Grading and staged resection of cerebral arteriovenous malformations.

The decision to recommend operative excision of an AVM should be based on an objective assessment of the long-term prognosis of the untreated lesion and the risks of surgery. We have developed a relatively uncomplicated, preoperative grading system for AVMs. This grading system will allow the surgeon to estimate the risk of completely excising a particular AVM. In our series, staged management was used to reduce the risk of excising large AVMs. These lesions were managed by preoperative transfemoral embolization, intraoperative selective embolization combined with feeding artery ligation and, finally, surgical excision. The stepwise throttling of large AVMs appears to minimize the risks of NPPB. The extensive AVM embolization and feeding vessel ligation integral to this staged approach serve another, equally important purpose--the control of intraoperative bleeding--a factor that previously limited the surgical excision of many large AVMs. Using this management strategy, we have successfully excised 25 exceptionally large AVMs with no mortality and only one seriously disabling, surgically related deficit.