Microsurgery for 67 intracranial arteriovenous malformations less than 3 cm in diameter

The surgical outcome in a series of small arteriovenous malformations (AVM's) that might have been considered optimal for radiosurgery is reviewed. In a total microsurgical series of 360 patients, 67 (19%) underwent resection of AVM's less than 3 cm in largest diameter, regardless of location. Many of these lesions (45%) were in locations that might be considered surgically inaccessible such as the thalamus, brain stem, medial hemisphere, and paraventricular regions. Complete angiographic obliteration of the AVM by microsurgical technique was accomplished in 63 patients (94%) with a surgical morbidity of 1.5% and no operative mortality. Patients with hemispheric AVM's had a cure rate of 100% and no neurological morbidity. Stereotactically guided craniotomy was used in 14 patients (21%) to locate and resect deep or concealed malformations. The results from five major radiosurgery centers treating similar-sized AVM's are analyzed. The authors' surgical results compare favorably with those from radiosurgery centers which, in their opinion, supports the conclusion that microneurosurgery is superior to radiosurgery, except for a small percentage of lesions that are truly inoperable on the basis of inaccessibility.