Spinal cord infarction as a complication of supratentorial cerebral arteriovenous malformation embolization

• Spinal cord infarction is a rare but devastating complication of endovascular procedures. • We present a unique case of spinal cord infarction complicated the supratentorial arterio-venous malformation embolization. • Anatomical variation of the anterior spinal artery in our patient created a watershed zone at the lower cervical spine. • Transient hypotension during the procedure most likely led to the critical hypoperfusion in this area and formation of the ischemic changes. • Patient developed a permanent motor deficit in his extremities with intact sensation. Infarction of the anterior spinal artery after embolization of a supratentorial AVM with Onyx has not been reported. We present a case of a male patient in the fourth decade of life who underwent an uneventful embolization of a Spetzler-Martin grade I supratentorial arteriovenous malformation (AVM) using Onyx-18 in preparation for surgical resection. The patient awoke from the anaesthetic with weakness in the bilateral arms below the C4 dermatome. His lower extremities were unaffected, and he had no thoracic dermatomal findings. Over the course of the next 4–6 h, he gradually lost the ability to move his lower extremities. Magnetic resonance imaging (MRI) demonstrated abnormal signal in the anterior spinal artery territory (ASA) in the cervical cord from C3 down to the cervicothoracic junction. Detailed study of the vertebral artery angiography demonstrates that the ASA arises from the bilateral vertebral arteries at the vertebrobasilar junction, but it is discontinuous, and muscular branches at the level of C5 reconstitute the ASA below C5. There is an angiographic discontinuity between the superior portion of the ASA and the lower half of the ASA at the level of C5, representing a watershed zone. This devastating complication, we speculate, was the result of a watershed infarction due to transient hypotension during the embolization procedure.