Repeated detrusor injection of botulinum toxin A for neurogenic bladder in children: A long term option?

[AIMS] Evaluation of repeated (at least 4) intra-detrusor injections of toxin botulinum A (IDI-TBA) for neurogenic bladder in a pediatric cohort.

[METHODS] Patients who underwent at least 4 IDI-TBA between 2005 and 2017 for neurogenic bladder related issues were included (detrusor overactivity and low compliance). Clinical and cystometric data were collected before and after the first injection and after the last injection. The primary endpoint was the proportion of patients with non-abnormal cystometry (no detrusor overactivity and normal compliance). Secondary outcomes were the evolution of the observed bladder capacity/expected ratio, surgical complications and acquired kidney impairment.

[RESULTS] From the 832 patients referred to our institution for neurogenic bladder, 48 underwent IDI-TBA, and 17 at least 4 injections. Among them, a total of 95 procedures were performed (median per patient 5 [4-8]). While the first injection had a significant effect for 82.3% patients, the last injection improved the medical condition for only 53.0% cases. The bladder capacity ratio, initially 36.1%, increased to 80.3% after the first injection but decreased to a level of 57.1% at last. After a median follow-up of 57 [34-102] months, no severe complications were reported but 11.8% of patients presented with repeated pyelonephritis. A bladder augmentation surgery was finally indicated for 35.3% cases.

[CONCLUSIONS] Despite a low complication rate and impressive cystometric results after the first injection, IDI-TBA efficacy decreased with time and repetition. These findings prone a long-term follow-up and a "à-la-carte" management of this specific population depending on the long-term response to IDI-TBA.