ARTERIOVENOUS-MALFORMATIONS IN THE BASAL GANGLIA AND THALAMUS - MANAGEMENT AND RESULTS IN 101 CASES

Object. Because arteriovenous malformations (AVMs) in the basal gangli a and thalamus are difficult to treat, the authors conducted a retrosp ective study to determine the best management strategy for these lesio ns. Methods. The authors reviewed the management and outcome in 101 pa tients with AVMs treated between 1971 and 1995. In 15 conservatively t reated patients, hemorrhage occurred in 71.4% (annual rate 11.4%), and the morbidity and mortality rates were 7.1% and 42.9%, respectively, during a mean follow-up period of 6.6 years. Total microsurgical resec tion was performed in 15 patients with no mortality resulting, but mot or function deteriorated permanently in three of them (20%). Postopera tive morbidity correlated well with the location of the AVM and with p reoperative motor function. In cases of lenticular AVMs without motor weakness, a postoperative decrease in motor function was significantly more common than in the remaining patients. In patients with motor we akness before surgery, AVMs in the thalamus or caudate nucleus were su ccessfully resected. Among 66 patients treated with gamma knife radios urgery, three had permanent radiation-induced neurological deficits, a nd three others experienced bleeding (new bleeding in one case and reb leeding in two). The treatment-associated morbidity rate was 6.7%, and the actuarial rate of complete obliteration was 85.7% at 2.5 years. I n five patients treated with embolization alone, the morbidity and mor tality rates associated with the procedure or bleeding were 40% and 20 %, respectively. The morbidity and mortality rates in the pre-gamma kn ife era were 22.2% and 22.2%, whereas those for the post-gamma knife e ra are currently 10.4% and 1.5%, respectively. Conclusions. These resu lts indicate that conservatively treated AVMs are more likely to bleed and thus produce a high incidence of patient mortality. Multimodal tr eatment including radiosurgery, microsurgery, and embolization improve d clinical outcomes by making it possible to treat difficult cases suc cessfully.