Microsurgical treatment of arteriovenous malformations of the brain in a defined population.

During the 10-year period from 1980 to 1989, 90 patients with cerebral arteriovenous malformations were seen at our institution. Two patients with large hematomas were moribund at admission, and no treatment was possible. Of the remaining 88 patients, nine were treated conservatively. Of these, six were too old and debilitated to undergo operations (the arteriovenous malformation was operable in four, inoperable in two), and three refused surgery. Of the 79 patients treated surgically, four died (5%) (three due to late rebleeding) and four are severely disabled (5%). The remaining 71 patients are functionally independent (90%). Microneurosurgery has made possible the excision of 90% of arteriovenous malformations; however, their surgery still remains a challenge for the neurosurgeon. The annual incidence of active arteriovenous malformation surgery was 0.9/100,000/year, and the ratio of arteriovenous malformation surgery to cerebral aneurysm surgery was 1:11. A few surgeons specializing in the surgery of arteriovenous malformations and aneurysms should be available in every country.