Strategy for the treatment of arteriovenous malformations

The treatment of arteriovenous malformations (AVMs) is still a challenging problem in the neurosurgical field. The deep-seated AVMs are a definite ind ication for radiosurgery for the small AVMs and with pre-embolisation for t he large AVMs. The superficial AVMs are a good indication for surgery. In t he case of small AVMs, surgery alone is a viable option; however, in the ca se of large AVMs, pre-operative embolisation is essential for prevention of NPPB (normal perfusion pressure breakthrough). Embolisalion alone cannot b e used, except for a small AVM in the non-eloquent cortex. Preoperative emb olisation makes surgery easy; however, It causes the surrounding cortex to infarct. Hyperperfusion may occur after the direct removal of high-flow lar ge AVMs, therefore postoperative management will be difficult in these case s. In eloquent cortex minimally invasive surgery is more reliable with resp ect to the morbidity produced. Therefore in cases of small AVMs In the func tional colter, direct surgery is the only choice. In cases of high-flow lar ge AVMs, surgery and postoperative management are risky because at NPPB. Th erefore pre-operative embolisation followed by surgery is a better choice. In high-flow AVMs, local blood circulation is not decreased by temporary cl ipping of the feeding arteries. So we recommend temporary clipping of all f eeding arteries, even away from the nidus where it is easter to control ble eding. (C) 2000 Harcourt Publishers Ltd.