Arteriovenous malformations of the posterior fossa. Clinical features, treatment and results

We present our experience of 20 cases of arteriovenous malformations (MAV) of the posterior fossa. During the period 1991 1999 we prospectively collected radiological and therapeutic clinical data and the results obtained in all cases of adults whose arterio venous malformations were treated. We selected 20 of those who had MAV of the posterior fossa. The average age was 39.6 years (15 64). Thirteen (65%) were men. Most patients, 16 cases (80%) presented clinically with cerebellar haemorrhage, subarachnoid and/or intraventricular haemorrhage and 6 (30%) of the patients were admitted in coma. On the Spetzler and Martin scale: grade 1, 1 patient (5%); grade 11, 8 patients (40%); grade 111, 8 patients (40%) and grade 1V, 3 patients (15%). One patient had an associated pedicular aneurysm, another a supratentorial MAV and another patient had several cavernomas. Nine patients required external ventricular drainage, which in 4 cases became a permanent CSF drainage system. Endovascular treatment was used in 8 patients, radiosurgery in 2 and surgery in 9. Complete resection of the MAV was only possible in the patients treated by surgery (two patients had been treated previously by embolizations and radiosurgery). In this series there was a mortality of 20%, in all four cases due to recurrence of bleeding. Good results were obtained in 11 (55%) of the patients, but in the other 5 (25%) there were sequelas. The high percentage with haemorrhages as the form of presentation, with a much higher mortality than that of supratentorial MAVs makes more aggressive treatment necessary.