Factors predicting the success of intradetrusor onabotulinum toxin-A treatment in children with neurogenic bladders due to myelomeningocele: The outcomes of a large cohort

Objective: This study aimed to determine the effectiveness of intradetrusor injections of onabotulinum toxin-A (BoNT-A) in pediatric patients with neurogenic bladders (NB) due to myelomeningocele (MMC). The factors predicting success were also evaluated.

Study design: We retrospectively identified 62 patients with NB due to MMC who underwent intravesical BoNT-A injection (100-300 U) between May 2013 and December 2018. Indications for BoNT-A injection were according to the European Association of Urology guidelines and included children for whom clean intermittent catheterization (CIC) and anticholinergic therapy had failed. Children who had previous bladder surgery or anti-reflux operations, coagulation disorders, myasthenia gravis, and non-neurogenic bladders were excluded. Twenty-one patients had accompanying vesicoureteral reflux (VUR). Preoperative and postoperative urodynamic parameters, clinical success, and VUR grades for all patients were recorded. Clinical success was defined as 4 h of dryness or bladder control between CICs. Logistic regression analysis was performed to evaluate the factors affecting treatment success.

Results: The mean age of the children was 9 ± 3.36 years. The mean follow-up was 28.5 ± 12.2 months. Clinical success was achieved in 64.5% (n: 40) of the patients. The mean maximal cystometric capacity increased from 172.4 ± 45.6 mL to 236.3 ± 67.2 mL. The mean bladder compliance increased from 14.8 ± 8.1 mL/cm H₂O to 19.3 ± 7.4 mL/cm H₂O, and the mean maximal detrusor pressure decreased from 56.7 ± 18.8 cm H₂O to 36.6 ± 10.1 cm H₂O. Urodynamic parameters did not improve in patients with hypocompliant (fibrotic) bladders. In patients with accompanying VUR, reflux was completely resolved in 53.8% (n: 14) of the ureters, improved in 26.9% (n: 7) of the ureters, and remained unchanged in 19.2% (n: 5) of the ureters after subureteral injection.

Conclusion: Intradetrusor BoNT-A injections provide excellent outcomes in children with NB refractory to conservative treatments. Poor responses were observed in patients who had low-compliant bladders without detrusor overactivity.