Onyx cast thrombectomy: bailout during thalamic AVM embolization.

Microsurgical resection, radiosurgery, and endovascular embolization are the three different treatment approaches to cerebral arteriovenous malformations (AVMs). Although microsurgical resection remains the most desirable curative option and radiosurgery is often first choice in deep located/eloquent unruptured AVMs, transarterial or transvenous embolization may be pursued for ruptured AVMs not amenable to surgical resection. Most complications during endovascular treatment are related to hemorrhage; however, liquid embolic fragment migration or parent vessel occlusion are also possible and can lead to ischemic events. We present a case of endovascular Onyx (Medtronic, Minnesota, USA) embolization of a ruptured thalamic AVM complicated by Onyx reflux into the proximal posterior cerebral artery causing complete vascular occlusion. We demonstrate a bailout technique1-4 using combined stent-retriever and aspiration catheter to dislodge and retrieve the refluxed Onyx cast while maintaining total occlusion of the initially targeted arterial AVM feeder (video 1).neurintsurg;jnis-2023-020832v1/V1F1V1Video 1.