Management of hydrocephalus in the patient with myelomeningocele: an argument against third ventriculostomy.

The majority of children with myelomeningocele will have associated hydrocephalus. The management of hydrocephalus can be one of the most trying problems in this patient population. Cerebrospinal fluid (CSF) diversion will be required in these children for the remainder of their lives. Blockage of the outlets of the fourth ventricle and communication of the fourth ventricle with the central canal provides a mechanism for compensation. The signs and symptoms of CSF diversion malfunction, either shunt or third ventriculostomy, can be quite subtle. The objective indications of these malfunctions are less available after third ventriculostomy than when using mechanical shunting. The ease with which the diagnosis of malfunction can be made becomes the major advantage of mechanical shunting over third ventriculostomy.