Cisternography with isotopes following posterior fossa surgery in children.

Surgery of posterior fossa tumors is afflicted with some important problems. One of these is the postoperative communicating hydrocephalus. According to the literature this form of hydrocephalus is found in 10-30% of all children operated on; but a permanent shunt is necessary in only 8-18%. Aim of the present investigation was to find out disturbances of cerebrospinal fluid (CSF)--circulation and--reabsorption after posterior fossa surgery. Therefore 25 children ranging in the age from 3 to 12 years were examined on the basis of isotope cisternographic studies 8 to 21 after the operation. In 4 cases all parameters of pathological CSF-dynamics were found which required a permanent ventriculo-atrial shunt. 21 children showed a minimal or significant accumulation of the isotope in the posterior fossa but a normal circulation and a sufficient clearance on later scans. In these cases neither a temporary nor a permanent shunt was necessary. These findings are confirmed by follow-up examinations between 2 and 3 years.