Classification of hydrocephalus and outcome of treatment

Purpose: Retrospective analysis in cooperative study of hydrocephalus at institutions of members of the Research Committee on Intractable Hydrocephalus sponsored by the Ministry of Health and Welfare of Japan was performed to determine the functional prognosis for all types of hydrocephalus and thus to clarify the outcome. Methods: In preparation of this study, we have proposed the definition, clinical classification and diagnostic criteria of hydrocephalus. We have classified non-tumoral hydrocephalus into eight types based on its etiology and the time of onset. To establish the diagnosis in each type of hydrocephalus, we have set up inclusion and exclusion criteria, as well as supplementary criteria which are useful for its diagnosis. Results: Analysis of the 1450 cases of hydrocephalus of various etiologies stored in the data base obtained from the study for each type of hydrocephalus revealed that following types and conditions were associated with a neurologic deficit: (1) early fetal hydrocephalus, (2) overt neonatal hydrocephalus, (3) hydrocephalus associated with such severe brain malformations as hydranencephaly, holoprosencephaly and lissencephaly, (4) hydrocephalus associated with severe brain damage, (5) hydrocephalus associated with epilepsy, (6) hydrocephalus shunted late after detection, and (7) hydrocephalus complicated by a shunting operation. Conclusion: The postnatal functional outcome was significantly poor in fetal hydrocephalus diagnosed in the early gestation. Childhood onset hydrocephalus showed a poorer outcome than adult hydrocephalus.