The authors evaluated surgical outcome and natural history of the arteriovenous malformation (AVM) in the posterior fossa according to anatomical location of the AVM. Seventeen patients with AVM in the posterior fossa have been managed at our department since 1970, 14 of whom presented with intracranial hemorrhage, and 3 presented progressive focal symptoms. Out of 17 patients, 10 of the AVM were located in the cerebellum, 4 in the cerebellopontine angle (CP-angle), and 3 within the brainstem. In the 10 cerebellar AVM, operations were directed at primary resection in 9 cases, and 1 patient refused operation. Six out of 9 cases had good results and 3 had significant morbidity. In the 4 CP-angle AVM, 2 patients underwent direct operations with good results. In the 3 brainstem AVM, 1 patient with epipial AVM underwent an operation with good result. In the non-surgical group, 3 out of 5 patients died.
The AVM located in the cerebellum are resected safely, and epipial or subpial AVM in the CP-angle or brainstem are resectable with acceptable morbidity. The deep-seated brainstem AVM would have a poor natural history.
