Abstract
We report a case of triventricular hydrocephalus associated with Chiari malformation type I. Triventricular hydrocephalus is characterized by the dilatation of both the lateral and third ventricles without expansion of the fourth ventricle. For this case, cerebrospinal fluid (CSF) circulation was evaluated in order to predict the effect of endoscopic third ventriculostomy (ETV). The present case was a 60-year-old male who was admitted to our hospital for progressive gait disturbance. On admission, magnetic resonance imaging (MRI) showed triventicular hydrocephalus and Chiari malformation type I. No aqueductal stenosis or obstruction were observed ; however, ballooning of the third ventricle was not observed despite being dilated. Radioisotope (Rl) cisternography indicated delayed CSF absorption, although reflux into the ventricles was not seen. As the cause of hydrocephalus was primarily considered to be the obstruction of CSF outflow from the forth ventricle, ETV was performed. During the procedure, ventriculography revealed the obstruction of both foramen of Luschka, but did not reveal the obstruction of the foramen of Magendie. Therefore, we judged this case to have communicating hydrocephalus. Finally ventriculo-peritoneal shunt and ETV were performed because impaired CSF absorption was observed preoperatively and no ventricular obstruction was noted in the ventriculography findings. The ventriculo-peritoneal shunt reduced the ventricular size and improved the patient's gait and cognitive functioning. For cases of triventricular hydrocephalus associated with Chiari malformation type I, EVT should be considered important for the evaluation of CSF circulation.
