Vertebrovertebral arteriovenous fistula (VVAVF) is a rare vascular disorder characterized by an abnormal direct connection between the extracranial vertebral artery (VA), or its branches, and nearby vertebral venous structures [3]. While some VVAVFs occur as a result of trauma or iatrogenic injury, spontaneous cases have been associated with connective tissue disorders, including neurofibromatosis type 1, Ehlers-Danlos syndrome, and fibromuscular dysplasia [2,5,7].

Once symptoms develop, including pulsatile tinnitus, neck pain, swelling, or neurological manifestations due to venous congestion, surgical or endovascular ligation of the fistula should be considered. However, achieving definitive closure while preserving the parent artery can be challenging due to high-flow shunting. Reconstructive treatments employing stents have recently been reported [6,9,13]; however, concerns remain regarding durability and the requirement for extended antiplatelet therapy.

Here, we report the case of a high-flow VVAVF that was successfully treated by stentless reconstructive embolization using a double-balloon jailing technique. This technique involved navigating two balloon microcatheters separately through transarterial and transvenous routes to achieve targeted embolization of the fistula. Additionally, we introduce a microsnare-guided retrograde exchange method as a practical bailout when direct transvenous navigation is difficult.

Treatment of VVAVFs aims to relieve symptoms and prevent neurological sequelae caused by venous reflux or the steal phenomenon [4,11]. Historically, endovascular deconstructive occlusion of the affected VA has been the most common treatment approach. In a review of 280 cases of VVAVF, most (spontaneous, traumatic, or iatrogenic) were managed through parent artery occlusion [1]. Deconstructive treatment can achieve high rates of fistula closure; however, it carries a risk of ischemic complications, arising from altered hemodynamics and thromboembolism, even when robust collateral circulation is observed [1]. Additionally, when symptoms are nondisabling (e.g., tinnitus), preserving the parent artery may be preferable—especially in younger patients or those with connective tissue disorders. Prior reports suggest that unilateral VA occlusion can increase hemodynamic stress on the contralateral VA, potentially contributing to contralateral aneurysm formation [8].

With advancements in endovascular devices and techniques, various reconstruction strategies have been developed. Adjunctive balloon and stent techniques enable targeted embolization while preserving the parent artery [9,10]. However, creating a stable coil mass is challenging in high-flow or columnar-type fistulas that lack a venous-side scaffold. In these situations, tight packing from the venous side may be necessary, often requiring many coils, which increases the risk of mass-effect-related symptoms and the overall treatment cost. Combining coils with liquid embolic agents has been reported [14]; however, this approach carries the risk of arterial migration, especially when multiple fistulous sites are present. Furthermore, covered stents and flow diverters may be useful reconstructive options for high-flow VVAVFs [6,13]; however, they require antiplatelet therapy and may perform suboptimally when the parent artery is poorly visualized owing to flow steal or is markedly tortuous. This can increase the risk of incomplete closure or thromboembolism [6]. Conversely, the double-balloon jailing technique does not leave a permanent implant in the parent artery, which minimizes antiplatelet exposure and is particularly appealing in traumatic presentations. Importantly, this approach enables subsequent options; if shunting persists or recurs, a flow diverter or covered stent can be used as a reconstructive bailout. Additionally, parent artery occlusion remains feasible when there is a collateral circulation.

A distinctive feature of this approach is the separate navigation of the arterial and venous pathways using the two balloon microcatheters. This enables device withdrawal without traversing the fistula, thus aiding in preserving the integrity of the coil mass. Balloon microcatheters have been used in remodeling techniques [12]; however, to our knowledge, no previous study has described the use of two balloon microcatheters through transarterial and transvenous routes for VVAVFs. In this case, complex septations within the SCS and highflow shunting obstructed transvenous navigation. We advanced an arterial microcatheter antegrade into the IJV, captured it with a microsnare introduced through a venous microcatheter, and retracted the coupled system retrograde to the venous pouch. During this maneuver, both operators maintained neutral tension on the coupled system by synchronizing gentle venous traction with a slight arterial counter-push. The venous balloon microcatheter was then delivered to the target pouch under controlled conditions by exchanging the venous microcatheter. To reduce the risk of dislodgement during exchange, the venous microcatheter was prepositioned across the fistula with its tip in the VA. This microsnare-guided exchange strategy utilizes shunt flow as a physiological guide, allowing for the selection of the shortest course through the septated venous corridors and avoiding forceful catheterization from the jugular side. This principle may extend to selected high-flow fistulas with unfavorable transvenous access, but its applicability depends on specific anatomical conditions and procedural controllability. Direct arterial-to-venous microsnare capture may also be feasible in selected cases; however, we did not attempt it because of concerns about balloon damage.

A theoretical concern is that excessive inflation of the venous balloon microcatheter, used as a temporary scaffold, could enable the coil mass to relax and migrate after deflation. This risk was addressed by first placing a long framing coil from the venous pouch into the fistula to create a robust anchor. Then, we stabilized the embolization microcatheter with the two balloon microcatheters for bidirectional “jailing,” which enabled dense and progressive compaction within the fistulous tract. Finally, we deflated the balloon microcatheters in a stepwise manner—first the venous balloon microcatheter and then the arterial balloon microcatheter—under low-flow conditions, ensuring coil stability. The venous balloon microcatheter was sized and inflated to achieve appropriate wall apposition rather than forceful compression. The final coil mass was self-retaining. No migration of the coils occurred during or after balloon deflation.

We achieved complete angiographic obliteration; however, long-term recanalization or recurrence through the development of collaterals cannot be excluded, as embolization was limited to a short segment. Therefore, long-term imaging follow-up is essential, and additional treatment should be considered if recurrence is detected. Further validation of this technique in recurrent cases is necessary through a larger series and accumulated clinical experience.

Double-balloon jailing enables dense, fistula-targeted embolization of selected high-flow VVAVFs with favorable anatomical configurations without requiring stent implantation. This stentless approach may reduce prolonged antiplatelet exposure while preserving bailout options. Furthermore, microsnare-guided retrograde exchange can facilitate device delivery when transvenous navigation is challenging.