Outcome after the treatment of spinal dural arteriovenous fistulae: a contemporary single-institution series and meta-analysis

Abstract

Objective: Spinal dural arteriovenous fistulae (Type I spinal AVMs) are the most common type of spinal vascular malformations. The optimal treatment strategy has yet to be defined, and endovascular embolization is being offered with increasing frequency. A 7-year single-institution retrospective review of outcome with surgical management of Type I spinal AVMs is presented along with a meta-analysis of existing literature.

Methods: For the institutional analysis, a retrospective review of all patients who underwent treatment at our institution for Type I spinal AVMs was performed. Between 1995 and the present (the time frame during which endovascular treatments were available), 19 consecutive patients were treated. Follow-up was performed by clinical examination or telephone interview, and functional status was measured by use of the Aminoff-Logue score. For the meta-analysis, a MEDLINE search between 1966 and the present was performed for surgical, endovascular, or combined treatment of spinal dural arteriovenous fistula. These series were included in a meta-analysis to evaluate success and failure rates, complications, and functional outcome. Specifically, embolization and microsurgery were compared.

Results: For the institutional analysis, 18 of 19 patients were available for long-term follow-up after surgery. There were no surgical failures, but one complication was seen. Patients demonstrated a statistically significant improvement in gait and bladder function after surgery. For the meta-analysis, 98% of those patients treated with microsurgery had their dural arteriovenous fistulae successfully obliterated after the initial treatment, compared with only 46% with embolization, as judged by radiographic or clinical follow-up. 89% percent of patients demonstrated improvement or stabilization in neurological symptoms after surgical treatment. Few complications were demonstrated with either surgery or embolization.

Conclusion: At this point, surgery seems to be superior to embolization for the management of spinal dural arteriovenous fistula. The fistula is usually obliterated after the initial treatment, with few clinical or radiographic recurrences. The majority of patients either improve or stabilize after treatment. Few worsen, and the morbidity is minimal. It is reasonable to attempt initial embolization, especially at the time of the initial diagnostic spinal angiogram. The treating physicians and patients should be aware of the high chance of recurrence, and patients may ultimately require surgery or repeat embolization. After endovascular therapy, patients are committed to repeat angiography and probably embolization. For these reasons, it is the authors' opinion that surgery should be used as the first-line therapy for spinal dural arteriovenous fistulae.