Endovascular procedures are rapidly supplanting open surgery as the first-line treatment for various vascular anomalies. Among these, vertebral-venous fistula (VVF) is a rare vascular disorder described as an anomalous high-flow shunt between the extracranial vertebral artery and its adjacent venous plexus, without an intervening capillary network [1]. While many VVFs occur due to trauma, they may also arise spontaneously in syndromic or dysplastic conditions of the vascular wall—such as neurofibromatosis, fibromuscular dysplasia, or Ehlers-Danlos syndrome [1].

Though most frequently located in the cervical spine, where a majority remain asymptomatic [2], VVFs can become symptomatic when dilated extradural venous plexuses compress the thecal sac or nerve roots, causing myelopathy [3]. Due to the high-flow nature of the shunt, patients may present with a bruit or tinnitus, and occasionally cerebellar signs (vertigo, ataxia) from a vascular steal phenomenon [4]. Scarce case reports and small series guide current management strategies, as no comprehensive classification or protocols exist to date. Thus, further published experiences, such as this one, are critical to expanding our understanding of these uncommon but potentially debilitating lesions.

vertebral-venous fistula (VVF) is a rare vascular spinal disorder characterized by a direct, high-flow shunt between the vertebral artery and the veins of the vertebral plexus [1]. In a review by Aljobeh et al., among 276 patients with cervical VVF—the most commonly affected region—82 presented with myelopathy [5]. A literature search on VVF associated with neurofibromatosis revealed only 36 reported cases, which aligns with the association found in our patient.

Clinically, VVF commonly manifests with compressive symptoms due to a dilated extradural venous plexus indenting the root sleeve or the thecal sac [4]. Besides bruit or tinnitus caused by the high-flow shunt, patients may exhibit cerebellar symptoms such as vertigo and ataxia triggered by a vascular steal phenomenon [6]. In the study by Aljobeh et al., the presence of a bruit was the most frequent presenting sign [5]. Our patient similarly presented with cervical compressive myelopathy accompanied by a cervical bruit on auscultation.

No consensus or standardized classification scheme yet exists for VVF. However, in a study by Costa et al., VVF was grouped into two broad categories based on the blood flow through the fistulous connection and the number of arterial feeders. This flow can be high or low [7]. Consequently, a high-flow “Type A” VVF involves a direct shunt between the vertebral artery (VA) trunk and surrounding veins, whereas a low-flow “Type B” VVF is fed indirectly by dural or muscular branches of the VA. Each broad category further subdivides according to whether there is a single or multiple arterial feeder(s). In our patient, a high-flow, multi-feeder right vertebro-venous fistula was found.

Doppler ultrasonography and CT angiography are typically the first-line modalities to identify a suspected VVF. A six-vessel digital subtraction angiography (DSA) is considered essential to delineate the lesion’s arterial supply, venous outflow, and any potential leptomeningeal drainage [8]. While VVFs are generally fed by the vertebral arteries or their branches, contributions from the internal or external carotid artery trunk and branches have been described. This underscores the need for thorough vascular mapping. Additionally, brain and spinal MRI help distinguish VVF from other cranio-cervical pathologies [9]. Our patient initially exhibited spastic quadriparesis, and an MRI suggested OPLL-like changes. However, a normal CT (with no calcification) alongside an arterial bruit prompted a CT angiogram, ultimately revealing a VVF. We advocate incorporating CT angiography in cases of compression on MRI but normal CT, especially in syndromic scenarios.

The principal aim in treating vertebro-venous arteriovenous fistulas is complete occlusion of the pathological shunt to eliminate aberrant vascular channels. A myriad of options have been explored in literature with promising results (Table 1). Generally, low-flow VVFs may be amenable to serial angiographic observation, whereas high-flow VVFs demand shunt obliteration to prevent arterial steal [7]. Although spontaneous resolution has been documented, it remains exceedingly rare [13].

Today, endovascular approaches predominate, being minimally invasive and circumventing the extensive bleeding risks associated with open surgery in multiple-feeder or high-flow lesions [10]. Sacrificing the parent artery that harbours the fistula typically proves most effective, but can risk vertebrobasilar ischemia; thus, selective coil packing may suffice if there is a single feeder or a small orifice [5]. In more complex cases, balloons or covered stents are alternatives. Detachable balloons, for example, permit repeated inflation/deflation before final detachment, optimizing positioning and fistula occlusion [11].

A review by Silva et al. identified endovascular trans arterial embolization using an ethylene-vinyl alcohol copolymer (Onyx) as a frequent approach for such lesions [12]. However, particulate embolic agents are discouraged in high-flow fistulas due to displacement risk under rapid flow conditions [14]. Our patient exhibited a high-flow fistula with confirmed robust flow from the contralateral vertebral artery on DSA. Consequently, the decision was made to occlude the parent right vertebral artery proximal and distal to the fistula, with minimal neurological compromise expected.

A systematic review reported a 3.3% rate of neurological morbidity after VVF treatment [5]. Minor complications commonly included neck pain and headache, while major ones comprised ischemic or haemorrhagic events. Reperfusion injury—though rare—can be devastating after large-flow VVF embolization [14]. Our patient experienced no adverse sequelae and demonstrated favorable recovery at one-year follow-up.

VVF is a rare entity presenting with diverse anatomical complexities which precludes the formation of a structured classification or intensive guidelines on its management which prompts the need of more data on this disease. Symptoms of cervical compression with syndromic association should raise suspicion of its presence. Due to the wide spectrum of signs and symptoms, this entity may mimic other pathologies of the cervical spine and the need for CT angiography and DSA is indispensable. As in the case report, endovascular techniques are found to be safe and effective treatment options with endovascular coiling, use of detachable balloons, covered stents and combined embolization procedures all reportedly effectual in literature.