Long-term intravesical oxybutynin for neurogenic bladder in children has good urodynamic and renal outcome.

Background: Intravesical oxybutynin as treatment for neurogenic bladder in children is promising, especially for patients in whom oral oxybutynin fails due to systemic anticholinergic side effects. However, little is known about the long-term outcomes of intravesical oxybutynin in children.

Objective: To assess, in a single-centre retrospective observational cohort study, the long-term urodynamic and renal outcomes of intravesical oxybutynin treatment for neurogenic bladder in children due to congenital spinal anomalies.

Methods: 122 children who started intravesical oxybutynin before the age of 18 were included. The retrospective analysis focused on their urodynamics, X-ray cystography, DMSA (99 Tm-dimercaptosuccinic acid) scintigraphy, 51Cr-EDTA (51Cr-ethylene-diamine-tetra-acetic-acid) clearance, and need for augmentation cystoplasty. Urodynamic parameters during follow-up with intravesical oxybutynin were compared to baseline urodynamics prior to starting intravesical treatment, either without any anticholinergic medication or while on oral oxybutynin.

Results: Mean intravesical oxybutynin treatment duration was 7.8 years (SD 5.9). Compared to baseline urodynamics without anticholinergic medication (n = 53), the proportion of patients with normal range of age-adjusted bladder capacity increased significantly from 36 % to 81 % (n = 47; p < 0.001). Mean end-filling pressure decreased significantly from 49.6 cmH2O (SD 37.4) to 26.1 cmH2O (SD 20.4; n = 27; p = 0.017). Detrusor overactivity presence (>30 cmH2O) reduced significantly from 50 % to 18 % (n = 34; p = 0.007). Vesicoureteral reflux (VUR) presence dropped significantly from 45 % to 18 % (n = 99; p < 0.001). Compared to baseline urodynamics under oral oxybutynin (n = 62), a significant decrease in median end-filling pressure was the only notable difference found (Md = 24.5 cmH2O; n = 36). During follow-up with intravesical oxybutynin, 21 % (n = 26 out of 122) reported pyelonephritic episodes. At long-term, 29 % (n = 22 out of 77) had asymmetric kidney function distribution with renal scarring and 16 % (n = 20 out of 122) underwent augmentation cystoplasty. 97 % (n = 86 out of 89) maintained a GFR above 60 ml/1.73 m2/min. Longer treatment duration was a significant predictor for better age-adjusted bladder capacity, less detrusor overactivity and less VUR.

Conclusions: These long-term urodynamic and renal outcome data in a large study population demonstrate the efficacy of intravesical oxybutynin in paediatric patients with neurogenic bladder. The positive impact of intravesical oxybutynin on VUR is of clinical relevance since it is associated with upper urinary tract deterioration, eventually leading to renal function impairment. The association of longer intravesical treatment duration with improved urodynamic outcomes highlights the importance of continuous patient compliance in achieving favourable results. Conclusions: Intravesical oxybutynin treatment is effective for managing neurogenic bladder in children, with good long-term urodynamic and renal outcomes.