Use of the Cavitron ultrasonic surgical aspirator and evoked potentials for the treatment of thalamic and brain stem tumors in children.

We subtotally removed nine pediatric central gliomas (five brain stem and four thalamic) with the Cavitron ultrasonic surgical aspirator (CUSA). Greater than 70% of the tumor was removed in eight of the nine cases. Evoked potentials were monitored during six of the operations. Of the six children who were operated on with monitoring, four had no deficit and two had single cranial nerve palsies. Of the three children who were operated on without evoked potential monitoring, one had no deficit, one was in a permanent state of obtundation, and one died of a pulmonary embolus 6 weeks postoperatively. Because the prognosis of children with malignant astrocytomas correlates with the extent of tumor removal, extensive tumor removal with the CUSA is probably indicated for some children with relatively discrete, enhancing central gliomas. Evoked potential monitoring may be useful during such operations.