Evaluating the Role of Onyx Embolization in the Management of Spinal Dural Arteriovenous Fistulas: A 20-Year Single-Center Experience.

Abstract

Open surgery is widely regarded as the standard treatment for spinal dural arteriovenous fistulas (SDAVFs). However, endovascular treatment (EVT) with liquid embolic agents has emerged as an alternative. While N-butyl cyanoacrylate is often preferred for its superior penetration into draining vein, this study aims to assess the effectiveness of an embolization-first strategy using Onyx, drawing on 20 years of clinical experience. A retrospective analysis included 50 patients treated between 2004 and 2024. Only patients undergoing EVT as the first-line therapy for SDAVF were included. Overall, EVT achieved complete occlusion in 38 (76%) cases, with an additional 6 (12%) requiring adjuvant surgery resulting in definitive cure. In the remaining 6 (12%) patients, embolization of the feeding artery and fistula nidus led to permanent clinical improvement (n = 4, 66%) or stability (n = 2, 33%), supported by indirect fistula signs regression on follow-up magnetic resonance imaging. Onyx was solely used in 84% of EVTs, achieving a complete occlusion rate of 83%. Clinical improvement or stabilization was observed in 46 (92%) patients, with no recurrences in successfully treated patients. There was no EVT-related complication. Follow-up magnetic resonance imagings showed regression of perimedullary varices and regression or stability of myelopathy in all cases (n = 50, 100%). The embolization-first strategy, with adjuvant surgery when necessary, can achieve outcomes nearing those of purely surgical approaches. Based on our long-term experience, EVT with Onyx can result in complete and permanent cure of SDAVF in more than 80% of cases.