Endoscopic third ventriculostomy (ETV) is an option for hydrocephalus treatment in patients with Myelomeningocele mostly after a previous shunt dysfunction. Late failure of ETV is a rare event and it is traditionally associated with dramatic symptoms of intracranial hypertension. In patients with myelodysplasia and neurogenic bladder dysfunction urodynamic deterioration can be a signal of neurological worsening as a consequence of tethered cord or shunt problems.We describe here a rare case of a 12 years-old female patient with myelomeningocele and evidence of a failure 10 years after a previously successful ETV whose initial symptoms were worsening of urinary complaints. After 02 months, she was admitted to emergency with seizures and acute hydrocephalus and was shunted.Pediatric neurosurgeons must follow myelomeningocele patients with successful ETV for a long time and take care of subtle alterations of organic functions that have close relationship with central nervous system integrity. Multidisciplinary approach can facilitate this strategy and avoids tragic outcome.