Abstract
We reviewed 70 arteriovenous malformations (AVMs) treated with embolization over 5 years and investigated the treatment strategies for virtual AVMs simulating various types and situations with a quetionnaire sent to 17 affiliated hospitals. Of 70 patients with AVMs, 14 underwent postembolization surgical removal, and 47 underwent radiosurgery. Four patients were cured with total occlusion of their AVM by embolization alone. 61 patients achieved a more than 70% occlusion of the nidus. We observed 12 complications including 3 permanent and 9 temporary. Based on these data, we created the chart of treatment strategy for AVMs. There is an absolute indication of embolization for large, high flow AVMs as well as possible bleeding sourses such as intranidal or feeder aneurysms. Deep-seated feeders must be embolized presurgically along with fistulous or high-flow feeders, and fistulous and meningeal feeders should be treated before radiosurgery. The nidus must be packed with embolic materials with no risk of recanalization. The responses to a questionnaire revealed the tendency of less aggressive surgical extirpation for difficult AVMs, and more dependence on radiosurgery with or without embolization. The general strategy with more than 70% of consensus was following three: 1) radiosurgery for small AVM without bleeding, 2) embolization plus radiosurgery for large AVM with ischemic events, and for large, eloquent one and deep-seated one with minor hemorrhage, 3) surgical removal for small, middle-sized AVM with large hematoma except for middle-sized eloquent and deep-seated ones. Although the improvements in radiosurgery may narrow the indication of embolization, it still plays an important role for high grade AVMs by enhancing the effectiveness of the secondary treatment. The inidicaiton of embolization should be decided taking various factors about the angioarchitecture of AVMs as well as the patients' situations into considerations. The safest multi-axial method should be used for the benefit of patients with AVMs.
