Efficacy of Intravesical Oxybutynin in Children With Neurogenic Bladder Dysfunction

Inclusion Criteria: * Person affiliated to or beneficiary of a social security plan * In failure of treatment with one or more anticholinergics defined by a response considered insufficient by the investigator after at least 4 weeks of optimal dose treatment, unable to take oral oxybutynin or intolerable adverse events * Having performed renal ultrasonography less than 2 months ago * Having performed cystomanometry less than 6 months ago including maximal bladder capacity and maximal bladder pressure (preferably not under oral oxybutynin treatment) * Age between 6 and 17 years old * Informed about study organization, having given consent to participate and each legal representative have signed the informed consent * Having undergone the medical examination adapted to research * Presenting overactive bladder due to spina bifida confirmed by urodynamic check-up of less than 6 months. Overactive bladder is defined according to International Children's Continence Society, (ICCS): "a urodynamic observation characterized by involuntary detrusor contractions during the filling phase which may be spontaneous or provoked" * Carrying out intermittent catheterization for at least 6 weeks and at least three times a day * Able and volunteer to perform intravesical catheterization and instillation (patient or parents). Exclusion Criteria: * Person displaying known allergy to one of the components of evaluated product (notably oxybutynin). * Person with congestive cardiac failure * Person with cardiac arrhythmia * Person with tachycardia * Person with uncontrolled hypertension * Person under one of the following treatments : Bisphosphonates; Cytochrome P450 Inhibitors (such as ketoconazole and Erythromycin); Cholinesterase inhibitors. * Person displaying a contraindication to evaluated product, in particular: Hypersensitivity to oxybutynin; Myasthenia; Angle-closure glaucoma; Functional or organic gastrointestinal obstruction including pyloric stenosis, paralytic ileus and intestinal atony; Serious gastro-intestinal disorders (e.g., severe ulcerative colitis and toxic megacolon); Patients who have undergone ileostomy, colostomy, severe hemorrhagic colectasis or rectocolitis; Subvesical obstruction (urethral stenosis, posterior urethra valve); Ongoing treatment with anticholinergic drugs for another indication that could not be stopped; Patient with polyuria of other origin (renal, heart, potomania); Concomitant oxygenotherapy. * Woman of childbearing age without highly effective contraception (Sexual abstinence OR combined contraception by oral, intravaginal or transdermal ovulation inhibition OR progestin-only contraception by oral, injectable or implantable ovulation inhibition OR Intrauterine device or hormonal IUD). * Pregnant, parturient or breastfeeding woman. * Person deprived of liberty for judicial or administrative decision. * Person under psychiatric care as referred in articles L. 3212-1 and L. 3213-1. * Intradetrusor injection of botulinum toxin less than 6 months before. * Person with hyperthyroidism * Person with coronary cardiac disease.