Long-term outcome of intravesical oxybutynin in children with detrusor-sphincter dyssynergia: with special reference to age-dependent parameters

Abstract

Aims: Intravesical instillation of oxybutynin is an accepted and effective treatment in children with neuropathic bladder-sphincter dysfunction, when oral oxybutynin results in inadequate suppression of detrusor overactivity or intolerable side effects. However, as yet no data are available on long-term use and outcome.

Methods: A patient cohort with detrusor-sphincter dyssynergia that started oral oxybutynin between 1995 and 1997 was re-evaluated 15 ± 1 years after the switch from oral to intravesical (n = 10), with urodynamic investigations, renal ultrasounds, DMSA-scintigraphy, (51)Cr-EDTA-clearance, and validated questionnaires on incontinence and quality of life.

Results: At follow-up, cystometric bladder capacity (CBC) had increased to the 25-50% percentiles for age, from the 5% percentile; mean end-filling pressure, 24.5 ± 14.4 cm H2O, had returned to the safe zone; bladder compliance expressed as a fraction of normal compliance for age (Wahl units) showed a statistically significant increase. At follow-up, the prevalence of renal scars was 30% (95% CI: 6-65%). Kidney lengths correlated with scarring at DMSA-scintigraphy, (51)Cr-EDTA-clearance did not. In 2 years of oral oxybutynin we documented 10 pyelonephritic episodes, in 15 years of intravesical oxybutynin only three. Urinary continence was reported as satisfying, its impact on quality of life as acceptable.

Conclusion: Percentile charts for cystometric bladder capacity and individual kidney lengths, age-dependent parameters, were invaluable in estimating long-term outcome, and the same goes for bladder compliance in Wahl units. We can conclude that intravesical oxybutynin provided more than adequate suppression of detrusor activity, without side effects, over a period of 15 years.

Keywords: bladder compliance; clean intermittent catheterization; cystometric bladder capacity; detrusor-sphincter dyssynergia; end-filling pressure; intravesical oxybutynin; kidney length; kidney scarring; myelomeningocele; neuropathic bladder-sphincter dysfunction; oral oxybutynin; pyelonephritis; urinary incontinence; vesicoureteral reflux.