The rate of major complications increases with occlusion of large portions of the AVM nidus in the same session. So, we recommend gradual occlusion of the AVM nidus, especially the large ones, in multiple sessions, as previously mentioned in other studies.The rate of transient focal alopecia in the Onyx group was higher than in the NBCA group. This reflects the higher rate of irradiation with Onyx injection than with NBCA injection, due to longer screening time with Onyx injection. Many cases in both groups showed significant improvement or disappearance of headache, even after partial occlusion of the AVM. Some cases in both groups showed also significant improvement or disappearance of their sensory or motor neurological deficit provoked by the previous steal effect of the AVM, even after partial occlusion of the AVM. On the other hand, some cases in both groups showed significant regression of epilepsy after partial embolization. As, there is no consensus in the literature about the improvement of epilepsy after partial or complete AVM embolization, it deserves to plan a randomized controlled trial, dedicated to assess the efficacy of embolization