Further Experience in the Treatment of Cerebral Arteriovenous Malformations with Embolization Plus Surgery

Abstract

Seventy-five patients with cerebral arteriovenous malformations (AVMs) were treated with preoperative embolization followed by microsurgical resection. In 47 patients, the AVM was located in critical or eloquent areas; in 49 patients, AVM volume was over 20 cm3. Preoperatively, flow-directed embolization was performed in 11 early cases, and selective embolization with threads in the remaining 64 patients. The percentage of reduction of AVM volume averaged 37% after embolization. Eleven minor complications (transient neurological deficits, in 4 cases associated with ischemic areas and in 1 case with a small hemorrhage on CT scan) were observed after embolization; in one patient, a fatal intracranial hemorrhage occurred after embolization. When compared to flow-directed embolization, selective embolization was linked with decreased incidence of cerebral edema after surgery. When the percent reduction of AVM volume (after embolization) was 30% or more, the incidence of postoperative hematomas was significantly lower. There was no significant relation between timing of surgery after embolization and hyperemic complications or outcome. From a retrospective comparison of two groups of patients with similar AVM volumes (over 20 cm3) — those given combined treatment (n = 49) versus those treated by direct surgery only (n = 28) — intraoperative bleeding appeared to decrease in patients treated by embolization, and the incidence of postoperative edema was lower; moreover new major deficits and deaths were less frequent in patients treated by embolization. In conclusion, combined treatment with selective preoperative embolization and direct surgery may help the neurosurgeon in the treatment of large high-flow AVMs, reducing the risks connected with their surgical removal.