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

Background

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 anaesthesia 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.