Efficacy of electromotive drug administration in delivering botulinum toxin a in children with neuropathic detrusor overactivity-outcomes of a pilot study

Background Intravesical botulinum toxin A (BtA) injection is well established in managing paediatric neuropathic detrusor overactivity (NDO). Electromotive drug administration (EMDA) is a less invasive method, which can be performed in the clinic, using pulsed electrical current for drug delivery via a urethral catheter. Few small studies report good outcomes following BtA via EMDA (BtA/EMDA) into bladders of children with NDO. Objective The objective of this study is to assess the efficacy of BtA/EMDA in children with NDO, reduced bladder capacity and compliance. Methods Twelve children with NDO on baseline urodynamic study were prospectively included. Pre-BtA/EMDA and post-BtA/EMDA results compared the following four parameters: maximal cystometric capacity, bladder compliance, maximal detrusor pressure (pDetmax) during detrusor overactivity and pDetmax at capacity. The Wilcoxon matched-pairs signed-rank test using Graphpad Prism 8 was used for analysis. Secondary outcomes include adverse effects and symptomatic improvement. Results Fourteen episodes of BtA/EMDA were performed. Five patients received 3.3 IU/kg of Botox (R), and five received 10 IU/kg (maximum 300 IU). Four patients received 10 IU/kg of Dysport (R). Two patients in the Dysport (R)/EMDA group also received Botox (R)/EMDA more than six months previously. Thirteen of 14 post-EMDA results were completed and included in the paired analysis. No statistically significant improvements in any cystometric parameters were demonstrated. Eight patients subsequently had intravesical BtA injections with significant improvements in both cystometric parameters and symptoms. Two patients subsequently transitioned to adult services; one was commenced on mirabegron, and one has undergone ileocystoplasty with Mitro-fanoff appendicovesicostomy. Discussion Despite some evidence to support BtA/EMDA in children with NDO, the authors were unable to replicate previously published positive cystometric and symptomatic outcomes. In addition, BtA/EMDA performed poorly when compared with conventional intravesical BtA injections. This implies failure of EMDA to deliver BtA correctly to the target tissue. The large size of the BtA molecule or the abnormal bladder wall in NDO could account for the negative results. Thorough preparation and consultation was undertaken before this study with BtA/EMDA, and it is discouraging that the authors were unable to reproduce the positive results of other groups. Conclusions Although safe and acceptable to most patients, the authors cannot recommend the use of BtA/EMDA for NDO in children at present.