Endovascular management of spinal dural arteriovenous fistulas. A review.

OBJECT Spinal dural arteriovenous fistulas (DAVFs) are the most common spinal vascular malformations and can be a significant cause of myelopathy, yet remain inefficiently diagnosed lesions. Over the last several decades, the treatment of spinal DAVFs has improved tremendously due to improvements in neuroimaging, microsurgical, and endovascular techniques. The aim of this paper was to review the existing literature regarding the clinical characteristics, classification, and endovascular management of spinal DAVFs. METHODS A search of the PubMed database from the National Library of Medicine and reference lists of all relevant articles was conducted to identify all studies pertaining to spinal DAVFs, spinal dural fistulas, and spinal vascular malformations, with particular attention to endovascular management and outcomes. RESULTS The ability to definitively treat spinal DAVFs using endovascular embolization has significantly improved over the last several decades. Overall rates of definitive embolization of spinal DAVFs have ranged between 25 and 100%, depending in part on the embolic agent used and the use of variable stiffness microcatheters. The majority of recent studies in which N-butyl cyanoacrylate or other liquid embolic agents were used have reported success rates of 70-90%. Surgical treatment remains the definitive option in cases of failed embolization, repeated recanalization, or lesions not amenable to embolization. Clinical outcomes have been comparable to surgical treatment when the fistula and draining vein remain persistently occluded. Improvements in gait and motor function are more likely following successful treatment, whereas micturition symptoms are less likely to improve. CONCLUSIONS Endovascular embolization is an increasingly effective therapy in the treatment of spinal DAVFs, and can be used as a definitive intervention in the majority of patients that undergo modern endovascular intervention. A multidisciplinary approach to the treatment of these lesions is required, as surgery is required for refractory cases or those not amenable to embolization. Newer embolic agents, such as Onyx, hold significant promise for future therapy, yet long-term follow-up studies are required.