Botulinum injection is useless on fibrotic neuropathic bladders

Abstract

Objective Studies on the use of intradetrusor botulinum toxin A injection for children with neuropathic bladders are insufficient and the results are controversial. The aim of the present study was to evaluate the effect of intradetrusor botulinum toxin A injection for children with neuropathic bladders that are resistant to anticholinergic treatment, and to reveal any criteria indicating treatment success. Patients/methods Hospital records were reviewed of 16 children with neuropathic bladders due to myelomeningocele, and who had botulinum toxin A injections between 2007 and 2010. Botulinum toxin A (10 units/kg) was injected endoscopically into various sites of the detrusor, except the trigone. The success was defined as complete dryness between clean intermittent catheterizations. Urodynamic studies before and after the application were evaluated and parameters, including bladder capacity (measured/ expected) and compliance, were also analyzed. Reviewing the results, patients were then classified into two groups: as having fibrotic bladders (noncompliant, acontractile bladders with high pressures) or overactive bladders. Urodynamic findings and therapy success were then compared between the groups. Results A total of 19 injections, including repeat injections in three patients, were performed. Results of the 16 initial injections were evaluated. Nine patients had detrusor overactivity, and five out of nine (56%) applications in this group resulted in complete dryness between clean intermittent catheterizations. In bladders with typical detrusor overactivity, there was a significant increase in both the capacity (from 0.53 to 0.74) and compliance (from 4.7 to 8.6 ml/cm H2O). Looking at the seven patients that displayed fibrotic bladders with very low compliance and no contraction at all, none of them presented with notable clinical improvement from injections. Comparing the urodynamic findings, there was no significant difference in compliance (3.1 ml/cm H2O before and 3.5 ml/cm H2O after) and bladder capacity (0.58 before and 0.52 after the treatment) in the fibrotic bladders. Discussion Despite its worldwide usage and FDA approval, studies on the effectiveness of botulinumtoxin A on neuropathic bladders in children are controversial. There are now numerous studies attesting to the good results of BoNTA in neuropathic detrusor overactivity; however, only scarce reports comment on the specific features of the disease process among patients and reasons for failure in some. In our study, reviewing the urodynamic findings carefully, it was observed that the patients who did not respond to injections were the ones with no contractions, despite high pressures and low compliance. Therefore, describing the indications of BoNTA as neuropathic detrusor overactivity and urinary incontinence despite anticholinergic medications may lead to mistreatment of patients in the decompensated phase of a hyper-reflexive detrusor. Pretreatment urodynamic evaluation might be a good indicator, without biopsies, of estimating the degree of fibrosis and the patients who will benefit from the injection. Conclusion Botulinum toxin A injection in the neuropathic bladder of myelomeningocele patients was found to be ineffective if the detrusor was fibrotic, of low compliance and had lost contractility. Urodynamic findings should be carefully analyzed in order to select appropriate patients that may benefit from Botulinum injection.