Approaches for arteriovenous malformation management

We started gamma knife surgery on May 28, 1991 and have treated 24 cases of arteriovenous malformation (AVM) during nine months. Based on our experience, various therapeutic policies for AVM management have been assessed. Radiosurgical procedures were quite safe and patients could return to preoperative activities the day after treatment. However, we had two patients whose malformations ruptured during and after radiosurgery. As the ideal goal of AVM management is complete obliteration of the nidus as soon as possible, direct surgery and intravascular surgery remain excellent treatments, especially for ruptures AVMs with intracranial hematomas. For the treatment of large AVMs in functional areas, combination therapies can be performed and intravascular embolization may be considered in order to reduce the volume of the nidus. However, the risk of embolization is still appreciable for AVMs in functional areas. Compartment irradiation using independent isodose lines of 50% may be useful for such high risk AVM patients, although a two stage radiosurgical procedure may also be considered. Selective angiography and magnetic resonance imaging are useful for the dose planning of these radiosurgical procedures. (author)