A Clinical Study to Investigate How Solifenacin Fluid is Taken up, How Long it Stays in the Body and How Effective and Safe it is in Treating Children Aged From 2 Years to Less Than 5 Years With Symptoms of Neurogenic Detrusor Overactivity (NDO)

In children with a severe form of spina bifida (which is the consequence of a spinal cord defect) it can happen that the bladder muscle (detrusor) contracts strongly and without warning (neurogenic detrusor overactivity) and that the urethra (the passage connecting the bladder with outside) does not relax. Those children cannot void but urine leakage can happen when the pressure in the bladder is so high that it overcomes the closed urethra (overflow at high filling bladder pressure) and/or when an overactive contraction is very strong. The high bladder pressure before overflow occurs puts those children at risk for kidney damage and the overactive contractions decrease the quality of the bladder additionally to the fact that they can cause leakage. Therapy is aimed to decrease the high filling bladder pressure and the overactive detrusor contractions. The purpose of this study is to evaluate long term efficacy and safety of treatment with solifenacin succinate (the study drug) and blood levels of solifenacin succinate (the study drug) in children with neurogenic detrusor overactivity after multiple dose administration.