Arteriovenous fistula of the cervical spine

17. May, 2018

Case example

A 10 year-old dog presents with intermittent lameness of the left forelimb of multiple months duration and an acute onset of a sensory deficit of the right pelvic limb.

The computertomographic examination of the cervical spine shows a right ventral extradural compressive myelopathy at the level of C6/7, secondary to an arteriovenous anomaly of the vertebral plexus. (Figure 1) Its origin is the right subclavian artery. (Figure 2) and it drains into the left subclavian vein. (Figure 3)

Spinal arteriovenous fistulae are an uncommon disease with only a few case reports in the literature. The neurologic signs are secondary to haemorrhage, hypoxia, venous congestion and a mass effect. The “subclavian steal” phenomenon characterizes a change in blood pressure distal to the incomplete vascular occlusion, causing hypoxia and subsequently ataxia, visual impairment and syncopes.

In human medicine angiography is the gold standard for further characterization of the anomalous vessel, followed by endovascular occlusion via a coil or a liquid embolic agent.

Literature example:
“Computed Tomographic and angiographic assessment of spinal extradural arteriovenous fistula in a dog” Morabito et al., Can Vet J 2017 Mar; 58(3): 275-279
“Arteriovenous malformation of the cervical spinal cord in a dog” Hayashida et al. J Comp Pathol, 1999 Jul; 121(1):71-6

The diagnostic images – courtesy of Dr. H. Weniger