Spontaneous third ventriculostomy: definition by endoscopy and cerebrospinal fluid dynamics.

Chronic obstructive hydrocephalus is known to cause ventricular diverticula and, rarely, spontaneous ventriculostomy. The authors present the case of a patient in whom a spontaneous third ventriculostomy was identified with long-standing hydrocephalus secondary to aqueductal stenosis. To their knowledge, this is the first report in which a spontaneous stoma in the floor of the third ventricle was evaluated using endoscopy and cerebrospinal fluid dynamics studies. Both studies confirmed that the spontaneous stoma is similar in structure and function to surgical third ventriculostomy.