Introduction: Onyx has become a preferred treatment for cranial dural arteriovenous fistulas (cDAVFs) and arteriovenous malformations (AVMs), but the reported success for Type I spinal AVFs (sDAVF) remains limited. We review our experience with Onyx and report its limitations in the treatment of spinal AVFs in comparison to n-butyl cyanoacrylate (NBCA).

Methods: We retrospectively reviewed the Interventional Neuroradiology procedure database at Washington University for cases of sDAVF embolization. Patient charts and radiology reports were reviewed for fistula classification, treatment technique, and initial and follow-up results. Angiographic images were reviewed to confirm diagnosis, treatment and penetration of embolisate into the draining vein.

Results: From 2006 to 2011, a total of 20 patients with sDAVFs were treated via endovascular embolization. Seven patients were treated with Onyx, and 13 with NBCA. For type I AVF there were 9 treatments (7 patients) with Onyx and 10 treatments (10 patients) with NBCA. Of the 9 total treatments, Onyx successfully crossed the nidus into the draining vein in only 4 cases. Successful venous embolization was facilitated with positioning of the microcatheter to less than 5mm from the nidus in 3 of the 4 cases. The use of NBCA resulted in venous penetration in 8 of 10 cases, and short-term follow-up cure in 7 of 10.

Conclusions: Our experience with Onyx for Type I sDAVF embolization has been tempered by difficulty achieving venous penetration and consequently, a high rate of recurrence. For endovascular management of these fistulas, we favor NBCA or surgical treatment.

Patient Care: Offers another perspective in embolization of spinal AVF

Learning Objectives: Treatment of spinal AV fistulas

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