Effectiveness and pitfall of embolization of cerebral arteriovenous malformations

We studied the course ofperisurgical complications of 66 AVMs and discussed the approapriate precautions. Of 66 patients with AVMs, 14 underwent postembolization surgical removal, and 43 underwent radiosurgery. Four patients were cured with total occlusion of their AVM by embolization alone. 48 patients achieved a more than 70% occlusion of the nidus. We observed 12 complications including 3 permanent and 9 temporary. Four complications occurred immediately after the embolization due to overembolization or thromboembolism, and 7 were observed several hours later which might have been caused by retrograde thrombosis or a chemical reaction to the glue. While presurgical embolization deepseated feeders must be embolized along with fistulous or high-flow feeders, 4 cases of 2nd embolization following radiosurgery showed that meningeal feeders developed or recanalized in cases embolized with absorbable particles. Thus, preradiosurgically, fistulous and meningeal feeders should be treated, and the nidus must be packed with embolic materials with no risk of recanalization. Successful nidus packing performed in 10 AVMs yielded a further nidus reduction before radiosurgery. The intranidal aneurysms which pose a high risk of rebleeding were also embolized. In order to avoid complications in the embolization of AVM, the angioarchitecture, hemodynamics and the relationship to brain function should be well recognized by preoperative functional imaging and superselective angiograms, and adequate embolic materials should be properly injected. As an embolization strategy, the priority of the target feeders should depend on the treatment to follow, and aggressive embolization of risky feeders or causing abrupt hemodynamic change should be avoided.