Surgical Management of Failed Endovascular Treatment for Spinal Dural Arteriovenous Fistulas

Abstract Objective Spinal Dural Arteriovenous Fistulas (SDAVF) are rare vascular malformations. Digital subtraction angiography (DSA) is the modality of choice to demonstrate the malformation prior to endovascular embolization or open surgical repair. Angiographically occult SDAVF have been previously reported. Surgical considerations in SDAVF with misleading angiography have not yet been assessed. This case-series will describe misleading angiographic findings in this unique condition and propose surgical technique modifications for it. Methods A retrospective evaluation of patients' charts and imaging files operated for SDAVF from 2018 to 2019 at a single institution was performed. All patients were referred to surgery following failure of endovascular embolization or due to clinical and radiographic deterioration in the presence of an angiographically occult lesion. The case-series was comprehensively reviewed and evaluated for surgical considerations in these lesions. Results Four cases were included in this series. Two patients were embolized prior to surgical repair but continued to deteriorate neurologically and the other two had failed embolization attempt impeded by a torturous vascular network. In all four patients, exploration was successful, yielding either improvement or stabilization of neurologic status. Indocyanine green (ICG) injection for microscopically-integrated fluorescent angiography contributed to the identification of the supplying vessels and confirmed the SDAVF closure. Conclusion SDAVF should be treated promptly after diagnosis. In cases with high suspicion for SDAVF with occult or misleading angiography, spinal exploration should be pursued with no delay. ICG-assisted microscopic angiography may contribute to exploratory spine surgery for SDAVF closure.