Hydrocephalus and infratentorial tumors. Incidence, clinical picture, and treatment.

One may consider that the child with hydrocephalus complicating a primary brain tumor has two distinctly different diseases: 1) a neoplasm, and 2) hydrocephalus. The hydrocephalus may be obstructive, communicating, or (in the case of choroid plexus papilloma) hypersecretory. This paper presents the incidence, symptomatology, and management of hydrocephalus associated with infratentorial brain tumors in 156 children and with pineal tumors in 21 children, all treated by the first author during the period 1967 to 1979. Medulloblastoma was the most commonly encountered tumor. Of 117 children with cerebellar-fourth ventricle tumors, 110 had hydrocephalus, whereas 11 of 34 with brain-stem tumors and all 21 with pineal tumors presented with hydrocephalus. Of the total 143 patients with hydrocephalus, shunts were inserted before craniotomy in 123, with the interval between shunt insertion and craniotomy for tumor removal ranging from 1 to 21 days. Eighteen of these children required shunt revisions after craniotomy; 36 of 80 patients followed for 6 months or more had their shunts permanently removed, but it was necessary to reinsert the shunt from 5 days to 13 months later in 30% of these patients. Only 25 patients remained permanently shunt-free. It is considered that the placement of shunts before craniotomy is justified by the extraordinarily high incidence of papilledema and visual impairment associated with hydrocephalus. "Upward herniation" and dissemination of neoplastic cells through the shunting system are theoretical contraindications to precraniotomy shunt insertion, although the former is rare (3%), and there is no statistical evidence to support the latter.