacity from baseline were 53% and 51.5%, respectively, 6 weeks after injection. We found a 324% increase in mean bladder compliance and a 57% increase in mean intermittent catheterization volumes. The mean duration of efficacy was 28 weeks with a single injection and 36 weeks for repeated injections (minimum, 16 weeks; maximum, 52 weeks). The mean time interval between repeated onabotulinum toxin-A injections was 7 months (maximum, 13 months). Intradetrusor injections of onabotulinum toxin-A were well tolerated.

Conclusions: Onabotulinum toxin-A injections into the bladder wall provide a significant symptomatic and urodynamic improvement in children with neurogenic detrusor overactivity due to myelomeningocele who are on intermittent catheterization. The treatment seems to be safe and very well tolerated.