EEG MONITORING DURING ENDOVASCULAR EMBOLIZATION OF CEREBRAL ARTERIOVENOUS-MALFORMATIONS

Arteriovenous malformations (AVMs) may have a bad prognosis. Endovascu lar embolization with cyanocrylate represents nowadays an important in itial step in a staged treatment, that later may include surgery or ra diotherapy. Embolization may induce significant changes in the dynamic s of the cerebral circulation, some of which may provoke neurological sequelae. Therefore assessment of potential complications is usually d one by using a superselective amytal test, during which small doses of amytal are injected directly in the pedicle that is going to be embol ized. In spite of an extensive use of the EEG during endovascular embo lization its evaluation in terms of benefits and limitations is not av ailable. Such evaluation is therefore the aim of this work. EEG monito ring was performed during endovascular embolization of 19 patients; a large majority of patients presented large AVMs, with Spetzler indexes around IV or V. The main results were as follows: (1) EEG changes at baseline were significantly correlated with the AVM size and the Spetz ler index but were unable to predict the difficulties in the embolizat ion; (2) during amytal tests EEG positivity reached 35% and consisted mainly in ipsilateral slow focal activity; (3) in some cases embolizat ion was performed in spite of transient EEG changes. It was found that focal or diffuse abnormalities in the lower frequency range, even whe n slight, could be followed by clinical hazards (3 out of 11 cases); ( 4) EEG monitoring was important in the prediction, evaluation and prog nosis of clinical complications.