Twenty-eight patients treated for arteriovenous malformations (AVMs) of the brain had staged therapy consisting of multiple surgical procedures or endovascular embolization followed by surgical treatment. There were 10 men and 18 women, aged 15 to 60 years (mean, 34 years). The clinical symptoms were those associated with intracranial hemorrhage in 13 patients, progressive neurological deficit not due to hemorrhage in 6, intractable headache in 5, and seizures in 4. Four groups were identified based upon the reason for staging therapy. Thirteen patients with large high flow AVMs (Group A) had staged treatment because of the risk of normal perfusion pressure breakthrough. The initial afferent artery occlusion was accomplished surgically in 9 patients and by endovascular embolization in 4. Postoperatively, no patient in this group had malignant cerebral edema or intracranial hemorrhage suggestive of normal perfusion pressure breakthrough, but 1 patient had an intraventricular hemorrhage after initial embolization. In 9 patients (Group B), the AVM had a complex multiple arterial supply that precluded resection from a single operative exposure. Seven had supratentorial AVMs, and 2 had AVMs of the posterior fossa. In 6 of these cases, the AVM was located in the midline and received bilateral arterial input. Six patients had staged surgical procedures, and 3 had an initial endovascular embolization followed by operation. Two patients had intracerebral hemorrhages, one after an initial surgical procedure and another after initial embolization. In 4 patients (Group C), the AVM had a major dural component that was treated separately from the parenchymal component. In 3 of these patients, embolization through the external carotid artery satisfactorily obliterated the dural component; in the remaining patient, a persistent internal carotid supply necessitated resection of the dural malformation. The parenchymal component was excised surgically in 2 patients. Two patients (Group D) had separate surgical procedures to treat an aneurysm associated with a parenchymal AVM. Overall, 19 of 28 patients had complete excision and 9 had partial obliteration of their AVMs. Late follow-up of 27 patients at a mean of 18.6 months showed that 16 patients were in excellent condition and 8 were in good condition. Three patients were in poor condition with debilitating neurological deficits. One patient had a delayed intracranial hemorrhage 22 months after incomplete obliteration of her AVM. Staged treatment of selected AVMs of the brain may avoid the occurrence of normal perfusion pressure breakthrough.(ABSTRACT TRUNCATED AT 400 WORDS)