Is surgical therapy needed for unruptured arteriovenous malformations?

A conservative attitude toward unruptured arteriovenous malformations (AVMs) has been based on the belief that surgical resection is too risky and that their natural history is benign. We have operated on 103 patients with a cerebral AVM. In the 49 patients with unruptured AVMs, there was no mortality, and the morbidity was 14.2%. Similarly, low surgical morbidity has been reported from several centers during the last few years. The chance of hemorrhage for both ruptured and unruptured AVMs is about 3% per year, and the combined morbidity and mortality of each hemorrhage is at least 40%. All patients with an AVM should be individually considered for possible surgical resection, whether or not they have bled.