Onyx embolization for the treatment of spinal dural arteriovenous fistulae: initial experience with long-term follow-up. Technical case report.

OBJECTIVE: Spinal dural arteriovenous fistulae (SDAVF) are the most common variety of spinal vascular malformations. The Onyx liquid embolic system (ev3 Neurovascular, Irvine, CA) was recently approved for the treatment of intracranial arteriovenous malformations, but its use to treat SDAVFs is not yet well established. We report our initial experience with Onyx embolization in the treatment of SDAVFs.
METHODS: Retrospective analysis of 3 consecutive patients with SDAVFs who were treated with the Onyx as the single treatment modality was performed. Demographic, clinical, and radiographic presentations as well as long-term outcomes were reviewed.
RESULTS: Four procedures were performed in 3 patients. In all cases, transarterial microcatheterization was performed with a Marathon microcatheter (ev3 Neurovascular) and Onyx-18 (ev3 Neurovascular) was used. All 3 patients were men (age, 75-78 years) and presented with progressive myelopathy. Two patients underwent only 1 procedure, with a single pedicle embolized to achieve angiographic cure. In the remaining patient, 2 procedures with embolization through 3 different pedicles from 2 adjacent levels were necessary to achieve angiographic cure. No procedure-related complications were noted. No evidence of residual or recurrent SDAVF was seen on magnetic resonance imaging (mean, 10.6 months; range, 7.1-14.6 months), angiographic (mean, 12.2 months; range, 10.2-14.9 months), or clinical (mean, 13 months; range, 10.2-14.9 months) follow-up examination.
CONCLUSION: Our initial experience suggests that the endovascular treatment of SDAVFs with the Onyx is feasible, safe, and highly effective, as it allows for a controlled penetration of the embolic agent into the draining vein. In this small series, we found no evidence of clinical, magnetic resonance imaging, or angiographic recurrence during the long-term follow-up period.