Microsurgical treatment of arteriovenous malformations in critical areas of the brain.

Between June 1981 and November 1989, 56 patients who had arteriovenous malformations (AVMs) in critical areas of the brain, in deeply placed sites or were of large size were excised using microsurgical techniques. In 44 cases one-stage surgery was used and in 10 cases deliberate surgical staging was performed. In four cases routine postoperative angiography revealed residual AVM. Further treatment was surgical in two cases, and focused radiation in two to achieve angiographically confirmed excision or obliteration of the AVM. Referral was following haemorrhage in 41 cases, progressive neurological deficit in nine cases and epilepsy in six cases. Forty-three patients made a good recovery, seven were fair, three had a poor result and three died. Three patients developed a new or increased deficit following surgery. Seven of nine patients who presented with neurological deficit improved. Seven of nine patients who had epilepsy and who had not bled are free of epilepsy, and are not receiving anticonvulsants on long-term follow-up. No new cases of long-term epilepsy have occurred following surgery. Microsurgical excision of cerebral AVMs even in critical areas of the brain carries a better outcome than the natural history of conservatively treated lesions. Surgery should be considered not only following haemorrhage, but also in cases presenting with progressive neurological deficit or epilepsy.